In recent years, CFD has played an important role in the understanding and design of TBR’s. In this work, through CFD with Eulerian approach, a three-phase heterogeneous reactor model was developed, were the accuracy of Interfacial Momentum Exchange Model (IMEM) for the gas-solid interaction, the effect of a more detailed catalytic bed geometry description, and the pellet shape over TBR hydrodynamics of two fluid phases interacting with the solid phase was studied. Then, a second model was developed, where the validated hydrodynamic model was coupled with mass transport for an HDS process of light gasoil. Additionally, in order to insight into the scaling up process of a TBRs, the proposed columns behaviors were compared against literature columns using four different ways, and it was found that the best predictions were obtained when the models’ holdup were equaled to those evaluated in literature columns. Since in reliable literature deviations in pressure drop predictions of around 30% can be found, the model results show significant improvement against literature, achieving 5 times better accuracy in predicting pressure drops, and 50% improvement in holdup prediction; the coupled model reproduces the same conversion values compared with literature data, and predicts conversions with 95% accuracy

A method to obtain the approximate solution to the diffusionreaction problem with nonlinear kinetics in transient systems is presented. The analytical solution to the equation that governs the process is based on the linearization of the kinetics expression through the Taylor series expansion above the surface particle concentration of the key component, which includes a critical radius to avoid negative concentration values. The present results for the average concentration were compared with the numerical solution of the exact problem and the error was less than ten percent for the power-law and Monod kinetics equation.

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This work studies loop control composition in continuous chemical reactors with simple structures, due to its large acceptance in chemical industry. A linear cascade composition control (master/slave) is proposed, designed with basic control structures based on Laplace tools. Two configurations are designed, which were evaluated in a dynamic model of continuous stirred tank. From a stability analysis it is noted that, for such configurations, system assent time is 7 to 8 times reduced if compared to the assent time without loop control. Besides, the system shows a good performance when coming to the asked reference. Implementation of such control configurations can solve the problem of loop control composition.