Design And Implementation Of PKS Ethanol Fermentation Temperature Control System

With the rapid growth of the global economy and continuous development of industrialization,the consumption of petrochemical energy has increased significantly,making the development of green renewable energy a research hotspot.Therefore,fuel ethanol has been widely promoted and used.In the ethanol production process,fermentation temperature is an important factor affecting fermentation efficiency and product quality.Therefore,based on the 300,000-ton/year fuel ethanol relocation and transformation project of a certain biochemical fuel alcohol company,this project introduces the Dynamic Matrix Control(DMC)algorithm to address the poor performance of conventional PID controllers in fermentation temperature control.The Honeywell PKS(Process Knowledge System)system is used to design and optimize the ethanol fermentation temperature control system,improving its control performance.Firstly,the ethanol fermentation process is introduced,the principle of fermentation temperature control is explained,and the open-loop step response curve of corn fermentation temperature control process is obtained through engineering actual debugging process.Combined with the temperature change curve,it is analyzed that the system can be approximately represented by a second-order pure lag model.The transfer function model of the controlled object is obtained through parameter identification of the acquired data.Simulation is carried out in Matlab and the fitting effect is good when compared with the actual step response curve,verifying the accuracy of the transfer function model.Secondly,in view of the characteristics of corn fermentation temperature control,conventional PID control parameter tuning is difficult,and it is sensitive to changes in controlled object parameters,with undesirable control effects such as overshoot and long settling time.Therefore,in order to optimize the control of the main parameters of the fermentation process,predictive control technology needs to be introduced.Through comparison and analysis of simulation results of conventional PID and DMC in Matlab,it is known that the accuracy and stability of DMC are better than those of conventional PID control.Finally,the hardware and software design of the Honeywell PKS ethanol fermentation temperature control system,as well as system operation and debugging,are carried out.In the PKS system,the conventional PID controller is configured according to the empirical method,and the control parameters of the conventional PID are tuned to meet the control requirements of ethanol fermentation temperature.The DMC function block is designed using the Custom Algorithm Block(CAB),and the control parameters obtained from the Matlab simulation process are introduced into the DMC function block to achieve the function of dynamic matrix predictive control.During the engineering debugging period,the DMC function block is applied to the ethanol fermentation temperature control system,and the actual DMC temperature control curve is obtained.In conclusion,through the analysis of the running results,the DMC algorithm can effectively improve the accuracy and speed of ethanol fermentation temperature control,and improve ethanol fermentation efficiency.It has been verified that the DMC control scheme proposed for ethanol fermentation temperature control is feasible and has certain significance in the ethanol fermentation temperature control engineering.