Water-rich solvent classification utilization emission reduction system for preparing terephthalic acid

A technology of terephthalic acid and water solvent, which is applied in the field of water-rich solvent classification and utilization and emission reduction system, can solve the problems of unreasonable selection of mother liquor reflux position, reduction of rectification separation efficiency, and high loss of acetic acid, etc. Energy consumption, the effect of reducing consumption

Active Publication Date: 2019-08-02
杭州多向流化学科技有限公司 +1
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  • Abstract
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Problems solved by technology

[0014] In summary, the drawbacks of the existing PTA process that adopts the direct distillation of oxidation reaction tail gas are that the content of acetic acid in the liquid obtained from the distillation is high, resulting in a large loss of acetic acid in the discharge liquid

Method used

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  • Water-rich solvent classification utilization emission reduction system for preparing terephthalic acid
  • Water-rich solvent classification utilization emission reduction system for preparing terephthalic acid
  • Water-rich solvent classification utilization emission reduction system for preparing terephthalic acid

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Embodiment

[0057] The process flow of the water-rich solvent classification utilization emission reduction system used to prepare terephthalic acid in this embodiment is as follows figure 2 As shown, it mainly includes: oxidation reactor unit, dehydration rectification unit, energy recovery unit 5, oxidation crystallization unit, oxidation filtration unit, refining batching unit, hydrogenation and crystallization unit, refining filtration and drying unit, water solvent stripping unit , multi-effect evaporation unit and other subsystems.

[0058]Oxidation reactor unit: the p-xylene raw material is sent to the oxidation reactor 1 through the pipeline, and the filtrate from the oxidation filter 9 provides a circulating mother liquor, which contains a small amount of uncrystallized terephthalic acid and a large amount of solvent acetic acid and recycled In addition, a small amount of catalyst is added to the oxidation reactor 1. The compressed air is passed into the oxidation reactor 1 thr...

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Abstract

The invention discloses a water-rich solvent classification utilization emission reduction system for preparing terephthalic acid, which comprises a plurality of units, such as oxidation reaction, rectification dehydration, oxidation and purification filtration, solvent stripping, multi-effect distillation and the like. According to the system, through the optimized configuration of materials, water-rich solvents with different levels of acetic acid concentration are classified and utilized, and on the premise of ensuring product quality and effectively utilizing the reaction heat, the use amount of fresh water is greatly reduced and the organic matter content in a discharged liquid is reduced. The key technology lies in that: (1) a dehydration unit is provided with a three-stage rectifying column, the water-rich solvent produced by each unit in the oxidation and refining process is re-circulated to the rectifying columns according to a concentration matching rule, and the water-rich solvents obtained by rectification are respectively used for oxidation filter washing, refining filter washing, exhaust gas spraying and the like as required by different acetic acid concentrations; (2) self-produced low-pressure steam of the system is utilized for multi-effect distillation of the discharged liquid, thereby fully recovering acetic acid in the discharged liquid, and reducing systemacetic acid consumption.

Description

technical field [0001] The invention relates to the technical field of clean production, in particular to an emission reduction system for graded utilization of water-rich solvents used for preparing terephthalic acid. Background technique [0002] Terephthalic acid (Pure Terephthalic Acid, PTA) is the main raw material of chemical fibers and polyester bottle flakes, which is prepared by the liquid-phase air oxidation method of p-xylene (PX), and its process mainly includes the following units: [0003] Step 1: Air oxidation, the oxidation reaction uses a stirred tank or a bubble column reactor. Under the three-way catalytic condition of cobalt, manganese and bromine, the phenylcyclomethyl group of the PX molecule is combined with oxygen to produce terephthalic acid, and a small amount of unreacted PX is transformed into the impurity p-carboxybenzaldehyde (4-CBA). The oxidation reaction is strongly exothermic and the heat of reaction is removed from the reactor by evaporati...

Claims

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Application Information

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IPC IPC(8): C02F9/10C02F103/36
CPCC02F1/001C02F1/04C02F1/72C02F9/00C02F2103/36C02F2303/10Y02P20/50
Inventor 王丽军黄耀智黄浩陈伟锋宁术余秦伟成有为李希
Owner 杭州多向流化学科技有限公司
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