Carbon capture utilization through a novel multistage configuration for dimethyl ether synthesis

The conversion of carbon dioxide (COQ) into dimethyl ether (DME) represents a promising alternative in the field of Carbon Capture and Utilization (CCU) processes. In this paper, a novel multi-stage Condensation-Enhanced Carbon Utilization (multi-CECU) process was modeled and simulated with the objective of contributing to the ongoing efforts in process intensification. The efficacy of six distinct arrangements, including the single-stage configuration, was examined to assess the advantages of a multi-stage synthesis process in terms of DME production, COQ conversion, energetic self-sufficiency and exergy efficiency. More in detail, a thermodynamic and kinetic analysis was first conducted on both Aspen Plus and Matlab to determine the optimal operating conditions and design the reactor. Subsequently, a preliminary assessment was performed to identify the more adequate separation temperature to enhance the production of DME throughout the removal of condensable coproducts after the six configurations were implemented on Aspen Plus. Once assumed the temperature based on a trade-off between productivity and energy expenditures, the five multi-CECU arrangements were benchmarked with the single-stage configuration based on relevant technical performances, energetic self-sufficiency, and exergy efficiency by quantifying the overall and relative improvement associated with the introduction of each individual reaction stage. As a result, the 4-stages configuration revealed the greatest improvement potential, with a CO2 plant conversion of 97.23%, a chemical conversion efficiency to DME of 64.37% and an exergy efficiency of 79.02%. The implementation of heat recovery strategies reduced external heat requirements by nearly 60% and cooling requirements by 40%, highlighting the multi-CECU process as a viable solution for sustainable and reliable energy management.