Method and device for triple-effect separation of methylbenzene and polyethylene

Abstract

The invention relates to a method for the triple-effect separation of methylbenzene and polyethylene and a device used for the method. The method comprises the following step: separating a polyethylene-containing methylbenzene waste liquid sequentially through primary reduced-pressure distillation, primary normal-pressure distillation and primary positive-pressure distillation, wherein methylbenzene steam serves as a heat source which is used repeatedly. The device comprises a waste liquid preheater, a negative-pressure evaporator, a methylbenzene condenser, a decanter, a tail gas condenser, a normal-pressure evaporator, a positive-pressure evaporator, a positive-pressure methylbenzene intermediate tank, a methylbenzene residue storage tank and a residue evaporation tank. The device provided by the invention is an energy-saving and emission-reducing device. According to the method provided by the invention, based on the distillation range difference of one liquid under different pressures, the material is concentrated by using secondary steam, thereby greatly saving the production cost.

Description

Technical field [0001] The invention relates to a three-effect method for separating toluene and polyethylene, and a device used in the method. technical background [0002] The super-fiber synthetic leather manufacturing plant uses toluene as a solvent to dissolve and wash the polyethylene in the base fabric during the manufacturing process of the non-woven fabric. As an elution solvent, the production capacity of the production line is proportional to the amount of toluene within a certain range, and the recovery device of toluene and toluene used in the production line of the enterprise is operated simultaneously. [0003] The toluene waste liquid in the production process of superfiber synthetic leather comes from the extraction tank and the chase tank in the production line, and the polyethylene concentration in the waste liquid is about 2%. In the production process, the water seal is used as a sealing measure for the cloth. Therefore, there is some water in the waste liquid...

AI Technical Summary

Problems solved by technology

[0004] In the past, the microfiber toluene recovery process was a single-effect treatment technology in Japan. Its energy consumption was high, and because of the water content, the distillation process was prone to bumping, which affected the quality of recovered toluene.

With the expansion of the production scale of the enterprise, the consumption of toluene increases accordingly. Therefore, the recovery of toluene restricts the production capacity of microfiber synthetic leather, and the double-effect recovery process no longer meets the needs of production expansion.

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