Abstract: Based on the mechanism of selective catalytic reduction (SCR) technology, a set of denitrification mechanism modeling equations of regenerator flue gas SCR system in fluidcatalytic cracking unitwere established. According to a large amount data of SCR system, the mechanism model equations were solved by Runge-Kutta-Gill method, and the model parameters were optimized by combining genetic algorithm. The verification results show that the mean absolute percentage error of the model is 5.75% and the coefficient of determination is 0.906, which indicate that the established SCR denitrification mechanism model has strong generalization ability and high simulation accuracy. The model will be expected to play an important role in optimizing the operating conditions of the SCR systems for achievement standard ofnitrogen oxides emission of the treated flue gas.

Key words: selective catalytic reduction, flue gas denitrification, nitrogen oxides, mechanism model, Runge-Kutta-Gill method, genetic algorithm method