An integrated CCU-plant scheme and assessment for conversion of captured CO2 into methanol

Abstract The purpose of this work is to highlight the interest of CO2 conversion into MeOH through a complete assessment of the entire CO2-to-MeOH chain. A CO2 capture unit using MEA solvent is considered to treat the CO2 from a 600-MW power plant, and the captured CO2 is then sent to the CO2 conversion unit. As a result, the combination of the two units leads to the integrated CO2 capture and utilization (CCU) plant, in particular involving the reuse of the heat from the high-temperature flows of the exothermal CO2 conversion reactions for regeneration of the CO2 capture solvent, and the recovered H2O between the CO2 capture and conversion units is also proposed to completely fulfill the H2O make-up. The technological results suggest that the integrated CCU plant is expected to offer advantages. The integrated CCU plant studied can utilize ~17.3% of the CO2 emissions of a power plant and convert 92% of them to 59.96 t of MeOH, and the heat integration corresponds to a 41.84% reduction in total reboiler load for the regeneration of MEA solvent. An economic assessment is proposed to estimate the OPEX and CAPEX costs, as well as the net present value, which confirms that the feasible economic conditions strongly depends on electricity costs. The contribution of the process or flows from CCU plant to the main environmental impacts is finally determined using the LCA method. The integrations inside the CCU plant offer a significant reduction in impact categories and CO2 emission as well as non-CO2 emission impacts when compared to the conventional MeOH production process.