Abstract
The focus of this article is on the analysis of transient breakthrough experiments measured in laboratory scale units. The scale up of such breakthrough data to industrial scale pressure swing adsorption (PSA) units requires simulations of the adsorption/desorption cycles in a sequence of multiple beds. This article provides a description of the simulation methodology that is essential for interpretation of laboratory scale data, and scaling up.A number of important conclusions are drawn from detailed analysis of large number of experimental breakthrough experiments, along with corresponding simulations.In the event that experimental breakthroughs are “sharp”, this is a strong indication of the absence of intra-crystalline diffusion influences. A consequence of intra-crystalline diffusion influences is that breakthrough characteristics attain distended characteristics. Commonly, but not always, distended breakthroughs result in diminished productivities of the desired product in mixture separation. In exceptional cases, intra-crystalline diffusion serves to complement and enhance the separations dictated by mixture equilibrium thermodynamics; such synergy manifests, for example, for 2MP/22DMB separations in MFI zeolite. For kinetically driven separations of C3H6/C3H8 mixtures using ZIF-8, and KAUST-7, both particle sizes and gas-particle contact times influence separations to a significant extent. The modelling of kinetically driven separations, requires thermodynamic coupling effects to be duly accounted for by use of the Maxwell-Stefan formulation for intra-crystalline diffusion.