Optimization of membrane-cryogenic hybrid propane recovery process: From molecular to process simulation

Abstract

Efficient volatile organic compounds (VOCs) recovery could not only prevent air pollution, but also achieve potential economic benefits. However, the traditional VOCs recovery technology faces the challenges of high energy consumption and low recovery rate. In this work, membrane materials and the membrane-cryogenic hybrid process for propane recovery was designed and optimized by using molecular and process simulation, respectively. In detail, 152 kinds of MOFs/PDMS and MOFs/PTMSP mixed matrix membranes were predicted through molecular simulation. PCN-48/PDMS and ZIF-12/PTMSP mixed matrix membranes (MMM) with high selectivity up to 56.6 and 31.9 and permeability up to 7.1 × 103 and 7.0 × 104 Barrer were obtained. The process simulation results indicated that optimized two-stage membrane-cryogenic (Mem-Cry-Mem) hybrid process could reduce operating expenditure from 1.28–2.24$/kg to 0.41–0.54$/kg and increase condensation temperature from −131∼ −110 °C to −105∼ −72 °C. Furthermore, the optimized Mem-Cry-Mem hybrid process could get high purity (>99% mol/mol) propane with energy consumption reduced by 48.5–73.8%. The hybrid process based on MMM presented significant techno-economic potential in the field of VOCs recovery.