Analysis of high flux membranes for desalination in waste-heat driven vacuum membrane distillation plants: Experimental validation and techno-economic analysis

Vacuum membrane distillation is a promising technology for seawater desalination, as it enables high recovery ratios, with reasonable thermal and minimal electric consumption. Ceramic membranes can offer notable advantages over polymeric membranes, mainly due to their robust thermal and mechanical stability, yet they have limited representation in the literature. Accordingly, this work investigates ceramic membranes and their techno-economic performance for large scale desalination plants, with target recovery ratios above 85 %. First, a one-dimensional model for multilayered membranes was developed in MATLAB, validated against experimental data of water fluxes with different membrane materials, including ceramic ones, specifically collected within this work. This also enabled the fitting of the membrane characteristic parameters with the collected experimental data. With the aim of reducing the thermal consumption, a full-scale plant layout was defined with various stages in cascade and a sensible waste heat source at 90 °C. Results demonstrate that thermal consumption level in the 180–250 kWh/m3 range is possible, with average water fluxes around 20 kg/(m2·h). With reasonable assumptions on capital costs and plant availability, the levelized cost of water was found to be between 3 and $8/m3.