Hybrid process of distillation side-connected with pervaporation for separation of methanol/MTBE/C4 mixture Original Research Article

A special hybrid process of distillation and pervaporation was designed and simulated. The pervaporation membrane was prepared to permeate methanol preferentially from the mixture of C4, methanol and fewer methyl tert-butyl ether (MTBE). Pervaporation unit that side-connected with distillation was used to remove off methanol and to make the distillation gotten over azeotropic point. For the case this paper discussed, the qualified product of C4 and MTBE with methanol mole fraction less than 1×10−4 can be obtained only by this hybrid separating process, and the pervaporation permeate stream with methanol concentration greater than 0.92 could be recycled to reactor. The matching of handling capacity of pervaporation with distillation and the reflux ratio of distillation tower were the two important factors to achieve satisfactory separation. The hybrid process could treat the methanol concentration fluctuation in feed under the condition of sufficient pervaporation membrane area were designed in advance.