Increasing energy demand, volatility in oil prices and a changing climate have necessitated the study of both sustainable fossil and bio-based means of energy and chemical production. Among fossil fuels, natural gas is seen as a cleaner alternative to coal or petroleum and has recently become more available; however, processes that rely solely on natural gas, especially for production of energy and fuels, can still contribute significantly to increasing levels of atmospheric CO2. In order to improve overall carbon neutrality, renewable bio-based resources can be co-utilized with natural gas/methane. The goal of this study is to investigate the effectiveness of syngas production by combining methane reformation with biomass gasification. This was achieved through catalyst characterization and experimental lab-scale reactor testing. Catalysts examined for combined methane reformation and biomass gasification are lab-prepared Ni/Al2O3, Ni-Co/Al2O3 and commercially available Ni-based HiFuel R110 (Alfa Aesar). Catalysts were characterized using successive temperature-programmed oxidation/reduction, EDS and SEM imaging. Fixed-bed catalytic reactor testing was carried out to study reactions between biomass gasification-derived syngas, methane and steam. Experimentally, syngas was shown to increase after reaction (950 C, ~1 atm) to a H2:CO ratio of 1.5 from an initial value of 1.0 with a 71% increase in calorific value. The resulting syngas was virtually free of CO2 and the reactor showed a steady state CH4 conversion greater than 80% during 8 hours time on stream under optimal conditions. Limiting inlet steam to sub-stoichiometric amounts for bi-reformation (3CH4 + 2H2O + CO2 = 8H2 + 4CO) indicated a direct correlation between the final H2 concentration and initial steam concentration. Exit-gas H2 and CO concentrations increased to maximum values of approximately 36% and 25%, respectively, from initial values of 18% each. Carbon deposition on the catalyst surface, based on post-reaction SEM and EDS, appeared to occur as non-deactivating filamentous growth from active sites. These results suggest that methane reformation coupled with biomass gasification is an effective and sustainable tool for both increasing the energy content and controlling the H2:CO ratio of syngas for utilization in downstream applications. Future research should focus on the investigation of mass transfer limitations and reactor conditions to further optimize desired syngas characteristics.

Combined steam and dry reforming of methane over nickel-based catalysts for upgrading biomass gasification-derived syngas

253rd National Meeting (2017)

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