Gas humidification performance of cellulose hollow fiber membranes

With deionized water as bore fluid and tap water as external coagulant, cellulose hollow fiber membranes (chfm) were prepared from a dope composed of cellulose/n-methylmorpholine-n-oxide (nmmo)/h2o using a wet spinning process. the prepared chfm showed dramatic dimension shrinkage after being naturally dried and the resulted dry chfm possessed a homogeneously dense structure that could ensure the water permeation stability during the humidification process. the swelling performance of chfm in water at different temperatures was tested and it was proven that increasing temperature would inhibit cellulose swelling in water. also its permeation rates in "water-swollen" state for gases such as h, and 0, were measured that could help to make sure only little gas leakage would happen during the humidification process. influence of water-gas pressure difference and water temperature on the water permeation flux of chfm was investigated. the results show that the water permeation flux of chfm increased with both the water-gas pressure difference and water temperature. with water-gas pressure difference at 0.2 mpa and water temperature at 80 degrees c, its water permeation flux could reach as high as 0.63 l/(m(2 .) h). the preliminary experiments were carried out to test its humidification ability for reacting gases of proton exchange membrane fuel cell (pemfc). with the self-made humidification module, the relative humidity of gases could be increased to over 90% under certain conditions. all these results show that the humidification ability of chfm is excellent,which means that it is suitable to be used in the humidification system for pemfc.