Ahmadi, Aras and Meyer, Michel and Rouzineau, David and Prevost, Michel and Alix, Pascal and Laloue, Nicolas Rigorous Multicomponent Reactive Separations Modelling : Complete Consideration of ReactionDiffusion Phenomena. (2010) Oil & Gas Science and Technology, vol. 65 (n° 5). pp. 735749. ISSN 12944475

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Official URL: http://dx.doi.org/10.2516/OGST/2010009
Abstract
This paper gives the first step of the development of a rigorous multicomponent reactive separation model. Such a model is highly essential to further the optimization of acid gases removal plants (CO2 capture, gas treating, etc.) in terms of size and energy consumption, since chemical solvents are conventionally used.Firstly, two main modelling approaches are presented: the equilibriumbased and the ratebased approaches. Secondly, an extended ratebased model with rigorous modelling methodology for diffusionreaction phenomena is proposed. The film theory and the generalized MaxwellStefan equations are used in order to characterize multicomponent interactions. The complete chain of chemical reactions is taken into account. The reactions can be kinetically controlled or at chemical equilibrium, and they are considered for both liquid film and liquid bulk. Thirdly, the method of numerical resolution is described. Coupling the generalized MaxwellStefan equations with chemical equilibrium equations leads to a highly nonlinear DifferentialAlgebraic Equations system known as DAE index 3. The set of equations is discretized with finitedifferences as its integration by Gear method is complex. The resulting algebraic system is resolved by the Newton Raphson method. Finally, the present model and the associated methods of numerical resolution are validated for the example of esterification of methanol. This archetype nonelectrolytic system permits an interesting analysis of reaction impact on mass transfer, especially near the phase interface. The numerical resolution of the model by NewtonRaphson method gives good results in terms of calculation time and convergence. The simulations show that the impact of reactions at chemical equilibrium and that of kinetically controlled reactions with high kinetics on mass transfer is relatively similar. Moreover, the Fick’s law is less adapted for multicomponent mixtures where some abnormalities such as counterdiffusion take place.
Item Type:  Article 

Audience (journal):  International peerreviewed journal 
Uncontrolled Keywords:  
Institution:  French research institutions > Centre National de la Recherche Scientifique  CNRS (FRANCE) Université de Toulouse > Institut National Polytechnique de Toulouse  INPT (FRANCE) French research institutions > IFP Energies Nouvelles  IFPEN (FRANCE) Université de Toulouse > Université Paul SabatierToulouse III  UPS (FRANCE) 
Laboratory name:  Laboratoire de Génie Chimique  LGC (Toulouse, France)  Réaction, mélange & séparation (RMS) 
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Deposited By:  Audrey LEFEVRE 
Deposited On:  12 Jun 2012 14:21 
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