Towards zero CO_2 emissions in the production of methanol from switchgrass. CO_2 to methanol

摘要

In this work an integrated facility is proposed that produces methanol from switchgrass and uses the captured CO_2 to enhance the production capacity by 50% via CO_2 hydrogenation. The process consists of two sections, biomass processing to syngas and its conversion to methanol, and the electrolytic section where hydrogen is produced to hydrogenate the CO_2 that has been captured during syngas cleaning. The integrated facility produces up to 207 Mgal/yr of methanol and 318 kt/yr of oxygen, but requires a large amount of electricity to generate the hydrogen. Thus, it can only be used in regions where wind velocity is above 8 m/s and solar radiation is above 5 kWh/m~2/day such as in the Midwest of US, certain regions in China or in the South of Europe. The investment is high, around 1000 M€, but the production cost of methanol is promising, 0.25-0.35 € /kg with a high production capacity.