Modeling, Simulation, and Pilot Prediction of a Facilitated-Transport Membrane with Two-phase Permeate Flow for Olefin–Paraffin Separation

Abstract

We present a mathematical model and numerical scheme tailored to our Optiperm Propane–Propylene spiral-wound membrane. To use simulation for accurate scale-up designs, we model a diverse array of physical phenomena. These include nonideal, temperature-dependent descriptions of flux and humidification induced by liquid water flow on the permeate side of the membrane. To enable monitoring of membrane performance with parameter optimization, we approximate the change in direction along the permeate side as a combination of cross and counter-current flow regions, as well as a finite difference technique implemented in the C programming language. As an application of the computational methodology, we perform a series of experiments and use numerical optimization to identify membrane transport parameters. We then perform simulations with these optimal properties to predict the purities and stage cuts of a membrane installed at Braskem. With absolute differences in stage cut and purity of 2.9 ± 2.8 and 1.4 ± 0.8%, respectively (and smaller in commercially relevant regimes), simulations enable accurate design and reduce risk in the transition from lab to commercialization.