Comparative techno-economic assessment of methanol production via directly and indirectly electrified biomass gasification routes

Abstract

The sustainable production of chemicals and fuels is a major challenge in order to reduce greenhouse gas emissions and reduce the usage of fossil resources. Biomass gasification with a subsequent conversion of the syngas to methanol is an established route. The direct (electrical resistance heating) or indirect (H2 production via water electrolysis and addition to process) electrification of this route with utilization of renewably produced electricity can improve the effective utilization of biomass which is a scarce resource. Starting with a base case (Biomass-to-MeOH), 10 scenarios with different types and points of electrification are modelled in Aspen Plus to generate mass and energy balances. Based on the generated data, the processes are compared in terms of efficiency, economics, and CO2 emissions.The electrification ratios range from 0.12 for the Biomass-to-MeOH process to 1.31. Electrification can increase the carbon efficiency from 43 % for the Biomass-to-MeOH process to up to 95 % while the energy efficiency ranges from 54.6 % to 60.3 % with 54.7 % for the Biomass-to-MeOH process. The levelized cost of methanol ranges from 642 to 795 €/t. Lowest LCOM are reached for direct electrification of the gasifier or reformer. A flexible operation of the electrified process shows a higher sensitivity on the levelized cost for scenarios with high degree of electrification. The marginal emission factor for the used electricity ranges from 1761 to 352 g CO2/kWh to reach equal emissions than the fossil equivalent. Sustainable methanol can be produced with the electrified processes. Especially direct electrification can improve the efficiency and lower cost in comparison to indirect electrification. A combination of both types of electrification is advised if a high product yield and carbon efficiency are desired.