Acetylene Abatement Over Micro/Mesoporous Active Carbon-Supported Low-Mercury Catalysts

Abstract

A series of low HgCl2-supported catalysts (K-TX-O, K-WG-O, K-S20-O, K-S40-O, K-Fe0.8-O, K-Fe0.8-M, D-Fe0.8-M) was prepared and investigated for C2H2 catalytic abatement during highly purified HCl (HP-HCl) production process. The samples of D-Fe0.8-M, K-Fe0.8-M, and K-Fe0.8-O were found to exhibit much higher activities and better thermal stabilities than those of other samples. The characterization results of XRD, N2 adsorption/desorption, SEM, back scattered electron (BSE) and thermogravimetry (TG) revealed that: (i) the larger mesoporous volumes constituted one of the key factors leading to superior catalytic performances of D-Fe0.8-M, K-Fe0.8-M, and K-Fe0.8-O, which greatly facilitated better dispersions of the loaded HgCl2 species in comparison to other samples; (ii) the KCl additive could further improve the dispersions and thermal stabilities of the loaded the HgCl2 species due to the strong interactions between KCl and HgCl2 species, resulting in relatively higher catalytic behaviors of D-Fe0.8-M and K-Fe0.8-M than that of K-Fe0.8-O; (iii) the KCl/HgCl2 step-by-step loading strategy, wherein the KCl was initially loaded on the Fe0.8-AC substrate thereafter followed by HgCl2 loading, could further improve the catalytic behavior for D-Fe0.8-M due to additional improvements of HgCl2 dispersions. The deactivation and reactivation of D-Fe0.8-M during HP-HCl were also investigated, which suggested that partial deactivated D-Fe0.8-M by C2H3Cl accumulation could be efficiently reactivated by HCl treatment at T = 220 °C.