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Method for producing terephthalate through continuous esterification

A technology of terephthalate esterification and esterification, which is applied in the chemical industry, can solve problems such as increased investment and energy consumption, product refining burden, etc., and achieve the effects of reducing circulation, improving raw material utilization, and reducing costs

Pending Publication Date: 2022-05-20
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Using other high-boiling point solvents to prepare PTA slurry, although the preheating problem of PTA slurry under lower pressure can be realized, but the high-boiling point solvent itself is an impurity in the reaction system, so a large amount of impurities will not only bring g

Method used

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  • Method for producing terephthalate through continuous esterification
  • Method for producing terephthalate through continuous esterification
  • Method for producing terephthalate through continuous esterification

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Add the PTA powder with a particle size of 90-140μm and the liquid esterification product circulated from the esterification tower to the slurry mixing tank at a feeding rate of 16.6kg / h and 66.4kg / h respectively. It is sent to the heat exchanger of the esterification tower, and after heat exchange to 270°C, it enters the esterification tower from the middle and upper part of the esterification tower; at 270°C, 3.0MPa superheated methanol vapor enters the esterification tower from the lower part of the esterification tower at a flow rate of 19.2kg / h In the esterification tower, the liquid material in the esterification tower is in countercurrent contact with superheated methanol steam to carry out the esterification reaction. The operating temperature of the esterification tower is 270 ° C, the pressure (gauge pressure) at the top of the tower is 2.6 MPa, and the liquid hourly space velocity (volume flow rate of slurry liquid Divided by the volume of the esterification t...

Embodiment 2

[0048] Add the PTA powder with a particle size of 250-475 μm and the liquid esterification product circulated from the esterification tower to the slurry mixing tank at a feeding rate of 16.6kg / h and 66.4kg / h respectively. It is sent to the heat exchanger of the esterification tower, and after heat exchange to 270°C, it enters the esterification tower from the middle and upper part of the esterification tower; at 270°C, 3.0MPa superheated methanol vapor enters the esterification tower from the lower part of the esterification tower at a flow rate of 19.2kg / h In the esterification tower, the liquid material in the esterification tower is in countercurrent contact with superheated methanol steam for esterification reaction. The operating temperature of the esterification tower is 270°C, the top pressure (gauge pressure) is 2.6MPa, and the liquid hourly space velocity is 0.25h -1 , the excess methanol vapor and the water produced by the esterification reaction leave the esterifica...

Embodiment 3

[0050] Add the PTA powder with a particle size of 38-75μm and the liquid esterification product circulated by the esterification tower to the slurry mixing tank at a feeding rate of 16.6kg / h and 66.4kg / h respectively. It is sent to the heat exchanger of the esterification tower, and after heat exchange to 270°C, it enters the esterification tower from the middle and upper part of the esterification tower; at 270°C, 3.0MPa superheated methanol vapor enters the esterification tower from the lower part of the esterification tower at a flow rate of 19.2kg / h In the esterification tower, the liquid material in the esterification tower is in countercurrent contact with superheated methanol steam for esterification reaction. The operating temperature of the esterification tower is 270°C, the top pressure (gauge pressure) is 2.6MPa, and the liquid hourly space velocity is 0.25h -1 , the excess methanol vapor and the water produced by the esterification reaction leave the esterification ...

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Abstract

The invention discloses a method for producing terephthalate by continuous esterification of purified terephthalic acid, which comprises the following steps: preparing slurry from solid powdery purified terephthalic acid and a part of esterification product circularly returned from an esterification tower or a flash tank, and reacting with superheated alkyl alcohol steam in the esterification tower, a catalyst can be used or not used in the esterification process, part of the generated material is recycled back to the slurry preparation kettle, and part of the generated material is sent to the downstream as a product. According to the method, the purified terephthalic acid solid material can be continuously and stably conveyed, and while the esterification rate is guaranteed, the process is simplified, the equipment investment is reduced, the total alcohol-acid ratio in the esterification process is reduced, and the material consumption and the energy consumption are reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a method for continuously esterifying terephthalic acid to produce terephthalic acid esters. Background technique [0002] Terephthalates, especially dimethyl terephthalate (DMT), used to be the main raw material for the production of polyesters such as ethylene terephthalate (PET). At the end of the 1940s, the Witten company of Germany and the Hercules company of the United States successively invented the air-stage oxidative esterification of p-xylene to synthesize DMT. Combined oxidative esterification method, also known as Witten method or Hercules method. [0003] The use of DMT to produce polyester was due to the fact that the p-xylene production technology at that time was difficult to produce high-purity terephthalic acid that met the requirements of polymer production, that is, purified terephthalic acid (PTA, alias: terephthalic acid, Pine oil phthalic acid;...

Claims

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Application Information

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IPC IPC(8): C07C67/08C07C69/82
CPCC07C67/08C07C69/82Y02P20/10
Inventor 丁云杰李经伟陈维苗于婷婷宁丽丽宋宪根
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI