Coupled Biomass Gasification and Clean Hydrogen for Methanol Production

Methanol is an extremely useful and versatile feedstock in both the chemical and energy industries. It serves as a building block for the production of plastics, synthetic rubbers, and textiles, as well as synthetic diesel and jet fuels. As such, global demand for methanol is high, estimated at approximately 120 million metric tons per year. Current methanol production relies on coal and natural gas as carbon sources, emitting large amounts of carbon dioxide and exacerbating the ongoing climate crisis. Furthermore, these feedstocks are non-renewable. Therefore, developing methanol production routes that utilize renewable carbon sources and maintain a low carbon footprint is attractive from both environmental and long-term sustainability perspectives.

One such route utilizes biomass and water as a source of syngas to feed a reactor. From a stoichiometric standpoint, carbon efficiencies cannot exceed 67%, and in practice they are often substantially lower. As a result, a biomass-to-methanol pathway will necessarily produce a significant amount of CO₂. Another methanol production route that utilizes renewable carbon sources is the "E-methanol" pathway. This approach employs an electrolytic water-splitting process to produce "green" hydrogen, which is then fed into a catalytic reactor along with CO₂ to selectively produce methanol.

Because the E-methanol process is energy-intensive, biomass conversion to methanol generates large quantities of CO₂, and carbon capture technologies are already available and continuing to mature, we propose a combined synthesis approach. Herein, we design a modular process in which CO₂ generated from biomass gasification and methanol synthesis is captured and fed into an e-methanol process. Such facilities can be deployed in regions with abundant biomass and renewable energy resources. In this way, agricultural waste can be upcycled, and excess renewable electricity can be stored in chemical form without reliance on battery storage.