Pore and solid diffusion models for fixed‐bed adsorbers

AICHE Journal - Tập 20 Số 2 - Trang 228-238 - 1974
Thomas Weber1, Ranjit K. Chakravorti1
1Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 1421

Tóm tắt

AbstractMost models for fixed bed adsorbers have used either the homogeneoussolid or pore diffusion model for the pellets. When the adsorption isotherm is linear, the two models can lead to identical breakthrough curves. The conditions for this equivalence are presented here. It is shown that one of the bulk flow factors that was included in the formulation of one pore diffusion model will be significant only for feedstreams containing a relatively high concentration of adsorbate. The prosity factor of the pore model is shown to be very important, especially as the porosity decreases. The importance of the two diffusional models with respect to the predicted breakthrough curves is demonstrated. For comparable beds, it is shown that the breakthrough curve based on the homogeneous model is delayed with respect to that based on the pore model at early times, regardless of the shape of the isotherm. Finally, the various possible solutions for an irreverisble isotherm are reviewed for each of the models, and a solution is presented for the general case of a pore model with an outside film resistance.

Từ khóa


Tài liệu tham khảo

Allen P. W.“Unsteady‐State Diffusion in Porous Media ” Ph.D. thesis Univ. of Colorado Boulder (1968).

10.1021/j150463a007

10.1021/j150480a010

10.1021/i160032a011

Brecher L. E., 1967, Combined Diffusion in Batch Adsorpation Systems Displaying B.E.T. Isotherms: Part I, AIChE Symp. Ser., no. 74, 64, 18

Brecher L. E., 1967, Combined Diffusion in Batch Adsorption Systems Displaying B.E.T. Isotherms, Part II, ATChE Symp. Ser. No. 74, 63, 25

10.1098/rspa.1954.0056

Carter J. W., 1966, A Numerical Method for Prediction of Adiabatic Adsorption in Fixed Beds, Trans. Instn. Chem. Engr., 44, T253

10.1002/aic.690120213

Clowell C. J. andJ. S.Dranoff “The Kinetics of Sorption by Ion Exchange Resin beds ”AIChE J. 304.

10.1021/i160030a003

10.1021/i160037a012

10.1021/i160015a012

10.1021/i160036a016

Damköhler G., 1935, Uber die Adsorptiongeschwindigkeit von Gasen an porösen Adsorbention, Z. Physik. Chem., 174, 222, 10.1515/zpch-1935-17421

Dedrick R. L., 1967, Kinetics of Adsorption by Activated Carbon from Dilute Aqueous Solution, AIChE Symp. Ser. No. 74, 63, 68

10.1021/ie50539a023

10.1021/ie50487a016

10.1021/ie50511a058

10.1021/j150493a029

10.1021/i160046a009

10.1039/TF9555101540

10.1021/i160018a011

Hsieh J. S., 1971, Batch Adsorption Kinetics in Sewage‐Activated Carbon, Proc. Am. Soc. Civil Eng. J. Sant. Eng. Div., 4, 505

10.1021/j150498a004

Kondis E. F., 1971, Nonisothermal Sorption of Ethane by 4A Molecular Sieves, AIChE Symp. Ser., No. 117, 67, 25

10.1021/j150495a019

Lee H., 1971, Carbon Dioxide Remooval from Air by Sodium‐X Molecular Sieve Under Nonisothermal Conditions, AIChE Sypmp. Ser., No. 117, 67, 84

10.1002/cjce.5450470110

Lee R. G., 1969, Interpretation of Methdane Adsorption on Activated Carbon by Nonisothermal and Isothermal Calculations, Can. J. Chem. Eng., 60

10.1016/0009-2509(70)85070-9

10.1002/aic.690100222

10.1021/i160010a016

10.1002/aic.690110111

Masamune S., 1965, Adsorption of Ethyl Alcohol on Silica Gel, AIChE J., 41

10.1002/aic.690130314

10.1002/aic.690160204

10.1002/aic.690130526

10.1002/aic.690160623

10.1088/0959-5309/59/1/310

10.1002/aic.690140107

10.1063/1.1700431

10.1021/ie50536a026

Smith S. B., 1959, Kinetics of Batch Adsorption of Dichlorophenol on Activated Carbon, AIChE Symp. Ser., No. 24, 55, 25

Testin R. F., 1967, Diffusion Coeffecients Measured from Gas‐Solid Adsorption Rate Experiments, AIChE Symp. Ser. No. 74, 63, 10

10.1063/1.1748515

10.1002/aic.690050323

10.1002/aic.690060305

10.1002/cjce.5450380104

10.1002/aic.690070313

10.1002/aic.690110520

Vermeulen T., 1958, Advances in Chemical Engineering, 147

10.1021/ie50524a025

10.1029/WR001i003p00361

10.1007/BF01511392

10.1080/14786444808561166

Thông tin
Thông tin xuất bản

AICHE Journal

Tập 20 Số 2

228-238

Thông tin tác giả