US 6,212,488 B1Granted

Riser reactor simulation in catalytic cracking

AssigneePhillips Petroleum Company

InventorsPaul F. Meier, Dhananjay B. Ghonasgi, Michael David Wardinsky

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Abstract

A predictive kinetic model is disclosed for simulating fluid catalytic cracking of large hydrocarbon molecules having a lumping scheme that includes hydrocarbon descriptions based on boiling point distribution and chemical properties. The simulation results in a nearly continuous prediction of products as function of boiling point temperature. The lumping scheme defines a relatively large number of small fixed boiling-point range pseudo-components for describing product material, and a smaller number of larger boiling-point range pseudo-components for describing feed conversion and selectivity. The chemical properties for describing hydrocarbons include total hydrogen, aromatic carbon and aromatic hydrogen.

Claims21

Dependent claims

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.

6 more elements

A computer implemented method for simulating 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) providing said computer with a kinetic model for simulating said cracking reaction, said kinetic model including at least;
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;
(iii) a conversion reaction network for said plurality of basic lumps, wherein reaction paths in said conversion reaction network flow from heavier to lighter components;
(iv) a first plurality of chemical kinetic cracking equations in terms of said plurality of basic lumps for each step in said 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;
(v) 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;
(b) providing said computer with initial data including at least:
feed characteristics, catalyst characteristics, and reactor conditions;
(c) repeatedly calculating values for the following conditions according to said kinetic model:
i) said reaction rate constants at riser reactor temperature;
ii) fractional conversion of the feed;
iii) distribution of said product lumps within said basic lumps;
and
iv) yields of lower molecular weight products;
and
(d) displaying the distribution of cracked products in terms of boiling point temperature.

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Apparatus for simulating 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, said apparatus comprising;

a computer programmed to perform method steps comprising:
(a) storing a kinetic model in said computer for simulating said cracking reaction, said kinetic model including at least;
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;
(iii) a conversion reaction network for said plurality of basic lumps, wherein reaction paths in said conversion reaction network flow from heavier to lighter components;
(iv) a first plurality of chemical kinetic cracking equations in terms of said plurality of basic lumps for each step in said 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;
(v) 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;
(b) providing said computer with initial data including at least:
feed characteristics, catalyst characteristics, and reactor conditions;
(c) repeatedly calculating values for the following conditions according to said kinetic model:
i) said reaction rate constants at riser reactor temperature;
ii) fractional conversion of the feed;
iii) distribution of said product lumps within said basic lumps;
and
iv) yields of lower molecular weight products;
and
(d) displaying the distribution of cracked products in terms of boiling point temperature.

16 more elements

A program storage device, readable by a computer, tangibly embodying a program of instructions executable by said computer to perform method steps for simulating 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 steps comprising;

(a) storing a kinetic model in said computer for simulating said cracking reaction, said kinetic model including at least;
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;
(iii) a conversion reaction network for said plurality of basic lumps, wherein reaction paths in said conversion reaction network flow from heavier to lighter components;
(iv) a first plurality of chemical kinetic cracking equations in terms of said plurality of basic lumps for each step in said 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;
(v) 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 chance 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;
(b) repeatedly calculating values for the following conditions according to said kinetic model:
i) said reaction rate constants at riser reactor temperature;
ii) fractional conversion of the feed;
iii) distribution of said product lumps within said basic lumps;
iv) yields of lower molecular weight products;
and
(c) displaying the distribution of cracked products in terms of boiling point temperature.

12 more elements

Dependencies are inferred from the claim text.

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Abstract

(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.

6 more elements