Catalytic reforming of synthetic biogas for hydrogen enrichment over Ni supported on ZnO[sbnd]CeO2 mixed catalyst

Abstract

Catalytic reforming has been considered as an effective technique to produce hydrogen (H2)/syngas from the various feedstocks. The present study focussed on the dry reforming of biogas with Ni (10 wt %) catalysts supported on ceria (CeO2) and Ni catalyst with mixed support of ceria and zinc oxide (ZnO). The synthesized catalysts were characterized by H2-TPR, FESEM, EDX, XRD and BET techniques. The effect of Zn loading (10 and 20 wt %) on the catalytic activity was assessed with respect to various performance parameters. Increased reaction temperature from 650 °C to 900 °C caused a significant increase in reactant conversion and product yield. At 650 °C, CH4 conversion and H2 selectivity achieved were 18.1 and 5.2%, respectively, whereas, at 900 °C, enhanced CH4 conversion (78.5%) and H2 (35.7%) selectivity was achieved with Ni0.1/CeO2 catalyst. Further, it was observed that Ni supported on mixed support exhibited higher reactant conversions when compared to Ni supported with ceria. At 900 °C, Ni0.10/(Zn0.1-Ce0.9) catalyst showed higher CH4 and CO2 conversion of 83.1 and 97.0%, respectively, with 40.3% of H2 enrichment. Carbon deposition rate in mixed support catalyst was observed to be less when compared to single support material after 7 h of continuous dry reforming reaction. Further, in order to reduce carbon deposition on the catalyst bed, dry oxidative reforming was carried out at 650 °C with varying proportions of O2/CH4 ratio which resulted in significantly higher CH4 conversion with low catalyst deposition.