Fractionators narrowing polyester polyol molecular weight distribution

Abstract

A fractionators narrowing polyester polyol molecular weight distribution is disclosed. A wastewater collection tank (7) is installed adjacent to a polyester reaction vessel (2), also a reflux pipe is connected between the upper end of the polyester reaction vessel (2) and the lower end of a dephlegmator (4), the reflux-pipe segment is provided with a U-shaped pipe (5), the communication bottom end of the U-shaped pipe (5) is connected with the wastewater collection tank (7), and the bottom of a condenser is connected with the wastewater collection tank (7); the dephlegmator (4) is connected with the condenser (6), the polyester reaction vessel (2) is connected with the dephlegmator (4), a return valve is arranged at the pipeline connecting the U-shaped pipe (5) with the polyester reaction vessel (2). The product quality is improved, alcohol removal labor hour is saved, the processing time of 6 KL of the raw material is shortened within 1 h from original 3-5 h, micromolecule alcohols are rapidly efficiently removed, polyester polyol molecular weight distribution is properly narrowed, and the molecular weight distribution index is relatively small. The cobalt-platinum colour is relatively low, and the acid value is relatively low and is within 0.1 mg KOH / g.

Description

Technical field [0001] The present invention relates to a fractionation tower device in IPC classification B01D3 / 32 separation technology, which belongs to the structural improvement technology of polyester polyol reactor fractionation condensation equipment, especially a fractionator that narrows the molecular weight distribution of polyester polyol. Background technique [0002] Polyester polyols are usually polymerized through transesterification reaction between organic dicarboxylic acids, acid anhydrides or esters and polyols, including diols, triols, etc. Dicarboxylic acids include adipic acid, phthalic acid or phthalic anhydride, halophthalic acid, etc. Polyols include 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol, trimethylolpropane, pentaerythritol, etc. Different types of polyester polyols have different properties due to their different types and structures. The more important indicators of polyester polyols include hydroxyl value, acid val...

AI Technical Summary

Problems solved by technology

The original equipment structure is realized by heating the fractionator and increasing the vacuum degree. This method has long working hours and high energy consumption.

[0010] When the existing equipment structure removes excess small molecule alcohol, it is necessary to increase the temperature of the fractionator and increase the vacuum degree to allow the excess small molecule alcohol to flow into the waste water collection tank through the fractionator, which not only requires long working hours and high energy consumption, but also The thermal oxidation of polyester polyol at high temperature will also lead to the deepening of the color of polyester products, which will affect the appearance and quality

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