Automatic control method for reaction kettle for producing cellulose ether

Abstract

The invention relates to an automatic control method for a reaction kettle for producing cellulose ether. In the automatic control method, a charging control system and a temperature control system are adopted. Two sensors for tracking variation of a temperature of materials in the reaction kettle in the reaction process are arranged in the reaction kettle. The sensors are respectively connected with a kettle temperature controller and a computer. The automatic control method is characterized in that when the temperature is risen, a hot water valve is opened; when the kettle temperature is lower than a kettle temperature set value, the hot water valve is closed to stop filling hot water and a cold water valve is opened to repeatedly replace jacket water, so that a temperature of a jacket is reduced to a jacket temperature set value; when the temperature is close to a reaction constant temperature, a constant temperature control mode is automatically switched to carry out PID (Proportion Integration Differentiation) cascade regulation and control by a discrete control method; and after the reaction is finished, the cold water valve is opened and the temperature is reduced to a discharging temperature set value and the materials are discharged. The automatic control method for the reaction kettle for the producing cellulose ether has the characteristics of effectively reducing the labor intensity, improving the charging accuracy, improving the safety, avoiding a personal error and the like.

Description

technical field [0001] The invention relates to an automatic control method for producing a cellulose ether reaction kettle. Background technique [0002] At present, in the process of producing cellulose ether (HPMC, HEC, CMC, PAC, HPC) by the domestic slurry method, the control of the reactor is all manual control or general instrument control, and the accuracy of feeding is very low (generally within 5- 10 kg deviation), the control process is more complicated and labor-intensive, and one reactor requires two operators; the control accuracy is low, and the temperature difference in the constant temperature stage of the reaction process is 3-6°C; the operator's proficiency is required. , Only operators with more than 3 years of work experience can operate proficiently. The operation deviation between people is relatively large, resulting in large fluctuations in product quality, and the quality stability of products cannot be guaranteed. Contents of the invention [000...

AI Technical Summary

Problems solved by technology

[0002] At present, in the process of producing cellulose ether (HPMC, HEC, CMC, PAC, HPC) by the domestic slurry method, the control of the reactor is all manual control or general instrument control, and the accuracy of feeding is very low (generally within 5- 10 kg deviation), the control process is more complicated and labor-intensive, and one reactor requires two operators; the control accuracy is low, and the temperature difference in the constant temperature stage of the reaction process is 3-6°C; the operator's proficiency is required. , Only operators with more than 3 years of work experience can operate proficiently. The operation deviation between people is relatively large, resulting in large fluctuations in product quality, and the quality stability of products cannot be guaranteed.