(275e) Limitations of the Axial Dispersion Term in the Axial Dispersed Plug Flow Model

Ebner, A. D., University of South Carolina
Knox, J. C., Marshall Space Flight Center
LeVan, M. D., Vanderbilt University
Ritter, J. A., University of South Carolina
Wang, Y., Vanderbilt University

Predictive modeling has the potential to accelerate development of sorption systems (vs. hardware testing only). Limiting the magnitude of the axial dispersion coefficient is critical for predictive capability and applicable to many existing 1-D models currently in use. However, the definition of a general guideline has not been established. In addition, existing modeling approaches either fail to capture high axial dispersion effects or are too specific and unwieldy for general use. Development of a general approach to capture axial dispersion is highly desirable for all areas of adsorption process design. This paper examines the factors that contribute to a loss of predicative capability for a commonly used adsorption model, the axially dispersed plug flow model. A series of parametric simulations are described. Based on these simulations, limitations on the axial dispersion coefficient are suggested as a function of isotherm non-linearity as defined by the separation factor.