System for continuously purifying reaction product of esterification

Patent metadata

Field	Value
Publication number	US-11021432-B2
Application number	US-202016838816-A
Country	US
Kind code	B2
Filing date	Apr 2, 2020
Priority date	Apr 4, 2019
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

The present disclosure relates to a system and a method for continuously purifying a reaction product of esterification, where the system includes a neutralizer, a distiller, and a product purifier. Through the present system and the method, it is possible to perform a continuous purification process efficiently, and to reduce lower alcohol wastewater generated during purification.

First claim

The invention claimed is:

1. A system for continuously purifying a reaction product of esterification, the system comprising:
a neutralizer including an inlet into which an unpurified product mixture containing a mixture of two kinds of alcohols having different esters and different numbers of carbon atoms is injected, a neutralization agent injection port through which a basic aqueous solution is injected as a neutralization agent, an inner space in which neutralization and water separation are performed, a first discharge port from which an organic layer fraction is discharged, and a second discharge port from which a water layer fraction is discharged;
a distiller including an organic layer fraction injection port connected to the first discharge port of the neutralizer, a separation space in which the separation of the alcohol mixture is performed, an alcohol-rich stream discharge port provided on an upper portion of the separation space, and an ester-rich stream discharge port provided on a lower portion of the separation space; and
a product purifier including a purifier inlet connected to the ester-rich stream discharge port of the distiller, a purification space in which gas-liquid separation is performed, an alcohol discharge port provided on an upper portion of the purification space and from which an alcohol fraction is discharged, and a product discharge port provided on a lower portion of the purification space and from which an ester fraction is discharged,
wherein the inner space of the neutralizer is provided with one or more partition walls such that the inner space is divided into a neutralization space and a layer separation space in the left and right directions respectively and a passage connecting the two spaces is formed, and the passage starts from an upper portion of the neutralization space.

2. The system of claim 1 , wherein the neutralizer further comprises a neutralization agent injection port through which a basic aqueous solution is injected into the neutralization space and a waste liquid treatment port from which a waste liquid is discharged from the layer separation space.

3. The system of claim 1 , further comprising
a mixed alcohol separation column including a mixed alcohol supply unit in which the alcohol-rich stream discharge port of the distiller and the alcohol discharge port of the product purifier are connected, an upper removal unit from which water is discharged, a middle discharge unit from which lower alcohol is discharged, and a lower discharge unit from which higher alcohol is discharged; and
a wastewater treatment tank including a lower alcohol wastewater line connected to the second discharge port of the neutralizer, a higher alcohol supply line connected to the lower discharge unit of the mixed alcohol separation column, a wastewater treatment space in which mixing and layer separation are performed, an alcohol mixture discharge line from which higher alcohol and lower alcohol are discharged, and a process wastewater treatment line, wherein the wastewater treatment space of the wastewater treatment tank is provided with one or more partition walls such that the wastewater treatment space is divided into a mixing space and a layer separation space in the left and right directions respectively and a passage connecting the two spaces is formed, and the passage starts from an upper portion of the mixing space.

4. A method for continuously purifying a reaction product of esterification, the method comprising:
a step S 1 of performing layer separation on an unpurified product mixture including an alcohol mixture, as an unreacted material, containing two kinds of alcohols having different numbers of carbon atoms selected from 3 to 10 and including ester which is a product of an esterification reaction into an organic layer fraction which is rich in ester and a water layer fraction including lower alcohol in the presence of a basic aqueous solution in a neutralizer having a partition wall structure;
a step S 2 of injecting the organic layer fraction into a distiller to remove an alcohol-rich stream from an upper portion of the distiller and to discharge an ester-rich stream from a lower portion thereof; and
a step S 3 of injecting the ester-rich stream into a product purifier to separate an ester fraction from a lower portion of the product purifier and to separate an alcohol fraction from an upper portion thereof.

5. The method of claim 4 , wherein the water layer fraction comprises water and lower alcohol, and the lower alcohol of the water layer fraction is included in an amount of 0.5-3.0 parts by weight based on 100 parts by weight of the mixed weight of the water and the lower alcohol.

6. The method of claim 4 , wherein both a neutralization of a catalyst and a neutralization of the unpurified product mixture are performed in the neutralizer.

7. The method of claim 4 , wherein mutual heat exchange is performed between an exit stream of the neutralizer through which the organic layer fraction flows and an entrance stream of the neutralizer through which the unpurified product mixture flows.

8. The method of claim 4 , wherein the basic aqueous solution injected into the neutralizer has a base concentration of 0.1-50 wt %.

9. The method of claim 4 , wherein in the product purifier of the step S 3 , separation by distillation using steam is performed.

10. The method of claim 4 , further comprising a step of filtering using a filer, wherein the step of filtering is either performed on an unpurified product mixture before the step S 1 , or performed on the ester fraction which is a product separated through a lower portion of the product purifier after the step S 3 .

11. The method of claim 4 , wherein the water layer fraction is injected into a wastewater treatment tank and through the injection of higher alcohol, subjected to layer separation into an alcohol layer including the higher alcohol and the lower alcohol, and a wastewater layer.

12. The method of claim 11 , wherein the alcohol-rich stream separated from the upper portion of the distiller and the alcohol fraction separated from the upper portion of the product purifier, and the alcohol layer of the wastewater treatment tank are injected into a mixed alcohol separation column to separate higher alcohol and lower alcohol.

13. The method of claim 11 , wherein the wastewater layer contains the lower alcohol in an amount of 3.0 wt % or less based on the total weight of the wastewater layer.

14. The method of claim 4 , wherein the ester is one or more selected from the group consisting of terephthalate, isophthalate, phthalate, cyclohexane 1,2-diester, cyclohexane 1,3-diester, cyclohexane 1,4-diester, citrate, trimellitate, cyclohexane tricarboxylate-based compound, benzene tetracarboxylate-based compound, furan tetracarboxylate-based compound, cyclohexane tetracarboxylate-based compound and tetrahydrofuran tetracarboxylate-based compound.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Hyun Kyu
• Lee Sung Kyu
• Jun Hyoung
• Jin Chan Hyu
• Moon Jeong Ju
• Kim Joo Ho

Classifications

• C07C67/54 Primary

  by distillation · CPC title

• B01J19/00

  Chemical, physical or physico-chemical processes in general; Their relevant apparatus · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• B01J8/04

  the fluid passing successively through two or more beds · CPC title

• B01D3/38 Primary

  Steam distillation · CPC title