Ultra-high carbon dioxide capture efficiency in power to methanol concept: Energy, exergy and economic evaluation of amine and methanol-based solvent with hydrogen gas stripping

Abstract

The power-to-methanol concept has gained attention to combat climate change by converting captured CO2 to methanol (MeOH). To provide captured CO2 for MeOH synthesis, studies have focused on utilizing Monoethanolamine (MEA) to capture CO2 from flue gas. However, capturing CO2 using MEA is an energy-intensive process. Here, an alternative capture process employing MeOH as a physical solvent and H2 as a stripping gas is utilized to capture over 99 % and minimize energy consumption in the recovery column. The captured CO2 is then converted into MeOH. Aspen Plus V12.1 is utilized for developing the power-to-methanol process. Specifically, comprehensive analysis for the CO2 capture column using a rate-based model is conducted for both solvents. The total duty required for MeOH-based solvent is calculated to be 6.336 MJ(electric)/kg CO2, while for MEA-based solvent, it amounts to 15.959 MJ (steam)/kg CO2. Total exergy loss is reduced by 66.71 % compared to the MEA-based solvent process. Additionally, by using heat integration on the MeOH-based process the cost reduction can be pushed more from reducing the cost by 19.14 % compared to the MEA process to reducing 23.63 %. These findings highlight energy savings and cost reduction for promoting a more sustainable and economically viable approach to addressing climate change.