1990 Volume 16 Issue 6 Pages 1203-1209
The heat and mass balance of membrane distillation using PTFE porous membrane were studied using 3.4wt% NaCl solution as feed liquid. Parameters such as temperature and flow rate of feed and cooling water were varied and heat and mass transfer characteristics were studied by measuring the permeate rate and the temperature difference between feed and cooling water.
The results are summarized as follows. In the membrane distillation system, heat and mass transfer mechanisms changed when the gap was below 5 mm or over 10 mm. For a gap below 5 mm, heat transfer was controlled by thermal conduction and mass transfer was controlled by diffusion. For a gap over 10 mm, the heat and mass transfer were controlled by free convection. These transfer rates were expressed using thermal conduction, diffusion and free convection equations. Numerical studies were performed and good correlations were confirmed between numerical and experimental results.
