Catalytic steam reforming of toluene as model tar compound using Ni/coal fly ash catalyst

Abstract

Abstract Coal fly ash (CFA), a solid waste from power plants, was selected as the support of Ni‐based catalysts used for steam reforming of toluene in a fixed‐bed reactor. The CFA support was thermally pretreatment first, followed by chemical activation with different treatment time (6 h to 4 days) in 2‐mol/L HNO 3 solution. Then, series low‐cost catalysts were prepared by wet impregnation. The prepared catalysts were characterized suitably by X‐ray diffraction (XRD), Brunauere–Emmette–Teller (BET), temperature programmed reduction (TPR), temperature programmed desorption (TPD), and Raman techniques. According to the catalyst characterization, the chemical pretreatment could improve the support property by adjusting the chemical composition. The Fe‐rich Fe‐Ni and Ni‐Co alloy was formed by H 2 reduction on the Ni/CFA‐6h and Co‐Ni/CFA‐6h catalysts, respectively. In the catalytic steam reforming of toluene, the Ni/CFA‐6h had the best catalytic active among all monometallic catalysts, which could be attributed to the existence of Fe 0.94 Ni 0.06 particles, and its performance could be further improved after partly replacing Ni by Co. The Co‐Ni/CFA‐6h catalyst exhibited the best ability of carbon deposit resistance, implying that its catalytic performance slightly lower than Ni/SiO 2 was due to the too large S BET surface area gap.