The promotion effect of Ce on Fe/BEA deNOx catalyst under high water content facing coalbed methane power generation

Abstract

Coalbed methane (CBM) power generation is supposed as the most effective method to make utilization of low-concentration methane, efficient NO_x removal from CBM power generation is of great significance. Distinguished from traditional coal-fired power plants and diesel vehicle, CBM power generation exhaust exhibited the characteristics of high temperature, high NO_x concentration, high humidity, and high gas hourly space velocity, where the new challenges were proposed for NOx removal facing the CBM power generation. Under this background, the series of x wt% Fe + y wt% Ce/BEA denitrification catalysts with different iron and cerium contents (x = 1, 2, 3; y = 0, 1, 2) were fabricated via impregnation method and evaluated in the NH₃-SCR reaction, where the optimized 2 wt% Fe/BEA and 1 wt% Fe + 1 wt% Ce/BEA catalysts were employed to further researched the HTA performance and H₂O resistance under higher water content. The results indicated that the catalytic performance was obviously enhanced after introducing cerium, where the NO_x conversion of 1 wt% Fe + 1 wt% Ce/BEA was above 95 % at 420–600 °C, after hydrothermal aging process, the 1 wt% Fe + 1 wt% Ce/BEA-H still possessed the favorable activity, besides, 1 wt% Fe + 1 wt% Ce/BEA also presented better performance even under the wet conditions. Characterization analysis revealed that the better performance of the 1 wt%Fe + 1 wt% Ce/BEA catalyst originated from the synergistic effects between iron, cerium and BEA support, which was attributed to the appropriate distribution of Fe³⁺ content, redox ability, and the abundant acid sites, thus further leading to the excellent denitrification activity, high N₂ selectivity, and strong water resistance.