Design of a Renewable Methanol Production Process from Biogas: Analysis of the Influence of the Operating Pressure in the Synthesis Loop

This study presents the design and analysis of an energy-integrated process for producing green methanol from biogas. Emphasizing the need for sustainable fuel solutions, the paper explores the use of biogas, purified to biomethane, as a feedstock for methanol synthesis. The process involves a convective reformer with bayonet-type tubes for syngas production and a multitubular methanol synthesis reactor. The integration of thermal energy is a core feature, ensuring the process is self-sufficient. Key aspects analyzed include the impact of methanol synthesis loop pressure (30–90 bar) on performance metrics such as carbon and energy efficiency and CAPEX/OPEX of the loop. An optimum operating pressure of 40 bar was found. Simulation results indicate high methane conversion in the reformer (87.34%) and effective internal heat recovery due to the bayonet-type tubes (19%). The overall process achieves a carbon efficiency of 48.5% and an energy efficiency of around 64%.