Method for separating and refining industrial benzoic acid from PTA (pure terephthalic acid) process wastewater

Abstract

The invention discloses a method for separating and refining industrial benzoic acid from PTA (pure terephthalic acid) process wastewater. The method includes following steps: (1), heating PTA process wastewater to 95-105 DEG C, and obtaining terephthalic acid solid and mixed liquid containing benzoic acid, cobalt and manganese by centrifugal separation; (2), cooling the mixed liquid containing benzoic acid, cobalt and manganese by a jacketed reactor, and filtering the mixed liquid after cooling by adopting a diaphragm plate-and-frame filter press to obtain a benzoic acid elementary product; (3), drying the benzoic acid elementary product by a belt-type dryer; (4), placing the benzoic acid elementary product after drying into a premelting kettle for heating to 100 DEG C to 110 DEG C for vacuum dehydration; (5), placing the benzoic acid elementary product after vacuum dehydration into a fractionating tower, heating and fusing to be in a liquid state, continuing to heat for vaporization, and cooling the product after vaporization by a condenser; and (6), inputting the product after condensation into a slicing machine, using the slicing machine to cool for flaking, and obtaining the industrial-level benzoic acid finished product. The method for separating and refining the industrial benzoic acid from the PTA process wastewater is high in recovery, low in energy consumption, capable of recycling heat, energy-saving and environment-friendly.

Description

technical field [0001] The invention discloses a method for separating and refining industrial benzoic acid from PTA process wastewater. Background technique [0002] The treatment of oxidation residues and waste water produced in the production process of terephthalic acid (PTA) has always been a difficult problem in environmental protection. In the process of PTA production, the waste water produced contains a large amount of benzoic acid, terephthalic acid and isophthalic acid. In addition to organic compounds such as cobalt and manganese salts, it also contains inorganic compounds such as cobalt and manganese salts. Among them, cobalt acetate and manganese acetate are catalysts in the production of terephthalic acid. After the catalyst is used for a period of time, its catalytic activity weakens and is discharged along with the beating wastewater. When treating wastewater and oxidation residues, its technical core includes the separation and purification of benzoic aci...

AI Technical Summary

Problems solved by technology

Other units such as Liaoyang Petrochemical, Yizheng Chemical Fiber, and Luoyang Petrochemical have published articles. Although their processes are different, it is difficult to separate terephthalic acid from benzoic acid.