Catalytic methanation of CO2 in biogas: experimental results from a reactor at full scale

In a future energy scenario without fossil fuels carbon from renewable biomass will be a limited resource. Full carbon utilization through catalytic methanation of CO2 in biogas appears to be a low hanging fruit. However, concerns on catalyst cost and wear, elaborate reactor cooling requirements and significant costs related to post-treatment are reported from theoretical studies and early demonstration plants. In this study, we show how a full scale methanation reactor can be operated under favourable process conditions for 1000 hours without complications. We find that operating the reactor at a sub-stoichiometric ratio of 3.9 is optimal in order to deliver pipeline quality gas. The temperature profile shows how start and stop can be performed within minutes, and the combined studies presented are a breakthrough in direct catalytic upgrading of biogas ready for industrial scale implementation.