Diffusion mechanism of CO2 in 13X zeolite beads

Hu, Xin‐Sheng; Mangano, Enzo; Friedrich, Daniel; Ahn, Hyungwoong; Brandani, Stefano

doi:10.1007/s10450-013-9554-z

Cited by 92 publications

(91 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By drawing the representative uptake curves at logarithmic scale (Fig. 10), the change of the controlling mechanism for successive runs can be observed [5,26]. Also the behavior of the runs were similar at the regeneration temperature of 120 C and 150 C (Fig.…”

Section: Adsorption Equilibrium Of Zeolite 13x-water Pairmentioning

confidence: 99%

Effect of regeneration temperature on adsorption equilibria and mass diffusivity of zeolite 13x-water pair

Sayılgan

Mobedi

Ülkü

2016

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

a b s t r a c tThe adsorption equilibrium and mass diffusivity of zeolite 13X-water pair for different adsorption and regeneration temperatures were determined by a homemade volumetric system. The isotherms of the zeolite 13X-water pair were obtained by collecting pressure versus time data and applying ideal gas law. The effective diffusivity of the pair was calculated by using long term analytical solution of mass diffusivity based on Fick's law.The experimental study showed that the adsorption capacity of zeolite 13X-water pair was 23% (kg/ kg), 21% (kg/kg) and 19% (kg/kg) when the adsorption temperature was 35, 45 and 60 C respectively for the desorption temperature of 90 C. Furthermore, the adsorption capacity increased from 22% (kg/kg) to 24% (kg/kg) when the desorption temperature was increased from 90 C to 150 C. It was observed that the present adsorption equilibrium results were compatible with the reported results in the literature.The mass diffusivity of the pair was found in the range of 4 Â 10 À9 e6 Â 10 À8 m 2 /s for the long time period when the initial adsorptive pressure was 2000 Pa. The effective mass diffusivity depends on concentration and it was decreased with increasing adsorbate concentration.

show abstract

Section: Adsorption Equilibrium Of Zeolite 13x-water Pairmentioning

confidence: 99%

Effect of regeneration temperature on adsorption equilibria and mass diffusivity of zeolite 13x-water pair

Sayılgan

Mobedi

Ülkü

2016

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

show abstract

“…(4) is not guaranteed in general. Therefore, to obtain (ha/q s C s ) and b as a first step, the kinetic model of an entirely heat-controlled system was presented in the asymptotic form of kinetic models as follows: (Hu et al 2014;Lee and Ruthven 1979;Ruthven et al 1980)…”

Section: Theorymentioning

confidence: 99%

“…Zeolite pellets consist of micropores in zeolite crystal, macropores among zeolite crystals and binder. Therefore, studies have analyzed the contributions of macropores and micropores in the rate-determining step of N 2 , CH 4 and CO 2 in zeolite 4A, 5A, CaX and 13X pellets (Ahn et al 2002(Ahn et al , 2004Silva et al 2012;Hu et al 2014). In a carbon molecular sieve, controlled micropores significantly affect the adsorption kinetics, and the kinetic difference among adsorbates strongly depends on molecular size and adsorption affinity (Bae and Lee 2005;Giesy and LeVan 2013;Yang et al 2014).…”

mentioning

confidence: 99%

Adsorption kinetics of CO2, CO, N2 and CH4 on zeolite LiX pellet and activated carbon granule

Park

et al. 2015

Adsorption

View full text Add to dashboard Cite

The adsorption uptake curves of CO 2 , CO, N 2 and CH 4 on zeolite LiX and activated carbon were measured using a volumetric method at 293, 308 and 323 K and pressure up to 100 kPa. The experimental uptake curves were correlated with a non-isothermal kinetic model because the adsorption kinetics was controlled by heat generation and transfer, and an isothermal model showed large deviation from experimental uptake. The adsorption rates of the gases on zeolite LiX and activated carbon were affected by the isosteric heat of adsorption, heat transfer rate and adsorption affinity. At the same pressure and temperature, the sequence of effective diffusion time constants was CO 2 ( CO \ N 2 \ CH 4 for zeolite LiX and CO 2 ( CH 4 B N 2 \ CO for activated carbon. The adsorption rate of CO showed the largest difference between the two adsorbents. Effective diffusion time constants (D/R 2 ) for all cases were provided, which depended on pressure and temperature.Keywords Activated carbon Á Zeolite LiX Á Adsorption kinetics Á Heat of adsorption Á Non-isothermal model List of symbols a External surface area divided by the volume of the adsorbent (m -1 ) c p Concentration in the particle (mol kg -1 ) C s Heat capacity of the sample (J g -1 K -1 ) D/R 2 Effective diffusion time constant (s -1 ) D Diffusivity (m 2 s -1 ) D c /r c Micropore diffusion time constant (s -1 ) D p /R p Effective macropore diffusion time constant (s -1 ) hOverall heat transfer coefficient (J m -1 s -1 K -1 ) K Henry constant (-) P Pressure (kPa) Q Adsorbed amount (mol kg -1 ) Q st Isosteric heat of adsorption (kJ mol -1 ) R Ideal gas constant (J mol -1 K -1 ) R 2 Coefficient of determination (R 2 ) (-) T Time (s) T Temperature (K) V g Volume occupied by the gas (m 3 ) V s Volume occupied by the adsorbent (m 3 ) a Dimensionless parameter defined by nonisothermal model (-) bDimensionless parameter defined by nonisothermal model (-) q s Density of the adsorbent (g m -3 )

show abstract

“…39,40 In order to minimise the pressure drop across the column, the samples were made as binderless pellet fragments ca. To enable analysis of the results, blank runs were also carried out.…”

Section: Preparation and Characterisation Of Dehydrated Li-and Mli-rmentioning

confidence: 99%

Cation Control of Molecular Sieving by Flexible Li-Containing Zeolite Rho

et al. 2016

Self Cite

View full text Add to dashboard Cite

The adsorption of CO 2 on zeolite Li-Rho (unit cell composition Li 9.8 Al 9.8 Si 38.2 O 96 ) has been investigated by the measurement of adsorption isotherms (273 -300 K), breakthrough curves with a CO 2 /CH 4 /He mixture (308 K) and in situ synchrotron X-ray powder diffraction in CO 2 (298 K). The Rho framework distorts when in the Li-form to give a shape selective adsorbent for CO 2 over CH 4 , although breakthrough curves reveal diffusional limitations. In situ synchrotron powder XRD follows the expansion of the Li-Rho unit cell upon adsorption, which remains single phase to a CO 2 pressure of ca. 0.6 bar. Partial cation exchange of Li-2 Rho by Na + or Cs + gives two series of M,Li-Rho zeolites (M = Na, Cs). Where the occupancy of window sites (8R, D8R) between lta cages is less than 50%, hysteresis is not observed in CO 2 isotherms at 298 K. For Cs 1.8 Li 8 -Rho, which has a larger unit cell and a wider window than zeolite Li-Rho due to the presence of large Cs + cations in double 8-ring sites, breakthrough curves indicate faster CO 2 diffusion without significant loss of selectivity. We propose this control of adsorption kinetics of the flexible zeolite Rho via modification of cation content as a mechanism for cation controlled molecular sieving.

show abstract

Diffusion mechanism of CO2 in 13X zeolite beads

Cited by 92 publications

References 39 publications

Effect of regeneration temperature on adsorption equilibria and mass diffusivity of zeolite 13x-water pair

Effect of regeneration temperature on adsorption equilibria and mass diffusivity of zeolite 13x-water pair

Adsorption kinetics of CO2, CO, N2 and CH4 on zeolite LiX pellet and activated carbon granule

Cation Control of Molecular Sieving by Flexible Li-Containing Zeolite Rho

Contact Info

Product

Resources

About