STUDY ON NO HETEROGENEOUS REDUCTION WITH COAL AND CHARS IN AN ENTRAINED FLOW REACTOR DURING REBURNING

摘要

The effects of coal types with wide volatile matter including lignite, bituminous coal and lean coal, reaction temperature, coal particle size, the primary-zone stoichiometry (SR1) and reburning zone stoichiometry (SR2), etc. on NO reduction efficiency were carried out systematically in an entrained flow reactor, the heterogeneous NO reduction mechanism was analyzed. The results indicate that the NO reduction efficiencies increase with decreasing of SR2 and coal particle size, and increasing of reaction temperature; The char contributions to the total NO reduction efficiency increase with increasing proximate volatile matter, coal particle size and decreasing of reaction temperature. The char contribution can be reached more than 40% when SR2 is larger than 1.06 or less than 0.92 for XLT lignite. The char contribution at the conditions of SR1=1.0 and SR1=1.2 is significantly larger than that at SR1=1.1 for coals with high volatile at a fixed reburning fraction.