| The batch reaction process is generally a time-varying system,and the internal reaction mechanism is complex,and there are characteristics such as nonlinearity,multivariable,and large hysteresis,which makes the control of the batch reactor become a key technical problem.The synthesis process of tetrahydrofuran is a repetitively semi-continuous and semi-batch production process.The control of reactor temperature is a major factor that directly affects product quality and yield.The carbonylation reaction of dihydrofuran is an exothermic reaction,whose reaction system has large capacity,and there are problems such as temperature measurement and transmission lag,etc.It is difficult to meet the requirements of control quality by adopting conventional control strategies.Therefore,it is urgent to use advanced control technology to solve such complicated object control issues.In this paper,an advanced control strategy was developed for the synthesis process of a company’s tetrahydrofuran.Through the design and integration of the whole computer control system,it was applied in the process of carbonylation reaction,which achieved satisfactory results and effectively improved the intelligent manufacturing level of the production process.The work of this paper is carried out from the following aspects:(1)The characteristics,control requirements and control difficulties of the intermittent production process were reviewed and summarized.The research progress and application status of advanced control technology in batch reaction production were summarized.(2)The reaction mechanism and production process of methanol water gas,cyclization reaction and dihydrofuran carbonylation reaction were studied in detail,and the key process control of batching,feed,nitrogen replacement and carbonylation reaction in the carbonylation reaction process was comprehensively analyzed.By the analysis of the main points of the reaction process,it was further proposed that the control of reaction temperature was regarded as core requirements,laying a good foundation for the overall design of the reaction process control system.(3)Based on the repetitive characteristics of the synthesis process of tetrahydrofuran,an iterative learning control technique based on open-closed-loopPID algorithm was developed.According to the heat balance relationship of the reactor,feedforward compensation was introduced,and the output of the PID controller was corrected by iterative learning.The simulation results of the control technology showed that the temperature control achieved satisfactory control effect.Even though the system existed output interference and offset at initiation,the temperature trajectory could completely track the desired trajectory,and the control precision can be reached the scope of the process request.(4)The SUPCON JX-300 XP distributed control system was used to complete the computer control system integration and engineering implementation of the tetrahydrofuran synthesis process.According to the requirements of the production process,the design and configuration of each control system was finished.Subsequently,the corresponding hardware configuration of the control station,the hardware and software configuration of the operation station and the configuration of the auxiliary components were determined.Apart from this,the module configuration of the gas making control system,the module configuration of the cyclization reaction control system,the module configuration of the carbonylation reaction control system,the data exchange between the control stations and the module configuration of the safety production control system were completed.Finally,through system installation and debugging,the real-time monitoring and control of the main parameters of the production process was successfully realized,which ensured the improvement of production quality and safe operation,and provided a basic platform for further research on the overall system optimization and energy saving of the synthesis process. |
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