基于失活商业脱硝催化剂制备的再生SCR催化剂性能研究

NO Reduction Over a Novel SCR Catalyst Regenerated From Deactivated Commercial DeNO_x Catalyst

为了解决燃煤电厂废弃商业SCR催化剂的处理以及充分利用锰基SCR催化剂的低温活性,提出了失活商业SCR催化剂再生的新方法:将失活的商业SCR催化剂作为载体,利用多步浸渍法,将锰氧化物(MnO_x)负载于载体上,制备成新的脱硝催化剂。利用XRF,XRD,SEM,XPS和N_2等温吸附等测试技术对新鲜催化剂、失活催化剂以及再生催化剂进行表征,以探究再生方法制备的催化剂相比失活催化剂带来的变化。结果发现,针对采用的原始失活催化剂来说,MnO_2负载质量分数为4.67%时,催化剂的综合理化性能和催化剂的脱硝活性最优。另外,再生的催化剂在250℃条件下仍然可以保持较高的脱硝活性,说明再生的催化剂具有更宽的活性温度窗口。再生催化剂中起到催化作用的是未中毒的V_2O_5以及负载的MnO_x。MnO_x可能为催化剂带来了低温活性。同时,催化剂在高空速下依然可以保持较高的催化活性。该再生方法不仅可以实现废弃的SCR催化剂的再生,还可以提升催化剂的催化性能。

In order to address the problems of treatment of the deactivated commercial SCR catalysts （DSCR） used in coal-fired power plants and explore the potential of the MnOx-based low temperature catalysts, a new procedure was proposed. In the present procedure, the DSCR served as the catalyst support and MnOx was loaded on it by Multi-step impregnation method. The MnOx-based supported catalyst was used for NO reduction. Characterization of X-ray fluorescence, X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy and N2 isothermal adsorption were conducted to study the properties of the regenerated SCR catalyst. The results indicated that the regenerated sample （RSCR-II） with 4.67 wt% MnO2 on the DSCR exhibited the most superior NO reduction performance. In addition, the RSCR-II showed better NO reduction activity in a wider temperature range compared with that of the unpoisoned fresh commercial SCR catalyst. Two components, MnOx and unpoisoned V205, on the regenerated catalyst were responsible for the NO reduction. RSCR-II also exhibited excellent NO reduction efficiency at high gas hourly space velocity. Therefore, the proposed method can not only well regenerate the deactivated commercial SCR catalyst but also create a better SCR catalyst.