Method and device for separating polymer generated in slurry polyethylene production process

Abstract

The invention relates to a method and device for separating a polymer generated in a slurry polyethylene production process. The method comprises the steps: carrying out a polymerization reaction by using a slurry (slurry-gas phase method) process to generate a polymerization solid-liquid mixture; introducing the polymerization solid-liquid mixture into a pressure filter to obtain filtrate and a filter cake, and removing a liquid in the filter cake in the filter; collecting the filtrate, a liquid-removed gas and a cleaning effluent into an adsorbent collecting tank; and delivering the filtrate, the liquid-removed gas and the cleaning effluent into a reaction system together with a complemented fresh adsorbent so a to be used as an adsorbent. The device mainly comprises a drum-type liquid phase reactor, the pressure filter, a condenser and a diluent collecting tank. By using the method and device, the technical process and the system structure are simplified, the construction investmentis reduced, and the energy consumption in production is reduced.

Description

technical field [0001] The invention relates to a polymer separation method and a separation device in a slurry method polyethylene production process, belonging to the technical field of chemical industry. Background technique [0002] Polyethylene is a thermoplastic resin obtained by polymerization of ethylene. It also contains copolymers of ethylene and a small amount of α-olefin in industry. Polyethylene is odorless, non-toxic, and feels like wax. It has excellent low temperature resistance and chemical stability. Good resistance to most acid and alkali corrosion, insoluble in common solvents at room temperature, low water absorption, excellent electrical insulation. Polyethylene has a wide range of uses, mainly used to make films, packaging materials, containers, pipes, monofilaments, wires and cables, and daily necessities, and can also be used as high-frequency insulation materials for TVs and radars. [0003] At present, the production process of polyethylene can be...

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Problems solved by technology

[0006] 1) The hydrocarbon solvent used as a diluent does not participate in the reaction during the process, but a large amount of steam tracing and cooling water condensation are required in the process of gasification, flash evaporation, compression, and condensation, resulting in huge consumption of public works;

[0007] 2) Part of the unreacted ethylene also consumes a certain amount of steam heating and cooling water cooling in the above-mentioned cycle of gasification, flash evaporation, compression, and condensation, resulting in increased consumption of public works;

[0008] 3) The separation of polyethylene powder from the gasified diluent and ethylene requires multiple filters and separators, which not only results in high equipment investment costs, but also has a long process flow, which increases the unreliability of the device operation;

[0009] 4) The compression of a large amount of diluent gas requires a large compressor capacity, which not only results in high equipment investment costs, but also consumes a large amount of electric energy during operation

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