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Power Plant Performance Monitoring

Indonesia Customer Seminar

June 13 & 14 2012

Jakarta Indonesia

Why monitor Condenser Performance?

It is where the money is made or lost

Optimize cooling water program

Identify mechanical issues such as with air-removal systems

What is a Condenser and how does it work?

Nothing more than a heat exchanger

Condenses steam by transferring heat to cooling medium

The better the heat transfer rate, the better the vacuum, the more efficient the Steam Turbine/Plant

What is Nalco’s Condenser Performance Offering?

Condenser Performance Monitoring Tool (CPMT)

Captures plant data, as well as Trasar data

Compiles information, performs calculations, generates Dashboard for reviewing with customer

So how does the Condenser Performance Monitoring

Tool work?

Gathers the plant’s raw data for the key parameters

Uses these to make necessary calculations

Calculations provide quantitative information to trend condenser performance

So how does the Condenser Performance

Monitoring Tool work?

Graphs provide big picture view of condenser performance and allow for comparison of the key parameters

Most important is that it allows for filtering of data to compare like-for-like conditions

In the end the tool provides an accurate method of troubleshooting and identifying areas of improvement

What is required by the plant?

Provide the proper design documentation

Inform the Nalco Representative of any changes that have been or will be made to the Cooing or Condenser Systems

Help with set up of the Historian Download sheet

What is required by the rep?

Modification of the tool to fit plant’s needs

Periodic download of data from customer computer

Migration of that data to the tool

Analysis of that data with customer

DESIGN DATA ENTRY

What design data is needed?

Condenser

Design thermal and flow balance

Typically found in the Condenser Spec Sheet

Cooling

Cooling Tower spec sheet if applicable

For Once-Through’s, a thorough understanding of the pump operation is needed, particularly number of pumps for each season

Thermal Kit

Extremely valuable in comparing actual to design under all conditions

Contains information regarding Back Pressure vs Inlet Water Temperatures, as well as flow and heat load on the condenser

Design Data Entry

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Condenser Spec

Sheet

Cooling Tower

Spec Sheet

Design Data Entry

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Design Data Entry

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HISTORIAN DOWNLOAD

Data Capture

What operational data points are needed?

Basic points

Plant load

Steam Load

Condenser Back Pressure

Cooling Water In and Out Temps

Heat Rate- both net and gross

Cogen Steam if applicable

Ambient Temperature

Hotwell Temperature

What operational data points are needed?

“Would like to have” points

Cooling Water In and Out Pressures

Extraction Steam- or at least a % expected

Wet Bulb- if cooling tower

Humidity %- if cooling tower and no Wet Bulb

Each GT MW output- if HRSG

Fuel usage for all applicable systems

Important to note that we can pull anything into the tool

This allows us to trend other plant operations with the Condenser and Cooling Tower Performance

An example would be the 3D Trasar or NCSM data, which is captured by the unit, but not typically brought back to historian

Historian Download Setup

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Historian Data Download

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UPLOADING HISTORIAN DATA

Data Import

Accessing the CPMT and Importing Data

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GRAPHING TOOLS AND

DASHBOARD

Data Review

Graphing Options

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Dashboard

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WE HAVE THE DATA NOW

WHAT?

A Discussion about Condenser Performance

What parameters do we care about and why?

Steam

CW In Condensate

CW Out

Air

What are some key indicators of Condenser

Performance?

Back Pressure (BP)

Heat Rate (HR)

Air-In-leakage

Cleanliness Factor (CF%)

Initial Temperature Difference (ITD)

Terminal Temperature Difference (TTD)

Temperature Rise (TR)

Log Mean Temperature Differential (LMTD)

Performance Definitions and Calculations

ITD – temperature difference between the Steam Temp and the Inlet Water Temp

Stm – CWin

Can be key in identifying inlet water/cooling tower issues

TTD – temperature difference between the Steam Temp and the Outlet Water Temp

Stm – CWout

Indication of overall heat transfer and performance

Performance Definitions and Calculations

TR – temperature difference between CWout and CWin

Indication of how much heat was picked up by cooling water

Can be a good indication of fouling

LMTD - logarithmic average temperature difference

TR / ln(ITD/TTD) (for counter current)

In essence is the average temperature change across the tube bundle

Performance Definitions and Calculations

Distance Down Tube

Tem

pera

ture

TTD

ITD TR

Steam Temperature Constant

LMTD

Performance Definitions and Calculations

CF% = Ua / Ud

Ua = Q / A * LMTD

Ud = Ui * FL * F1 * F2

FL = Steam Load Factor

F1 = Inlet Water Correction Factor

F2 = Tube Gauge Correction Factor

Ui = Ideal Heat Transfer Coefficient

Industry standard but very much

misunderstood

What are some key aspects of Condenser Operation?

Performance Consequences- Turbine Efficiency

Efficiency of Turbine determined by BTUin and BTUout

Lower BTUout value = more btu’s transferred to Turbine

Therefore, lower BP in condenser, more BTU’s transferred to Turbine

3.0 inHg = 1111 btu/lb

101.5 psia = 1304 btu/lb

2.0 inHg = 1105 btu/lb

101.5 psia = 1304 btu/lb

Additional 6 btu/lb to Turbine and MW generation at lower BP

Performance Consequences – Inlet Water Temp

Many don’t consider this when discussing current operating BP

Inlet Water Temp dictates condenser performance

Assuming constant TR, every 2°F can mean as much as a 0.2 inHg increase in BP

Effect of Cooling Water Inlet Temperature

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1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

50 60 70 80 90 100 110

Back P

ressu

re i

nH

g

Cooling Water Inlet Temp f

Cooling Water In Temp vs. BP*

*Assumes 20°F TR and 6°F TTD

Performance Consequences – Air In-Leakage

Air In-leakage a significant contributor to degradation in condenser performance

Typically not monitored on-line

Typically not well understood

Blankets tubes preventing heat transfer Air Resistance

= Rair

Condensate

Resistance = Rcond

Tube Resistance

= Rtube

Scale/Foulant

Resistance = Rfoul

Water Resistance =

Rwater

U = 1/(Σ Resistances)

PITFALLS OF CONDENSER MONITORING

Important Considerations

Common Obstacles

Cycling plants difficult to monitor, but with a properly set up Thermal Kit and filtering, can be accomplished

The data is only as good as the tools used to collect it

Bad probes

Bad location

Not sent back to the historian

All play a role in poor data collection

Seeing what you want to see

Analyze the data, not what you would like to happen

Check multiple parameters to make sure they correlate

Make sure you understand plant operation/dispatch

Analyzing Data

Be patient

Look at all parameters before starting to form a conclusion

Because it is important to compare like conditions, start by filtering the data to the condition desired

Remember, you can filter on many parameters at once

For instance, you can filter plant load, inlet water temp, and date all at the same time to really drill down to what you are looking for

CASE STUDIES

Case #1- Vacuum Pump Seal Water

Case #2- Bio-Surfactant Addition

Mechanical

Cleaning

Surfactant

Addition

Case #3- Air In-leakage

DISCUSSION