Improved process of three-kettle polyester process

Abstract

The invention discloses an improved process of a three-kettle polyester process. Related equipment mainly comprises an esterification kettle, a pre-polymerization reaction kettle, a final polymerization kettle and an ethylene glycol-water separation tower, wherein the feeding amount of terephthalic acid and ethylene glycol slurry in the esterification kettle is 19.5 t / h; the material amount from the esterification kettle to the pre-polymerization reaction kettle is 13.1 t / h; according to an original process, two pipelines are led out from an outlet of an EG hot well; a pipeline is lead to thespraying condenser of the pre-polymerization reaction kettle after cooling and filtering, and the other pipeline is lead to a CP recover tank and a slurry mixing tank in sequence. A pipeline is additionally arranged in the outlet of an EG hot well so as to lead the material flow in the EG hot well to the ethylene glycol-water separation tower. A hand valve, a flow meter and a regulating valve arearranged on the pipeline. According to the technical scheme, the heat consumption of the device can be greatly reduced, the use amount of circulating water is saved, inactivation of a titanium catalyst is avoided, and the whole scheme is simple and feasible.

Description

technical field [0001] The invention belongs to the technical field of polyester production, and in particular relates to an improved process flow of a three-pot polyester process. Background technique [0002] The commonly used polyester production process is a three-pot process, that is, an esterification reactor, a prepolymerization reactor, and a final polycondensation reactor. reaction to produce an oligomer with an esterification rate of about 92%. Among them, the pre-condensation reaction is mainly carried out in the up-flow pre-condensation tank. The up-flow pre-condensation tank is composed of three parts. The bottom is a tubular heater, the middle part is composed of 16 trays with bubble caps, and the top is gas-liquid separation. device. [0003] PTA, EG, EG recovered from the system and titanium-based polyester catalyst are fully mixed in the slurry mixing tank, and then poured into the esterification kettle. The esterification kettle includes a heater and a ga...

AI Technical Summary

Problems solved by technology

The ethylene glycol in the CP recovery tank will enter the slurry mixing tank for slurry preparation, which will cause a large amount of water to enter the esterification tank, and the water entering the esterification tank will absorb a large amount of heat, and further from the esterification tank to gas-liquid The separation tank enters the ethylene glycol and water separation tower, and when it is separated from ethylene glycol in the tower, it needs to absorb heat, which is equivalent to repeated absorption of heat, resulting in increased energy consumption

In addition, too high water content will also affect the activity of titanium-based catalysts

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