Co-processing methane in high temperature steam gasification of biomass

► CH4 and biomass were reacted simultaneously in an entrained flow steam-gasifier. ► Equilibrium accurately predicts the syngas composition at 1500°C; not at 1200°C. ► ANOVA reveals temperature dominates syngas composition and conversion. ► Product syngas composition can be tuned for downstream processing. High temperature steam gasification/reforming of biomass-methane mixtures was carried out in an indirectly heated entrained flow reactor to analyze the feasibility of controlling the output composition of the major synthesis gas products: H2, CO, CO2, CH4. A 23 factorial experimental design was carried out and compared to thermodynamic equilibrium predictions. Experiments demonstrated the product gas composition is mostly dependent on temperature and that excess steam contributes to CO2 formation. Results showed that with two carbon-containing reactants it is possible to control the gas composition of the major products. At 1500°C, the equilibrium results accurately predicted the syngas composition and can be used to guide optimization of the syngas for downstream liquid fuel synthesis technologies.