Experimental investigations of a quasi-counter flow parallel-plates membrane contactor for air humidification

摘要

A cross-flow parallel-plates membrane-formed contactor is commonly used for air humidification.The cross-flow structure is convenient for duct sealings.To improve the performances of the contactor,a quasi-counter flow parallel-plates membrane contactor is proposed.In the contactor,the liquid water stream is separated from the air stream by membranes,which selectively permit the permeation of water vapor through them while prevent other gases and liquid water from permeating.Therefore the liquid water droplets,which are rather harmful for indoor air environment,can be completely prevented.The air and the water streams flow in a quasi-counter flow arrangement.In this paper,a test rig has been set up to study the performances of the contactor for air humidification.The air humidification experiment in the contactor is conducted under various inlet flow rates,temperature,humidity,and membrane parameters.The influences of these inlet operation conditions and membrane structures on the pressure drops,humidification effectiveness and total heat mass transfer coefficient are analyzed.It is found that the performances of membrane contactor increase with the increase of water flow rate and temperature.However,the key role of enhancing the transfer rate of water vapor is played by the water temperature.