Research On Cross-Exchanger And Liquefaction Cooling Control Based On Honeywell PKS System

As a type of heat transfer equipment,heat exchangers are widely used in largescale projects such as chemical,metallurgical,and petroleum industries.Conventional PID control is difficult to meet the dynamic and steady-state performance requirements for the non-linear and highly lagged control system of heat exchanger outlet temperature.In order to solve this problem,this project takes the 300,000 tons/year fuel ethanol relocation and transformation project of a biochemical fuel alcohol limited company as the background,and proposes a control scheme combining expert control system and PID control for the heat exchanger in the liquefaction unit,which is designed and implemented in the Honeywell PKS software.Firstly,the process flow of the heat exchanger equipment in the liquefaction unit is introduced,and the control requirements for the heat exchanger outlet temperature are determined.In order to better analyze the heat transfer process,an experimental modeling scheme is proposed,and the open-loop experiment is performed on the controlled object to obtain an approximate model of the heat exchanger system.In the parameter identification stage,the artificial bee colony algorithm is adopted,and the curve obtained after identification is very close to the curve obtained from the openloop experiment,thereby obtaining the accurate transfer function of the heat exchanger.Secondly,in order to verify the superiority of the expert PID controller,a simulation experiment is conducted on the heat exchanger outlet temperature control system.The conventional PID parameters are tuned by trial and error method,and the simulation results show that the conventional PID can improve the system stability,but the control accuracy cannot reach the ideal effect.In order to overcome the shortcomings of conventional PID control,an expert PID control scheme is proposed.Based on the conventional PID,the expert PID controller is designed by combining practical engineering experience.The simulation results show that compared with the conventional PID control,the expert PID control algorithm reduces the system overshoot,improves the system stability,and can reach the steady-state value faster,with better control effect.Finally,in order to verify the feasibility of the control scheme in practical engineering,the Honeywell PKS control system is built.In the system,an expert PID function block is designed and developed.At the same time,the control algorithm switching function is added in combination with the actual engineering needs,and the configuration work of the expert PID function block is completed.The on-site debugging and operation of expert PID control is realized,and the running results are basically consistent with the simulation effect.In conclusion,the expert PID control scheme designed for the heat exchanger outlet temperature has achieved the desired control effect,and has been tested in practical engineering through the Honeywell PKS system,verifying the feasibility and practical significance of this control scheme for the cooling control of heat exchanger outlet temperature.