Efficient Uses of Steam Energy

7/27/2019 Efficient Uses of Steam Energy

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Efficient Uses of Steam Energy in Textiles

to Reduce Cost & Improve Productivity

2nd International Conference on Textile & Apparel, ICTA-2012


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What We Do?

oForbes Marshall is an ISO 9001 company specializing in

the Field ofSteam Engineering & Control Instrumentation

o We are working with steam for last 106 years and haveour manufacturing facility in India and others in joint

venture with Spirax Sarco, ARCA, Krohne, Codel & Vynce.

o We manufacture Steam Boiler (NG/Diesel/Solid fuelfired), Exhaust Gas Boiler and almost all the steam system

accessories.


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Energy Audit

oForbes Marshall has an Energy Audit division having expertise in

specific fields.

oForbes Marshall has conducted over 100 detailed energy audits across

the industry covering each and every process including dyeing units,

washing units, denim plants etc.

o In each of our audits we identified the opportunity for savings ranging

from 20% to 30%.

o Successful implementation of our audit recommendations of these

plants has yielded significant improvements in Specific Fuel

Consumption (SFC).


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Why Steam?

o Fuel used for generating steam accounts for about 50% of total utility cost.

o Scarcity of Natural Gas, increase in cost of fuel and hence the steam costs

oEffective steam management plays a role in

Fuel Saving s- which can be leveraged for cost competitiveness . Reducing

fuel cost is the only route to cut costs substantially.

Produ ct Qual i ty

Maintaining proper steam parameters ensures product

quality, e.g. uniform colour, print, brightness etc.

Product iv i ty-Improving batch timings on equipment.


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Benchmarking where do we stand ?

Forbes Marshall studies of over 60

textile plants reveal differences in fuel

consumption within the industry.

39% difference in Specific Fuel

Consumption (SFC) between the best

and average plants.

The worst plant consumes more

than 3 times the amount of fuel as

compared to the best plant.


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Why is the best plant the best ?

Differences in Specific Fuel Consumption (SFC) across

plants on account of:

Efficient steam generation

Optimized steam distribution & utilization

Recovering condensate & flash steam

Proper steam trapping


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Comparative Study

Capacity

(Kg)

Ideal Steam Consumption with

Right Steam and condensate loop

(Without Heat Recovery/With

Heat Recovery* (Kg/Batch)

Actual Steam

consumption

(Kg/Batch)

Required

Steam

Pressure

(Barg)

Actual

Steam

Pressure

(Barg)

Batch

time

(mins)

Max

Gradient

(C/min)

Light Medium Dark Light Medium Dark

250 461/281 559/379 641/461 527 660 769 3.5 6-7 400-450 5

400 660/460 711/511 770/570 782 839 890 3.5 6-7 450-500 5

600 863/563 1227/927 1698/1398 907 1326 1950 3.5 6-7 500-550 5

750 1358/758 1817/1217 1922/1322 1585 1980 2160 3.5 6-7 550-650 5

1500 2227/1377 2490/1640 2769/1919 2531 2982 3187 3.5 6-7 650-700 5


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Common issues found because of not adopting right steam engineering

practices- Not getting right pressure & temperature in the m/c Batch time goes high and product quality hampered

Proper steam trapping is not in practice

Running boiler at lower pressure

Not using PRV before Process machine Not using temperature control

Many of the time traps are bypassed

Steam distribution system is not proper

Steam mains are oversized or undersized

Traps and valves leakage Insulation of Steam & Condensate line is not proper

Not recovering condensate & flash steam

Feed water temperature is ambient

Boiler blowdown is manual


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A 1/8 inch hole in

steam main can waste

15 tons of coal or 9

tons of fuel oil per

year.

Valve

Leakage


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A leaking 25 NB Thermodynamic Trap on a 7 bar line will

lose steam at the rate of 18 kg/hr. This translates to a loss

of more than 150 Tons of steam annually.


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Steam is venting

to the

atmosphere


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No Steam Trap / Group Trapping in Vertical Cylinder Dryer


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General Practice in Vertical Dryers

Group trapping

4 bar(g)

Overheated

+excessdriedcloth


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Recommended Hookup Vertical Dryers


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Existing Hookup Soft Flow


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Recommended Hookup


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Typical Steam Circuit:

Pan Pan

Boiler

Feed

Pump

Feed

Tank

Make-up Water

Vat

Condensate

Condensate

Steam

Steam

Steam Process

Vessel

Space

Heating

System


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The Steam and Condensate Loop

Boiler100% Input Process

Distribution losses 5-7%

85%

Boiler losses 13 - 15% 20% Condensate

60% Process

use

So, for 1 Ton steam for process, fuel used equal to 1.67 Ton


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Steam use in process 60%

Different losses 40%


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Steam Generation

Two things are directly effect boiler steam generation

- Boiler operating pressure & Feed water temperature

Poor boiler efficiency due to-

Fluctuat ing loads improper loading on the boiler which can be addressed by

proper boiler selection, capacity, burner turndown, etc.

Abs ence of diagnost ics to take correct ive act ion same can be addressed by

steam and oil flow metering, stack monitoring with boiler load management and online

efficiency check. Manual Blow down -because of over blow down losses of money and less blow

down increases the risk of boiler life.


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Cost of a Boiler

Oil/Gas fired


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Steam to Fuel Ratio

Radiation

FuelFlow

Burner

LossesStack

EnthalpyUn Burnt

Boiler

Draft

Blow down

SteamFlow

Air

BOILER HOUSE


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What affects Fuel Bill?

Excess Air %

Feed Water Temperature

Stack temperature

Un burnt losses

Number of On-Offs

Scaling on tubes

Soot Deposition Blow down TDS

Moisture in Fuel


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What to Monitor inside Boiler House ?

1. Steam Flow

2. Steam Pressure

3. Fuel Flow

4. S: F ratio

5. Stack Temp

6. % O2 in Flue gas

7. Feed Water Temp

8. Blow down TDS

9. Furnace Pressure


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Deviation in 2% oxygen Results in 1.5

% Excess Fuel Consumption 10 % Excess Blowdown will amount to

2 % Excess Fuel Consumption

Factuals


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Boiler Efficiency

Monitoring System


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Radiation

FuelFlow

Burner Boiler

Draft

Blow down

SteamFlow

Air

In DirectEfficiency

=

100 - { + }+

+

LossesStack

EnthalpyUn Burnt

Boiler Efficiency


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Fuel Scope forsavings (%)

Gas 11.2 %

Liquid 11.8 %

Solid 17.1 %

No Matter which fuel type you look at, thescope of savings is 10 % to 15 % at least.

No boiler is an exception

Conclusion


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Steam Distribution

High distribution loss across plants on account of -

oImproper line sizing

o Improper insulation

o Improper line routing & condensate removal from steam lines

These losses can be addressed by -

oProper design of the distribution network, i.e.; proper line sizing without extra

provisions for expansions

o Proper insulation and efficiency checking mechanism

o Proper condensate removal from steam lines

o Diagnostics pressure and temperature gauges, steam flow meters, etc.


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Distribute Steam at High Pressure

This will have the following advantages:

Smaller bore steam pipes needed and therefore less heat

(energy) loss due to the smaller surface area.

Lower capital cost of steam mains, both materials such aspipes, flanges and support work and labour.

Lower capital cost of insulation (lagging).

The boiler can be operated at the higher pressure

corresponding to its optimum operating condition, therebyoperating more efficiently.

The thermal storage capacity of the boiler is increased,

helping it to cope more efficiently with fluctuating loads,

and a reduced risk of priming and carryover


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Pipe Sizing

Greater Cost Greater Heat Loss

Greater Volume of CondensateFormed

Lower Pressure to Steam Users

Not Enough Volume of Steam Water Hammer and Erosion


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Waterhammer

Sagging Main

Slug of water fromcondensateVibration and

noise caused by

waterhammer

Condensate


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Relaying to Higher Level

Steam

Relayto high

level

Drain Points

30 - 50m

Fall 1/250

Steam Flow Flow

Proper Condensate Drain


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Proper Condensate Drain

Condensate

PocketSteam Trap Set25/30m

Cross

Section

Cross Section

Steam Trap Set

Steam Flow

Steam Flow

Correct

Incorrect


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Branch Connections

CorrectIncorrect

Steam Steam

Condensate


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Drainage of Condensate from Steam Line

Steam Flow

Separator


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Fig. Temperature profile across a heat

exchange surface

Importance of Moisture Separator


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Steam Utilization

Steam Trapping -

oIn most plants, trap selection is an issue on heatingapplications.

o Group trapping on equipment also needs to be addressed.

o Across textile plant audits and surveys we have conducted we

find that only 50% of the installed traps are OK.


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TD Traps are used in Process, it should be float trap

Disadvantages of TD:

-Intermittent discharge.

-Condensates not

removed properly, get

water logged.

-Increase steam

consumption by 8~10%

-Increase process time

By 25~30%


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Ball Float Trap:

Ensures proper removal of condensate from the process as soon as itforms. Recommended for process application.


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Condensate & Flash Steam Recovery

oHuge gap between quantum of condensate being recovered

and potential for recovery observed across all plants.

o Across many plants, boiler feed water temperature is ambient

and condensate is being drained.

o In plants where condensate is recovered, it is doing using an

electrical pump leading to loss of useful heat.

o Flash steam is normally not recovered and is vented. Flash

steam can be recovered and used for feed water heating.


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*This calculation is made for diesel fired boiler.

Similarly it can be done for gas fired boiler.


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o

Condensate water contains 20% energy of steam. Returning condensateimproves the feed water temperature and thus lowers fuel bill.

oReturning condensate to feed water tank cuts the makeup water

requirements.

o The condensate returned does not need to undergo water treatment and

thus saving treatment cost.

oIt has no TDS. It reduces the requirement of blowdown thereby

curtailing blowdown losses.

o Reduce the cost for oxygen scavenging chemicals, since the improved

temperature will reduce the amount of dissolve oxygen almost 75%.


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o Higher feed water temperature by recovering condensate

increases the boiler output with reduced fuel consumption.

oRecovering flash steam is as important as recovering

condensate water. Flash steam contains 50% energy of the total

recovered condensate, although it may be 10~15% in mass.

[Please Note: Holding condensate in co l lect ion tanks reduc es thecon densate temperature via radiat ion los ses. Condensate sho uld be

returned as soon as it formed. ]


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Benefits of Condensate Recovery:


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Energy Content in Dye Liquor

Not considering losses the Process Heat Recovery in Dyeing m/c

45 %

15 %

Dye Bath LiquorCooling Water

Energy Content


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Dye Liquor Heat Recovery

System

E t iti


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Trap Management

Selection of right Trap

Bypass

Leakage

Stop Leakages Insulation

Condensate Recovery

Flash Steam Recovery

Stop Blowdown Losses

Feedwater tank Management

Stop Waste (12-15%)

Enconomy opportunities

E t iti


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Optimization ( 8-10%)

Waste Management

Steam Flowmetering

Dye Liquore Heat Recovery

Efficiency Optimisation

Liquor ratio control

Steam Pressure Control

Temperature Control

Instant Hot water supply

Dryness of Steam

Capacity Utilisation

Encon opportunities

E O t iti


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Encon Opportunities

Boiler EfficiencyMonitoring

Waste Heat Recovery

Boiler from Generator

Thermic Fluid Generator-

Efficiency % optimisation

Hot water from DG set

JacketOptimization

Waste Management

Heat

Recovery

(7-8%)


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Our recommendations which included

o Optimized steam generation

o Improved steam distribution system

o Proper selection and sizing of steam traps

o Better management of the process like installing

temprature & pressure controls

o Utilizing waste heat recovery

o Recovering condensate with flash steam to improve the

boiler performance


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Copyright Forbes Marshall, 2006-07

Forbes Marshall has a Consultancy Division worked for the

project design and consultancy for steam, water & air

distribution system to make the industry energy efficient

and sustainable.

Forbes Marshall has done Consultancy in many industries of

Bangladesh. Few of them are,

Hameem Denim, DBL, Ecotex, GMS composite, Graphics

Textils, etc.

One of Many Successes in Bangladesh!!


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Copyright Forbes Marshall, 2006-07

One of Many Successes in Bangladesh!!

CuttingDown

CostsIndustry Knit ConcernLocation NarayangongSteam Usage Fabric Dyeing, Finishing & GarmentsFuel Gas

Before Energy Audit -

-They have a requirement of 3~4 TPH boiler

- Their machine was starving for steam

After Energy Audit & Implementing Recommendations

Till now they have no shortage of steam and no requirement of steam boiler

Reason found : Wastage and leakage of steam in different points

Condensate was not recovered

Boiler was running under pressure

Too much blowdown losses

Live steam wastages from garments section.
http://images.google.co.in/imgres?imgurl=http://www.dow.com/versene/images/textiles.jpg&imgrefurl=http://www.dow.com/versene/app/text/&h=272&w=250&sz=19&hl=en&start=1&tbnid=o6X_EFO_n3eTfM:&tbnh=113&tbnw=104&prev=/images%3Fq%3DTextiles%26svnum%3D10%26hl%3Den%26lr%3D


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One of Many Successes!


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CuttingDownCosts

Industry Textile Processing Unit

Location Gujarat

Steam Usage Yarn Dyeing M/cs

Fuel HSD

The objective Reduce Fuel Consumption

Energy conservation recommendations implemented by customer

-Optimized steam generation

-Reduced losses in steam distribution circuit

-undertook better management of process like temp control.

-optimized waste heat recovery dye liquor, condensate & flash recovery.

-reduced losses on account of inappropriate / in-operational trapping

The Results?

Customer Saves Rs 30 Lakhs/year!!

Before After Audit

Fuel Consumption (lts/day) 1,150 820

Costs (Rs/day) 17,250 9,020



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Cutting

DownCosts



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Cutting

DownCosts


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Find out where you stand!!!

Get a free scoping study done by FM Experts

Fuel prices would

continue to spiral

upwards. & so

would your losses!

The longer you wait..

The more your losses

accumulate!


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Bangladesh Office Address:

3rd Floor, Rupsha Tower, Kamal Ataturk Avenue,

Road -17, Banani C/A, Dhaka.

Email: [email protected]

Website: www.forbesmarshall.com


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