Experimental and theoretical study of a lab scale permeate gap membrane distillation setup for desalination

摘要

Membrane distillation (MD) as a novel thermally-driven process with moderate operating temperatures is a known effective technology for salt-water desalination. In this research, a lab scale plate-and-frame permeate gap membrane distillation (PGMD) module with internal heat recovery characteristic is designed. The developed PGMD module performance is experimentally investigated for fresh and saline water feed in terms of permeate water flux rate, specific thermal energy consumption (STEC) and gained output ratio (GOR). The experimental results show that for a feed sample with 130 (g/kg: ppt) concentration (nearly four times seawater salinity), increasing the feed flow rate from approximately 0.4 to 1 L/min, led to increasing the distillate flux from 3 to 5 kg/m(2) h. However, increasing the feed flow rate in this range also led to approximately 40% increase in the STEC of the system. Furthermore, a single node theoretical model based on the PGMD module configuration is developed and the modelling results validated with experimental values at different feed water flow rate and salinity.