Frequency response of continuous-flow adsorber for multicomponent system

Park, In-Soo; Kwak, Chul; Hwang, Young-Gi

doi:10.1007/bf02699121

Cited by 11 publications

(9 citation statements)

References 23 publications

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“…Adsorption data of Chen and Yang [95] for binary CO 2 and C 2 H 6 in 4A zeolite was used to theoretically investigate mixture FR behavior by Sun et al [81] for a closed FR apparatus, by Wang and LeVan [96] for a flow-through PSFR apparatus, and by Park et al [61] for a continuous flow CSFR system. All simulation results showed that the response curves of the faster-diffusing component (CO 2 ) was strongly influenced by the slower component (C 2 H 6 ).…”

Section: Multi-component Mixtures In Microporous Materialsmentioning

confidence: 99%

“…Besides VSFR, another type of widely used FR is a flowthrough technique which involves perturbations in inlet flow rates, pressure, or inlet concentrations [15,18,20,[56][57][58][59][60][61][62][63][64]. Compared to batch FR, the flow-through FR methods have the advantage of minimizing heat effects and flexible operation through a wide range of concentrations.…”

Section: Introductionmentioning

confidence: 99%

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Identification of mass transfer resistances in microporous materials using frequency response methods

Wang

2021

Adsorption

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The frequency response (FR) method, a pseudo-steady state relaxation technique employing perturbation frequency, plays an essential role in discriminating between multi-kinetic mechanisms in microporous materials for separation and catalytic processes. Experimental and theoretical principles are reviewed for three frequency response methods, including one commonly used batch system with volume perturbation and two recently developed flow-through systems with pressure or concentration oscillation. Even though these methods have different overall transfer functions, they can be linked closely through the adsorbed-phase functions, which account for individual or coupling of mass transfer resistances and heat effects. Mass transfer resistances include micropore diffusion, macropore diffusion, surface barriers, and external film resistance. By judicious application of FR methods, it is not only possible to identify dominating mass transfer resistances but also to extract reliable mass transfer coefficients based on corresponding mathematical models. Representative examples to display the ability of the FR methods in studies of zeolites, carbon molecular sieves, and other microporous materials are discussed. Mixture studies and future developments, including nonlinear frequency response and chemical reactions, have also been briefly described.

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Section: Multi-component Mixtures In Microporous Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Identification of mass transfer resistances in microporous materials using frequency response methods

Wang

2021

Adsorption

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“…Sun with associates studied theoretically FR behavior of multiple sorbates diffusion in adsorbents (Sun et al 1994). Park and co-workers analyzed the FR of a continuous-flow adsorber with periodic modulation of the inlet flow-rate in order to measure multicomponent diffusion kinetics in porous media (Park et al 2000). Wang and LeVan used the pressure-swing FR method to investigate mixture diffusion in nanoporous adsorbents theoretically and experimentally LeVan 2005a, 2005b).…”

Section: Introductionmentioning

confidence: 98%

Theoretical investigation of the adsorption of a binary mixture in a chromatographic column using the nonlinear frequency response technique

2007

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The nonlinear frequency response of a chromatographic column for the adsorption of two dissolved components is analyzed using the concept of higher order frequency response functions (FRFs) which is based on the Volterra series and generalized Fourier transform. By applying this concept a nonlinear model of a system is replaced by an infinite series of the FRFs of the first, second, etc. order. The FRFs up to the third order are derived theoretically starting from the equilibrium-dispersive model, which is used for description of a chromatographic column, and applying the harmonic probing method. The functions that relate outlet concentration changes of each component to the corresponding inlet concentration changes are derived. At the inlet of a chromatographic column, it is considered: (a) the concentration change of one of the components keeping the concentration of the other component constant and (b) the concentration change of both components keeping their ratio constant. The FRFs are calculated numerically for different steady-state concentrations and relative mixture compositions. It has been found that, despite certain differences in initial conditions, the FRFs exhibit similar behavior. For higher frequencies, the amplitudes of the FRFs tend to zero and phases to −∞. In the low frequency range, which is A. Seidel-Morgenstern Otto von Guericke University, Chair of Chemical Process Engineering, Magdeburg, Germany of interest for investigation of equilibrium parameters, these functions have similar behavior, but tend to different asymptotic values. Correlations between coefficients of competitive adsorption isotherms, i.e. partial isotherm derivatives, and the derived FRFs are established. This theoretical result offers the potential to use the analysis of the nonlinear frequency response of a chromatographic column for estimation of competitive adsorption isotherms.Keywords Binary mixture · Competitive adsorption isotherm · Nonlinear frequency response · Higher order frequency response functions Abbreviations a ij

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“…pared to batch systems . Even though the FR technique has been shown to be very powerful in measurement of pure component kinetics, it has very few applications in multicomponent systems (Yasuda et al, 1988;Yasuda and Matsumoto, 1989;Shen and Rees, 1995) and the related analysis is scarce Park et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

New Developments in Flow-Through Apparatus for Measurement of Adsorption Mass-Transfer Rates by Frequency Response Method

Wang

LeVan

2005

Adsorption

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A new flow-through frequency response method based on a sinusoidal modulation of pressure is developed to measure gas adsorption equilibria and kinetics simultaneously. The transfer phenomena of pure N 2 and O 2 gases in carbon molecular sieve are investigated for different pressures and particle sizes by this method. Also, this apparatus has been extended to measure data for mixtures at different compositions at atmospheric pressure and room temperature. This is the first application of the flow FR system for a mixture. A negative cross-term diffusivity is reported. It shows that for co-diffusion, the fast diffusing molecule O 2 is decelerated by the slow diffusing molecule N 2 , and the slower moving molecule N 2 is sped up by the faster moving O 2 . The main-term diffusivities agree with the pure component diffusivities.

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Frequency response of continuous-flow adsorber for multicomponent system

Cited by 11 publications

References 23 publications

Identification of mass transfer resistances in microporous materials using frequency response methods

Identification of mass transfer resistances in microporous materials using frequency response methods

Theoretical investigation of the adsorption of a binary mixture in a chromatographic column using the nonlinear frequency response technique

New Developments in Flow-Through Apparatus for Measurement of Adsorption Mass-Transfer Rates by Frequency Response Method

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