CN108681794A - A method of obtaining the optimal heating curve of mild steel - Google Patents
A method of obtaining the optimal heating curve of mild steel Download PDFInfo
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- CN108681794A CN108681794A CN201810487949.7A CN201810487949A CN108681794A CN 108681794 A CN108681794 A CN 108681794A CN 201810487949 A CN201810487949 A CN 201810487949A CN 108681794 A CN108681794 A CN 108681794A
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- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
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- G06Q10/04—Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem"
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
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Abstract
The present invention relates to a kind of methods obtaining the optimal heating curve of mild steel, include the following steps：Step 1：Blank type, the parameter of fuel type and furnace structure of heater for rolling steel are collected, minimum rhythm is set；Step 2：It establishes using start rolling temperature as the heater for rolling steel overall balance model of target, heating furnace is divided into multiple infinitesimal sections, calculates separately the thermal balance of each infinitesimal；Step 3：Nonlinear integrated thermal balance type is parsed using genetic algorithm, obtains the optimal heating curve of heater for rolling steel mild steel of certain structure；Step 4：Optimal heating curve is applied in production scene.The present invention is based on the hot physical property of steel billet, the Thermal Synthetic weighing apparatus model for establishing heater for rolling steel, obtains optimal heating curve of the mild steel in heater for rolling steel, is applied in enterprise's control system, reach and improve mild steel heating quality and energy-efficient purpose, keeps the operation of heating furnace more reasonable.
Description
Technical field
The present invention relates to mild steel production technical fields, and in particular to a kind of side obtaining the optimal heating curve of mild steel
Method.
Background technology
Existing enterprise's heater for rolling steel operating instruction is built upon on the basis of operating experience, lacks the excellent of high efficiency, low cost
Change method.The optimization of operating instruction is needed to carry out through a large number of experiments, this method one is to need to equip related special dress
Standby, second is that not considering the particularity of heating furnace, it is bigger to produce disconnection with enterprise.Mild steel accounts in smelter product structure
According to large percentage, the temperature-rise period in heater for rolling steel is not only related to the quality of finished steel, but also influences entire
The energy consumption level of steel rolling process, influences enterprise product cost.
Existing enterprise's heater for rolling steel operating instruction is built upon on the basis of operating experience, lacks the excellent of high efficiency, low cost
Change method.Steel grade heating curve is determined, traditionally using experimental tests.But there are larger defects for this method, when
Determine that optimal heating curve is needed by many experiments, cost is higher；Second is that ignore heating furnace structure and with the influences such as fuel
Factor, therefore had little significance to enterprise's operation instruction using the optimal heating curve that traditional optimization obtains.
Invention content
To overcome the deficiency, the purpose of the present invention is to provide a kind of methods obtaining the optimal heating curve of mild steel.
The technical solution adopted by the present invention to solve the technical problems is：A kind of side obtaining the optimal heating curve of mild steel
Method includes the following steps：
Step 1：Blank type, the parameter of fuel type and furnace structure of heater for rolling steel are collected, most trifle is set
It plays；
Specifically, the blank type be batch components and the blank at each temperature the density, thermal capacitance of the steel grade,
Thermal conductivity, the ingredient of fuel, low heating value, theoretical air, theoretical flue gas, cigarette are than data such as coal skies；
Step 2：It establishes using start rolling temperature as the heater for rolling steel overall balance model of target, heating furnace is divided into multiple
Infinitesimal section calculates separately the thermal balance of each infinitesimal；
Specifically, the heat Balance Calculation includes the following contents:Heat income item QEnter, heat expenditure item QGo out, optimization method.
Specifically, the heat income item QEnterCalculation formula is seen below：
Qd=(the wet %+5581 of the wet %+15371 × C2H6 of the wet %+8578 × CH4 of the wet %+2580 × H2 of 3020 × CO ×
The wet % of H2S) × 4186.8=3.47 (GJ/Nm3)
Q enters=Bi*Qd=60000*3.47=208646.8 (GJ/Nm3)
Specifically, the heat expenditure item QGo outCalculation formula see below：
Q goes out=QSteel billet+QExhaust gas+QFurnace wall+QDoor+QWater+QOther
Wherein:
(1)QSteel billet
QSteel billet=ρ ∫z∫∫Steel billet section[Ji(Ti)-Ji-1(Ti-1)]dxdydz
In formula：
QSteel billet：The caloric receptivity of the steel billet of this micro unit section is trapped in unit interval, (J/h)；
P：Hourly output (t/h)=140t/h；
ρ：Steel billet density, kg/m3；
dz：This infinitesimal segment length, m；
Ji(Ti)：The specific enthalpy of steel billet, kcal/kg in this infinitesimal section；Ji×4186.8J/kg；
Ti：The cross-section temperature field of steel billet in this infinitesimal section, DEG C；
Ti-1：The cross-section temperature field of steel billet in the adjacent infinitesimal section in this infinitesimal section downstream, DEG C；
(2) Q exhaust gas
Q exhaust gas=(1-K) BiVncy (ty-t0)
In formula：
K：Unburned carbon loss rate takes K=0.01~0.02 for gaseous fuel；
Vn：The exhaust gas volumn (mark m3/m3) that unit of fuel generates when burning；
Amount of theoretical flue gas calculation formula：Theoretical air requirement L0=(wet %+0.5 × the H of 0.5 × CO2Wet %+2 × CH4Wet %+
3.5×C2H6Wet %+1.5 × H2The wet %-O of S2Wet %)/21；
Ln=1.1L0；
Amount of theoretical flue gas calculates：Amount of theoretical flue gas Vn=Vco2+VH2O+VSO2+VN2+VO2
Wherein：①Vco2The wet %+CH of=CO4Wet %+2 × C2H6Wet %+CO2Wet %；
②VH2O=H2Wet %+H2The wet %+H of S2Wet %+3 × the C of the wet %+2 × CH4 of O2H6Wet %+0.00124gLn；
g:The saturated vapor content of room temperature 1m3 air, g=18.9g/m3；
③VSO2=H2The wet % of S
④VN2=N2Wet %+0.79Ln
⑤VO2=0.21 (Ln-L0)
ty、t0：Respectively from kiln gas temperature (175 DEG C) and environment temperature DEG C (environment temperature is generally ignored)
cy：From kiln gas avergae specific heat (J/m3. DEG C).
CCO2=1767.9, CH2O=1519.8, CSO2=1869.4, CN2=1301, CO2=1331.4.
(3)QFurnace wall
QFurnace wall=∑ FWallqWall×1000(J/h)。
Wherein FWall：Heat dissipation area including furnace wall, furnace roof, FWall=(2HStove is high+BStove is wide)×Li Furnace superintendent(m2), Li furnace superintendents:This is micro-
Length of first section along furnace superintendent direction.L furnace superintendents=...+Li-1 furnace superintendent+Li furnace superintendent+Li+1 furnace superintendents+...；
qWall:Furnace wall unit area heat loss；
tWall:Stove internal face temperature (DEG C)；
t0：Stove external environment temperature (DEG C)；
aW：Furnace wall outside film coefficient is pressed《Industrial furnace design manual》P147 table 5-5,
S:The thickness (m) of furnace wall layers of material；
λ：The thermal conductivity [KJ/ (m.h. DEG C)] of furnace wall layers of material；
(4)QWater cooling part
QBeam=(55tL-18600)·ABeam×4186.8(J/h)；
QColumn=16.8 × tL·AColumn×4186.8(J/h)；
ABeam：Water film-cooled heat (m2)；
nBeam:Water radical；
D beams：Water beam outer diameter (m)；
L beams：Water length (m)；
AColumn=nColumn×π×DColumn×HColumn(m2)
nColumn:Column radical；
DColumn：Column outer diameter (m)；
HColumn：Stem height (m)；
(5)QFire door
QFire door=QSpoke+QIt overflows+QLintel
Wherein：
Tg:Temperature at fire door, K；
A：Door opened area, m2, A=B × BH；
φ：Angle modification coefficient, takes φ=0.55；
In unit interval door opened time, minute open a few minutes per hour；Then into fire door and discharging door
Radiation heat loss be respectively：
Wherein tG is fed、tG dischargesRespectively temperature at charging and discharging door, DEG C；
tWall：Inboard wall of furnace body face temperature at lintel；
tWater：The temperature of water in lintel, takes 31 DEG C；
S:The thickness (m) of lintel layers of material；
λ:The thermal conductivity [KJ/ (m.h. DEG C)] of lintel layers of material；
FDoor：The wall surface area of lintel；
(6)QOther
QOtherIncluding furnace bottom radiation loss, other radiation losses etc., the 2%-3% for the volume of receipts of generally reducing phlegm and internal heat, the present embodiment
Using QOther=0.03QEnter；
(7) according to each section of heating load calculate each section needed for the accumulation of heat scale of construction
By calculating above, heat storage requirement can get:
Specifically, the optimization method specifically includes optimum furnace target and constraints, wherein optimum furnace target
It is based on the requirement that rolling mill practice is distributed steel billet temperature, is constraint item with certain productive targets in production process
Part, seeks the optimum furnace distribution curve for meeting constraints, and the productive target is：
(1) it comes out of the stove the moment, the surface temperature of steel billet reaches the minimum temperature of rolling mill practice requirement, moment steel of coming out of the stove in other words
The deviation of the desired billet surface temperature of surface temperature and rolling mill practice of base is less than given value；
(2) deviation of the surface temperature of moment steel billet of coming out of the stove and the central temperature of steel billet meets the requirements, i.e. the section of steel billet
The temperature difference is less than given value；
(3) under the premise of meeting steel billet tapping temperature, the energy expenditure of steel billet is reduced as possible；
(4) time inside furnace for shortening steel billet as possible, improves the productivity of heating furnace；
(5) oxidization burning loss of steel billet is reduced as possible；
To above-mentioned productive target, in can not possibly in most cases taking into account simultaneously for actual production.Therefore this patent according to
Actual conditions are weighted processing to items, side the considerations of to embody under different working conditions to furnace optimizing index
The difference of emphasis establishes following optimum furnace object function：
Constraints is as follows:
(1) steel billet is come out of the stove the limitation of moment surface temperature and the difference of target surface temperature | TIt comes out of the stove steel table-T*|≤Δ
TThe given surface temperature difference；
(2) limitation for the moment steel billet maximum section temperature difference of coming out of the stove | TIt comes out of the stove steel table-TIt comes out of the stove steel center|≤ΔTThe given section temperature difference；
(3) restricted T of steel billet maximum heating speed in preheating sectionAverage forecast(k)-TAverage forecast(k-1)≤ΔTMaximum heating speed；
(4) the minimax furnace temperature restricted T that certain is put in heating furnaceI minimum furnace temperature≤TStove i≤TI maximum furnace temperature；
(5) functional relation between steel billet temperature distribution and furnace temperature of heating furnace distribution is：
TSteel is average(k)=F (TSteel is average(k-1),TStove(k-1)
Wherein：TIt comes out of the stove steel table、TIt comes out of the stove steel centerRespectively represent steel billet come out of the stove the moment actual measurement surface temperature and center forecast temperature
(℃)；
TAverage forecast：Average forecast temperature (DEG C) of the steel billet in stove；
ΔTMaximum heating speed、ΔTThe given surface temperature difference：Permitted maximum heating speed and the maximum section temperature difference (DEG C) when heating steel billet；
T*：The target tapping temperature (DEG C) of billet surface；
ΔTThe given surface temperature difference：Steel billet is come out of the stove the moment permitted maximum section temperature difference (DEG C)；
S：The furnace superintendent (m) of heating furnace；
v：Movement velocity (m/s) of the steel billet in heating furnace；
ω1、ω2、ω3、ω4：Weighting coefficient, and ω1、ω2、ω4＞ ＞ ω3；
N：Calculate the sampling number that steel billet averagely forecasts temperature.
First item in optimization aim indicates to come out of the stove to steel billet the requirement of moment surface temperature difference, embodies the table that steel billet is come out of the stove
Face temperature reaches rolling mill practice requirement this index, and Section 2 illustrates the requirement for the moment section temperature difference of coming out of the stove to steel billet, two
It is combined the productive target requirement for showing Rolling production process to heating steel billet technique, the Section 3 of majorized function indicates steel
Average forecast temperature of the base in stove, Section 4 indicate residence time of the steel billet in stove, and Section 3 and Section 4 embody pair
Energy-saving requirement during bloom production.
Step 3：Nonlinear integrated thermal balance type is parsed using genetic algorithm, obtains the heater for rolling steel of certain structure
The optimal heating curve of mild steel；
Step 4：Optimal heating curve is applied in production scene.
The invention has the advantages that：Based on the hot physical property of mild steel, the Thermal Synthetic weighing apparatus of heater for rolling steel is established
Model obtains optimal heating curve of the mild steel in heater for rolling steel, is applied in enterprise's control system, reaches raising low-carbon
Steel heating quality and energy-efficient purpose can meet the heating quality requirement of heating furnace and energy saving consumption, by ton steel section
5% can calculate, steel per ton can save 4 yuans, for producing 1000000 tons of heating furnace per year, year economic benefit up to 4,000,000 yuan, make plus
The operation of hot stove is more reasonable.
Description of the drawings
Fig. 1 is density with temperature's variation diagram of the mild steel of the present invention.
Fig. 2 is that chart is arranged in the steel grade selection of the present invention and rhythm.
Fig. 3 is that chart is arranged in the initial parameter of the present invention.
Fig. 4 is each section of Optimal Temperature and Yield mapping of the present invention.
Fig. 5 is that the blast furnace gas parameter of the present invention inputs chart.
Fig. 6 is the exhaust gas heat waste calculation chart of the present invention.
Fig. 7 is the furnace wall heat waste calculation chart of the present invention.
Fig. 8 is the water cooling part parameter setting chart of the present invention.
Fig. 9 is the fire door heat waste parameter chart of the present invention.
Figure 10 is the optimal Optimal Distribution value chart for heating curve and furnace temperature along furnace superintendent after the heat Balance Calculation of the present invention.
Figure 11 is the optimal heat supply curve graph of the present invention.
Figure 12 is the flow chart of the present invention.
Specific implementation mode
In conjunction with the accompanying drawings, the present invention is further explained in detail.
According to a kind of method obtaining the optimal heating curve of mild steel shown in Fig. 1 to Figure 12, include the following steps：
Step 1：Blank type, the parameter of fuel type and furnace structure of heater for rolling steel are collected, most trifle is set
It plays；
Specifically, the blank type be batch components (table 1) and the blank at each temperature the density of the steel grade,
Thermal capacitance (table 2, table 3), thermal conductivity (table 4), the ingredient of fuel, low heating value, theoretical air, theoretical flue gas, cigarette are than moneys such as coal skies
Material；
Step 2：It establishes using start rolling temperature as the heater for rolling steel overall balance model of target, heating furnace is divided into multiple
Infinitesimal section calculates separately the thermal balance of each infinitesimal；
Specifically, the heat Balance Calculation includes the following contents:
D1 heat takes in item QEnter
Qd=(the wet %+5581 of the wet %+15371 × C2H6 of the wet %+8578 × CH4 of the wet %+2580 × H2 of 3020 × CO ×
The wet % of H2S) × 4186.8=3.47 (GJ/Nm3),
Q enters=Bi*Qd=60000*3.47=208646.8 (GJ/Nm3).
D2 heat pays item QGo out
Q goes out=QSteel billet+QExhaust gas+QFurnace wall+QDoor+QWater+QOther
Wherein:
(2)QSteel billet
QSteel billet=ρ ∫z∫∫Steel billet section[Ji(Ti)-Ji-1(Ti-1)]dxdydz
In formula：
QSteel billet：The caloric receptivity of the steel billet of this micro unit section is trapped in unit interval, (J/h)；
P：Hourly output (t/h)=140t/h；
ρ：Steel billet density, kg/m3；
dz：This infinitesimal segment length, m；
Ji(Ti)：The specific enthalpy of steel billet, kcal/kg in this infinitesimal section；Ji×4186.8J/kg；
Ti：The cross-section temperature field of steel billet in this infinitesimal section, DEG C；
Ti-1：The cross-section temperature field of steel billet in the adjacent infinitesimal section in this infinitesimal section downstream, DEG C；
(2) Q exhaust gas
Q exhaust gas=(1-K) BiVncy (ty-t0)
In formula：
K：Unburned carbon loss rate takes K=0.01~0.02 for gaseous fuel；
Vn：The exhaust gas volumn (mark m3/m3) that unit of fuel generates when burning；
Amount of theoretical flue gas calculation formula：Theoretical air requirement L0=(wet %+0.5 × the H of 0.5 × CO2Wet %+2 × CH4Wet %+
3.5×C2H6Wet %+1.5 × H2The wet %-O of S2Wet %)/21；
Ln=1.1L0；
Amount of theoretical flue gas calculates：Amount of theoretical flue gas Vn=Vco2+VH2O+VSO2+VN2+VO2
Wherein：①Vco2The wet %+CH of=CO4Wet %+2 × C2H6Wet %+CO2Wet %；
②VH2O=H2Wet %+H2The wet %+H of S2Wet %+3 × the C of the wet %+2 × CH4 of O2H6Wet %+0.00124gLn；
g:The saturated vapor content of room temperature 1m3 air, g=18.9g/m3；
③VSO2=H2The wet % of S
④VN2=N2Wet %+0.79Ln
⑤VO2=0.21 (Ln-L0)
ty、t0：Respectively from kiln gas temperature (175 DEG C) and environment temperature DEG C (environment temperature is generally ignored)
cy：From kiln gas avergae specific heat (J/m3. DEG C).
CCO2=1767.9, CH2O=1519.8, CSO2=1869.4, CN2=1301, CO2=1331.4.
(4)QFurnace wall
QFurnace wall=∑ FWallqWall×1000(J/h)。
Wherein FWall：Heat dissipation area including furnace wall, furnace roof, FWall=(2HStove is high+BStove is wide)×Li
Furnace superintendent(m2), Li furnace superintendents:Length of this infinitesimal section along furnace superintendent direction.L furnace superintendents=...+Li-1
Furnace superintendent+Li furnace superintendent+Li+1 furnace superintendents+...；
qWall:Furnace wall unit area heat loss；
tWall:Stove internal face temperature (DEG C)；
t0：Stove external environment temperature (DEG C)；
aW：Furnace wall outside film coefficient is pressed《Industrial furnace design manual》P147 table 5-5,
S:The thickness (m) of furnace wall layers of material；
λ：The thermal conductivity [KJ/ (m.h. DEG C)] of furnace wall layers of material； (4)QWater cooling part
QBeam=(55tL-18600)·ABeam×4186.8(J/h)；
QColumn=16.8 × tL·AColumn×4186.8(J/h)；
ABeam：Water film-cooled heat (m2)；
nBeam:Water radical；
D beams：Water beam outer diameter (m)；
L beams：Water length (m)；
AColumn=nColumn×π×DColumn×HColumn(m2)
nColumn:Column radical；
DColumn：Column outer diameter (m)；
HColumn：Stem height (m)；
(5)QFire door
QFire door=QSpoke+QIt overflows+QLintel
Wherein：
Tg:Temperature at fire door, K；
A：Door opened area, m2, A=B × BH；
φ：Angle modification coefficient, takes φ=0.55；
In unit interval door opened time, minute open a few minutes per hour；
It is respectively into the radiation heat loss of fire door and discharging door then：
Wherein tG is fed、tG dischargesRespectively temperature at charging and discharging door, DEG C；
tWall：Inboard wall of furnace body face temperature at lintel；
tWater：The temperature of water in lintel, takes 31 DEG C；
S:The thickness (m) of lintel layers of material；
λ:The thermal conductivity [KJ/ (m.h. DEG C)] of lintel layers of material；
FDoor：The wall surface area of lintel；
(6)QOther
QOtherIncluding furnace bottom radiation loss, other radiation losses etc., the 2%-3% for the volume of receipts of generally reducing phlegm and internal heat, the present embodiment
Using QOther=0.03QEnter；
(7) according to each section of heating load calculate each section needed for the accumulation of heat scale of construction
By calculating above, heat storage requirement can get:
D3 optimization methods
Optimum furnace target is based on the requirement that rolling mill practice is distributed steel billet temperature, with certain in production process
A little productive targets are constraints, seek the optimum furnace distribution curve for meeting constraints, the productive target is：
(1) it comes out of the stove the moment, the surface temperature of steel billet reaches the minimum temperature of rolling mill practice requirement, moment steel of coming out of the stove in other words
The deviation of the desired billet surface temperature of surface temperature and rolling mill practice of base is less than given value；
(2) deviation of the surface temperature of moment steel billet of coming out of the stove and the central temperature of steel billet meets the requirements, i.e. the section of steel billet
The temperature difference is less than given value；
(3) under the premise of meeting steel billet tapping temperature, the energy expenditure of steel billet is reduced as possible；
(4) time inside furnace for shortening steel billet as possible, improves the productivity of heating furnace；
(5) oxidization burning loss of steel billet is reduced as possible；
To above-mentioned productive target, in can not possibly in most cases taking into account simultaneously for actual production.Therefore this patent according to
Actual conditions are weighted processing to items, side the considerations of to embody under different working conditions to furnace optimizing index
The difference of emphasis establishes following optimum furnace object function：
Constraints is as follows:
(1) steel billet is come out of the stove the limitation of moment surface temperature and the difference of target surface temperature | TIt comes out of the stove steel table-T*|≤Δ
TThe given surface temperature difference；
(2) limitation for the moment steel billet maximum section temperature difference of coming out of the stove | TIt comes out of the stove steel table-TIt comes out of the stove steel center|≤ΔTThe given section temperature difference；
(3) restricted T of steel billet maximum heating speed in preheating sectionAverage forecast(k)-TAverage forecast(k-1)≤ΔTMaximum heating speed；
(4) the minimax furnace temperature restricted T that certain is put in heating furnaceI minimum furnace temperature≤TStove i≤TI maximum furnace temperature；
(5) functional relation between steel billet temperature distribution and furnace temperature of heating furnace distribution is：
TSteel is average(k)=F (TSteel is average(k-1),TStove(k-1)
Wherein：TIt comes out of the stove steel table、TIt comes out of the stove steel centerRespectively represent steel billet come out of the stove the moment actual measurement surface temperature and center forecast temperature
(℃)；
TAverage forecast：Average forecast temperature (DEG C) of the steel billet in stove；
ΔTMaximum heating speed、ΔTThe given surface temperature difference：Permitted maximum heating speed and the maximum section temperature difference (DEG C) when heating steel billet；
T*：The target tapping temperature (DEG C) of billet surface；
ΔTThe given surface temperature difference：Steel billet is come out of the stove the moment permitted maximum section temperature difference (DEG C)；
S：The furnace superintendent (m) of heating furnace；
v：Movement velocity (m/s) of the steel billet in heating furnace；
ω1、ω2、ω3、ω4：Weighting coefficient, and ω1、ω2、ω4＞ ＞ ω3；
N：Calculate the sampling number that steel billet averagely forecasts temperature.
First item in optimization aim indicates to come out of the stove to steel billet the requirement of moment surface temperature difference, embodies the table that steel billet is come out of the stove
Face temperature reaches rolling mill practice requirement this index, and Section 2 illustrates the requirement for the moment section temperature difference of coming out of the stove to steel billet, two
It is combined the productive target requirement for showing Rolling production process to heating steel billet technique, the Section 3 of majorized function indicates steel
Average forecast temperature of the base in stove, Section 4 indicate residence time of the steel billet in stove, and Section 3 and Section 4 embody pair
Energy-saving requirement increases rhythm if not meeting heating steel billet quality during bloom production, recalculates.
Step 3：Nonlinear integrated thermal balance type is parsed using genetic algorithm, obtains the heater for rolling steel of certain structure
The optimal heating curve of mild steel；
Step 4：Optimal heating curve is applied in production scene.
The optimal heating curve of mild steel is calculated according to the above computational methods：
(1) steel grade select, see Fig. 2, select optimize steel grade for：Mild steel 0.23%C, while setting comes out of the stove rhythm as 40s；
(2) initial parameter is arranged, and sees Fig. 3；
(3) steel billet heat absorption display, selects optimum results file, shows each section of Optimal Temperature and yield, sees Fig. 4；
(4) fuel type selects, and according to the calorific value of offer, selects blast furnace gas as fuel, sees Fig. 5；
(5) exhaust gas heat waste calculates, and according to operating mode is calculated, environment temperature is set as 20 DEG C, and exhaust gas temperature is set as 200 DEG C, sees figure
6；
(6) furnace wall heat waste selects the parameter of acquiescence, sees Fig. 7；
(7) water cooling part heat waste calculates, and can be configured to parameters such as walking beam, fixed beam, columns according to reality, see figure
8；
(8) fire door heat waste modifies to fire door parameter, sees Fig. 9 according to actual conditions；
(9) heat Balance Calculation, click calculate, obtain it is optimal for heating curve and furnace temperature along the Optimal Distribution value of furnace superintendent, see figure
10, Figure 11.
1 low-carbon steel constitution table of table
| Steel grade | C | Si | S | P | Cr | Ni | W | Mo | V | Cu | Al | Ats |
| Mild steel 0.23%C | 0.23 | 0.11 | 0.034 | 0.034 | 0 | 0.074 | 0 | 0 | 0 | 0.13 | 0.01 | 0.036 |
2 mild steel thermal capacitance table (~600 DEG C) (J/kg DEG C) of table
| Steel grade temperature | 100 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 550 | 600 |
| Mild steel 0.23%C | 485.7 | 506.6 | 519.2 | 531.7 | 556.8 | 573.6 | 598.7 | 623.8 | 661.5 | 703.4 | 749.4 |
3 mild steel thermal capacitance table (650~1300 DEG C) (J/kg DEG C) of table
4 mild steel thermal conductivity table (0~600) of table (W/ (m ﹒ DEG C)
| Steel grade | 0 | 50 | 100 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 |
| Mild steel 0.23%C | 51.9 | 51.4 | 51.0 | 49.8 | 48.5 | 46.4 | 44.3 | 43.5 | 42.7 | 41.0 | 39.3 |
5 calorific value of gas of table
6 steel grade table of table
The present invention is not limited to the embodiment, anyone should learn that the structure made under the inspiration of the present invention becomes
Change, the technical schemes that are same or similar to the present invention are each fallen within protection scope of the present invention.
Technology that the present invention is not described in detail, shape, construction part are known technology.
Claims (6)
1. a kind of method obtaining the optimal heating curve of mild steel, it is characterised in that：Include the following steps：
Step 1：Blank type, the parameter of fuel type and furnace structure of heater for rolling steel are collected, minimum rhythm is set；
Step 2：It establishes using start rolling temperature as the heater for rolling steel overall balance model of target, heating furnace is divided into multiple infinitesimals
Section, calculates separately the thermal balance of each infinitesimal；
Step 3：Nonlinear integrated thermal balance type is parsed using genetic algorithm, obtains the heater for rolling steel low-carbon of certain structure
The optimal heating curve of steel；
Step 4：Optimal heating curve is applied in production scene.
2. a kind of method obtaining the optimal heating curve of mild steel according to claim 1, it is characterised in that：The blank
Type is density, thermal capacitance, the thermal conductivity of batch components and the blank steel grade at each temperature, the ingredient of fuel, low fever
Value, theoretical air, theoretical flue gas, cigarette are than data such as coal skies.
3. a kind of method obtaining the optimal heating curve of mild steel according to claim 1, it is characterised in that：The heat is flat
It includes the following contents that weighing apparatus, which calculates,:Heat income item QEnter, heat expenditure item QGo out, optimization method.
4. a kind of method obtaining the optimal heating curve of mild steel according to claim 3, it is characterised in that：The heat is received
Enter a Q and enter calculation formula to see below：
Qd=(wet %+5581 × the H2S of the wet %+15371 × C2H6 of the wet %+8578 × CH4 of the wet %+2580 × H2 of 3020 × CO
Wet %) × 4186.8=3.47 (GJ/Nm3)
Q enters=Bi*Qd=60000*3.47=208646.8 (GJ/Nm3).
5. a kind of method obtaining the optimal heating curve of mild steel according to claim 3, it is characterised in that：The heat branch
Go out a QGo outCalculation formula see below：
Q goes out=QSteel billet+QExhaust gas+QFurnace wall+QDoor+QWater+QOther
Wherein:
(1)QSteel billet
QSteel billet=ρ ∫z∫∫Steel billet section[Ji(Ti)-Ji-1(Ti-1)]dxdydz
In formula：
QSteel billet：The caloric receptivity of the steel billet of this micro unit section is trapped in unit interval, (J/h)；
P：Hourly output (t/h)=140t/h；
ρ：Steel billet density, kg/m3；
dz：This infinitesimal segment length, m；
Ji(Ti)：The specific enthalpy of steel billet, kcal/kg in this infinitesimal section；Ji×4186.8J/kg；
Ti：The cross-section temperature field of steel billet in this infinitesimal section, DEG C；
Ti-1：The cross-section temperature field of steel billet in the adjacent infinitesimal section in this infinitesimal section downstream, DEG C；
(2) Q exhaust gas
Q exhaust gas=(1-K) BiVncy (ty-t0)
In formula：
K：Unburned carbon loss rate takes K=0.01~0.02 for gaseous fuel；
Vn：The exhaust gas volumn (mark m3/m3) that unit of fuel generates when burning；
Amount of theoretical flue gas calculation formula：Theoretical air requirement L0=(wet %+0.5 × the H of 0.5 × CO2Wet %+2 × CH4Wet %+3.5 ×
C2H6Wet %+1.5 × H2The wet %-O of S2Wet %)/21；
Ln=1.1L0；
Amount of theoretical flue gas calculates：Amount of theoretical flue gas Vn=Vco2+VH2O+VSO2+VN2+VO2
Wherein：①Vco2The wet %+CH of=CO4Wet %+2 × C2H6Wet %+CO2Wet %；
②VH2O=H2Wet %+H2The wet %+H of S2Wet %+3 × the C of the wet %+2 × CH4 of O2H6Wet %+0.00124gLn；
g:The saturated vapor content of room temperature 1m3 air, g=18.9g/m3；
③VSO2=H2The wet % of S
④VN2=N2Wet %+0.79Ln
⑤VO2=0.21 (Ln-L0)
ty、t0：Respectively from kiln gas temperature (175 DEG C) and environment temperature DEG C (environment temperature is generally ignored)
cy：From kiln gas avergae specific heat (J/m3. DEG C).
CCO2=1767.9, CH2O=1519.8, CSO2=1869.4, CN2=1301, CO2=1331.4.
(3)QFurnace wall
QFurnace wall=∑ FWallqWall×1000(J/h)。
Wherein FWall：Heat dissipation area including furnace wall, furnace roof, FWall=(2HStove is high+BStove is wide)×LiFurnace superintendent(m2), Li furnace superintendents:This infinitesimal section edge
The length in furnace superintendent direction.L furnace superintendents=...+Li-1 furnace superintendent+Li furnace superintendent+Li+1 furnace superintendents+...；
qWall:Furnace wall unit area heat loss；
tWall:Stove internal face temperature (DEG C)；
t0：Stove external environment temperature (DEG C)；
aW：Furnace wall outside film coefficient is pressed《Industrial furnace design manual》P147 table 5-5,
S:The thickness (m) of furnace wall layers of material；
λ：The thermal conductivity [KJ/ (m.h. DEG C)] of furnace wall layers of material；
(4)QWater cooling part
QBeam=(55tL-18600)·ABeam×4186.8(J/h)；
QColumn=16.8 × tL·AColumn×4186.8(J/h)；
ABeam：Water film-cooled heat (m2)；
nBeam:Water radical；
D beams：Water beam outer diameter (m)；
L beams：Water length (m)；
AColumn=nColumn×π×DColumn×HColumn(m2)
nColumn:Column radical；
DColumn：Column outer diameter (m)；
HColumn：Stem height (m)；
(5)QFire door
QFire door=QSpoke+QIt overflows+QLintel
Wherein：
Tg:Temperature at fire door, K；
A：Door opened area, m2, A=B × BH；
φ：Angle modification coefficient, takes φ=0.55；
In unit interval door opened time, minute open a few minutes per hour；
It is respectively into the radiation heat loss of fire door and discharging door then：
Wherein tG is fed、tG dischargesRespectively temperature at charging and discharging door, DEG C；
tWall：Inboard wall of furnace body face temperature at lintel；
tWater：The temperature of water in lintel, takes 31 DEG C；
S:The thickness (m) of lintel layers of material；
λ:The thermal conductivity [KJ/ (m.h. DEG C)] of lintel layers of material；
FDoor：The wall surface area of lintel；
(6)QOther
QOtherIncluding furnace bottom radiation loss, other radiation losses etc., the 2%-3% for the volume of receipts of generally reducing phlegm and internal heat, the present embodiment use
QOther=0.03QEnter；
(7) according to each section of heating load calculate each section needed for the accumulation of heat scale of construction
By calculating above, heat storage requirement can get
6. a kind of method obtaining the optimal heating curve of mild steel according to claim 3, it is characterised in that：The optimization
Equation specifically includes optimum furnace target and constraints, and wherein optimum furnace target is with rolling mill practice to steel billet temperature
Based on the requirement of distribution, using certain productive targets in production process as constraints, seek the stove for meeting constraints
Warm Optimum distribution curve, the productive target are：
(1) it comes out of the stove the moment, the surface temperature of steel billet reaches the minimum temperature of rolling mill practice requirement, moment steel billet of coming out of the stove in other words
The deviation of surface temperature and the desired billet surface temperature of rolling mill practice is less than given value；
(2) deviation of the surface temperature of moment steel billet of coming out of the stove and the central temperature of steel billet meets the requirements, i.e. the section temperature difference of steel billet
Less than given value；
(3) under the premise of meeting steel billet tapping temperature, the energy expenditure of steel billet is reduced as possible；
(4) time inside furnace for shortening steel billet as possible, improves the productivity of heating furnace；
(5) oxidization burning loss of steel billet is reduced as possible；
To above-mentioned productive target, in can not possibly in most cases taking into account simultaneously for actual production.Therefore this patent is according to actual conditions pair
Items are weighted processing, and the difference of emphasis the considerations of to embody under different working conditions to furnace optimizing index is established
Following optimum furnace object function：
Constraints is as follows:
(1) steel billet is come out of the stove the restricted T of moment surface temperature and the difference of target surface temperatureIt comes out of the stove steel table-T*|≤ΔTThe given surface temperature difference；
(2) limitation for the moment steel billet maximum section temperature difference of coming out of the stove | TIt comes out of the stove steel table-TIt comes out of the stove steel center|≤ΔTThe given section temperature difference；
(3) restricted T of steel billet maximum heating speed in preheating sectionAverage forecast(k)-TAverage forecast(k-1)≤ΔTMaximum heating speed；
(4) the minimax furnace temperature restricted T that certain is put in heating furnaceI minimum furnace temperature≤TStove i≤TI maximum furnace temperature；
(5) functional relation between steel billet temperature distribution and furnace temperature of heating furnace distribution is：
TSteel is average(k)=F (TSteel is average(k-1),TStove(k-1)
Wherein：TIt comes out of the stove steel table、TIt comes out of the stove steel centerRespectively represent steel billet come out of the stove the moment actual measurement surface temperature and center forecast temperature (DEG C)；
TAverage forecast：Average forecast temperature (DEG C) of the steel billet in stove；
ΔTMaximum heating speed、ΔTThe given surface temperature difference：Permitted maximum heating speed and the maximum section temperature difference (DEG C) when heating steel billet；
T*：The target tapping temperature (DEG C) of billet surface；
ΔTThe given surface temperature difference：Steel billet is come out of the stove the moment permitted maximum section temperature difference (DEG C)；
S：The furnace superintendent (m) of heating furnace；
v：Movement velocity (m/s) of the steel billet in heating furnace；
ω1、ω2、ω3、ω4：Weighting coefficient, and ω1、ω2、ω4＞ ＞ ω3；
N：Calculate the sampling number that steel billet averagely forecasts temperature.
First item in optimization aim indicates to come out of the stove to steel billet the requirement of moment surface temperature difference, embodies the surface temperature that steel billet is come out of the stove
Degree reaches rolling mill practice requirement this index, and Section 2 illustrates the requirement for the moment section temperature difference of coming out of the stove to steel billet, and two are closed and exist
Productive target requirement of the Rolling production process to heating steel billet technique is together illustrated, the Section 3 of majorized function indicates that steel billet exists
Average forecast temperature in stove, Section 4 indicate residence time of the steel billet in stove, and Section 3 and Section 4 are embodied to steel billet
Energy-saving requirement in production process.
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| CN110362129A (en) * | 2019-07-19 | 2019-10-22 | 于政军 | A kind of heating cycle generation method based on steel billet key temperatures |
| CN115011786A (en) * | 2022-04-19 | 2022-09-06 | 北京科技大学 | Furnace temperature optimization method and device for dynamically sensing working condition of heating furnace |
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