Study on the influence of CaO on NH3+NO+O2 reaction system in pre-calciner

摘要

This paper studied the influence of CaO on NH3+NO+O2 reaction system in pre-calciner.Experiments were carried out in a fixed bed reactor.Influence of CaO on NH3+NO+O2 reaction,NH3 oxidation,NH3 decomposition and NO reduction by NH3 at O2 free condition were studied.NH3 conversion rates and product selectivities were obtained for each reaction condition.It was proved that the influence of CaO on SNCR performance changed with temperature.CaO promoted SNCR performance at 650°C and changed to inhibit SNCR performance when temperature increased above 700°C.CaO influenced the reaction of NH3+NO+O2 mainly by catalyzing NH3 oxidation.NH3 conversion rate and NO selectivity decreased when NH3 concentration increased.Addition of NO into NH3 heterogeneous oxidation had little effect on NH3 conversion rate but decreased NO selectivity.A reaction mechanism for NH3+NO+O2 reaction on CaO surface was proposed.Heterogeneous reaction model of NH3+NO+O2 on CaO surface was established based on the proposed reaction mechanism.Numerical results showed that the reaction model in this paper could predict NH3 oxidation and NH3 +NO+O2 reaction on CaO surface very well.