Kinetic fluid catalytic cracking

A number of mechanistic modeling studies to explain the fluid catalytic cracking process and to predict the yields of valuable products of the FCC unit have been performed in the past. Weekman and Nace (1970) presented a reaction network model based on the assumption that the catalytic cracking kinetics are second order with respect to the feed concentration and on a three-lump scheme. The first lump corresponds to the entire charge stock above the gasoline boiling range, the second... 

Lee, L.S., Chen, T.W., Haunh, T.N., and Pan, W.Y. (1989) Four lump kinetic model for fluid catalytic cracking process. Canadian Journal of Chemical Engineering, 67, 615. 

A model for the riser reactor of commercial fluid catalytic cracking units (FCCU) and pilot plants is developed This model is for real reactors and feedstocks and for commercial FCC catalysts. It is based on hydrodynamic considerations and on the kinetics of cracking and deactivation. The microkinetic model used has five lumps with eight kinetic constants for cracking and two for the catalyst deactivation. These 10 kinetic constants have to be previously determined in laboratory tests for the feedstock-catalyst considered. The model predicts quite well the product distribution at the riser exit. It allows the study of the effect of several operational parameters and of riser revampings. 

Weekman Jr., V.W. and D.M. Nace, Kinetics and Catalytic Cracking Selectivity in Fixed, Moving and Fluid-Bed Reactors., AIChE Joum., 16,397,1970. 

A. Marcilla, A. Gomez, J. A. Reyes-Labarta, A. Giner and F. Hernandez, Kinetic study of polypropylene pyrolysis using ZSM-5 and an equilibrium fluid catalytic cracking catalysts. J. Anal. Appl. Pyrolysis, 68-69, 467-480 (2003). 

The main problem in case of thermocatalytic cracking of polymers is the activity loss of catalysts therefore first-order kinetics is applicable only with some simplifications in thermocatalytic cases. On the other hand there is a relation modelling the fluid catalytic cracking taking into consideration the catalyst deactivation in refineries [31] ... 

Weekman, V. W., and Nace, D. M., Kinetics of catalytic cracking selectivity in fixed, moving and fluid-bed reactors. AIChEJ. 16,397 (1970). 

We have in our files about 500 published papers that report studies or contain kinetic equations of deactivation of solid catalysts of which about 50 contain kinetic equations of deactivation of the catalysts for the FCC (fluid catalytic cracking) process. Thus, much could be said on the subject especially since each author in the field uses his own approach and experimental technique. In addition, the literature used is different from one author to another which, in turn, makes possible a lot of different bases and approaches. Thus, for the FCC process each author and oil company lend to use their own model and kinetics, making it difficult to arrive at new approaches and optimum parameters of deactivation, especially if one is already comfortable with an approach and its corresponding parameters. 

Yen eta/ [1988] Fluid catalytic cracking Coke formation is kinetics control with fourth order reaction None considered (1) Complex - many parameters (2) Tested against actual coke data from both pilot and commercial fluid catalytic cracking units... 

Lee, L.L., Chen, Y.W., Huang, T.N. and Pan, W.Y. 1989, Four-Lump Kinetic Model for Fluid Catalytic Cracking Process, The Canadian Journal of Chem. Engng., 67, pp. 615-619. 

Also, in many situations, the pseudo-kinetics expression is used owing to the lack of detailed kinetics information or for simplicity. Useful pseudo-kinetics can oifly be obtained in an environment as close as possible to that of the proposed commercial operations. For instance, the catalyst decay in a FCC (fluid catalytic cracking) system is mainly caused by... 

Corella, J., Fernandez, A. and Vidal, J.M., "Pilot Plant for the Fluid Catalytic Cracking Process Determination of the Kinetic Parameters of Deactivation of the Catalyst", Ind. Eng. Chem. Proc. Des. Dev., 25, 554-562 (1986). 

Ancheyta, J., Sotelo, R. 2000. Estimation of kinetic constants of a five-lnmp model for fluid catalytic cracking process using simpler sub-models. Energy Fuels 14 1226-1231. 

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