CN101980230A - Catalytic cracking reaction system process simulation optimization model and solution method thereof - Google Patents

Abstract

The invention relates to a catalytic cracking reaction system process simulation optimization model and a solution method thereof. A novel model is a model based on Gupta and the like; in order to contribute to solving the model in process simulation software such as AspenPlusTM, a new form is provided for part of expressions in a material balance equation, an energy balance equation and a fluidized state computation model; and components or stream physical property calculation subprograms provided by the process simulation software are called in the model solution process, so that the simulation optimization work of the model is finished by the process simulation software, the model is convenient to apply to engineering and the calculation result is accurate.

Description

Catalytic-cracking reaction system process simulation Optimization Model and method for solving thereof

Technical field

The present invention relates to petrochemical process simulation and optimisation technique, relate in particular to catalytic-cracking reaction system simulative optimization model and method for solving thereof.

Background technology

Catalytic cracking as the crude oil secondary processing means of the present treatment capacity maximum of China occupies extremely important status in petroleum refining industry, the quality of catalytic cracking unit design and operation directly has influence on the overall efficiency of refinery.In the design and the operational phase of catalytic cracking unit, by catalytic-cracking reaction system process simulation Optimization Model, necessary simulative optimization is carried out in design and operation to its reactive system, can improve whole Design of device and operant level, and then increases the economic benefit of refinery.

The basis of catalytic-cracking reaction system process simulation and optimization is to need an accurately practical process calculation model.The application of existing process calculation model in design of catalytic-cracking reaction system process and operation both at home and abroad is as the catalytic unit simulative optimization software FCCLK of Luoyang Petrochemical Engineering Co., China Petrochemical Group Corp ^TM, the catalytic unit simulative optimization software Aspen FCC of U.S. ASPENTECH company ^TMDeng.The successful Application of these process calculation model and software package has important promote significance for the design and the operation optimization of catalytic cracking unit, but has following shortcoming:

1 these process calculation model are at concrete catalytically cracked stock (base stocks) and exploitation, for the bigger feedstock oil of basic material oil nature gap, the situation that the analog result accuracy descends can appear calculating.

2 because concrete catalytic cracking unit reactive system varies, and therefore for guaranteeing to calculate the accuracy of simulation, these process calculation model all are provided with a large amount of device factors on stream, causes its concrete inconvenience of using.

3 for calculating analog result, and these process calculation model can provide the essential informations such as variation of pressure, temperature, product yield, but can not provide voidage, the gas-solid slippage factor etc. process design and operation to be had the information of important references meaning.

4 relate in the selection of species at catalytic-cracking reaction system, these process calculation model all adopt the lumped reaction model, be about to raw material and product people for being divided into a plurality of lumped components, and the variation of these lumped component flows and composition be considered as the variation of raw material and product flow and composition.But at present process simulation and Optimization Software relate to that species are generally real component or virtual group is graded.Therefore, adopt the lumped reaction model in catalytic-cracking reaction system simulation and Optimization Model, it is integrated to cause it to be difficult to process simulation and Optimization Software, and then is difficult to carry out the problem of total system simulative optimization.

Summary of the invention

Technical scheme of the present invention is as follows:

A kind of catalytic-cracking reaction system simulative optimization model, based on [Gupta et al.A new generic approach for the modeling of fluid catalytic cracking (FCC) riser reactor.Chemical Engineering Science such as Gupta, 2007,62:4510-4528.] the catalytic-cracking reaction system process calculation model that proposes, for the benefit of the Calculation of Physical Properties subroutine that provides of coupling process simulation softward is calculated the related rerum natura of Model Calculation, at the mass balance equation, the part expression formula proposes new form in energy balance equation and the gas-solid fluidized state model, therefore model can be used as the subscriber unit model of process simulation software, thereby finishes the simulation and the optimization work of catalytic cracking unit in process simulation software.

Below the present invention is further illustrated, specific as follows:

1 mass balance equation mathematics expression-form is implemented as follows:

To the non-participation component of cracking reaction i,

f _i，j＝f _i，j-1

The cracking in vapour phase reaction is participated in component i,

$f_{i,j}=f_{i,j-1}+M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{r}}_{m,i,n,j}{f}_{\mathrm{cat},j}{\mathrm{\τ}}_{\mathrm{cat},j}\right)}_{M_m\≥M_i+M_n,M_i\≥M_n}$

$+M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{r}}_{m,n,i,j}{f}_{\mathrm{cat},j}{\mathrm{\τ}}_{\mathrm{cat},j}\right)}_{M_m\≥M_n+M_i,M_n\≥M_i}-M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\τ}}_{\mathrm{cat},j}\right)}_{M_i\≥M_m+M_n,M_m\≥M_n}$

To the solid phase components coke,

$f_{\mathrm{coke},j}=f_{\mathrm{coke},j-1}+{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\underset{m=1}{\overset{N}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\τ}}_{\mathrm{cat},j}(M_i-M_m-M_n)\right)}_{M_i\≥M_m+M_n,M_m\≥M_n}$

The former form of this equation is referring to document-Gupta et al.Chemical Engineering Science, and 2007, formula among the 62:4510-4528.-(9) and formula (11):

To the non-participation component of cracking reaction i,

f _i，j＝f _i，j-1

The cracking in vapour phase reaction is participated in component i,

To the solid phase components coke,

Wherein i, m and n are the code name of component; M is for participating in the relative molecular mass of reactive component, kg/kmol; The import of j-1 representative reaction infinitesimal; The outlet of j representative reaction infinitesimal; Cat represents Cracking catalyst; Coke represents coke; F is a mass rate, kg/s; N is the component sum; Be reaction rate, kmol/ (kg (cat) s); τ represents Cracking catalyst residence time in the reaction infinitesimal, s.

2 for the energy balance equation, is implemented as follows:

The mathematical expression general type 1 of energy balance equation,

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\∫}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\∫}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

$-(\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\∫}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\∫}}{c}_{p,\mathrm{coke}}\mathrm{dT})-\mathrm{\α\πd\Δl}(T_{j-1}-T_{\mathrm{env}})$

The general type 2 of the mathematical expression of energy balance equation,

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\∫}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\∫}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

$-(\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\∫}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\∫}}{c}_{p,\mathrm{coke}}\mathrm{dT})-\mathrm{\α\πd\Δl}(T_j-T_{\mathrm{env}})$

If the assumed response system is the adiabatic reaction system, two formulas that then go up become,

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\∫}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\∫}}{c}_{p,\mathrm{coke}}\mathrm{dT})-(\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\∫}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\∫}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

Wherein,

h _j-1＝h _j-1(T _j-1，p _j-1，z _j-1)

h _j＝h _j(T _j，p _j，z _j)

The former form of this equation is referring to document-Gupta et al.Chemical Engineering Science, and 2007, formula among the 62:4510-4528.-(16):

$(f_{\mathrm{cat}}{c}_{p,\mathrm{cat}}+f_{\mathrm{coke},j-1}{c}_{p,\mathrm{coke}}+\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_{i,j-1}{c}_{p,i})\left(T_{j-1}{T}_j\right)=\underset{i}{\mathrm{\Σ}}\underset{m}{\mathrm{\Σ}}\underset{n}{\mathrm{\Σ}}\left({\stackrel{\‾}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\τ}}_{\mathrm{cat},j}{\mathrm{\ΔH}}_{i,m,n,j}\right)$

α is a reactor wall overall heat transfer coefficient, kW/ (m ²K); π is a circular constant; D is the reactive system diameter, m; Δ l is reaction infinitesimal height, m; T _EnvBe environment temperature, K; T _RefFor the component thermodynamic state is calculated reference temperature, K; H is a specific enthalpy, kJ/kg; c _pBe constant pressure specific heat, kJ/ (kg K); T is the cracking reaction temperature, K; Δ H is a cracking reaction heat, kJ/kmol.H is the function of local temperature, pressure and composition, the Calculation of Physical Properties subroutine that the calculating invoked procedure simulation softward of this variable provides.

3 for gas-solid fluidized state computation model, be implemented as follows,

For related gas phase velocity accounting equation, solid phase speed calculation equation and gaseous viscosity accounting equation (Gupta et al model hypothesis gaseous viscosity is a constant) according to following formula:

$u_g=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{f}_i}{{\mathrm{A\ρ}}_g{\mathrm{\δ}}_g}$

ρ _g＝ρ _g(T，p，z)

$u_{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HDA0000030709310000011.png,HDA0000030709310000021.png"\; state="\{\{state\}\}">c</figure-callout>}1}=\frac{f_{\mathrm{cat}}+f_{\mathrm{coke}}}{{\mathrm{A\&rho;}}_{c1}(1-{\mathrm{\&delta;}}_g)}$

ρ _c1＝(ρ _cat(1-y _coke)+ρ _cokey _coke)(1-δ _g)

μ _g＝μ _g(T，p，z)

Solid phase speed calculation equation, the former form of gas phase velocity accounting equation be referring to document-Gupta et al.Chemical Engineering Science, and 2007, formula among the 62:4510-4528.-(26) and (38):

$u_{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HDA0000030709310000011.png,HDA0000030709310000021.png"\; state="\{\{state\}\}">c</figure-callout>}1}\&ap;\frac{f_{\mathrm{cat}}}{{\mathrm{A\&rho;}}_{\mathrm{cat}}(1-{\mathrm{\&delta;}}_g)}$

$u_g=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_i}{{\mathrm{A\&rho;}}_g{\mathrm{\&delta;}}_g}$

${\mathrm{\&rho;}}_g=\frac{P\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{f_i}{M_i}}{\mathrm{RT}}$

Wherein c1 represents catalyzer bunch group; G represents gas phase; U is a speed, m/s; ρ is a density, kg/m ³μ is a viscosity, Pas; A is long-pending for riser partial cross section, m ²δ is a volumetric fraction; Z is that local gas phase mole is formed; Y is local massfraction; R is a universal gas constant, 8.3145J/ (mol K); P is a local pressure, Pa.ρ _gWith μ _gBe the function of local temperature, pressure and composition, this variable is provided by the Calculation of Physical Properties subroutine that needs the invoked procedure simulation softward to provide.

The method for solving of 4 catalytic-cracking reaction system simulative optimization models, specific implementation method: catalytic-cracking reaction system is divided into a large amount of stratiform reaction infinitesimals, flow composition, temperature and the pressure that a strand composition, temperature and calculation of pressure obtain reacting infinitesimal outlet vapor phase stream thigh or solid phase stream thigh according to vapor phase stream thigh that reacts the infinitesimal import or solid phase, the Calculation of Physical Properties subroutine computation model that while invoked procedure simulation softward provides is found the solution a required component or a stream burst rerum natura.

Utilize computer advanced language FORTRAN to write AspenPlus ^TMUser model subroutine USER2 utilizes AspenPlus then ^TMThe compiling link environment AspenPlusSimulationEngine that software provides ^TMIt is carried out compiling link, generate the .DLL file, then at AspenPlus ^TMIn call this .DLL file and realize this model and AspenPlus ^TMSoftware fully-integrated, thus AspenPlus can be utilized ^TMSoftware virtual component characterization system, component physical parameter database, Calculation of Physical Properties system and Calculation of Physical Properties model bank; AspenPlus is passed through in calculating for component such as gas phase specific enthalpy, density of gas phase or stream burst rerum natura ^TMThe calling of Calculation of Physical Properties subroutine that software provides realized.

The invention has the beneficial effects as follows: new model has adopted real component and virtual component reaction kinetics, be convenient to a component or a stream burst Calculation of Physical Properties subroutine that the invoked procedure simulation softward provides, so catalytic-cracking reaction system simulative optimization model of the present invention and method for solving other models mentioned in the background technology above and the general shortcoming of solver have effectively been avoided.

Description of drawings

Fig. 1 illustrates the real component that catalytic-cracking reaction system simulative optimization model relates to or the description illustration intention of virtual component cracking reaction network.

Fig. 2 is the synoptic diagram that the general finite element method of finding the solution catalytic-cracking reaction system simulation and Optimization Model employing is shown.

Fig. 3 is the description illustration intention that real component of catalytic-cracking reaction system outlet reacting final product and virtual component composition result of calculation are shown.

Fig. 4 is the description illustration intention that reactive system unit temp variation tendency result of calculation is shown.

Fig. 5 is the description illustration intention that reactive system device pressure trend result of calculation is shown.

Fig. 6 is the description illustration intention that reactive system device voidage variation tendency result of calculation is shown.

Fig. 7 is the description illustration intention that reactive system device gas-solid rate variation trend result of calculation is shown.

Embodiment

The present invention is described in further detail in conjunction with the accompanying drawings:

The environment of finding the solution of catalytic-cracking reaction system simulative optimization model of the present invention is AspenPlus ^TMProcess simulation software is if other softwares provide required user model DLL (dynamic link library) to adopt.

Fig. 1 is real component or virtual component cracking reaction network, and the phylogenetic reaction of assumed response is cracking reaction, and the component i cracking reaction of a unit generates the component m of a unit and the component n of a unit.The cracking reaction kinetic model that relates in the solution procedure adopts [Gupta et al.A new generic approach for the modeling of fluid catalytic cracking (FCC) riser reactor.Chemical Engineering Science such as Gupta, 2007,62:4510-4528.] correlation model that provides.

For the mass balance equation, calculate according to following formula:

To the non-participation component of cracking reaction i,

f _i，j＝f _i，j-1

The cracking in vapour phase reaction is participated in component i,

$f_{i,j}=f_{i,j-1}+M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{m,i,n,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}\right)}_{M_m\&GreaterEqual;M_i+M_n,M_i\&GreaterEqual;M_n}$

$+M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{m,n,i,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}\right)}_{M_m\&GreaterEqual;M_n+M_i,M_n\&GreaterEqual;M_i}-M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}\right)}_{M_i\&GreaterEqual;M_m+M_n,M_m\&GreaterEqual;M_n}$

To the solid phase components coke,

$f_{\mathrm{coke},j}=f_{\mathrm{coke},j-1}+{\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}(M_i-M_m-M_n)\right)}_{M_i\&GreaterEqual;M_m+M_n,M_m\&GreaterEqual;M_n}$

Wherein i, m and n are the code name of component; M is for participating in the relative molecular mass of reactive component, kg/kmol; The import of j-1 representative reaction infinitesimal; The outlet of j representative reaction infinitesimal; Cat represents Cracking catalyst; Coke represents coke; F is a mass rate, kg/s; N is the component sum; Be reaction rate, kmol/ (kg (cat) s); τ represents Cracking catalyst residence time in the reaction infinitesimal, s.

For the energy balance equation, considered effective insulation because of simulateding in the unit engineering design, so assumed response device thermal insulation (being α=0) has adopted following formula to calculate:

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})-(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

h _j-1＝h _j-1(T _j-1，p _j-1，z _j-1)

h _j＝h _j(T _j，p _j，z _j)

Wherein h is a specific enthalpy, kJ/kg; c _pBe constant pressure specific heat, kJ/ (kg K); T is the cracking reaction temperature, K; T _RefFor the component thermodynamic state is calculated reference temperature, K.H is the function of local temperature, pressure and composition, and AspenPlus is called in the calculating of this variable ^TMThe Calculation of Physical Properties subroutine that process simulation software provides.

For the calculating of the related gas phase velocity of fluidized state computation model, solid phase speed and gaseous viscosity, the following formula of foundation:

$u_g=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_i}{{\mathrm{A\&rho;}}_g{\mathrm{\&delta;}}_g}$

ρ _g＝ρ _g(T，p，z)

$u_{c1}=\frac{f_{\mathrm{cat}}+f_{\mathrm{coke}}}{{\mathrm{A\&rho;}}_{c1}(1-{\mathrm{\&delta;}}_g)}$

ρ _c1＝(ρ _cat(1-y _coke)+ρ _cokey _coke)(1-δ _g)

μ _g＝μ _g(T，p，z)

Wherein c1 represents catalyzer bunch group; G represents gas phase; U is a speed, m/s; ρ is a density, kg/m ³μ is a viscosity, Pas; A is long-pending for riser partial cross section, m ²δ is a volumetric fraction; Z is that local gas phase mole is formed; Y is local massfraction.ρ _gWith μ _gBe the function of local temperature, pressure and composition, this variable calculates need call AspenPlus ^TMThe Calculation of Physical Properties subroutine that process simulation software provides.

The general finite element method (seeing accompanying drawing 2) that Fig. 2 adopts for this model solution, its ultimate principle is for being divided into catalytic-cracking reaction system a large amount of stratiform reaction infinitesimals, obtain reacting composition, temperature and the pressure that infinitesimal exports vapor phase stream thigh or solid phase stream thigh according to the vapor phase stream thigh that reacts the infinitesimal import or a solid phase stream strand composition, temperature and calculation of pressure, call AspenPlus simultaneously ^TMThe Calculation of Physical Properties subroutine that software provides is calculated component or stream burst rerum natura.

Utilize computer advanced language FORTRAN to write AspenPlus ^TMUser model subroutine USER2 utilizes AspenPlus then ^TMThe compiling link environment AspenPlusSimulationEngine that software provides ^TMIt is carried out compiling link (concrete grammar please refer to software and helps explanation), generate the .DLL file, then at AspenPlus ^TMIn call this .DLL file and realize this model and AspenPlus ^TMSoftware fully-integrated, thus AspenPlus can be utilized ^TMSoftware virtual component characterization system, component physical parameter database, Calculation of Physical Properties system and Calculation of Physical Properties model bank.AspenPlus is passed through in calculating for component such as gas phase specific enthalpy, density of gas phase or stream burst rerum natura ^TMThe calling of Calculation of Physical Properties subroutine that software provides realizes that concrete calling program and interface regulation help explanation with reference to this software.

Table 1 is a catalytic-cracking reaction system simulative optimization model input raw material properties, and table 2 is the input operation condition of simulative optimization model.Utilize the input data of table 1 and table 2, adopt AspenPlus ^TMSoftware is found the solution model, and Fig. 3-Fig. 7 is the analog computation result of this catalytic-cracking reaction system simulative optimization model under table 1 and table 2 condition.

Fig. 3 is for going out reactive system end-product component accumulative total liquid phase volume, owing to finding the solution at AspenPlus of this model ^TMSoftware is finished, and can use AspenPlus at industrial data ^TMThe parameter estimation function of software is estimated model parameter, guarantees that its analog computation result is consistent with industrial data, and can carry out appropriate extension to it according to the model parameter that estimation obtains, and shows the dirigibility of this model on the prediction product yield.Fig. 4 is the stream thigh temperature changing trend result of calculation that the reactive system device, as can be seen, because the existence of heat absorption cracking reaction, the reactive system temperature descends rapidly and maintains about 500 ℃, its result of calculation and industrial observed data (be reactive system work off one's feeling vent one's spleen solid-state temperature 500 ℃) are consistent, have shown that this model is for reactive system axial temperature accuracy for predicting.Fig. 5 falls the variation synoptic diagram for the reactive system axle pressure, and as can be seen, pressure falls and is approximately 32kPa, this result and industrial observed data 30.5kPa basically identical.Fig. 6 is the changing trend diagram of reactive system axial air gap rate, and as can be seen, reactive system axial air gap rate rises rapidly, and maintains 0.95m ³/ m ³About, this value and the general value of fluidization document conclusion 0.8～0.98m ³/ m ³Consistent.Fig. 7 is the changing trend diagram of the axial gas-solid phase of reactive system speed, as can be seen, gas-solid two-phase speed all continues to rise, gas phase velocity finally maintains 8m/s, solid phase speed maintains 2m/s, the gas-solid slippage factor maintains about 4, and the gas-solid slippage factor that this and fluidization pertinent literature provide is approximately 4.3 conclusion and coincide, and has further proved the accuracy of this model for gas-solid phase rate calculations.

The input feedstock property of table 1 catalytic-cracking reaction system simulative optimization model

Table 2 catalytic-cracking reaction system simulative optimization model basis initial conditions

Open catalytic-cracking reaction system simulative optimization model of the present invention and method for solving, those skilled in the art can be by using for reference this paper content, and links such as appropriate change model formation, method for solving realize.The present invention is described by concrete embodiment, and person skilled obviously can be changed or suitably change and combination system as herein described in not breaking away from content of the present invention, spirit and scope, realizes the technology of the present invention.The replacement that all are similar and change apparent to those skilled in the artly, they are regarded as being included in spirit of the present invention, scope and the content.

Claims (2)

1. catalytic-cracking reaction system simulative optimization model, it is characterized in that, catalytic-cracking reaction system process calculation model [Gupta et al.A new generic approach for the modeling of fluid catalytic cracking (FCC) riser reactor.Chemical Engineering Science based on propositions such as Gupta, 2007,62:4510-4528.], for ease of this model at universal process simulative optimization software such as AspenPlus ^TMIn find the solution, the mathematical expression form of material balance equation, energy balance equation and fluidized state computation model part expression formula is proposed;

Mass balance equation mathematics expression-form:

To the non-participation component of cracking reaction i,

f _i，j＝f _i，j-1

The cracking in vapour phase reaction is participated in component i,

$f_{i,j}=f_{i,j-1}+M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{m,i,n,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}\right)}_{M_m\&GreaterEqual;M_i+M_n,M_i\&GreaterEqual;M_n}$

$+M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{m,n,i,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}\right)}_{M_m\&GreaterEqual;M_n+M_i,M_n\&GreaterEqual;M_i}-M_i{\left(\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}\right)}_{M_i\&GreaterEqual;M_m+M_n,M_m\&GreaterEqual;M_n}$

To the solid phase components coke,

$f_{\mathrm{coke},j}=f_{\mathrm{coke},j-1}+{\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{r}}_{i,m,n,j}{f}_{\mathrm{cat},j}{\mathrm{\&tau;}}_{\mathrm{cat},j}(M_i-M_m-M_n)\right)}_{M_i\&GreaterEqual;M_m+M_n,M_m\&GreaterEqual;M_n}$

Wherein i, m and n are the code name of component; M is for participating in the relative molecular mass of reactive component, kg/kmol; The import of j-1 representative reaction infinitesimal; The outlet of j representative reaction infinitesimal; Cat represents Cracking catalyst; Coke represents coke; F is a mass rate, kg/s; N is the component sum;

Be reaction rate, kmol/ (kg (cat) s); τ represents Cracking catalyst residence time in the reaction infinitesimal, s;

Energy balance equation mathematics expression-form:

Energy balance equation mathematical expression general type 1:

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

$-(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})-\mathrm{\&alpha;\&pi;d\&Delta;l}(T_{j-1}-T_{\mathrm{env}})$

The general type 2 of energy balance equation mathematical expression:

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

$-(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})-\mathrm{\&alpha;\&pi;d\&Delta;l}(T_j-T_{\mathrm{env}})$

If the assumed response system is the adiabatic reaction system, two formulas that then go up become:

$0=(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j-1}\right)h_{j-1}+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j-1}\underset{T_{\mathrm{ref}}}{\overset{T_{j-1}}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})-(\left(\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_{i,j}\right)h_j+f_{\mathrm{cat}}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{cat}}\mathrm{dT}+f_{\mathrm{coke},j}\underset{T_{\mathrm{ref}}}{\overset{T_j}{\&Integral;}}{c}_{p,\mathrm{coke}}\mathrm{dT})$

Wherein,

h _j-1＝h _j-1(T _j-1，p _j-1，z _j-1)

h _j＝h _j(T _j，p _j，z _j)

α is a reactor wall overall heat transfer coefficient, kW/ (m ²K); π is a circular constant; D is the reactive system diameter, m; Δ l is reaction infinitesimal height, m; T _EnvBe environment temperature, K; T _RefFor the component thermodynamic state is calculated reference temperature, K; H is a specific enthalpy, kJ/kg; c _pBe constant pressure specific heat, kJ/ (kg K); T is the cracking reaction temperature, K.H is the function of local temperature, pressure and composition, the Calculation of Physical Properties subroutine that the calculating invoke user of this variable or commercial process simulation softward provide.

For the gas phase velocity in the gas-solid fluidized state computation model, solid phase speed and gaseous viscosity according to following formula:

$u_g=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{f}_i}{{\mathrm{A\&rho;}}_g{\mathrm{\&delta;}}_g}$

$u_{c1}=\frac{f_{\mathrm{cat}}+f_{\mathrm{coke}}}{{\mathrm{A\&rho;}}_{c1}(1-{\mathrm{\&delta;}}_g)}$

μ _g＝μ _g(T，p，z)

ρ _c1＝(ρ _cat(1-y _coke)+ρ _cokey _coke)(1-δ _g)

ρ _g＝ρ _g(T，p，z)

Wherein c1 represents catalyzer bunch group; G represents gas phase; U is a speed, m/s; ρ is a density, kg/m ³μ is a viscosity, Pas; A is long-pending for riser partial cross section, m ²δ is a volumetric fraction; Z is that local gas phase mole is formed; Y is local massfraction; P is a local pressure, Pa.ρ _gWith μ _gBe the function of local temperature, pressure and composition, this variable is provided by the Calculation of Physical Properties subroutine that needs invoke user or commercial process simulation softward to provide.

2. according to the method for solving of the catalytic-cracking reaction system simulative optimization model of claim 1, it is characterized in that catalytic-cracking reaction system is divided into a large amount of stratiform reaction infinitesimals, flow composition, temperature and the pressure that a strand composition, temperature and calculation of pressure obtain reacting infinitesimal outlet vapor phase stream thigh or solid phase stream thigh according to vapor phase stream thigh that reacts the infinitesimal import or solid phase, the Calculation of Physical Properties subroutine computation model that while invoked procedure simulation softward provides is found the solution a required component or a stream burst rerum natura.

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