热泵气扫式膜蒸馏装置再生除湿溶液性能研究

Study on the Regeneration Performance of Dehumidification Solution in a Heat Pump Sweeping Gas Membrane Distillation Device

除湿溶液对水蒸气有强烈吸收性,在空调、干燥等领域都有广泛应用,除湿溶液吸收一定量水蒸气后浓度下降,吸湿能力减弱,需要进行再生;针对沸腾蒸发再生方法需要配备真空设备、表面蒸发再生方法存在溶质损耗、电渗析法再生能耗较高等问题,设计了热泵结合气扫式膜蒸馏的除湿溶液再生装置,具有再生过程常压运行、除湿溶液无损耗、再生能耗低等特点;介绍了装置的流程和工作循环,给出了装置的特性方程,计算分析了装置关键影响因素如膜孔直径、除湿溶液浓度、除湿溶液温度、吹扫气流速对装置性能指标(单位膜面积再生速率、再生能耗比)的影响规律;建立热泵气扫式膜蒸馏实验装置对质量分数40%的溴化锂溶液在34.2℃进行了再生实验测试,表明单位膜面积再生速率可达0.55kg/(m^(2)·h),再生能耗比可达3.61kg/kWh,具有较好的应用优势。

The dehumidification solution has strong absorption to water vapor,and is widely used in drying,air conditioning and other fields.After absorbing a certain amount of water vapor,the concentration of dehumidifying solution decreases,and the hygroscopic ability is weakened,so regeneration is needed.Aiming at the problems that boiling evaporation regeneration method needs vacuum equipment,surface evaporation regeneration method has solute loss,and electrodialysis regeneration method has high energy consumption,a dehumidifying solution regeneration device with heat pump combined with sweeping gas membrane distillation was designed,which has the characteristics of running under normal pressure,no loss of solute,low energy consumption.Based on an introduction to process and working cycle of the device,the basic equations of the device are given.The influences of key factors such as membrane pore diameter,dehumidification solution concentration,dehumidification solution temperature and sweeping gas flow rate on device performance index(regeneration rate per unit membrane area,ratio of regeneration mass to energy consumption)were calculated and analyzed.The experimental device of heat pump sweeping gas membrane distillation was established to test the regeneration of 40%lithium bromide solution,the results showed that,when solution temperature is 34.2℃,the regeneration rate per unit membrane area could reach 0.55 kg/(m^(2)·h),and the ratio of regeneration mass to energy consumption could reach 3.61 kg/kWh,which has a significant application advantage.