Renewable Methanol Synthesis through Single Step Bi-reforming of Biogas

Biogas is considered a renewable source of carbon for methanol production. For this, biogas, containing mainly CH4 and CO2, is first reformed into syngas (a CO/H2 mixture) followed by conversion to methanol. Conventional reformers, however, require additional upgrading steps to adjust the H2:CO ratio in syngas to 2:1; ideal for methanol synthesis. We formerly introduced the concept of bi-reforming that provides the ideal H2:CO ratio by combining dry and steam reforming in one stage without the need for additional syngas ratio adjustments. Based on these experimental bi-reforming findings, we have now developed a thermodynamic model to determine the optimal conditions for the highest possible carbon conversion and minimum coke formation. The proposed process based on bi-reforming was found to be an efficient alternative, delivering the ideal H2:CO ratio of 2 for methanol synthesis with no coke formation (a common challenge in conventional reformers) and complete carbon conversion at atmospheric pressure and temperatures of around 900 °C.