Journal of Membrane Science, Vol.132, No.2, 229-233, 1997
A Hybrid of Vapor Permeation and Membrane-Based Absorption-Stripping for Voc Removal and Recovery from Gaseous Emissions
A hybrid process that combines a vapor permeation process with a recently developed membrane-based absorption and stripping process using an inert essentially nonvolatile absorbent oil is described here for a very high degree of removal of volatile organic compounds (VOCs) from vented gas streams. The combined and continuous process of this study uses the same utility, a vacuum pump, and achieves a very high level of VOC removal, for example, 99.57-99.97% from a N-2 feed stream containing 6,000 ppmv of methylene chloride. The performance is illustrated here using hollow fiber membrane modules of two kinds : microporous polypropylene hollow fibers having an ultrathin nonporous silicone coating used for vapor permeation first and then later for regenerating the VOC-loaded absorbent by VOC stripping via vacuum; microporous polypropylene hollow fibers without any nonporous coating for nondispersive absorption of VOCs from the waste gas stream.