A novel process towards the industrial realization of large-scale oxymethylene dimethyl ether production – COMET

Abstract

Oxymethylene dimethyl ethers (OME) show promising solubility and combustion properties for applications in various chemical processes and sectors. OME enable clean and quasi soot-free combustion, which can consequently lead to considerable NO_x emissions reduction. Besides reducing local emissions, OME can significantly reduce the global CO₂ emissions by substituting fossil diesel fuel if their production is based on sustainable methanol. Various process concepts for the OME production were proposed and investigated, but most of them have significant bottlenecks, which prevent their demonstration and scale-up in the near future. Only the production based on OME₁ and trioxane can already be demonstrated and scaled up, which, however, is complex and energy-intensive, considering a sustainable production based on H₂ and CO₂. Therefore, the novel COMET (clean OME technology) process concept is introduced and experimentally demonstrated utilizing only state-of-the-art process units. The COMET process relies solely on methanol and formalin as feedstock and overcomes the challenging water management aspect in the OME value chain, using a reactive distillation column. The COMET process is evaluated at a scale of 100 kilotons per annum OME_3–5 product for the system boundary starting from H₂O electrolysis and CO₂ capture. Key performance indicators are defined and compared with alternative processes from the literature. The COMET process shows a high carbon efficiency of 88% and overall energy efficiency of 54% in comparison to the alternative OME_3–5 production processes introduced in the literature. Moreover, the COMET process offers the forthwith large-scale production of OME in a relatively simple process chain and high technology readiness level.