Waste Gaseous Streams: From Environmental Issue to Source of Water by Using Membrane Condensers

In this work, the use of "membrane condensers" as new technology for the separation and recovery of evaporated "waste" water contained in the gaseous streams coming out from the chimneys of industrial plants is proposed. The proposed technology allows the condensation of this water by using hydrophobic membranes in a configuration where water condensation and recovery happens on one side of the membrane, whereas the dehydrated stream, passing through the membrane, is purged on the other side, under a temperature difference between the feed gas and the membrane condenser. Polyvinylidene fluoride microporous hydrophobic fibers were assembled in a module that operated for more than 150 days treating a saturated gaseous stream, while analyzing the effect of the main process variables such as temperature, feed flow rate, etc. Around 25% of the vapor contained in the feed was recovered as liquid under a temperature difference of 8°C and more than the 60% when the temperature decrease was of around 15°C. The "traditional" data analysis has been "helped" by an alternative analysis based on the use of two process intensification metrics, mass and energy intensities. This analysis provided additional indications to that obtained by the more conventional analysis, confirming the importance of including this new approach in the design of the membrane process.