Adsorption and desorption kinetics of hydrocarbons in FCC catalysts studied using a tapered element oscillating microbalance (TEOM). Part 2: numerical simulations

Modeling adsorption of CO2 on amine-functionalized mesoporous silica. 2: Kinetics and breakthrough curves

“…Previous studies showed that under such conditions, adsorption of nitrogen on TRI-PE-MCM-41 is negligible [9]. According to the analysis presented by Barrie et al [27], for gravimetric measurements in a microbalance, when a shallow layer of adsorbent is combined with a sufficiently high adsorbate flow rate, the influence of axial dispersion through the adsorbent layer does not affect significantly the experimental measurement. Furthermore, similarly to zero-length columns, it was proven that at low adsorbate concentration the operation could be considered isothermal despite the inherent release of heat associated with CO 2 adsorption.…”

Mass Transfer and Adsorption Equilibrium for Low Volatility Alkanes in BPL Activated Carbon

“…Except for one of the intermediate samples, the intracrystalline diffusivities showed a monotonic decrease with carbon number. Barrie et al 11 used a tapered element oscillating microbalance to measure uptake rates for n-hexane, n-heptane, n-octane, toluene, and p-xylene adsorbed on an ion-exchanged Y zeolite. By fitting their data, they found that intracrystalline diffusion is not the limiting factor affecting the overall rates of adsorption and desorption.…”

Diffusion in Fluid Catalytic Cracking Catalysts on Various Displacement Scales and Its Role in Catalytic Performance

“…The existence of transport limitations under conditions of fluid catalytic cracking has been discussed in a number of recent papers. − Probably the most common experimental approach which has been used to study transport limitations in FCC catalysts is based on monitoring the influence of the mean size of the zeolite crystals located in catalyst particles on catalytic conversion. − Provided that there are transport limitations related to intracrystalline diffusion, a decrease of the crystal size is expected to lead to an increase of the conversion rate and/or better selectivity due to faster molecular exchange between zeolite crystals and their surroundings. Depending on the experimental conditions and type of the reactant molecules used, both increased and unchanged conversion rates due to decrease of the crystal size have been observed. − In addition to this approach, modeling methods and the analytical treatment of experimental data based on the model introduced by Thiele have been applied for an elucidation of the role of molecular transport in the catalytic performance of FCC catalysts. − Despite all these efforts a detailed fundamental understanding of transport limitations in the FCC process has not been achieved. This situation is for the most part related to the lack of the direct information on diffusivities in FCC catalysts on various length scales.…”