Controlling boiler emissions in an industrial cluster-A case study

1. Controlling boiler emissions in an industrial cluster-A case study Prof. H S Syed Asst. Prof. of Env. Engg L. D. College of Engg, Ahmedabad November , 2011

2. Chimney, the stack attached to the boiler house. • A symbol of progress and development in the past • Now, a symbol of pollution and hence a concern

3. Heat requirements in the industry are satisfied by steam generated at boiler house. • Boiler House - an important source of air pollution. • Different types of boilers, of different capacities using different types of fuel with different operating conditions are in use.

4. Case Study: • Narol Industrial cluster of textile process houses • was identified as a major source of pollution by • Supreme Court appointed Environmental Pollution Control Authority(EPCA) – Bhurelal Committee. • Also identified by GPCB as major air polluter with reference to CEPI (Comprehensive Environmental Pollution Index ) score of MOEF .

5. Environmental Engg Department , L D College of Enginering , Ahmedabad was approached by Ahmedabad Textile Process Association (ATPA) to study the problem and provide a solution to pollution.

6. Case Study: • Narol Industrial cluster of textile process houses • 122 Process Houses • 91 having Steam Boilers and Thermic Fluid Heaters • 87 have been surveyed and data collected

7. Broad Classification Of Boilers Based On Steam Generation Capacity

8. The Different Fuels Used In The Boiler

9. The common fuels used are wood for ≤ 2 Ton/hr and lignite for ≥ 5 Ton/hr capacity boilers. The Proximate Analysis Of The Fuel

10. The common air pollutants encountered: PM, SO2 & NOx • The air pollutants namely particulate matter (PM), SO2 and NOx primarily depend on the fuel used as well as on the operating conditions and procedures adopted.

11. Based on the proximate analysis stoichometry calculation for pollutants (50% Excess Air)

12. Out of 87 - 30 selected units were monitored for air pollution parameters. The Measured Concentration Of Pollutants

13. The present scenario: About pollutant control equipments/ systems; • Practically all boilers are equipped with multi cyclones • Not designed appropriately • Offers only 30- 35 % removal of PM

14. ≤ 2 Ton/hr: No economizer or pre-heaters are installed to control temperature • ≥ 5 Ton/hr: Economizer or pre – heaters are installed for heat recovery and hence temperature control • Bag filters are installed at practically all the units. • Under compulsion and directions of Bhurelal committee and GPCB

15. The boilers with steam generation capacity ≥ 5 Ton/hr, mostly use lignite as fuel. • Lignite generates PM and SO2. • Wood generates PM • However, no system is installed to control SO2 in the flue gas.

16. The multi cyclones and bag filters installed are not appropriately designed and hence are neither adequate nor efficient • Result is gross non - compliance of the emission standards.

17. Environmental Engineering Department of L.D. College, Ahmedabad has proposed/ developed the scheme • Design Approach: • For ≤ 2 Ton/hr capacity wood/saw dust as fuel • Multi cyclone – Venturi Scrubber– Cyclone separator-Demistifer • For ≥ 5 Ton/hr capacity lignite as fuel • Multi cyclone – Bag Filter – Packed bed Alkali wet Scrubber

18. 8 1 2 3 4 6 7 10 12 5 11 5 • Venturi Scrubber 7. Filter Cloth • Cyclonic Separator 8. Mesh Pad Type Demister • ID fan 9. Alkali storage tank (powder / lye) • Stack 10. Feeder • Filter neutsch 11. Mixing tank • Alkali Recirculatin Pump 12. Pump (Alkali Solution) : The Proposed Air Pollution Control System for ≤ 2 TPH Lignite based Boiler

19. The Proposed Air Pollution Control System ≥ 5 Ton/hr capacity: Lignite as Fuel Cyclone Bypass ID Fan Alkaline Wet Scrubber Stack Bag House Furnace Pre Air Heater Multi Cyclone

20. The Expected Results: When installed as per the design and operated as directed the emissions norms will be satisfied.

21. GOD BLESS YOU