Patent ID: 6212488
Filing Date: 2001-04-03
Classification: C10G,G16C

Abstract:
A method for mathematically modeling a catalytic cracking reaction wherein a feed stream containing a multiplicity of complex hydrocarbon molecules having various boiling points is contacted with an active catalyst in a riser reactor under catalytic cracking conversion conditions to produce a desired reaction product of lower molecular weight, said method comprising the following steps;(a) lumping said multiplicity of complex hydrocarbons according to boiling-range into a plurality of model lumps, said model lumps including:i) a plurality of product lumps comprising small fixed boiling-range pseudo-components for describing yields of said reaction product;ii) a plurality of basic lumps comprising larger fixed boiling-range pseudo-components each comprising (groupings of said plurality of product lumps for describing feed conversion and selectivity, and wherein the number of lumps in said plurality of basic lumps is less than the number of lumps in said plurality of product lumps;(b) defining a conversion reaction network for said plurality of basic lumps, wherein reaction paths in said conversion reaction network flow from heavier to lighter components;(c) constructing a first plurality of chemical kinetic cracking equations in terms of said plurality of basic lumps for each step in said conversion reaction network based on a generalized equation for change in concentration for each of said plurality of basic lumps, and wherein said generalized equation integrates catalyst decay with chemical kinetics;(d) constructing a second plurality of chemical kinetic cracking equations in terms of said plurality of product lumps for each step in said conversion reaction network based on said generalized equation for change in concentration for each of said plurality of product lumps and for distribution of each of said plurality of basic lumps into the product lumps corresponding to each of said plurality of basic lumps; wherein said second plurality of chemical kinetic cracking equations are dependent on the basic lump concentrations determined using said first plurality of chemical kinetic cracking equations; and(e) wherein the combination of said first and second plurality of chemical kinetic cracking equations comprise a kinetic model for the riser reactor cracking of said multiplicity of complex hydrocarbon molecules.