| Volatile organic compounds (VOCs) produce a large amount of waste emissions when the processing plants load, unload the oil onto the tanks, fuel tankers and oil tankers. The recovery of Volatile organic compounds has been under scrutiny. However, most existing techniques for organic vapor emissions control have so far proved to be unsatisfactory. Membrane technology which has high efficiency, economy, simple operation and no secondary pollution is expected to provide an alternative to the recovery of VOCs. In this study, the preparation of hollow fiber composite membranes, gas membrane separation and the mathematic model of mass transfer were investigated.Firstly, the hollow fiber composite membranes were prepared by dip-coating method with 4 kinds of hollow fibers as the substrate layer, and 3 kinds of silicone rubbers as the coating layer material. The effects of some factors, which include the silicone rubber, catalyst and cross-linker concentration of composite membrane on gas separation performance were discussed. The heating treatment was applied to enhance the separation performance of some membrane, which shows that the physical structure of base membranes has effect on the separation performance of composite membrane. The suitable conditions for heating treatment and preparing the composite membrane were found, and the composite membrane of RTV-107/PVDF got the best performance with the base membrane heating treatment under 393.2K and 12 minute. The structure and properties of silicone rubber, base membrane and hollow fiber composite membranes were analyzed by SEM, IR and XPS methods.Secondly, the effects of feed pressure, feed flow rate, feed concentration, permeate pressure and operating temperature on the gas separation performance also investigated. The permeabilities of n-hexane and n-heptane were 1.4×10-7,1.5×10-7 mol/(m2·s·Pa) respectively and the separation factors of n-hexane/nitrogen and n-heptane/nitrogen could be 90,474 respectively.The third, filled-type composite membrane was prepared. The effect of species and amount of filling agents on the gas separation performance was also discussed. The permeabilitiy of n-heptane and the separation factor of n-heptane/nitrogen were improved when the composite membrane was filled with filling agents. Otherwise, the mechanical performance of silicone rubber filled with suitable fillings was increased. Then a two-layer model based on DGM model was presented to describe the influence of the porous support layer of the composite membrane on the gas separation performance. The effect of the base membrane structure parameters such as effective porosityε/τ, morphological parameter K0 and the thickness of coating on gas separation properties were also discussed.Lastly, for RTV-107/PVDF hollow fiber membrane, a countercurrent-flow design model was established which can describe VOCs/N2 separation process. This mathematical model was based on the gas linear flow rate and could be applied in more gas separation processes, which was better than the model in most references. The simulation using the model is performed by changing the operating conditions and the optimum operating factors and the required membrane area are investigated. Then the design proposal of this technique for industrial application was brought forward.
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