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Method for treating separated mother liquor from terephthalic acid refinement

A terephthalic acid and treatment method technology, which is applied in the field of treatment of purified terephthalic acid separation mother liquor, can solve problems such as large distillation load, achieve the effects of reducing environmental load, reducing treatment costs, and improving efficiency

Inactive Publication Date: 2014-05-07
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] In addition, evaporation is considered as a method for treating this secondary mother liquor, and in order to minimize evaporated water together with accompanying pollutants (p-tA, etc.), a treatment method of fractional distillation with a sufficient reflux ratio has been proposed, but due to In fractional distillation treatment (reflux ratio 2-10, theoretical number of stages 25-12), with sufficient reflux ratio to distill water with high latent heat of evaporation (latent heat of evaporation 539kcal / kg, 100°C), the distillation load is large

Method used

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  • Method for treating separated mother liquor from terephthalic acid refinement
  • Method for treating separated mother liquor from terephthalic acid refinement
  • Method for treating separated mother liquor from terephthalic acid refinement

Examples

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Embodiment 1

[0064] High temperature, high pressure (about 145°C, about 3Kg / cm 2 The primary mother liquor of G) is adjusted to a ratio of about 500ml / min by valve V1 (flow meter M), and is directly introduced into the liquid in autoclave A, and flashed at atmospheric pressure (ATM). At the same time, about 6 ml of 20% by weight terephthalic acid slurry was injected into the feeding pipe 21 of the primary mother liquor through the pipe 29 with a quantitative injector H at intervals of 1 minute.

[0065] It was flashed for about 1 hour (without reflux), and as a result, condensed water (8.2% by weight relative to the primary mother liquor) was obtained at a rate of about 41 ml / min from the condensate receiving tank D. The content of p-toluylic acid (para-toluylic acid) in the evaporated condensed water was 2.1 ppm. Here, relative to 0.17% by weight of terephthalic acid dissolved in the primary mother liquor at 145°C (the solubility of terephthalic acid is 0.17gr / 100gr water), the supply of...

Embodiment 2

[0069] The introduction of the primary mother liquor and the injection of the terephthalic acid slurry were performed in the same manner as in Example 1, and the pressure in the autoclave A was maintained at a reduced pressure of 150 mmHg, and the temperature was maintained at about 60° C., and the same as in Example 1. Flash cooling. At this time, 102 ml / min of evaporated condensed water (20.4% by weight relative to the primary mother liquor) was obtained from the condensate receiving tank D, and the content of p-toluic acid was 2.7 ppm.

Embodiment 3

[0073] After the flash evaporation in Example 2 is completed, close V1 and V2 (stop the injection of the mother liquor and the discharge of the suspended mother liquor), maintain the pressure in the autoclave A at 150 mmHg, maintain the temperature at about 60 ° C, and do not reflux the autoclave Evaporation and concentration are carried out by evaporating and concentrating the evaporating steam of the suspended mother liquor in the water (condensation cooler C1 does not pass cooling water).

[0074] The evaporated condensed water was stored in the condensed liquid receiving tank D, and the amount of 5.6 L of condensed water distilled out after the start of this concentration was calculated and measured, and then approximately 100 ml of condensed water was extracted from the sample tube S. The content of p-toluic acid in the sample condensed water was 4.3 ppm. Here, since the capacity of the suspension mother liquor remaining in the autoclave A after the flash evaporation in E...

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Abstract

Provided is a method for treating the separated mother liquor from terephthalic acid refinement whereby recovered water with little impurity is obtained cheaply and in large quantity from the primary mother liquor separated at the time of primary crystallization. The method of treating the mother liquor (primary mother liquor) wherein the refined terephthalic acid crystals (primary crystals) and mother liquor (primary mother liquor) are separated from the crystal slurry involves an evaporation process wherein the aforementioned mother liquor is evaporated in the presence of terephthalic acid crystals by heating and flash evaporation at a pressure below atmospheric pressure and separated into vapor and a mother liquor suspension of terephthalic acid crystals; a process whereby terephthalic-acid-containing crystals are separated from the aforementioned mother liquor suspension; and a process whereby the aforementioned vapor is condensed and condensed water is produced.

Description

technical field [0001] The present invention relates to a method for treating the primary mother liquor separated from the purified terephthalic acid crystal slurry into crystal and mother liquor when producing high-purity terephthalic acid. The present invention is to effectively treat a large amount of separated mother liquor (primary mother liquor) discharged from purified terephthalic acid crystallization in the production of high-purity terephthalic acid, so that it can be reused, has a small environmental load, and saves resources technology, wherein the production of the high-purity terephthalic acid comprises: after performing an oxidation reaction of p-xylene in a liquid phase in the presence of an oxidation catalyst in an acetic acid solvent to produce crude terephthalic acid, the crude terephthalic acid is Dissolve terephthalic acid in high-temperature, high-pressure water, and carry out hydrogenation purification in the presence of a precious metal catalyst to obta...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/43C07C51/44C07C63/26
CPCC07C51/43
Inventor 原德明丰岛弘幸山崎初太郎
Owner HITACHI LTD