Conceptual Process Design and Technoeconomic Analysis of an e-Methanol Plant with Direct Air-Captured CO₂ and Electrolytic H₂

Abstract

Carbon-negative electrified production of methanol (e-MeOH) can play a central role in sustainable chemical manufacturing in the coming years. In this context, CO 2 -based methanol synthesis routes solely based on renewable electricity have been proposed. However, the production route via direct air-captured (DAC) CO 2 and green H 2 from water electrolysis (WE) is not industrially available, and in-depth feasibility studies are needed to determine its viability. By designing a 50 kt y –1 e-MeOH production plant based on DAC-CO 2 and electrolytic H 2, we assess the plant’s performance and economic feasibility against the state-of-the-art industrial manufacturing based on natural gas steam reforming. Absorption-based DAC accounts for the highest capital expenditure (CAPEX) of the plant, whereas the proton-exchange membrane WE drives electricity consumption. The adiabatic reactor for the catalytic CO 2 –H 2 reaction is the least cost-intensive section. Thus, the levelized cost of product of e-MeOH in 2050 is expected to be still 3 times that of the current fossil-based MeOH. However, the overall electrified process is carbon negative by consuming 0.64 kg CO2-eq kg MeOH –1, whereas the conventional process releases a significant amount of greenhouse gases. Technological improvement of the DAC unit could increase the competitiveness of the e-process, together with lower electricity prices. Furthermore, sourcing CO 2 from concentrated streams would cut production costs up to equaling a conventional process penalized with a 183 $ t CO2 –1 carbon tax.