Technical and environmental assessment of renewable dimethyl ether production from CO2 in different european contexts

This work highlights the differences between two dimethyl ether (DME) production pathways from CO 2 : (S1) intensified direct conversion of CO 2 and H 2 via sorption-enhanced DME synthesis (SEDMES) in a single reactor, (S2) indirect conversion in two steps via methanol as an intermediate product followed by dehydration to DME; For this purpose, flue gas from a cement production plant was considered as the CO 2 source and membrane separation (MS) was used for carbon capture, while hydrogen was generated via water electrolysis. ProSimPlus® software, was used for process simulation. Starting from 5,864 kg CO 2 , scenario S2 produces 2,433 kg/h of DME, which is lower than 2,929.5 kg/h in S1. In addition, S1 shows significantly lower electrical and heating energy consumption per kgDME produced: 17.80 kWh and 3.07 MJ, respectively, compared to 22.59 kWh and 10.14 MJ in S2. The environmental analysis was carried out using a comprehensive Life Cycle Assessment (LCA) approach, with the production of 1 kg of high-purity DME defined as the functional unit and compared with the traditional production of DME (S3) from fossil methanol (MeOH). The results show that the electricity source plays an important role in determining the environmental impact in the context of North-West Europe with a focus on the Netherlands. If the SSP2-NDC trajectory is considered, for the Dutch electricity mix, the GWP100 impacts of both scenarios decrease significantly over year (2020–2050). For instance, in S2, GWP100 could decrease from 3.46 kg CO 2 -eq/kgDME in 2020 to −1.41 kg CO 2 -eq/kgDME by 2050 due to planned electricity defossilization in the Netherlands. Same for S1, GWP100 value dropped from 2.08 to −1.63 kg CO 2 -eq/kgDME, indicating climate positive outcomes. However, S3 maintains a stable GWP100 impact of around 1.2 kg CO 2 -eq/kg DME over years, due to its fossil fuel-based nature. This study demonstrated that S1 and S2 offer promising alternatives to the conventional fossil DME production pathway highlighting the importance of electricity sources.