Table 2 in ENVIRONMENTAL IMPACT ASSESSMENT (EIA) OF WORLD BANK FINANCED SIDDHIRGANJ 450 MW COMBINED CYCLE POWER PLANT (CCPP) PROJECT SIDDHIRGANJ, NARAYANGAJ

Table 2 - Performance ł Characteristics of Secondary NOx Reduction Systems TypeCharacteristicsPlantCapitalCostIncreaseSCR• NOx emission reduction rate of 80 –4-9% (coal-95%fired boiler)• Use 0.5% of electricity generated• Use ammonia or urea as reagent.1-2% (gas-• Ammonia slip increases with increasingfiredNH 3 /NOx ratio may cause a problemcombined(e.g., too high ammonia in the fly ash).cycle gasLarger catalyst volume / improving theturbine)mixing of NH3 and NOx in the flue gasmay be needed to avoid this problem.20-30%• Catalysts may contain heavy metals. Proper handling and disposal / recycle(reciprocating engines)of spent catalysts is needed.• Life of catalysts has been 6-10 years(coal-fired), 8-12 years (oil-fired) andmore than 10 years (gas-fired).SNCR• NOx emission reduction rate of 30 –1-2%50%• Use 0.1-0.3% of electricity generated• Use ammonia or urea as reagent.• Cannot be used on gas turbines or gasengines.• Operates without using catalysts. Source: EC (2006), World Bank Group