Critical Evaluation of Mathematical Models Used for Dynamic Adsorption of Hydrocarbons

Abstract

In the process of analyzing a large amount of dynamic adsorption data for hydrocarbons a number of existing mathematical models have been used. Even though many of these can be used to "fit" the data to varying degrees, they involve assumptions that are incompatible with the proved physical mechanisms involved and/or are incapable of describing the concurrent adsorption of several adsorbates. Therefore, the ability of a model to fit the data has only empirical significance. Data are presented which illustrate

Fixed bed desorption behavior of gases with nonlinear equilibria: Part II. Dilute, multicomponent, isothermal systems

“…In multicomponent systems, the interactions between components give rise to instabilities in the gas concentration (Figures 1 and 2 ) and adsorbent loading profiles which further complicate the relationship between adsorption and desorption. The adsorption of binary systems was initially described by Needham et al (1966), and in gr-ater detail, using both experimental and theoretical results, by Gariepy and Zwiebel (1971) and by Thomas and Lombardi (1971). In this paper both calculated and experimental depletion curves are presented for binary systems; their behavior is correlated with the isotherm nonlinearities and related parameters, and they are contrasted with the corresponding breakthrough phenomena.…”

Rates of Adsorption in the Benzene-Hexane System

“…Experimental data for rates of adsorption of mixtures are also limited. The closest reference to the present work is that of Needham et al (1966) on the adsorption of binary hydrocarbon gases on silica gel. There results showed strong interaction effects which make it impossible to analyze the data.…”

Fixed Bed Adsorption with Variable Gas Velocity Due to Pressure Drop

“…of some of these assumptions. Edeskuty and Amundson (1952), Masamune and Smith (1964), Needham et al (1966), and others studied the mass transfer mechanism by using more complicated rate models, particularly those which include diffusion within the solid phase. Vermeulen (1958) and Fosberg et al (1967) considered the case of nonlinear equilibrium behavior, specifically the Langmuir isotherm.…”