Investigation on optimal active layer thickness and pore size in dual-layer NH3-SCR monolith for low SO2 oxidation by numerical simulation

Nitrogen oxides (NOx) and sulfur dioxide (SO2) are common gaseous pollutants in the flue gas of stationary resources, such as thermal power plants. The undesired oxidation of SO2 on the catalytic monolith for Selective Catalytic Reduction (SCR) with ammonia will cause deposition of ammonium bisulfate, corrosion and extra pressure drop to downstream devices. A dual-layer model of catalytic monolith was established in this work to thoroughly investigate the effects of active layer thickness on SCR reaction and SO2 oxidation under various operating parameters. Besides, the influences of different sizes of nanopore in catalyst on both reactions are discussed. Thus, optimal parameters and suggestions were given for the design of SCR catalytic monolith with low SO2 oxidation.