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Air lift externally circulating bubble fower oxidation unit for producing terephthalic acid

A technology of terephthalic acid and oxidation device, which is applied in the fields of organic chemistry, carboxylate preparation, chemical instruments and methods, etc., can solve the problems of intensified combustion consumption of solvents, reduced volume utilization rate of reactors, poor mixing, etc. The effect of simplicity, low construction and operating costs

Inactive Publication Date: 2004-04-07
CHINA TEXTILE IND ENG INST +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the case of a large aspect ratio, the problem of poor mixing is prone to occur, and there are large temperature gradients and concentration gradients along the tower height in the reactor, which reduces the volume utilization of the reactor and increases the consumption of solvent combustion.

Method used

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  • Air lift externally circulating bubble fower oxidation unit for producing terephthalic acid
  • Air lift externally circulating bubble fower oxidation unit for producing terephthalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The low-temperature oxidation process is used to produce terephthalic acid. The annual production capacity of a single reactor is 200,000 tons of TA, and the annual production time is 7600 hours. The reaction conditions are given in Table 1.1.

[0026] Central temperature

[0027] The corresponding reactor structure and size are given in Table 1.2.

[0028] diameter (m)

[0029] In the table, D is the diameter of the tower, which is determined according to the production capacity, and H is the height of the reaction section. For a single air-lift external circulation bubble column reactor (ALECBCR) with an annual output of 200,000 tons of terephthalic acid, when the aspect ratio is selected to be 8, D = 3.68m, and the reaction results and related indicators are given in Table 1.3 In the table, the reaction indicators of the bubble column reactor (BCR) without external circulation pipe under the same conditions are also given for comparison.

[0030]...

Embodiment 2

[0033] The medium temperature oxidation process is used to produce terephthalic acid. The annual production capacity of a single reactor is still 200,000 tons of TA, and the annual production time is 7600 hours. The reaction conditions are given in Table 2.1.

[0034] Central temperature

degree(℃)

PX processing capacity

(10 3 kg / h)

Top pressure

(Mpa, absolutely

pressure)

tail oxygen concentration

Spend

(v O2 , %)

catalyst concentration

(to the mass fraction of HAc

number, 10 -6 )

h 2 O / HAc

(mass percentage)

Feed HAc / PX

mass ratio

co

mn

Br

185.0

17.72

1.168

3.50

691

406

892

7.52

4.66∶1

[0035] For the medium temperature oxidation process, when the aspect ratio is selected as 8, D=3.19m, and the structure and size of the reactor are given in Table 2.2

[0036] diameter (m...

Embodiment 3

[0040] The high-temperature oxidation process is used to produce terephthalic acid. The annual production capacity of a single reactor is still 200,000 tons of TA, and the annual production time is 7600 hours. The reaction conditions are given in Table 3.1. The structure and size of the reactor are shown in Table 3.2, and the output results of the reactor are listed in Table 3.3. Under the same reaction conditions and output results, the external circulation bubble reactor is 3.2% larger than the conventional bubble column reactor. The effect of the external circulation pipe in the above three cases is slightly different, which is mainly due to the difference in the size of the reactor and the external circulation pipe, resulting in different circulation flow rates.

[0041]

[0042] diameter (m)

[0043] PX conversion

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Abstract

The air lift externally circulation bubble tower oxidation apparatus includes cylinder bubble tower with top expanded section, outer circulating pipe, gas distributor, reflux liquid distributor and condensator. The outer circulating pipe has its upper end and lower end communicated with the upper part and the lower part of the bubble tower reaction section separately and is used to lead slurry from the upper part of the tower to the lower part via air lift effect so as to form the fluid circulation in the whole tower and complete the liquid phase catalytic oxidation of xylene. The bubble tower has relatively high height / diameter ratio and thus reinforced gas-liquid mass transfer and the air lift outer circulation pipe improves the temperature distribution and concentraion distribution inside the tower. The tower has no moving part, simple structure and low cost and is suitable for oxidizing xylene to prepare terephthalic acid via different technological processes.

Description

technical field [0001] The invention relates to an air-lift external circulation bubble tower oxidation device for producing terephthalic acid (TA), in particular to a device for air-liquid-phase catalytic oxidation of p-xylene (PX) in the production process. Background technique [0002] Terephthalic acid is an important raw material for the production of polyester (PET) fibers and resins. At present, it is mainly produced by the p-xylene air oxidation method. Or tetrabromoethane) in the acetic acid solvent, pass into air or enriched oxygen to carry out oxidation, generate solid product terephthalic acid. The typical reaction temperature is 155-205°C, the pressure is 0.5-1.6 MP, and the residence time is 40-120 minutes. The reaction heat is removed by solvent evaporation, and the steam is condensed and returned to the reactor. The resulting slurry is then obtained through subsequent separation and refining processes. Purified terephthalic acid (PT...

Claims

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Application Information

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IPC IPC(8): C07C51/265C07C63/26
Inventor 李希罗文德宋景祯谢刚
Owner CHINA TEXTILE IND ENG INST
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