Chemical Reactors II
Objectives
This course consists of two distinct parts : ANALYSIS OF NON- IDEAL REACTORS and HETEROGENEOUS CATALYTIC REACTORS. With the first part is intended to provide students with the tools needed to evaluate the deviation from ideality, either through the diagnosis of the causes that lead to such deviation either through mathematical models predicting the behavior of the real reactor. In the second part it is intended that on the end of the course students are able to determine the amount of catalyst and the reactor volume necessary for a given conversion. In particular will be dealt with fixed-bed, moving bed and monolithic reactors operating under kinetic or mass transfer control, either externally or intraparticular . Special attention is given to the deduction of rate law from the mechanisms of Langmuir – Hinshelwood and Eley-Rideal , the calculation of the coefficient of mass transfer from the relations between the dimensionless numbers, for the case of external diffusion regime, and the determination Thiele modulus and effectiveness factor, in case of internal diffusion regime.
General characterization
Code
10683
Credits
6.0
Responsible teacher
Teresa Maria Alves Casimiro Ribeiro
Hours
Weekly - 4
Total - 70
Teaching language
Português
Prerequisites
Available soon
Bibliography
H. Scott Fogler, Elements of Chemical Reaction Engineering, 4rd edition, Prentice-Hall, 2006.
J.L. Figueiredo and F. Ramôa Ribeiro, Catálise Heterogénea, Fund. Calouste Gulbenkian, 1989.
Francisco Lemos, José Madeira Lopes, Fernando Ramôa Ribeiro, "Reactores Químicos", IST Press, Lisboa 2002
J.F. Le Page, J. Cosyns, P. Courty, E. Freund, J.P. Franck, Y. Jacquin, B. Juguin, C. Marcilly, G. Martino, J. Miquel, R. Montarnal, A. Sugier, H. van Landeghem, "Catalyse de Contact", Technip, Paris, 1978.
Teaching method
The teaching methods include:
- Lectures with PP presentations;
- Laboratory sessions and results modeling using Excel;
- Problem solving sessions.
Evaluation method
The course evaluation is composed by a written part and a practical part. The written part consists in two tests or in a final exam. The grade in each test must be equal or higher than 9,45/20.
The final grade is the weithed average of the written (70%) and the practical (30%) parts . Approval ios obtained with the final grade equal or higher than 9,45/20 and the grade of the written part not less than 9,454/20.
Frequency is mandatory and is obtained with the practical part. It will remain valid for a period of two years.
The grades can be improved through the repetition of the written or practical parts. In any case the final grade is calculated as described above.
Subject matter
THEORETICAL PART
Nonideal reactors
Characterization of flow by use of tracers
Modeling real reactors by association of ideal reactors
Catalysis and catalytic reactors
Adsorption isotherms. Mechanisms of Langmuir - Hinshellwood and Eley – Rideal. Dimensioning the fixed bed reactor working under kinetic control.
Deactivation of catalysts. Dimensioning the moving bed reactor
External mass transfer and chemical reaction
Determination of the mass transfer coefficient from correlations between dimensionless numbers.
Monolithic reactor and fixed bed reactor working under external mass transfer control.
Catalyst regeneration : the "Shrinking Core " model.
Simultaneous reaction and internal diffusion.
Mole balance to a catalyst pellet. The Thiele modulus and the effectiveness factor.
PRACTICAL
Determination of the residence times distribution in a bench scale CSTR reactor
Reaction of crystal violet with sodium hydroxide. Comparison of the experimental value of conversion with values calculated from proposed models.
Determination of the residence times distribution a CSTR pilot reactor
Transesterification of ethyl acetate with methanol catalyzed by resin DOWEX 50W-X8. Study of the effects of the pellets size on the apparent reaction rate. Determination of Thiele modulus, effectiveness factors, intrinsic kinetic constant and effective diffusivity.
Processing of data obtained in the laboratory using common software.
THEORETICAL-PRACTICAL PART
Problems resolution