Conditions needed for satisfactory measurement of mass transfer coefficients, internal diffusivity and adsorption rate constants

Gangwal, S.K.; Hudgins, R. R.; Silveston, P. L.

doi:10.1002/cjce.5450560505

Cited by 12 publications

(4 citation statements)

References 46 publications

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“…The chromatographic method is practically useful to determine mass-transfer rates of each process in adsorbent beds and has been applied to both gas-and liquid-phase adsorption phenomena (Suzuki, 1990). A consideration was made for the advantages and disadvantages of the chromatographic method and for the conditions, under which accurate measurements of mass-transfer rates could be achieved (Awum et al, 1988;Ramachandran and Smith, 1978;Gangwal et al, 1978). Thermodynamic properties were also studied for adsorption and diffusion on surface and in micropores in gaseous systems (Chihara et al, 1978a).…”

Section: Aiche Journalmentioning

confidence: 99%

Adsorption characteristics of octadecylsilyl‐silica gel in gaseous systems

Miyabe

Suzuki

1993

AIChE Journal

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Adsorption rates and thermodynamic parameters were determined for the gasphase adsorption of n-alkanes and benzene derivatives on octadecylsilyl-silica gel ( ODs) by chromatographic measurement and moment analysis. Thermodynamic characteristics of adsorption phenomena on ODs were similar to those on the surface.The contribution of intraparticle diffusion to mass-transport resistance was dominant in the ODs column, and the role of surface diffusion was significant for the intraparticle diffusion. The values of the surface diffusion coefficient were of the order of lo-' cm2/s and could be estimated by assuming that the surface migration on ODs is a tracer diffusion of an adsorbate molecule in n-octadecane.

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Section: Aiche Journalmentioning

confidence: 99%

Adsorption characteristics of octadecylsilyl‐silica gel in gaseous systems

Miyabe

Suzuki

1993

AIChE Journal

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“…It is c~n v e n i e n t "~) to evaluate the coefficients of the Fourier f i t of the response rather than Equation ( 16), namely, (22) where is at least the number of unknown parameters in the model. Usually ni is 50 or greater.…”

Section: Fitting Techniquesmentioning

confidence: 99%

Reliability and limitations of pulse chromatography in evaluating properties of flow systems: 1. modelling and experimental considerations

1979

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Reproducibility of response characteristics and parameters derived therefrom, and adequacy of the Kubin-Kucera model for pulse chromatography were investigated experimentally using the physisorption of methane and ethane on silica gel. Reproducibility was found to be excellent, while the agreement of predicted and observed effects of velocity, particle size, temperature and bed length on model parameters confirmed the adequacy of the model. Agreement of the pore diffusivity and the adsorption equilibrium constant with values measured by other techniques provide further support for the model. Rearrangement of model terms shows that the rate coefficient for physisorption and the mass transfer coefficient cannot be measured using chromatography.

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“…and D,. Gangwal et al (1978) suggested that there is some controversy about evaluating the intraparticle diffusivity using the moment technique. They suggest that the resistances in series which consist of adsorption, mass transfer and intraparticle diffusion terms should be approximately of the same magnitude in order to obtain D, from the intercept of the second moment.…”

Section: Estimation Of Physical Parametersmentioning

confidence: 99%

Prediction of residual capacity in thin adsorbers

et al. 1983

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A simple reliable method to measure Residual Adsorption Capacity (RAC) of charcoal adsorbers on which a gas is physisorbed has been developed. The method consists of passing a pulse of weakly adsorbed gas(es) through the adsorption filter(s) and measuring the retention time. This retention time is then correlated to the residual adsorption capacity. In order to predict the retention time‐RAC relationship for filters with various configurations and bulk densities, this pulse test was mathematically modeled. The numerical solution of the model involved estimating the transport rate parameters, using existing correlations and the moment technique. A perturbation analysis indicated that the accuracy of the model is closely associated with the estimates of adsorption equilibrium constant and the intraparticle diffusion coefficient of the test gas. The model is shown to be accurate in predicting the RAC of an adsorber under dry and humid conditions from a limited data set.

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Conditions needed for satisfactory measurement of mass transfer coefficients, internal diffusivity and adsorption rate constants

Cited by 12 publications

References 46 publications

Adsorption characteristics of octadecylsilyl‐silica gel in gaseous systems

Adsorption characteristics of octadecylsilyl‐silica gel in gaseous systems

Reliability and limitations of pulse chromatography in evaluating properties of flow systems: 1. modelling and experimental considerations

Prediction of residual capacity in thin adsorbers

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