Treatment process for mother liquor extraction liquid of purified terephthalic acid oxidation unit

Abstract

The invention relates to a treatment process for a mother liquor extraction liquid of a purified terephthalic acid oxidation unit, and belongs to the field of industrial wastewater treatment. The process comprises the steps that the oxidized mother liquor extraction liquid is treated by an acetic acid recovery unit or a terephthalic acid partial recovery unit and a temperature-reducing solid-liquid separation unit. A separation liquid passes through an impurity removal unit, a resin cobalt and manganese adsorption unit for recovering cobalt and manganese and a bromine removal unit for recovering bromine, and finally, waste liquid is directly discharged to a comprehensive sewage treatment unit; solids are washed with water at first, a water washing liquid is conveyed to the resin cobalt andmanganese adsorption unit to recover the cobalt and manganese, and the remaining solids are recovered and extracted and purify terephthalic acid and benzoic acid, and economic value is generated. Theconcentration of bromine, benzoic acid, phthalic acid and other benzene-series compounds in the oxidized mother liquor extraction liquid is reduced, the adverse effects on the activity of biochemicalsludge are avoided, the difficulty of treating wastewater is reduced, and the efficiency of later comprehensive sewage treatment is improved; the consumption quantity of alkaline substances is reduced, the resources are saved, the enterprise cost is reduced, and the utilization rate is increased.

Description

Technical field [0001] The invention belongs to the field of industrial wastewater treatment, and specifically relates to a treatment process for a mother liquor extraction liquid of a purified terephthalic acid oxidation unit. Background technique [0002] Purified terephthalic acid is an important raw material for polyester production, so it is widely used in industry. The oxidation unit of purified terephthalic acid will have a mother liquor extraction liquid. At present, the more conventional method of such factories is to recover acetic acid from this mother liquor extraction liquid, or to add alkaline substances after passing through the terephthalic acid partial recovery processing unit ( Generally use carbonate, bicarbonate, hydroxide) to dissolve benzene series such as phthalic acid and benzoic acid; precipitation to remove iron and chromium ions; precipitation of cobalt and manganese recovery (cobalt and manganese are the oxidation of purified terephthalic acid Unit ca...

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Problems solved by technology

[0003] The purpose of the patent of the present invention is to solve the defects of the large amount of alkaline substances used in the prior art, which cause the increase of enterprise cost and the waste of resources, by treating the extracted liquid of the oxidation mother liquor, and specifically relates to a kind of mother liquor extraction for purified terephthalic acid oxidation unit liquid treatment process

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