DESIGN-MODEL FOR SELECTIVE CATALYTIC REDUCTION PROCESS - SOLUTION OF CONVECTIVE DIFFUSION AND NOX REACTION

A simple model for the design of selective catalytic reduction (SCR) p rocess is presented. The two-dimensional mass transfer equation shown in Bai and Chwu (1997) is simplified and the analytic solution is obta ined. The analytic solution is verified by the solution of the numeric al two-dimensional model as well as published experimental data. Then it is applied for the design of the SCR reactor. Effects of operating temperature, inlet molar ratio of NH3/NO, channel pitch, and gas flow rate on the SCR reactor volume are evaluated based on a designed NO re moval efficiency. The NH3 slip problem of a given inlet ratio of NH3/N O also is discussed. It is shown that the injection ratio of NH3/NO mu st be slightly higher than the desired NO removal efficiency so that t he reactor volume can be reduced and the problem of NH, slip is not a major concern.