Synthetic natural gas production from the three stage (i) pyrolysis (ii) catalytic steam reforming (iii) catalytic hydrogenation of waste biomass

Synthetic natural gas (methane) production was systematically investigated by optimizing various operating parameters using a three stage (i) biomass pyrolysis (ii) catalytic steam reforming (iii) catalytic hydrogenation reactor system. Several operating parameters were optimized including catalytic steam reforming temperature, steam weight hourly space velocity (WHSV), catalytic hydrogenation temperature and hydrogen gas space velocity. In addition, the influence of different metal catalysts (Ni/Al2O3, Fe/Al2O3, Co/Al2O3, and Mo/Al2O3), catalyst calcination temperature, catalyst metal loadings, and different catalyst support materials (Al2O3, SiO2, and MCM-41) was carried out specifically to optimize catalytic hydrogenation in the third stage reactor. The highest methane yield of 13.73 mmoles g−1biomass (22.02 g CH4 100 g−1biomass) was obtained with a second stage catalytic steam reforming temperature of 800 °C over a 10 wt% Ni/Al2O3 catalyst and with a steam WHSV of 5 mL h−1 g−1catalyst together with a third stage catalytic hydrogenation temperature of 350 °C over a 10 wt% Ni/Al2O3 catalyst with added hydrogen gas space velocity of 2400 mL h−1 g−1catalyst. [Display omitted] •Novel 3-stage (i) pyrolysis (ii) reforming (iii) hydrogenation developed for CH4•Catalytic steam reforming pyrolysis gases produces COx for catalytic hydrogenation.•Optimized CH4 yield from biomass with Ni-metal and Al2O3, support material•Maximum CH4 yield was 22.02 g CH4 100 g−1biomass.