Study On The Measurement And Control System Of Heat Pump Membrane Distillation Device

Heat pump membrane distillation technology combines heat pump and membrane distillation technology.It has the characteristics of simple structure,low energy consumption,low temperature separation or concentration of heat sensitive liquid under normal pressure,and is suitable for food chemical,pharmaceutical and other industries.The combination of measurement and control technology and heat pump membrane distillation technology can effectively improve the control effect of the heat pump membrane distillation device,saving manpower and material resources.In this paper,the direct contact heat pump membrane distillation is used as the background,and its dynamic characteristics,control methods and control parameters are systematically studied.The classification,characteristics and performance parameters of heat pump membrane distillation are introduced.Typical measurement methods,control units,control methods and actuators are briefly described.The selected control unit is a PLC,the thermal resistance temperature sensor is a measuring component,and the electric valve is an actuator.The dynamic mathematical model of the heat pump membrane distillation unit was established.The dynamic simulation software of the device was compiled by VB.The calculation of key operating conditions parameters,membrane module performance,heat pump performance and overall performance of the device with the running time was calculated and analyzed.The influence of the different heat dissipation of the auxiliary cooler on the state parameters of the device is also calculated and analyzed.The results show that the regulation of the operating conditions of the device can be realized by adjusting the heat dissipation of the auxiliary cooler.The control strategy of the heat pump membrane distillation unit was analyzed.The function model of the heat dissipation of the auxiliary cooler was established and the parameters were optimized.The hardware and software design of the input unit,control unit and output unit of the measurement and control subsystem were carried out.The heat pump membrane distillation experimental device was developed and the measurement and control experiment was carried out.The complete working condition data of the experimental device from the start-up to the set operating state was obtained,which confirmed the feasibility of using the auxiliary cooling device to control the working condition of the auxiliary cooling device.The auxiliary cooler start time and heat dissipation function of the device.