CN103914430A - Multiple fluid phase mixed system chemical equilibrium calculating system - Google Patents

Abstract

The invention relates to a multiple fluid phase mixed system chemical equilibrium calculating system. The calculating system comprises a data input module, a multiple mixed system chemical equilibrium calculating module, a system thermodynamic property calculating module and a calculating result output module; when the influence caused by the structures and shapes of particles are not needed to consider, the amount of parent materials of various reaction and generation species and the reference state mole Gibbs free energy are known, the minimal value of the Gibbs free energy of the whole mixed system can be calculated by gradually planning an optimization algorithm at the second time by calculating the Gibbs free energy of the system and the activity coefficients of various species and the amount {Xi} of the multiple chemical equilibrium state substances of various reactants and products through a thermodynamic model, so as to calculate the property of the equilibrium state of the mixed system; the calculating system does not need to perform experience trying when the chemical equilibrium is calculated, and a plurality of mixed system thermodynamic properties including the concentrations, activity, and activity coefficients and the like of all reactants and products can be high-efficiently and quickly calculated in the multiple chemical equilibrium by the optimized procedure and algorithm.

Description

A kind of fluid-phase mixed system multi-chemical Equilibrium computing system

Technical field

The present invention relates to a kind of polycomponent comprises mixed gas, electrolyte solution, little molecular mixing solution, large molecule lean solution fluid-phase mixed system multi-chemical Equilibrium computing system containing multi-chemical Equilibrium mixed system.

Background technology

In chemical process, to the mixed system containing chemical reaction, under the conditions such as given initial concentration and proportioning, temperature, pressure, need to ask and calculate each material balance concentration isoequilibrium related physical quantity, and the series of heat such as activity, the thermodynamic function mechanical property of each material.This estimation product transform with the efficiency separating, improve equipment automatically very important aspect control with technological design, chemical process.But actual mixed system often relates to multiple components, contains multiple chemical reactions, the composition of solution and complex structure, computation process is very difficult.

Tradition empirical method can be carried out simple EQUILIBRIUM CALCULATION FOR PROCESS, to single chemical equilibrium, as shown in formula (1-3), utilizes equilibrium constant K can ask the equilibrium concentration that calculates each material.

DD+eE+... → gG+hH+... or be abbreviated as Σ v _ib _i=0

(1)

$\mathrm{\ΔG}=\mathrm{\Σ}{v}_i{G}_{i,m}=\mathrm{\Σ}{v}_i{G}_{i,m}^0+\mathrm{\Σ}{v}_i\mathrm{RT}\ln a_i=\mathrm{\Σ}{v}_i{G}_{i,m}^0+\mathrm{RT}\ln K=0$

(2)

$K=\∏a_i^{v_i}=\∏(x_i^{v_i}\·f_i^{v_i})$

(3)

In above formula, Δ G, R, T, G _im, v _i, , x _i, f _i, a _ibe respectively reaction Gibbs free energy, gas law constant, thermodynamic temperature, reaction stoichiometric coefficient, mole Gibbs free energy of component or species, standard mole Gibbs free energy, the amount of substance concentration of component or species, take amount of substance as basic activity coefficient and activity.By formula (1-3), if known response Gibbs can become Δ G or equilibrium constant K.First attempt determining the concentration of component according to reactant and product proportionate relationship, then obtain corresponding activity coefficient f according to thermodynamical model (as Debye – H ü ckel, Pitzer model etc.) by concentration of component _i, by activity product compare with equilibrium constant K, if inconsistent, then adjust concentration of component, until activity product equates with the equilibrium constant.

This traditional empirical method can only be calculated one or a few chemical equilibrium, low to multi-chemical Equilibrium counting yield, can not solve a difficult problem for large-scale calculations.For example to calculate H under finite concentration ₃pO ₄-NaH ₂pO ₄when the pH value of buffer solution, very large difficulty will be run into.The number of special mixed system chemical equilibrium becomes numerous, and it is very huge that component becomes, and above-mentioned traditional computing method can get into enormous difficulties, and its result of calculation is also undesirable.

Summary of the invention

The object of the invention is to overcome the defect that prior art exists, one fluid-phase mixed system multi-chemical Equilibrium computing system is fast and efficiently provided, accurately calculates equilibrium concentration, balance related physical quantity and the series of heat mechanical property of each material in mixed system.

The technical scheme of the object of the invention is: a kind of fluid-phase mixed system multi-chemical Equilibrium computing system, described whole computing system comprises data input, calculate initialization, mixed system Gibbs minimization of free energy calculates, mixed system series balance character is calculated, five modules of result of calculation output and preservation; To the common fluid-phase mixed system of several classes, when without considering that the structure of species and shape bring while affecting, the amount { X of the parent material of known each species _iand reference state mole Gibbs free energy , change { X _itime, the calculating of the Gibbs free energy by corresponding thermodynamical model to system, each species activity coefficient and activity coefficient, calculate the Gibbs free energy minimization value of whole mixed system by quadratic programming optimization algorithm (SQP) progressively, now obtain the amount of substance { X of each reactant and product under multi-chemical Equilibrium state _i, further counting system series balance state behavior thus.

Technique scheme, described computing system composition and calculation process are:

1) described data input, is by the title { L of the each component of mixed system _jand content { N _{θ j}, according to reaction Σ θ _ij.L _j=S _igenerate the title { S of each species _i, stoichiometric coefficient { θ _ij, reference state Gibbs free energy , temperature conditions T, mixed system type, and attached can growth data and tables of data.

2) described calculating initialization is the amount of substance { L according to each component _jdetermine each species { S _ithe amount { X of parent material _i; Determine mixed system and select appropriate thermodynamical model according to the type of mixed system, mixed system comprises gaseous mixture, electrolyte mixed solution, little molecular mixing system, large molecule lean solution system;

3) described mixed system Gibbs minimization of free energy calculates, and is the objective function first arranging in the Gibbs minimization of free energy process of mixed system $g=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+g^{\mathrm{id},\mathrm{mix}}+g^{\mathrm{ex}}=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln x_i+\mathrm{\Σ}{X}_i\mathrm{RT}\ln f_i,$ The gradient function of objective function function , and constraint condition then thermodynamical model calculates the activity coefficient f of each species _iand further calculate the gradient function of above-mentioned objective function and objective function, and then call donlp2 or SNOPT optimum procedure, complete Gibbs free energy minimization value based on quadratic programming optimization algorithm progressively and calculate, return to objective function extreme point, i.e. the minimum value g of mixed system Gibbs free energy _minand g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...);

4) described mixed system series balance character is calculated, and is the extreme point returning by mixed system Gibbs minimization of free energy computing module, i.e. g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...) and calculate the concentration x of each species _i, calculate the activity a of each species based on thermodynamical model _i, activity coefficient f _iand the activity a of each component _jand activity coefficient f _j, calculate the equilibrium constant { K that generates each species _iwith react Gibbs free energy change ; In order to guarantee the reliability of result of calculation, utilize checking activity a _iwith activity coefficient f _irationality, utilize $\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln a_i=\mathrm{\Σ}{N}_{\mathrm{\θj}}{\mathrm{\ϵ}}_j^0+\mathrm{\Σ}{N}_{\mathrm{\θj}}\mathrm{RT}\ln a_j$ Checking activity a _jwith activity coefficient f _jrationality, utilize checking equilibrium constant lnK _i=lna _i-Σ θ _ijlna _jcalculate rationality, utilize $\mathrm{\Δ}{G}_{i,m}^0={\mathrm{\ϵ}}_i^0-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}{\mathrm{\ϵ}}_j^0$ Confirmatory reaction process Gibbs free energy change $\mathrm{\Δ}{G}_{i,m}^0=-(\mathrm{RT}\ln a_i-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}\mathrm{RT}\ln a_j)$ Rationality;

5) described result of calculation output, is to described mixed system series balance character computing module result of calculation, and mixed system series balance character is calculated and exported and preserve.

Technique scheme, described computing system is without considering microgranular texture and shape in mixed system and the impact bringing thereof, the type of described mixed system comprises:

(1) gaseous mixture system, applied heat mechanical model is Chemical Reaction Model, the thermodynamical model that can expand selection has carat-amber dragon equation, van der Waals equation;

(2) comprise electrolyte solution system, applied heat mechanical model is Chemical Reaction Model, and the thermodynamical model that can expand selection has Debye – H ü ckel, Pitzer;

(3) comprise little molecular solution system, applied heat mechanical model is Chemical Reaction Model, and the thermodynamical model that can expand selection has NRTL, Wilson, UNIFAC;

(4) comprise large molecule lean solution system, applied heat mechanical model is Chemical Reaction Model, and the thermodynamical model that can expand selection has UNIFAC.

Technique scheme, described computing system determines that the component of mixed system and the method for species are: all regard every kind of molecule in mixed system or ion particulate as species { S _i; From species, select independent, basic species as reactant, obtain by certain stoichiometric coefficient reaction if arbitrary species all can be regarded as by these reactants, these reactants are as the component { L of mixed system _j.

Technique scheme is called outside optimum procedure and calculates the minimum value g of the Gibbs free energy of mixed system in described mixed system Gibbs minimization of free energy computation process _min, and be in g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...), described outside optimum procedure is donlp2 or SNOPT program, based on the minimum value of Novel Algorithm (SQP) calculating target function progressively.

Adopt technique scheme to there is following technical advantage:

(1) computing system of the present invention and method can be without carrying out experience trial in the time of chemistry balance, can respectively react efficiently, fast and generate the concentration of species under multi-chemical Equilibrium state, multiple mixed system macroscopic properties such as activity, activity coefficient by optimum procedure and algorithm;

(2) technical solution of the present invention can solve extensive polycomponent multiple chemical molecular balance problem, applicable to gaseous mixture, electrolyte solution, little molecular mixing solution, and the large multiple mixed system of molecule lean solution, computer capacity is very extensive, thereby has a wide range of applications in actual chemistry, Chemical Engineering Calculation process;

(3) technological design of computing method of the present invention in extensive, polycomponent mixed system, estimation and assessment, the process optimization of separation efficiency that product transforms, and fluid-phase macroscopic property accurately all has a wide range of applications the aspect such as improvement of control and equipment.

Accompanying drawing explanation

For content of the present invention is more easily expressly understood, according to specific embodiment also by reference to the accompanying drawings, the present invention is further detailed explanation, wherein below

Fig. 1 is that mixed system multiple chemical molecular balance calculates system flowchart;

Fig. 2 is calculated mixed system classification;

Fig. 3 is mixed system multi-chemical Equilibrium computing system;

Fig. 4 is that mixed system multiple chemical molecular balance calculates process false code.

Embodiment

[mixed system polycomponent multiple chemical molecular balance calculates algorithm]

The present invention is to arbitrary mixed system that has chemical reaction, and by selecting appropriate mode, the arbitrary reaction in this system always can be expressed as form below

React 1 θ ₁₁l ₁+ θ ₁₁l ₂+ ...+θ _1jl _j+ ... → S ₁

React 2 θ ₂₁l ₁+ θ ₂₁l ₂+ ...+θ _2jl _j+ ... → S ₂

......

Reaction i θ _i1l ₁+ θ _i1l ₂+ ...+θ _ijl _j+ ... → S _i

......

Reaction m θ _m1l ₁+ θ _m1l ₂+ ...+θ _mjl _j+ ... → S _m

Above-mentioned reaction can be noted the θ into Σ by abridging _ij.L _j=S _i.Wherein θ _ijbe L in i reaction _jstoichiometric coefficient, it can be negative.Compound or particulate S ₁, S ₂..., S _j... always can be regarded as by basic compound or particulate L ₁, L ₂..., L _j... reaction is transformed.{ S thus _ibe called species (Species), { L _jbe called component (Component).Obviously from form, L _jalso can regard as by 0L ₁+ 0L ₂+ ...+1L _j+ ...+0L _mbe transformed, therefore belong to species { S _iin one, have .For example, there is reaction system:

CH ₄+2O ₂→CO ₂+2H ₂O(g)；2CH ₄+3O ₂→2CO+4H ₂O(g)

Can be by CH ₄, O ₂, H ₂o (g) sees the component of architectonical, product C O, CO ₂claim altogether the species of system with the former.

For the fluid-phase mixed system of m component of arbitrary existence interaction, become n species owing to there is chemical reaction symbiosis.Take pure component as reference state, the Gibbs free energy g of whole system can be expressed as follows:

$g=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+g^{\mathrm{id},\mathrm{mix}}+g^{\mathrm{ex}}=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln x_i+\mathrm{\Σ}{X}_i\mathrm{RT}\ln f_i,$

(4)

In conjunction with Gibbs-Duhem equation, the chemical potential that above formula differential obtains each species is

${\mathrm{\μ}}_i=\∂g/\∂X_i={\mathrm{\ϵ}}_i^0+\mathrm{RT}\ln f_i+\mathrm{RT}\ln x_i={\mathrm{\ϵ}}_i^0+\mathrm{RT}\ln a_i$

(5)

Wherein, X _i, , μ _i, f _i, a _i, g ^{id, mix}, g ^ex, R, T is expressed as the amount of substance of species, reference state mole Gibbs free energy, chemical potential, activity coefficient, activity, the desirable mixing energy of mixed system, the Gibbs free energy that exceeds the quata, gas law constant, thermodynamic temperature.X _i=X _i/ N _tfor species mole fraction, N _tfor the total amount of substance of system particulate, and there is N _t=Σ X _k, material balance meets N _{θ j}=Σ X _iθ _ij, N _{θ j}it is initial total amount of substance of j component.

Condition when system reaches thermodynamic equilibrium, utilizes Lagrange factorization method, order

$\mathrm{\φ}(X_1,...,X_i,...)=g-{\mathrm{\α}}_1\left(\mathrm{\Σ}{X}_1{\mathrm{\θ}}_{i1}\right)-...{\mathrm{\α}}_j(\mathrm{\Σ}{X}_i{\mathrm{\θ}}_{\mathrm{ij}}-N_{\mathrm{\θj}})-...$

(6)

If the Langrade coefficient in j material balance relationship formula is α _j, ask g _minunder X _iconcentration is allocated as follows

$\frac{\∂\mathrm{\φ}}{{\∂X}_i}=\frac{\∂}{{\∂X}_i}[g-{\mathrm{\α}}_1(\mathrm{\Σ}{X}_1{\mathrm{\θ}}_{\mathrm{il}}-N_{\mathrm{\θ}1})-...{\mathrm{\α}}_j(\mathrm{\Σ}{X}_i{\mathrm{\θ}}_{\mathrm{ij}}-N_{\mathrm{\θj}})-...]=0$

(7)

In conjunction with Gibbs-Duhem equation, when solution (7) obtains system thermodynamic equilibrium, condition is

${\mathrm{\ϵ}}_i^0+\mathrm{RT}\ln f_i+\mathrm{RT}\ln X_i/N_t-\mathrm{\Σ}{\mathrm{\α}}_j{\mathrm{\θ}}_{\mathrm{ij}}=0$

(8)

Stoichiometric coefficient for the j component that generates j species is 1, and all the other component stoichiometric coefficients are 0, therefore α _j=μ _jso formula (8) further can be expressed as letter knot

${\mathrm{\μ}}_i-\underset{j}{\mathrm{\Σ}}{\mathrm{\θ}}_{\mathrm{ij}}.{\mathrm{\μ}}_j=0$

(9)

Above formula shows the chemical potential μ of arbitrary species _iequal the chemical potential μ of the component that generates it _jalgebraic sum with its stoichiometric coefficient product.If above formula is to X _iproduct sum up, in conjunction with N _{θ j}=Σ X _iθ _ij, have further have

$\underset{i}{\mathrm{\Σ}}{X}_i{\mathrm{\ϵ}}_i^0+\underset{i}{\mathrm{\Σ}}{X}_i\mathrm{RT}\ln {\mathrm{\α}}_i=\underset{i}{\mathrm{\Σ}}{N}_{\mathrm{\θj}}{\mathrm{\ϵ}}_j^0+\underset{i}{\mathrm{\Σ}}{N}_{\mathrm{\θj}}\mathrm{RT}\ln {\mathrm{\α}}_j$

(10)

The minimum Gibbs free energy of whole mixed system is

$g_{\min }=\underset{i}{\mathrm{\Σ}}{X}_i({\mathrm{\ϵ}}_i^0+\mathrm{RT}\ln f_i+\mathrm{RT}\ln x_i)=\underset{i}{\mathrm{\Σ}}{X}_i{\mathrm{\μ}}_i=\underset{i}{\mathrm{\Σ}}{N}_{\mathrm{\θj}}{\mathrm{\μ}}_j$

(11)

$\left\{\begin{array}{c}\min :g=\underset{i}{\mathrm{\Σ}}{X}_i{\mathrm{\ϵ}}_i^0+g^{\mathrm{id},\mathrm{mix}}+g^{\mathrm{ex}}\\ \mathrm{grad}\left(g\right):\▿g=\frac{\∂g}{{\∂X}_i}={\mathrm{\μ}}_i{\mathrm{\ϵ}}_i^0+\mathrm{RT}\ln f_i+\mathrm{RT}\ln x_i\\ S.T:\mathrm{\Σ}{X}_i{\mathrm{\θ}}_{\mathrm{ij}}=N_{\mathrm{\θj}},\underset{i}{\mathrm{\Σ}}{X}_i=N_t,X_i\≥0\end{array}\right.$

(12)

In order to calculate the minimum value of system Gibbs free energy by optimum procedure and to be worth point (X most ₁, X ₂..., X _i...), draft objective function, gradient function and constraint condition as shown in Equation (10).This optimizing process can be realized by the optimum procedure such as donlp2, SNOPT, introduces in penalty function situation, adopts Lagrange factorization method to ask the extreme value of objective function, and structure Lagrange function is as follows

$\begin{array}{c}L(x,\mathrm{\λ},\mathrm{\μ})=f\left(x\right)-\underset{i}{\mathrm{\Σ}}{\mathrm{\λ}}_i.g_i\left(x\right)+\underset{i}{\mathrm{\Σ}}{\mathrm{\λ}}_j.h_j\left(x\right)\\ +\underset{i}{\mathrm{\Σ}}{\mathrm{\δ}}_i.\left[\max \right\{0,-g_i\left\}\right]+\underset{i}{\mathrm{\Σ}}{\mathrm{\σ}}_j.\left|h_j\left(x\right)\right|\end{array}$

(13)

Optimization procedure adopts Calculation By Sequential Quadratic Programming Method (SQP) to search for its global minimum.When meeting K-T condition

$\▿f\left(x\right)-\mathrm{\Σ}{\mathrm{\λ}}_i\▿g_i\left(x\right)+\mathrm{\Σ}{\mathrm{\λ}}_j\▿h_j\left(x\right)=0$

(14)

L (x, λ, μ) reaches minimum value, now system Gibbs free energy value minimum.In above formula, f (x), g _i(x), h _j(x) be respectively objective function, inequality constrain, equality constraint (seeing formula (10)).Concentration and Activity Calculation while obtaining each species balance after being out of shape by (8) are as follows

x _i=X _i/N _tlna _i=lnf _j+lnx _i(15)

Be out of shape to such an extent that the basic species equilibrium constant that generates arbitrary species is by formula (10)

$\ln K_i=\ln {\mathrm{\α}}_i-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}\ln {\mathrm{\α}}_j=-({\mathrm{\ϵ}}_i^0-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}{\mathrm{\ϵ}}_j^0)/\mathrm{RT}$

(16)

Correspondingly, generate the standard Gibbs free energy change of arbitrary species can be respectively calculated as follows

$G_{i,m}^0=-\mathrm{RT}\ln K_i(\mathrm{RT}\ln {\mathrm{\α}}_i-\underset{j}{\mathrm{\Σ}}{\mathrm{\θ}}_{\mathrm{ij}}\mathrm{RT}\ln {\mathrm{\α}}_j)={\mathrm{\ϵ}}_i^0-\underset{i}{\mathrm{\Σ}}{\mathrm{\θ}}_{\mathrm{ij}}{\mathrm{\ϵ}}_j^0---\left(17\right)$

[multiple chemical molecular balance calculates system and calculation process]

As shown in figures 1 and 3, mixed system multi-chemical Equilibrium computing system and calculation process are as follows:

(1) data input: the title { L of the each component of input mixed system _jand content { N _{θ j}, according to reaction Σ θ _ij.L _j=S _igenerate the title { S of each species _i, stoichiometric coefficient { θ _ij, reference state Gibbs free energy , temperature conditions T, mixed system type, and attached can growth data and tables of data.

(2) computation process initialization: according to each component { L _jamount of substance { N _{θ j}determine each species { S _iamount of substance { X _i; Determine mixed system and select appropriate thermodynamical model according to the type of mixed system, mixed system comprises gaseous mixture, electrolyte mixed solution, little molecular mixing system, large molecule lean solution system.

(3) mixed system Gibbs minimization of free energy calculates: the objective function in the Gibbs minimization of free energy process of mixed system is set according to formula (12) $g=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+g^{\mathrm{id},\mathrm{mix}}+g^{\mathrm{ex}}=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln x_i+\mathrm{\Σ}{X}_i\mathrm{RT}\ln f_i,$ , the gradient function of objective function function , and constraint condition Σ X _iθ _ij=N _{θ j}, Σ X _i=N _t, X _i>=0; Utilize thermodynamical model to calculate the activity coefficient f of each species _iand then calculate the gradient function of above-mentioned objective function and objective function, call again the optimum procedure such as donlp2 or SNOPT, utilize the mixed system Gibbs free energy of optimum procedure minimization calculation under constraint condition based on quadratic programming (SQP) algorithm step by step, when mixed system Gibbs free energy minimization value reach enough little after, stop calculating, return to objective function extreme point, i.e. the minimum value g of mixed system Gibbs free energy _minand g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...).

(4) described mixed system series balance character is calculated: by the amount of substance (X of each species of returning in mixed system Gibbs minimization of free energy computing module ₁, X ₂..., X _i...) and calculate the concentration x of each species _i, calculate the activity a of each species based on thermodynamical model _i, activity coefficient f _iand the activity a of each component _jand activity coefficient f _j, calculate the equilibrium constant { K that generates each species _iwith react Gibbs free energy change ; In order to guarantee the reliability of result of calculation, utilize checking activity a _iwith activity coefficient f _irationality, utilize $\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln a_i=\mathrm{\Σ}{N}_{\mathrm{\θj}}{\mathrm{\ϵ}}_j^0+\mathrm{\Σ}{N}_{\mathrm{\θj}}\mathrm{RT}\ln a_j$ Checking activity a _jwith activity coefficient f _jrationality, utilize checking equilibrium constant lnK _i=lna _i-Σ θ _ijlna _jcalculate rationality, utilize $\mathrm{\Δ}{G}_{i,m}^0={\mathrm{\ϵ}}_i^0-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}{\mathrm{\ϵ}}_j^0$ Confirmatory reaction process Gibbs free energy change $\mathrm{\Δ}{G}_{i,m}^0=-(\mathrm{RT}\ln a_i-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}\mathrm{RT}\ln a_j)$ Rationality.

(5) output result of calculation preservation: to described mixed system series balance character result of calculation, mixed system series balance character is calculated and exported and preserve.Output data comprise the equilibrium concentration { x of each species _i, activity coefficient { f _i, activity { a _i, the activity coefficient { f of each component _jand activity { a _j, generate the chemical equilibrium constant { K of each species _i, chemical reaction Gibbs free energy change

See Fig. 4, multicomponent fluid phase mixed system multi-chemical Equilibrium calculation procedure is by 1 master routine and five sub-program components, and master routine is mainly divided into five steps, as shown in Figure 1, is respectively i) data input; Ii) computation process initialization; Iii) mixed system Gibbs minimization of free energy calculates; Iv) calculate mixed system series balance character; V) result of calculation output and preservation.Five subroutines are respectively mixed system type identification and thermodynamical model selection, and mixed system Gibbs minimization of free energy calculates, and mixed system series balance character is calculated.

Without structure and the shape of considering mixed system particulate, allow to have certain interaction between particulate, under thermodynamical model is auxiliary, the multi-chemical Equilibrium in dissimilar fluid-phase mixed system can be described, be calculated to these computing method and system preferably, can calculate four kinds of different fluid-phase mixed systems, see Fig. 2, comprising:

(1) gaseous mixture system, applied heat mechanical model can be Chemical Reaction Model, the model that can expand selection has carat-amber dragon equation, van der Waals equation or other thermodynamical model;

(2) comprise electrolyte solution system, applied heat mechanical model can be Chemical Reaction Model, and the mould that can expand selection has Debye – H ü ckel, Pitzer model and other possible thermodynamical model;

(3) comprise little molecular solution system, applied heat mechanical model can be Chemical Reaction Model, and the model that can expand selection has model and other possible thermodynamical models such as NRTL, Wilson, UNIFAC;

(4) comprise large molecule lean solution system, applied heat mechanical model can be Chemical Reaction Model, and the model that can expand selection has the models such as UNIFAC and other possible thermodynamical model.

Fluid-phase mixed system multi-chemical Equilibrium computing system of the present invention has opening and extensibility, can expansion content comprise: input data can expansion, increase other selectable thermodynamical model, use other Novel Algorithm, the calculating of extendible other mixed system equilibrium property etc., can expansion content not affect above-mentioned various features.

Claims (5)

1. a fluid-phase mixed system multi-chemical Equilibrium computing system, it is characterized in that: described whole computing system comprises data input, calculates initialization, and mixed system Gibbs minimization of free energy calculates, mixed system series balance character is calculated, five modules of result of calculation output and preservation; To the common fluid-phase mixed system of several classes, when without considering that the structure of species and shape bring while affecting, the amount { X of the parent material of known each species _iand reference state mole Gibbs free energy , change { X _itime, the calculating of the Gibbs free energy by corresponding thermodynamical model to system, each species activity coefficient and activity coefficient, calculate the Gibbs free energy minimization value of whole mixed system by quadratic programming optimization algorithm (SQP) progressively, now obtain the amount of substance { X of each reactant and product under multi-chemical Equilibrium state _i, further counting system series balance state behavior thus.

2. fluid-phase mixed system multi-chemical Equilibrium computing system according to claim 1, is characterized in that: described computing system composition and calculation process are:

1) described data input, is by the title { L of the each component of mixed system _jand content { N _{θ j}, according to reaction θ _ij.L _j=S _igenerate the title { S of each species _i, stoichiometric coefficient { θ _ij, reference state Gibbs free energy , temperature conditions T, mixed system type, and attached can growth data and tables of data.

2) described calculating initialization is the amount of substance { L according to each component _jdetermine each species { S _ithe amount { X of parent material _i; Determine mixed system and select appropriate thermodynamical model according to the type of mixed system, mixed system comprises gaseous mixture, electrolyte mixed solution, little molecular mixing system, large molecule lean solution system;

3) described mixed system Gibbs minimization of free energy calculates, and is the objective function first arranging in the Gibbs minimization of free energy process of mixed system $g=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+g^{\mathrm{id},\mathrm{mix}}+g^{\mathrm{ex}}=\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln x_i+\mathrm{\Σ}{X}_i\mathrm{RT}\ln f_i,$ The gradient function of objective function function , and constraint condition then thermodynamical model calculates the activity coefficient f of each species _iand further calculate the gradient function of above-mentioned objective function and objective function, and then call donlp2 or SNOPT optimum procedure, complete Gibbs free energy minimization value based on quadratic programming optimization algorithm progressively and calculate, return to objective function extreme point, i.e. the minimum value g of mixed system Gibbs free energy _minand g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...);

4) described mixed system series balance character is calculated, and is the extreme point returning by mixed system Gibbs minimization of free energy computing module, i.e. g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...) and calculate the concentration x of each species _i, calculate the activity a of each species based on thermodynamical model _i, activity coefficient f _iand the activity a of each component _jand activity coefficient f _j, calculate the equilibrium constant { K that generates each species _iwith react Gibbs free energy change ; In order to guarantee the reliability of result of calculation, utilize checking activity a _iwith activity coefficient f _irationality, utilize $\mathrm{\Σ}{X}_i{\mathrm{\ϵ}}_i^0+\mathrm{\Σ}{X}_i\mathrm{RT}\ln a_i=\mathrm{\Σ}{N}_{\mathrm{\θj}}{\mathrm{\ϵ}}_j^0+\mathrm{\Σ}{N}_{\mathrm{\θj}}\mathrm{RT}\ln a_j$ Checking activity a _jwith activity coefficient f _jrationality, utilize checking equilibrium constant lnK _i=lna _i-Σ θ _ijlna _jcalculate rationality, utilize $\mathrm{\Δ}{G}_{i,m}^0={\mathrm{\ϵ}}_i^0-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}{\mathrm{\ϵ}}_j^0$ Confirmatory reaction process Gibbs free energy change $\mathrm{\Δ}{G}_{i,m}^0=-(\mathrm{RT}\ln a_i-\mathrm{\Σ}{\mathrm{\θ}}_{\mathrm{ij}}\mathrm{RT}\ln a_j)$ Rationality;

5) described result of calculation output, is to described mixed system series balance character computing module result of calculation, and mixed system series balance character is calculated and exported and preserve.

3. fluid-phase mixed system multi-chemical Equilibrium computing system according to claim 2, is characterized in that:

Described computing system is without considering microgranular texture and shape in mixed system and the impact bringing thereof, and the type of described mixed system comprises:

(1) gaseous mixture system, applied heat mechanical model is Chemical Reaction Model, the thermodynamical model that can expand selection has carat-amber dragon equation, van der Waals equation;

(2) comprise electrolyte solution system, applied heat mechanical model is Chemical Reaction Model, and the thermodynamical model that can expand selection has Debye – H ü ckel, Pitzer;

(3) comprise little molecular solution system, applied heat mechanical model is Chemical Reaction Model, and the thermodynamical model that can expand selection has NRTL, Wilson, UNIFAC;

(4) comprise large molecule lean solution system, applied heat mechanical model is Chemical Reaction Model, and the thermodynamical model that can expand selection has UNIFAC.

4. according to the fluid-phase mixed system multi-chemical Equilibrium computing system described in claim 1,2 or 3, it is characterized in that: described computing system determines that the component of mixed system and the method for species are: all regard every kind of molecule in mixed system or ion particulate as species { S _i; From species, select independent, basic species as reactant, obtain by certain stoichiometric coefficient reaction if arbitrary species all can be regarded as by these reactants, these reactants are as the component { L of mixed system _j.

5. according to the fluid-phase mixed system multi-chemical Equilibrium computing system described in claim 2 or 3, it is characterized in that: the minimum value g that calls the Gibbs free energy of outside optimum procedure calculating mixed system in described mixed system Gibbs minimization of free energy computation process _min, and be in g _minamount of substance (the X of lower each species ₁, X ₂..., X _i...), described outside optimum procedure is donlp2 or SNOPT program, based on the minimum value of Novel Algorithm (SQP) calculating target function progressively.