Techno-economic assessment of the one-step CO2 conversion to dimethyl ether in a membrane-assisted process

This study investigates the impact of the membrane reactor (MR) technology with in-situ removal of water to boost the performance of the one-step DME synthesis via CO2 hydrogenation at process scale. Given the higher efficiency in converting the feedstock, the membrane reactor allows for a remarkable decrease in the main cost drivers of the process, i.e., the catalyst mass and the H2 feed flow, by ca. 39% and 64%, respectively. Further-more, the MR-assisted process requires 46% less utilities than the conventional process, especially in terms of cooling water and refrigerant, with a corresponding decrease in environmental impact (i.e., 25% less CO2 emissions). Both the conventional and MR-assisted plants were found effective for the mitigation of the CO2 emissions, avoiding ca. 1.4-1.6 tonCO2 /tonDME. However, given the higher reactor and process efficiency, the membrane technology contributes to a significant reduction (i.e., 25%) in the operating costs, which is a remarkable improvement in this OPEX intensive process. Nevertheless, the calculated minimum DME selling price (i.e., 1739 euro /ton and 1960 euro /ton for the MR-assisted and the conventional process, respectively) is over 3 times greater than the current DME market price. Yet, with the predicted decrease of renewable H2 price and a zero-to-negative cost for the CO2 feedstock, the MR-assisted system could become competitive with the bench-mark between 2025 and 2050.

Automated summary

This study investigates the impact of membrane reactor technology with in-situ removal of water on the synthesis of DME via CO2 hydrogenation. The membrane reactor allows for a significant decrease in catalyst mass and H2 feed flow, as well as a reduction in utilities and CO2 emissions. The membrane technology contributes to a remarkable improvement in operating costs, although the current DME market price is much lower. However, with predicted decreases in renewable H2 price and zero-to-negative cost for CO2 feedstock, the membrane-assisted system could become competitive in the future.