Modelling and sensitivity analysis of a nanocomposite MFI-alumina based extractor-type zeolite catalytic membrane reactor for m-Xylene isomerization over Pt-HZSM-5 catalyst

In this paper, a report on modelling and sensitivity studies of a laboratory-scale extractor type catalytic membrane reactor having a nanocomposite MFI-alumina membrane tube as separation unit is presented. Meta-xylene isomerization over Pt-HZSM-5 catalyst was conducted in the reactor and the results compared with model output. Sensitivity of the model to changes in certain design parameters (membrane thickness, membrane porosity, membrane tortuosity and reactor size) was evaluated for in-depth understanding of the fundamental behaviour of the system during m-Xylene isomerization. The model output deviated from the experimental results with percentage errors of 17%, 29%, 0.05% and 19.5% for p-Xylene yield in combined mode, p-Xylene selectivity in combined mode, p-Xylene selectivity in permeate-only mode and m-Xylene conversion, respectively. Despite the discrepancy between the experimental results and the model output due to the to quality of data employed in the simulation and assumptions adopted for model simplification, the model could explain the behaviour of e-ZCMR during m-Xylene isomerization over Pt-HZSM-5 catalyst and also adaptable to e-ZCMRs of different configurations such as hollow fibre MFI-alumina membrane-based e-ZCMRs. However, acquisition of accurate kinetics and diffusion data through experimentation is essential to improve on the model. As expected, the sensitivity analysis revealed that membrane porosity, membrane tortuosity, membrane effective thickness and reactor size play a significant role on the performance of the e-ZCMR during the isomerization. Although, this model is of a preliminary nature, still it provides useful assistance in understanding the fundamental behaviour of e-ZCMR during m-Xylene isomerization and offers a platform upon which further modelling studies on m-Xylene isomerization in e-ZCMR can be built.