A pervaporation blend membrane for separating methanol-tetrahydrofuran and its preparation method

Abstract

The invention relates to a pervaporation blend membrane for separating a mixture methanol and tetrahydrofuran and a preparation method of permeation vaporization blend membrane. The pervaporation membrane with a uniform and compact structure is prepared by virtue of a blending method by adopting P84 polyimide and cellulose acetate as basic raw materials. The pervaporation blend membrane has the beneficial effects that the blend membrane gives priority to the permeation of methanol and can separate the methanol and tetrahydrofuran mixture and purify the tetrahydrofuran; the pervaporation method adopted to separate the methanol-tetrahydrofuran mixture has the advantages of high separation efficiency, simple equipment, low energy consumption, no pollution and the like; and the blend membrane is excellent in separation performance and high in chemical stability, the materials for preparing the membrane is conventional, easy to get and low in price, and the industrialized production is facilitated.

Description

technical field [0001] The invention belongs to the field of pervaporation membrane preparation and application thereof, and relates to a pervaporation blend membrane for separating methanol-tetrahydrofuran and a preparation method thereof. Background technique [0002] Tetrahydrofuran is an important raw material for organic synthesis and an excellent solvent with a wide range of uses. In industrial production, tetrahydrofuran has good solubility to many organic and inorganic substances, especially suitable for dissolving polyvinyl chloride, polyvinylidene chloride and butadiene aniline; it is also used as natural resin, synthetic resin, polyurethane and polyether rubber, etc. solvents and solvents for adhesives for plastic pipes. However, when tetrahydrofuran is used as a solvent, impurities are often brought in. If it is discarded without purification, it will cause economic losses and pollute the environment, which does not meet the requirements of energy-saving develop...

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Problems solved by technology

[0004] The patent (CN202336224) relates to a device and method for separating methanol-tetrahydrofuran by double-tower pressure swing rectification. The mixture is first separated through an atmospheric tower, and then separated through a high-pressure tower to obtain tetrahydrofuran with high purity. The process of this method is complicated, and the separation The efficiency is low, and the high-pressure tower equipment not only has a large investment cost, but also has high energy consumption during operation

[0005] Genduso in Belgium used azeotropic distillation to separate methanol and tetrahydrofuran mixtures. By introducing n-hexane to destroy the vapor-liquid equilibrium of methanol and tetrahydrofuran in the rectification column, tetrahydrofuran and cyclohexane-methanol mixtures were obtained. This method requires the introduction of an entrainer , and the types of entrainer are less and the price is higher, so the total investment cost is huge [Genduso, G.etal AIChE Journal.2014,60(7):2584-2595]

[0006] Shin et al. of South Korea used ethylene glycol as the extractant to separate the methanol / THF mixture by rectification. This method introduced the third component, the process was complicated, and there was a large amount of circulating heating of the extractant, which not only increased the investment cost, but also Increase process energy consumption [Shin, Y, S. et al Journal of Chemical Engineering of Japan. 2017, 50(4): 225-230]; patent (CN202336224) involves a kind of extractive distillation to separate tetrahydrofuran-ethanol azeotrope The device and method, ethylene glycol is the extractant, and the purity of its tetrahydrofuran product is only 90%

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