Hexane recovery heat exchange method

Abstract

The invention relates to a heat exchange method for recycling hexane, mainly solving the problems of high consumption of low-pressure steam and circulating cooling water, unreasonable energy utilization, high equipment construction investment and low plate efficiency in the prior art. The heat exchange method for recycling hexane comprises the following steps that a) water containing undercooling liquid phase hexane material flow 3 enters a hexane liquid phase heat exchanger 1, and after heat exchange, a material flow 4 is obtained, wherein the temperature of the undercooling liquid phase hexane material flow 3 is 30-50 DEG C and the temperature of the material flow 4 is 65-85 DEG C; b) the material flow 4 enters the upper part of a hexane dehydrating tower 2, and after the material flow is separated, a material flow 5 is obtained at the top of the tower and a material flow 6 is obtained at the bottom of the tower; and c) the material flow 6 enters a hexane liquid phase heat exchanger 1 and exchanges heat with the material flow 3 so as to obtain a material flow 7, and the material flow 7 enters in the following processes, wherein the temperature of the material flow 6 is 85-105 DEG C, and the temperature of the material flow 7 is 50-70 DEG C. The problems in the prior art are well solved by the technical scheme, and the heat exchange method can be used for recycling hexane in the industrial production of high-density polyethylene.

Description

technical field

[0001] The invention relates to a hexane recovery heat exchange method. Background technique

[0002] High-density polyethylene (HDPE) is a highly crystalline, non-polar thermoplastic resin with a wide range of uses. Document CN200910090649.6 discloses a method for preparing ultrafine polyethylene powder, and document CN200910156643.4 discloses a double series reactor process for preparing polyethylene. In the production of high-density polyethylene in the prior art, in the hexane recovery unit, the feed to the hexane dehydration tower is a supercooled liquid phase, and the reboiler of the tower needs to be heated with low-pressure steam, resulting in an increase in the heat load of the hexane dehydration tower. However, the hot liquid phase discharge of the hexane dehydration tower needs to be cooled by circulating cooling water, and then sent to the storage tank for storage. Therefore, there are problems such as large consumption of low-pressure steam and...

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