Experimental study of NO reduction through reburning/advanced reburning of lignite

Abstract：A multi-function denitration test bed was utilized to study the effect of typical reburning parameters on NO reduction with lignite as reburning fuel,and the promotion of NO removal efficiency by adding ammonia or/and Na2CO3 additives to the reburning zone with lignite as reburning fuel.The research results indicate that the reburning denitrogen efficiency of lignite is relatively high and the denitration efficiency of lignite is 76.5% at the reburn fuel fraction（Rff） of 25% under 1 323 K.The optimum parameters for lignite reburning include reburn fuel fraction of 20%～25%,residence time about 0.81 s,reburn zone stoichiometric ratio of 0.6～0.8 and reburn zone temperature of 1 273～1 323 K.Ammonia can promote the efficiency of NO reduction with lignite as reburning fuel when ammonia is added to the reburn zone,and the denitrogen efficiency of lignite advances reburning by adding ammonia first increases and then decreases with reburn zone temperature increasing.NO reduction of as high as 82.2% can be obtained by lignite advanced reburning.Na2CO3 additives could further promote the efficiency of lignite advanced reburning by adding to the reburn zone.At reburn zone temperature of 1 323 K,the efficiency of lignite advanced reburning increases from 82.2% to 85.9% when 473 mg/m3 Na2CO3 additives is added to the reburn zone.