(563c) Evaluation of the Improved Dynamic Linear Driving Force Model Using Kinetically Limited Breakthrough and Process Data

Effectively predicting the kinetically controlled mechanism in adsorption-based processes, such as N₂ PSA, using an ordinary Linear Driving Force (LDF) mass transfer model is a challenging task and needs accuracy in estimating the true driving force in the micropore domain. The standard LDF model assumes that the diffusion of the components (fast and slow) depends on the bulk gas phase partial pressure of each component outside the pore, which will erroneously overpredict the uptake of the slower diffusing components, and consequently, suppress the adsorbed phase loading of the faster diffusing components. To overcome the limitations of the standard LDF model, Adegunju et al. proposed the Kinetically Limited Linear Driving Force (KLLDF) [1] as an improvement. In our work, the KLLDF model was further improved to represent the mass transfer of O₂, N₂, and Ar on different types of Carbon Molecular Sieves (CMS). We added a temperature dependency term to the original KLLDF, which we validated through experiments. Since the model requires experimental determination of the mass transfer coefficient, an in-house apparatus was used to measure the kinetics through a series of controlled increases of pressure conducted at three different temperatures (8, 25, and 35^oC). The resulting data were fitted to extract the mass transfer parameters for the improved KLLDF, thereby capturing the loading and temperature dependencies. This improved model was then used for predicting kinetically limited adsorption breakthrough curves of O₂, N₂, and Ar on CMS as well as kinetically controlled N₂ PSA process performance at different operating conditions.