Mixed hydrophilic/hydrophobic fiber media for water-in-oil coalescence

摘要

Water-in-oil emulsions are commonly separated by fibrous coalescing filters. Wettability of the filter media has significant influence on filter performance. The wettability of the filter media depends on surface properties of fiber materials and porosity of filter medium. The wettability of the filter media is characterized using Modified Washburn's equation and expressed in terms of Lipophilic to Hydrophilic (L/H) ratio. In this work, filter media were prepared by mixing polypropylene microfibers and microglass fibers and also with polypropylene nanofibers and microglass fibers in different compositions. With variation in composition it is possible to achieve range of different L/H values. The effect of fiber size on wettability and filter performance is studied by addition of micro and nano fibers to microglass fiber media. Water and Viscor-1487 oil were used as test liquids for the wettability characterization. The filter media were tested in liquid-liquid coalescence experiments in which fine emulsions of water droplets were dispersed in the Viscor-1487 liquid. The polypropylene nanofiber added filter media showed significant improvement in separation efficiency over only glass fiber media but also showed increase in pressure drop. The polypropylene microfiber added filter media showed decrease in pressure drop as amount of polypropylene fibers increases.