Analysis of Industrial Waste Gas SCR/SNCR Technology and Balancing of Reducing Agent Consumption

The industrial waste gas NO_x control technological measures at home and abroad were reviewed, the NO_x emission status from key sources in China analyzed, and the ammonia consumption required for industrial waste gas denitrification estimated. The results show that the annual ammonia consumption is 3.20 million metric tons for the thermal power industry, accounting for 6.3 % of gross annual ammonia production in China, while generating 59 000 cubic meters of waste SCR DeNO_x catalyst annually. The annual ammonia consumption is 0.83 million metric tons for the cement industry, accounting for 1.6 % of gross annual ammonia production. The annual ammonia consumption is 0.96 million metric tons for the industrial coal-fired boilers, sintering kilns, glass kilns and ceramic kilns, etc., accounting for 1.9 % of gross annual ammonia production. The method of recovering NO_x from waste gas as the raw material for producing HNO₃ was evaluated. It was estimated that 0.67 million metric tons of NO_x could be reduced annually for the glass kilns and ceramic kilns, while saving 15 000 cubic meters of SCR DeNO_x catalyst. About 1.65 million metric tons of nitric acid with purity of 50 % could be produced accordingly, thus relieving the serious environmental pollution problems from nitric acid industry.