Dissolution processing method for CTA draff in PTA production

Abstract

The invention relates to a solvent processing method for CTA residue during the PTA production. The method comprises the following steps: mixing the CTA residue and water into slurry which is dissolved and filtrated to obtain mixed acid filter cake and hot crude benzoic acid filtrate; injecting the obtained hot crude benzoic acid filtrate into a cooling pond for natural cooling and crystallization, and obtaining crude benzoic acid filter residue and aqueous solution after filtration; injecting the obtained crude benzoic acid filter residue into a sintering kettle for heating and melting, and obtaining a big block of crude benzoic acid after cooling and recrystallization in a reception tray; and adding the obtained big block of the crude benzoic acid into a distillation tower for benzoic acid distillation, and obtaining the industrial-grade benzoic acid from the top of the tower through the heat exchange and separation of filler gas liquid in the distillation tower. The method which carries out the synthesized processing of the CTA residue in the PTA production through the solvent processing method can sufficiently extract various valuable constituents in the CTA residue, thereby not only solving the problem of processing the CTA residue during the PTA production, but also creating great economic benefits. Therefore, the method has high promotion and application values.

Description

technical field [0001] The invention relates to a method for recycling residues in petrochemical production, in particular to a method for dissolving CTA residues in PTA production. Background technique [0002] In the PTA (purified terephthalic acid) plant, when PX (p-xylene) is oxidized to generate CTA (crude terephthalic acid), a large number of side reactions occur, and the generated by-products and unreacted raw materials enter the mother liquor , The solid impurity produced after the mother liquor is evaporated to recover acetic acid is called CTA residue. [0003] The composition of CTA residue is complex, and its composition often changes. It mainly contains the following components: benzoic acid, terephthalic acid, isophthalic acid, phthalic acid, other organic substances, and Co, Mn organic salt catalysts, etc. The components are complex and the composition is not fixed, and the cost of recycling and processing is high, so people usually use the following methods ...

AI Technical Summary

Problems solved by technology

[0006] The above-mentioned first method of recycling CTA residue is only to recycle one component in the residue, and other components are discarded as residue again, and its treatment is also a great environmental problem; the second method of recycling CTA residue adopts Esterification will consume a large amount of alcohol and other raw materials, not only the recovery cost is high, but also the process is relatively complicated, making it difficult to popularize and use