PBT(polybutylene terephthalate) esterification reaction system

Abstract

The invention relates to a PBT (polybutylene terephthalate) esterification reaction system, which comprises a slurry finished product tank, a catalyst tank, an esterification reaction kettle, a pre-condensation reaction kettle and a final condensation reaction kettle, wherein a discharging opening of the slurry finished product tank is connected with a slurry inlet of an esterification kettle; a discharging opening of the esterification kettle is connected with a feeding opening of a pre-condensation kettle; a discharging opening of the pre-condensation kettle is connected with a feeding opening of the final condensation kettle; a catalyst inlet arranged at the bottom of the esterification reaction kettle is provided with a catalyst bottom injection valve; a barrel pump outlet built in a catalyst barrel is connected with a feeding opening of the catalyst tank through a barrel pump output pipe; an air inlet on the top of the catalyst tank is connected with a nitrogen pipe; a dischargingopening of the catalyst tank is connected with an inlet of a catalyst metering pump; an outlet of the catalyst metering pump is connected with a material inlet of a catalyst heater through a catalystfilter; a material outlet of the catalyst heater is connected with an inlet of the catalyst bottom injection valve through a catalyst bottom injection pipe. The catalyst of the system does not need to be mixed with BDO (1,4-butanediol) for preparation; hydrolysis or pipeline blockage is not liable to occur; the continuous production can be ensured.

Description

technical field

[0001] The invention relates to a PBT production system, in particular to a PBT esterification reaction system, and belongs to the technical field of polyester production equipment. Background technique

[0002] Polybutylene terephthalate, referred to as PBT, belongs to the series of polyesters. It is formed by reacting 1,4-butanediol (BDO) and terephthalic acid (PTA) in an esterification reactor to form terephthalic acid bis Hydroxybutyl ester (BHBT) and higher molecular oligomers and water and BDO are cyclized at high temperature to generate tetrahydrofuran (THF), and then enter the polycondensation reaction, which includes pre-condensation and final polycondensation.

[0003] The catalyst for PBT polymerization production is tetrabutyl titanate, which is easily hydrolyzed when it encounters water, loses its activity, and at the same time generates titanium hydrate, which is easy to block the pipeline and affect the addition of the catalyst. Tetrabutyl tit...

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