Study On Sweeping Gas Membrane Distillation Device For Heat Sensitive Liquid

In the field of industrial production,many feed liquids that are sensitive to temperature need to be concentrated at low temperature;sweeping gas membrane distillation has the characteristics of high thermal efficiency and long service life.The structure and performance of the special air-sweep membrane distillation unit for heat-sensitive materials and liquids are systematically analyzed and experimentally studied.Three structural types of membrane distillation modules are proposed,namely,tubular membrane distillation module,plate and frame type membrane distillation module and diagram of cross-flow membrane modules;the principle,working process and performance characteristics of the three membrane distillation modules are respectively carried out.Introduced,and used Ansys software to model and simulate the three membrane distillation modules.The temperature field distribution of the device was obtained,which showed that the flow-through membrane distillation module has better comprehensive advantages.Established the physical of cross-flow model and mathematical model of the sweeping gas membrane distillation device dedicated to the heat-sensitive material liquid,and compiled the device performance simulation software to evaluate the device performance vary with the key parameters.The response surface method is used to optimize and analyze the key parameters of the device,and based on the requirements of different device water production rates,three optimization schemes are provided,which can provide guidance for device design.An experimental device for sweeping gas membrane distillation dedicated to heat-sensitive material liquid was made.The clarified orange juice was used as the material liquid.The concentration experiment was carried out under normal pressure and low temperature(17～22℃),and the performance changes of the device under variable operating conditions were obtained.Regular and optimized performance data for working conditions,when the temperature of feed liquid is 20.6℃,the flow rate of feed liquid is39g/s,the temperature of gas is 14.4℃,and the flow rate of gas is 3.5m/s,the membrane flux of the membrane distillation module is 0.13g/(m~2·s),the thermal efficiency of the membrane distillation module is 60%;the heat pump heating capacity is 183.16W,the heat pump heating coefficient is 4.57;the water production rate of the device is 0.049g/s,and the energy saving rate of the device is 3.01.The device has a good energy-saving effect;and the improvement direction of the experimental device is proposed,which can provide a reference for the industrial design and application of the device.