Fixed Bed Adsorption of CO₂, CH₄, and N₂ and Their Mixtures in Potassium-Exchanged Binder-Free Beads of Y Zeolite

Abstract

The adsorption of carbon dioxide (CO 2 ), methane (CH 4 ), and nitrogen (N 2 ) has been studied on potassium-exchanged (95%) binder-free beads of Y zeolite through single, binary, and ternary fixed bed breakthrough experiments, covering the temperature range between 313 and 423 K and a pressure of up to 350 kPa. At 313 K and 350 kPa, the single-component data obtained showed that the amounts adsorbed of CO 2 , CH 4 , and N 2 are around 6.42, 1.45, and 0.671 mol kg −1 , respectively. The binary experiments CO 2 / N 2 carried out under typical post-combustion conditions show a selectivity of CO 2 over N 2 around 104. The ternary experiments resulted in the selectivities of CO 2 over CH 4 and N 2 around 19 and 45, respectively. The adsorption equilibrium data have been modeled by the dual-site Langmuir model, and the breakthrough experiments were numerically simulated with a suitable dynamic fixed bed adsorption model. The model predicts with good accuracy the systematic behavior of all breakthrough experiments. The results shown in the present work prove that the potassium-exchanged binder-free beads of Y zeolite enhance the amount adsorbed of CO 2 at low partial pressure over other alkali metal-exchanged faujasites and efficiently separate it from binary (CO 2 /N 2 ) and ternary (CO 2 /CH 4 /N 2 ) mixtures by fixed bed adsorption.

Equilibrium and Kinetic Insights into the Comprehensive Investigation of CO2, CH4, and N2 Adsorption on Cation-Exchanged X and Y Faujasite Zeolites

“…Micropore (intracrystalline) or macropore diffusion (intercrystalline) may control the mass transfer mechanism within adsorbent particles. Previous research has revealed that adsorption on the zeolites was controlled by both macropore- and micropore-diffusion mechanisms. , …”

“…Previous research has revealed that adsorption on the zeolites was controlled by both macroporeand micropore-diffusion mechanisms. 33,34 This way, gravimetric and volumetric techniques have mainly been used for gas storage and separation studies. Gravimetric techniques have some shortcomings, such as considering the buoyancy effect on the volume of the system, the incapability of investigating multicomponent adsorption, and the high cost of the unit.…”

Mg-Exchanged Gismondine for Superior CO2/N2 and CO2/CH4 Separations

“…However, under industrially relevant conditions, the CO 2 separation using physical adsorbents such as zeolites is performed in a fixed bed configuration under dynamic conditions where the separation performance of adsorbents is dictated by the capacity, selectivity, and cyclability. Hence, despite being scarcely reported for novel laboratory-scale adsorbents, − breakthrough measurements are mandatory to properly understand and evaluate the practical application of zeolitic adsorbents.…”

Green Hydrogen Recovery from Natural Gas Grids by Vacuum Pressure Swing Adsorption

“…Adsorption processes are widely acknowledged as economically efficient and appealing alternatives for addressing various industrial challenges, including but not limited to postcombustion CO 2 capture, − H 2 purification from steam methane reforming (SMR), − medical O 2 concentrator, − biogas upgrading, − and separation of straight-chain hydrocarbons from the branched chain. − Consequently, pressure swing adsorption (PSA), which is a cyclic process that uses pressure driven to perform bulk separation, is commonly used for H 2 purification from SMR. , The typical SMR off-gas is a mixture of H 2 /CH 4 /CO/CO 2 with a composition of 76/3/4/17%, respectively. From this composition, the conventional PSA can achieve purities of up to 99.9999% with high recoveries of around 96% .…”