Heat Transfer Enhancement On Membrane Distillation Based Seawater Desalination Utilizing Temperature Difference Between Dry And Wet Wall

Energy crisis and the shortage of freshwater resources have become important factors which seriously restrict the development of economic and social. In this paper, temperature difference between dry and wet wall was proposed as a new energy resources, and combined with membrane distillation, it was applied to seawater desalination. The research has important sense to energy crisis and the shortage of freshwater resources.In this paper, a feasibility of membrane distillation based seawater desalination utilizing temperature difference between dry and wet wall was demonstrated, and an experiment device was set up using commercial hydrophobic polytetrafluoroethylene (PTFE) microfiltration flat membrane module. The influences of dry wall temperature, wet wall temperature and relative humidity on penetration flux was studied using the device. The experiment resulted in good effect,65g/(m2·h) was achieved as the maximum penetration flux.An enhancement on membrane distillation by solar energy was studied, which proved that solar energy could observably increase penetration flux. The maximum penetration flux rose to508g/(m2· h).A polluted process of multi-scale heat exchange surface in crystallized medium have been studied through optical electron microscopy observation, and a formula about the least effective scale and concentration was figure out.Through this research, people could have a deepen the understanding about temperature difference between dry and wet wall, a industrial application base of membrane distillation based seawater desalination was established, and the study on the least effective scale of multi-scale heat exchange surface was promoted.