Hydrocracking Kinetic Modeling

Catalytic hydrocracking is a flexible process for the conversion of heavy, hydrogen-deficient oils into lighter and more-valuable produets. Part of its flexibility is its ability to handle a wide range of feeds, from heavy aromatics to paraffinic crudes and cycle stocks. The ability to extend this flexibility to customized product slates depends on the ability to control and manipulate the process chemistry, which is, in turn, enhanced by a rigorous representation of fte process chemistry. This motivates the present interest in a heavy paraffin hydrocracking kinetics model. 

First, Equation 11.55 was solved in order to find the hydrocracking kinetic model parameters a, Oq, a, 8, and Then, by using these values. Equation 11.71 was resolved and the parameters p, and were found. All routines were written in MATLAB software. The criterion of minimization of the sum of square errors (SSE) obtained from the difference of calculated and experimental points was employed to determine all model parameters. More details of numerical solution of Equation 11.55 can be found elsewhere (Elizalde and Ancheyta, 2011). 

Froment, G.F. Kinetic modeling of complex processes. Thermal cracking and catalytic hydrocracking. In Chemical Reactor Technology for Environmentally Safe Reactors and Products, de Lasa, H.I, Dogu, G., Ravella, A., Eds. Kluwer Academic Publishers Dordrecht, 1992 409-424. 

Baltanas, M. A., Van Raemdonck, K. K., Froment, G. F., and Mohedas, S. R., Fundamental kinetic modeling of hydroisomerisation and hydrocracking on noble-metal-loaded Faujasites 1 Rate parameters for hydroisomerisation, Ind. Eng. Chem. Res. 28, 899-910 (1989). 

Martens, G. G. Hydrocracking on Pt/US-Y zeolites Fundamental kinetic modeling and industrial reactor simulation , PhD Thesis, Ghent University (2000). 

Schweitzer, J. M., Galtier, P., and Schweich, D., A single events kinetic model for the hydrocracking of paraffins in a three-phase reactor, Chem. Eng. Sci. 54(13-14), 2441-2452 (1999). 

Castano P, Arandes JM, Pawelec B, Olazar M, Bilbao J. Kinetic modeling for assessing the product distribution in toluene hydrocracking on a Pt/HZSM-5 catalyst Industrial and Engineering Chemistry Research 2008 47 1043-1045. 

Baltanas MA, Vanraemdonck KK, Froment GF, Mohedas SR. Fundamental kinetic modeling of hydroisomerization and hydrocracking on noble-metal-loaded faujasites. 1. Rate parameters for hydroisomerization. Ind. Eng Chem. Res. 1989 28 899-910. 

Kumar H, Froment G. Mechanistic kinetic modeling of the hydrocracking of complex feedstocks, such as vacuum gas oils. Ind. Eng Chem. Res. 2007 46 5881-5897. 

MECHANISTIC KINETIC MODELING OF HEAVY PARAFFIN HYDROCRACKING... 

This chapter describes the application of these tools to the development of a mechanistic kinetic model for the catalytic hydrocracking of heavy paraffins. The basic approach and overview synopsis are presented first. This is followed by a detailed description of the steps involved in model formulation, optimization, and use. 

Mechanistic Kinetic Modeling of Heavy Paraffin Hydrocracking... 

Catalytic reforming models developed by Kmak and Ramage et al. give a fairly detailed description of the process. In Powell s hydrocracking modeP, the chemical composition parameters are continuous functions of carbon numbers. Quann and Krambeck developed a kinetic model for olefin oligomerization over the ZSM-5 catalyst. 

Stangeland, B.E. Kinetic Model for the Prediction of Hydrocracker Yields, Industrial Engineering Chem., Process Des. Development, 13(1), 1974,71. 

The simple kinetic model for coal liquefaction presented here appears to correlate well the experimentaHy observed effects of space time and temperature on coal solvation and the production of oils. The model must be refined further to account for hydrogen donor and hydrocracking reactions and to properly explain the effect of pressure on the liquefaction process. 

KINETIC MODELING OF COMPLEX PROCESSES. THERMAL CRACKING AND CATALYTIC HYDROCRACKING... 

ABSTRACT. A fundamental approach is outlined for the kinetic modeling of complex processes like thermal cracking or catalytic hydrocracking of mixtures of hydrocarbons. The reaction networks are written in terms of radical mechanisms in the first case and of carbenium ion mechanisms in the second case. Since the elementary steps of the networks pertain to a relatively small number of classes, the number of rate coefficients is kept within tractable limits. The reaction networks are generated by computer through Boolean relation matrices. The number of continuity equations is limited by the elimination of radicals or carbenium ions through the pseudo-steady-state approximation. 

Kinetic Modeling of Catalytic Hydrocracking 3.1. LUMPED SCHEMES... 

The present paper has outlined an approach for the detailed kinetic modeling of both thermal cracking and catalytic hydrocracking. The parallelism between the two cases is remarkable. Expressing the rate equations in terms of elementary steps and single events of either radical or carbenium ion chemistry keeps the number of rate parameters within practical limits. The approach should stimulate the commitment of oil and petrochemical companies to the improvement and refinement of their analytical means. 

Kinetic Modelling of Complex Processes. Thermal Cracking and Catalytic Hydrocracking P. Trambouze 409... 

The catalytic hydrocracking of heavy oil has been well represented by the five-lump kinetic model shown in Figure 6.15 (Sdnchez et al., 2005). Although catalytic and thermal reactions follow different mechanisms, the same kinetic model was used to represent the NHDC. Hydrocracking of vacuum residue was assumed to follow second order as demonstrated earlier, while first order was considered for the other reactions. The reaction rate (r for each lump as a function of the product composition (y and the corresponding kinetic constant k is as follows ... 

Sanchez, S., Rodriguez, M.A., Ancheyta, J. 2005. Kinetic model for moderate hydrocracking of heavy oils. Ind. Eng. Chem. Res. 44 9409-9413. 

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