Bimetallic Ni-Co catalysts for co-production of methane and liquid fuels from syngas

Abstract

With the rapid expansion of the natural gas consumption market worldwide, methanation of coal- or biomass-derived syngas for production of synthetic natural gas (SNG) is gaining considerable interest. In order to solve the problem of natural gas “peak shaving”, adjusting product distribution of the SNG plant is an efficient method to meet the demand fluctuation of natural gas in peak and off season. Herein, the conversion of syngas to SNG (CH4) and co-production of liquid fuels (C5+) over bimetallic Ni-Co catalysts was investigated at industrially relevant conditions. The effects of integration manner of the Ni-Co components, Ni/Co mass ratio, and the operating conditions on the catalytic performance were investigated. Due to the synergistic interaction between Ni and Co, silica supported Ni-Co bimetallic catalyst shows higher activity and total yield of methane and liquid fuels compared to the physically mixed sample. In addition, a good balance between Ni and Co content is crucial for the high efficiency co-production of SNG and liquid fuels. It is found that the optimum operating range in the present study is 550–578 K, H2/CO = 3, 3.0 MPa and W/F = 5 gcat h mol−1, in which more than 80 % total yield of methane and liquid fuels can be obtained on the 2Ni-1Co/SiO2 bimetallic catalyst. Moreover, it shows good thermal stability during the 55 h reaction time. All catalysts were examined by XRD, TEM, H2-TPR and XPS.