Feeding method of recovery tower in dry-process continuous polymerization production technique of polyurethane

Abstract

The invention discloses a feeding method of a recovery tower in a dry-process continuous polymerization production technique of polyurethane. The method comprises the following steps: arranging a pneumatic regulation valve on a connection pipeline between a feeding tank and a recovery tower; additionally arranging a PLC liquid level interlocking control device between the pneumatic regulation valve and the liquid level of the recovery tower, wherein the PLC liquid level interlocking control device comprises a liquid level input signal module, a PID module and a pneumatic regulation valve output signal module; and adjusting the opening degree of the pneumatic regulation valve according to the height of the liquid level of the recovery tower so as to retain the liquid level of the recovery tower at a constant value. By utilizing the method, the process parameters of the recovery tower are stabilized; the discharging DMAC index is uniform and stable; the index difference between batches in the intermittent feeding manner is avoided; the DMAC index is stable; the discharging times and discharging quantity of hazardous wastes of the recovery tower are reduced; the environmental pollution is reduced; the process is automatically controlled; the labor of staff can be alleviated; the operability of the process is improved.

Description

【Technical field】 [0001] The invention belongs to the technical field of polymerization process, and specifically refers to a recovery tower feeding method in a spandex dry continuous polymerization production process. 【Background technique】 [0002] Spandex dry continuous polymerization production process is mainly divided into three processes. [0003] Polymerization process: The purpose of the polymerization process is to prepare spinning dope that meets the requirements of the spinning process for the spinning process. The continuous polymerization process is adopted: the prepolymer is first synthesized, and then the chain extender and terminator are added for reaction to form a block copolymer with a molecular weight between 20,000 and 50,000. [0004] Spinning process: In the pre-spinning preparation process, the polymer stock solution passes through the filter and enters the spinning storage tank. The stock solution sent from the spinning tank is transported to the ...

AI Technical Summary

Problems solved by technology

Since the bottom of the recovery tower contains impurities and reboilers, when the liquid level of the recovery tower is at a low level, it is particularly easy to rectify the particles of these reboilers into the DMAC, resulting in a particularly high conductivity and acid value of the DMAC; With different liquid levels, the DMAC indexes distilled out are also different, and the index differences between batches are relatively large

When the indicators are not up to standard, hazardous waste must be discharged, resulting in an increase in the number of hazardous waste and an increase in the amount of hazardous waste

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