Investigating the Effects of Water in Feedstock on the Energetic Efficiency of Producing Polyoxymethylene Dimethyl Ethers

Large-scale eco-efficient production of polyoxymethylene dimethyl ethers (PODEn) has garnered wide attention as environmental-friendly diesel additives. Among the various PODEn research studies, the effect of water on the PODEn process is one of the most important research fields. In this work, the effects of water content in feedstock on the reboiler duty of the PODEn process were analyzed by rigorous simulation. To ensure the accuracy of the model, vapor–liquid equilibria (VLE) data of PODE2-H2O were measured and the model was regressed by using the experimental data. Furthermore, the production process consisting of raw material preparation section and PODEn synthesis section was evaluated by comparing it with the various water contents (0, 0.05, 0.10 and 0.15 g/g) in feedstock. We found the reboiler duty in the case of 0.10 g/g water in feedstock was lowest (77.99 MJ/kg), which is even lower than anhydrous case (100.24 MJ/kg). The results suggest that the water can be appropriately allowed in the production, which can reduce the reboiler duty of the PODEn.