A lumping and reaction scheme for catalytic cracking

Abstract

A predictive kinetic model has been developed for fluid catalytic cracking (FCC). The kinetic scheme involves lumped species consisting of paraffins, naphthenes, aromatic rings, and aromatic substituent groups in light and heavy fuel oil fractions. The kinetic model also incorporates the effect of nitrogen poisoning, aromatic ring adsorption, and time dependent catalyst decay. The rate constants for these lumped species are invariant with respect to charge stock composition. The predictive capabilities of the model have been verified for wide ranges of charge stocks and process conditions.In this work, a wide variety of charge stocks were cracked in a fluidized dense-bed reactor. Detailed analysis of the molecular compositions of the charge stocks and products provided the necessary data to develop a predictive kinetic model. Rate constants and activation energies were calculated for lumped species including paraffins, naphthenes, aromatic rings, and aromatic substituent groups. The reliability of the kinetic predictions for various charge stocks over a wide range of process conditions has been shown. CONCLUSIONS AND SIGNIFICANCEThe reaction kinetics of catalytic cracking is presented, based on a reaction scheme that includes paraffins, naphthenes, aromatic rings, and aromatic substituent groups in light and heavy fuel oil fractions. The kinetic model also accounts for nitrogen poisoning, aromatic adsorption, and time dependent catalyst decay. The conversion of Gross.Correspondence concerning this paper should be addressed to Benjamin these lumped species to gasoline, light products, coke, heavy fuel oil, and light fuel oil can be readily calculated by these kinetics. In addition, the detailed composition of the heavy and light fuel oil fractions can be tracked, increasing the utility of the model for predicting recycle behavior and physical properties of the products. The invariant kinetic parameters (rate constants and activation energies) allow the conversion and product selectiv-dimensions and operating conditions for maximum thermal efficiency and/or McGill University minimum operating cost. Application of these basic principles is illustrated Montreal, Quebec by the design of an industrial size, spray drying chamber for a specific feed solution and production rate. SCOPEThe growing importance of spray drying is abundantly evident from the ever increasing number of industrial applications in the production of pharmaceuticals, detergents, food products, pigments, ceramics, and a large number of organic and inorganic chemical compounds. In sylvania.

Study of Seven-Lump Kinetic Model in the Fluid Catalytic Cracking Unit

“…Hagelberg et al (2002) expanded the 5-lump model of Ancheyta-Juarez et al (1999) to an 8-lump model by dividing the gasoline fraction into paraffins, olefins, naphthenes and aromatics. The more advanced model was proposed by Jacob et al (1976) which included 10 lumps (light and heavy gas oil paraffinic, naphthenic and aromatic rings and substituent). On the basis of the 10-lump model of Jacob et al (1976); Ellis et al (1998) developed a more advanced model capable of predicting the light gas product slate, using empirical algebraic equations.…”

“…The more advanced model was proposed by Jacob et al (1976) which included 10 lumps (light and heavy gas oil paraffinic, naphthenic and aromatic rings and substituent). On the basis of the 10-lump model of Jacob et al (1976); Ellis et al (1998) developed a more advanced model capable of predicting the light gas product slate, using empirical algebraic equations. With presence of the high efficiency feed injection system in modern FCC units cause all cracking in the riser occur during the short time about 1-5 sec (Arandes and de Lasa, 1992;Arbel et al, 1995;Han and Chung, 2001;, so in the present research, a one-dimensional isothermal for the FCC unit riser has been developed that combines a predicative riser hydrodynamic model with a seven-lump kinetic model.…”

Application of biologically based computer modeling to simple or complex mixtures.

“…In an attempt to describe hydrocarbon mixture properties, early models relied on the techniques of lumping (24), where a relatively small number of lumps were used to describe the mixture. In these coarsely lumped kinetic models, thousands of individual constituents in a complex feedstock were grouped into broad but measurable categories of compound classes or boiling range, with simplified reaction networks between the lumps.…”

Gas-Solid Heat and Mass Transfer Intensification in Rotating Fluidized Beds in a Static Geometry

“…The basic set of continuity equations, shown in Table 1, has to be extended to account for the reactions between different species. The catalytic cracking of gas oil was described by a 10-lump model, shown in Figure 9 [Jacob et al, 1976]. The C-lump is a mixture of coke and light gases (C 1 -C 4 ).…”