The air staging technology is useful to form reduction zone in the pulverized-coal-fired boiler.The high temperature and trace oxygen occur in the reduction zone,where the ammonia injection has a certain effect on controlling NOx emission,as named Reagent Injection in Staged Flame technology.The Chemkin software was used to investigate the elementary reaction system of NH3-NOx.The research results include:1)the simulation results of Chemkin are in good agreement with the measured data in four reported literature.2)With the decrease of O2 concentration in flue-gas,the temperature window of NH3-NOx reduction reaction is inclined from 800-1150℃ to 800-1600℃.3)There are three key reactions of high-temperature SNCR,e.g.CO2+H=CO+OH,OH+NH3=NH2+H2O,NH2+NO=NNH+OH.Within lower oxygen atmosphere,CO2 plays an essential role to start the non-branching chain reactions in higher temperature.The obtained kinetic description could be used in the CFD modeling.
ChemkinNH3-NOx reactiontrace oxygenreaction temperature windowselective non-catalytic reduction