CN107832573A - Predict the numerical computation method of flue gas recirculation sintering matter thermal coupling process - Google Patents

Abstract

The present invention discloses a kind of numerical computation method for predicting flue gas recirculation sintering matter thermal coupling process, comprises the following steps, (1) establishes the bi dimension unstable state of the bed of material thermal coupling process of sinter bed in sintering machine；(2) fuel factor according to each material in homogeneous reaction model and heterogeneous reaction model solution sintering process, then solve the quality source item and heat source item in mathematical modeling governing equation；(3) convective term and diffusion term in governing equation are calculated according to heat and mass parameter, bed of material geometrical structure parameter；(4) mixture temperature in sinter bed and gas temperature, outlet at bottom flue-gas temperature and composition is calculated；(5) result of calculation that obtains in step (4) is subjected to contrast verification with actual result, determines the value of empirical coefficient；(6) emulation is optimized, sunykatuib analysis is carried out to the thermal parameter in actual production and operating parameter, to optimize flue gas recirculation sintering process.

Description

Predict the numerical computation method of flue gas recirculation sintering matter-thermal coupling process

Technical field

The present invention relates to iron ore sintering technical field, more particularly to one kind to be used to predict that flue gas recirculation sinters matter-hot coupling The computational methods of conjunction process.

Background technology

Sintering is one of agglomeration technology that currently the most important ones produces artificial high-grad iron ore deposit.First continuous pallettype sintering machine in the world Gone into operation in 1910 in the U.S..In the last thirty years, domestic and international sintering technology takes around optimization Iron Ore Matching in Sintering, technique and equipment aspect Obtained remarkable progress so that sintering deposit technical indicator steps up.However, there is iron ore resource, energy for conventional sintering technique The outstanding problem of 5 aspects such as source consumption, environmental protection, sintering process control and waste heat recovery, has become steel industry section Can emission reduction and " the wooden barrel short slab " in green low-carbon field and " severely afflicated area ".On October 1st, 2012, China comes into effect《Steel work Industry pollutant emission new standard》, cause pollution control and conservation measures that many iron companies are existing, be difficult to meet to discharge With the requirement of energy consumption standard, novel environment friendly SINTERING TECHNOLOGY is researched and developed, meets Sustainable Development of Enterprises needs into common recognition.

Flue gas recirculation sintering technology is intended to recycle part heat smoke caused by sintering machine, substitutes normal temperature air, as Sintering gas, realize while discharged gas fume total amount and pollutant discharge amount is significantly reduced, system is lifted using obvious heat of smoke The system thermal efficiency, reduce solid fuel consumption, reduce lower floor's sintering deposit superfusion, so as to improve the overall yield rate of sintering, it has also become burning Tie the study hotspot of process waste recovery.However, sintering production is more mistakes such as a flowing mass transfer, heat transfer reaction, phase transformation crystallization Complex process that journey parameter couples strongly, Multiinputoutput, nonlinear, large dead time, setting control are difficult to obtain completely The effect of meaning.Preferably to disclose sintering mechanism, the influence that avoids process time lag from bringing, it is necessary to carry out deep theory and grind Study carefully.As a kind of multidisciplinary general research meanses, numerical computation method is undoubtedly most representational sintering process machine now Manage research meanses.It breaches the Research Thinking of this "black box" formula of artificial intelligence, by establishing sintering process mathematical modeling, by Model determines the constant of each control loop, avoids people and sets caused uncertainty, and then optimal behaviour by rule of thumb Make.

Retrieval finds that the external numerical computations to sintering matter-thermal coupling process start from Leeds, England university in 1963 earliest Simulations of the P.A.Young (sintering deposit produces, metallurgical industry publishing house, 1981) to gas-solid heat convection in the bed of material.Thereafter Since over half a century, the scholar of the state such as France, Austria, Brazil, Australia, Iran, Japan, India, South Korea reports one after another The new achievement in research in road.The domestic Study on Numerical Simulation for sintering matter-thermal coupling process lags behind foreign countries about 25 years, mainly Concentrate on the colleges and universities such as University of Science ＆ Technology, Beijing, Central South University and Zhejiang University.In numerous research, extensively by follow-up scholar approval Creative achievement includes：R.W.Young (Ironmaking＆Steelmaking, 1977) takes the lead in using unreacted retract mould Type describes fuel combustion and flux thermal decomposition process；H.Toda et al. (Transactions ISIJ, 1984) takes the lead in considering Melt influence of the cladding phenomenon of high-temperature liquid-phase to solid fuel ignition speed；T.Kawaguchi et al. (Ironmaking Proceedings, 1987) take the lead in having paid close attention to iron ore fusing and thus caused stomatal limiting value, bed permeability, mineral group Change into sinter quality；F.Patisson et al. (Ironmaking＆ Steelmaking, 1991) takes the lead in expecting moisture Drying model in layer is characterized as constant rate of drying and falling-rate periods of drying two benches；N.K.Nath et al. (Steel Research International, 1997) take the lead in calculating ferriferous oxide and CO and H₂Three stage of reduction processes；M.V.Ramos et al. (ISIJ International, 2000) calculates the agglomeration of bed of material endoparticle using discrete element method； J.Mitterlehner et al. (ISIJ International, 2004) calculates carbonate in iron ore using thermogravimetric test The reactive kinetics parameters of composition thermal decomposition, and this is included in model；W.Yang et al. (ISIJ International, 2004) it is theoretical that solid-state mixing multiphase is proposed in a creative way, and uses two-flux model, takes the lead in considering consolidating in sinter bed Body radiation heat transfer process；H.Yamaoka et al. (ISIJ International, 2005) refer to solid phase ratio, solid phase hole The parameters such as rate, melting rate and pontic index predict the metallurgical index of sintering；Red bright et al. (the Central South University's journal natural science of dragon Version, 2008) propose by sintering process Warm status be described as the bed of material respectively band migrate thought；Zhou Hao et al. (ISIJ International, 2012) efficient thermal conductivity is introduced to improve heat conduction and the radiation heat transfer between sinter mixture particle； M.Pahlevaninezhad et al. (Energy, 2014) considers than reacting to each other between more comprehensive gaseous component first； 2014, Zhang little Hui et al. (Central South University's journal natural science edition, 2014) considered SO first₂Generation-absorption-removed Journey；Zhao adds pendant et al. (Combustion and Flame, 2014) is first to consider goethite dehydration and serpentine dehydration. Meanwhile simulation study so far, for flue gas recirculation process be related to deficiency and model accuracy have it is to be assessed：Publication number CN105468799A, patent name《Forecast the emulation mode of high-temp waste gas cycle sintering process heat state parameter》It is proposed a kind of logical Cross the microcosmic mathematical modeling of individual particle micro unit and solve the quality source item of sintering bed macromodel and the computational methods of heat source item, But this method three water translocation, decomposition of limestone, fuel combustion reactions only with simple model solution, and will circulation Interaction between the gaseous component that the introducing of flue gas may trigger is taken into account；H.Kang et al. (Proceedings of The Institution of Mechanical Engineers, Part A, 2012) directly using W.Yang et al. (ISIJ International, 2004) model carries out the calculating of flue gas recirculation process；H.Ahn et al. (Ironmaking and Steelmaking, 2013) two-dimensional numerical model of a flue gas recirculation sintering is developed using business procedure simulator, but not Its specific emulated computation method is made an explanation；Zhang little Hui et al. (Central South University's journal natural science edition, 2014) model is same Sample does not consider the reaction that may occur between the gaseous component of circulating flue gas.

By analysis, above-mentioned computational methods mainly also there are problems that it is following some：(1) model of nearly half is only examined Consider the heat and mass phenomenon in the bed of material, and do not consider the transition of bed structure；(2) most models only account for gas-solid Between forced-convection heat transfer, and for radiation and Heat Conduction Problems, be not related to substantially；(3) the heat and mass ginseng in governing equation Number, the excessively selection of thermal physical property parameter, empirical and freeing；(4) reaction mechanism for physical and chemical process discloses inadequate, Parameter value is theoretically unsound；(5) description for the interaction between gaseous component is extremely short of.Therefore, these models It is used for off-line operation analysis, the value for not possessing commercial Application substantially, for flue gas recirculation sintering process.

The content of the invention

In view of the above-mentioned problems, the invention reside in provide a kind of number for predicting flue gas recirculation sintering process matter-thermal coupling process Value calculating method, to simulate gas and sintered mix cross-exchange, reaction and bed structure change procedure in sintering process.

To reach above-mentioned purpose, the present invention proposes a kind of numerical value for predicting flue gas recirculation sintering process matter-thermal coupling process Computational methods, comprise the following steps：

(1) mathematical modeling of the bed of material thermal coupling process of sinter bed in sintering machine is established, the mathematical modeling is two dimension Unsteady Model, for describing the flowing, heat transfer burning and chemical reaction of sinter bed and gas cross-exchange in sintering machine；

(2) heterogeneous reaction model, homogeneous reaction model are established, is asked according to homogeneous reaction model and heterogeneous reaction model The fuel factor of each material in sintering process is solved, and using solving result weighted sum as the Mass Sources in mathematical modeling governing equation Item and heat source item；

(3) according to heat and mass parameter, the convective term in bed of material geometrical structure parameter computational mathematics model cootrol equation and Diffusion term；

(4) mathematical modeling is solved according to quality source item, heat source item, convective term and the diffusion term obtained in above-mentioned steps Governing equation, obtain mixture temperature and gas temperature in sinter bed, outlet at bottom flue-gas temperature and composition；Simulate sintered Change under journey different technical parameters and control parameter；

(5) obtain result of calculation and the actual flue gas recirculation sintered cup in step (4) are tested the experimental result that obtains and entered Row contrast verification, determine the value of empirical coefficient；

(6) emulation is optimized, sunykatuib analysis is carried out to the thermal parameter in actual production and operating parameter, to optimize cigarette Gas cycle sintering technique.

Further, the mathematical modeling governing equation includes：

Gaseous mass conservation equation：

Batch mixing mass-conservation equation：

Gas energy conservation equation：

Batch mixing energy conservation equation：

Gas momentum conservation equation：

The equation of gas state：

Definite condition is as follows：Primary condition is the T as t=0_s=T_g=T_ini；Boundary condition be as y=0,

Wherein, subscript g and s is respectively gas and batch mixing；

Subscript i and j are respectively gaseous component and solid phase components numbering；

Subscript k numbers for reaction；

X and y is respectively the coordinate in sintering machine length and thickness of feed layer direction；

ε is sinter bed porosity ,-；

T is the time, s；

Speed of the u and v respectively in x-axis and y-axis direction, m/s；

M is molecule molal weight, kg/mol；

ρ is density, kg/m³；

Cp is specific heat capacity, J/ (kgK)；

λ is thermal conductivity factor, W/ (mK)；

λ_s,effFor the synthesis effective thermal conductivity of batch mixing, W/ (mK)；

T is temperature, K；

R_kFor the generating rate speed of certain component in reaction k, mol/ (m³·s)；

μ_gFor aerodynamic force viscosity, Pas；

h_convFor gas-solid convection transfer rate, W/ (m²·K)；

As be solid phase particles specific surface area, m²/m³；

ΔH_kTo react k fuel factor, J/kg；

P is bed of material pressure, Pa；

F is viscous stress tensor ,-；

S is the loss of momentum, Pa/m caused by materialbeds comminution；

d_pFor batch mixing or the equivalent particle size of solid phase particles, m；

For the form factor of batch mixing or solid phase particles ,-；

R_gFor universal gas constant, J/ (molK)；

T_iniFor cloth temperature, K；

T_g,inFor the inlet air temperatures at the top of the bed of material, K；

T_s,0For the temperature of batch mixing at the top of the bed of material, K；

ε_mFor batch mixing blackness ,-；

σ is Stefan-Bolzmann constants, W/ (m²·K⁴)。

Further, it is characterised in that the heterogeneous reaction model includes as follows：

(1) water translocation model, the water translocation speed in the water translocation model are：

Wherein, β_mFor convective transfer coefficient, m/s；

WithRespectively steam partial pressure and saturation pressure, Pa；

W and W_cThe respectively physics water content and critical content of the control unit batch mixing, wt.%；

(2) fuel combustion models, fuel burn rate is in the fuel combustion models：

Wherein, α is imperfect combustion rate ,-, 1≤α≤2；

N be unit volume in solid phase components granule number, 1/m³；

δ is plaster layer thickness, m；

Cg is molar concentration of certain gaseous component in certain control unit, mol/m³；

D_effFor molecule effective diffusion cofficient, m²/s；

k_cFor kinetics constant, m/s, calculated by Arrhenius formula；

(3) flux thermally decomposes, and flux rhermal decomposition rate is in the heat of solution model：

Wherein, d_oAnd d_rRespectively particle initial particle and unreacted core particle diameter, m；

K_eqFor the equilibrium constant of reaction ,-；

For the gaseous component equilibrium concentration at a temperature of certain, mol/m³；

(4) calcium hydroxide thermal dissociation model, the calcium hydroxide thermal dissociation model medium-slaking lime thermal dissociation speed are：

Wherein, m₀And m_rThe content of initial time and unreacted calcium hydroxide respectively in control unit, kg/m³；

(5) ferriferous oxide reduction and re_oxidization model, it is redox in the ferriferous oxide reduction and re_oxidization model Reaction rate is：

Wherein, subscript i characterizes O₂、H₂With the reacting gas such as CO；

(6) mineral melt and SOLIDIFICATION MODEL, the mineral melt is melted with freezing rate with SOLIDIFICATION MODEL Minerals is：

Wherein, M_fFor melting rate ,-；

T_m1And T_m2Respectively melt initiation temperature degree and melting completes temperature, K.

Further, it is characterised in that the homogeneous reaction model and each reaction rate corresponding to it are：

CO second-time burning models, reaction rate are：

CO₂Disproportionated reaction model, reaction rate are：

CH₄Combustion model, reaction rate are：

H₂Combustion model, reaction rate are：

Water gas reaction model, reaction rate are：

CO₂Reduction reaction model, reaction rate are：

Further, it is characterised in that heat and mass parameter includes gas-solid convection transfer rate, mixed in the step (3) Material comprehensive effective thermal conductivity, the effective coefficient of molecular diffusion of gaseous component and gaseous component convective transfer coefficient；

The calculation formula of the gas-solid convection transfer rate is：

The calculation formula of batch mixing synthesis effective thermal conductivity is：

The calculation formula of the effective coefficient of molecular diffusion of gaseous component is：

The calculation formula of the gaseous component convective transfer coefficient is：

Wherein, R_eFor Reynolds numbers ,-；

P_rFor Prandlt numbers ,-；

S_cFor Schmidt numbers ,-；

ε_sFor solid phase components particle porosity ,-；

τ is solid phase components particle tortuosity ,-；

D and D_kThe respectively coefficient of molecular diffusion of gaseous component and Knudsen diffusion coefficient, m²/s；

d_poreFor the pore diameter of solid phase components particle, m.

Further, it is characterised in that bed of material geometrical structure parameter includes solid phase components pellet pores in the step (3) Rate, solid phase components equivalent particle particle diameter, bed of material shrinkage factor, bed of material voidage, batch mixing form factor and batch mixing equivalent particle size；

The calculation formula of the solid phase components particle porosity is：ε_s=1-0.4 × (100d₀)^0.15[1-max (0, min (1, M_f))f_s]；

The calculation formula of the solid phase components equivalent particle particle diameter is：

The calculation formula of the bed of material shrinkage factor is：

The calculation formula of the bed of material voidage is：

The calculation formula of the batch mixing form factor is：

The calculation formula of the batch mixing equivalent particle size is：

Wherein, f_sAnd f_s,maxRespectively bed of material shrinkage factor and maximum contraction rate ,-；

F is the ratio between unreacted core quality and initial reaction granular mass ,-；

f_aThe ratio between ash content gross mass at the end of for ash content quality and reaction ,-；

ε₀For the Initial Air Void of the bed of material ,-；

WithForm factor respectively before batch mixing fusing and after solidification ,-；

d₁For the equivalent particle size of sintering deposit, m.

Further, the condition of founding mathematical models is in the step (1)：

(1) gas in sinter bed and batch mixing are continuous phase；

(2) batch mixing includes 6 kinds of solid phase components and its reaction product, i.e., iron ore, return mine, fuel, basic solvent (lime Stone, dolomite, serpentine etc.), calcium hydroxide and mechanical water；Gas includes 7 kinds of gaseous components, i.e. N₂、O₂、CO₂、CO、H₂O(g)、 H₂、CH₄；

(3) in sintering process, the thermograde inside single particle is ignored；

(4) in sintering process, the heat convection between gas-solid two-phase is occupied an leading position, but the intragranular heat conduction of batch mixing and Radiation be can not ignore；

(5) ignition phase, high temperature gas flow have convection current and radiation effects to batch mixing at the top of the bed of material；In the down draft sintering stage, neglect Heat exchange slightly between top batch mixing and environment；

(6) pallet wall is impermeable and adiabatic that bottom grid section is adiabatic.

To reach above-mentioned purpose, the present invention proposes a kind of numerical value for predicting flue gas recirculation sintering process matter-thermal coupling process Computational methods, including at least establishing homogeneous reaction model, and solve the reaction rate of homogeneous reaction；The homogeneous reaction model bag Include CO second-time burnings model, CO₂Disproportionated reaction model, CH₄Combustion model, H₂Combustion model, water gas reaction model and CO₂ Reduction reaction model,

CO second-time burning reaction rate calculation formula are：

CO₂The calculation formula of disproportionated reaction speed is：

CH₄The calculation formula of combustion rate is：

H₂The calculation formula of combustion rate is：

The calculation formula of water gas reaction speed is：

CO₂The calculation formula of reduction reaction rate is：

Further, methods described is further comprising the steps of：

(1) mathematical modeling of matter-thermal coupling process of sinter bed in sintering machine is established, the mathematical modeling is non-for two dimension Steady-state model, for describing the flowing, heat transfer burning and chemical reaction of sinter bed and gas cross-exchange in sintering machine, together Shi Jianli heterogeneous reaction models；

(2) fuel factor according to each material in homogeneous reaction model and heterogeneous reaction model solution sintering process, and will Solving result weighted sum is as the quality source item and heat source item in mathematical modeling governing equation；

(3) according to heat and mass parameter, the convective term in bed of material geometrical structure parameter computational mathematics model cootrol equation and Diffusion term；

(4) mathematical modeling is solved according to quality source item, heat source item, convective term and the diffusion term obtained in above-mentioned steps Governing equation, obtain mixture temperature and gas temperature in sinter bed, outlet at bottom flue-gas temperature and composition；Simulate sintered Mixture temperature change under journey different technical parameters and control parameter；

(5) obtain result of calculation and the actual flue gas recirculation sintered cup in step (4) are tested the experimental result that obtains and entered Row contrast verification, determine the value of empirical coefficient；

(6) emulation is optimized, sunykatuib analysis is carried out to the thermal parameter in actual production and operating parameter, to optimize cigarette Gas cycle sintering technique.

Gaseous mass conservation equation：

Batch mixing mass-conservation equation：

Gas energy conservation equation：

Batch mixing energy conservation equation：

Gas momentum conservation equation：

The equation of gas state：

Definite condition is as follows：Primary condition is the T as t=0_s=T_g=T_ini；Boundary condition be as y=0,

Wherein, subscript g and s is respectively gas and batch mixing；

Subscript i and j are respectively gaseous component and solid phase components numbering；

Subscript k numbers for reaction；

X and y is respectively the coordinate in sintering machine length and thickness of feed layer direction；ε is sinter bed porosity ,-；

T is the time, s；

Speed of the u and v respectively in x-axis and y-axis direction, m/s；

M is molecule molal weight, kg/mol；

ρ is density, kg/m³；

Cp is specific heat capacity, J/ (kgK)；

λ is thermal conductivity factor, W/ (mK)；

λ_s,effFor the synthesis effective thermal conductivity of batch mixing, W/ (mK)；

T is temperature, K；

R_kFor the generating rate speed of certain component in reaction k, mol/ (m³·s)；

μ_gFor aerodynamic force viscosity, Pas；

h_convFor gas-solid convection transfer rate, W/ (m²·K)；

As be solid phase particles specific surface area, m²/m³；

ΔH_kTo react k fuel factor, J/kg；

P is bed of material pressure, Pa；

F is viscous stress tensor ,-；

S is the loss of momentum, Pa/m caused by materialbeds comminution；

d_pFor batch mixing or the equivalent particle size of solid phase particles, m；

For the form factor of batch mixing or solid phase particles ,-；

R_gFor universal gas constant, J/ (molK)；

T_iniFor cloth temperature, K；

T_g,inFor the inlet air temperatures at the top of the bed of material, K；

T_s,0For the temperature of batch mixing at the top of the bed of material, K；

ε_mFor batch mixing blackness ,-；

σ is Stefan-Bolzmann constants, W/ (m²·K⁴)。

Further, the heterogeneous reaction model includes as follows：

(1) water translocation model, the water translocation speed in the water translocation model are：

Wherein, β_mFor convective transfer coefficient, m/s；

WithRespectively steam partial pressure and saturation pressure, Pa；

W and W_cThe respectively physics water content and critical content of the control unit batch mixing, wt.%；

(2) fuel combustion models, fuel burn rate is in the fuel combustion models：

Wherein, α is imperfect combustion rate ,-, 1≤α≤2；

N be unit volume in solid phase components granule number, 1/m³；

δ is plaster layer thickness, m；

Cg is molar concentration of certain gaseous component in certain control unit, mol/m³；

D_effFor molecule effective diffusion cofficient, m²/s；

k_cFor kinetics constant, m/s, calculated by Arrhenius formula；

(3) flux thermally decomposes, and flux rhermal decomposition rate is in the heat of solution model：

Wherein, d_oAnd d_rRespectively particle initial particle and unreacted core particle diameter, m；

K_eqFor the equilibrium constant of reaction ,-；

For the gaseous component equilibrium concentration at a temperature of certain, mol/m³；

(4) calcium hydroxide thermal dissociation model, the calcium hydroxide thermal dissociation model medium-slaking lime thermal dissociation speed are：

Wherein, m₀And m_rThe content of initial time and unreacted calcium hydroxide respectively in control unit, kg/m³；

(5) ferriferous oxide reduction and re_oxidization model, it is redox in the ferriferous oxide reduction and re_oxidization model Reaction rate is：

Wherein, subscript i characterizes O₂、H₂With the reacting gas such as CO；

(6) mineral melt and SOLIDIFICATION MODEL, the mineral melt is melted with freezing rate with SOLIDIFICATION MODEL Minerals is：

Wherein, M_fFor melting rate ,-；

T_m1And T_m2Respectively melt initiation temperature degree and melting completes temperature, K.

Further, the heat and mass parameter includes gas-solid convection transfer rate, batch mixing integrates effective thermal conductivity, The effective coefficient of molecular diffusion of gaseous component and gaseous component convective transfer coefficient；

The calculation formula of the gas-solid convection transfer rate is：

The calculation formula of batch mixing synthesis effective thermal conductivity is：

The calculation formula of the effective coefficient of molecular diffusion of gaseous component is：

The calculation formula of the gaseous component convective transfer coefficient is：

Wherein, R_eFor Reynolds numbers ,-；

P_rFor Prandlt numbers ,-；

S_cFor Schmidt numbers ,-；

ε_sFor solid phase components particle porosity ,-；

τ is solid phase components particle tortuosity ,-；

D and D_kThe respectively coefficient of molecular diffusion of gaseous component and Knudsen diffusion coefficient, m²/s；

d_poreFor the pore diameter of solid phase components particle, m.

Further, the bed of material geometrical structure parameter includes solid phase components particle porosity, solid phase components equivalent particle Particle diameter, bed of material shrinkage factor, bed of material voidage, batch mixing form factor and batch mixing equivalent particle size；

The calculation formula of the solid phase components particle porosity is：ε_s=1-0.4 × (100d₀)^0.15[1-max (0, min (1, M_f))f_s]；

The calculation formula of the solid phase components equivalent particle particle diameter is：

The calculation formula of the bed of material shrinkage factor is：

The calculation formula of the bed of material voidage is：

The calculation formula of the batch mixing form factor is：

The calculation formula of the batch mixing equivalent particle size is：

Wherein, f_sAnd f_s,maxRespectively bed of material shrinkage factor and maximum contraction rate ,-；

F is the ratio between unreacted core quality and initial reaction granular mass ,-；

f_aThe ratio between ash content gross mass at the end of for ash content quality and reaction ,-；

ε₀For the Initial Air Void of the bed of material ,-；

WithForm factor respectively before batch mixing fusing and after solidification ,-；

d₁For the equivalent particle size of sintering deposit, m.

Further, in founding mathematical models, its condition is：

(1) gas in sinter bed and batch mixing are continuous phase；

(2) batch mixing includes 6 kinds of solid phase components and its reaction product, i.e., iron ore, return mine, fuel, basic solvent (lime Stone, dolomite, serpentine etc.), calcium hydroxide and mechanical water；Gas includes 7 kinds of gaseous components, i.e. N₂、O₂、CO₂、CO、H₂O(g)、 H₂、CH₄；

(3) in sintering process, the thermograde inside single particle is ignored；

(4) in sintering process, the heat convection between gas-solid two-phase is occupied an leading position, but the intragranular heat conduction of batch mixing and Radiation be can not ignore；

(5) ignition phase, high temperature gas flow have convection current and radiation effects to batch mixing at the top of the bed of material；In the down draft sintering stage, neglect Heat exchange slightly between top batch mixing and environment；

(6) pallet wall is impermeable and adiabatic that bottom grid section is adiabatic.

The beneficial effect that the present invention reaches：

1) present invention is flowed by the gas being described in detail in sintering process, reacts complicated coupling more, heat and mass couples, Bed structure transition etc., governing equation combination heterogeneous reaction model, homogeneous reaction model, heat and mass parameter and the bed of material is several What structural parameters, establish the mathematical modeling of flue gas recirculation sintering matter-thermal coupling process, have chemical reaction more comprehensively, pass Hot mode is more complete, bed structure change is more specific, the parameter physical significance advantage such as definitely；

2) computational methods proposed by the present invention, perfect many deficiencies existing for existing computational methods, are more pasted in mechanism Nearly actual sintered process, thus simulation precision is higher, the value for possessing commercial Application；

3) present invention can not only realize the optimization Simulation to the main thermal parameter of conventional sintering technique and operating parameter, more can Meets the needs of to flue gas recirculation technique Accurate Prediction；

4) present invention can to different fabric thickness and temperature, the speed of service, exhausting pressure, enter wind flow, the original of batch mixing Material proportioning (humidity, fuel, lime stone, dolomite, quick lime, iron ore), circulating flue gas state parameter (flow, temperature and into Point) etc. influence sintering process main thermal parameter and operating parameter carry out numerical computations, to analyze under different production status Sintering characteristic, the process control of sintering production can be optimized, and then promote the upgrading volume increase of flue gas recirculation sintering process and energy-conservation dirty Dye.

Brief description of the drawings

Fig. 1 is the method flow diagram in the embodiment of the present invention；

Fig. 2 is the process schematic of flue gas recirculation sintering；

Fig. 3 is the physical arrangement schematic diagram for establishing two-dimension unsteady state sintering matter-thermal coupling process mathematical model；

Fig. 4 is the analog result of the inventive method and the contrast verification of experimental result；

Fig. 5-Fig. 6 is the material layer temperature and smoke components change song at a temperature of the different circulating flue gas of the inventive method simulation Line.

Embodiment

With reference to Figure of description, the present invention will be further described.As shown in figure 1, specific implementation process of the present invention It is as follows：

Embodiment 1, as shown in figure 1, the specific implementation process of the present invention is as follows：

Step 1, the physical description of conventional sintering matter-thermal coupling process is established：

Shown in the sintering process schematic diagram sintered such as Fig. 2 flue gas recirculations.It is different according to temperature and physicochemical change, can be with Sinter bed is divided into sintering deposit band, combustion zone, preheating zone, excessively dry zone, wet bands from top to bottom.Five bands are successive after igniting Occur, constantly move down, it is last all to become sintering deposit band.

Conventional sintering extracts normal temperature air as sintering gas after firing, and flue gas recirculation sintering has then recycled burning Part heat smoke caused by knot machine is as sintering gas.In this way, the change of the height, composition of the size of amount of circulating gas, temperature (especially O₂), great influence will be produced to sintering process.In sintering production, in the case of cloth is uniform, sintering The difference of matter-Heat transmission on machine width can be ignored, that is to say, that sintering process can be reduced to thickness of feed layer Two-dimentional transmitting procedure on direction and sintering machine traffic direction.

Step 2, physical process is carried out simplifying hypothesis：

The simplification assumed condition for establishing described two-dimension unsteady state sintering matter-thermal coupling process mathematical model is as follows：

(1) gas in sinter bed and batch mixing are continuous phase；

(2) batch mixing includes 6 kinds of solid phase components and its reaction product, i.e., iron ore, return mine, fuel, basic solvent (lime Stone, dolomite, serpentine etc.), calcium hydroxide and mechanical water；Gas includes 7 kinds of gaseous components, i.e. N₂、O₂、CO₂、CO、H₂O(g)、 H₂、CH₄；

(3) in sintering process, it is contemplated that the granularity of batch mixing is smaller and particle inside heat transfer is strong enough, can be neglected single Thermograde inside particle；

(4) in sintering process, the heat convection between gas-solid two-phase is occupied an leading position, but the intragranular heat conduction of batch mixing and Radiation be can not ignore；

(5) ignition phase, convection current and radiation comprehensive function of the high temperature gas flow to batch mixing at the top of the bed of material are considered；Down draft sintering rank Section, ignore heat exchange between top batch mixing and environment；

(6) pallet wall is impermeable and adiabatic that bottom grid section is adiabatic.

Step 3, the mathematical modeling of two-dimension unsteady state sintering matter-thermal coupling process is established；It is specific to combine the two-dimentional non-steady of Fig. 3 Shown in the physical model schematic diagram of state sintering matter-thermal coupling process mathematical model, in sintering process, sintering gas is with certain Speed v_gThe bed of material is passed perpendicularly through from top to bottom, and sintered material is with u_sSpeed move horizontally, during which, there is inlet temperature T_g,in's Gas is with having temperature T_s, original depth H₀Solid produce orthogonal countercurrent flow, and a series of physical chemical change occurs.

Wherein, the governing equation of described two-dimension unsteady state sintering matter-thermal coupling process mathematical model includes：

Gaseous mass conservation equation：

Batch mixing mass-conservation equation：

Gas energy conservation equation：

Batch mixing energy conservation equation：

Gas momentum conservation equation：

The equation of gas state：

Definite condition：Primary condition is the T as t=0_s=T_g=T_ini；Boundary condition be as y=0,

In above formula, subscript g and s are respectively gas and batch mixing；Subscript i and j are respectively gaseous component and solid phase components numbering； Subscript k numbers for reaction；X and y is respectively the coordinate in sintering machine length and thickness of feed layer direction；ε is sinter bed hole Rate ,-；T is the time, s；Speed of the u and v respectively in x-axis and y-axis direction, m/s；M is molecule molal weight, kg/mol；ρ For density, kg/m³；Cp is specific heat capacity, J/ (kgK)；λ is thermal conductivity factor, W/ (mK)；λ_s,effEffectively led for the synthesis of batch mixing Hot coefficient, W/ (mK)；T is temperature, K；R_kFor the generating rate speed of certain component in reaction k, mol/ (m³·s)；μ_gFor gas Body dynamic viscosity, Pas； h_convFor gas-solid convection transfer rate, W/ (m²·K)；As be solid phase particles specific surface area, m²/ m³；ΔH_kTo react k fuel factor, J/kg；P is bed of material pressure, Pa；F is viscous stress tensor ,-；Caused by S is materialbeds comminution The loss of momentum, Pa/m；d_pFor batch mixing or the equivalent particle size of solid phase particles, m；For the form factor of batch mixing or solid phase particles ,-；Rg For universal gas constant, J/ (molK)；T_iniFor cloth temperature, K； T_g,inFor the inlet air temperatures at the top of the bed of material, K；T_s,0For material The temperature of layer top batch mixing, K；ε_mFor batch mixing blackness ,-；σ is Stefan-Bolzmann constants, W/ (m²·K⁴)。

Step 4, heterogeneous reaction model, homogeneous reaction model are established, according to homogeneous reaction model and heterogeneous reaction mould Type solves the fuel factor of each material in sintering process, and using solving result weighted sum as the matter in mathematical modeling governing equation Measure source item and heat source item；

The heterogeneous reaction model includes as follows：

(1) water translocation.Described water translocation model can be described asThe model includes moisture Evaporation and the process of water vapor condensation two, it is believed that when the actual partial pressure of vapor on certain control unit batch mixing surface in the bed of material is less than the temperature Degree under Saturated water vapor pressure when, moisture evaporation；Conversely, water vapor condensation.Water translocation speed is：

In formula, β_mFor convective transfer coefficient, m/s；WithRespectively steam partial pressure and saturation pressure, Pa；W and Wc is respectively the physics water content and critical content of the control unit batch mixing, wt.%.Work as R₁>0, characterize moisture evaporation；Work as R₁<0, Characterize water vapour condensation；As min (1, W/W_c)=1, characterize evaporation phase at constant speed；As min (1, W/W_c)<When 1, characterize reduction of speed and steam The hair stage.

(2) fuel combustion.Described fuel combustion models can be described as α C+O₂→2(α-1)CO+(2-α)CO₂.The model Think in sintering process that imperfect combustion occurs for fuel, 1≤α≤2 and α is bigger, imperfect combustion degree is higher.Fuel particle fires Burning meets contracting kernel normal form, and combustion process is by mass transfer of the reacting gas in particle surface air film, the diffusion in grieshoch and reaction circle The chemical reaction co- controlling in face.Fuel burn rate is：

In formula, α is imperfect combustion rate ,-, 1≤α≤2；N be reactant unit bodies product, 1/m³；δ is grey thickness Degree, m；Cg be certain control unit in gaseous component molar concentration, mol/m³；D_effFor molecule effective diffusion cofficient, m²/s；Kc is Kinetics constant, m/s, calculated by Arrhenius formula.

(3) flux thermally decomposes.Described flux thermal-decomposition model can be described as CaCO₃→CaO+CO₂With CaMg (CO₃)₂ →CaO+MgO+2CO₂.The model includes the thermal decomposition of lime stone and dolomite, it is believed that and decomposable process meets contracting kernel normal form, and by CO at this temperature₂Equilibrium concentration influences.Flux rhermal decomposition rate is：

In formula, do and dr are respectively particle initial particle and unreacted core particle diameter, m；K_eqFor the equilibrium constant of reaction ,-； For the gaseous component equilibrium concentration at a temperature of certain, mol/m³。

(4) calcium hydroxide thermal dissociation.Described calcium hydroxide thermal dissociation model can be described as Ca (OH)₂→CaO+ H₂O(g).Should Model is thought because hydrated lime particle is small, reaction surface area is big, heat transfer is fast, while sinter bed interior air-flow speed is big, therefore disappears Lime thermal dissociation process is not extended influence, and by by temperature and reaction conversion ratio co- controlling.Calcium hydroxide thermal dissociation speed is：

In formula, m₀And m_rThe content of initial time and unreacted calcium hydroxide respectively in control unit, kg/m³。

(5) ferriferous oxide reduction and re_oxidization.Described ferriferous oxide reduction and re_oxidization model can be described asThe model thinks that high price ferriferous oxide is easily by H in preheating and drying band₂With CO etc. is reduced；And in sintering deposit band, low price ferriferous oxide is then easily by O₂Re-oxidation.The model include high price ferriferous oxide with Three stage of reduction between iron simple substance and process is reoxidized, the kinetic parameter and balance parameters in differential responses stage area Not.The model thinks that course of reaction meets contracting kernel normal form, and is influenceed by reacting gas equilibrium concentration at this temperature.Ferriferous oxide Reduction and re_oxidization speed is：

In formula, subscript i characterizes O₂、H₂With the reacting gas such as CO.

(6) mineral melt and solidification.Described mineral melt can be described as " batch mixing (s) → melting liquid phase with SOLIDIFICATION MODEL (s, l) → sintering deposit (s) ".The model thinks that the melting of mineral arises from melt initiation temperature degree, terminates at melting and completes temperature；And The solidification of mineral is the inverse process of melting.Melt initiation temperature degree is thought and Al in batch mixing₂O₃、 SiO₂It is related to flux content, and Melting is completed temperature and determined by the CaO content in mineral, and by CaO-Fe₂O₃Phasor, which is looked into, to be taken.Mineral melt is with freezing rate：

In formula, M_fFor melting rate ,-；

T_m1And T_m2Respectively melt initiation temperature degree and melting completes temperature, K.

The homogeneous reaction model includes reacting to each other between gaseous component, specifically can be described as CH₄+2O₂→CO₂+2H₂O(g)、H2+0.5O₂→H₂O(g)、Deng in circulating flue gas it is each The secondary response occurred between gaseous component in the bed of material.It is considered herein that the generation of above-mentioned reaction, and because of these gaseous components The disproportionated reaction between solid phase components that triggers of presence, sinter matter-thermal coupling for establishing accurate flue gas recirculation and emulate System is most important.The model that reacts to each other between described gaseous component, using thermodynamic model, consider temperature, gas phase group Divide the influence of concentration, the effect of intercoupling be present between partial reaction.Each gaseous component reaction model and reaction rate are：

(1) CO second-time burnings model (CO+0.5O₂→CO₂), reaction rate is：

(2)CO₂Disproportionated reaction model (CO₂→CO+0.5O₂), reaction rate：

(3)CH₄Combustion model (CH₄+2O₂→CO₂+2H₂O (g)), reaction rate：

(4)H₂Combustion model (H₂+0.5O₂→H₂O (g)), reaction rate：

(5) water gas reaction model (CO+H₂O(g)→CO₂+H₂), reaction rate：

(6)CO₂Reduction reaction model (CO₂+H₂→CO+H₂O (g)), reaction rate：

Step 5, according to the convective term in heat and mass parameter, bed of material geometrical structure parameter computational mathematics model cootrol equation And diffusion term；

Wherein, the heat and mass parameter includes：

(1) gas-solid convection transfer rate.Described gas-solid convection transfer rate is determined by tube furnace local heat transfer Fitting formula, and demonstrated by the Comprehensive Correlation of analog result and actual sintered cup experimental result of the simulation software of the present invention Applicability, it is as follows：

In formula, Re is Reynolds numbers ,-；Pr is Prandlt numbers ,-.

(2) gaseous component convective transfer coefficient.Described gaseous component convective transfer coefficient is determined according to experiment Fitting formula, and applicability is demonstrated by the Comprehensive Correlation of analog result and actual experiment result, it is as follows：

In formula, Sc is Schmidt numbers ,-.

(3) batch mixing synthesis effective thermal conductivity.Described batch mixing integrates effective thermal conductivity by the spoke inside porous media Penetrate heat exchange to be folded in heat conduction, and consider the influence of porous media internal void, it is as follows：

(4) the effective coefficient of molecular diffusion of gaseous component.The effective coefficient of molecular diffusion of described gaseous component thinks gas phase group The diffusion divided inside solid phase particles is as follows by molecule diffusion and Knudsen diffusion double control：

In formula, ε_sFor solid phase components particle porosity ,-；τ is solid phase components particle tortuosity ,-；D and D_kRespectively gas phase The coefficient of molecular diffusion and Knudsen diffusion coefficient of component, m²/s；d_poreFor the pore diameter of solid phase components particle, m.

The bed of material geometrical structure parameter, including：

(1) solid phase components particle porosity：ε_s=1-0.4 × (100d₀)^0.15[1-max (0, min (1, M_f))f_s]；

(2) solid phase components equivalent particle particle diameter：

(3) bed of material shrinkage factor：

(4) bed of material voidage：

(5) batch mixing form factor：

(6) batch mixing equivalent particle size：

In above formula, fs and f_s,maxRespectively bed of material shrinkage factor and maximum contraction rate ,-；F is anti-for unreacted core quality and initially The ratio between granular mass is answered ,-；f_aThe ratio between ash content gross mass at the end of for ash content quality and reaction ,-；ε₀For the initial void of the bed of material Rate ,-；WithForm factor respectively before batch mixing fusing and after solidification ,-； d₁For the equivalent particle size of sintering deposit, m.

Step 6, mathematical modulo is solved according to quality source item, heat source item, convective term and the diffusion term obtained in above-mentioned steps The governing equation of type, the mixture temperature in sinter bed and gas temperature, outlet at bottom flue-gas temperature and composition is calculated；Mould Intend the change under sintering process different technical parameters and control parameter；

Step 7, by the mixture temperature and gas in the sinter bed under the different working conditions being calculated in step 6 Temperature, outlet at bottom flue-gas temperature and composition are compared with the experimental result that the experiment of actual flue gas recirculation sintered cup obtains and tested Card, the final value for obtaining empirical coefficient.

According to the method for the present invention, it is 250 DEG C, O to obtain circulating flue gas temperature₂Content is 19% operating mode Imitating result Contrast verification is carried out with actual sintered cup experimental result, comparing result is as shown in Figure 4.Two curves in Fig. 4 are respectively to expect Layer thickness direction at bed of material bottom 525mm and 225mm mixture temperature with sintering time change.According to Fig. 4 contrast The result, it is believed that computational methods accurate and effective proposed by the present invention.

Step 8, emulation is optimized.Verified with reference to the model of step 7, to the different thermal parameters of actual sintered process and Operating parameter, such as fabric thickness and temperature, the speed of service, exhausting pressure, enter wind flow, the raw material proportioning of batch mixing (humidity, combustion Material, lime stone, dolomite, quick lime, iron ore), circulating flue gas state parameter (flow, temperature and composition) carry out simulation point Analysis, to optimize the production of flue gas recirculation sintering process.

According to the method for the present invention, circulating flue gas O is obtained₂When content 19%, circulating flue gas flow velocity 0.6Nm/s, cigarette is circulated Analog result when temperature degree is respectively 100 DEG C, 200 DEG C and 300 DEG C is as shown in Figure 5 and Figure 6.Curve in Fig. 5 represents respectively On thickness of feed layer direction at the bed of material bottom 550mm, 290mm and 30mm mixture temperature with chassis position change.Fig. 6 In curve represent respectively sintering flue gas in O₂、CO₂Change with CO contents with chassis position.

The present invention carries out physical description to the matter-thermal coupling process of flue gas recirculation sintering first, secondly it is carried out must On the basis of that wants simplifies hypothesis, flue gas recirculation sintering matter-thermal coupling process mathematical model of two-dimension unsteady state, Ran Houtong are established The numerical simulation algorithm specified is crossed to handle model and utilize simulation algorithm to calculate batch mixing and gas temperature, calculating in the bed of material Outlet at bottom gas temperature and composition etc.；The experimental result logarithm value meter obtained is then tested according to actual flue gas recirculation sintered cup Calculate result to be verified and adjusted, to analyze the sintering characteristic under different production status comprehensively, reach optimization sintering process Purpose.

For conventional computational methods in heat and mass phenomenon, bed structure transition, parameter value, reaction mechanism etc. Existing deficiency, the present invention join for heterogeneous reaction model, homogeneous reaction model, heat and mass parameter and bed of material geometry Several considers, and can accurately solve quality source item, heat source item, convective term and the diffusion term of governing equation.Not only change Reaction is more comprehensive, heat transfer type is more complete, bed structure changes more specific, parameter physical significance definitely, and And closer to sintering actual production, therefore simulating degree is high.

Embodiment 2

A kind of numerical computation method for predicting flue gas recirculation sintering process matter-thermal coupling process is provided in this implementation, at least Including establishing homogeneous reaction model, and the reaction rate of homogeneous reaction is solved, the homogeneous reaction model includes CO second-time burnings Model, CO₂Disproportionated reaction model, CH₄Combustion model, H₂Combustion model, water gas reaction model and CO₂Reduction reaction model,

Wherein, CO second-time burnings reaction rate calculation formula is：

CO₂The calculation formula of disproportionated reaction speed is：

CH₄The calculation formula of combustion rate is：

H₂The calculation formula of combustion rate is：

The calculation formula of water gas reaction speed is：

CO₂The calculation formula of reduction reaction rate is：

Embodiment 3

As the concrete scheme of embodiment 2, methods described also comprises the following steps：

(1) mathematical modeling of matter-thermal coupling process of sinter bed in sintering machine is established, the mathematical modeling is non-for two dimension Steady-state model, for describing the flowing, heat transfer burning and chemical reaction of sinter bed and gas cross-exchange in sintering machine, That is, two-dimentional transmitting procedure sintering process being reduced on thickness of feed layer direction and sintering machine traffic direction, while establish non-equal Phase reaction model；Wherein, the governing equation of described two-dimension unsteady state sintering matter-thermal coupling process mathematical model includes：

(1.1) gaseous mass conservation equation：

(1.2) batch mixing mass-conservation equation：

(1.3) gas energy conservation equation：

(1.4) batch mixing energy conservation equation：

(1.5) gas momentum conservation equation：

(1.6) equation of gas state：

(1.7) definite condition：Primary condition is the T as t=0_s=T_g=T_ini；Boundary condition be as y=0,

In above formula, subscript g and s are respectively gas and batch mixing；Subscript i and j are respectively gaseous component and solid phase components numbering； Subscript k numbers for reaction；X and y is respectively the coordinate in sintering machine length and thickness of feed layer direction；ε is sinter bed hole Rate ,-；T is the time, s；Speed of the u and v respectively in x-axis and y-axis direction, m/s；M is molecule molal weight, kg/mol；ρ For density, kg/m³；Cp is specific heat capacity, J/ (kgK)；λ is thermal conductivity factor, W/ (mK)；λ_s,effEffectively led for the synthesis of batch mixing Hot coefficient, W/ (mK)；T is temperature, K；R_kFor the generating rate speed of certain component in reaction k, mol/ (m³·s)；μ_gFor gas Body dynamic viscosity, Pas； h_convFor gas-solid convection transfer rate, W/ (m²·K)；As be solid phase particles specific surface area, m²/ m³；ΔH_kTo react k fuel factor, J/kg；P is bed of material pressure, Pa；F is viscous stress tensor ,-；Caused by S is materialbeds comminution The loss of momentum, Pa/m；d_pFor batch mixing or the equivalent particle size of solid phase particles, m；For the form factor of batch mixing or solid phase particles ,-；R_g For universal gas constant, J/ (molK)；T_iniFor cloth temperature, K； T_g,inFor the inlet air temperatures at the top of the bed of material, K；T_s,0For material The temperature of layer top batch mixing, K；ε_mFor batch mixing blackness ,-；σ is Stefan-Bolzmann constants, W/ (m²·K⁴)。

The described heterogeneous reaction model includes as follows：

(1.8) water translocation.Described water translocation model can be described asThe model includes water It is divided to evaporation and the process of water vapor condensation two, it is believed that be somebody's turn to do when the actual partial pressure of vapor on certain control unit batch mixing surface in the bed of material is less than At a temperature of Saturated water vapor pressure when, moisture evaporation；Conversely, water vapor condensation.Water translocation speed is：

In formula, β_mFor convective transfer coefficient, m/s；WithRespectively steam partial pressure and saturation pressure, Pa；W and Wc is respectively the physics water content and critical content of the control unit batch mixing, wt.%.Work as R₁>0, characterize moisture evaporation；Work as R₁<0, Characterize water vapour condensation；As min (1, W/W_c)=1, characterize evaporation phase at constant speed；As min (1, W/W_c)<When 1, characterize reduction of speed and steam The hair stage.

(1.9) fuel combustion.Described fuel combustion models can be described as α C+O₂→2(α-1)CO+(2-α)CO₂.The mould Type thinks in sintering process that imperfect combustion occurs for fuel, 1≤α≤2 and α is bigger, and imperfect combustion degree is higher.Fuel Grain burning meets contracting kernel normal form, and combustion process is by mass transfer of the reacting gas in particle surface air film, the diffusion in grieshoch and anti- Answer the chemical reaction co- controlling at interface.Fuel burn rate is：

In formula, α is imperfect combustion rate ,-, 1≤α≤2；N be reactant unit bodies product, 1/m³；δ is grey thickness Degree, m；Cg be certain control unit in gaseous component molar concentration, mol/m³；D_effFor molecule effective diffusion cofficient, m²/s；Kc is Kinetics constant, m/s, calculated by Arrhenius formula.

(1.10) flux thermally decomposes.Described flux thermal-decomposition model can be described as CaCO₃→CaO+CO₂And CaMg (CO₃)₂→CaO+MgO+2CO₂.The model includes lime stone and dolomite thermally decomposes, it is believed that and decomposable process meets contracting kernel normal form, And by CO at this temperature₂Equilibrium concentration influences.Flux rhermal decomposition rate is：

In formula, do and dr are respectively particle initial particle and unreacted core particle diameter, m；K_eqFor the equilibrium constant of reaction ,-； For the gaseous component equilibrium concentration at a temperature of certain, mol/m³。

(1.11) calcium hydroxide thermal dissociation.Described calcium hydroxide thermal dissociation model can be described as Ca (OH)₂→CaO+ H₂O(g)。 The model is thought because hydrated lime particle is small, reaction surface area is big, heat transfer is fast, while sinter bed interior air-flow speed is big, therefore Calcium hydroxide thermal dissociation process is not extended influence, and by by temperature and reaction conversion ratio co- controlling.Calcium hydroxide thermal dissociation speed For：

In formula, m₀And m_rThe content of initial time and unreacted calcium hydroxide respectively in control unit, kg/m³。

(1.12) ferriferous oxide reduction and re_oxidization.Described ferriferous oxide reduction and re_oxidization model can be described asThe model thinks that high price ferriferous oxide is easily by H in preheating and drying band₂And CO Deng reduction；And in sintering deposit band, low price ferriferous oxide is then easily by O₂Re-oxidation.The model includes high price ferriferous oxide and iron For three stage of reduction between simple substance with reoxidizing process, the kinetic parameter and balance parameters in differential responses stage are otherwise varied. The model thinks that course of reaction meets contracting kernel normal form, and is influenceed by reacting gas equilibrium concentration at this temperature.Ferriferous oxide is also It is former to be with reoxidation rate：

In formula, subscript i characterizes O₂、H₂With the reacting gas such as CO.

(1.13) mineral melt and solidification.Described mineral melt can be described as " batch mixing (s) → fused solution with SOLIDIFICATION MODEL Phase (s, l) → sintering deposit (s) ".The model thinks that the melting of mineral arises from melt initiation temperature degree, terminates at melting and completes temperature； And the solidification of mineral is the inverse process of melting.Melt initiation temperature degree is thought and Al in batch mixing₂O₃、SiO₂It is related to flux content, And melt completion temperature and determined by the CaO content in mineral, and by CaO-Fe₂O₃Phasor, which is looked into, to be taken.Mineral melt and freezing rate For：

In formula, M_fFor melting rate ,-；T_m1And T_m2Respectively melt initiation temperature degree and melting completes temperature, K.

(2) fuel factor according to each material in homogeneous reaction model and heterogeneous reaction model solution sintering process, and will Solving result weighted sum is as the quality source item and heat source item in mathematical modeling governing equation；

(3) according to heat and mass parameter, the convective term in bed of material geometrical structure parameter computational mathematics model cootrol equation and Diffusion term；Wherein, the heat and mass parameter includes：

(3.1) gas-solid convection transfer rate.Described gas-solid convection transfer rate is true by tube furnace local heat transfer Fixed fitting formula, and the Comprehensive Correlation of the analog result for the simulation software for passing through the present invention and actual sintered cup experimental result is verified Applicability, it is as follows：

In formula, Re is Reynolds numbers ,-；Pr is Prandlt numbers ,-.

(3.2) gaseous component convective transfer coefficient.Described gaseous component convective transfer coefficient is equally true according to experiment Fixed fitting formula, and applicability is demonstrated by the Comprehensive Correlation of analog result and actual experiment result, it is as follows：

In formula, Sc is Schmidt numbers ,-.

(3.3) batch mixing synthesis effective thermal conductivity.Described batch mixing integrates effective thermal conductivity by inside porous media Radiation heat transfer is folded in heat conduction, and considers the influence of porous media internal void, as follows：

(3.4) the effective coefficient of molecular diffusion of gaseous component.The effective coefficient of molecular diffusion of described gaseous component thinks gas phase Diffusion of the component inside solid phase particles is as follows by molecule diffusion and Knudsen diffusion double control：

In formula, ε_sFor solid phase components particle porosity ,-；τ is solid phase components particle tortuosity ,-；D and D_kRespectively gas phase The coefficient of molecular diffusion and Knudsen diffusion coefficient of component, m²/s；d_poreFor the pore diameter of solid phase components particle, m.

The bed of material geometrical structure parameter, including：

(3.5) solid phase components particle porosity：ε_s=1-0.4 × (100d₀)^0.15[1-max (0, min (1, M_f))f_s]；

(3..6) solid phase components equivalent particle particle diameter：

(3.7) bed of material shrinkage factor：

(3.8) bed of material voidage：

(3.9) batch mixing form factor：

(3.10) batch mixing equivalent particle size：

In above formula, fs and f_s,maxRespectively bed of material shrinkage factor and maximum contraction rate ,-；F is anti-for unreacted core quality and initially The ratio between granular mass is answered ,-；f_aThe ratio between ash content gross mass at the end of for ash content quality and reaction ,-；ε₀For the initial void of the bed of material Rate ,-；WithForm factor respectively before batch mixing fusing and after solidification ,-； d₁For the equivalent particle size of sintering deposit, m.

(4) mathematical modeling is solved according to quality source item, heat source item, convective term and the diffusion term obtained in above-mentioned steps Governing equation, obtain mixture temperature and gas temperature in sinter bed, outlet at bottom flue-gas temperature and composition；Simulate sintered Change under journey different technical parameters and control parameter；

(5) mixture temperature and gas temperature in the sinter bed under the different working conditions that will be calculated in step (4) Checking is compared in the experimental result that degree, outlet at bottom flue-gas temperature and composition obtain with the experiment of actual flue gas recirculation sintered cup, The final value for obtaining empirical coefficient.

(6) emulation is optimized, with reference to the model checking obtained in (5), to the main of actual flue gas recirculation sintering process Thermal parameter and operating parameter, i.e. circulating flue gas state parameter (flow, temperature and composition) carry out sunykatuib analysis, to optimize flue gas The production of cycle sintering technique.

Embodiment 4

As the concrete scheme of embodiment 3, matter-thermal coupling process mathematical model is sintered establishing described two-dimension unsteady state Preceding the step of also carrying out simplifying hypothesis to physical process including one：

Specific simplified assumed condition is as follows：

(1) gas in sinter bed and batch mixing are continuous phase；

(2) batch mixing includes 6 kinds of solid phase components and its reaction product, i.e., iron ore, return mine, fuel, basic solvent (lime Stone, dolomite, serpentine etc.), calcium hydroxide and mechanical water；Gas includes 7 kinds of gaseous components, i.e. N₂、O₂、CO₂、CO、H₂O(g)、 H₂、CH₄；

(3) in sintering process, it is contemplated that the granularity of batch mixing is smaller and particle inside heat transfer is strong enough, can be neglected single Thermograde inside particle；

(4) in sintering process, the heat convection between gas-solid two-phase is occupied an leading position, but the intragranular heat conduction of batch mixing and Radiation be can not ignore；

(5) ignition phase, convection current and radiation comprehensive function of the high temperature gas flow to batch mixing at the top of the bed of material are considered；Down draft sintering rank Section, ignore heat exchange between top batch mixing and environment；

(6) pallet wall is impermeable and adiabatic that bottom grid section is adiabatic.

The present invention is flowed by the gas being described in detail in sintering process, reacts complicated coupling more, heat and mass couples, material Rotating fields transition etc., by governing equation combination heterogeneous reaction model, homogeneous reaction model, heat and mass parameter and bed of material geometry Structural parameters, the mathematical modeling of flue gas recirculation sintering matter-thermal coupling process is established, there is the more comprehensive, heat transfer that chemically reacts Mode is more complete, bed structure change is more specific, the parameter physical significance advantage such as definitely；

More than, only presently preferred embodiments of the present invention, but protection scope of the present invention is not limited thereto is any to be familiar with sheet Those skilled in the art the invention discloses technical scope in, the change or replacement that can readily occur in should all be covered Within protection scope of the present invention.Therefore, protection scope of the present invention should be defined by the protection domain that claim is defined.

Claims (10)

1. a kind of numerical computation method for predicting flue gas recirculation sintering matter-thermal coupling process, it is characterised in that including following step Suddenly：

(1) mathematical modeling of matter-thermal coupling process of sinter bed in sintering machine is established, the mathematical modeling is two-dimension unsteady state Model, for describing the flowing, heat transfer burning and chemical reaction of sinter bed and gas cross-exchange in sintering machine；

(2) heterogeneous reaction model, homogeneous reaction model are established, is burnt according to homogeneous reaction model and heterogeneous reaction model solution The fuel factor of each material during knot, and using solving result weighted sum as the quality source item in mathematical modeling governing equation and Heat source item；

(3) according to heat and mass parameter, the convective term in bed of material geometrical structure parameter computational mathematics model cootrol equation and diffusion ；

(4) control of mathematical modeling is solved according to quality source item, heat source item, convective term and the diffusion term obtained in above-mentioned steps Equation, obtain mixture temperature and gas temperature in sinter bed, outlet at bottom flue-gas temperature and composition；

(5) obtain result of calculation and the actual flue gas recirculation sintered cup in step (4) are tested the experimental result that obtains and carried out pair Than verifying, the value of empirical coefficient is determined；

(6) emulation is optimized, sunykatuib analysis is carried out to the thermal parameter in actual production and operating parameter, followed with optimizing flue gas Ring sintering process.

2. the numerical computation method of prediction flue gas recirculation sintering matter-thermal coupling process according to claim 1, its feature exist In the mathematical modeling governing equation includes：

Gaseous mass conservation equation：

Batch mixing mass-conservation equation：

Gas energy conservation equation：

Batch mixing energy conservation equation：

Gas momentum conservation equation：

The equation of gas state：

Definite condition is as follows：Primary condition is the T as t=0_s=T_g=T_ini；Boundary condition be as y=0,

Wherein, subscript g and s is respectively gas and batch mixing；

Subscript i and j are respectively gaseous component and solid phase components numbering；

Subscript k numbers for reaction；

X and y is respectively the coordinate in sintering machine length and thickness of feed layer direction；

ε is sinter bed porosity ,-；

T is the time, s；

Speed of the u and v respectively in x-axis and y-axis direction, m/s；

M is molecule molal weight, kg/mol；

ρ is density, kg/m³；

Cp is specific heat capacity, J/ (kgK)；

λ is thermal conductivity factor, W/ (mK)；

λ_s,effFor the synthesis effective thermal conductivity of batch mixing, W/ (mK)；

T is temperature, K；

R_kFor the generating rate speed of certain component in reaction k, mol/ (m³·s)；

μ_gFor aerodynamic force viscosity, Pas；

h_convFor gas-solid convection transfer rate, W/ (m²·K)；

As be solid phase particles specific surface area, m²/m³；

ΔH_kTo react k fuel factor, J/kg；

P is bed of material pressure, Pa；

F is viscous stress tensor ,-；

S is the loss of momentum, Pa/m caused by materialbeds comminution；

d_pFor batch mixing or the equivalent particle size of solid phase particles, m；

For the form factor of batch mixing or solid phase particles ,-；

R_gFor universal gas constant, J/ (molK)；

T_iniFor cloth temperature, K；

T_g,inFor the inlet air temperatures at the top of the bed of material, K；

T_s,0For the temperature of batch mixing at the top of the bed of material, K；

ε_mFor batch mixing blackness ,-；

σ is Stefan-Bolzmann constants, W/ (m²·K⁴)。

3. the computational methods of prediction flue gas recirculation sintering matter-thermal coupling process value according to claim 1, its feature exist In the heterogeneous reaction model includes as follows：

(1) water translocation model, the water translocation speed in the water translocation model are：

Wherein, β_mFor convective transfer coefficient, m/s；

WithRespectively steam partial pressure and saturation pressure, Pa；

W and W_cThe respectively physics water content and critical content of the control unit batch mixing, wt.%；

(2) fuel combustion models, fuel burn rate is in the fuel combustion models：

Wherein, α is imperfect combustion rate ,-, 1≤α≤2；

N be unit volume in solid phase components granule number, 1/m³；

δ is plaster layer thickness, m；

Cg is molar concentration of certain gaseous component in certain control unit, mol/m³；

D_effFor molecule effective diffusion cofficient, m²/s；

k_cFor kinetics constant, m/s, calculated by Arrhenius formula；

(3) flux thermally decomposes, and flux rhermal decomposition rate is in the heat of solution model：

Wherein, d_oAnd d_rRespectively particle initial particle and unreacted core particle diameter, m；

K_eqFor the equilibrium constant of reaction ,-；

For the gaseous component equilibrium concentration at a temperature of certain, mol/m³；

(4) calcium hydroxide thermal dissociation model, the calcium hydroxide thermal dissociation model medium-slaking lime thermal dissociation speed are：

Wherein, m₀And m_rThe content of initial time and unreacted calcium hydroxide respectively in control unit, kg/m³；

(5) ferriferous oxide reduction and re_oxidization model, redox reaction in the ferriferous oxide reduction and re_oxidization model Speed is：

Wherein, subscript i characterizes O₂、H₂With the reacting gas such as CO；

(6) mineral melt and SOLIDIFICATION MODEL, the mineral melt is melted with freezing rate with SOLIDIFICATION MODEL Minerals is：

M_f=min (1, max (0, ((T_s-T_m1)/(T_m1-T_m2))³))

Wherein, M_fFor melting rate ,-；

T_m1And T_m2Respectively melt initiation temperature degree and melting completes temperature, K.

4. the computational methods of prediction flue gas recirculation sintering matter-thermal coupling process value according to claim 1, its feature exist In the homogeneous reaction model and each reaction rate corresponding to it are：

CO second-time burning models, reaction rate are：

CO₂Disproportionated reaction model, reaction rate are：

CH₄Combustion model, reaction rate are：

H₂Combustion model, reaction rate are：

Water gas reaction model, reaction rate are：

CO₂Reduction reaction model, reaction rate are：

5. the computational methods of prediction flue gas recirculation sintering matter-thermal coupling process value according to claim 1, its feature exist In heat and mass parameter includes gas-solid convection transfer rate, batch mixing synthesis effective thermal conductivity, gas phase group in the step (3) Divide effective coefficient of molecular diffusion and gaseous component convective transfer coefficient；

The calculation formula of the gas-solid convection transfer rate is：

The calculation formula of batch mixing synthesis effective thermal conductivity is：

The calculation formula of the effective coefficient of molecular diffusion of gaseous component is：

The calculation formula of the gaseous component convective transfer coefficient is：

Wherein, R_eFor Reynolds numbers ,-；

P_rFor Prandlt numbers ,-；

S_cFor Schmidt numbers ,-；

ε_sFor solid phase components particle porosity ,-；

τ is solid phase components particle tortuosity ,-；

D and D_kThe respectively coefficient of molecular diffusion of gaseous component and Knudsen diffusion coefficient, m²/s；

d_poreFor the pore diameter of solid phase components particle, m.

6. the computational methods of prediction flue gas recirculation sintering matter-thermal coupling process value according to claim 1, its feature exist In, in the step (3) bed of material geometrical structure parameter include solid phase components particle porosity, solid phase components equivalent particle particle diameter, Bed of material shrinkage factor, bed of material voidage, batch mixing form factor and batch mixing equivalent particle size；

The calculation formula of the solid phase components particle porosity is：ε_s=1-0.4 × (100d₀)^0.15[1-max (0, min (1, M_f))f_s]；

The calculation formula of the solid phase components equivalent particle particle diameter is：

The calculation formula of the bed of material shrinkage factor is：

The calculation formula of the bed of material voidage is：

The calculation formula of the batch mixing form factor is：

The calculation formula of the batch mixing equivalent particle size is：

Wherein, f_sAnd f_s,maxRespectively bed of material shrinkage factor and maximum contraction rate ,-；

F is the ratio between unreacted core quality and initial reaction granular mass ,-；

f_aThe ratio between ash content gross mass at the end of for ash content quality and reaction ,-；

ε₀For the Initial Air Void of the bed of material ,-；

WithForm factor respectively before batch mixing fusing and after solidification ,-；

d₁For the equivalent particle size of sintering deposit, m.

7. the numerical computation method of prediction flue gas recirculation sintering matter-thermal coupling process according to claim 1, its feature exist In the condition of founding mathematical models is in the step (1)：

(1) gas in sinter bed and batch mixing are continuous phase；

(2) batch mixing includes 6 kinds of solid phase components and its reaction product, i.e., iron ore, return mine, fuel, basic solvent it is (lime stone, white Marble, serpentine etc.), calcium hydroxide and mechanical water；Gas includes 7 kinds of gaseous components, i.e. N₂、O₂、CO₂、CO、H₂O(g)、H₂、CH₄；

(3) in sintering process, the thermograde inside single particle is ignored；

(4) in sintering process, the heat convection between gas-solid two-phase is occupied an leading position, but the intragranular heat conduction of batch mixing and radiation It can not ignore；

(5) ignition phase, high temperature gas flow have convection current and radiation effects to batch mixing at the top of the bed of material；In the down draft sintering stage, ignore top Heat exchange between portion's batch mixing and environment；

(6) pallet wall is impermeable and adiabatic that bottom grid section is adiabatic.

8. a kind of numerical computation method for predicting flue gas recirculation sintering matter-thermal coupling process, it is characterised in that including at least foundation Homogeneous reaction model, and solve the reaction rate of homogeneous reaction；The homogeneous reaction model includes CO second-time burnings model, CO₂ Disproportionated reaction model, CH₄Combustion model, H₂Combustion model, water gas reaction model and CO₂Reduction reaction model,

CO second-time burning reaction rate calculation formula are：

CO₂The calculation formula of disproportionated reaction speed is：

CH₄The calculation formula of combustion rate is：

H₂The calculation formula of combustion rate is：

The calculation formula of water gas reaction speed is：

CO₂The calculation formula of reduction reaction rate is：

9. the numerical computation method of prediction flue gas recirculation sintering matter-thermal coupling process according to claim 8, its feature exist In methods described also comprises the following steps：

(1) mathematical modeling of matter-thermal coupling process of sinter bed in sintering machine is established, the mathematical modeling is two-dimension unsteady state Model, for describing the flowing, heat transfer burning and chemical reaction of sinter bed and gas cross-exchange in sintering machine, build simultaneously Vertical heterogeneous reaction model；

(2) fuel factor according to each material in homogeneous reaction model and heterogeneous reaction model solution sintering process, and will solve As a result weighted sum is as the quality source item and heat source item in mathematical modeling governing equation；

(3) according to heat and mass parameter, the convective term in bed of material geometrical structure parameter computational mathematics model cootrol equation and diffusion ；

(4) control of mathematical modeling is solved according to quality source item, heat source item, convective term and the diffusion term obtained in above-mentioned steps Equation, obtain mixture temperature and gas temperature in sinter bed, outlet at bottom flue-gas temperature and composition；Simulate sintering process not With the change under technological parameter and control parameter；

(5) obtain result of calculation and the actual flue gas recirculation sintered cup in step (4) are tested the experimental result that obtains and carried out pair Than verifying, the value of empirical coefficient is determined；

(6) emulation is optimized, sunykatuib analysis is carried out to the thermal parameter in actual production and operating parameter, followed with optimizing flue gas Ring sintering process.

10. the numerical computation method of prediction flue gas recirculation sintering matter-thermal coupling process according to claim 8, its feature It is, the mathematical modeling governing equation includes：

Gaseous mass conservation equation：

Batch mixing mass-conservation equation：

Gas energy conservation equation：

Batch mixing energy conservation equation：

Gas momentum conservation equation：

The equation of gas state：

Definite condition is as follows：Primary condition is the T as t=0_s=T_g=T_ini；Boundary condition be as y=0,

Wherein, subscript g and s is respectively gas and batch mixing；

Subscript i and j are respectively gaseous component and solid phase components numbering；

Subscript k numbers for reaction；

X and y is respectively the coordinate in sintering machine length and thickness of feed layer direction；

ε is sinter bed porosity ,-；

T is the time, s；

Speed of the u and v respectively in x-axis and y-axis direction, m/s；

M is molecule molal weight, kg/mol；

ρ is density, kg/m³；

Cp is specific heat capacity, J/ (kgK)；

λ is thermal conductivity factor, W/ (mK)；

λ_s,effFor the synthesis effective thermal conductivity of batch mixing, W/ (mK)；

T is temperature, K；

R_kFor the generating rate speed of certain component in reaction k, mol/ (m³·s)；

μ_gFor aerodynamic force viscosity, Pas；

h_convFor gas-solid convection transfer rate, W/ (m²·K)；

As be solid phase particles specific surface area, m²/m³；

ΔH_kTo react k fuel factor, J/kg；

P is bed of material pressure, Pa；

F is viscous stress tensor ,-；

S is the loss of momentum, Pa/m caused by materialbeds comminution；

d_pFor batch mixing or the equivalent particle size of solid phase particles, m；

For the form factor of batch mixing or solid phase particles ,-；

R_gFor universal gas constant, J/ (molK)；

T_iniFor cloth temperature, K；

T_g,inFor the inlet air temperatures at the top of the bed of material, K；

T_s,0For the temperature of batch mixing at the top of the bed of material, K；

ε_mFor batch mixing blackness ,-；

σ is Stefan-Bolzmann constants, W/ (m²·K⁴)。