Removal and Recovery of Volatile Organic Compounds by Membrane and Condensation Process

摘要

Volatile organic compounds(VOC's) generated from many industries are causing air pollution and aggravating the atmosphere of plant workers. Amount of VOC's produced reaches 30,810,000 ton/year and it is expected to continuously grow. Some of the VOC's are quite expensive and they have to be recovered for reuse. Several methods to remove and recover VOC's such as adsorption, absorption, catalytic combustion, pressurized condensation, and membrane separation. Each process has its own advantages and limitations. In this work we developed the hybrid process of membrane and condensation, which can overcome the problems encountered with appreciable performances. VOC stream was pressurized and cooled, and some part of the VOC was condensed. The remaining VOC's in the stream was introduced into the membrane module and VOC content in the retentate stream was reduced to the level for vent. Organophilic composite membranes were prepared by PDMS coating and plasma polymerization processes, which can concentrate the permeate stream recycled to the process. VOC removal efficiency reached upto 90 % by this process. Membrane preparation conditions were investigated and optimized for the enhancement of the membrane performances.