Research On Heat Pump Membrane Distillation Device With Energy Recovery

Membrane distillation has good applicability such as handling high concentration liquid,separating liquid at low temperature and atmospheric pressure and so on.Heat pump membrane distillation can consume a small amount of electrical energy by heat pump to provide multiple heat and cold energy for membrane distillation.The cold and hot load shall be borne by energy recovery heat pump membrane distillation device by using energy recovery unit,which help to further reduce the energy consumption of membrane distillation process.Based on this,theoretical and experimental research on energy recovery heat pump membrane distillation device was carried out systematically in this paper.Structure of three processes of energy recovery heat pump membrane distillation device was given:external energy recovery type heat pump single effect membrane distillation device,external energy recovery type heat pump two-effect membrane distillation device,internal energy recovery type heat pump membrane distillation device.Their structures,working processes and the basic characteristics were analyzed,indicates that the internal energy recovery type heat pump membrane distillation device has good comprehensive advantages.For energy recovery heat pump membrane distillation device which filled with stationary condensate between the heat collector and the membrane,apple juice is used as the feed liquid,the physical model and mathematical model was established,the performance simulation software was compiled,the change regulations of performance indicators such as water production rate and energy saving rate were simulated and analyzed with the inner diameter of the hollow fiber,the number of the hollow fiber,membrane pore diameter,the membrane porosity,the hollow fiber length,flow rate of liquid,temperature of hot feed liquid into membrane distillation module and temperature of cold feed liquid into membrane distillation module.The results showed that he membrane porosity,the hollow fiber length,flow rate of liquid,temperature of hot feed liquid into membrane distillation module and temperature of cold feed liquid into membrane distillation module had significant effects on the water production rate and energy saving rate of the device.Under the guidance of the change rules of the water production rate and energy saving rate with the key parameters,an internal energy recovery type heat pump membrane distillation experiment device was developed.Taking 11.5°Brix apple juice as the experimental feed liquid,the feed liquid concentration rules were researched at normal pressure and 35℃.The fluctuation range of the main parameters and the performance index of the device under the specified parameters were obtained,which provided a good reference for the industrial application of the device.