An analysis of adiabatic sorption of single solutes in fixed beds: equilibrium theory

Pan, C.Y.; Basmadjian, Diran

doi:10.1016/0009-2509(71)86080-3

Cited by 56 publications

(18 citation statements)

References 6 publications

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“…Di erent theoretical developments were proposed (e.g. Pan and Basmadjian, 1971;, which allowed the study of the e ects of the feed temperature, the feed concentration, etc. It appeared that if the temperature overshoots due to the components adsorption are of importance, the performances of the adsorption step may be drastically limited.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of gas mixtures in TSA adsorbers under various heat removal conditions

Clausse

Bonjour

Meunier

2004

Chemical Engineering Science

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Section: Introductionmentioning

confidence: 99%

Adsorption of gas mixtures in TSA adsorbers under various heat removal conditions

Clausse

Bonjour

Meunier

2004

Chemical Engineering Science

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“…Many recent theoretical analyses of adiabatic processes in fixed-bed adsorbers have been based on the method of characteristics 1965;Rhee et al, 1970;Pan and Basmadjian, 1971;Banks, 1972;Basmadjian et al, 1975 Ikeda, 1979), the packed bed is modeled as a number of stages, plates, mixing cells, or tanks in series. Our model is obtained by discretizing in the axial direction the partial differential equations for conservation of mass and energy in a fixed bed to obtain ordinary differential equations for each stage.…”

Section: Department Of Chemical Engineeringmentioning

confidence: 99%

Solute condensation in adsorption beds during thermal regeneration

Friday

LeVan

1982

AIChE Journal

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This theoretical study shows that a liquid phase can be developed in and passed through a fixed-bed adsorber during thermal regeneration. The liquid results from passing hot gas from the inlet end of the bed, where the adsorbate is desorbed, towards the cool outlet end, where condensation of the solute occurs. The stage model of an adsorption bed is applied to two examples, the regeneration of an activated carbon bed with adsorbed benzene using hot nitrogen and the regeneration of a 4A molecular sieve bed with adsorbed water using hot methane. DAVID K. FRIDAY andM. DOUGLAS LEVAN Department of Chemical EngineeringUniversity of Virginia Charloitesville, VA 22901 SCOPE Displacement of adsorbed compounds from a fixed-bed adsorber often results from the passage of a hot gas into the column. This process, called thermal regeneration, finds wide application in solvent recovery, dehydration, and liquid treating operations. Following the heating step, the bed is cooled and is then ready for reuse.This work considers theoretically the thermal regeneration of an adiabatic adsorption column with the development of a liquid phase in the bed. The objectives of this paper are, first, to show that the liquid condensate phase can be formed during thermal regeneration and, second, to present a simple yet versatile model that can be used to predict regeneration behavior for various systems and operating conditions. Thorough treatment will lead to improved methods for the design of adsorption systems and to a better fundamental understanding of coupled heat and mass transfer in adsorptive media.The phenomenon of solute condensation has not been investigated previously although a basis for it has been described by Basmadjian et al. (1975). In their study of thermal regeneration of 5A molecular sieve with adsorbed carbon dioxide using nitrogen, a plateau of readsorbed carbon dioxide was predicted for which the adsorbed-phase concentration exceeded the initial loading. Basmadjian et al. referred to this phenomenon as roll-up.Several methods are available that can be applied to this problem. Many recent theoretical analyses of adiabatic processes in fixed-bed adsorbers have been based on the method of characteristics 1965;Rhee et al., 1970;Pan and Basmadjian, 1971;Banks, 1972;Basmadjian et al., 1975 Ikeda, 1979), the packed bed is modeled as a number of stages, plates, mixing cells, or tanks in series. Our model is obtained by discretizing in the axial direction the partial differential equations for conservation of mass and energy in a fixed bed to obtain ordinary differential equations for each stage. As in the method of characteristics approach, the effects of heat and mass transfer resistances are neglected. Since the model used here is based on finite differences, as the number of stages is increased the results for concentration and temperature profiles in the bed approach those given by the method of characteristics.Two systems are examined: the passage of hot nitrogen into a fixed bed of activated carbon with adsorbed benzene, a...

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“…The same systems have also been analyzed using equilibrium models in which heat and mass transfer resistances are neglected (Nordon and Bainbridge, 1972;Banks, 1972;Sutherland et al, 1972). The results of this approach are less quantitative but afford a broader and more comprehensive analysis of nonisothermal fixed bed processes (Pan and Basmadjian, 1971; Basmadjian et al, 1975).…”

Section: Conclusion and Significancementioning

confidence: 99%

“…We had previously shown that these PDE's can be converted, via the method of characteristics, into two alternate forms which represent combined mass and energy balances [Pan and Basmadjian, 1971, Equations (17) and (23~:…”

Section: Construction Of Adiabatic Equilibrium Curves Bed Profiles Amentioning

confidence: 99%

“…As an illustration, we calculate the parameter values required to find the bed position z of the dimensionless moisture ratio (1 - Since z occurs in both parameters Z andNR, an initial guess has to be made and refined by trial and error. We assume z = 0.122 m. From Equation (8) and the-values given in Table 1 Some a priori knowledge of the shape of the adiabatic equilibrium curves may be gained by examining the characteristic ODE'S which arise in the transformation of the equilibrium conservation equations (Pan and Basmadjian, 1971 (Pan and Basmadjian, 1971), we obtain for the shallow branch: and AH' = isosteric heat of adsorption. The equilibrium relation is formally represented by and derivatives of this function are described by the subscripted symbols q*T and q*y.…”

Section: Thus From Figure 4bmentioning

confidence: 99%

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Throughflow drying and conditioning of beds of moist porous solids: A simple method for the quantitative prediction of moisture and temperature fronts

Basmadjian

1980

AIChE Journal

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An analysis of adiabatic sorption of single solutes in fixed beds: equilibrium theory

Cited by 56 publications

References 6 publications

Adsorption of gas mixtures in TSA adsorbers under various heat removal conditions

Adsorption of gas mixtures in TSA adsorbers under various heat removal conditions

Solute condensation in adsorption beds during thermal regeneration

Throughflow drying and conditioning of beds of moist porous solids: A simple method for the quantitative prediction of moisture and temperature fronts

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