Production of Oxymethylene Dimethyl Ethers from Hydrogen and Carbon Dioxide-Part II: Modeling and Analysis for OME3-5

Oxymethylene dimethyl ethers (OMEn) have high potential as diesel fuels or blending components due to their promising combustion properties and can be produced from hydrogen (H-2) and carbon dioxide (CO2) by combining existing process concepts. However, such a process chain has not been analyzed in detail yet, so its performance and bottlenecks are unknown. In this second part of our two-part article, we analyze a process chain for production of the longer chain variant OME3-5 from renewable H-2 and green CO2 via trioxane and OME1. We simulate in Aspen Plus using detailed thermodynamic models with coupled oligomerization reactions and rigorous unit operation models. The overall exergy efficiency of OME3-5 production from H-2 and CO2 using established process concepts is 53%. Therein, the trioxane process step has the highest losses due to its high heat demand. Considering a pinch-based heat integration throughout the entire process chain its total heat demand can be reduced by 16%. Thus, the exergy efficiency increases to 54%. This is still significantly lower compared to the production of other alternative fuels like OME1 methane, and dimethyl ether. Thus, more efficient processes, e.g., by avoiding trioxane production, are required.