Kinetic study of selective catalytic reduction of NO by NH₃ on Mn-Fe/DPC catalyst

Abstract

Mn-Fe/DPC were prepared by precipitation. The intrinsic kinetics model for Mn-Fe/DPC catalyst was investigated with little internal and external diffusion influence by the way of steady-state dynamics from 120℃~180℃. The apparent activation energy and the reaction order to NH3, NO and O2 was also promoted. The results showed that the initial concentration of NH3 has little effect on the conversion rate of NO, which could be attributed to the rapid adsorption of NH3 on the catalyst surface. Meanwhile, the conversion rate of NO increased with initial concentration of NO and O2, indicating that NO and O2 reacted mainly in gaseous state.The results indicated that the conversion rate of NO increases with initial concentration of NO and O2, NH3 is absorbed and activated quickly on the active sites of catalyst surface. The NH3-SCR reaction over Mn-Fe/DPC exhibits first-order with respect to NO, zero-order to NH3, and nearly 0.39-order to O2 at 120℃~180℃, thus the equation for the NO conversion rate is rNO=k[NO] [O2]0.39. The apparent activation energy of catalyst is 40.25 kJ/mol, which is similar to commercial vanadium-titanium based catalyst and molecular sieve based catalysts with Fe.

Keywords

• dolomite-palygorskite clay(dpc)
• denitration
• kinetics
• selective catalytic reduction(scr)