Describing oxymethylene ether synthesis based on the application of non-stoichiomsetric Gibbs minimisation

Abstract

The synthesis of short chain poly oxymethylene dimethyl ethers, also known as oxymethylene ethers (OME; molecular formula: H₃CO–(CH₂O)_n–CH₃ where n = 1–8) is described through the application of non-stoichiometric Gibbs minimisation (NSGM) to a synthesis based on methanol and anhydrous formaldehyde. The presented approach shows several synthesis efficiency and economic advantages as demonstrated through a simulation platform based on MATLAB® (where the two main reactors models are implemented) and the NSGM, which utilises stochastic global optimisation (SGO) to perform an unconstrained minimisation and convergence of the complex OME reaction system (comprising >31 reactants and also recycling of non-reacted components). A complimentary experimental validation is provided for the OME reaction equilibrium model based on the use of different feeds, namely 1) CH₃OH/CH₂O and 2) H₃C–O–(CH₂O)₁–CH₃/(CH₂O)₃. The presented results demonstrate the robustness of the applied NSGM for this multi-reaction system. With regard to the overall evaluation of the presented process, key performance indicators (KPIs) are discussed based on the material balance results of the simulation platform. A cost model for the OME synthesis process based on different feeds is also presented based on an annual production of one million metric tonnes of OME_3–5. The cost of 571 € per tonne demonstrates the economic potential of the presented OME production process.