Application Progress of Separation Membrane on Membrane Liquid Desiccant Dehumidification

Due to the continuous improvement of people's requirements for indoor comfort, dehumidification technology has developed rapidly. Membrane-based liquid desiccant air dehumidification technology solves the problem of traditional liquid dehumidification with droplets, and has been widely used in recent years. The technology is coupled with the selectivity of membrane separation technology and the high absorption of liquid dehumidification. The high humidity gas is separated from the liquid desiccant through the selective membrane, and the water vapor molecules are driven by the differential pressure of water vapor on both sides of the membrane to complete the gas dehumidification process through the membrane. At present, researchers have done a lot of research works on the membrane materials and the configuration of membrane components in the membrane liquid dehumidifier. The membrane in the membrane-based liquid desiccant air dehumidification is a gas-liquid separation membrane, which can be divided into organic membrane, inorganic membrane, and organic-inorganic composite membrane according to the material. At present, the organic polymer membrane material is mostly used in the dehumidifier; and morphological structure can be divided into microporous film, dense film and composite film. The application of microporous membranes is restricted by the wetting phenomenon of membrane pores, and researchers have carried out hydrophobic modification studies. The dense film completely avoids the problem, an researcher has proposed an idea of an absorber unit, which provides ideas for the next research of the dense film. Compared with the previous two membrane structures, the composite membrane is more cost-effective. In recent years, a variety of composite membranes have been developed for gas dehumidification. The dehumidification separation membrane can be made into a flat type or a hollow fiber membrane type and formed into a flat membrane module and a hollow fiber membrane module. In order to reveal the heat and moisture transfer law in the membrane module, researchers have studied the fluid flow modes in the two membrane modules.A lot of research has been done on the mechanism of conjugate heat and mass transfer and the structure of the module, which is of great significance to the promotion and development of membrane-based liquid desiccant air dehumidification. The paper summarizes the latest research progress of separation membrane in membrane-based liquid desiccant air dehumidification, first introduces the working principle of membrane liquid dehumidifier, then summarizes the application of separation membrane materials in dehumidifier, mainly introduces the dehumidifier materials with different forms and structures, describes their characteristics and research progress, and then combines the research at home and abroad to different separation membrane groups in dehumidifier. The structure characteristics and the deve-lopment of heat and mass transfer of the components are summarized. Finally, the future research direction of the separation membrane in the membrane-based liquid desiccant air dehumidification technology is discussed. © 2020, Materials Review Magazine. All right reserved.