Modelling Study of Palladium Membrane Reactor Performance during Methan Steam Reforming using CFD Method

摘要

The main aim of this study is the investigation of dense palladium membrane reactor (MR) performance during methane steam reforming (MSR) reaction using computational fluid dynamic (CFD). To this purpose, a two-dimensional isothermal CFD model was developed and its validation was realized by comparing the theoretical results with our experimental data achieved in ITM of Italy. In this work, the CFD model was presented by COMSOL- Multiphysics software version 5. The reaction rate expressions and kinetics parameters were used from literatures. According to validation results, a good agreement between modeling results and experimental data was found. After model validation, the effect of the some important operating parameters (temperature and pressure) on the performance of palladium MR was studied in terms of methane conversion and hydrogen recovery. The CFD model presented velocity and pressure profiles in both side of MR and also molar fraction of different species in permeate and retentate streams. The modeling results showed that the palladium MR presents comparable performance with respect to traditional reactor (TR) in terms of the methane conversion, especially, at lower temperatures and higher pressures. In fact, CFD results indicated that palladium MR performance was improved by increasing the reaction pressure, while this parameter had negative effect on the TR performance. This result related to increasing the hydrogen permeance through the palladium membrane by enhancement of pressure gradient. Indeed, this shift effect can provide a higher methane conversion in lower temperatures in the palladium MR. In particular, 99% methane conversion and 43% hydrogen recovery was achieved at 500°C and 1.5 atm.