3D Numerical Simulation of Gas Flow and Selective Catalytic Reduction (SCR) of NO in the Honeycomb Reactor

摘要

Selective catalytic reaction(SCR) of NO_x by ammonia is a very efficient method to reduce the NO_x emission from coal-fired power plants and large boilers. The ammonia is injected into the exhaust gas stream and is mixed NO_x. The mixture passes through the honeycomb-type catalyst bed, where NO_x reacts on the catalyst surface with adsorbed ammonia in the presence of excess oxygen, decomposing into diatomic nitrogen and water molecules, thereby reducing the NO_x level in the exhaust gas. The present study discusses the NO_x reduction mechanism in the honeycomb channel. In this work, 3-dimensional computational fluid dynamics (CFD) simulations are carried out to investigate the effects of the various state parameters on the De-NO_x reaction at the catalyst. Research results showed that the gas temperature, flow velocity and concentration ratio all are important parameters of the NO_x reduction with ammonia in the honeycomb catalyst.