Thermal performance of hydrophobic α-Al2O3 ceramic membrane for solar-thermal membrane coupling water desalination process

Abstract

A water desalination idea with high-efficiency was presented, which employed a vacuum tube type solar distiller to stuffy-thermal distillation and raw water preheating, and also utilized the hydrophobic α-Al2O3 ceramic membrane distillation (HCMD) modules and preheated raw water to membrane distillation (MD). In order to show the potential of HCMD to improve the photo-thermal conversion efficiency of the vacuum tube type solar distiller, this study explored the thermal performance and water desalination capacity of HCMD module driven by the recovered latent heat of the vacuum tube type solar distiller. The research results indicate that the membrane flux of HCMD had a significant positive exponential correlation with the raw water temperature (Tr). The convective heat transfer coefficient (h) of the hot side surface of hydrophobic α-Al2O3 ceramic membrane (HCM) was positively correlated with Tr and the concentration of raw water (C). The effects of Tr and cooling water temperature (Tc) on the thermal efficiency (η) of HCMD had an interaction. The theoretical maximum of η was close to 67.8%, and the variation range of η corresponding to the temperature range of preheated raw water by the solar distiller was 8.32–42.90%. The rejection rate of the HCM for all measured ions in the raw water was greater than 99.96%. This research was of great theoretical guiding significance for realizing the engineering application of the solar-thermal membrane coupling water desalination system.