Modeling the Adsorption Step during Hydrogen Purification in Gas Treatment Application

Abstract

Abstract The present work is interested in modeling the adsorption step for the process of Pressure Swing Adsorption (PSA) for hydrogen purification. This work aims at modeling the adsorption of one or more compounds in a mixture at different pressures ranging from 8 to 20 bars at ambient temperature. The flow was presented by the piston model with an axial dispersion. The equilibrium isotherm was expressed by the Langmuir model for the mono-component adsorption and the model of Langmuir extended for the multi-component adsorption. Moreover, two models of kinetic transfer between the gaseous and solid phases were considered, the first-order model based on the approximation of the Linear Driving Force (LDF) and a sophisticated model which is the Surface Diffusion model (SD). As a first step, the CH4/H2 mixture adsorption on activated carbon was studied. In a second step, the adsorption of CH4/CO2/H2 on activated carbon and of CH4/N2/H2 on a 5A° molecular sieve was studied taking into consideration an interaction parameter for the extended Langmuir model. The simulation results obtained after the resolution of the equations of the model in a developed program, compared with the experimental results from previous works, show a rather satisfactory agreement on the level of stoichiometric time and kinetic mass transfer.