Multi-step crystallization process of succinic acid hydrogenation for degradable plastics

Abstract

The invention discloses a multi-step crystallization production process of succinic acid hydrogenation for degradable plastics, including (1) adding maleic anhydride and water into a stirring maleic anhydride hydrolysis tank and mixing evenly to complete the hydrolysis reaction to obtain maleic acid aqueous solution; (2) add maleic acid aqueous solution to the maleic acid hydrogenation reactor after being preheated by a preheater, and simultaneously feed high-pressure hydrogen to react to obtain a succinic acid solution; (3) succinic acid The solution is sequentially passed into several crystallizers for gradual cooling and crystallization; (4) The crystallized material is subjected to solid-liquid separation, and the separated liquid is recycled to the mother liquor tank for recycling, and the separated solid is dried and stored in the finished product silo Package. The present invention does not need to use an independent gas-liquid separation device, the substances in the mother liquor and the cold source are recovered and utilized, and the excess hydrogen is directly recovered from the flash heat of the crystallizer, and then the recovered hydrogen is passed into the maleic acid hydrogenation reactor for reuse. Among them, hydrogen, waste heat, and mother liquor can be reused, and the overall zero emission is achieved.

Description

technical field [0001] The invention relates to the field of succinic acid production technology, in particular to a multi-step crystallization production technology of succinic acid hydrogenation for degradable plastics. Background technique [0002] While traditional chemical plastics bring convenience to people, they also bring unimaginable troubles. Many plastics will not degrade under natural conditions, and will release harmful gases during the combustion process, causing huge damage to the ecological environment. Pollution. [0003] In recent years, with the development of the application of degradable materials, the market demand for succinic acid (succinic acid) has grown rapidly. Succinic acid is one of the important monomers for the production of biodegradable polyesters PBS and PBA. Biodegradation of PBS chains begins with hydrolysis of ester bonds, resulting in the formation of water-soluble fragments with molar masses below 500. These short PBS segments can ...

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Problems solved by technology

In the 1930s, the electrochemical reduction method has achieved industrial production and is the main technology for the production of succinic acid in my country. However, in actual production, there are problems such as large power consumption, serious electrode corrosion, and large sewage discharge, which are not conducive to large-scale production. And other issues

[0005] Chinese patent CN103570650A has recorded a kind of technological process of hydrogenation of maleic anhydride to continuously produce succinic anhydride and co-production of succinic acid. Water reaction obtains product succinic acid, and the yield of succinic acid is relatively low; Chinese patent CN111689845A describes a process for preparing succinic acid by hydrogenation in water phase, which includes a stirring tank, a raw material tank, a raw material and hydrogen premixing unit, Composed of raw material feed pipe, hydrogenation reactor, gas-liquid separation tank and crystallization tank; this process also requires the use of gas-liquid separation tank, and adopts one-step crystallization, which makes the cooling operation difficult and the crystallization rate is low

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