Modeling of rotating annular chromatographic reactor – application of statistical moments to indicate reasonable model simplifications
Advancing the chemical engineering fundamentals
Chemical Reaction Engineering (T2-2P)
Keywords: rotating annular chromatographic reactor, statistical moments, process integration, reactor modeling
Abstract
In chromatographic reactors the chemical reaction and the chromatographic separation of the reaction products are integrated in one apparatus. Due to a synergic interaction between reaction and separation, an application of such an integrated process allows to improve the reaction selectivity as well as the productivity of the entire process. These advantages are particularly significant for reversible reactions. Reactive chromatography can be carried out in the simulated moving bed chromatographic reactors (SMBCRs) as well as in the rotating annular chromatographic reactors (RACRs). SMBCRs are now frequently used in a laboratory and a preparative scale, while an application of RACRs helps to avoid the main disadvantage of SMBCRs, in which only the reactions with maximal two products can be effectively carried out.
Modeling, design and optimization of chromatographic reactors is not a trivial task, because of complexity of the entire process. Evaluation of significance of each stage process and its contribution to the integrated process is the most important step in model formulation, giving indications to reasonable simplifications of a general model.
In this study the statistical moments have been employed for this purpose. Statistical moments of the chromatographic peaks can be directly expressed in terms of the process parameters. So, the proposed method makes possible a quantitative estimation of a contribution of each stage process to the entire process. In a general model the following stage processes are taken into account: - mixing of the moving phase in the interparticle voids of the bed (convection and dispersion), - mass transfer from the moving phase into the solid particles, - internal diffusive transport in pores of the adsorbent and the catalyst grains, - rate of the adsorption as well as - adsorption equilibrium and - chemical (homogeneous or heterogeneous) reaction. Basing on the results of the performed quantitative analysis, important indications for reasonable simplifications of a general reactor model have been formulated. These indications have been generalized, giving practical maps of process parameters as well as operating conditions for which a chosen simplification of the general reactor model holds.
Presented Tuesday 18, 13:30 to 15:00, in session Chemical Reaction Engineering (T2-2P).
