The magazine for the international power industry November 2014

SAFETY MEASURES FOR COAL PLANTS

TIPS FOR SELECTING THE RIGHT DRIVE

NEW SOLUTION FOR GRID FLEXIBILITY

NORTH AMERICA’S DRIVE TO CUT CO2

www.PowerEngineeringInt.com

1411PEI_C1 1 11/10/14 9:54 AM

Introducing the QSK95 Series of high-horsepower generator sets.

When it comes to power generation, more is better. More horsepower.

More performance. More reliability. But what if you could also have a

generator set that takes up less space in your facility, lowers installation

costs and reduces maintenance? At Cummins Power Generation, we

call this The Power of More — and with the QSK95 Series of generator

sets, it can be yours. Rated at up to 3,500 kW (3,750 kVA) and designed

with a smaller footprint, the QSK95 delivers the highest kilowatt per

square foot ratio in its class.

The Power of More.

Our energy working for you.TM

© 2014 Cummins Power Generation Inc. All rights reserved. Cummins Power Generation and Cummins are registered trademarks of Cummins Inc. “Our energy working for you.” is a trademark of Cummins Power Generation Inc.

Visit our website to see how the QSK95

can give you The Power of More.

CumminsPowerOfMore.com/QSK95Series

For more information, enter 1 at pei.hotims.com

1411PEI_C2 2 11/10/14 9:54 AM

1

POWER ENGINEERING INTERNATIONAL

Contents

Free Product InfoYou can request product and service information from this issue. Simply click on the link below that will provide you access to supplier companies’ websites,

product information and more http://pei.hotims.com

If you are considering suppliers or buying products you read about in PEi, please use this service. It gives us an idea of how products are being received to help us continually

improve our editorial offering and it also lets our advertisers know that you are a PEi reader and helps them to continue supporting the free distribution of your magazine.

On the cover Increasingly fast and sophisticated real-time plant analysis software is unlocking improved predictability, reliability and fexibility for combined-

cycle plant - p6. Cover image credit: Siemens

Features

6 The rise of the digital power plant

How real-time analysis and simulation software is bringing

operational benefts for combined-cycle plants.

12 Driving a low-carbon path for American power

A look at North America’s new generation of low-carbon

power generation technologies.

20 An engineer’s guide to selecting a drive

How to fnd the optimal motor for an application while

avoiding design errors and saving money.

24 Strengthening safety in mills and silos

Equipment selection and operating criteria are vital for

reducing fre risk in coal storage facilities.

28 Developments in power plant fre detection

The challenges and solutions involved in fre detection for

power plant operators.

Power Engineering International November 2014

4 Industry Highlights

52 Diary

51 Ad Index

NOVEMBER 2014/// VOLUME 22/// ISSUE 10

www.PowerEngineeringInt.com

30 A fresh perception of ESP

Retroftting electrostatic precipitators with a high-frequency

switch mode power supply can reduce particulate emissions

and improve performance.

36 Advances in vacuum circuit-breakers

Technology advances now allow vacuum circuit-breakers to

be used in generator switching applications.

40 Dynamic line rating: a solution for fexibility

Dynamic line rating technology can increase the capacity of

overhead transmission lines while reducing congestion.

44 A new approach to nuclear decomissioning

Meeting the challenges of decommissioning multiple nuclear

sites with a programmized approach.

46 Desuperheaters rise to new challenges

How a new generation of desuperheaters is addressing

today’s 50- and 60-Hz combined-cycle power generation.

Canadian CCS project offers carbon-reduction breakthrough - p12

Source: SaskPower

1411PEI_1 1 11/10/14 9:40 AM

OCTOBER, 1947

CHUCK YEAGER

BREAKS

THE SOUNDBARRIER

For more information, enter 2 at pei.hotims.com

1411PEI_2 2 11/10/14 9:45 AM

BARRIER

JUNE 2014, SENTRONTM

LD 8000 NGEO

SHATTERSTHE DRAININTERVAL

Petro-Canada is a Suncor Energy businessTMTrademark of Suncor Energy Inc. Used under licence.

Call 1-866-335-3369 or visit lubricants.petro-canada.com for more information.

Yesterday, 8,000 hours was unthinkable.

Suddenly, anything less could be unacceptable.

New SENTRON LD 8000 Natural Gas Engine Oil (NGEO) is so advanced

it provides up to 8,000 hours between drains. Satisfy your need for proof

with our Money-Back Guarantee Trial. Visit SentronTrial.com for details.

1411PEI_3 3 11/10/14 9:45 AM

4 Power Engineering International November 2014 www.PowerEngineeringInt.com

Industry Highlights

Subsidies – can’t live with them, can’t live

without them: at least that’s how it often

seems in the power industry.

They often dominate debates at energy

conferences around the world, and it was no

different at POWER-GEN Middle East in Abu

Dhabi in October.

“Subsidies are the biggest ailment that

afficts the Middle East power sector,” said Dr

Hisham Khatib, honorary vice-chairman of the

World Energy Council.

Speaking at the opening ceremony of

POWER-GEN Middle East, Dr Khatib said that

Middle East power generation subsidies use

8.4 per cent of the region’s GDP and account

for half of the energy subsidies in the world.

He said the continued use of subsidies was

the key factor in the Middle East’s rocketing

energy demand – up to 8 per cent a year for

the last decade, which is almost four times the

fgure for any other country in the world.

Yet he added that “subsidies beneft the

rich, less the poor”.

And while he said that there were “shy”

attempts to phase out subsidies, he stressed

that these needed to be made a “top priority”

and put a price tag on this of $140 billion of

investment in the next fve years – which rises

to $230 billion if transmission and distribution

work is included.

Dr Khatib was joined on the stage at the

opening ceremony by Russia’s deputy energy

minister Yury Sentyurin, who used his speech

to stress the importance of international

collaboration on energy projects.

He said that “the global power markets are

becoming more dynamic yet less predictable”

and that the “silver bullet” to secure energy

supplies for countries around the world was

“politically unbiased co-operation”.

Mr Sentyurin also later spoke at Russia Day,

a special event being held as part of POWER-

GEN Middle East, which returned to Abu Dhabi

for the frst time in 12 years.

He told a packed audience that

renewables were going to play a key role in

the Russian Federation’s future energy mix.

He said a target had been set of having

6 GW of renewables online by 2020, which

would account for 4 per cent of the Russian

Federation’s energy mix.

“We are doing our utmost to be in line

with global trends and develop these lines of

generation,” he said.

Also speaking at Russia Day was Adnan

Amin, director of the International Renewable

Energy Agency (IRENA), who said that

meeting the world’s rising energy demand

with the current global energy mix would be

“catastrophic”.

Mr Amin said that any move to meet

demand with fossil-fuelled technology would

“lock in pollution and climate change”.

He said what was needed was a shift to

more renewable technologies and added

that this was already happening.

“Investment in renewables is booming,”

he said. “More than 100 GW of capacity has

been added every year for the past years.”

He said fnancing of renewable projects

was getting cheaper because the perceived

risks associated with ‘green’ technologies were

dropping.

Amin added that “Russia can play a very

important role in the renewables story” and

that the Federation has “vast potential” to

embrace clean technologies.

Russia plans to derive 4 per cent of its

power from renewables by 2020, which

Adnan said was “a viable target”. He added

that if Russia – which has applied to join the

International Renewable Energy Council – hit

this target, it would displace six million tonnes

of carbon dioxide a year.

IRENA has just published a new report

called REthinking Energy in which the

organization explores “the changes that are

transforming the way we produce and use

energy, and how they will affect governments,

businesses and citizens alike”.

In the foreword to the report (look out for

our feature in next month’s PEi), Amin says that

it is “no longer a matter of whether but of when

a systematic switch to renewable energy

takes place – and how well we manage the

transition”.

Probably true, even if he’s talking in

decades. What is certainly true – in the Middle

East and every other region of the world – is his

next statement: “The power sector is changing

so fast that policymakers are fnding it hard to

keep up.”

“Power generation subsidies account for 8.4 per cent of the Middle East’s GDP and make up half of the energy subsidies in the world.”

Kelvin Ross, Editor, www.PowerEngineeringInt.com

Follow PEi Magazine on Twitter: @PEimagzine

Follow me: @kelvinross68

1411PEI_4 4 11/10/14 9:45 AM

WE

ST

IN

GH

OU

SE

E

LE

CT

RIC

C

OM

PA

NY

L

LC

Reliable Solutions. Regulatory Compliant. Long-term Support.

Protect the critical digital assets of your power plant with

Westinghouse’s suite of cyber security solutions. We offer a

specialized approach and worldwide experience implementing

cyber security products and services for the operating fl eet and

the next generation of new plants.

Westinghouse has the expertise and technology to meet today’s

global cyber security nuclear regulations.

From a thorough systems vulnerability assessment through

mitigation solutions and long-term maintenance, Westinghouse

has your cyber security needs covered.

To learn more about cyber security, visit us at

www.westinghousenuclear.com

@WECNuclearWestinghouse

Electric Company

CYBER SECURITY

WE HAVE YOUR PLANT

COVERED UNDER LOCK

AND KEYSTROKE

© M

aksim

Ka

ba

ko

u -

Fo

tolia

.co

m

For more information, enter 3 at pei.hotims.com

1411PEI_5 5 11/10/14 9:45 AM

Today’s rate and speed of digital

development is phenomenal,

and this rate of change is

mirrored in the power generation

industry: rapid development

of information technology is

enabling increasingly sophisticated operation

of combined-cycle gas turbine plant. Big data,

the Internet of Things, wireless mesh networks

and cloud computing are all making their

mark.

Increases in computing speed and

capacity have enabled collection, analysis

and storage of increasing volumes of

information. New software platforms are used

to interpret data and feed back information

enabling optimization of operations and

maintenance. As the speed and sophistication

of real-time analytics increase, insights can

be promptly looped back into the decision

process.

The physical world is increasingly getting

online as objects, devices and machines

acquire more digital intelligence, while

advances in connectivity mean that objects

can be wirelessly integrated into information

networks. The last few years have seen a huge

increase in the use of wireless sensors and

instruments in power plants. These observe and

monitor their environment, communicating

information about temperature, pressure, fow

and vibration from the heart of the power

plant back to the control centre.

Big data is generating datasets that are

increasing exponentially in both complexity

and volume. Analyzing, storing and applying

this data is a considerable challenge.

Companies such as GE are building cloud-

Operations and maintenance

With increasingly fast and sophisticated real-time plant analysis and simulation software comes improved predictability, reliability and fexibility – all of which look certain to bring operational benefts for combined-cycle plant, writes Penny Hitchin

Big data unlocks better effciency

Intelligent analytics collect vast amounts of data

Credit: Dreamstime

6 Power Engineering International November 2014 www.PowerEngineeringInt.com

1411PEI_6 6 11/10/14 9:46 AM

For more information, enter 4 at pei.hotims.com

In DNV GL we unite the strengths of DNV, KEMA, Garrad Hassan

and �������������������� �. Our 2500 energy experts take a

���� ������������������������������� ������������� ����������

������������������������ ���������������������������������������

������������ �� ������������������� ���� ���������������������

www.dnvgl.com/energy

DNV

KEMA

GARRAD HASSAN

GL RENEWABLES CERTIFICATION

DNV GL in the energy sector

EXPERIENCE

MATTERS

SAFER, SMARTER, GREENER

1411PEI_7 7 11/10/14 9:46 AM

8 www.PowerEngineeringInt.comPower Engineering International November 2014

Operations and maintenance

Going forward, plant performance and asset condition will be monitored with increasing reliability

Credit: Siemens

HRSG detail from Ebsilon Professional heat balance software

Credit: VTU Energy

based services with intelligent analytics to

collect and combine vast amounts of data

to use in industries which include power

generation.

Software modelling

Ambient and load conditions signifcantly

affect gas turbine and combined cycle

performance, thus process simulation plays a

key role in every large project.

Sophisticated software is used to

simulate the thermodynamics and drive the

optimization of the power plant. Experts can

compile detailed models of gas turbines and

all major components and simulate plant

operations under the entire range of ambient

and load conditions. Linking market models

incorporates fnancial and environmental

information so that operational costs can be

projected.

Austrian software specialist VTU Energy

is currently modelling a large combined

water and power plant for a bidder for an

IWPP (Independent Water & Power Producer)

contract in the Middle East.

The developers pull together technical

information from vendors of gas turbines,

desalination units and other components

which VTU feeds into its overall plant model for

use in the bid process.

The company uses the Ebsilon Professional

heat balance software and its own Gas

Turbine Library to build an accurate plant

simulation model. This is used to fnd a

commercial optimum while meeting the

requirements of the tender and producing the

most competitive tariff.

The contract is for a power and water

purchase agreement for 25 years and bidders

must submit around 100 documented

operating points so the government can

evaluate the bid in technical terms. VTU’s Dr

Josef Petek explains why the simulation plays

a vital role in putting together the bid:

“There is a very strong emphasis on the

documentation of the technical capability

of the plant. You are going for a long-term

relationship that includes performance

guarantees. The government owns the gas

and is the sole buyer of the products, electricity

and water, so understanding the effciency

and capacity of the power plant is essential.”

Thermal power plant generation has

traditionally been dictated by load demand,

but the increasing supply of intermittent

renewable energy, notably in Europe, is

transforming the pattern of demand, so that

combined-cycle plants are called upon to

provide fexible peak load. For an existing

power plant operating in a deregulated

competitive market, accurate prediction of

plant capacity and fuel consumption under

expected conditions for the days ahead is

essential. Weather information (notably the

likely availability of wind, hydro and solar)

should be factored in to the equation.

In order to bid into the market, plant

operators need the ability to make accurate

predictions of future operational costs. Under

a capacity market operators will be looking

to predict how best to operate in the next two

weeks, informing their bids into the market.

Petek says: “In the past, in a regulated

market, you could look back at the price of

operation to make a price. Now the historic

price of power is less signifcant: you have to

bid into the future, looking at where the market

is going, depending on the renewables.”

Factors will include likely demand and

weather forecast for the next two weeks.

“Based on this predictive work, you feed in

your fossil generation and look at how many

startups do you want to use in the next two

weeks, what will be the cost of stop-and-go

generation. Does it make sense to have low-

load parking position? Does it make sense

to reduce load to a minimum because

electricity price is so low that it does not pay

to shut down the plant and you are maybe

paid for quickly ramping up and producing if

immediate need arises?”

In the past, effciency was the priority for

combined-cycle plant, but on networks that

give priority dispatch to renewable sources

it is increasingly fexibility, startup time and

low load operation. Operators will rely on

emerging predictive software to provide the

answers.

1411PEI_8 8 11/10/14 9:46 AM

www.PowerEngineeringInt.com 9Power Engineering International November 2014

Operations and maintenance

Big data and cloud computing

Number-crunching the mounting volumes of

data from a power plant requires additional

processing power and broadband capacity.

The aim is to increase effciency of both

operations and asset maintenance through

improved understanding of the plant

processes.

Eric Kauffman, Software & Analytics

Strategy Leader at GE, says: “We have created

a cloud-based version of our Effciency Map

product which brings data back centrally.

This enables us to get better data by adding

a reconciliation element that would be too

complex to do on-site. It also enables our

engineers to provide a second set of eyes for

the customer.”

He cites an example of the benefts:

“Calculations using plant sensors might show

a curve with uncertainty rate of 1–2 per cent.

By using a combination of a physics model,

a precision test and the data reconciliation

algorithm we have been able to demonstrate

overall uncertainties of below 1 per cent.

“This gives customers better visibility to the

existence and location of problems in the plant

– and, more importantly, where the problem

is not. It also gives a better understanding of

plant capability so purchasers are able to buy

fuel more effciently and reduce the amount

of safety margin that traders put into their bid.

Kauffman estimates that, in some

deregulated US markets, an improvement of 1

per cent in accuracy can be worth over half a

million dollars per year in a typical combined-

cycle power plant. Increasing the amount

of data from within the power plant means

installing smart devices and instruments. GE

has done a lot in development around smart

bus technology to reduce the number of

terminations required to install the technology.

Reducing wired connections saves parts,

costs and time.

Mark Hachenski, executive product

manager at GE, explains: “By using smart bus

technology, we dramatically reduced the

installation time by decreasing the number of

wires and terminations. For instance, we have

reduced 3600 terminations down to 1800, a

50 per cent reduction in the plant.”

Hachenski gives an example of how

hardware developments go hand in hand with

advances in communications technology: “In

addition, smart bus technology can provide

higher reliability for customers.

“In the past we used hydraulic fuel skids

which would only annunciate four or fve

analogue diagnostics. Moving into the twenty-

frst century, with a smart bus electronic fuel

skid we get 60 digital health bits to come back

into our system. This provides better visibility of

what is going on for quicker actions to resolve

problems.”

However sophisticated the software and

remote control systems, human operators

are an essential part of the system. It is not

helpful to swamp them with masses of data:

it is important that the information presented

by the software is relevant, accessible and

comprehensible.

Hachenski explains GE’s approach to

making screens intuitive and user-friendly:

“One of the things we have done is to

redesign the screen ‘look and feel’ so that

operators can easily and quickly see how

the plant is running. We are trying to visually

represent what is important to the operator.

We do not want to burden the operator with a

tonne of information or with too many alarms.”

Alarms alert the operator to a change, inform

the operator of the nature of the change,

and guide the operator toward a course of

corrective action.

GE leverages its new GE Software business

and team of user experience experts to help

make the software and experience more user-

friendly. The interface was tested by bringing

in operators to use simulated screens while

observers watched them walk through various

alarms or faults in the system.

Hachenski says: “Customers tell us that

operators make mistakes as they try to

manually start up systems. We are looking at

how to automate the process so that a startup

screen walks them through a step-by-step

sequence. However while some customers

want operators to follow this, others don’t want

operators interfering, so the software interface

must accommodate different operators.”

Wireless mesh networks

The development of low-cost, fexible wireless

networks has opened up the potential for

additional data collection from the heart

of the power plant, increasing real-time

For more information, enter 5 at pei.hotims.com

www.rs-seliger.de

ñ safely

Load quickly

1411PEI_9 9 11/10/14 9:46 AM

10 www.PowerEngineeringInt.com

Operations and maintenance

Power Engineering International November 2014

understanding of the way that processes

and components operate. This also allows

for performance validation and improved

maintenance practices, including predictive

approaches.

Traditional networks rely on a small number

of wired access points or wireless hotspots

for communication. In a wireless mesh

network, the network connection is spread

out among numerous wireless mesh nodes

(smart transducers and devices acting as

transmitters that function in the same way

as a wireless router) and share the network

connection across a large area. Information

travels wirelessly across the network from one

mesh node to the next.

The nodes are programmed with software

that tells them how to interact within the larger

network, and dynamic routing means they

automatically choose the quickest and most

reliable path. If one node is inoperative, the

rest of the nodes can still communicate with

each other, directly or through one or more

intermediate nodes. Wireless mesh networks

can self-form and self-heal.

Only one gateway needs to be physically

wired to a network connection, which then

wirelessly shares its connection with all other

nodes in its vicinity.

Effciency Solutions Manager Jeff Williams of

Emerson Process Management is enthusiastic

about the potential of wireless mesh networks

to improve data collection from power plants.

“Wireless networks have been available

for a number of years,” he says, “but today we

see them with expanded functionality. Wireless

area networks in power plants are being used

in parallel with the plant’s real-time distributed

control system. A wireless instrument can

collect information that was previously

unavailable due to the impracticality and

expense of hardwiring in a diffcult-to-reach or

harsh environment.

The data can then be integrated through

the wireless network and sent to the control

system so that it can be analyzed and

performance adjustments made to the

equipment. This leads to the best possible use

of plant assets.”

In the past a small number of wireless

instruments may have been used around

the plant. Williams says that they are being

increasingly used for a range of performance

testing and diagnostics functions.

“Power generators started using wireless

instruments and networks to validate

performance of new equipment, but are

now fnding that the accuracy of wireless

instrumentation is so good that it can be

used it as a backup to wired devices and to

verify plant performance. A wireless network

can support dozens of instruments used to

validate performance.”

The ease with which wireless

instrumentation can be deployed compared

to hardwired devices means that many new

data sets are becoming readily available.

As Williams says, “It is easy to hang a wireless

transmitter onto a piece of equipment for

temporary analysis – getting this information

is something which would have previously

required the use of many portable instruments

as well as associated manpower.”

Wireless networks and sensors are being

used to measure increasing amounts of

temperature, pressure, vibration and fow data

from the heart of the power plant. Intelligent

devices can be coupled to intelligent networks

and the information can be analyzed remotely,

locally or through a combination of both.

Having collected the data, the control

system’s software is able to analyze it against

historical baseline data for predictive

maintenance or other performance

evaluation.

Williams says: “As we go forward, I think we

will see a merging of technologies so that

we can watch the plant in real time from the

distributed control system and use simulation

that is closely tracking that performance to

run ‘what-if’ scenarios that will enable us to

make process adjustments for more effcient

operations. Synchronizing the simulation with

real-time plant operation will allow asset

managers to optimize plant performance,

reduce environmental footprint and keep

consumable costs as low as possible.”

Going forward…

Software specialists, plant manufacturers and

operators say they are always learning from

the data. Going forward, better analytics, a

high degree of physics models plus big data

look certain to bring operational benefts.

Performance will be diagnosed in real

time, sustaining output and effciency, while

asset condition will be monitored and

predicted with increasing reliability.

Sophisticated software and smart

instruments can improve performance,

enabling plant to get online faster from a hot

or cold start and despatch faster. Software

can co-ordinate between the steam turbine

and the gas turbine to reduce startup time

by 50 per cent.

The rate of change looks set to continue

and accelerate as developments in

hardware, software and communications

yield increasing amounts of information

about conditions at the heart of the plant.

GE’s Hachenski says: “We are learning every

day. The amount of information we are

getting that we didn’t have before gives us so

much more visibility. We have only scratched

the surface of fguring out how to take it to

the next step.”

Penny Hitchin is a journalist focusing on

energy matters.

Visit www.PowerEngineeringInt.com for more information i

Human operators are still an essential part of the system

Credit: Emerson Process Management

1411PEI_10 10 11/10/14 9:46 AM

© 2013 by AMETEK Inc. All rights reserved.

The new WDG-V.Impressing even theworld’s most demandingcombustion manager.

The new AMETEK Thermox WDG-V extractive combustion analyzer offers

industry-leading safety support. First in its class to be third-party certified for

SIL-2 implementation in safety-instrumented systems, the WDG-V provides

a complete solution for combustion process control and safety.

Reliable detection of low-combustion oxygen and/or high CO in a fired heater

or boiler is critical to burner management system effectiveness. The WDG-V

analyzer monitors hot, wet flue gas to minimize excess oxygen, lower

NOx emissions, and improve operating efficiency in power generation

and petrochemical refining. It can also monitor methane levels to

assure safe burner startup and shutdown.

The all-new WDG-V. Combustion management and safety capabilities

so good, they make this guy jealous. Learn more at www.ametekpi.com.

For more information, enter 6 at pei.hotims.com

1411PEI_11 11 11/10/14 9:46 AM

Although the US lags behind

Europe’s policymakers in

efforts to address carbon

emissions from the power

sector, under the Obama

administration the Environ-

mental Protection Agency (EPA) has moved to

tackle carbon dioxide output from electricity

generation.

In June the EPA issued a proposal for a

so-called Clean Power Plan, under which

guidelines will be set for states in order to

address greenhouse gas emissions from

existing fossil fuel-fred generation assets.

Refecting that different states have different

mixes of sources and opportunities, the EPA

plans to deliver state-specifc, rate-based

goals for CO2 emissions from the power sector.

Currently under consultation, a fnal ruling

on the plan is due in June 2015. States are now

attempting to identify a path forward using

either current or new electricity production

and pollution control policies to meet the

proposed programme’s goals. These plans

are due in June 2016, though under some

circumstances states will have until 2018 to

deliver their proposals.

Power plants account for roughly one

third of all US greenhouse gas emissions and

while there are limits in place for emissions of

pollutants such as arsenic, mercury, sulphur

dioxide, nitrogen oxides and particulates, until

recently the US has been largely resolute in its

rejection of constraints on carbon emissions.

However, in June 2013 President Obama

issued a presidential memorandum directing

the EPA to complete greenhouse standards

for the power sector under the auspices of the

Clean Air Act.

As a result, by the time the proposed plan is

fully implemented in 2030, the EPA aims to cut

carbon emissions from the power sector by

30 per cent below 2005 levels nationwide, as

well as cut particulates, nitrogen oxides and

sulphur dioxide by more than 25 per cent as a

coincidental beneft.

This, says the EPA, will avoid up to 6600

premature deaths annually and provide up

to $93 billion in climate and public health

benefts. Simultaneously, the agency expects

Carbon abatement

A confuence of factors is driving the North American power sector down a low-carbon road. Responding to customer demands, OEMs are expanding the capabilities and material composition of their products in order to meet effciency demands and develop a new generation of technologies, fnds David Appleyard

Driving a path for North

American power

Canada’s Boundary Dam is the frst commercial-scale post-combustion CCS process on a coal-fred power plantCredit: Sask Power

12 Power Engineering International November 2014 www.PowerEngineeringInt.com

1411PEI_12 12 11/10/14 9:46 AM

For more information, enter 7 at pei.hotims.com

1411PEI_13 13 11/10/14 9:46 AM

14 www.PowerEngineeringInt.com

Carbon abatement

Power Engineering International November 2014

the measures to reduce electricity costs by

roughly 8 per cent through increasing energy

effciency.

Ravi Krishnan, founder of global marketing

and strategy consultancy frm Krishnan &

Associates, highlights the policy context for the

US, but also the challenging market structures

which have existed to date, saying: “The US

market was obviously expecting some future

CO2 emission norms for power plants. However,

there were no monetization mechanisms

such as a national cap-and-trade system,

penalties, tax credits or subsidies for power

producers to avail themselves of. Therefore,

unlike Europe, there are fewer pre-combustion,

post-combustion or advanced combustion

technologies being demonstrated in the USA.”

Certainly, the nation appears to be

making up for lost time. Measures to address

emissions from existing generating facilities

follow proposals announced in September

2013 that set emissions standards for new-

build projects, a plan also developed under

Obama’s Climate Action Plan.

Under this proposal, new large natural

gas-fred turbines are limited to 1000 pounds

of CO2 per MWh (about 450 kg/MWh), while

new coal-fred units would need to meet a limit

of 1100 lb/MWh.

However, the American Coal Council

(ACC) said the EPA’s revised carbon pollution

standard for new power plants sets an

emissions limit for coal “that cannot be met

given current technology. Thus, the practical

effect of such a rule would be to stop the

construction of any future coal-fuelled

generation capacity in the US.”

This is a point echoed by Krishnan, who

says: “The US is moving away from coal and

it is unlikely that any new supercritical or ultra-

supercritical power plant will be built in the

future.”

Building on market trends

The EPA’s guidelines for existing facilities build

on trends already underway in the power

sector that are resulting in a cut in carbon

intensity, both from existing power plants and

across the evolving generation portfolio as a

whole.

As part of the proposed measures, the EPA

offered four ‘building blocks’ that it believes are

central to state measures to achieve portfolio-

level reductions in carbon intensity. The EPA

identifes measures to make existing fossil-

fuelled plants more effcient and suggests

despatching lower-emission sources, such as

natural gas, more often.

In particular, the emergence of cheap

and abundant shale gas has seen the

marginal cost of coal-fred capacity become

increasingly uncompetitive.

Scott Nolen, Global Technical Solutions

Leader at GE Power & Water’s Distributed

Power business, highlights the impact of shale

gas on cutting US carbon emissions: “The most

remarkable thing is the transformation of the

generation mix in the US driven by economic

forces. The dynamism of the US oil and gas

industry has created a great reduction

in power generation from coal, and the

generation mix has seen the biggest beneft

in terms of carbon footprint and that’s driven

just by economic forces.” As a recent example,

Nolen cites the hub pricing for gas outside

New York City, where the natural gas price

went to $1.70 per million BTU. “There is no way

coal can compete with that; it’s due to this

tremendous amount of supply that’s driven

that change,” he says.

Carbon capture and storage

Don Ryan, who manages the advanced

technology group at Babcock & Wilcox

Power Generation Group, explains that setting

carbon emission limits for coal-fred plants

only marginally above the demonstrated

emissions from a gas turbine combined-

cycle plant makes carbon capture and

storage a mandatory element for new coal-

fred capacity in the US. “Where we see the

regulations for new units is that, even with the

best-available, highest-effciency boiler and

steam turbine technology, you would need

partial carbon capture to get to the EPA limits,”

he says.

The best coal-fred technology on the

market right now features ultra-supercritical

steam conditions with pressures in the

3700–4000 psi range and steam temperatures

of 1110–1130oF. However, as Ryan explains:

“That doesn’t get you down to the CO2

The Petra Nova Carbon Capture Project is expected to capture 90 per cent of the CO2 in the processed fue gas from an existing unit

Credit: NRG

1411PEI_14 14 11/10/14 9:46 AM

For more information, enter 8 at pei.hotims.com

1411PEI_15 15 11/10/14 9:46 AM

16 www.PowerEngineeringInt.comPower Engineering International November 2014

Carbon abatement

emission level of a gas turbine combined

cycle without the addition of carbon capture

to a coal-fred boiler.”

As a result, North America has seen some

recent advances in CCS technology. Indeed,

NRG’s carbon capture business recently broke

ground on a 240 MW project at Unit 8 of the

610 MW WA Parish power plant in Fort Bend

County, southwest of Houston, Texas.

The WA Parish Petra Nova Carbon Capture

Project is a commercial-scale system that

is expected to capture 90 per cent of the

carbon dioxide in the processed fue gas from

an existing unit. When complete in 2016, the

project is expected to be the world’s largest

post-combustion carbon capture facility

installed at an existing coal plant.

In October, NRG announced that the

majority of the excavation needed to begin

building was complete, allowing drilling of the

approximately 800 piles that will serve as the

plant’s foundation to begin. NRG has formed

a 50/50 joint venture with JX Nippon Oil & Gas

Exploration Corp to build and operate the

Petra Nova Carbon Capture Project.

The captured CO2 will increase oil

production at the West Ranch oilfeld some

130 km away, jointly owned by Petra Nova and

Hilcorp Energy Co. Enhanced Oil Recovery

(EOR) is expected to boost oil production

at the feld from around 500 barrels per

day (bpd) to approximately 15,000 bpd.

A US Department of Energy grant of up to

$167 million has been awarded to the

$1 billion project as part of the Clean Coal

Power Initiative (CCPI) programme while

additional funding will come from loans of

$250 million and equity contributions from

both NRG and JX Nippon.

The project will be constructed under a fxed-

price contract by a consortium composed of

Mitsubishi Heavy Industries Americas and The

Industrial Company using the KM-CDR Process

jointly developed by MHI and Kansai Electric

Power Co.

October also saw the offcial inauguration

of SaskPower’s Boundary Dam project,

claimed as the world’s frst post-combustion

commercial-scale CCS process on a coal-

fred power plant.

Located in Estevan, Saskatchewan,

Canada, the C$1.4 billion ($1.25 billion)

rebuild project at Unit 3 of the 824 MW coal-

fred power plant generates 110 MW. CCS will

reduce carbon emissions by 90 pe cent and,

when fully optimized, the process will capture

up to one million tonnes of carbon dioxide

annually. The captured CO2 will be used for

EOR. Babcock & Wilcox Canada was engineer,

manufacturer and constructor of the critical

components to retroft the boiler under a

$107 million contract.

The government of Saskatchewan

invested C$240 million in the demonstration

project. Canadian economy minister Bill Boyd

noted: “This project is important because

it is applicable to about 95 per cent of the

world’s coal plants.” Likewise Luke Warren,

chief executive of the Carbon Capture and

Storage Association, commented: “It is hoped

that Boundary Dam will form part of a much-

needed commercial proof point that the

economics make sense.”

However, the economics of CCS technology

are still tenuous, as Krishnan explains: “Future

development of CCS technology will depend

on its cost, CO2 transport and storage

mechanisms, natural gas prices, regulatory

factors and the monetization of CO2 emissions.

Presently the CAPEX of CCS projects and

technology solutions is extremely high.”

This is a point echoed by B&W’s Ryan, who

notes that the FutureGen research project on

oxy-fred combustion, being developed in the

US state of Illinois, has been delayed by the

challenges of raising commercial fnance.

The project’s total capital cost (planning,

design and construction) is approximately

$1.65 billion, of which DOE will contribute

$1 billion and the private sector will contribute

the remainder.

Says Ryan: “There’s a piece of the funding

that the equipment suppliers are putting into

it, the US DOE are putting into it and there’s a

piece that we needed to go out to commercial

fnancial institutions. It’s been delayed due to

working out the terms with the commercial

fnancing institutions to get the last piece of

funding.”

The FutureGen Industrial Alliance was

formed to partner with the DOE on the

FutureGen 2.0 project to retroft an existing

plant. Construction was due to begin on both

the plant and the CO2 pipeline and storage

facility in 2014, with commercial operations

originally scheduled for autumn 2017.

Gas-fred generation and fexible reciprocating engines are increasingly economically attractiveCredit: GE

1411PEI_16 16 11/10/14 9:46 AM

Redefine your expectations of anti-corrosion coatings with AvantGuard® by Hempel.eddefifine your expectatiions off a

Hempel introduces AvantGuard®, a new

innovative anti-corrosion technology, based on

activated zinc and locked into our new range of

high performance protective coatings.

AvantGuard® reduces the effects of corrosion

and offers advanced protection. This increased

durability has been proven in extensive tests.

Redefining protection with reduced rust creep

and enhanced corrosion protection

Redefining durability with improved

mechanical strength

Redefining productivity with greater working

tolerances in different climatic conditions and

with high DFT’s. Less repair work needed.

AvantGuard®

Redefining anti-corrosion

For more information:

Email: avantguard@hempel.com

Visit: www.hempel.com/avantguard

For more information, enter 9 at pei.hotims.com

1411PEI_17 17 11/10/14 9:46 AM

18 www.PowerEngineeringInt.comPower Engineering International November 2014

Carbon abatement

As Ryan says: “They’re expensive projects

and you have to build pilot and demonstration

plants to get everyone comfortable that they

can add this technology to their plant.” He

adds: “We’ve been pleased with the DOE

support. They are seeing this to be the future of

coal-fred generation.”

An alliance between commercial and

state parties is also behind Canada’s Canmet

advanced coal-fring research project.

Between 1993 and 1995, CanmetEnergy

invested over C$4 million in building the world’s

frst advanced oxy-fuel combustion pilot-scale

research facility. Since its commissioning in

1995, CanmetENERGY’s CO2 R&D Consortium

is now in Phase 9, which is developing a CO2

capture and compression unit.

Challenging economics

But even with government support, the

economics of CCS can be challenging. For

example, in late September Leucadia National

Corporation announced that it had decided

not to proceed with further development of

the greater Lake Charles project based on

“fnal estimates of the likely ultimate cost”.

The decision came despite a December

2013 announcement from the DOE that it

would support the project to the tune of

$261.4 million under its Industrial Carbon

Capture Sequestration (ICCS) programme.

The petcoke-fred gasifcation plant was to

transport the CO2 to the West Hastings oil feld

for use in EOR. The estimated total cost of the

Lake Charles CCS project was $435.6 million.

The CCS project was to include two Lurgi

Rectisol Acid Gas Removal (AGR) units and

was designed to capture approximately

89 per cent of the CO2 produced.

Nonetheless, there are efforts to further

commercialize CCS technology in the US. In

April SaskPower and Vattenfall signed a fve-

year agreement to explore opportunities

for collaboration on CCS knowledge and

technologies. More recently, Shell Cansolv,

the subsidiary of Royal Dutch Shell behind the

technology used at Boundary Dam, agreed

a deal with Technology Centre Mongstad

(TCM) in Norway for further testing of the CO2

capture process. The testing was scheduled to

start in the third quarter of this year and will last

for approximately fve months.

Given the challenges of developing

economically viable CCS technology – it is

no coincidence that the projects that have

been developed in North America to date are

based at older coal-fred plants and coincide

with opportunities for EOR – the opportunities

for carbon reduction are based on alternative

approaches. As Krishnan explains: “Given the

early-stage development of the affordable

large-scale carbon capture technologies and

associated high CAPEX of transportation and

storage, I believe that the industry will focus on

increasing effciency by innovative equipment

upgrades, best practices and switching to

currently abundant natural gas.”

He continues: “The new EPA carbon

pollution emission guideline for stationary

sources will obviously result in new innovative

approaches outside of CCS to meet the

proposed targets. Power producers will

seriously look at increasing the effciency of

fossil fuel power plants through upgrading

technologies. Switching to coals that will

improve the heat rate of the units and reduce

its utilization will also be employed.”

Krishnan concludes: “In recent years,

marginal or ineffcient coal-fred power plants

have been under tremendous pressure to

lower their cost of generation to improve the

despatchability of their units. As a result, several

innovative boiler effciency improvement

technologies through retrofts, combustion

controls and fuel switching have been

incorporated. These strategies have resulted in

some modest improvement in CO2 emissions.”

Ryan highlights the focus on more effcient

combustion technologies: “About two years

ago we were fortunate to get a contract with

AEP to build the frst [US] ultra-supercritical

unit which is in the just-under-4000 psi steam

pressure range, but the steam temperatures

are up to the 1100–1150 range. That gave a

5 per cent to 6 per cent improvement in heat

rate over the traditional supercritical cycles.”

He adds: “We’re involved in a consortium

of companies here in the US to develop

advanced supercritical technology. That is

pushing the steam pressures up to 5000 psi at

the turbine inlet.”

He points out the challenges of materials

development in achieving these steam

conditions, saying: “The single biggest area

we’re working on now is to make sure we

understand the properties of the material, that

it’s going to withstand those pressures and

temperatures, have the life expectancy that

utilities like to see, and be able to fabricate

and repair the material in the feld. We’re in

the process of designing a small test facility to

actually run some components at the same

steam temperatures. We expect that to be

done next year, and then another year or two

from there we will have the ability to test some

of these components.”

Michael Gradoia, Manager of Power

Generation Product Marketing for GE Power

and Water, also highlights the challenges

of reducing carbon intensity with power

generation products. He says: “Gas turbine

effciency is primarily a function of fring

temperature and compressor pressure

ratio. There is a need for materials that can

withstand those higher temperatures, and

cooling technologies that allow you to reduce

the amount of air used for cooling that is

therefore not used for power.”

For example, GE’s latest products, the HA

gas turbines, utilize single crystal alloys in the

turbine section. Illustrating the challenges,

Gradoia adds: “When looking at a turbine

section, there are components that are

operating at about 400 degrees above

the melting point of the base metals, and

advanced coatings and cooling technologies

are what enable that part to do its job while

providing a reliable service life.”

On improving the effciency of existing

coal-fred assets, Gradoia says: “We can help

enhance the effciency of existing units by

retroftting the steam turbines with the latest

blading and sealing technology.”

Similarly, B&W is looking at developing

technologies and techniques to enable units

to operate more effciently at reduced load.

The US low-carbon future

More than 25 US states have already set energy

effciency targets, and more than 35 have set

renewable energy targets. Meanwhile, it is

evident that the DOE will pursue additional

constraints on carbon.

Ryan says: “In terms of where we think it’s

going at some point down the road, it’s hard

for me to imagine that higher levels of carbon

capture, up to and including 100 per cent,

aren’t going to be required.”

He concludes: “I think it’s a matter of time,

we just have to keep working on development

and getting it to a commercial state.”

David Appleyard is a freelance journalist

focused on the energy, technology and

process sectors.

Visit www.PowerEngineeringInt.com for more information i

1411PEI_18 18 11/10/14 9:47 AM

YOU AIN’T SEEN

NOTHING YETThe new benchmark in electric valve actuators

All will be revealed

Valve World Expo D¸sseldorf December 2nd ñ 4th, 2014

Hall 3 Booth D36

info@sipos.de, www.siposseven.com

STAY AHEAD. STAY SIPOS

P R O F I T R O N

For more information, enter 10 at pei.hotims.com

1411PEI_19 19 11/10/14 9:47 AM

Right from the initial selection of

a drive, a designer has to make

careful considerations when

looking for the optimal motor for

their application. Determining

the torque and speed, selecting

a pneumatic motor from suppliers’ catalogues

and clarifying the size and connections

required for the machine – it sounds simple.

But unfortunately it is not that easy, and a rude

awakening may follow if, after installation, the

selected pneumatic motor does not produce

the power required. Determining the problem

may take weeks; in the worst-case scenario the

entire drive may have to be redesigned and

purchased again. Therefore it is worthwhile to

talk to the specialists at the beginning of the

drive design phase.

Deprag Schulz has developed a simple

guide with six steps to follow so that nothing

is forgotten.

The selection of a pneumatic motor is

not diffcult. But, particularly with pneumatic

systems, there are many factors which can

decisively infuence the power of an air motor.

If, for example, when installing a motor it is

found that too short a hose has been chosen,

then this will drastically reduce the torque of

the motor.

You can imagine that the developer does

not necessarily have the length of hoses at

the forefront of their mind when designing the

machine; equally; the connectors between

the flter units and oiler are not considered to

be particularly relevant. But it is exactly these

throttle points which ultimately determine

whether the machine works correctly and if

the motor provides the right torque.

Steps to selecting the right motor

So what are these steps for the selection of

the right motor? First of all, the drive system

best suited to the customer’s application must

be chosen. Then the materials of which the

external parts of the motor are composed are

determined. After these initial decisions, the

theoretically required motor power can be

calculated and all performance-infuencing

factors can be taken into consideration.

The fourth step is the integration of the

motor into the complete system of the

machine. You have to decide how the motor

will be connected to the machine and

which gears are required. Perhaps a brake

Motors and drives

Selecting a drive involves careful consideration when looking for the optimal motor for a given application. Dagmar Dübbelde looks at how to avoid design errors and save money

An engineer’s guide to selecting a drive

For use in potentially explosive environments, ATEX certifcation is an option

Credit: Deprag Schulz

20 Power Engineering International November 2014 www.PowerEngineeringInt.com

1411PEI_20 20 11/10/14 9:47 AM

Through the Alternative Energy Source Incentives

Program (Programa de Incentivo ‡s Fontes

Alternativas ñ PROINFA), a total of

41wind power projects have been put into

action, spurring the still nascent industryís

development throughout Brazil.

Because of the program, another,

19 biomass thermal stations, powered

by rice husks and sugarcane bagasse, are in

operation with the support of ELETROBRAS.

ELETROBRAS is committed to generating clean and renewable energy. The majority of the energy

produced by the company derives from these sources.

Cutting-edge projects such as Megawatt

Solar, implemented in Brazilís South Region,

and Xapuri, in the state of Acre, employ solar

photovoltaic panel technology.

ELETROBRAS is one of the leading producers of electric energy in Brazil. In this light, it is encouraging

to know that a substantial portion of this energy stems from clean and renewable sources. In

addition to tapping hydroelectric power, one of the cleanest known sources of energy, ELETROBRAS

��������������������������������������������������� ���������������������������������������������

Brazilís energy sources and leveraging the related industries. These initiatives have helped transform

the Brazilian energy grid into one of the industrialized worldís most renewable systems.

It is for these reasons that ELETROBRASís work stretches as far and wide as Brazil itself.

eletrobras.com

Ministry ofMines and Energy

B R A Z I L I A N G O V E R N M E N T

For more information, enter 11 at pei.hotims.com

1411PEI_21 21 11/10/14 9:47 AM

22 www.PowerEngineeringInt.comPower Engineering International November 2014

Motors and drives

will be necessary in order to ensure safety

of the system. Then the durability of the

machine must be guaranteed, and fnally the

purchasing and running costs of the motor

must be calculated and optimized.

Pneumatic motors are available in

diverse design options. Their application and

the intended operating time are of great

importance when selecting the right basic

principles. An air vane motor is suitable for

regular running cycles. If you wish to run it non-

stop then you must consider the wear on the

vanes and the shorter maintenance intervals

this requires. In comparison, gear motors and

turbines are maintenance-free and therefore

better suited to continuous operation. In this

case the required speed must be considered.

Turbines and gear motors rotate in upper

speed ranges at approximately 140,000 rpm.

Vane motors are available which rotate at

very low speeds, e.g., 1 rpm. Oil-free operation

is also an option for all three drive principles. A

slight loss of power must be taken into account

with oil-free operation of a vane motor.

Different materials

The second step examines the motor’s

construction material. If operating in a dry

surrounding atmosphere and in normal

stationary production, an inexpensive air

motor made from cast iron will be suffcient.

Deprag offers a wide spectrum of low-priced

Basic Line motors. For installation in robots

and machines there are a variety of grinding

motors, drilling motors and milling motors

available which are distinguished by their low

weight and compact size.

For use in the food industry, pneumatic

motors must be able to withstand cleaning

agents and steam. The Deprag Advanced Line

motors with external parts made from stainless

steel are additionally sealed and lubricated

with food industry standard USDA-H1 grease.

Pneumatic drives can even be operated

underwater. In this case it is essential to

determine the water depth required. If the

motors must be started underwater they

can be used up to a depth of 5 metres. If

the motors are started on the surface and

then submerged, they can be used in a

depth of up to 20 metres without damaging

the motor. If the motor must be sterilizable,

as requirements demand in some medical

technology applications, then it can be

equipped with special vanes. There are many

examples here of why it is important to speak

to the air motor manufacturers in advance

about your application and to describe it in

as much detail as possible.

Motor power

The next step is the calculation of the

theoretical motor power. Motors which are

designed for use in only one rotational

direction are more effcient than reversible

motors. When determining the rotational

direction, the pneumatic expert looks towards

the motor shaft from the air inlet. This is the

other way around for electric motors, where

the rotational direction is specifed by looking

at the motor spindle.

First the required working point of the motor

is determined: which nominal torque and

speed under load do you want to reach? The

most economic use of the motor (least wear

and least air consumption) is attained by

running close to the nominal speed. If you look

at the characteristic curve of an air motor, it

shows that it reaches its maximum torque just

before standstill (around twice the specifed

nominal torque).

At the nominal speed the air motor reaches

maximum power. With the formula nominal

torque times working speed (nominal speed)

divided by 9550 you can fnd the theoretically

required power in kW.

In manufacturers’ catalogues, performance

data is based on varied operating pressures.

At Deprag this is 6 bar. If the application only

has 5 bar directly at the motor then the motor

loses 23 per cent of its power. If there is only 4

bar available then motor power is reduced by

45 per cent. A differing operating pressure is

so decisive that it must be taken into account

at the start of the design phase using the

adjustment table, in order to avoid nasty

surprises.

Next, the air supply volume – which is

specifed by the air consumption in the

manufacturers’ details – must be ensured. Every

reduction in the width of the opening, whether

on the feed hose itself or due to connection

parts, flters, oilers or the exhaust hose and

silencer all have an effect on the air volume.

Therefore Deprag recommends an exhaust air

throttle to its customers to regulate their speed.

Using a throttle on the supply air reduces the

speed of the motor but, at the same time, the

torque is reduced as well. Exhaust air throttles

can reduce the speed without great loss

Calculation of theoretical motor power

Credit: Deprag Schulz

1411PEI_22 22 11/10/14 9:47 AM

www.PowerEngineeringInt.com 23Power Engineering International November 2014

Motors and drives

of torque. The exhaust throttle means that

customers can better utilize the wider working

range which air motors provide.

The optimal lifespan and performance of

an air motor is reached with lubricated running

(1–2 drops of oil per 1 m³ air consumption).

Unlubricated operation can lead to a loss of

power of around 10–20 per cent.

Design integration

If the right motor with the required power has

been found, then the next step is to integrate

it into the design. Deprag provides various

spindle designs and individual fxing methods.

A complete solution is often better value

than seeking a gear solution separately.

Within the Deprag range there are numerous

air motors with integrated planetary gears,

spur gears and worms gears. If you require

additional safety then a holding brake can

be recommended. In the manufacturer’s

programme you can also fnd brake motors.

For use in potentially explosive environments,

there are also options with the required ATEX

certifcation. Integration is concluded with

the technical verifcation of the maximum

permissible axial and radial load on the drive

spindle of the air motor.

Air motors are powerful, durable and

robust. Adherence to the framework

conditions determined during the design

phase and compliance with the instruction

manual will ensure the longest possible life of

the drive. These conditions include adhering

to the recommended air quality, lubricated

operation, maintenance intervals, a maximum

length of the feed hose of three metres and

suffcient opening widths of the feed hose and

connection parts.

Considering costs

Finally, the purchase price is the predominant

consideration in the acquisition of a new

drive system. But the designer should also

remember running expenses and consider the

operating costs and price for maintenance

and servicing. When planning and selecting

a new system, the question must be asked:

how readily available are replacement parts

and what are their prices? Maintenance and

repair service quotations ensure that this is

calculable. Deprag’s Basic Line air motors

are particularly maintenance-friendly. The

patented vane exchange system enables

an air motor’s vanes to be quickly replaced

in situ using a key and tweezers. Operating

costs are determined by the air consumption.

The right choice of motor sets the course for

low running costs. The closer the motor runs to

nominal speed (50 per cent of the idle speed),

the more effciently the air is used.

Deprag Schulz has been using compressed

air as a working medium for many decades.

Deprag’s standard programme offers a wide

range of options and, from this modular

system, individual drive solutions for the

required application can be developed and

produced at an attractive price-performance

ratio. Around 85 per cent of the frm’s projects

in the feld of air motors are special solutions

which have been quickly and simply realized

from its standard programme.

Dagmar Dübbelde is Product Manager, Air

Motors at Deprag Schulz

Visit www.PowerEngineeringInt.com for more informationi

ONLY ONEBOLTING SYSTEM

IMPROVESSAFETY, QUALITY,

& SCHEDULEFOR GAS TURBINE

MAINTENANCE

1411PEI_23 23 11/10/14 9:47 AM

Risks of unwanted combustion

– potentially causing injury,

damage and/or downtime

– occur everywhere coal is

handled, processed or stored.

Safe coal handling practices

are designed to ensure that the fuel remains

intact throughout its journey from the mine

until the point at which it is ignited in the boiler.

It takes as little as 1.4 kg of pulverized

coal in 28.3 m3 of air to form an explosive

mixture. Since a large boiler burns 45.4 kg or

more of coal per second, the safe burning of

pulverized coal necessitates strict adherence

to planned operating sequences.

All coals oxidize during storage, but sub-

bituminous coals are especially prone to self-

ignition. The increasing use of sub-bituminous

coals throughout Asia has increased the risks

of silo fres.

Good operating procedures are designed

to ensure that coal is used before it has time to

self-ignite, and many operators use a nitrogen

blanket to minimize the scope for oxidation.

Even with appropriate precautions, silo fres

can still occur and appropriate monitoring is

needed to prevent oxidation from developing

into a silo fre.

The greatest risk of fre occurs when the

mill is shut down under load, as this leaves a

large amount of pulverized fuel inside a hot

mill. The large surface area of the pulverized

coal and the high temperature inside the mill

lead to rapid oxidation of the coal. This results

in further heat buildup and the potential for a

fre. If the mill is restarted without frst removing

the hot coal, an explosion can occur when

particles are suspended and exposed to

the air.

Even in routine mill shutdowns, there is a

danger that any residual coal left within the

mill will oxidize, and may explode as the mill

is restarted. To prevent a coal fre, the mills can

be made inert with a steam deluge when an

unexpected shutdown occurs, or when there

is a high risk of a coal fre.

Several methods are available to detect

the presence of oxidization within the mill or

silo:

lThermocouples are widely used to detect

the heat buildup from oxidation or an early-

stage mill fre, but they have limited sensitivity

and discrete sensors have diffculty

monitoring the whole volume of the mill. It

also takes time for suffcient heat to build up

within the mill to give a detectable increase

in temperature. Experience shows that

thermocouples do not provide a reliable

indication that a hazardous condition is

developing.

Coal plant safety

Equipment selection and operating criteria are vital for reducing the risk of fre in coal storage silos and mills, writes Derek Stuart of Ametek

Strengthening safety in mills and silos

Hoosier Energy’s Merom Generating Station in Indiana, US

Credit: Ametek Land

24 Power Engineering International November 2014 www.PowerEngineeringInt.com

1411PEI_24 24 11/10/14 9:47 AM

The single-phase enclosed HB3-80 generator

switchgear provides for sustainable and reliable power

supply in power plant technology.

The HB3-80 is the first generator switchgear worldwide

with vacuum generator circuit-breakers for ratings up to

10,000 A with natural cooling, and a switching capacity of

80 kA type-tested according to the IEEEC37.013 standard.

Thanks to its single-phase enclosure if offers maximum

operational and personal safety, as short circuits between

phases are excluded.

www.siemens.com/generatorswitchgear

Totally Integrated Power

Applications:

Power plant generating units up to 160 MW or 250 MW,

depending on the on the type of power plant and

operating voltage

Indoor and outdoor installation

Advantages:

Optimum operational and personal safety

Sustainable and environmentally friendly

vacuum technology

Minimum installation and maintenance costs

High cost-efficiency and service continuity

HB3-80 generator switchgearTrend-setting with vacuum technology

IC1

00

0-E

32

0-F

23

6-X

-76

00

For more information, enter 12 at pei.hotims.com

1411PEI_25 25 11/10/14 9:47 AM

26 www.PowerEngineeringInt.comPower Engineering International November 2014

Coal plant safety

lCarbon monoxide (CO) gas detection offers

a fast and sensitive means to detect the

presence of oxidizing coal, as the oxidation

inevitably produces large amounts of CO.

The most important reasons to choose CO

measurement for this application are the

availability of sensitive CO sensors able

to detect a few parts per million (ppm)

of CO, and the ability to sample a large

portion of the mill using a probe mounted

at the classifer outlet. CO monitoring is fast,

sensitive, specifc and can be calibrated to

determine alarm levels that reliably identify

a potentially hazardous condition while

minimizing the occurrence of false alarms.

•Once a fre has started, optical detectors

respond to sparks and fames within the mill.

By the time fames are visible, it is too late to

take preventative actions because the mill is

already in a very hazardous condition.

One of the biggest challenges in

confguring a Millwatch system is the

determination of suitable alarm levels. A

carbon monoxide concentration greater than

250 ppm can be seen during mill startup, but

in normal operation the CO concentration is

in the region of 10 ppm.

Millwatch analyzers offer two independent

alarm points, so alarm levels were set at

300 ppm during startup and 50 ppm in

normal operation. Although the startup alarm

seemed robust, there were occasional spikes

above 50 ppm CO in normal operation, so the

alarm level was increased several times with a

fnal fgure of 125 ppm. This avoided nuisance

alarms, while providing good sensitivity and

response to abnormal operating condition

when the mill may need to be inerted.

Monitoring in China and the US

HouShiPower is a 4200 MW electricity

generating plant in China’s Fujian province,

operated by the Huayang Group. It supplies

electricity to the city of ZhangZhou and the

surrounding area.

There are seven electricity generating

units at the site, each of which is rated for

600 MW. In 2011, the plant operators decided

to add CO monitors to the fve coal mills in Unit

1, supplementing their existing temperature

and fre sensors. They determined that

Ametek Land’s Millwatch analyzers were best

suited to the task. The analyzers have a long

track record, with hundreds of installations

worldwide, and include a number of desirable

features:

lRugged sample probes with automatic

blowback to maintain a good sample fow;

lAutomatic calibration verifes correct

operation of the analyzers, confrming that

they respond correctly to CO;

lContinuous measurement of each sample

point, with no multiplexing and response

time less than 60 seconds.

This last feature is especially important as a

hazardous condition can develop within a few

minutes, and a multiplexed system sampling

six measurement points will typically sample

each point only once every 10–15 minutes.

The system proved its value in 2013 when

the Millwatch system showed rapidly rising CO

levels in the outlet of one of the coal mills. It

would have taken at least 15 minutes for the

temperature and fre detection systems to

respond and show an indication of a problem,

so the Millwatch analyzers allowed corrective

action to be taken signifcantly earlier than

would otherwise have been possible.

Hoosier Energy’s Merom Generating Station

in Indiana, US, is a coal-fred baseload plant

with two 535 MW generating units. It went into

commercial operation in 1982 and provides

power to electric distribution co-operatives

in the midwestern US. At full load it uses

10,000 tonnes of coal per day, with the supply

coming from mines by road and rail.

Hoosier Energy has a strong commitment

to safety and maintains a robust safety

programme, endeavouring to operate with

the utmost regard for the health and safety of

its employees and the public.

Each generating unit at Merom Station

has three Riley Power double-ended ball tube

mills. The mills can each provide 65 tonnes per

hour of pulverized coal to the boiler, a total of

195 tonnes per hour per boiler. The boilers at

Merom station burn 54 kg of coal per second.

Because the ball-tube mills have outlets

at each end with a classifer on each outlet,

two sample points were needed on each

mill. For enhanced reliability, a redundant

confguration was chosen with two sample

points on each classifer, giving four samples

per mill. With three mills per generating unit,

a total of 12 sample points were needed

for each unit or six twin-stream analyzers.

Redundant measurements reduce the

likelihood of a nuisance alarm, as a high CO

Inside view of Millwatch analyzer

Credit: Ametek Land

1411PEI_26 26 11/10/14 9:47 AM

www.PowerEngineeringInt.com 27Power Engineering International November 2014

Coal plant safety

measurement is unlikely to be detected on

one coal pipe while the others continue to

show normal readings.

The initial proposal was to mount the

sample probes directly on the classifers.

Even though the inside of the classifer is

a hazardous area, the sample probes are

simple devices with no electrical connection

and so no special precautions were needed.

Although this would have provided a

representative sample, the probes have an

abrasion shield which prevents the stainless

steel flter from being damaged by the high

concentration of coal dust. An installation

location at the classifer outlet was preferred,

since this allowed the abrasion shield to face

the fow of coal dust and protect the flter.

Blowback controllers were installed close

to the classifers, but outside the hazardous

area.

Along with the CO monitors, an in situ

oxygen probe was installed on each classifer,

to determine the oxygen concentration while

the mills are steam-inerted. The CO analyzers

were installed at the same level as the

classifers. This meant that the sample lines

could be kept short and the response time

minimized. The chosen location also gave

easy access for maintenance. Commissioning

took place during an outage in May 2011.

In the three years since the Millwatch

analyzers were installed at Merom Station,

there have been a number of high-CO

alarms, but no mill explosions -- an impressive

achievement for a baseload station. During

that time, the Millwatch analyzers have proven

to be reliable, requiring no more than routine

maintenance and providing enhanced

safety.

On 8 December 2013, the Millwatch

analyzers demonstrated their value. With Unit

2 running at full load, one of the mills tripped

and the operators observed a rapid increase

in CO readings even though there was no

indication of a temperature rise. Within a few

minutes, the CO level was above the alarm

threshold, and the operators made the

decision to activate the deluge system. The

boiler continued to operate using coal from

the remaining mills, with output dropping to

60 per cent of its rated value.

The CO level in the affected mill started

dropping after 15 minutes, and within

45 minutes it was below 10 ppm. The mill

was restarted two hours after the high CO

alarm was detected, and was returned to full

operation in three and a half hours.

The Millwatch CO analyzers detected a

potentially dangerous condition and allowed

it to be dealt with quickly with no damage to

plant or personnel.

In conclusion, CO monitoring provides a

rapid and reliable method for detection of

potentially dangerous coal oxidation within a

mill so that action can be taken to reduce the

risk of a fre or explosion.

At both HouShiPower Plant and Hoosier

Energy Merom Station, Millwatch analyzers

from Ametek Land have provided good

reliability and a high level of safety coverage

with no explosions in the mill since they were

installed more than three years ago.

Derek Stuart is Product Manager at Ametek

Land, based in Pittsburgh, Pennsylvania, US

Visit www.PowerEngineeringInt.com

for more information i

Customized special control valves

For the energy producing and consuming industry

WELLAND & TUXHORN AG

A R M A T U R E N - U N D M A S C H I N E N F A B R I K

Gütersloher Straße 257 | D-33649 Bielefeld | Tel. +49 (0)521 9418-0 | Fax. +49 (0)521 9418-170, -156 | www.welland-tuxhorn.de | info@welland-tuxhorn.de

• HP-, IP- and LP-

turbine–bypass–systems

• turbine emergency stop valves

• turbine control valves

• steam conditioning valves

• feedwater control valves

• minimum flow control valves

• cooling water injection valves

• boiler start up valves

• boiler blow down valves

• desuperheater valves

• hydraulic actuating systems

THE AMERICAN SOCIETY

OF MECHANICAL ENGINEERS

For more information, enter 13 at pei.hotims.com

1411PEI_27 27 11/10/14 9:47 AM

Combustible materials,

dust and debris, and

voluminous areas make

fre detection for power

stations challenging.

Solutions must be

sensitive to danger and raise alerts early, but

must not be prone to costly false alarms. This

all amounts to another serious problem the

power station safety offcer or facility manager

has to face.

In July of this year, the UK’s Ferrybridge

power plant was affected by a fre widely

reported in the media.When the nationally-

broadcast images had begun to fade from

memory, the cost to Ferrybridge’s owner, SSE,

began to be calculated.

RBC Capital analysts estimated

a loss in earnings of around

£35 million ($56 million). SSE will also have

to factor in the cost of repairing the facilities

(although insurance will cover much of the

losses) and the transactional costs of buying

back forward-contracted power that will now

need to be sourced from elsewhere.

Just weeks ago Didcot B Power Station, also

in the UK, suffered a major fre in its cooling

towers. More than 25 fre appliances from

as far as 30 miles away were called to the

1360 MW gas-fred plant, which is operated by

RWE npower.

While the full costs of the damage are

still being calculated, the impact on the UK’s

power needs has generated much debate.

Peter Atherton, energy analyst at Liberum

Capital, stated that the risk of blackouts this

winter was now far higher due to the UK’s

“meagre capacity” to absorb unexpected

events.

As developed countries fnd power

disruption an unacceptable situation, the

extra capacity in the system should see the

UK with the energy supply it needs over winter,

providing that other major fres and incidents

to power generation are avoided. But for a

single power plant to make the possibility

of power shortages a reality shows the

importance of protecting these critical assets.

The challenges

The sheer size of power plants makes fre

detection a challenge: the huge ground

area occupied, the ceilings often as high as

20 metres and the voluminous areas that must

be monitored.

This presents diffculties in terms of the time

it takes for smoke to reach detectors – and it

may not reach them at all owing to smoke

stratifcation. We can also factor in the need to

provide a system that can cover large areas

effectively – no easy task.

Turbines also present a very industry-

specifc issue: fre is initially hard to detect as

the shell can obscure and contain fames for

some time, impeding early detection.

Power generation environments are known

for their high levels of dirt, grease, dust and oil.

This, of course, means that any fre detection

system needs regular maintenance.

Moreover, the combustible nature of oil,

gas, coal and renewable waste makes plants

vulnerable, and with the debris that can be

kicked up there is the inherent danger of

numerous false alarms. A balance needs to

be struck between the required sensitivity and

false alarms, which some fre services are now

demanding visual verifcation for commercial

properties before attending, while some levy

fnes for being called out for false alarms.

If suppressants are released, then for

voluminous areas the cost can be substantial,

certainly well in excess of £100,000 for many

sites. The attendant environmental impact

such as wash-off running into water supplies

also needs to be considered.

Fire detection technology

Visual Smoke Detection (VSD), Infra-red (IR)

and Aspirating Smoke Detectors (ASD) are the

principal options for power station operators.

Each has advantages and drawbacks.

VSD uses motion system technology to

identify and analyse the behaviour of smoke

patterns and fames Visual monitoring at the

point of fre danger is particularly suited to

large areas and across distances.

Fire detection

As the UK suffers the second major blaze at a power plant in three months, Ali Aleali of FireVu explains the fre detection challenges and solutions

facing power plant operators

Hot topic

The effort involved in fre detection is justifed by the need to protect valuable power assetsCredit: Dreamstime

28 Power Engineering International November 2014 www.PowerEngineeringInt.com

1411PEI_28 28 11/10/14 9:47 AM

www.PowerEngineeringInt.com 29Power Engineering International November 2014

Fire detection

Footage can offer visual verifcation (usually done on-site) and

large area monitoring, and can direct the use of fre suppressants and

emergency services.

Temperature sensing capabilities can be incorporated within the

system, the latter being a new innovation in the market.

Infrared converts radiant energy in the IR into a measurable form.

Detecting IR energy emitted by objects takes away reliance on visible

light, so obscured conditions should not affect its effectiveness although

thick smoke is an issue. Oil and grease can also be problematic.

IR gives much of the VSD solution, however the latter offers

accompanying video, which provides better situational awareness in

the event of a fre. It also helps determine the most appropriate action

that should be taken, triggering an overall suppression system.

ASD is a highly sensitive technology. It can detect smoke before it

is visible to the human eye, which is particularly valuable where a fre

develops in obscured or diffcult-to-access locations or environments

containing dangerous and toxic substances. Yet the sensitivity to

distinguish between smoke and dust in early-stage fres can be

problematic in some facilities, although improvements are being

introduced. Moreover, it requires that smoke hits detectors, which can

be challenging if smoke stratifcation is a possibility.

Ferrybridge and now Didcot remind us of the costs of fre in power

generation environments. Safety professionals must analyse their

requirements against the solutions available, be it VSD, ASD, IR or another

system. Fire detection for power stations requires planning, frequent

maintenance and continual assessment, but the effort is justifed by the

need to protect these high-value assets.

Ali Aleali is Business Development Manager at FireVu, which

works with power plants across the UK and Ireland. Please visit

www.frevu.co.uk

Visit www.PowerEngineeringInt.com for more informationi

VSD operator’s dashboard: Users can segment the video to concentrate on

specifc areas of greater fre risk

Credit: FireVu

HIGH PERFORMANCE

Electric actuators for the

power plant industry

Reliable, powerful, precise control. AUMA

offer a large portfolio of actuator and

gearbox type ranges.

■ Automating all types of

industrial valves

■ Standardised interface for

various site control systems

■ Plant Asset Management functions

■ Service

worldwide

Discover

our solutions

for the

power plant

industry

www.auma.com

For more information, enter 14 at pei.hotims.com

1411PEI_29 29 11/10/14 9:47 AM

Since the 1920s, steam generator

owners have used particulate

removal technologies such as

cyclones, fabric flters, or dry or

wet electrostatic precipitators

(ESPs) to collect fue gas particles

such as fy ash.

Today utilities expect ESPs to effciently

remove very fne particulates (e.g., PM10) and

often rely on a wet fue gas desulphurization

(FGD) system to remove smaller and harder-to-

capture sub-micron particulates (e.g., PM2.5,

mercury, and other hazardous emissions)

as a co-beneft. Experience has shown that

problems often occur when a FGD system is

added without a concurrent ESP performance

upgrade.

ESP operation, in principle, is very

straightforward. Particles to be removed from

the gas stream are charged by a series of

high-voltage electric discharge electrodes

to produce negatively charged ions (corona

discharge) that charge the particles in the

fue gas, providing the driving force for moving

particles to the collecting plates.

Next, plates stationed parallel and on each

side of the gas stream are grounded in order

to attract and accumulate the negatively

charged particles in cake-like layers on the

plate surface. Finally, the particulate matter

is removed from the plates by mechanical

rappers causing the material to fall into

collection hoppers from which it is disposed

or recycled. The ESP removal effciency is

highly dependent on the voltage differential

between the discharge electrode (Eo) and the

collection plate (Ep). The typical ESP operates

at a voltage in the range of 30 kV and 100 kV.

The typical ESP will have multiple discharge

electrodes between each set of collecting

plates and multiple sets of collecting plates in

a single ‘feld’ in the direction of gas fow. Each

feld acts as an independent precipitator.

Multiple felds may be added in series to

improve particle removal effciency with most

plants using three or more felds.

Retroftting

Poor electrostatic precipitator performance can often be traced to an underperforming high voltage power supply. Retroftting with a high frequency switch mode power supply can quickly reduce particulate emissions and often improve the performance of a downstream wet fue gas desulphurization system, writes Jason Horn

Fly ash has been collected by particulate removal technologies since the 1920s

Credit: Pittsburgh Mineral & Environmental Technology

30 Power Engineering International November 2014 www.PowerEngineeringInt.com

A fresh perceptionof ESP

1411PEI_30 30 11/10/14 9:48 AM

www.PowerEngineeringInt.com 31Power Engineering International November 2014

Retroftting

Some plants use up to 12 felds in order to achieve collection

effciencies greater than 99 per cent. In most utility applications, each feld

is also electrically divided into separate compartments or ‘lanes’ to further

optimize particulate removal effciency, primarily due to temperature

and fow rate gradients across the fue gas entering the ESP. The ESP has

been chosen as the PM removal device in over 90 per cent of utility

applications due to its low pressure drop (usually 0.5–1.0 inch water

column), which translates into less auxiliary fan power.

The particle removal effectiveness of an ESP is largely based upon

the resistivity of the particles (the ability of a particle to hold a charge),

the gas fow properties, and the quality and strength of the electric feld

produced between the electrodes and collection plates. Also, a fuel

change often changes the resistivity of the particles in the fue gas.

The recent US Mercury and Air Toxics Standards (MATS) also place

limits on mercury and acid gas limits on boilers that may require adding

activated carbon injection for mercury removal and/or dry sorbent

injection to remove acid gases. Adding activated carbon or dry sorbent

to the gas stream may change the particle resistivity and therefore

the effciency of ESP operation. Other changes in the fue gas, such

as volumetric fow rate, moisture content, chemical composition, and

temperature can also adversely impact the particle collection effciency

of an ESP.

There are a number of upgrade alternatives available to those

needing to increase the particulate removal capacity or those

experiencing an underperforming ESP. Options available to the end

user are increase collecting surface area, improving the fow distribution

entering the ESP, and upgrading or replacing the collection plates or

discharge electrodes. Each of these options requires extensive physical

changes to each stage of the ESP and all require an extended unit

outage and signifcant cost.

The conventional power supply system for an ESP consists of the

transformer-rectifer (TR) set current-limiting reactor (CLR), and silicone

controlled rectifer (SCR) that produce the high voltage power source

for the discharge electrodes. The TR set is a high voltage transformer and

rectifer that converts single phase AC power to single-phase DC power

with approximately 30 per cent ripple in the output voltage waveform

due to 50/60 Hz operating frequency.

The CLR provides current limiting during transient overload (sparking)

conditions. The SCR regulates the voltage into the TR set to adjust the

output voltage and current to the ESP. Separate conventional power

systems are used on each ESP stage (sometimes each lane in a feld) in

order to optimize individual feld performance.

Anatomy of the switch mode power supply

Often a quicker, less intrusive and more cost-effective solution to improve

ESP performance is replacing the conventional power supply system

with a high frequency switch mode power supply (SMPS) that converts

50/60-Hz power to low ripple DC with output waveform ripple below 3

per cent.

The reduced ripple in the output voltage allows the SMPS

to produce a higher average output voltage (Eo), which in

turn produces higher collection effciency. The typical voltage

output from the SMPS – usually determined by ESP plate spacing,

discharge electrode type and particle resistivity – ranges from

50 kV to 120 kV with improved spark handling. The SMPS also has a faster

spark and arc response time – microseconds instead of milliseconds

FROMENGINEERINGANALYSIS TO ADVANCED NDE,LOOK TOSTRUCTURAL INTEGRITY

( 8 7 7 - 4 S I - P O W E R )8 7 7 - 4 7 4 - 7 6 9 3

Scan the QR Code for more information

www.structint.com/power-eng-int

We Connect the DotsOver the past 30 years, Structural Integrity has built a team of over

200 industry experts providing comprehensive solutions to the energy industry. We connect the dots from problem to resolution, from regulations to compliance, from nondestructive examination, to engineered solutions, even custom equipment.

You can look to us for our:• Knowledge of power plants, codes, and how

things work.• Extensive experience and leadership.• High quality, hard work, and responsiveness.

Call us today and we’ll connect the dots for you.

For more information, enter 15 at pei.hotims.com

1411PEI_31 31 11/10/14 9:48 AM

32 www.PowerEngineeringInt.comPower Engineering International November 2014

Retroftting

– that reduces power dissipated in sparks

and arcs and reduces wear on power feed

components and ESP internals.

The SMPS upgrade option has two principal

benefts that are dependent on how the unit

is operated. The frst beneft is to improve ESP

collection effciency when less particulate

emissions are desired. The SMPS puts more

power (increased Eo) into the ESP resulting in

higher collection effciency.

The second beneft for plant owners is for

a unit where less ESP auxiliary power use is

desired in order to either improve unit heat

rate or increase sellable power to the grid. With

this option, the SMPS replaces the ineffcient

conventional power systems used on an

ESP operating with acceptable collection

effciency by limiting the power output to

that of the TR and CLR it replaces. The SMPS

operates at >90 per cent power effciency

compared to the TR, which generally operates

at <60 per cent. For the same power input

into the ESP (and the same ESP collection

effciency), SMPS can reduce auxiliary power

use by 30 per cent.

ModuPower SMPS systems have also been

used in a variety of unique applications, as the

following three case studies will illustrate.

Case studies

For example, at AES Gener’s 135 MW coal-fred

Norgener Power Station, located in Tocopilla,

Chile, its 1990s vintage ESP met air emissions

standards when built. New regulations that

went into effect this year reduced the level

of permitted particulates from 211 mg/Nm3

(98 per cent removal rate) to 50 mg/Nm3

(99.95 per cent removal rate). The reduced

emissions limits would require a unit derate in

order to continue operating.

Norgener replaced three of the four

conventional power supply systems on

each unit with Stock Equipment Company’s

ModuPower SMPS, which allowed Norgener to

increase generation to full load on each unit

while maintaining particulate emissions below

the new particulate discharge limits.

A 640 MW supercritical utility boiler located

in Ohio was reconfgured with a wet FGD

downstream of its existing four-lane/12-feld

ESP. It was assumed during design that the

new wet FGD would capture particulates not

removed by the ESP, so no enhancements to

the ESP were made as part of the FGD retroft

project (see Figure 1).

However, shortly after the FGD was

commissioned, the plant determined that

excessive particulates were entering the FGD

and fouling pumps, pump linings, and piping.

Also, the ash contamination reduced the

quality of the gypsum byproduct from the

FGD, negating its market value. Instead of a

positive cash fow from the sale of the gypsum,

the utility must pay the cost of landflling the

waste product.

During the frst year, authorities allowed

the plant to ‘bypass’ the FGD system when

it required monthly maintenance to repair

damage caused by excess particulate

emissions from the ESP.

However, after the frst year of operation a

monthly unit outage was required to perform

FGD maintenance, an untenable situation for

a baseload unit. The site was limited in size so

adding felds to the ESP wasn’t an option.

Stock Equipment Company was asked

to evaluate options for repowering the ESP in

order to reduce particulate emissions entering

the wet FGD.

The solution was to add four

ModuPower SMPS systems of 60 kW

(83 kV/1080 mA) for each lane in the second

and third felds and four 90 kW (83 kV/

1080 mA) systems for each lane in the sixth

feld. This approach allowed the original inlet

feld TR sets to perform the relatively easy chore

of removing large, friendly particles in the

front of the ESP, and to use ModuPower SMPS

systems to do more diffcult removal work in

the center of the ESP.

The ESP represented a special challenge

in that access to its roof was diffcult, and

there was little space available in which to

locate the ModuPower SMPS equipment.

Also, another SMPS brand previously installed

had failed to operate reliably in the high

temperature and dirty environment within the

ESP weather enclosure.

With this in mind, Stock Equipment worked

with the customer to remote-mount the

ModuPower units in a pre-wired modular

control room that was located on the ground

at the base of the ESP. The entire system was

delivered as two structures, each containing

six of the 12 ModuPower units provided. The

plant was required to only connect power to

the switchgear provided in each control room

and run high voltage cable to the roof of

the ESP.

All the installation work was completed with

the unit in operation, with only a short outage

required to make the fnal electrical tie-in to

the ESP. This unique remote SMPS installation

provided by Stock Equipment enhanced the

project’s ROI signifcantly.

The ModuPower SMPS installation

produced an over 100% increase in power

sent to the ESP, from 464 kW to 1052 kW. With

the exception of the inlet felds that are

exposed to the highest dust burden, all felds

are operating at the nameplate current limit

rating of both the ModuPower units and the

original TR sets.

More importantly, the repowered ESP has

eliminated outages caused by excessive

particulates entering the FGD and restored

the quality of the gypsum by-product. The

plant has since installed an additional 12

Figure 1: Ohio plant ESP roof with ModuPower ground switches installed on the insulator compartment

Credit: Stock Equipment Company

1411PEI_32 32 11/10/14 9:48 AM

For more information, enter 16 at pei.hotims.com

1411PEI_33 33 11/10/14 9:48 AM

34 www.PowerEngineeringInt.comPower Engineering International November 2014

Retroftting

ModuPower SMPS systems on felds 1, 4, and 6

of the same unit.

A 670 MW supercritical utility boiler located

in West Virginia, US is confgured with a wet

FGD after its ESP (see Figure 2). The ESP is

confgured as four felds deep, eight lanes

wide, with each feld using weighted wires on

a nine-inch gas passage spacing. Though the

ESP as designed did not perform effectively,

it did not experience excess particulate

emissions because of the downstream wet

FGD. However, the two induced draft (ID) fans

that are positioned between the ESP outlet

and the FGD inlet were suffering signifcant

mechanical erosion and producing

increased vibration as a result of excess fy ash

leaving the ESP. Quarterly fan cleaning, repair,

and rebalancing, plus the associated cost of

a four- to fve-day outage cost millions, and

easily exceeded the cost of an ESP upgrade.

Plant management considered a number

of permanent repair options including

expanding the ESP, but the cost was prohibitive

and the site was space-constrained. The best

option was to upgrade the ESPs to reduce the

amount of particulate emissions entering the

ID fans.

The plant frst rebuilt all the ESP boxes to

11.5-inch spacing and retroftted the ESP

with rigid discharge electrodes in an effort

to improve the particle removal effciency.

However, the existing 45 kV TR sets ran out of

secondary voltage and fan wear worsened.

The plant next tried to replace the existing TR

sets with a higher-power design but without

changing the kVA rating of the units. The new

TR set produced higher voltage (kV) and lower

current (mA) but produced the same primary

current rating. This approach saved the cost

of changing out the CLRs, power cables

and other equipment inside the automatic

voltage control cabinet. However, the new

TR equipment hit its secondary current limit

before reaching signifcantly higher voltage

levels (Eo) and fan erosion continued.

The plant eventually decided to upgrade

its ESP with an SMPS, and ModuPower units

from Stock Equipment were selected. Eight

90 kW (83 kV/1080 mA) units replaced the

newer 36 kW TR systems (65 kV/550 mA) on

the inlet feld of the ESP where the majority of

the particulate removal takes place.

The site arrangement required the

ModuPower equipment to be installed away

from the roof of the ESP and required the

use of a high voltage cable to bring the DC

power to the ESP. In addition, the ModuPower

units were installed and commissioned one

at a time while the boiler and ESP remained

online, thereby avoiding one or more costly

plant outages. The original TR sets were

disconnected but left in place as backup

systems should the need arise.

ModuPower installation raised the power

(kW) not only in the inlet feld but also

across the entire ESP. The improved collection

effciency at the inlet of the ESP allowed the

downstream conventional TR sets to perform

at a higher effciency as well. Power provided

to the ESP increased 204 kW and the current

increased by 3114 mA, equivalent to the

power input produced by fve TR systems.

A year after the installation was completed

the unit has not experienced a single FD

fan erosion- or vibration-related outage. The

utility saved over three times the cost of the

ModuPower units in the frst year of operation.

The utility has since purchased ModuPower

units for the remaining three felds on this unit,

and all four felds at the other two 670 MW

units located at this plant.

Upgrading the particle removal effciency

of existing ESPs is inevitable as new air quality

rules take effect. However, a ModuPower

upgrade can also be a good business

decision because it can minimize ID fan

erosion and improve the performance of a

downstream wet FGD, thereby reducing the

ash content in the gypsum byproduct so it

can be recycled rather than landflled. For

ESPs already meeting air quality regulations,

an SMPS upgrade can reduce auxiliary power

requirements and pay for itself in short order.

Customers and ESP OEMs around the world

are standardizing on SMPS technology for ESP

upgrades and new precipitator installations

in place of the conventional power supply

systems.

Jason Horn is director, environmental controls

for Stock Equipment Company (www.

stockequipment.com)

Visit www.PowerEngineeringInt.com for more informationi

Figure 2: A 90 kW ModuPower was installed

at a West Virginia coal-fred plant

Credit: Stock Equipment Company

AES Norgener ESP with ModuPower ground switches installed on top of its ESP

Credit: AES Norgenere

1411PEI_34 34 11/10/14 9:48 AM

Coming in the January issue of Power Engineering

WORLD’S BIGGEST

AND BEST!

2015 Global Ranking of the Power Industry’s Leading Companies, certain to

become Power Engineering’s most-read content…ever.

Special advertising opportunities available.

For more information, go to www.power-eng.com/power-gen200.

For more information, enter 17 at pei.hotims.com

1411PEI_35 35 11/10/14 9:48 AM

Vacuum circuit-breakers

are used in most industrial

switchgear – with good

reason, since they have their

own particular strengths

in terms of installation,

operation and maintenance.

In the past, it was not possible to use

the potentials of the long-proven vacuum

technology for generator switching

applications. Today, however, the appropriate

technical solutions are available, which are

tailored to suit the special requirements of

power plants and power supply companies.

In power plants, generator switchgear

ensures reliable synchronization and

maximum operational safety. When installed

between a generator and transformer, it

synchronizes parameters such as frequency,

voltage and phase with the grid.

In the event of a short circuit in the

generator or transformer, the integrated circuit-

breaker immediately cuts the fow of electricity.

This protection averts consequential problems

that could compromise the operation of the

entire power plant.

Last but not least, the generator can

also be switched on and off in a matter of

milliseconds in response to the appropriate

command, enabling it to be connected to the

grid right on target. This function will become

more and more important in future as the

trend toward renewable energy sources and

Smart Grids leads to decentralized power

plants with multiple smaller generators.

Generator circuit-breakers are thus

assuming a wide range of functions relevant

to power plant operation. At the same time,

they have to be designed for high currents.

Besides safely breaking short-circuit

currents, a key requirement is to immediately

extinguish any short-circuit arcing in the circuit-

breaker. Until about 15 years ago, there was

only one suitable technical process to deal

with this: extinguishing the switching arc using

the isolating gas sulfur hexafuoride (SF6) in a

chamber flled with this gas.

This powerful technology has been

Switchgear

Technological developments now enable maximum normal and short-circuit currents to be interrupted using vacuum circuit-breakers, writes Nils Anger

Proven procedure offers a new alternative

Generator circuit-breaker switchgear in combination with steam turbines were installed

at a cogeneration combined-cycle power plant in Rayong, Thailand.

Credit: Siemens

36 Power Engineering International November 2014 www.PowerEngineeringInt.com

1411PEI_36 36 11/10/14 9:48 AM

Æ

July 14 -17, 2015 // Oregon Convention Center // Portland, OR, USA

www.hydroevent.com

Owned & Produced by:

#HydroVision

Presented by: Media Partners:

• REGISTER EARLY AND SAVE! •

Please visit www.hydroevent.com for more information.

SAVE US$150 AS A FULL CONFERENCE ATTENDEEWHEN YOU REGISTER BY JUNE 5.

For more information, enter 18 at pei.hotims.com

1411PEI_37 37 11/10/14 9:48 AM

38 www.PowerEngineeringInt.com

Switchgear

Power Engineering International November 2014

successfully used in the power industry

until now. More recent technological

developments, however, enable maximum

normal and short-circuit currents to be

interrupted using vacuum circuit-breakers.

This means that all switching duties in

a generator switchgear can be assumed

in their entirety by vacuum circuit-breakers.

Unlike gas-insulated circuit-breakers, vacuum

circuit-breakers interrupt the switching arc

in a high-vacuum interrupter. This is therefore

an especially environmentally friendly and

reliable procedure for generator switching

applications that is now available as an

alternative.

The characteristic benefts of vacuum

switching technology are:

High reliability – The use of vacuum circuit-

breakers guarantees a high level of personal

and operational safety. One reason is the

small number of moving parts in the arcing

chamber. One of the circuit-breaker contacts

is frmly attached to the housing while the

other is movable. With this setup, the metal

bellows enables the switching stroke and

creates the vacuum-tight connection to the

interrupter housing. The hermetically sealed

vacuum interrupters

are also independent

of environmental

infuences. Not the

least of the advantages

is that no oxidation

occurs in the vacuum,

which means the metal

surfaces remain clean,

ensuring a constantly low

contact resistance.

Easy to install – Vacuum generator

switchgear is a factory-assembled solution

that is tested before it leaves the factory. It can

be immediately integrated into the power

plant technology on site. With SF6-insulated

circuit-breakers, on the other hand, the gas is

extracted for transportation immediately after

manufacture, and the circuit-breakers are then

reflled with gas at the time of installation, using

a special tool. This means not only increased

expenses but also a need for further testing.

Cost-effcient – Vacuum switchgear scores

in terms of overall results. The installation and

operating benefts described above keep

costs comparatively low during the entire

operating time (i.e. total cost of ownership) in

the case of switchgear with vacuum circuit-

breakers.

Nils Anger is Director of Generator Breaker

Switchgear at Siemens

Visit www.PowerEngineeringInt.com for more information i

HB3-80 - A WORLD FIRST

The latest addition to Siemens’ product range

is its HB3-80 generator switchgear.

This enclosed single-phase unit is suitable

for power plant blocks of up to 160 MW or 250

MW, depending on the type of power plant

and the operating voltage.

HB3-80 is the world’s frst generator

switchgear with generator vacuum circuit-

breakers for currents of up to 10,000 A with

natural cooling and a type-tested switching

capacity of up to 80 kA in accordance with

IEEE C37.013.

The switchgear is also type-tested in

accordance with IEC 62721-200 and the

Draft Dual-Code Standard IEEE/IEC 62271-

37-13. It offers maximum operational safety

and a high level of personal safety, since the

single-phase enclosure rules out the risk of

short circuits between the phases.

The HB3-80 is constructed to be

compatible with other products established

on the market, from the perspective of

retroftting in particular. Rather like a plug-

and-play solution, it can be incorporated

or retroftted into the generator connections

with no additional engineering costs. The

fexible selection of pole-center distances

and diameters means that existing round

conductors (isolated-phase busbars, IPBs)

can still be used.

Further switchgear types round out the

portfolio to provide optimized customer

solutions for the demands of a constantly

developing market: The compact HB1, with

horizontal busbars, is designed for power

plants of up to 120 MW or 170 MW.

Its fexible connection concept,

comprising bus ducts, cables and solid-

insulated bars, offers a broad range of

applications. The HB1 is very adaptable to

customer-specifc requirements. The modular

VB1 offers even more fexibility for personalized

solutions. This property makes it especially

interesting for power plants operated with

multiple generators or feeders for auxiliary

supply, excitation, or brake disconnectors. It

is suitable for the range of ratings up to 140

MW and - considering the high requirements

in terms of switching capacity, space and

accessibility - for use in hydropower plants

and retroft projects. The centerpiece of all

of these systems is formed by the 3AH37 and

3AH38 vacuum circuit-breaker for generator

switching applications: The 3AH38 high

current and generator circuit-breaker is

already the standard for switching normal

currents of up to 4,000 A in many power

supply companies worldwide.

As one of the frst circuit-breakers for

short-circuit currents of 63 kA and 72 kA

on the world market, it was type-tested in

accordance with the criteria of generator

circuit-breaker standard C37.013. Its

counterpart for higher generator ratings is

the 3AH37. A world-leading vacuum circuit-

breaker, it can manage a constant normal

current of 6,300 A at up to 24 kV with natural

cooling. With forced cooling, normal currents

as high as 8,000 A are possible. Optimizing

the circuit-breakers for joint operation

enables them to be used in phase-enclosed

switchgear and in retroftting situations.

Maximum normal currents of 12,000 A with a

short-circuit breaking capacity of 80 kA and

up to 6,300 A at 90 kA can be achieved.

The HB3-80 is the frst generator switchgear in the

world equipped with a vacuum generator

circuit breaker for an IEEE standard C37.013

type-tested switching capacity of 80 kA

Credit: Siemens

1411PEI_38 38 11/10/14 9:48 AM

Conference & Exhibition

1 ñ 3 September 2015IMPACT Exhibition & Convention CentreBangkok, Thailand

ASEAN POWER WEEK3 DAYS // 3 EVENTS // 1 VENUE

CALL FOR PAPERSSUBMISSION DEADLINE:

MONDAY 29 DECEMBER 2014

Owned and produced by:

Æ

Presented by: www.aseanpowerweek.com

www.powergenasia.com

www.renewableenergyworld-asia.com

www.����������������.com

Supported by:

Covering every aspect of the power generation industry,

POWER-GEN Asia, Renewable Energy World Asia and the POWER-GEN Asia Financial Forum converge once more in 2015 to form ASEAN Power Week.

We invite you to submit abstracts for ASEAN Power Week on the following topics and share your knowledge, experience and ideas with technical and strategic decision-makers and strategists.

For the full list of topics and how to submit your abstract visit:

www.aseanpowerweek.com Power Professionals

7,600

Natural Gas

Wind Power Power Project

Financing

Managing Risk

On-site Power

Energy Storage

HydroSolarCoal

Reach over

For more information, enter 19 at pei.hotims.com

1411PEI_39 39 11/10/14 9:48 AM

Transmission & distribution

Real-time information provided by dynamic line rating technology can play a vital role in increasing the power-carrying capacity of existing overhead

line assets and reducing congestion writes Sandy Aivaliotis

Credit: Dreamstime

40 Power Engineering International November 2014 www.PowerEngineeringInt.com

Oncor is a regulated

electric transmission

and distribution service

provider operating

approximately 1500

circuits serving 10 million

customers across the US state of Texas.

This grid is subjected to signifcant variability

in demand. Oil and gas developments have

prompted rapid load growth in specifc areas,

while wind and coal have created changes in

generation. In addition to these larger trends,

weather and load create daily fuctuations in

pricing, further increasing the unpredictability

of the load on any particular line.

Utilities are unable to distribute enough

power to meet the demand, leading to

congestion. A few lines suffer from congestion

over sustained periods of time, with fnancial

implications ranging up to hundreds of

millions of dollars.

Over the three-year period monitored,

approximately 200 lines would experience

sporadic to chronic congestion under

contingency conditions. Since ERCOT (the

Electric Reliability Council of Texas) dispatches

the system to avoid contingency overloads,

these constraints account for approximately

$172 million in annual congestion costs, even

though during actual operation the lines

are seldom loaded to their limits. If Oncor

could utilize more of the latent capacity that

exists in every line, customer costs could be

reduced not only through access to lower

cost generation, but also a reduction in

transmission charges.

There is an obvious requirement for a

fexible solution capable of meeting the

uncertainty of transmission grid need. Yet,

since grid topologies must adjust constantly

to refect load growth and changes in the

nature of generation and transmission grid

enhancements, the demand on individual

transmission lines can be diffcult to anticipate.

It is possible that loads can appear

and disappear within the planning and

construction duration of a traditional upgrade.

Smart grid technologies such as Dynamic

Line Rating (DLR) are required to meet the

fast-changing line capacity requirements of

today’s grids.

During the cost-sharing Smart Grid

Demonstration Project (SGDP) with

the US Department of Energy, over

24 months Oncor operated 13 transmission

lines by integrating DLR directly into its Electric

Management System (EMS) and streaming

the DLR information to the Independent

System Operator’s (ISO) Security Constrained

Economic Dispatch (SCED). This innovative

combination of new and existing technologies

to fully automate and stream DLR allowed

the ISO and Oncor to utilize the actual real-

time transmission line capacity to enhance

asset optimization and optimize generation

dispatch, leading to reduced congestion,

increased reliability and heightened

wide-area system awareness (WASA). By

completely automating the process, Oncor

achieved this breakthrough without adding to

the workload of its grid operators in the system

control centre.

Assumption-based operation

Overhead conductors exhibit a certain level

of ‘sag’ when strung between their supporting

towers. This is determined by both the physical

characteristics of the conductor (related to

materials and design) and the conductor

temperature – as a conductor carries more

current it heats up and sags.

Transmission lines must be operated so

that the overhead line conductor maintains a

minimum clearance from the ground or other

objects allowed on the right-of-way to ensure

safe, reliable operation. This safe clearance

is determined by specifc parameters that

A new solution for

1411PEI_40 40 11/10/14 9:48 AM

Transmission & distribution

www.PowerEngineeringInt.com 41Power Engineering International November 2014

characterize the position of the conductor.

These parameters include:

lthe conductor properties;

lthe line loading (in Amps); and

lambient conditions along the transmission

line including the ambient temperature,

net solar impact on the conductor and

effective wind speed blowing across the

conductor.

The current fowing in the line causes it to

heat up due to resistive heating. The sun can

further heat the conductor while the ambient

temperature can either heat or cool it. By far

the most dominant variable comes from wind

which, when blowing over the conductor,

provides cooling.

The net heat balance between these

infuences effectively makes the conductor

a spatial thermometer. Each conductor has

a time constant associated with its mass –

meaning that the conductor temperature

does not change instantaneously in response

to a changing net heat balance; instead

there is a lag in response. The conductor

sag, tension and temperature are a uniquely

coupled system.

The majority of utilities have established

what is referred to as a Static Line Rating (SLR)

which represents the level of current loading

the conductor can carry while maintaining

the desired operating safety and clearance

criteria.

The SLR is established at a designated set

of ambient weather conditions defning the

ambient temperature, effective wind speed

and level of solar radiation. A very common

set of parameters for this is 40°C, 0.61 m/s

perpendicular wind and full solar radiation.

Some utilities use an Adjusted Ambient Rating

(AAR) that adjusts the rating to account for

the ambient temperature along the line.

In effect, the majority of overhead

transmission lines are operated according to a

set of assumptions that project their operating

temperature and therefore sag, rather than

measuring it. This lack of real-time information

results in lines operating at loads well below

their actual safe limit – or, in other words, there

is a signifcant level of unused spare capacity

that could help to address grid congestion

issues if it can be accessed.

Across the utility sector, some may use

“dynamic” to refer to any line ratings which

change throughout the day, such as when

ratings are adjusted for ambient temperature,

seasonal or day versus night. In the context of

this SGDP project, we are discussing Dynamic

Line Ratings (DLR) where the condition of the

conductor is directly monitored in real time

(i.e., continuously). Further, because we have

integrated the DLR rating automatically into

system telemetry for real-time operations, we

refer to the ratings as integrated Dynamic Line

Rating (iDLR).

Real-time DLR technology, such as Nexans’

CAT-1 system, utilizes sensors that monitor the

key conductor parameters and calculates

those that cannot be directly measured,

providing a calibrated basis to project

the impact of additional current on the

conductor’s average temperature. The goal is

to maximize the line rating for existing ambient

conditions.

DLR is intended to adjust the SLR to the

rating appropriate for the real-time ambient

weather conditions. Ambient temperature

and solar radiation are relatively stable over

distance, but they have a very modest impact

on the ratings compared to the wind blowing

across the conductor. However, wind exhibits

considerable spatial variability and can vary

almost metre by metre along the span.

Fortunately, DLR technology can capture

that spatial variability and determine the

average effective wind speed on the entire

line section. The conductor’s time constant

matches well with sampling rates and the

cycle time for state estimator analysis that

uses the DLR data to minimize wide variations

in ratings due to transient parameters.

Once a line rating is determined, a

protocol is required to bring this information

to the operating environment so that the real-

time rating can be applied to operate the grid

area in which the line is located.

DLR Systems

The key parameter to determining the DLR is

the effective wind speed along the stringing

section.

For a Drake conductor (a common

transmission line conductor) using typical

summer climate assumptions, a decrease

in effective wind speed from 0.2 m/s to

0.1 m/s results in a rating reduction of 14 per

cent. Since the wind speeds of interest are

very low, in the range 0–2.0 m/s, there are no

meteorological services that monitor these

levels along the line.

Even a distributed network of anemometers

would require too extensive a deployment

of instrumentation by a utility to be viable.

The more practical solution is to obtain the

effective wind speed by deriving the value

from the conductor temperature.

Deploying the DLR system requires a

selection of monitoring locations in order

to develop the rating for each line section,

differentiated from the next by conductor

size, stringing and loading design criteria,

line orientation to prevailing winds and line

loading.

If the line has long tangent sections, it

may be necessary to put more than one

sensor device in the line section. The SGDP

project validated that a tension or conductor

position monitor can easily characterize the

performance of 8 km of line.

From a capacity standpoint, the data

shows that the DLR exceeds the SLR rating

99 per cent of the time, and exceeds it by

more than 110 per cent between 93 per cent

and 97 per cent of the time.

The results of the SGDP project illustrate

that real-time monitoring and application of

DLR is essential to optimal application of the

methodology. This is because the dynamic

ratings for each line vary in real time and over

the long term. It is not suffcient to collect data

for a certain length of time on a few lines to

characterize the dynamic rating potential of a

transmission line or a system of lines.

Applying the technology

The importance of DLR is to capture real-time

information and then calculate the maximum

current that can be carried by the entire line

while maintaining safe operating criteria –

setting a maximum operating temperature

that maintains the required ground clearance.

There is a signifcant level of unused spare

capacity that could help to address grid

congestion issues if it can be accessed.

Credit: Oncor

1411PEI_41 41 11/10/14 9:48 AM

42 www.PowerEngineeringInt.com

Transmission & distribution

Power Engineering International November 2014

Any DLR system should be evaluated with

respect to cybersecurity concerns relating to

data integrity and system security.

There are two strategic ways to apply the

DLR information: system operations query

system and autonomous streaming telemetry

to state estimator.

The difference between the two methods

is how system operations accesses the DLR in

order to apply them.

System operations query system: In this

application, the DLR data is made available

to System Operations on a control room

screen.

Oncor uses an ambient temperature-

adjusted rating based on the ambient

temperature from a weather station assigned

to each line.

This format calls for the operator to

recognize a need for additional ratings,

recognize that the line has DLR available and

then decide to allow the system to operate at

that level.

This places considerable dependence on

the operator to take additional operational

decisions.

The SGDP project demonstrated the

benefts of using DLR in an autonomous

protocol that streams the data automatically

to the system state estimator so that the

dynamic rating can be applied continuously

in real-time.

This technique provides several advantages

for grid operations. The transmission grid

is operating closer to its true functional

capability, is continuously monitored and

managed by the most recent and relevant

data, and relieves the system operator of

additional workload.

Within the protocol, the system has built-in

quality and integrity checks that are executed

before passing the data to the state estimator.

These validate that the ratings returned by

the DLR system are within an acceptable and

expected range. If the validity checks fail, the

system reverts to the line rating that is normally

applied.

One of the concerns that many operators

have in making the query-based decision

when applying DLR is that they are unsure of

what the rating may do in the near term.

If they are increasing the line capacity

based on DLR ratings, they may have concerns

about how long the rating will remain elevated

and how it could drop in the short term.

Furthermore, each different control room shift

has operators with different experience with

line performance and their decisions may be

different case to case, shift to shift.

Continuous monitoring

iDLR ratings have the advantage that the

operator is not burdened with making

additional decisions. The real-time nature

of iDLR also adds a component of Wide

Area System Awareness (WASA) to the line

operation by continuously monitoring the

line’s state.

The cycle time for monitoring the line

and reporting to the state estimator can

be adjusted and synchronized to the state

estimator’s cycle of managing the grid, so that

the system becomes self-resolving. If the wind

should die off, the conductor heats up and

iDLR levels reduce, the system automatically

adjusts the operation to maintain system and

line reliability.

The iDLR streaming protocol has proven to

be a more reliable and consistent application

of DLR than the operator query based system.

The continuous WASA aspects of iDLR provide

system reliability as well as increased capacity

when available. The reduced operator

work load, reduced personnel training

requirements and consistent availability make

the iDLR stream of ratings a valuable tool in the

operating environment.

Project results

The fnal report published on the Oncor SGDP

Project highlighted several conclusions and

breakthroughs.

Oncor found that using DLR increased

capacity by 14 per cent above the

ambient temperature-adjusted ratings. The

incremental capacity was available from

83.5 per cent to 90.5 per cent of the time.

In addition, the project found that

5 per cent additional capacity could relieve

congestion by up to 60 per cent on the

target lines with DLR installed, while 10 per

cent additional capacity would practically

eliminate all congestion on the target lines.

Congestion on the Oncor transmission lines

in 2011 and 2012 cost more than $148 million

and $197 million respectively. Increasing

capacity is useful on overhead lines where a

full upgrade cannot yet be justifed.

By providing additional capacity, DLR can

be utilized in the planning process to enable

a least-regrets capital strategy, minimizing any

potential stranded investment.

The integrated Dynamic Line Rating (iDLR)

system feeds real-time conductor ratings

to ERCOT, the market operator, who then

incorporates the additional capacity into

its Security Constrained Economic Dispatch

process. With zero operator intervention, DLR

capacity is used to increase market effciency.

As evidence of the extensibility of DLR

technology, in June 2013 Oncor deployed

additional DLR systems in the Odessa-Midland

region of Texas in a commercially funded

follow-on project.

For other transmission owners considering

using DLR, the project authors have developed

a guide.

While this project has focused on a US

application, the principles apply worldwide.

And we are already seeing signifcant interest

in Europe.

Sandy Aivaliotis is senior vice-president,

Operations, Technology and Business

Development at Nexans’ The Valley Group

Visit www.PowerEngineeringInt.com for more information i

Overhead conductors exhibit a certain level of ‘sag’ when strung between their supporting towers.Credit: Oncor

1411PEI_42 42 11/10/14 9:48 AM

For queries relating to the

conference, please contact:

POWER-GEN Russia:

Emily Pryor

Conference Manager

T: +44 1992 656 614

E: emilyp@pennwell.com

HydroVision Russia:

Mathilde Sueur

Senior Conference Manager

T: +44 1992 656 634

E: mathildes@pennwell.com

For information on exhibiting and

sponsorship, please contact:

POWER-GEN Russia:

Gilbert Weir Jnr

Sales Manager

T: +44 (0)1992 656 617

F: +44 (0)1992 656 700

E: gilbertw@pennwell.com

Svetlana Strukova

T: +7 495 249 49 15

F: +7 495 249 49 15

E: svetlanas@pennwell.com

HydroVision Russia:

Amanda Kevan

T: +44 (0) 1992 656 645

F: +44 (0) 1992 656 700

E: amandak@pennwell.com

POWER-GEN Russia (formerly Russia Power), co-located with HydroVision Russia, provides an ideal setting

to explore business opportunities, meet new partners, suppliers and the industry’s most infuential decision-

makers. The combined 2014 event combined attracted over 5,000 attendees from over 50 countries.

Featuring a busy exhibition foor with the pre-eminent organisations from the Russian and international

energy sector, POWER-GEN Russia and HydroVision Russia offers excellent networking opportunities.

WHY YOU SHOULD EXHIBIT IN 2015

$% &�%����%��%���%������%����%�����%�% ����

$% �������%��%��������%���%���%������%����������

$% �����%�����%�������%�������%���%��%��������

$% �������%��%������%������%������%���%��������%�%���%�����%����%������

$% ��������%��%�������%����%�������%����%�������%�����%�������%���%���% ����%����

$% ������%���%����%���%���!��%������������%���%�����%��������%�%���%�����%

$% "��%�����%���%���%�������%�����%��������%�����%���������%����%���%��%���������

$% #��%���%��%����%�����%���%���%������

�����������% ���%�������% �% �% �������%��������%����������%���������%���������%��%�����������%

from the industry, for the industry. For further information on exhibiting please contact your local

sales representative.

INVITATION TO PARTICIPATE

REGISTER NOW TO ATTEND RUSSIA’S PREMIER POWER EVENT

POWER-GEN Russia and HydroVision Russia is now open for Registration! Make sure

you register, attend, learn and network with high-level executives, professionals and

other leading decision-makers in the industry.

For information on registration pricing and how to register, please visit:

www.powergen-russia.com or www.hydrovision-russia.com.

Conference & Exhibition

3 - 5 March 2015

Expocentre, Moscow, Russian Federationwww.powergen-russia.com | www.hydrovision-russia.com

Owned and Produced by:

®

Presented by:

www.powergen-russia.com | www.hydrovision-russia.com

Æ

PROVIDING ENERGY SOLUTIONS & INNOVATION

For more information, enter 20 at pei.hotims.com

1411PEI_43 43 11/10/14 9:48 AM

As parent body organization

to the two site licence

companies (SLCs) Magnox

and RSRL, CFP has begun

the process of implementing

its approach to manage

the decommissioning of 12 nuclear sites,

and deliver each to an agreed and defned

point – either interim end state or into care

and maintenance – while providing savings

anticipated to be over £1.5 billion ($2.4 billion)

against the previous site lifetime plans.

It is no small undertaking, and in taking on

this mission Cavendish Fluor Partnership, a joint

venture between British company Cavendish

Nuclear and US frm Fluor, will be drawing on

its extensive UK and US decommissioning

experience.

Indeed, this experience has already been

applied, in the frst instance, to conduct a

successful fve-month transition programme –

a critical phase in advance of offcial contract

award and implementation of the new

programme – to ensure a seamless handover

from two PBOs to the new one, with minimal

impact on the existing teams and continuity

of work taking place at the 12 sites.

The transition phase was an intensive period

and a major project in itself. Cornerstones

of this phase, which concluded on

31 August, included introduction of the new

management team to the SLC management

and workforce, and stakeholder engagement

as well as completion of initial due diligence

on the site’s lifetime plans.

The transition period also saw

preparations for the necessary organizational

transformation, as well as ensuring that all

regulatory requirements were met and the

highest level of safety standards implemented.

As part of the due diligence requirement,

progress on all site plans was assessed by the

new team against the information gained

and assumptions made in the bidding

process, to identify the additional work that will

be required to be undertaken.

Equally importantly, the transition period

also provided the opportunity for the

Cavendish Fluor Partnership to gain a better

understanding of the processes being

worked to, the procurement activities, supplier

contract status and existing site initiatives,

while also getting to know the people and the

12 sites. This will feed into the changes required

to implement CFP’s lifetime plans which will

differ in a number of ways from the existing site

plans.

Strategic approach

Following successful completion of the

transition contract, implementation of the

strategy for the 12 sites is now underway.

Nuclear decommissioning

The UK’s Nuclear Decommissioning Authority has awarded Cavendish Fluor Partnership a contract for the decommissioning of 12 UK nuclear sites. Kenny Douglas looks at how this joint venture proposes to meet the challenge to decommission the sites safely and to schedule

A ‘programmized’ approach to nuclear decommissioning covers safety, organizational transformation and integrated management as well as technical innovation

Credit: Magnox Ltd

44 Power Engineering International November 2014 www.PowerEngineeringInt.com

A new approach

1411PEI_44 44 11/10/14 9:51 AM

www.PowerEngineeringInt.com 45Power Engineering International November 2014

Nuclear decommissioning

This approach is characterized by a

number of key features covering safety,

organizational transformation and integrated

management – a ‘programmized’ approach

– and technical innovation, ensuring that the

work required is undertaken safely and at

minimum possible cost.

Implementing an affordable schedule

to undertake the work and taking a

‘programmized approach’ are vital facets of

the strategy. The approach is based around

ten core programmes and the organizational

structure will progressively align to these

programmes across all the sites.

Technical innovation is a further key

element of the strategy, drawing and building

on experience and proven techniques and

technologies, both from within the nuclear

industry and the partners’ own experience in

the UK and US, while also potentially bringing

best practice or technologies from other

industries where this adds value.

Part of the approach will be to work with

the SLC teams to ensure that the appropriate

technical approach is undertaken for each

site. These differing approaches are being

developed between the CFP secondees

and the SLC teams in order to optimize the

solutions included within the bid.

One of the new programmes that

will be introduced, for example, is asset

management in order to standardize and

right-size the maintenance programme at

each of the sites at the differing stages of their

decommissioning programme.

A central tenet of the strategy is to gain

approval to have a single organization

running the two site licence companies, with

the option to re-licence into one site licence

company being explored with the appropriate

regulatory authorities.

CFP is seeking, from the early stages, to

standardize the processes and approach

taken across all 12 sites, and to maximize

learning across all locations.

For instance, approval for a programme

gained at one site will then be replicated

across the other sites, while incorporating

learning from experience at each – an

approach known as ‘lead and learn’ –

which effectively integrates the approach

and programmes across all the sites, while

delivering locally.

Another intended initiative and part of the

standardizing of processes across the sites is

the modularized safety and environmental

case approach, with a safety case interface

software tool.

This involves taking a generic approach

wherever possible, with an overarching

framework strategy, developing a safety

and environmental case at one site and

then checking for design differences and

adapting it to the next site in line with site-

specifc requirements, retaining procedures

as appropriate and sharing or transferring the

learning and experience gained.

Additionally, long-term employment

opportunities for the SLC workforce are a key

facet of the CFP approach. Notably, following

CFP’s appointment as PBO, Magnox and

RSRL employees are now part of the largest

nuclear Suitably Qualifed and Experienced

Personnel (SQEP) team in the UK. Cavendish

Nuclear and Fluor recognize that their people

are theirmost important asset, while both

PBO partners are ambitious and growing

companies with interest in the UK’s new-build

programmes (four of which are due to take

place adjacent to Magnox sites).

With this in mind, CFP will ultimately seek

to manage, at the appropriate time in the

future, the transition of the skilled workforce

from decommissioning into the new-build

programme, with opportunities for the

workforce members to work on new projects

within one of the two parent companies once

the decommissioning work is complete.

One further key aspect in the strategy to

deliver the requirement for the sites effciently

and successfully lies in the optimization of the

supply chain. This will be made up of various

facets, including taking a single approach,

category management, SME engagement

and SLC staff development.

Implementation and delivery

In short, the Cavendish Fluor Partnership

will manage the capability and experience

residing in the Magnox and RSRL

SLCs by agreeing the right strategy for

decommissioning and waste management,

turning that strategy into detailed programmes

with clear targets, choosing the right people to

deliver, adopting robust corporate governance

processes, providing incisive challenge and

demonstrating leadership. CFP will ensure

delivery of the plan, while constantly seeking

to reduce cost, learn from experience, and

seek to provide additional future employment

opportunities throughout the programme.

Key to delivering the established

goals and target cost reductions are

technical innovation, changing operating

arrangements, streamlining the organizational

structure and delivering the detailed

decommissioning and waste management

programmes. In implementing these, CFP will

ensure that the programme is delivered safely

and securely, without environmental impact,

on time and on budget, thereby fulflling its

primary role as PBO: to ensure safe delivery

of the decommissioning programme across

all the sites, with an integrated management

plan and system, ensuring that the NDA’s

vision is supported and requirements are met.

Kenny Douglas is managing director of

Magnox and RSRL

Visit www.PowerEngineeringInt.com for more information i

CFP will seek to manage the transition of the skilled workforce

from decommissioning into the newbuild programme

Credit: Magnox Ltd

1411PEI_45 45 11/10/14 9:51 AM

Global advances

in steam and gas

turbine technology are

persistently pushing the

envelope of metallurgy

and steam cycle design

effciency, resulting in more diverse operational

requirements for component manufacturers.

Greater gas turbine mass fows, and ever

increasing fnal superheated steam volumes

and temperature requirements, coupled with

multiple thermal cycles (per 24-hour plant

operational cycle) now place substantial

demands on critical and severe service

products.

Precise control of steam temperature is a

critical element for safe and effcient plant

operation. The sustained emergence and

demand for even larger and more super-

effcient combined-cycle power generation

facilities on the global market now drives the

need for a new generation of heat recovery

steam generator (HRSG) attemperator

systems. These desuperheaters must be able to

address the complex engineering challenges

and varied operational environment of today’s

modern 50- and 60-Hz combined-cycle power

generation markets.

Desuperheaters control steam temperature

by injecting water into the steam fow within

the boiler circuit. This direct contact between

the steam and water causes atomization and

evaporation, resulting in a decrease in steam

temperature. Due to the high temperature,

pressure and mass density of the steam, there

is substantial risk of component wear and

thermal shock damage, which increases the

risk of failure and impact on plant effciency.

Rapid varying load conditions are

typical of combined-cycle plants (CCPs)

and place strenuous duty cycles on steam

attemperation components and downstream

apparatus. Depending on the boiler

operating characteristics and the extent

of load changes it is subjected to, a steam

attemperator can experience extensive

thermal cycling. Temperature differentials

between the steam fow and spray water,

Heat recovery steam generators

The new generation of desuperheaters must be able to address the complex engineering challenges and varied operational environments of today’s modern 50- and 60-Hz combined-cycle power generation markets, writes Martin-Jan Strebe

Desuperheaters rise to new challenges

A laboratory image of droplet size analysis

Credit: Pentair Valves & Controls

46 Power Engineering International November 2014 www.PowerEngineeringInt.com

Martin-Jan Strebe

1411PEI_46 46 11/10/14 9:54 AM

www.PowerEngineeringInt.com 47Power Engineering International November 2014

Heat recovery steam generators

intermittent desuperheater operation and low-load boiler operation all

contribute to potential attemperator failures. This can lead to common

problems, including cracks in material welds and older spray nozzle

designs, cracks in the thermal lining (or in the attemperator steam line

within a liner that is not used) which can cause pieces to break off, and

broken spray nozzles which can become lodged in the venturi, causing

a steam fow blockage and pressure drop.

Understanding the necessary desuperheater performance

characteristics for effective steam temperature control requires

exploration of the balance between design effciency, component

fexibility and system reliability.

Atomization is key

Water droplet atomization requires a precise methodology to improve

understanding of primary and secondary atomization within the

pipeline prior to evaporation and steam cooling. This process is ultimately

predictable and measurable based on constant fuid dynamics. If

atomization of spraywater into the steam system is negatively affecting

the temperature probe’s ability to measure correct downstream steam

temperature, this could create severe overspray and underspray

conditions which result in increased thermal cycles and damage to

system components.

Primary atomization of the cooling water is caused by the nozzle

design and geometry within the desuperheater and the pressure

differential between the cooling water and the steam. Pentair Valves

& Controls has previously developed theoretical modelling of primary

atomization using computational fuid dynamics (CFD) analysis and

laboratory laser diffraction to analyze water droplet size upon discharge

from the desuperheater. This testing examined two steam attemperator

nozzle designs, spring-loaded and swirl nozzles. Results identifed that

when operating at 25 bar with a 0.05 mm lift and Kv 0.047, spring-loaded

nozzles produce droplet sizes of 87 µm. The same calculation for swirl

nozzles at 25 bar, Kv 0.043 resulted in droplet sizes of 27 µm – a factor of

two to four times smaller than spring-loaded nozzles, depending on the

operational pressure range.

Using this data, Pentair Valves & Controls analyzed the secondary

atomization characteristics which occur when the speed differential and

drag forces between the cooling water and pipeline media cause the

droplets to split into smaller sizes. This occurrence is calculated by:

By measuring the speed differential of the two nozzle designs, Pentair

defned which nozzle achieved higher speeds and therefore faster

secondary atomization. Optimum atomization will result in frictional

forces breaking the droplet size, which results in complete mixing and

true temperature control and measurement.

These results demonstrated that swirl nozzle designs offer enhanced

performance and maximum use of water pressure DeltaP for atomization

in the shortest possible length. Optimized spray injection angles of swirl

nozzles allow equal temperature distribution within the pipeline and

provide the highest turndown ratio due to mass fow, rather than pressure

control. No springs or moving parts within the nozzle and no pressure drop

and cavitation in the control valve maximizes the operational lifecycle of

the swirl nozzle design compared to spring-loaded nozzles. Combining

We = p.D.V²

σ

(If We >14, secondary atomization occurs)Improving access to your plant with rack and pinion

lifts from Alimak Hek increases labor efficiency,

reducing the labor required to complete planned

outages and routine maintenance. It also gets the

plant back online faster, so utilities can start gener-

ating additional power – and revenue – sooner.

Learn more about vertical access solutions

from Alimak Hek. Contact us today.

www.alimakhek.com

A PowerfulInvestment That Pays OffQuickly

For more information, enter 21 at pei.hotims.com

1411PEI_47 47 11/10/14 9:54 AM

48 www.PowerEngineeringInt.comPower Engineering International November 2014

Heat recovery steam generators

this analysis with Pentair Valves & Controls’

experience in steam attemperation provided

an insight into desuperheater performance

characteristics for engineering design criteria

to support new product development.

Effective nozzle design

Operating at today’s higher temperatures and

cycling ratios places high thermal stresses

on critical components, and effective steam

temperature control is needed to protect this

vital equipment. Many plant operators are

looking to maintain steam temperature control

and the most effective ways to achieve this

are through the design of the shortest possible

evaporation length. Critical to achieving this is

uniform and consistent atomization through

small droplet sizes. Robust nozzle design offers

plant operators an optimized solution that

delivers effective performance and maximum

component lifecycle to avoid unnecessary

plant shutdown, maintenance and product

replacement.

Optimum desuperheater performance

requires evaporation of the spraywater to take

place as quickly as possible in the shortest

length within the pipe to avoid water droplet

impingement. Low steam velocity and large

droplet sizes create water fallout inside the

pipe, creating cold spots and thermal stress

points which risk pipeline failure. In developing

the next generation of desuperheater

technology to meet the evolving needs of

plant operators, Pentair Valves & Controls,

through its Yarway brand, wanted to

identify which nozzle type offered the best

performance in relation to water droplet size

and spray pattern. Documentation to support

this product development was limited, with

little data to support an analysis of nozzle

performance.

To understand the design rules for

desuperheaters to achieve optimized

steam temperature control, Pentair Valves &

Controls embarked on a research project

with the University of Eindhoven in the

Netherlands. The goal of this cutting-edge

research was to undertake an assessment of

existing desuperheater nozzles, focusing on

spring-loaded and swirl nozzle designs. This

assessment would help to identify the design

correlations of spray characteristics, which

could then support a product development

roadmap for improved nozzle design.

In spray generation, a viscous liquid sheet

breaks up and becomes unstable due to

capillary, aerodynamic and liquid viscous

forces. Primary break-up of the cooling water

typically takes place in the wake of the spray

nozzle during the frst 10 mm, with complete

atmomization taking place at around

25 mm downstream of the nozzle. The pressure

differential between the spraywater and steam

is vital for both water atomization and the

rangeability between maximum and minimum

water fow. Along with spraywater temperature

and nozzle design, the maximum pressure

differential directly affects atomization at the

smallest droplet size. Spraywater pressure

is ideally 150–1000 psi (10–70 bar) greater

than the steam pressure to provide optimum

vaporization speed and maintain controllable

low fow levels. While many desuperheaters are

capable of operating at much lower levels,

there is a direct correlation between pressure

differentials and component performance.

To better understand the impact of

spraywater characteristics on steam

attemperator performance, Pentair Valves &

Controls studied the functional operation of

pressure swirl nozzle and spring-loaded nozzle

designs. Both nozzles produce a hollow cone

spray with a spray angle between 80° and

120°. The hollow cone inside a swirl nozzle is

created by enforcing a natural swirling action

where the spraywater is injected through

tangential or helical inlet ports into a swirl

chamber. This nozzle design creates strong

rotational and axial velocity components

and a thin conical sheet forms at the exit of

the nozzle due to the large centrifugal force.

In spring-loaded nozzles this hollow cone is

mechanically created. When the pressure

increases the valve opens with a certain lift

and the spraywater exists via a small circular

slit.

0

0.10 1.00 10.00 100.00 1000.00

0.00

2.50

5.00

7.50

10.00

50

100

0

2 10 100 1000 2000

0.00

2.50

5.00

7.50

10.00

50

100

Example of non-uniform and unsteady spray pattern and droplet size

distribution for a spring loaded nozzle

Droplet size distribution for pressure swirl nozzle type B; ΔP=20 bar;

solid line corresponds to left axis, histogram to right axis

1411PEI_48 48 11/10/14 9:54 AM

Invitation to ParticipatePOWER-GEN Africa, co-located with DistribuTECH Africa, will once again provide comprehensive

coverage of the power needs, resources, and issues facing the electricity generation industries

across sub-Saharan Africa.

The event will feature a multi-track conference covering strategic, technical and renewable topics

with practical solutions and benchmark case studies and concurrent exhibition foor featuring prime

movers showcasing the very latest equipment and technologies.

POWER-GEN Africa has quickly established itself as sub-Saharan Africa’s premier and leading

event dedicated to the power generation industry, focusing on the current and future trends, as well

as the needs and resources within this region of the world.

Nowhere else provides you with the opportunity to reach and meet over 3,000 high-level industry

professionals in one place, allowing networking, business and sales opportunities with key industry

buyers and infuencers from around the continent.

Owned and Produced by: Host Utility: Presented by: Supported by:

Leon Stone

Exhibition Sales

International

T: +44 (0) 1992 656 671

E: leons@pennwell.com

Andrew Evans

Exhibition Sales

Africa

T: +27 (0) 21 930 9515

E: andrewe@pennwell.com

For booth bookings and

sponsorship enquiries,

please contact:

Co-located with:

To register and obtain further information, visit www.powergenafrica.com

EMERGING OPPORTUNITIES IN THE

WORLD’S FASTEST GROWING CONTINENT

Conference & Exhibition

15–17 July 2015

Cape Town International Convention Centre, Cape Town, Republic of South Africa

www.powergenafrica.com

Supporting Association:

EARLY BIRD

DELEGATE DISCOUNT

SAVE AT LEAST $200 IF

YOU REGISTER BEFORE

17 JUNE 2015

For more information, enter 22 at pei.hotims.com

1411PEI_49 49 11/10/14 9:54 AM

www.PowerEngineeringInt.com50

Heat recovery steam generators

Power Engineering International November 2014

Pentair Valves & Controls and the

University of Eindhoven defned set research

parameters for both the pressure swirl nozzle

and spring-loaded nozzles. Experiments

used demineralized water in temperature

range 5°C–85°C and set pressure between

8–70 bar, with a maximum of 8x nozzles. The

characteristics measured during the tests were

spraywater pattern, drop size distribution and

spraywater velocity. A Malvern Spraytec laser

diffraction system with a 100 mm diameter

enabled measurement of spray particle and

droplet size distribution in real-time. Using a

Dantec Laser Doppler Anemometry (LDA)

optical technique, accurate measurement

of velocity and turbulence distribution could

be measured in order to gain a clearer

understanding of fuid mechanics of the

spraywater characteristics of both nozzle

types.

Applying research results

Many plant operators are looking to maintain

steam temperature control. The most effective

ways to achieve this are through the design of

the shortest possible evaporation length within

the attemperator system, together with equal

temperature distribution within the steam and

high turndown ratio. Combining the results

of the computational modelling and this

latest research from Pentair Valves & Controls,

further understanding can be gained to

achieve more effective desuperheater

performance, particularly in combined-cycle

and heat recovery steam generator (HRSG)

applications. Using this data enables the

effective application of theoretical models to

identify the nozzle design and engineering

considerations for successful primary and

secondary atomization, evaporation and

defned spraywater characteristics. By

examining the results of Pentair Valves &

Controls’ research, it is possible to identify the

design correlations of these parameters and

understand how each nozzle type impacts on

desuperheater performance.

Spring-loaded nozzle

The research results defned the spraywater

characteristics as not uniform and not steady,

which causes potential water fallout. Uneven

and inconsistent distribution of droplet size

affects atomization within the pipe and

results in longer and slower evaporation,

affecting precise steam temperature control.

These characteristics are typically created

by restrictions in the nozzle design caused by

tolerances engineered into the nozzle, which

creates gaps and impact on the spraywater

pattern.

Pressure swirl nozzle

Under performance testing as part of Pentair

Valves & Controls’ research, this nozzle design

delivered a uniform and steady spray pattern.

In comparison to the spring-loaded nozzle

design, this nozzle delivers much smaller

droplets to achieve evaporation more quickly

and in a shorter pipe length. The uniform,

hollow cone spray pattern ensures even

droplet size distribution within the pipe and

minimizes impingement and water fallout.

These characteristics demonstrate faster

response times and more accurate steam

temperature control to help plant operators

improve the precision and operational

effciency of the boiler circuit.

Higher performance solution

The research results conclude that spring-

loaded nozzles deliver a spray pattern and

water droplet distribution that is both non-

uniform and unsteady. This indicates that this

nozzle design is best suited to less critical

process conditions or unit operations. The

robust pressure swirl nozzle provides a higher

performance solution for critical and severe

applications, such as steam attemperation.

The future design of higher effciency and

high cycling duty CCPs will lead to higher

steam temperatures and fows. Addressing

the requirement for more effcient power

generation will drive forward material

development and innovation and combine

these properties with the need for continued

operation, scheduled maintenance and

repair. Improving the design and engineered

performance of critical components is key

to meeting the power generation industry’s

future requirements and ensuring maximum

plant uptime. Investment into sound research

using modern methodologies and techniques

is one solution to delivering new, advanced

technology to plant engineers and operators.

In collaboration with the University of

Eindhoven, Pentair Valves & Controls has

identifed new correlations which have been

generated for the discharge coeffcients,

sheet velocities and drop size distribution

parameters of various types of pressure swirl

nozzles. As the operational and functional

design requirements of steam attemperator

systems continue to evolve, this engineering

research and design understanding will be

critical in the development of new technology

to meet these new challenges. Component

performance data, advanced detailed 3D

computer modelling, and material and

industry design experience are providing the

tools for this next generation of attemperator

systems. The work that manufacturers such

as Pentair Valves & Controls undertake is an

integral step in this process, using qualifed

research and testing to improve product

design and push the industry towards higher

effciency, reliability and safety.

Martin-Jan Strebe is Global Product Manager,

Control Valves at Pentair Valves & Controls

Visit www.PowerEngineeringInt.com for more information i

Testing examined two steam attemperator nozzle designs: spring-loaded and swirl

Credit: Pentair Valves & Controls

1411PEI_50 50 11/10/14 9:54 AM

PennWell Global Energy Group, The Water Tower, Gunpowder Mill, Powdermill Lane, Waltham Abbey, Essex EN9 1BN, United Kingdom.Phone: +44 1992 656 600 Fax: +44 1992 656 700 Web: www.PowerEngineeringInt.com

Publisher Heather Johnstone peinews@pennwell.com Chief Editor Kelvin Ross peinews@pennwell.com Associate Editor Nigel Blackaby peinews@pennwell.comProduction Editor Richard Gibson Studio Manager Karl Weber Design Samantha Heasmer Production Daniel Greene Group Publisher Glenn EnsorAdvertisement Sales Manager Anthony Orfeo anthonyo@pennwell.com Advertisement Sales Manager Asif Yusuf asify@pennwell.com

Corporate Headquarters PennWell Corporation, 1421 S. Sheridan Road, Tulsa , OK 74112 USA. Phone: +1 918 835 3161 Fax: +1 918 831 9834 Sr. VP Audience Development and Book Publishing June Griffn Audience Development Manager Linda Thomas Chairman Frank T. Lauinger President/CEO Robert F. BiolchiniSubscriber Customer Service: PO Box 3264, Northbrook, IL 60065-3264, USA. Customer Service Phone: 1-847-763-9540. Fax: 847-763-9607. E-mail: pei@halldata.com

Power Engineering International, ISSN 1069-4994, is published eleven times a year by PennWell Global Energy Group, ©Copyright 2014 by PennWell Corporation, 1421 S. Sheridan Rd., Tulsa, OK 74112, USA. All rights reserved. Subscriptions/circulation and reader enquiry offce: Power Engineering International, PO BOX 3264, Northbrook, IL. 60065-3264, U.S.A. Paid annual subscription rates: Worldwide $60 Digital Version. E.U. $173, No. America $214. United Kingdom $143. All other countries $214. Single or back copies: $26 for all regions.

Reprints: If you would like to have a recent article reprinted for a conference or for use as marketing tool, please contact Rae Lynn Cooper. Email: raec@pennwell.com.

USA circulation only: Power Engineering International, “Periodicals POSTAGE PAID at Rahway NJ”. Subscription price is $210 Periodicals Postage Paid at Rahway NJ. Postmaster send address corrections to: Power Engineering International, C/O Mercury Airfreight International Ltd. 365 Blair Road, Avenel, NJ 07001. ® “Power Engineering International” is a registered trademark of PennWell Corporation. POSTMASTER: Send address changes to Power Engineering International, PO BOX 3264, Northbrook, IL. 60065-3264. U.S.A. Member American Business Press • Business Publications Audit3 • Printed in the United Kingdom • GST No. 12681315

ALIMAK HEK AB 47

AMETEK PROCESS ANALYTICAL 11

ASEAN POWER WEEK 39

AUMA RIESTER GMBH 29

AVEVA SOLUTIONS LTD 13

CUMMINS POWER GENERATION C2

DNV ENERGY 7

ELETROBRAS 21

GP STRATEGIES C4

HEMPEL A/S 17

HILLIARD CORPORATION 33

HYDROVISION 2015 37

HYTORC INDUSTRIAL TOOLS 23

MARELLI MOTORI SPA 15

PETRO CANADA 2-3

POWER GENERATION WEEK 2014 C3

POWER-GEN 200 35

POWER-GEN AFRICA 2015 49

POWER-GEN RUSSIA 2015 43

RS ROMAN SELIGER 9

SIEMENS AG 25

SIPOS AKTORIK GMBH 19

STRUCTURAL INTEGRITY ASSOCIATES 31

VAISALA OYJ 51

WELLAND & TUXHORN AG 27

WESTINGHOUSE ELECTRIC CO 5

Ad Index

www.PowerEngineeringInt.com 51Power Engineering International November 2014

Listen to our free webinar “Moisture Dynamics in Power Transformers” at any suitable time for you at www.vaisala.com/powerLearn how moisture moves within a transformer and why online measurement is so important to yourtransformer maintenance planning and daily grid operations

Outages Happen 24/7. So Should Monitoring.

• See moisture fl uctuations in varying temperature and load conditions

• Receive early warnings of sudden changes in moisture, pressure

and density

• Avoid sampling and waiting for lab results – Act on real time trend data

• Integrate into condition monitoring and data acquisition systems

Real risks, real savings and real performance require

– quite simply – real-time monitoring. Let’s talk more.

Vaisala Online Measurements for Transformers and Switchgear

Dew Point / Moisture-in-oil / SF6 Density / Pressure

ons

data

For more information, enter 23 at pei.hotims.com

1411PEI_51 51 11/10/14 9:54 AM

www.PowerEngineeringInt.comPower Engineering International November 201452

DiaryDecember

Nuclear: Powering the UK4 December

London, UK

www.niauk.org/nuclear-powering-the-uk

Energy, Environment and Sustainable Economy Summit5–6 December

Bangkok, Thailand

http://iceese.org/

POWER-GEN International9–11 December

Orlando, Florida, US

www.renewableenergyworld-events.com

Nuclear Power International9–11 December

Orlando, Florida, US

www.nuclearpowerinternational.com

Renewable Energy World Conference & Expo North America9–11 December

Orlando, Florida, US

www.renewableenergyworld-events.com/

Visit www.PowerEngineeringInt.com

for more information i

2015

World Future Energy Summit19–22 January 2015

Abu Dhabi, UAE

www.worldfutureenergysummit.com

Nuclear Power Asia27–28 January 2015

Kuala Lumpur, Malaysia

www.nuclearpowerasia.com

Smart Energy UK & Europe Summit29–30 January 2015

London, UK

www.smuksummit.com

DistribuTECH3–5 February 2015

San Diego, CA, US

www.distributech.com

Nuclear Energy in the UK3 March 2015

London, UK

www.westminsterforumprojects.co.uk/

forums/event.php?eid=935

Hydrovision Russia3–5 March 2015

Moscow, Russian Federation

www.hydrovision-russia.com

Power & Electricity World Africa24–25 March 2015

Johannesburg, South Africa

www.terrapinn.com/exhibition/power-

electricity-world-africa/index.stm

Power & Electricity World Asia5–8 May 2015

Singapore

www.terrapinn.com/exhibition/power-

electricity-world-asia

POWER-GEN India & Central Asia7–9 May 2015

New Delhi, India

www.indiapowerevents.com

DistribuTECH India7–9 May 2015

New Delhi, India

www.indiapowerevents.com

The Asian Conference on Sustainability, Energy & the Environment13–16 June 2015

Osaka, Japan

http://iafor.org/iafor/conferences/

acsee2015/

POWER-GEN Europe9–11 June 2015

Amsterdam, The Netherlands

www.powergeneurope.com

Renewable Energy World Europe 9–11 June 2015

Amsterdam, The Netherlands

www.renewableenergyworld-europe.com

Hydrovision International14–17 July 2015

Portland, Oregon, US

www.hydroevent.com

POWER-GEN Africa15–17 July 2015

Cape Town, Republic of South Africa

www.powergenafrica.com

POWER-GEN Asia1–3 September 2015

Bangkok, Thailand

www.powergenasia.com

VGB Congress Power Plants 20159–10 September

Vienna Austria

www.vgb.org/en/pp_2015.html

Africa Electricity30 September–2 October 2015

Johannesburg, South Africa

www.africaelectricity.com

1411PEI_52 52 11/10/14 9:54 AM

Covering every aspect of the power generation industry, POWER-GEN International, NUCLEAR POWER International, Renewable Energy World Conference & Expo North America, POWER-GEN International Financial Forum and the GenForum converge in 2014 to form Power Generation Week. Beneft from fve days packed with pre-conference workshops, technical tours, over 70 conference sessions, panel discussions, three exhibition days and multiple networking events. Gain access to nearly every facet of the market – all under one roof.

Learn more at www.powergenerationweek.com

Owned & Produced by Presented by Supported by

>> DECEMBER 7-11, 2014 >> ORANGE COUNTY CONVENTION CENTER, WEST HALLS >>>> ORLANDO, FL, USA >> WWW.POWERGENERATIONWEEK.COM >>

For more information, enter 24 at pei.hotims.com

1411PEI_C3 3 11/10/14 9:54 AM

For more information, enter 25 at pei.hotims.com

1411PEI_C4 4 11/10/14 9:54 AM