Single‐pellet cell for the measurement of intraparticle diffusion and convection

Lu, Z. P.; Loureiro, José M.; Rodrigues, Alírio E.

doi:10.1002/aic.690380310

Cited by 9 publications

(3 citation statements)

References 22 publications

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“…This technique was later modified to investigate diffusion in porous solids having a bidispersed pore size distribution (Dogu and Ercan, 1983) to determine the rate parameters for noncatalytic fluid-solid reactions (Dogu et al, 1986) and to analyze viscous flow and diffusion in porous solids (Dogu et al, 1989;Lu et al, 1992). In more recent studies, the technique was extended to sorption and migration of volatile organic pollutants in soil (Dogu et al, 1993;Cabbar et al, 1994).…”

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confidence: 99%

One‐sided single‐pellet technique for adsorption and intraparticle diffusion

et al. 1996

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The one-sided single-pellet dynamic technique introduced in this article is shown to be a very effective and simple method for the analysis of adsorption and difision in porous solids. Moment expressions are presented for reversible and irreversible adsorption processes. Since the adsorption equilibrium constant is the only unknown parameter in the first moment expression, this parameter can be evaluated from a single set of pulse-response experiments. This technique to evaluate the adsorption equilibrium constant is illustrated using ethylbromide as tracer. It is also shown that for a very strongly adsorbing tracer, such as 1,d-dichloroethane in soil, modiJied moment expressions derived with a semiinfinite boundary condition are necessary unless a criterion developed in this work is satisfied.

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One‐sided single‐pellet technique for adsorption and intraparticle diffusion

et al. 1996

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“…The single-pellet moment technique has also been used for the measurement of adsorption rate and equilibrium constants (Dozu and Smith, 1976; DoEu and Ercan, 1983), as well as reaction rate parameters (Do& 1984; Do& et al, 1986). Recently, the technique has been modified for the measurement of thermal conductivity of a porous solid (DoHu et al, 1989a(DoHu et al, , 1991 and permeability (Dogu et al, 1989b;Lu et al, 1992). Boundary conditions used in the single-pellet moment theory were discussed by Burghardt and Smith (1979) and more recently by Lu et al (1992).…”

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confidence: 99%

“…Recently, the technique has been modified for the measurement of thermal conductivity of a porous solid (DoHu et al, 1989a(DoHu et al, , 1991 and permeability (Dogu et al, 1989b;Lu et al, 1992). Boundary conditions used in the single-pellet moment theory were discussed by Burghardt and Smith (1979) and more recently by Lu et al (1992). In the analysis of Lu et al, the validity region of the simplified boundary conditions used in most of the published literature Correspondence concerning this work should be addressed to T. Dogu.…”

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Single‐pellet technique for irreversible and reversible adsorption in soil

1993

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The dynamic version of the Wicke-Kallenbach diffusion cell has been used extensively for the evaluation of effective diffusion coefficients (Suzuki and Smith, 1972; Dogu and Smith, 1975; Furusawaet al., 1976;Moffatt, 1978; Baiker et ai., 1982;Wang and Smith, 1983; DoZU et al., 1987). The single-pellet moment technique has also been used for the measurement of adsorption rate and equilibrium constants (Dozu and Smith, 1976; DoEu and Ercan, 1983), as well as reaction rate parameters (Do& 1984; Do& et al., 1986). Recently, the technique has been modified for the measurement of thermal conductivity of a porous solid (DoHu et al., 1989a(DoHu et al., , 1991 and permeability (Dogu et al., 1989b;Lu et al., 1992). Boundary conditions used in the single-pellet moment theory were discussed by Burghardt and Smith (1979) and more recently by Lu et al. (1992). In the analysis of Lu et al., the validity region of the simplified boundary conditions used in most of the published literature Correspondence concerning this work should be addressed to T. Dogu.

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An approach for the optimization of transient diffusion cell measurements

Sun¹,

Magalhães

Costa

2001

Can J Chem Eng

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arameter estimation from experimental data subject to interference of secondary phenomena may be troublesome. A correct design of P the apparatus employed may be decisive for the quality of the measurements. A strategy for correctly identifying the optimal sets of design variables is therefore needed in order to minimize such problems. The present work elaborates on the issue of diffusion measurements, using a diffusion cell setup, being affected by film mass transfer resistance, and how a methodical theoretical analysis can be performed in order to clarify the proper design procedures. Despite the fact that some of the conclusions obtained might seem intuitive, the emphasis should be placed on the systematic approach employed, which can be generalized to problems of an altogether different nature.The transient diffusion cell method (also commonly known as transient Wicke-Kallenbach experiment) is one of the most widely used techniques for determining effective diffusivities of gases in porous solids (Haynes, 1988;Karger and Ruthven, 1992;Do, 1998) and new implementations are often introduced (e.g., Talu et al., 1998). Two streams with different initial tracer concentrations flow along the two opposite sides of the sample pellet. The total pressure is the same on both sides. A concentration step change is introduced on the top chamber's inlet and the time-dependent concentration responses at the two chamber outlets are used to estimate the parameters of mass transport across the pellet. A complete review of the technique was given by Park et al. (1 996).This work deals with the particular case of a film mass transfer resistance being present in series with the intra-pellet diffusion. The existence of such resistance complicates the parameter estimation process and loss of precision and sensitivity may occur in the estimation of the effective diffusivity. In the literature, it is often assumed that this resistance is negligible (Dogu and Smith, 1975; Burghardt et al., 1988; Sortichos, 1992), but without establishing the conditions for the verification of such hypothesis. Lu and Rodrigues (1992), on the other hand, developed a criteria based on the first moment of the system's response data, in order to quantitatively define a parametric region for neglecting film resistance, in the case of a diffusion-cell where intrapellet diffusion and convection take place simultaneously and film resistance was present only in the bottom chamber side.This study discusses the development of a general strategy for determining the conditions, in terms of the problem's parameters, where film resistance may be neglected. This particular study is restricted to the case of no 'Author to whom correspondence may be addressed: E-mail address: ccosta@ fe.up.ptIn a diffusion cell experiment, the presence of a film diffusion resistance, in series with intrapellet diffusion, leads to loss of precision in the estimation of intrapellet diffusivities. A general strategy, extendable to other problems, for quantifying a parametric region where f...

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Single‐pellet cell for the measurement of intraparticle diffusion and convection

Cited by 9 publications

References 22 publications

One‐sided single‐pellet technique for adsorption and intraparticle diffusion

One‐sided single‐pellet technique for adsorption and intraparticle diffusion

Single‐pellet technique for irreversible and reversible adsorption in soil

An approach for the optimization of transient diffusion cell measurements

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