Efficient Uses of Steam Energy in Textiles to Reduce Cost & Improve Productivity

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

What We Do?

o Forbes Marshall is an ISO 9001 company specializing in the Field of Steam Engineering & Control Instrumentation

o We are working with steam for last 106 years and have our manufacturing facility in India and others in joint venture with Spirax Sarco, ARCA, Krohne, Codel & Vynce.

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

Energy Audit

o Forbes 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).

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 Savings - which can be leveraged for cost competitiveness . Reducing

fuel cost is the only route to cut costs substantially.

Product Quality – Maintaining proper steam parameters ensures product

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

Productivity -Improving batch timings on equipment.

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.

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

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

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

A 1/8 inch hole in

steam main can waste

15 tons of coal or 9

tons of fuel oil per

year.

Valve Leakage

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.

Steam is venting to the atmosphere

No Steam Trap / Group Trapping in Vertical Cylinder Dryer

General Practice in Vertical Dryers

Group trapping

4 bar(g)

Over heated

+ excess dried cloth

Recommended Hookup – Vertical Dryers

Existing Hookup – Soft Flow

Recommended Hookup –

Typical Steam Circuit:

Pan Pan

Boiler

Feed Pump

Feed Tank

Make-up Water

Vat

Condensate

Condensate

Steam

Steam

Steam Process Vessel

Space HeatingSystem

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

Steam use in process – 60%

Different losses – 40%

Steam Generation

Two things are directly effect boiler steam generation –

- Boiler operating pressure & Feed water temperature

Poor boiler efficiency due to-

Fluctuating loads – improper loading on the boiler which can be

addressed by proper boiler selection, capacity, burner turndown, etc.

Absence of diagnostics to take corrective action – 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.

Cost of a Boiler – Oil/Gas fired

Steam to Fuel Ratio

Radiation

FuelFlow

Burner

Losses•Stack

•Enthalpy•Un Burnt

Boiler

Draft

Blow down

SteamFlow

Air

BOILER HOUSE DIVISON

What affects Fuel Bill?Excess Air %Feed Water

TemperatureStack temperatureUn burnt lossesNumber of On-OffsScaling on tubesSoot DepositionBlow down TDSMoisture in Fuel

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

Deviation in 2% oxygen Results in 1.5 % Excess Fuel Consumption

10 % Excess Blowdown will amount to 2 % Excess Fuel Consumption

Factuals

Boiler Efficiency Monitoring System

Radiation

FuelFlow

Burner Boiler

Draft

Blow down

SteamFlow

Air

In DirectEfficiency

= 100 - { + }+

+

Losses•Stack

•Enthalpy•Un Burnt

Boiler Efficiency

Fuel Scope for savings (%)

Gas 11.2 %

Liquid 11.8 %

Solid 17.1 %

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

• No boiler is an exception

Conclusion

Steam Distribution

High distribution loss across plants on

account of -

o Improper line sizing

o Improper insulation

o Improper line routing & condensate removal from steam lines

These losses can be addressed by -

o Proper 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.

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 as pipes, 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, thereby operating 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

Pipe Sizing

• Greater Cost• Greater Heat Loss• Greater Volume of Condensate

Formed

• Lower Pressure to Steam Users• Not Enough Volume of Steam • Water Hammer and Erosion

Waterhammer

Sagging Main

Slug of water from condensate

Vibration and noise caused by

waterhammer

Condensate

Relaying to Higher Level

SteamRelayto highlevel

Drain Points

30 - 50m

Fall 1/250

Steam Flow Flow

Proper Condensate Drain

Condensate

PocketSteam Trap Set25/30m

Cross Section

Cross Section

Steam Trap Set

Steam Flow

Steam Flow

• Correct

• Incorrect

Branch Connections

CorrectIncorrect

Steam Steam

Condensate

Drainage of Condensate from Steam Line

Steam Flow

Separator

Fig. Temperature profile across a heat exchange surface

Importance of Moisture Separator

Steam Utilization

Steam Trapping - o In most plants, trap selection is an issue on heating applications.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.

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%

Ball Float Trap:Ensures proper removal of condensate from the process as soon as it forms. Recommended for process application.

Condensate & Flash Steam Recovery

o Huge 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.

* This calculation is made for diesel fired boiler. Similarly it can be done for gas fired boiler.

 

oCondensate water contains 20% energy of steam. Returning condensate

improves the feed water temperature and thus lowers fuel bill.

o Returning 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.

o It 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%.

Benefits of Condensate Recovery:

Energy Content in Dye Liquor Not considering losses the Process Heat Recovery in Dyeing m/c

45 %

15 %

Dye Bath LiquorCooling Water

Energy Content

Benefits of Dye Liquor Heat Recovery

o Recover heat from dye liquor 60~80 deg C from the dyeing

machine. Savings up to 15% in steam used for hot water preparation.

o Pre-heats process water to the dyeing machine. 1-2 extra batches

per week possible.

o Facilities low temperature discharge to ETP. Helpful for effluent

treatment.

o Eliminates pressure fluctuation of boiler.

Dye Liquor Heat Recovery System

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

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

Encon Opportunities

Boiler Efficiency Monitoring

Waste Heat Recovery Boiler from Generator

Thermic Fluid Generator-Efficiency % optimisation

Hot water from DG set Jacket

Optimization

Waste Management

Heat Recovery

(7-8%)

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

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.

Copyright Forbes Marshall, 2006-07

One of Many Successes in Bangladesh!!Cutting

Down

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.

Copyright Forbes Marshall, 2006-07

One of Many Successes! Cutting

Down

CostsIndustry Textile Processing UnitLocation Madhya PradeshSteam Usage In Process eqpt – Stenters, Back filling

M/cs, Calendar M/c etcFuel Wood

The objective - Improve SPFC from 0.33 kgs wood/mt cloth (Rs 0.66/ mt cloth).

Energy conservation recommendations implemented by customer -optimized fuel management – sizing. -Optimized steam generation-undertook better management of process like temp control. -optimized waste heat recovery -reduced losses on account of inappropriate / in-operational trapping

The Results?

0.27

0.28

0.29

0.3

0.31

0.32

0.33

0.34

Pre Audit Post Implementation

Kg

/Met

er c

loth

0.54

0.56

0.58

0.6

0.62

0.64

0.66

0.68

Rs/

Met

er c

lothThe SPFC came down to

0.28 Kg Wood/ Mt Cloth (Rs0.58/MtCloth)!!

One of Many Successes!

CuttingDown

CostsIndustry Textile Processing UnitLocation GujaratSteam Usage Yarn Dyeing M/csFuel 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

One of Many Successes!

CuttingDownCosts

One of Many Successes!

CuttingDownCosts

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!

Bangladesh Office Address:

3rd Floor, Rupsha Tower, Kamal Ataturk Avenue,

Road -17, Banani C/A, Dhaka.

Email: bangladesh@forbesmarshall.com

Website: www.forbesmarshall.com

Thank You