Research On Supercritical Fluid Extraction Technology And Its Measurement And Control Technology

CO₂ supercritical extraction?supercritical fluid extraction?is a new green technology.It has attracted wide attention since it appeared.It has been applied in the field of petroleum,medicine and other industries and has been widely recognized by all walks of life.Comparing with the previous research data,we found that there are many factors that influence the supercritical extraction process,such as temperature,pressure,solvent flow rate,material property and so on.In this paper,the extraction of Schisandra chinensis was used as the research object to explore the significant factors in the supercritical extraction process,and to explore an optimal experimental condition,and to model and simulate the control process of supercritical extraction,so as to make the extraction rate as possible as possible to the highest state.The main work of this article is as follows:On the basis of CO₂ supercritical extraction technology,the nutritional value and application prospect of Schisandra chinensis were analyzed in this paper,and the process control of Schisandra chinensis by CO₂ supercritical extraction was determined as the research object.The characteristics of several common methods,such as water agent method,leaching method and pressing method,are compared and analyzed.The advantages and disadvantages of the traditional methods are summarized and compared with the supercritical extraction.The supercritical extraction of CO₂,such as temperature,pressure,CO2 flow,and so on,is analyzed by experiments.The optimum value of given parameters in CO₂ supercritical extraction process is determined by taking the influence of process.Based on the analysis and comparison of the finite element analysis,particle swarm optimization and genetic algorithm on the CO₂ supercritical extraction platform developed,this paper chooses the principal component analysis?PCA?and response surface optimization?RSM?to establish the mathematical model of the supercritical extraction and the number of PCA-RSM.Then the common parameters in supercritical extraction process were determined,and the accuracy of the model was further verified by experimental data analysis.And the residual analysis of the experimental results was carried out.The optimum parameters of the supercritical extraction of Schisandra were obtained:temperature 38,pressure 40MPa,CO₂ flow 32L/h,and the supercritical extraction rate of18.51%.The control process of supercritical extraction is analyzed.The RBF-PID control algorithm is designed.The feasibility of the model is verified by Matlab.The comparison model with the traditional PID control model has good stability,small overshoot,fast adjustment speed and short adjustment time.Finally,the supercritical extraction process is designed from the hardware and software aspects.Measurement and control system.