Eliminating air heater plugging and corrosion caused by SCR/SNCR systems for NOx control on coal-fired boilers
- Paragon Airheater Technologies (United States)
In a typical coal-fired power plant the rotary regenerative air heater is responsible for 5-10% of the boiler's total efficiency. The three biggest threats to air heater performance deterioration are corrosion of the heat exchange surfaces, plugging, and air heater leakage through the seals. The article concentrates on the vastly increased level of corrosion and plugging issues associated with installing selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) systems for controlling nitrogen oxide emissions. Some injected ammonia in the SCR process reacts with SO{sub 2} to form ammonium sulphate and bisulphate (ABS) which is deposited on the air heater element surfaces. This can be overcome by applying coatings, using corrosion-resistant steels, reconfiguring the air heaters to a two layer design, improving air heater blowers, improving technologies for removing ammonia 'slip' before it enters the air heater, and using new catalysts that reduce the oxidation of SO{sub 2} to SO{sub 3}. 4 figs.
- OSTI ID:
- 21004919
- Journal Information:
- Power Engineering (Barrington), Vol. 111, Issue 10; ISSN 0032-5961
- Country of Publication:
- United States
- Language:
- English
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