HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Propylene-propane separation is one of the most difficult and demanding energetic operation currently practiced using cryogenic distillation. Extensive studies on various alternatives showed that cyclic adsorption processes, and particularly pressure swing adsorption (PSA), might be an option to replace the traditional distillation. In spite of the promising results of the PSA process, much attention is currently being paid to the simulated moving bed technology (SMB) for gas-phase separations. The ingenious principle of this process is based on the choice of an adequate adsorbentdesorbent couple. Thus, in the present work 1-butene has been studied as an interesting desorbent to displace adsorbed propylene-propane mixture on 13X zeolite. The measurements of pure 1-butene adsorption isotherms over 13X zeolite were performed with a gravimetric experimental device for pressure ranging from 0 to 110 kPa and at temperature of 333, 353, 373, and 393 K. The experimental adsorption data were correlated using Toth model. The heat of adsorption at zero coverage and the maximum loading capacity of 1-butene were found to be 54.4 kJ/mol and 2.10 mol/ kg, respectively. The adsorption and desorption of 1-butene on 13X zeolite packed on a fixed bed initially saturated either by a propane-propylene mixture or a pure C 3 hydrocarbon has been studied. The performance of 1-butene has been compared with isobutane that was previously proposed to be a highly effective desorbent for C 3 H 6 / C 3 H 8 separation. A model based on a double LDF approximation for the mass transfer combined to a heterogeneous energy balance taking into account a variable velocity of the gaseous bulk phase, has been used to describe the breakthrough curves obtained experimentally at 373 K and 110 kPa.
The design of a simulated moving bed (SMB) process relies on valid thermodynamic predictions of multicomponent adsorption built up from accurate binary adsorption equilibrium data. Experimental adsorption equilibria of binary mixtures constituted by propane, propylene, isobutane and 1-butene on 13X zeolite were determined using breakthrough experiments at 373 K and 150 kPa. In addition, these binary adsorption experiments allow to confirm the choice of isobutane as an interesting desorbent for the separation of propane-propylene by SMB, since it has an intermediate selectivity between the two species to separate. Various prediction models are available in the literature but only a few of them have both physical and thermodynamical consistency. The ideal adsorbed solution theory (IAST), the thermodynamically consistent extended Toth model (TCET), and the physically-consistent extended Toth isotherm (PCET) were used to predict binary adsorption equilibria from pure component adsorption isotherms
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.