Method for removing heavy and light impurities in maleic anhydride system

Abstract

The invention discloses a method for removing light impurities such as water, acetic acid and propylene and heavy impurities which can be condensed into tar in the maleic anhydride production field. According to two conventional technologies, a gas stripping column is arranged on the bottom of an absorption column so as to fill air for gas stripping, two switching coolers are arranged in front of the absorption column so as to respectively remove light and heavy impurities, and heavy impurities are condensed in the switching coolers in a practical operation process, so that cleaning is frequent and difficult; and the light impurities are subjected to gas stripping in the absorption column, so that the energy consumption is high, and the impurities cannot be thoroughly removed. According to the method, the gas stripping column is separately arranged, a column bottom is design to be conical, the light impurities are removed on the upper column part through air stripping, and the heavy impurities are removed on the column bottom through standing, so that the impurity content is effectively lowered, the product quality is improved, and an equipment blockage problem is solved; and moreover, the method is simple to operate and suitable for newly constructing and technologically reconstructing a solvent absorption maleic anhydride device, so that the economic benefit of the maleic anhydride production is greatly improved.

Description

technical field [0001] The invention relates to a maleic anhydride production technology, in particular to a method for removing light and heavy impurities in a maleic anhydride system. Background technique [0002] Maleic anhydride, referred to as maleic anhydride, as one of the three major organic anhydrides, is a commonly used important organic chemical raw material. It is widely used in unsaturated polyester resin, paint, paint, ink, engineering plastics, medicine, pesticide, food, feed, oil additive, papermaking, textile and other fields, and has a very broad development prospect. [0003] The production method of maleic anhydride is: the raw material benzene or n-butane is oxidized with air, the reaction process is carried out under the action of a certain catalyst, and the reaction gas containing maleic anhydride is obtained, which is cooled, absorbed, desorbed, refined and recovered. Process to obtain the product maleic anhydride. [0004] Among them, according to ...

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Problems solved by technology

[0011] 2. In order to meet the requirements of the solvent to absorb maleic anhydride gas in the absorption tower itself, it is necessary to control the outlet gas at a lower temperature at the top of the tower, and the stripping process is to introduce high-temperature stripping air at the bottom of the absorption tower, so more The circulating solvent takes away this part of the heat from the tower, correspondingly consuming more circulating cooling water and electric energy

Based on the above points, there will still be a certain amount of water, acetic acid, acrylic acid and other impurities in the rich solvent extracted from the bottom of the tower. After the system has been running for a period of time, equipment and pipelines will still be blocked in the subsequent desorption and refining sections.

Due to the above disadvantages, using two methods to remove light and heavy impurities is always unsatisfactory

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