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Efficient Operation & Maintenance of Boilers Visakhapatnam, 8th December 2015

Presented by

Organised by

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An appeal to the audience

Topic of this presentation is so vast that it cannot be covered in one session. Due to paucity of time I will only touch upon the important points without going into the depth of the subjects. We will also restrict our discussion within the pressure range of 80 Kg/cm2 because beyond that pressure the subject becomes more complicated. For the same reason I am unable to take questions in the middle of the presentation. Those who have queries please note down the slide number and ask your questions after the presentation is over.

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About the presentation

Slides: 25

Duration: 40 min

Topic: Typical water and fireside problems in boilers

Best operating practices for LP, MP, HP boilers

Chemical treatment for both water and fireside

Role of Ion Exchange (India) Ltd.

Narrator: Supratim Bhowmick

Divisional Manager (Chemicals Division)

Ion Exchange (India) Ltd. 03

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Supratim Bhowmick Divisional Manager (Chemicals)

Ion Exchange (India) Ltd.

Over 8 years in Ion Exchange.

Product Manager for all boiler

chemicals. Over 25 years of

experience, mostly in speciality

chemicals. Special expertise in

boiler water treatment. Also in

reverse osmosis, flocculants and

papermaking chemicals. Email: supratim.bhowmick@ionexchange.co.in

Mobile / WhatsApp: (+91) 933 032 55 66

About me

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Low Pressure Boilers

Typical system configuration and problems

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1. Upto 10 Kg/cm2 pressure, usually upto 10 TPH capacity

2. Firetube or watertube, fixed or travelling grate, rarely FBC

3. All kinds of fuel - coal, biomass, furnace oil

4. Usually no deaerator, sometimes pre-heater

5. Make up usually by softened water, sometimes RO/DM

6. Steam used for process, directly or indirectly

7. Frequent shut down, often on stand by

8. Hard scale, chemical cleaning almost every year

9. Yellow to reddish and turbid blow down

10. Phosphate/Sulphite type waterside treatment

11. Water treatment gets low priority

12. Soot, corrosion, emission problem in oil fired boilers

13. Clinkering, slagging problem in biomass fired boilers

14. Clinkering, unburnt problem in coal fired boilers

15. Fireside chemical treatment very rare 06

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Low Pressure Boilers

Best practices and chemical treatment

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1. Idle boilers corrode faster. Do wet preservation.

2. Recover maximum amount of condensate.

3. Monitor condensate recovery by temperature and TDS

4. Increase BFW temperature above 90 degree Celsisus

5. Dose sulphite continuously, avoid slug dosing

6. Dose phosphate directly in the drum, not in the feed tank

7. Be alert about hardness slippage just before regeneration

8. Maintain 10-15 ppm PO4/SO3 residual, avoid overdosing

9. Filming amine treatment is a good alternative

10. Blow down water should be clean and colourless

11. Rely more on prevention than regular acid cleaning

12. In oil fired boiler use fuel additives to improve efficiency

13. In biomass fired boiler use fuel additive to avoid deposits

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Medium Pressure Boilers

Typical system configuration and problems

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1. 15 – 30 Kg/cm2, usually upto 25-30 TPH capacity

2. Usually combined with back pressure or extraction turbine

3. Equal population of FBC and grated boilers

4. Invariably solid fuel fired – coal or biomass

5. Almost always with deaerators though not properly run

6. Make up with DM or RO water often with MB unit

7. Prolonged run with seasonal shut down for maintenance

8. Less scaling and more corrosion, turbine deposit common

9. Process condensate contamination quite common

10. Usually Phosphate/Hydrazine/Amine treatment

11. Water treatment does not get its due importance

12. Fireside deposit in biomass fired boiler quite common

13. Inadequate combustion is a problem in coal fired boilers

14. Fireside treatment is not so common but picking up 10

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Medium Pressure Boilers

Best practices and chemical treatment

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1. Know your system well, prepare a complete flow chart

2. Identify sources of contamination and plan crisis control

3. Be careful about make up water quality, specially silica

4. Ensure that deaerator always gets adequate steam

5. Ensure that steam is seen coming out of the deaerator vent

6. Do not use sulphite above 25 Kg/cm2 pressure

7. Dose phosphate only in the drum, never with feedwater

8. Do not overdose phosphate to elevate drum pH

9. If drum pH dips immediately use caustic and plug the hole

10. Filming amine treatment is a good alternative

11. Educate your chemists on proper sampling and testing

12. After prolonged shut down flush well before taking load

13. Try to avoid sudden surges in boiler water drum level

14. Do not try to extract more steam than the turbine is designed

15. Biomass fired boilers can benefit from fireside chemicals 12

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High Pressure Boilers

Typical system configuration and problems

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1. Anything above 45 Kg/cm2, but practically above 60 Kg/cm2

2. 80 – 120 Kg/cm2 should be treated in a different category

3. Usually combined with extraction or condensing turbine

4. Cogen and CPP are majority, IPP a new category

5. Mostly AFBC, some CFBC, some WHRB, large ones are PF

6. Mostly coal fired, some smaller units biomass fired

7. Always with perfectly functioning deaerators

8. Make up with best quality DM-MB water

9. Continuous run, hardly any planned shut down

10. Phosphate, Hydrazine, Amines are common treatment

11. Excellent control on water chemistry

12. Still problems occur due to lesser know factors

13. Usual problems are tube failure and turbine deposit

14. Fireside clinkering and slagging is also not uncommon

15. Fireside treatment is still rare though picking up. 14

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High Pressure Boilers

Best practices and chemical treatment

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1. In HP power boilers steam quality is the prime objective

2. Need a water treatment specialist to manage such boilers

3. Measure steam silica, sodium, cation conductivity and dryness

4. Occasionally measure dissolved oxygen offline in feedwater

5. Measure both dissolved and total iron in condensate

6. Those having ACC be very careful about iron oxide fouling

7. Use of alternative oxygen scavenger like DEHA is beneficial

8. Be very particular about phosphate residual. Never overdose

9. Above 80 kg/cm2 follow equilibrium phosphate treatment

10. Cogen boilers should avoid sudden surge in the drum level

11. Occasional wet steam purging of the turbine can be helpful

12. All Amine Treatment is a good alternative for CPP boilers

13. AFBC boilers should be careful about bed coil failures

14. Avoid quick firing to avoid short term failure of wall tubes

15. Any pressure part failure must be examined to avoid repetition 16

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High Pressure Boilers

A few typical problems

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Caustic gouging from steam blanketing

Boiler tube metallurgy is selected on the basis of flue gas temperature outside and water temperature inside. If any boiler tube is water-starved for a prolonged period its metal temperature increases abruptly and it fails. Semi horizontal bed coils frequently fail at 12-O-colck position due to steam blanketing. This does not happen in vertical tubes. 18

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Caustic gouging from iron fouling

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Short term overheating

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Oxygen pitting

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Turbine deposit

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Back firing due to fireside deposit

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Fireside deposit from superheater

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How we can help

Ion Exchange (India) Ltd. are a leading technology

partner in the field of water management. It is one of the

very few companies worldwide who have the complete

product range in this field. Our knowledge is our biggest

asset and that is at your disposal. Feel free to contact us

whenever you need our assistance.

For your boilers we have our INDION brand of waterside

and fireside treatment chemicals.

We also have our EASYTEST brand of mobile test kits

ideal for your labs. 25

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Thank you for your attention !! Questions?