Techno-economic assessment and carbon footprint of processes for the large-scale production of oxymethylene dimethyl ethers from carbon dioxide and hydrogen

Poly(oxymethylene)dimethyl ethers (OME) show promising fuel properties, enabling their use in existing infrastructure, especially as alternatives or additives to diesel fuel, leading to a significant reduction in local emissions (e.g., soot and NOx). Additionally, OME can be produced from methanol, enabling their production based on a renewable feedstock, which can significantly reduce the carbon footprint in comparison to fossil fuels. However, an industrial process to sustainably produce OME on a large-scale has not been developed to date. Based on the results of detailed simulations in Aspen Plus®, this work compares the most promising process routes for the production of OME3-5 in a system boundary including H2via water electrolysis and captured CO2 from point sources or ultimately using direct air capture technologies. One of the main outcomes of this work is the standardized methodology introduced for the techno-economic and CO2 footprint evaluation and comparison of the diverse processes. The comparison criteria are based on systematic approaches covering process materials and energy efficiency, technology readiness level, costs, and the carbon footprint. The process routes based on anhydrous formaldehyde and methanol or methylal feedstock show higher energy efficiencies and lower carbon footprints than other routes considering the commercial aqueous formaldehyde. However, the synthesis of anhydrous formaldehyde is under research and development and not yet industrially established. Importantly, considering the net production costs of OME3-5 from the four simulated process routes, there is no significant difference, which is attributed to the rather high share of the operational cost, and specifically the cost of the H2 and CO2 feedstock. Using sensitivity analysis, the influence of feedstock costs and carbon footprint on the evaluation criteria is identified, elaborating the potential of feasible and sustainable OME production under favourable conditions.