Search

CN-122006597-A - System for improving yield of polyester-grade glycol

CN122006597ACN 122006597 ACN122006597 ACN 122006597ACN-122006597-A

Abstract

The invention discloses a system for improving the yield of polyester-grade ethylene glycol, which comprises an ethylene glycol refining tower, a butanediol removing tower positioned at the upstream of the process of the ethylene glycol refining tower, and an aldehyde and ester removing tank positioned at the downstream of the process of the ethylene glycol refining tower, wherein the product of the ethylene glycol refining tower reacts with a catalyst in the aldehyde and ester removing tank to obtain a high-grade ethylene glycol product, the downstream end of the process of the ethylene glycol refining tower is provided with a liquid-phase hydrogenation reactor, and the liquid-phase hydrogenation reactor is used for receiving the product of the ethylene glycol refining tower and carrying out hydrogenation reaction on part of the product to convert trace impurities in the product into light components. The system of the invention can improve the product quality stability, prolong the service life of the key catalyst and improve the yield of the target product by increasing the hydrogenation reaction of the product by the liquid-phase hydrogenation reactor.

Inventors

  • HAN JIE

Assignees

  • 内蒙古卓正煤化工有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. A system for increasing the production of polyester grade ethylene glycol, the system comprising: A glycol refining tower (1); a butanediol removal column (2) located upstream of the process of the ethylene glycol refining column (1), and An aldehyde and ester removing tank (4) positioned at the downstream of the process of the ethylene glycol refining tower (2), wherein the product of the ethylene glycol refining tower (1) reacts with a catalyst in the aldehyde and ester removing tank (4) to obtain a high-polyester-grade ethylene glycol product; The downstream end of the process of the ethylene glycol refining tower (1) is provided with a liquid-phase hydrogenation reactor (3), and the product of the ethylene glycol refining tower (1) is received through the liquid-phase hydrogenation reactor (3) and subjected to hydrogenation reaction to convert trace impurities in the product into light components.
  2. 2. The system for improving the yield of the polyester-grade ethylene glycol according to claim 1, wherein an air cooler (103) and an ethylene glycol refining column reflux tank (104) are sequentially connected to the upper part of the ethylene glycol refining column (1) through a first pipeline (101) according to a process flow, and the ethylene glycol refining column reflux tank (104) is communicated with the liquid-phase hydrogenation reactor (3) through a first reflux pipeline (105) so as to convey the product of the ethylene glycol refining column (1) to the liquid-phase hydrogenation reactor (3); The lower part of the glycol refining tower (1) is communicated with the aldehyde and ester removing tank (4) through a second pipeline (102).
  3. 3. The system for improving the yield of the polyester-grade ethylene glycol according to claim 2, wherein the upper end of the liquid-phase hydrogenation reactor (3) is connected with a hydrogenation unit (301) at the upstream of the process through a hydrogenation pipeline so as to input hydrogen into the liquid-phase hydrogenation reactor (3), and the part of hydrogen is decompressed and heated to be gathered with a product output by the ethylene glycol refining tower (1) at the top of the liquid-phase hydrogenation reactor (3).
  4. 4. A system for increasing the yield of polyester-grade ethylene glycol according to claim 2 or 3, characterized in that the product hydrotreated by the liquid-phase hydrogenation reactor (3) is refluxed to the polybutylene-removal column (2) upstream of the process through the liquid-phase hydrogenation reactor reflux line (302).
  5. 5. The system for improving the yield of the polyester-grade ethylene glycol according to claim 4, wherein the upper part of the butanediol removing tower (2) is sequentially connected with a waste pot (202) and a butanediol removing tower reflux tank (203) through a third pipeline (201) according to a process flow, and the butanediol removing tower reflux tank (203) is used for refluxing a part of products subjected to the light component removal of the butanediol removing tower (2) to the ethylene glycol refining tower (1) through a butanediol removing tower reflux tank first reflux pipeline (204).
  6. 6. The system for improving the yield of the polyester-grade ethylene glycol according to claim 5, wherein the polybutylene-removing tower reflux tank (203) is used for refluxing part of the product to the polybutylene-removing tower (2) through a second reflux pipeline (204) of the polybutylene-removing tower and carrying out light component removal treatment again.
  7. 7. The system for improving the yield of the polyester-grade glycol according to claim 4, wherein the product in the liquid-phase hydrogenation reactor (3) is subjected to hydrogenation reaction of a reaction bed and then is subjected to separation treatment of a gas-liquid two-phase product after the reaction by a gas-liquid separation section at the bottom of the reactor; the liquid phase product is refluxed to the butanediol removing tower (2) through a reflux pipeline (302) of the liquid phase hydrogenation reactor.
  8. 8. The system for increasing the production of polyester-grade ethylene glycol of claim 7, wherein the gas phase product is divided into three branches: The first branch is a gas-liquid separation section for conveying the gas phase product to a hydrogen condenser (305) for cooling and then refluxing to the bottom of the liquid phase hydrogenation reactor (3); the second branch is to convey the gas phase product to a hydrogen recovery system for recycling; and the third branch is to directly convey the gas-phase product to the torch for incineration treatment.
  9. 9. A system for increasing the yield of polyester-grade ethylene glycol according to claim 3, characterized in that the hydrogenation unit (301) upstream of the process adopts an oxalate hydrogenation unit of the original system, and a hydrogen pipeline with a size DN25 is led out from the oxalate hydrogenation unit and is connected to the upper end of the liquid-phase hydrogenation reactor (3).
  10. 10. The system for improving the yield of the polyester-grade ethylene glycol according to claim 5, wherein the bottom of the butanediol removing tower (2) is connected with the ethylene glycol refining tower (1) through a butanediol removing tower reflux pipe (205).

Description

System for improving yield of polyester-grade glycol Technical Field The invention relates to the technical field of ethylene glycol production technology, in particular to a system for improving the yield of polyester-grade ethylene glycol. Background In the oxalate hydrogenation process, along with the extension of the operation time of a Cu/SiO 2 catalyst, after the catalyst enters the end stage of the catalyst, the activity of the catalyst is gradually attenuated, the reaction selectivity is reduced, the generation amount of impurities in a reaction system is continuously increased, the content of ethylene glycol which is a target product is synchronously reduced, and at the moment, trace impurities are enriched in crude first-hot spring produced after the reaction, and the crude first-hot spring mainly comprises ketones, aldehydes, organic compounds containing unsaturated bonds and the like. Meanwhile, the impurities can be subjected to irreversible adsorption or chemical reaction with the dealdehyding and degreasing catalyst, so that the service life of the catalyst is obviously shortened, and in addition, a large amount of glycol and the organic impurities can be entrained in the products of a butanediol removal tower reflux system, a glycol refining tower reflux tank and a glycol recovery unit, so that the effective recovery rate of target products is reduced, and the final yield of the polyester-grade glycol is greatly reduced. Accordingly, based on the above-mentioned technical problems, there is a need for developing a system for improving the yield of polyester-grade ethylene glycol. Disclosure of Invention The invention aims to provide a system for improving the yield of polyester-grade glycol, which can improve the quality stability of products, prolong the service life of key catalysts and improve the yield of target products. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a system for improving the yield of polyester-grade glycol, which comprises: A glycol refining tower; A butanediol removal column located upstream of the ethylene glycol refining column process, and The formaldehyde-removing and ester-removing tank is positioned at the downstream of the glycol refining tower process, and the product of the glycol refining tower reacts with the catalyst in the formaldehyde-removing and ester-removing tank to obtain a high-polyester-grade glycol product; the downstream end of the process of the ethylene glycol refining tower is provided with a liquid-phase hydrogenation reactor, and the liquid-phase hydrogenation reactor is used for receiving the product of the ethylene glycol refining tower and carrying out hydrogenation reaction on the product to convert trace impurities in the product into light components. Further, the upper part of the ethylene glycol refining tower is sequentially connected with an air cooler and an ethylene glycol refining tower reflux tank through a first pipeline according to a process flow, and the ethylene glycol refining tower reflux tank is communicated with the liquid-phase hydrogenation reactor through a first reflux pipeline so as to convey the product of the ethylene glycol refining tower to the liquid-phase hydrogenation reactor; the lower part of the glycol refining tower is communicated with the aldehyde and ester removing tank through a second pipeline. Further, the upper end of the liquid-phase hydrogenation reactor is connected with a hydrogenation unit at the upstream of the process through a hydrogenation pipeline so as to input hydrogen into the liquid-phase hydrogenation reactor, and the part of hydrogen is decompressed and heated and then is collected with a product output by the ethylene glycol refining tower at the top of the liquid-phase hydrogenation reactor. Further, the product after being hydrotreated by the liquid-phase hydrogenation reactor is refluxed to the butanediol removal tower at the upstream of the process through a reflux pipeline of the liquid-phase hydrogenation reactor. Further, the upper part of the butanediol removing tower is sequentially connected with a waste pot and a butanediol removing tower reflux tank through a third pipeline according to the process flow, and the butanediol removing tower reflux tank is used for refluxing a part of products subjected to the light component removal of the butanediol removing tower to the ethylene glycol refining tower through a first reflux pipeline of the butanediol removing tower reflux tank. And further, the reflux tank of the butylene-removing tower returns part of the product to the butylene-removing tower through a second reflux pipeline of the reflux tank of the butylene-removing tower, and the light component is removed again. Further, the product in the liquid-phase hydrogenation reactor is subjected to hydrogenation reaction of a reaction bed, and then is subjected to separation treatment by a ga