The distillation process is used for purifying dimethyl ether(DME),when one-step synthesis of DME from syngas is adopted.Experimental flow of distillation for DME refining was built and the results were measured under operation conditions.A mathematical model was presented to research the distillation process on the basis of equilibrium stage theory.The cyclical nested-iteration method in sequential convergence was developed for solving the model equations,since the liquid phase was non-ideal and the components had a big difference in boiling point under normal conditions.The model yielded satisfactory results for laboratory data and the simulation results showed that for distillate DME product with concentration no less than 99%(mole),the following operating conditions were recommended.The distillation process is at operating pressure 1.0 MPa,and the feed mass flow rate of less than 8.65 mol·m-2·s-1 is desirable.The distillation mixture is fed into the middle of the packing section and the reflux ratio is rigorously controlled in a certain range according to the DME concentration in feed.It is necessary to keep CO2 concentration in feed as low as possible in order to improve DME purity and yield.
