Influence of H2O on Kinetics of Low-Temperature SCR of NO by NH3 over V2O5 /AC Catalyst

• 1、College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029
• 2、College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029

Abstract：The AC (activated carbon) supported V2O5 (vanadium pentoxide) (V2O5/AC) catalyst shows high activities for selective catalytic reduction (SCR) of nitrogen oxide (NO) by ammonia (NH3) at 393-473 K after a pre-sulfated step. But the activities decrease obviously when adding H2O to the flue gas. The influence of H2O on intrinsic kinetics for this catalyst was first investigated in the absence of internal and external diffusions in a fixed-bed micro-reactor. Then, both the mechanical (i.e. Eley-Rideal model, Langmuir-Hinshelwood model, and Mars-van Krevelen model) and empirical (i.e. first-order model and power-rate law model) models were applied to correlate the experimental data. The results showed that the SCR of NO by NH3 over V2O5/AC catalyst follows the Eley-Rideal mechanism rather than Langmuir-Hinshelwood or Mars-van Krevelen mechanism whether H2O is contained in the flue gas or not, and the pre-exponential factor decreases and activation energy increases with the increasing amount of H2O. Finally, the intrinsic kinetic models obtained in this work were incorporated into a 3D mathematical model of monolithic reactor, and it was found that the Eley-Rideal model is more suitable for describing the SCR of NO by NH3 in the presence of H2O than the empirical models and thus should be adopted in the actual reactor design and scale-up for controlling the emission of NOx.

Keywords： Kinetics Selective catalytic reduction (SCR) V2O5/AC catalyst Monolithic reactor Mathematical model