Transport membrane condenser for water and heat recovery from gaseous streams: performance evaluation

Using a tubular ceramic membrane as the transport membrane condenser for simultaneous water and heat recovery from gaseous streams is experimentally investigated in the current study. The effects of several important operational parameters (e.g. gas flow rate, coolant flow rate, transmembrane pressure and inlet gas temperature) on the process performance in terms of mass and heat transfer across the membrane are systematically studied. It is found that mass and heat transfer rates can be enhanced by increasing the gas flow rate, coolant water flow rate and the temperature of the inlet gas stream. To improve the water and heat recovery, a low gas flow rate but a high coolant flow rate should be maintained. Increasing the transmembrane pressure difference decreases the mass and heat transfer mainly due to the reduced inlet gas humidity, enthalpy and flow rate. However, water and heat recovery does not change significantly with the change in transmembrane pressure. 20-60% water recovery and 33-85% heat recovery are achievable when using cold water as the coolant. The mass transfer mechanism in membrane condensation is complex and needs further exploration. These findings offer significant implications in using transport membrane condensers for water and heat recovery from gas streams with high moisture.