Removal of thiophene from n-heptane/thiophene mixtures by spiral wound pervaporation module: Modelling, validation and influence of operating conditions

In recent years, pervaporation has been investigated rigorously for separation of thiophene and its derivatives from the fluid catalytic cracker (FCC) gasoline. Like other membrane-based processes, the scale up and commercialization of this process require the study of the separation performance at the membrane module scale. In this study, a suitable mathematical model is obtained to predict the performance of a spiral wound pervaporative module for the removal of thiophene from n-heptane/thiophene mixtures. The experiments were performed on a Polydimethylsiloxane (PDMS) based spiral wound module for a variety of operating conditions. The model predictions showed good agreement with the experiment results. Results indicate that the module performance may be improved with higher permeate pressures and the lower feed temperatures. However, this trend may not be universal and may be altered for some different feed systems or membranes, which shows the necessity to analyse every feed system and membrane material for determining the optimum operating conditions. Simulations also demonstrated that the variations in flow variables along the feed and permeate channels may also have profound effects on the module performances. Finally, the performance of a pervaporation process was simulated by using a number of spiral wound modules in series, which demonstrated that the pervaporation might successfully remove thiophene from FCC gasoline up to any desired limit.