Membrane Recuperation Volatile Organic Compounds: Modeling of n-Octane Vapor Recovery by Polydecylmethylsiloxane

Comparative analysis of membrane materials was provided for the recovery of volatile organic compounds (VOCs) from vapor-gas mixtures generated during petroleum product loading operations. Mathematical modeling of membrane separation in a countercurrent mode was used to evaluate the effectiveness of two different membranes: polydecylmethylsiloxane (C10) and polydimethylsiloxane (PDMS), for recovery n-octane vapors, a model component limiting mass transfer during gasoline fraction recovery. Calculations were performed for a rail tank car loading and unloading process with a capacity of 830 m3/h and a target VOC recovery rate of 90%. It was found that the high selectivity of C10 with respect to n-octane vapor provides significant technological advantages, such as an increase in the concentration of n-octane in the permeate stream and a decrease in specific energy consumption. With a decrease in permeate pressure from 10 to 2 kPa, the required area of C10 membranes is shown to decrease by 6 times and for PDMS membranes by only 2.7 times. The costs of the membranes and energy consumption for VOC recovery from one railway tank car were estimated. The results obtained support the potential of using highly selective C10 membranes to create energy-efficient VOC recovery units for oil refining.