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Built-in micro-interface oxidation system and built-in micro-interface oxidation method for preparing terephthalic acid from p-xylene

A terephthalic acid and oxidation system technology, applied in the field of built-in micro-interface oxidation system, can solve the problems of difficulty in obtaining a breakthrough improvement in reaction performance, limited phase boundary area and mass transfer coefficient, and affecting the overall efficiency of the reaction. The effect of equipment operation cycle, ensuring industrialized large-scale production, and reducing investment intensity

Active Publication Date: 2020-08-25
NANJING YANCHANG REACTION TECH RES INST CO LTD
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Terephthalic acid is an important chemical raw material, usually produced by the oxidation reaction of p-xylene and oxygen-containing gas. The reactor for p-xylene oxidation usually adopts a bubbling oxidation reactor, and the direct bubble is usually larger than 3mm, or even At the centimeter level, the area of ​​the mass transfer boundary phase is limited, and the gas utilization rate is low so that the reaction efficiency is low. In order to strengthen the gas-liquid mass transfer, the bubbling reactor generally adds internals such as trays and static mixers in the tower to enhance mixing. However, the diameter of the bubbles after mixing is usually 3-30 mm, and the provided phase boundary area and mass transfer coefficient (liquid side, gas side) are limited, so it is difficult to obtain a breakthrough improvement in reaction performance, which in turn affects the overall efficiency of the reaction. Therefore, high temperature and high pressure operations have to be used in engineering to increase the mass transfer rate by increasing the solubility of the gas phase and / or liquid phase, thereby strengthening the reaction process. However, the process of p-xylene oxidation is very complicated, mainly including 4 steps, namely p-xylene oxidation. Toluene (PX) → p-toluene (TALD) → p-toluic acid (p-TA) → p-carboxybenzaldehyde (4-CBA) → terephthalic acid (TA), the first two steps should be acetic acid As a solvent, it is not suitable to use high temperature and high pressure. The prior art adopts a mixed reaction process, which has high energy consumption, large consumption of acetic acid, and low reaction efficiency.

Method used

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  • Built-in micro-interface oxidation system and built-in micro-interface oxidation method for preparing terephthalic acid from p-xylene
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Embodiment

[0062] refer to figure 1 As shown, the built-in micro-interface oxidation system for preparing terephthalic acid from p-xylene includes a first reactor 10 , a rectification column 20 and a second reactor 30 .

[0063] Wherein, the side wall of the first reactor 10 is provided with a first outlet 11, and a second inlet 12 and a mixed raw material inlet 14 are provided at a position lower than the opposite side wall, and a second outlet 13 is provided at the top of the first reactor 10. The material that the second outlet 13 comes out mainly contains acetic acid and steam.

[0064] The side wall of the rectifying tower 20 is provided with a material inlet 21, and the bottom is provided with a material outlet 22. The side wall of the second reactor 30 is provided with a first inlet 31 at the lower position, and the other side is provided with an air inlet 33. The first outlet 11 is connected with the material inlet 21, and the first inlet 31 is connected with the material outlet...

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Abstract

The invention provides a built-in micro-interface oxidation system for preparing terephthalic acid from p-xylene. The oxidation system comprises a first reactor, a rectifying tower and a second reactor which are sequentially connected, wherein a first outlet is formed in the side wall of the first reactor; a first inlet is formed in the side wall of the second reactor; a material inlet is formed in the side wall of the rectifying tower; a material outlet is formed in the bottom of the rectifying tower; the first outlet is connected with the material inlet of the rectifying tower; the first inlet is connected with the material outlet of the rectifying tower; micro-interface units are arranged in the first reactor and the second reactor; and the micro-interface units are used for dispersingbroken air into bubbles. According to the built-in micro-interface oxidation system, the micro-interface units are arranged in the reactors, and a sectional process is adopted, so the problems of highenergy consumption, high raw material consumption and low reaction efficiency in traditional processes are solved, and the effect of saving cost for enterprises is achieved.

Description

technical field [0001] The invention relates to the field of oxidation reactions for preparing terephthalic acid from p-xylene, in particular to a built-in micro-interface oxidation system and method for preparing terephthalic acid from p-xylene. Background technique [0002] Terephthalic acid is an important chemical raw material, usually produced by the oxidation reaction of p-xylene and oxygen-containing gas. The reactor for p-xylene oxidation usually adopts a bubbling oxidation reactor, and the direct bubble is usually larger than 3mm, or even At the centimeter level, the area of ​​the mass transfer boundary phase is limited, and the gas utilization rate is low so that the reaction efficiency is low. In order to strengthen the gas-liquid mass transfer, the bubbling reactor generally adds internals such as trays and static mixers in the tower to enhance mixing. However, the diameter of the bubbles after mixing is usually 3-30 mm, and the provided phase boundary area and m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D3/00B01J19/24C07C51/265C07C63/06
CPCB01D3/009B01J19/245C07C51/265C07C63/06C07C67/39C07C67/54B01D3/143C07C69/82B01D3/14B01D5/0063B01J4/001B01J10/002B01J2204/002B01J2204/005
Inventor 张志炳周政张锋李磊孟为民王宝荣杨高东罗华勋杨国强田洪舟曹宇
Owner NANJING YANCHANG REACTION TECH RES INST CO LTD
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