Research Of Electro-hydraulic Proportional Control System Based On Seawater Desalination

There are 70.8% of the area of the earth is covered by water,but 97.5% of the water is seawater and can not be used directly,and in the remaining 2.5% of the fresh water,the amount of fresh water that can be used is only 0.26% of the total amount of t he earth's water.Therefore,developing desalination technology has become a top priority of modern society.The core technology of this paper is based on the principle of energy recovery.And the electro-hydraulic proportional control technology is applied in the system.To control sea water cylinder output pressure,the double-acting single piston rod hydraulic cylinder is applied to pressure closed-loop control,at the same time,the high pressure concentrated seawater not penetrate the reverse osmosis membrane is recovered.Because the sea of composition is very complex,so the problem of membrane pressure control will appear the time-varying parameters,external load disturbance and nonlinearity etc.Base on the process requirements the pressure before the membrane must be stable,so as to ensure the life of desalination equipment.Therefore,improve the performance of the system,to ensure the smooth membrane pressure has become the main goal of this study.Firstly,the structure and working principle of the hydraulic system of seawater desalination are analyzed and studied.The pressure sensor is used to detect the seawater pressure before the reverse osmosis membrane to control the displacement of the valve core of electro hydraulic proportional directional valve,so as to make the hydraulic cylinder output force is stable.Then,the mathematical modeling of each link in the hydraulic system is carried out,and the MATLAB software is used to analyze the system.Secondly,through the analysis of the system analysis found that the control system requires a controller to adjust the system.In this paper,PID controller and fuzzy PID controller are established according to the system output simulation curve and It is found that the fuzzy PID controller has better control effect.Then,in the actual application site,through the electrical system and hydraulic system installation and commissioning,the actual seawater output pressure data acquisition and analysis,indicating that this set of desalination system has a good control effect,ful y meet the actual process requirements.At last,summary the paper and research results,and puts forward the further work ideas and work prospects.