Modeling of a differential volumetric system for high pressure gas adsorption

The volumetric system is a widely used experimental method for gas adsorption equilibrium measurements and for the determination of adsorption kinetics. A predictive model was developed in the gPROMS ProcessBuilder platform. Equations for mass and energy balance were implemented firstly for the description of a single-branch volumetric apparatus, and then for a differential (double-branched) system. The model was built starting from the simplest case (Isothermal and ideal gas behaviour) and subsequentially its complexity was increased in order to have a system which is able of describing an adsorption process in any operative conditions (non-isothermal system, non-linear equilibrium, real gas behaviour). The validation of the model was made through the assumption that all the complex systems must collapsed to the simplest one through the adjustment of the different parameters. In certain cases, the validation was done comparing the results obtained in the simulation with the one got from analytical solutions developed by other authors. In general, at the end of each section, a case study was analysed in order to underline what are the factors that can affect the kinetic of the process, providing also possible solution which can minimize these effects, that if not taken into account can lead to an incorrect interpretation of the data.