Biogas reforming for hydrogen production over Ni-Co bimetallic catalyst supported on spherical Al2O3—— Effect of operating conditions

Key words: 
• biogas reforming /
• hydrogen production /
• alumina pellet /
• Ni-Co bimetal /
• operating condition

Abstract: Ni-Co/La2O3- Al2O3 catalyst of biogas reforming with better activity, stability and resistance to carbon deposition was developed in our previous work. In present paper, commercial Al2O3 pellets (4~5 mm) were selected as support and doped with La2O3. The spherical Ni-Co/ La2O3-Al2O3 catalyst was prepared by conventional wetness incipient impregnation. Effect of operating conditions on the performance of the industrial scale catalyst was investigated, feeding with CH4/CO2 volume ratio of 1, which was similar with the composition of biogas. The results showed that low activity of biogas reforming was observed over commercial γ-Al2O3 pellet but very high activity over the spherical Ni-Co/ La2O3-Al2O3 catalyst in the laboratory scale. Higher reaction temperature was beneficial to increase catalytic activity of reforming, but the increasing trend was slow above 800℃. Metal particles tended to aggregate and the deposition of carbon was suppressed at higher reaction temperature. Catalytic activity decreased with the increasing of gas hourly space velocity (GHSV). It was proved that the catalyst reduced at 700℃ for 2 h in pure H2 flow showed smaller metal particle size and lower average coking rate.