Application Of Exhaust Gas Reuse Combined With SNCR Method In Denitrification Of Coke Oven Gas

One of the main energy source is coal in China,and the main pollutants of coal combustion are nitrogen oxides,sulfur dioxide and dust.At present,the flue gas denitrification technology is based on the SCR(high temperature)and SNCR methods.The SCR method(low temperature)is mainly used in coke oven flue gas denitrification technology,while the waste gas reuse and SNCR methods are less studied and applied in this field than the above-mentioned method.Based on the existing coking process and type of coke oven in Jinhui Company,we investigated the heating mode of coke oven,generation mechanism of nitrogen oxides and influence factors,and established the technical route of flue gas denitrification:first controlling the yield of nitrogen oxides in flue gas by using waste gas reuse method and then removing the generated nitrogen oxides by using SNCR method.In order to systematically study the application of waste gas reuse and SNCR methods on flue gas denitrification,we analyzed the relative reaction mechanism,designed the process of flue gas reuse and SNCR,and completed the selection of core equipment,the design of automatic control and the system arrangement of production site,and so on.After technical reform,the large-scale experiment obtained the desired results that the denitrification rate of coke oven flue gas reached above 85%,and the content of NOx in flue gas outlet reached below 150 mg/m3.In addition,the techno-economic appraisal of these experimental results shows that the total investment of flue gas reuse and SNCR methods is ? 4.7 million and the operation cost increase ? 4/ton,and the related investment of fixed assets and operation cost of this method are about a third of that of traditional SCR method.Therefore,this method is worth of popularization on improving the denitrification technology of coke oven flue gas in domestic.