Biomass-to-Methanol by dual-stage entrained flow gasification: Design and techno-economic analysis based on system modeling

In recent times, methanol production has been significantly augmented in energy and chemical industries as it is an essential molecule for chemical synthesis and other utilities such as clean transportation fuel. However, the most preferred Coal-to-Methanol (CTM) production platforms in current China's industries are facing severe obstacles in energy as well as water consumption, and pollutant emissions. Herein, this work provides a conceptual design and modeling of a high efficient Biomass-to-Methanol (BTM) process. It involves the configuration of biomass pre-pyrolysis followed by entrained flow gasification, which avoids separate torrefaction of feedstock, and provides higher gasification temperature as well as cold gas efficiency. The addition of steam and CO2 into gasification and the application of slurry-phase synthesis reactor also improved the methanol yield to 18.5 mol/kg dry biomass. The overall biomass consumption of this system is only 1.99 t/t methanol, and an exergy efficiency of about 70% is achieved through energy integration. The water consumption and CO2 emission of this BTM process are much lower than conventional CTM, indicating better resource utilization efficiency as well as environment-friendly nature. The production cost of this BTM is approximately 2056-2284 CNY/t methanol (i.e. 302-336 USD/t) which is about 20% higher than CTM and close to Natural Gas-to-Methanol. So, reducing production cost is the priorities to be considered for the BTM development. The forthcoming carbon tax can also improve the economic competitiveness of BTM, especially when the carbon tax is higher than 100 CNY/t.