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Table A1.1: Comparison of Combined SO2/NOx Control Processes
Process | Advantages | Disadvantages |
Adsorption/ Regeneration | High-temperature gas is not required High removal efficiency Low volume of wastes Potentially marketable byproduct | Solids recirculation is complex High sorbent costs High flue-gas pressure loss |
Flue Gas Irradiation |
High temperature gas is not required SO2, NOx, and particulate removal in one device Potentially marketable byproduct | High auxiliary power High-cost reagent (ammonia) Potential for secondary emissions (e.g., N2O) Byproduct difficult to dispose of |
Wet Scrubbing Additive for NOx Removal | Easily retrofittable to scrubbers One vessel for SO2 and NOx removal Process chemistry also suitable for high-sulfur coals |
Complex and precise process control needed Wastes contain nitrogen/sulfur compounds Flue-gas reheating may be required |
Gas/Solid Catalytic Operations | No solids recirculation High SO2 and NOx removal Potentially marketable byproduct | High temperature gas
needed Acid collection adds complexity Catalysts must be replaced periodically |
Electromechanical | Mechanically simple One device for both SO2 and NOx removal No reagents needed No high volume wastes | High auxiliary power required High-temperature gas required |
Dry Alkali | High temperature gas not required Easily retrofittable to dry scrubbers | High simultaneous SO2 and NOx removal may not be possible Wastes difficult to dispose of Potential for secondary emissions (e.g., NO2) |
From Technological Alternatives to Reduce Acid Gas and Related Emissions from Energy-Sector Activities in Northeast Asia by David Von Hippel