CN110699502A - Method for high-precision prediction of gas consumption of blast furnace hot blast stove - Google Patents
Method for high-precision prediction of gas consumption of blast furnace hot blast stove Download PDFInfo
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Abstract
A method for predicting the gas consumption of a blast furnace hot blast stove with high precision aims at predicting the gas consumption of the blast furnace hot blast stove in the iron-making production process in advance and providing technical support for realizing dynamic gas optimization scheduling of iron and steel enterprises. The method is based on a blast furnace and hot blast furnace production plan and equipment maintenance plan, and establishes a single hot blast furnace gas consumption prediction model under various working conditions of the blast furnace according to hot blast furnace burning and air supply system and by referring to hot blast furnace heat balance test analysis report data, wherein the blast furnace working conditions comprise: normal production, wind reduction, damping down and reblowing working conditions; the method can predict the gas consumption of the blast furnace hot blast furnace with high precision (more than or equal to 95 percent), and lays a technical foundation for realizing dynamic optimization scheduling of the gas of the enterprise; has important effect on realizing zero diffusion of coal gas of enterprises.
Description
Technical Field
The invention relates to the technical field of metallurgical thermal energy conservation, in particular to a method for predicting the gas consumption of blast furnace hot blast stove with high precision.
Background
Coal gas is an important secondary energy source for iron and steel enterprises, the utilization efficiency of the coal gas is improved by optimizing the dynamic balance of a coal gas system, and zero diffusion of the coal gas is realized, so that the coal gas is the highest target of the optimized scheduling of the coal gas of each iron and steel enterprise. The basis for realizing the target is to accurately predict the gas generation amount and the gas consumption amount of enterprises. The blast furnace hot blast stove is a main user of blast furnace gas consumption and accounts for more than 40% of the total blast furnace gas consumption, so that accurate prediction of the blast furnace hot blast stove gas consumption is well made, and technical support can be provided for enterprises to realize dynamic balance and optimized scheduling of gas systems.
At present, two methods are generally adopted for predicting the gas consumption of the blast furnace hot blast stove, namely a time series prediction method which is based on a continuity principle, only if an assumed condition of 'the past is the same, and the future is the same' is met, historical data can be used for predicting the future of the blast furnace hot blast stove, and if the assumed condition is not met, the prediction accuracy is greatly reduced. The other is a causal relationship prediction method, which is based on the causal relationship prediction principle, and only if the antecedent condition of the cause decision result is established, the future of the causal relationship prediction method can be predicted by establishing a deterministic relationship (functional relationship) or a non-deterministic relationship (correlation relationship, such as a data regression analysis method and an artificial neural network method) among related variables. The invention adopts the 'causal' relationship prediction as the main part, takes time sequence into consideration, grasps the main influence factors of the gas consumption of the blast furnace hot blast stove, establishes a blast furnace hot blast stove gas consumption prediction model, can predict the gas consumption of the blast furnace hot blast stove in the future with high precision, and lays a technical foundation for realizing industrial application.
Disclosure of Invention
The invention provides a method for predicting the gas consumption of a blast furnace hot blast stove with high precision in order to solve the technical problems in the background technology, and aims to predict the gas consumption of the blast furnace hot blast stove in the iron-making production process in advance and provide technical support for realizing dynamic gas optimization scheduling of iron and steel enterprises.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for predicting the gas consumption of blast furnace hot blast stove with high precision comprises the following steps:
step 1: establishing a model for predicting gas consumption of single hot blast furnace
The method is based on a blast furnace and hot blast furnace production plan and equipment maintenance plan, and establishes a single hot blast furnace gas consumption prediction model under various working conditions of the blast furnace according to hot blast furnace burning and air supply system and by referring to hot blast furnace heat balance test analysis report data, wherein the blast furnace working conditions comprise: normal production, wind reduction, damping down and reblowing working conditions;
step 1.1: gas consumption prediction model for establishing normal production working conditions of blast furnace and hot-blast stove
When the blast furnace is normally produced, the combustion period, the furnace closing period, the furnace changing period and the air supply period of the hot blast furnace are relatively stable, and in order to improve the prediction precision, the combustion period of the hot blast furnace is subdivided into: a rapid heating period, a vault temperature heat preservation period and a smoke exhaust temperature control period are respectively predicted; the mathematical model expression is as follows:
in the formula: b isi(t) gas flow (nm) for the prediction time period of the ith hot-blast stove3/h)；
t0、thRespectively a prediction starting time (h) and a prediction ending time (h);
k is gas heat value correction coefficient, and K is Qdt/Qd(t)…(2)
Qdt、Qd(t) gas heat values (kj/m) of the last prediction period and the prediction period respectively3)；
fi(t): when the working condition is normal, the time is taken as a piecewise function of the independent variable;
1.1.1 a rapid heating period, which is a combustion initial period, wherein the time of the period is the average value of historical statistical values;
fi(t)＝αBmax…(3)；
1.1.2 vault temperature heat preservation period, when the vault temperature reaches 1300-1400 ℃, entering the control period, and taking the average value of historical statistical values in the period;
fi(t)＝αBbwn…(4)；
1.1.3 a smoke exhaust temperature control period, wherein when the smoke exhaust temperature reaches 320-;
fi(t)＝αBmin…(5)；
1.1.4 furnace closing and furnace changing period, when the exhaust temperature reaches 380-;
fi(t)＝0…(6)；
1.1.5 air supply period, wherein the time of the period is the average value of historical statistical values;
fi(t)＝0…(7)；
in the above formula: b ismax: is the average gas amount (nm) in the initial combustion statistics3/h)；
Bbwn: is the average gas amount (nm) in the vault temperature heat preservation period statistics3/h)；
Bmin: in the statistics of the exhaust gas temperature control periodAverage gas amount (nm)3/h)；
α: the ratio of the actual value and the statistical value of the blast furnace gas pipe network pressure is obtained;
1.1.6 blast furnace hot blast stove normal production working condition gas consumption dynamic correction
(1) Combustion air and gas preheating temperature change correction
ΔBk(t)＝[(Ck2×tk2﹣Ck1×tk1)×vk(t﹣1)]/Qd(t)…(8)；
ΔBm(t)＝[(Cm2×tm2﹣Cm1×tm1)×Bi(t﹣1)]/Qd(t)…(9)；
In the formula: delta Bk(t)、ΔBm(t): respectively as the correction values of preheating temperature changes (nm) of combustion air and coal gas in the t period3/h)；
Ck2、Cm2: specific heat (kj/m) of combustion air and coal gas in t period3℃)；
Ck1、Cm1: specific heat (kj/m) at historical statistical average temperature of combustion air and coal gas respectively3℃)；
tk2、tk1、tm2、tm1: respectively the time interval temperature of combustion air and coal gas and historical statistical average temperature (DEG C);
vk(t﹣1)、Bi(t-1): respectively combustion air and coal gas (t-1) time interval flow (nm)3/h)；
(2) Blast furnace hot blast stove air supply volume, wind temperature change correction
When the hot blast stove is switched from an air supply period to a combustion period, the total air volume and the average air temperature in the air supply period determine the cool degree and the hot degree of the hot blast stove in the next combustion period, namely the total air volume in the air supply period is large and the average air temperature is high, the hot blast stove in the next combustion period is relatively cool, otherwise, the hot blast stove in the next combustion period is relatively hot, and the correction models of the cool degree and the hot degree are as follows:
ΔBf(t)＝(vfs×tps﹣vft×tpt)/[η×Qd(t)]…(10)；
in the formula: delta Bf(t): gas flow correction (nm) for t period3/h)；
vfs、tps: respectively the total air volume (nm) of the previous air supply period3H) and mean wind temperature (. degree. C.);
vft、tpt: respectively the average total air volume (nm) of the air supply period in the historical statistics3H) and mean wind temperature (. degree. C.);
eta: the thermal efficiency (%) of the hot blast stove is respectively obtained from the thermal balance test data of each hot blast stove;
the dynamic gas consumption prediction model under the normal working condition of the single hot blast stove is obtained from the following steps:
step 1.2: establishing a coal gas consumption prediction model under the abnormal production working conditions of the blast furnace hot blast stove, wherein the abnormal production working conditions comprise blast furnace air reduction, damping down, reblowing, furnace shutdown and hot blast stove overhaul and heat preservation;
for the working condition of reducing or recovering the blast furnace, predicting a new furnace changing period and time according to the air reducing amount or the air recovering amount, the air supply temperature and the air supply time, so that the hot blast furnace in the original combustion state can prolong the combustion period or furnace closing time;
for the working condition of damping down the blast furnace, the working condition of damping down the blast furnace comprises the working condition of stopping production of the blast furnace and overhauling the hot blast furnace, the damping down time of the blast furnace is limited by 7 days, the short-term damping down is carried out when the damping down time is less than 7 days, and the long-term damping down is carried out when the damping down time is more than or equal to 7 days; because most of the checker bricks at the vault and the upper part of the hot blast furnace are made of silica bricks, the problem of poor rapid cooling and heat shock resistance of the silica bricks is considered, the hot blast furnace is required to be subjected to heat preservation operation even if the blast furnace stops blowing or production, otherwise, the service life of the hot blast furnace is greatly influenced;
for planned short-term blast furnace damping down: before damping down, all the hot blast furnaces of the blast furnace are subjected to primary furnace burning, the vault temperature is controlled to be 1300-1350 ℃, the flue gas temperature is controlled to be 300 ℃, and the blast furnace enters a heat preservation state; when the interface temperature of the silica bricks is reduced to 650 ℃, starting to carry out secondary furnace burning, controlling the vault temperature to be 1100-1150 ℃, controlling the flue gas temperature to be below 400 ℃, and entering a heat preservation state;
for planned long-term blast furnace damping down: in the damping-down process, when the temperature of the vault of the hot blast stove is detected to be reduced to 700 ℃ or the interface temperature of the silica brick is detected to be reduced to 650 ℃, the stove burning is started, and the temperature of the waste gas generated in the first stove burning is controlled to be 300 ℃; controlling the temperature of the waste gas of the second furnace burning to be 350 ℃; controlling the temperature of the third furnace burning waste gas at the upper limit of 400 ℃; if the temperature of the waste gas is not controlled, stopping burning the furnace, if a back blowing condition is met, carrying out back blowing by using cold air of a combustion fan, and if the back blowing condition is not met, opening compressed air to cool the grate and the support columns thereof so as to enable the temperature of the furnace top to be higher than 700 ℃ or the temperature of the silicon brick interface to be higher than 650 ℃; respectively establishing a blast furnace air reduction, re-air, damping down and hot blast stove maintenance heat preservation working condition gas consumption prediction model below;
1.2.1 blast furnace air-reducing or overfire working condition gas consumption prediction model
For the blast furnace working condition of reducing or recovering air, the air supply temperature and the total air volume of the hot blast furnace in the air supply period are assumed to be kept unchanged, the air supply time is prolonged, and the prolonging time is calculated according to the following formula:
from t × vft＝(t+Δt)×vfjCan obtain the product
Δt＝(vft/vfj─1)×t…(12)；
In the formula: t: air quantity air supply time (h) under normal working conditions;
Δ t: the air supply time difference (h) is the air supply time difference (h) between the normal working condition and the abnormal working condition;
vft、vfj: the air supply per hour (nm) of normal working condition and abnormal working condition in the air supply period3/h)；
Before the blast furnace is not recovered to the normal working condition, the combustion period of the hot blast furnace in the combustion period is prolonged by 2 times delta t time, so that the gas consumption in unit time is reduced, and the gas consumption in the whole combustion period is increased; gas consumption Bi(t) the model is calculated as:
in the formula: thj th +2 Δ t (h);
th: normal condition air supply time (h), thj: abnormal working condition air supply time (h);
k: as a gas calorific value correction factor (same as above),
Yi(t): the gas consumption of the blast furnace under the working condition of wind reduction or reblowing can be taken as the average value (nm) of historical data3/h)；
1.2.2 prediction model of gas consumption of short-term blowing down of blast furnace, namely blowing down time less than 7 days or hot blast furnace maintenance time less than 7 days
In order to ensure the service life of the silica brick checker brick, the hot blast stove is required to be insulated in the whole process and is burnt twice; the constraint conditions of the starting time of the first furnace burning are as follows: 10-30 minutes before the blast furnace is stopped, and the constraint conditions of the furnace burning end time are as follows: the vault temperature of the hot blast stove reaches 1300-1350 ℃, and the exhaust gas temperature reaches 300-350 ℃; the prediction model of the gas consumption during the furnace burning period is as follows:
Xi(t)＝αBx1…(15)；
at other times
Xi(t)＝0…(16)；
The constraint conditions of the starting time of the second time of furnace burning are as follows: the interface temperature of the silica brick is reduced to 650 ℃, and the constraint conditions of the furnace firing end time are as follows: the temperature of the vault of the hot blast stove reaches 1000-1150 ℃, and the temperature of exhaust gas reaches below 400 ℃;
Xi(t)＝αBx2…(17)；
at other times: xi(t)＝0…(18)；
In the above formula: xi(t): the method is a piecewise function taking time as an independent variable under the working conditions of short-term damping-down and long-term damping-down of the blast furnace and the maintenance of the hot blast furnace, and the following steps are carried out;
α: the ratio of the actual value and the statistical value of the blast furnace gas pipe network pressure is obtained;
k: the gas heat value correction coefficient is obtained;
Bx1、Bx2: the gas consumption of the first furnace burning and the second furnace burning during short-term damping down are respectively taken as the average value (m) of historical data3/h)；
1.2.3 prediction model of gas consumption when long-term blowing-down and blowing-down time of blast furnace is more than or equal to 7 days or when overhaul time of hot blast furnace is more than or equal to 7 days
When the temperature of the vault of the hot blast stove is reduced to 700 ℃ or the interface temperature of the silica bricks is more than 650 ℃, the stove burning is started, the stove burning ending time is controlled by the smoke exhaust temperature (300-400 ℃), and during the stove burning period: t is started0And end t ═ thThe gas consumption prediction model is as follows:
Xi(t)＝αBx3…(19)；
in the non-furnace-burning time; the gas consumption prediction model is as follows:
Xi(t)＝0…(20)；
in the above formula: b isx3: average value (m) of historical data is taken for gas consumption when the hot blast stove is heated for a long time3/h)；
Step 1.3: the single hot-blast furnace gas consumption prediction model comprises: normal production, blast furnace air reduction and re-air, and short-term and long-term blast furnace damping down;
step 2: gas consumption prediction model of single-seat combustor
When the heat value of the supplied hot blast furnace gas is lower than the specified heat value or the whole wind temperature level needs to be improved, the combustion furnace needs to be started, and the gas consumption is relatively stable; the size of the gas-liquid separator depends on the height of the heat value of the gas or the height of the wind temperature, and the statistical value of production is taken as a standard;
Bj(t)＝αBrj…(22)；
in the above formula Bj: gas consumption (nm) of jth blast furnace burner3/h)；
Brj: statistical value (nm) of gas consumption of jth blast furnace combustion furnace3/h)；
And 7: multi-blast furnace, multi-hot blast furnace and model for predicting gas consumption of combustion furnace
In the formula: bz (t): total gas consumption (nm) of hot-blast stove and combustion furnace3/h)；
m, n: the number of blast furnace seats and the number of hot blast furnace seats contained in each blast furnace are respectively;
subscripts j, I: respectively numbering a blast furnace and a hot blast furnace;
in consideration of the influence of the change in the hot blast stove gas heat value, the total gas consumption of the hot blast stove is corrected according to the following formula:
Bz(t)＝β×Bz(t-1)…(24)；
β＝Qd(t-1)/Qd(t)…(25)；
in the formula, beta: gas calorific value correction factor;
Qd(t-1)、Qd(t): the average calorific value (kj/m) of the gas in the t-1 time period and the t time period respectively3)；
And step 3: dynamic modification of prediction models
When the gas consumption of the blast furnace hot blast stove and the gas consumption of the combustion stove are initially predicted, the gas consumption of the last combustion period, the preheating temperature of air and gas, the vault temperature, the exhaust gas temperature, the blast volume of the air supply period and the air temperature are initial parameters, the mathematical model established by the method is used for initial prediction, and then dynamic correction is carried out every 10 minutes according to data acquired in real time.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a method for predicting the gas consumption of a blast furnace hot blast stove, which can predict the gas consumption of the blast furnace hot blast stove with high precision (more than or equal to 95 percent) and lays a technical foundation for realizing dynamic optimization scheduling of enterprise gas; has important effect on realizing zero diffusion of coal gas of enterprises.
Drawings
FIG. 1 is a structural view of a blast furnace hot blast stove of the present invention.
In the figure: 1-hot blast stove 2-combustion-supporting fan 3-air flow meter 4-air heat exchanger 5-thermocouple 6-air flow meter 7-combustion furnace 8-air flow meter 9-gas pipe network 10-gas flow meter 11-gas heat value instrument 12-gas heat exchanger 13-thermocouple 14-gas flow meter 15-gas flow meter 16-thermocouple 17-draught fan 18-thermocouple 19-flue gas residual oxygen analyzer-zirconia 20-chimney 21-blower 22-air flow meter 23-thermocouple 24-thermocouple 25-thermocouple 26-blast furnace 27-cold blast valve 28-vault thermocouple.
Detailed Description
The following detailed description of the present invention will be made with reference to the accompanying drawings.
As shown in FIG. 1, a blast furnace is usually provided with 3 to 4 hot blast stoves, and a two-burning one-feeding or two-burning two-feeding system is carried out. The hot blast stove (1) is in the combustion period: cold air sent by a combustion fan (2) is sent into an air heat exchanger (4) through an air flow meter (3), after the temperature is measured by a thermocouple (5), one part of the cold air is sent to a combustion furnace (7) through an air flow meter (6) for combustion supporting, and the other part of the cold air is sent to a hot blast stove (1) for combustion supporting through an air flow meter (8); coal gas is fed in from a coal gas pipe network (9), passes through a coal gas flow meter (10) and a coal gas heat value instrument (11), is preheated by a coal gas heat exchanger (12), is subjected to temperature measurement by a thermocouple (13), one part of the coal gas is fed into a combustion furnace (7) for combustion through a coal gas flow meter (14), and the other part of the coal gas is fed into a hot blast stove (1) for combustion through a coal gas flow meter (15); flue gas combusted by the hot blast stove (1) absorbs heat through internal checker bricks, is subjected to temperature measurement through a thermocouple (16) in a flue, and a part of the flue gas is sent into a combustion furnace (7) through a draught fan (17) to be mixed with combustion waste gas of the combustion furnace, is respectively sent into an air heat exchanger (4) and a coal gas heat exchanger (12) after being subjected to temperature measurement through a thermocouple (18), is subjected to oxygen content analysis through a flue gas residual oxygen analyzer-zirconium oxide (19), and is discharged through a chimney (20); the hot blast stove (1) is arranged in the air supply period: high-pressure air is sent out by an electric blower (21), is sent into a hot blast furnace (1) through an air flow meter (22) and a thermocouple (23), is heated through internal checker bricks, is subjected to temperature measurement through thermocouples (24) and (25), and is sent into a blast furnace (26), when the air supply temperature is higher than the target blast furnace air temperature upper limit, a cold air valve (27) is opened to adjust the air temperature, and when the air supply temperature reaches the blast furnace air temperature lower limit value or reaches the specified furnace change time, furnace change operation is started.
The invention is based on the blast furnace hot blast stove heat balance test, according to the blast furnace production plan (molten iron output, hot blast temperature, blast volume), the equipment maintenance plan and the judgment of the blast furnace working condition (normal production, wind reduction, damping down and re-wind), by collecting the initial vault temperature and exhaust gas temperature of each hot blast stove combustion period, the total wind volume and average wind temperature of the previous air supply period, the coal gas flow and coal gas heat value and other parameters on line, and subdividing the hot blast stove combustion period into a rapid heating period, a vault temperature heat preservation period, an exhaust gas temperature control period, a furnace closing period and a furnace changing period, respectively establishing a dynamic prediction model of the coal gas consumption of each period of a single hot blast stove. Forecasting the gas consumption of all hot blast stoves (including combustion furnaces) by summing the gas consumption of all hot blast stoves in the combustion period; in order to improve the prediction precision, parameters such as air and coal gas preheating temperature, the vault temperature of the hot blast stove, exhaust gas temperature, coal gas flow, air flow, hot air flow, coal gas pipe network pressure and the like are collected in real time, and the model parameters are dynamically corrected once every 10 minutes. The specific prediction method is as follows:
1. and carrying out heat balance test on all the hot blast stoves once every year to form a heat balance test analysis report, and establishing a database.
2. Collecting production plans and equipment maintenance plans in prediction time periods of blast furnaces and hot blast furnaces from an enterprise ERP system (or a production planning department), wherein the production plans and the equipment maintenance plans comprise: blast furnace molten iron yield, damping down and hot blast furnace heat preservation time plan.
3. Each blast furnace, combustion furnace and hot blast stove are numbered separately. For example: the 1# blast furnace comprises 1#, 2#, 3# hot blast stoves, the 2# blast furnace comprises 4#, 5#, 6# hot blast stoves, the 1# blast furnace comprises a 1# combustion furnace, and the 2# blast furnace comprises a 2# combustion furnace.
4. The method comprises the steps of collecting the tapping time and the iron yield of each blast furnace in one week before prediction (for judging the working condition change of the blast furnace) on line from a blast furnace production scheduling platform; collecting the change curves of blast volume, hot air temperature and gas pipe network pressure of each blast furnace along with time; respectively collecting a coal gas consumption, a combustion-supporting air consumption, an air preheating temperature, a coal gas preheating temperature, a vault crown temperature, a smoke exhaust temperature, a coal gas heat value, a time-varying curve (for dynamic correction) of smoke components (zirconia detection data), furnace changing time and air supply time (key time nodes) of each hot blast furnace in a combustion period by taking the blast furnace as a unit; and collecting the change curves of the air quantity, the air temperature and the vault temperature of each hot blast stove in the air supply period along with time. The data collected above must be on the same time axis.
5. Establishing a model for predicting gas consumption of single hot blast furnace
A blast furnace and hot blast furnace production plan and an equipment maintenance plan are used as a support, a single hot blast furnace gas consumption prediction model under various working conditions of the blast furnace is established according to a hot blast furnace burning and air supply system and by referring to hot blast furnace heat balance test analysis report data (wherein the blast furnace working conditions comprise normal production, wind reduction, damping down and reblowing working conditions).
5.1 establishing a gas consumption prediction model for normal production conditions of blast furnace and hot-blast stove
When the blast furnace is normally produced, the combustion period, the furnace closing period, the furnace changing period and the air supply period of the hot blast furnace are relatively stable, and in order to improve the prediction precision, the combustion period of the hot blast furnace is subdivided into: a rapid heating period, a vault temperature heat preservation period and a smoke exhaust temperature control period, and predicting respectively. The mathematical model expression is as follows:
in the formula: b isi(t) gas flow (nm) for the prediction time period of the ith hot-blast stove3/h)；
t0、thRespectively a prediction starting time (h) and a prediction ending time (h);
k is gas heat value correction coefficient, and K is Qdt/Qd(t)…(2)；
Qdt、Qd(t) gas heat values (kj/m) of the last prediction period and the prediction period respectively3)；
fi(t): under the normal working condition, the working condition is that,a piecewise function with time as an argument.
5.1.1 fast heating period (initial period of combustion, average of historical statistics)
fi(t)＝αBmax…(3)；
5.1.2 vault temperature heat preservation period (when the vault temperature reaches 1300-1400 ℃, the control period is entered, and the period takes the average value of historical statistics)
fi(t)＝αBbwn…(4)；
5.1.3 a smoke exhaust temperature control period (when the smoke exhaust temperature reaches 320-,
fi(t)＝αBmin…(5)；
5.1.4 furnace closing and furnace changing period (entering the control period when the exhaust temperature reaches 380-,
fi(t)＝0…(6)；
5.1.5 air supply period (average of historical statistics during this period)
fi(t)＝0…(7)；
In the above formula: b ismax: is the average gas amount (nm) in the initial combustion statistics3/h)；
Bbwn: is the average gas amount (nm) in the vault temperature heat preservation period statistics3/h)；
Bmin: is the average gas quantity (nm) in the statistics of the exhaust gas temperature control period3/h)；
α: is the ratio of the actual value and the statistical value of the blast furnace gas pipe network pressure.
Dynamic correction of gas consumption in normal production condition of blast furnace hot blast stove
(1) Combustion air and gas preheating temperature change correction
ΔBk(t)＝[(Ck2×tk2﹣Ck1×tk1)×vk(t﹣1)]/Qd(t)…(8)；
ΔBm(t)＝[(Cm2×tm2﹣Cm1×tm1)×Bi(t﹣1)]/Qd(t)…(9)；
In the formula: delta Bk(t)、ΔBm(t): respectively as the correction values of preheating temperature changes (nm) of combustion air and coal gas in the t period3/h)；
Ck2、Cm2: specific heat (kj/m) of combustion air and coal gas in t period3℃)；
Ck1、Cm1: specific heat (kj/m) at historical statistical average temperature of combustion air and coal gas respectively3℃)；
tk2、tk1、tm2、tm1: respectively the time interval temperature of combustion air and coal gas and historical statistical average temperature (DEG C);
vk(t﹣1)、Bi(t-1): respectively combustion air and coal gas (t-1) time interval flow (nm)3/h)。
(2) Blast furnace hot blast stove air supply volume, wind temperature change correction
When the hot blast stove is switched from an air supply period to a combustion period, the total air volume and the average air temperature in the air supply period determine the cool degree and the hot degree of the hot blast stove in the next combustion period, namely the total air volume in the air supply period is large and the average air temperature is high, the hot blast stove in the next combustion period is relatively cool, otherwise, the hot blast stove in the next combustion period is relatively hot, and the correction models of the cool degree and the hot degree are as follows:
ΔBf(t)＝(vfs×tps﹣vft×tpt)/[η×Qd(t)]…(10)；
in the formula: delta Bf(t): gas flow correction (nm) for t period3/h)；
vfs、tps: respectively the total air volume (nm) of the previous air supply period3H) and mean wind temperature (. degree. C.);
vft、tpt: respectively the average total air volume (nm) of the air supply period in the historical statistics3H) and mean wind temperature (. degree. C.);
eta: the thermal efficiency (%) of the hot blast stove is respectively obtained from the thermal balance test data of each hot blast stove.
The dynamic gas consumption prediction model under the normal working condition of the single hot blast stove is obtained from the following steps:
5.2 establishing a model for predicting the gas consumption of the blast furnace hot blast stove under abnormal production conditions (including blast furnace air reduction, damping down, reblowing, blowing out and hot blast stove maintenance and heat preservation)
For the working condition of blast furnace air reduction or air recovery, the new furnace changing period and time can be predicted according to the air reduction amount or air recovery amount, the air supply temperature and the air supply time, so that the hot blast furnace in the original combustion state can prolong the combustion period or the furnace smoldering time.
For the working condition of blast furnace damping down (including blast furnace production stopping and hot blast furnace maintenance), the damping down time of the blast furnace is limited by 7 days, short-term damping down is carried out in less than 7 days, and long-term damping down is carried out in more than or equal to 7 days. Because the silica brick material is mostly selected for the checker bricks at the vault and the upper part of the hot blast stove, the problem of poor rapid cooling and heat shock resistance of the silica brick material is considered, even if the blast furnace stops blowing or stops production, the hot blast stove is required to be subjected to heat preservation operation, otherwise, the service life of the hot blast stove is greatly influenced.
For planned short-term blast furnace damping down: before damping down, all the hot blast furnaces of the blast furnace are subjected to primary furnace burning, the vault temperature is controlled to be 1300-1350 ℃, the flue gas temperature is controlled to be 300 ℃, and the blast furnace enters a heat preservation state; when the interface temperature of the silica brick is reduced to 650 ℃, the secondary furnace burning is started, the vault temperature is controlled to be 1100-1150 ℃, the flue gas temperature is controlled to be below 400 ℃, and the furnace enters a heat preservation state.
For planned long-term blast furnace damping down: in the damping-down process, when the temperature of the vault of the hot blast stove is detected to be reduced to 700 ℃ or the interface temperature of the silica brick is detected to be reduced to 650 ℃, the stove burning is started, and the temperature of the waste gas generated in the first stove burning is controlled to be 300 ℃; controlling the temperature of the waste gas of the second furnace burning to be 350 ℃; controlling the temperature of the third furnace burning waste gas at 400 ℃ (upper limit); if the temperature of the waste gas is not controlled, stopping burning the furnace, if a back blowing condition is met, back blowing is carried out by using cold air of a combustion fan, and if the back blowing condition is not met, compressed air can be opened to cool the grate and the support columns thereof, so that the temperature of the furnace top is higher than 700 ℃ or the interface temperature of the silica bricks is higher than 650 ℃. And respectively establishing a blast furnace air reduction, re-air, damping down and hot blast stove maintenance and heat preservation working condition gas consumption prediction model.
5.2.1 blast furnace air-reducing or overfire working condition gas consumption prediction model
For the blast furnace working condition of reducing or recovering air, the air supply temperature and the total air volume of the hot blast furnace in the air supply period are assumed to be kept unchanged, the air supply time is prolonged, and the prolonging time is calculated according to the following formula:
from t × vft＝(t+Δt)×vfjThe following can be obtained:
Δt＝(vft/vfj─1)×t…(12)；
in the formula: t: air quantity air supply time (h) under normal working conditions;
Δ t: the air supply time difference (h) is the air supply time difference (h) between the normal working condition and the abnormal working condition;
vft、vfj: the air supply per hour (nm) of normal working condition and abnormal working condition in the air supply period3/h)。
Before the blast furnace is not restored to the normal working condition, the combustion period of the hot blast stove in the combustion period is prolonged by 2 times delta t, so that the gas consumption per unit time is reduced, and the gas consumption in the whole combustion period is increased. Gas consumption Bi(t) the model can be calculated as follows:
in the formula: thj th +2 Δ t (h);
th: normal condition air supply time (h), thj: the air supply time (h) under the abnormal working condition,
k: as a gas calorific value correction factor (same as above),
Yi(t): the gas consumption of the blast furnace under the working condition of wind reduction or reblowing can be taken as the average value (nm) of historical data3/h)。
5.2.2 blast furnace short-term damping down (damping down time is less than 7 days) or hot-blast furnace maintenance time is less than 7 days gas consumption prediction model
In order to ensure the service life of the silica brick checker brick, the hot blast stove needs to be insulated in the whole process and is burnt twice. The constraint conditions of the starting time of the first furnace burning are as follows: 10-30 minutes before the blast furnace is stopped, and the constraint conditions of the furnace burning end time are as follows: the vault temperature of the hot blast stove reaches 1300-1350 ℃, and the exhaust gas temperature reaches 300-350 ℃. The prediction model of the gas consumption during the furnace burning period is as follows:
Xi(t)＝αBx1…(15)；
at other times
Xi(t)＝0…(16)；
The constraint conditions of the starting time of the second time of furnace burning are as follows: the interface temperature of the silica brick is reduced to 650 ℃, and the constraint conditions of the furnace firing end time are as follows: the vault temperature of the hot blast stove reaches 1000-1150 ℃, and the exhaust gas temperature reaches below 400 ℃.
Xi(t)＝αBx2…(17)；
At other times:
Xi(t)＝0…(18)；
in the above formula, Xi(t): under the working condition of blast furnace damping down (including short-term damping down, long-term damping down and hot blast stove maintenance), the method takes time as a piecewise function of an independent variable (the same below);
α: the ratio of the actual value and the statistical value of the blast furnace gas pipe network pressure (the same as above);
k: the gas calorific value correction coefficient (same as above);
Bx1、Bx2: the gas consumption of the first furnace burning and the second furnace burning during short-term damping down are respectively taken as the average value (m) of historical data3/h)。
5.2.3 prediction model of gas consumption when blast furnace has long-term damping down (damping down time is more than or equal to 7 days) or when hot-blast furnace maintenance time is more than or equal to 7 days
When the temperature of the vault of the hot blast stove is reduced to 700 ℃ or the interface temperature of the silica bricks is more than 650 ℃, the stove burning is started, and the temperature of the exhaust gas (300-400 ℃) is controlledEnd of furnace firing period (beginning t ═ t)0And end t ═ th) The gas consumption prediction model is as follows:
Xi(t)＝αBx3…(19)；
in the non-furnace-burning time; the gas consumption prediction model is as follows:
Xi(t)＝0…(20)；
in the above formula: b isx3: average value (m) of historical data is taken for gas consumption when the hot blast stove is heated for a long time3/h)。
5.3 prediction model of gas consumption of single-seat hot blast stove (comprising four working conditions of normal production, blast furnace air reduction and reblowing and short-term and long-term damping down of blast furnace)
6. Gas consumption prediction model of single-seat combustor
When the heat value of the supplied hot blast furnace gas is lower than the specified heat value or the whole wind temperature level needs to be improved, the combustion furnace needs to be started, and the gas consumption is relatively stable. The size of the gas-liquid separator depends on the heat value of the gas or the wind temperature, and the production statistics value is taken as the standard.
Bj(t)＝αBrj…(22)；
In the above formula Bj: gas consumption (nm) of jth blast furnace burner3/h)，
Brj: statistical value (nm) of gas consumption of jth blast furnace combustion furnace3/h)，
7. Multi-blast furnace, multi-hot blast furnace and model for predicting gas consumption of combustion furnace
In the formula: bz (t): total gas consumption (nm) of hot-blast stove and combustion furnace3/h)；
m, n: the number of blast furnace seats and the number of hot blast furnace seats contained in each blast furnace are respectively;
subscripts j, I: and numbering the blast furnace and the hot blast stove respectively.
In consideration of the influence of the change in the hot blast stove gas heat value, the total gas consumption of the hot blast stove is corrected according to the following formula:
Bz(t)＝β×Bz(t-1)…(24)；
β＝Qd(t-1)/Qd(t)…(25)；
in the formula, beta: gas calorific value correction factor;
Qd(t-1)、Qd(t): the average calorific value (kj/m) of the gas in the t-1 time period and the t time period respectively3)。
8. Dynamic modification of prediction models
When the gas consumption of the blast furnace hot blast stove and the gas consumption of the combustion stove are initially predicted, the gas consumption of the last combustion period, the preheating temperature of air and gas, the vault temperature, the exhaust gas temperature, the blast volume of the air supply period and the air temperature are initial parameters, the mathematical model established by the method is used for initial prediction, and then dynamic correction is carried out every 10 minutes according to data acquired in real time.
As shown in fig. 1, the present invention is directed to the following features of the periodic operation of the hot blast stove:
1) the hot blast stove (1) is in the combustion period: the cold air sent by the combustion fan (2) is measured by the flow meter (3) and then sent to the air heat exchanger (4), after the temperature of the preheated air is measured by the thermocouple (5), one part of the preheated air is measured by the air flow meter (6) and then sent to the combustion furnace (7) for combustion supporting, and the other part of the preheated air is measured by the air flow meter (8) and then sent to the hot blast stove (1) for combustion supporting. Coal gas is fed from a coal gas pipe network (9), is measured by a coal gas flow meter (10) and is subjected to heat value detection by a coal gas heat value meter (11), is preheated by a coal gas heat exchanger (12), is subjected to temperature measurement by a thermocouple (13), and then is fed into a combustion furnace (7) for combustion after being measured by a coal gas flow meter (14) (when the coal gas heat value is lower than a specified heat value or the blast furnace requires high air temperature and cannot be met by the air and coal gas heat exchanger alone, the combustion furnace needs to be started, otherwise, the combustion furnace does not need to be started), and then is fed into a hot blast furnace (1) for combustion after being measured by a coal gas flow meter (15; gas is consumed in the combustion period, and gas is not consumed in the air supply period. The technical contribution of the invention lies in that: the method comprises the steps of subdividing a combustion period into a rapid heating period (the initial stage of burning), a vault temperature heat preservation period (the period is entered when the temperature of a thermocouple (28) at the vault of the hot blast stove reaches a specified temperature), a smoke exhaust temperature control period (the period is entered when the temperature of a thermocouple (16) at a smoke exhaust flue of the hot blast stove reaches a specified temperature), a furnace closing period and a furnace changing period, and respectively establishing a gas consumption prediction model of each period according to different gas consumption of different periods.
2) The flue gas after the combustion of the hot blast stove (1) absorbs heat through the checker bricks inside, the temperature is measured through a thermocouple (16) in a flue, one part of the flue gas is sent into a combustion furnace (7) by a draught fan (17) to be mixed with combustion waste gas of the combustion furnace, the flue gas is respectively sent into an air heat exchanger (4) and a coal gas heat exchanger (12) after the temperature is measured through a thermocouple (18), the oxygen content of the flue gas is detected through a residual oxygen analyzer-zirconia (19) of the flue gas, and then the flue gas is discharged through a chimney (20). The hot blast stove (1) is arranged in the air supply period: high-pressure air is sent out by an electric blower (21), is measured by a flow meter (22), is sent into a hot blast furnace (1) after being measured by a thermocouple (23), is heated by lattice bricks inside the hot blast furnace, is sent into a blast furnace (26) after being measured by thermocouples (24) and (25), and is adjusted by opening a cold air valve (27) when the air supply temperature is higher than the target upper limit of the blast furnace air temperature. And when the air supply temperature reaches the blast furnace air temperature limit value or reaches the specified furnace changing time, the furnace changing operation is started. After the furnace is changed, the total air volume and the average air temperature in the air supply period are used as initial conditions for judging the cold and hot states in the next combustion period.
The above embodiments are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of the present invention is not limited to the above embodiments. The methods used in the above examples are conventional methods unless otherwise specified.
Claims (1)
1. A method for predicting the gas consumption of blast furnace hot blast stove with high precision is characterized by comprising the following steps:
step 1: establishing a model for predicting gas consumption of single hot blast furnace
The method is based on a blast furnace and hot blast furnace production plan and equipment maintenance plan, and establishes a single hot blast furnace gas consumption prediction model under various working conditions of the blast furnace according to hot blast furnace burning and air supply system and by referring to hot blast furnace heat balance test analysis report data, wherein the blast furnace working conditions comprise: normal production, wind reduction, damping down and reblowing working conditions;
step 1.1: gas consumption prediction model for establishing normal production working conditions of blast furnace and hot-blast stove
When the blast furnace is normally produced, the combustion period, the furnace closing period, the furnace changing period and the air supply period of the hot blast furnace are relatively stable, and in order to improve the prediction precision, the combustion period of the hot blast furnace is subdivided into: a rapid heating period, a vault temperature heat preservation period and a smoke exhaust temperature control period are respectively predicted; the mathematical model expression is as follows:
in the formula: b isi(t) gas flow (nm) for the prediction time period of the ith hot-blast stove3/h)；
t0、thRespectively a prediction starting time (h) and a prediction ending time (h);
k is gas heat value correction coefficient, and K is Qdt/Qd(t)…(2)
Qdt、Qd(t) gas heat values (kj/m) of the last prediction period and the prediction period respectively3)；
fi(t): when the working condition is normal, the time is taken as a piecewise function of the independent variable;
1.1.1 a rapid heating period, which is a combustion initial period, wherein the time of the period is the average value of historical statistical values;
fi(t)＝αBmax…(3)；
1.1.2 vault temperature heat preservation period, when the vault temperature reaches 1300-1400 ℃, entering the control period, and taking the average value of historical statistical values in the period;
fi(t)＝αBbwn…(4)；
1.1.3 a smoke exhaust temperature control period, wherein when the smoke exhaust temperature reaches 320-;
fi(t)＝αBmin…(5)；
1.1.4 furnace closing and furnace changing period, when the exhaust temperature reaches 380-;
fi(t)＝0…(6)；
1.1.5 air supply period, wherein the time of the period is the average value of historical statistical values;
fi(t)＝0…(7)；
in the above formula: b ismax: is the average gas amount (nm) in the initial combustion statistics3/h)；
Bbwn: is the average gas amount (nm) in the vault temperature heat preservation period statistics3/h)；
Bmin: is the average gas quantity (nm) in the statistics of the exhaust gas temperature control period3/h)；
α: the ratio of the actual value and the statistical value of the blast furnace gas pipe network pressure is obtained;
1.1.6 blast furnace hot blast stove normal production working condition gas consumption dynamic correction
(1) Combustion air and gas preheating temperature change correction
ΔBk(t)＝[(Ck2×tk2﹣Ck1×tk1)×vk(t﹣1)]/Qd(t)…(8)；
ΔBm(t)＝[(Cm2×tm2﹣Cm1×tm1)×Bi(t﹣1)]/Qd(t)…(9)；
In the formula: delta Bk(t)、ΔBm(t): respectively as the correction values of preheating temperature changes (nm) of combustion air and coal gas in the t period3/h)；
Ck2、Cm2: specific heat (kj/m) of combustion air and coal gas in t period3℃)；
Ck1、Cm1: specific heat (kj/m) at historical statistical average temperature of combustion air and coal gas respectively3℃)；
tk2、tk1、tm2、tm1: respectively the time interval temperature of combustion air and coal gas and historical statistical average temperature (DEG C);
vk(t﹣1)、Bi(t-1): respectively combustion air and coal gas (t-1) time interval flow (nm)3/h)；
(2) Blast furnace hot blast stove air supply volume, wind temperature change correction
When the hot blast stove is switched from an air supply period to a combustion period, the total air volume and the average air temperature in the air supply period determine the cool degree and the hot degree of the hot blast stove in the next combustion period, namely the total air volume in the air supply period is large and the average air temperature is high, the hot blast stove in the next combustion period is relatively cool, otherwise, the hot blast stove in the next combustion period is relatively hot, and the correction models of the cool degree and the hot degree are as follows:
ΔBf(t)＝(vfs×tps﹣vft×tpt)/[η×Qd(t)]…(10)；
in the formula: delta Bf(t): gas flow correction (nm) for t period3/h)；
vfs、tps: respectively the total air volume (nm) of the previous air supply period3H) and mean wind temperature (. degree. C.);
vft、tpt: respectively the average total air volume (nm) of the air supply period in the historical statistics3H) and mean wind temperature (. degree. C.);
eta: the thermal efficiency (%) of the hot blast stove is respectively obtained from the thermal balance test data of each hot blast stove;
the dynamic gas consumption prediction model under the normal working condition of the single hot blast stove is obtained from the following steps:
step 1.2: establishing a coal gas consumption prediction model under the abnormal production working conditions of the blast furnace hot blast stove, wherein the abnormal production working conditions comprise blast furnace air reduction, damping down, reblowing, furnace shutdown and hot blast stove overhaul and heat preservation;
for the working condition of reducing or recovering the blast furnace, predicting a new furnace changing period and time according to the air reducing amount or the air recovering amount, the air supply temperature and the air supply time, so that the hot blast furnace in the original combustion state can prolong the combustion period or furnace closing time;
for the working condition of damping down the blast furnace, the working condition of damping down the blast furnace comprises the working condition of stopping production of the blast furnace and overhauling the hot blast furnace, the damping down time of the blast furnace is limited by 7 days, the short-term damping down is carried out when the damping down time is less than 7 days, and the long-term damping down is carried out when the damping down time is more than or equal to 7 days; because most of the checker bricks at the vault and the upper part of the hot blast furnace are made of silica bricks, the problem of poor rapid cooling and heat shock resistance of the silica bricks is considered, the hot blast furnace is required to be subjected to heat preservation operation even if the blast furnace stops blowing or production, otherwise, the service life of the hot blast furnace is greatly influenced;
for planned short-term blast furnace damping down: before damping down, all the hot blast furnaces of the blast furnace are subjected to primary furnace burning, the vault temperature is controlled to be 1300-1350 ℃, the flue gas temperature is controlled to be 300 ℃, and the blast furnace enters a heat preservation state; when the interface temperature of the silica bricks is reduced to 650 ℃, starting to carry out secondary furnace burning, controlling the vault temperature to be 1100-1150 ℃, controlling the flue gas temperature to be below 400 ℃, and entering a heat preservation state;
for planned long-term blast furnace damping down: in the damping-down process, when the temperature of the vault of the hot blast stove is detected to be reduced to 700 ℃ or the interface temperature of the silica brick is detected to be reduced to 650 ℃, the stove burning is started, and the temperature of the waste gas generated in the first stove burning is controlled to be 300 ℃; controlling the temperature of the waste gas of the second furnace burning to be 350 ℃; controlling the temperature of the third furnace burning waste gas at the upper limit of 400 ℃; if the temperature of the waste gas is not controlled, stopping burning the furnace, if a back blowing condition is met, carrying out back blowing by using cold air of a combustion fan, and if the back blowing condition is not met, opening compressed air to cool the grate and the support columns thereof so as to enable the temperature of the furnace top to be higher than 700 ℃ or the temperature of the silicon brick interface to be higher than 650 ℃; respectively establishing a blast furnace air reduction, re-air, damping down and hot blast stove maintenance heat preservation working condition gas consumption prediction model below;
1.2.1 blast furnace air-reducing or overfire working condition gas consumption prediction model
For the blast furnace working condition of reducing or recovering air, the air supply temperature and the total air volume of the hot blast furnace in the air supply period are assumed to be kept unchanged, the air supply time is prolonged, and the prolonging time is calculated according to the following formula:
from t × vft＝(t+Δt)×vfjCan obtain the product
Δt＝(vft/vfj─1)×t…(12)；
In the formula: t: air quantity air supply time (h) under normal working conditions;
Δ t: the air supply time difference (h) is the air supply time difference (h) between the normal working condition and the abnormal working condition;
vft、vfj: the air supply per hour (nm) of normal working condition and abnormal working condition in the air supply period3/h)；
Before the blast furnace is not recovered to the normal working condition, the combustion period of the hot blast furnace in the combustion period is prolonged by 2 times delta t time, so that the gas consumption in unit time is reduced, and the gas consumption in the whole combustion period is increased; gas consumption Bi(t) the model is calculated as:
in the formula: thj th +2 Δ t (h);
th: normal condition air supply time (h), thj: abnormal working condition air supply time (h);
k: as a gas calorific value correction factor (same as above),
Yi(t): the gas consumption of the blast furnace under the working condition of wind reduction or reblowing can be taken as the average value (nm) of historical data3/h)；
1.2.2 prediction model of gas consumption of short-term blowing down of blast furnace, namely blowing down time less than 7 days or hot blast furnace maintenance time less than 7 days
In order to ensure the service life of the silica brick checker brick, the hot blast stove is required to be insulated in the whole process and is burnt twice; the constraint conditions of the starting time of the first furnace burning are as follows: 10-30 minutes before the blast furnace is stopped, and the constraint conditions of the furnace burning end time are as follows: the vault temperature of the hot blast stove reaches 1300-1350 ℃, and the exhaust gas temperature reaches 300-350 ℃; the prediction model of the gas consumption during the furnace burning period is as follows:
Xi(t)＝αBx1…(15)；
at other times
Xi(t)＝0…(16)；
The constraint conditions of the starting time of the second time of furnace burning are as follows: the interface temperature of the silica brick is reduced to 650 ℃, and the constraint conditions of the furnace firing end time are as follows: the temperature of the vault of the hot blast stove reaches 1000-1150 ℃, and the temperature of exhaust gas reaches below 400 ℃;
Xi(t)＝αBx2…(17)；
at other times: xi(t)＝0…(18)；
In the above formula: xi(t): the method is a piecewise function taking time as an independent variable under the working conditions of short-term damping-down and long-term damping-down of the blast furnace and the maintenance of the hot blast furnace, and the following steps are carried out;
α: the ratio of the actual value and the statistical value of the blast furnace gas pipe network pressure is obtained;
k: the gas heat value correction coefficient is obtained;
Bx1、Bx2: the gas consumption of the first furnace burning and the second furnace burning during short-term damping down are respectively taken as the average value (m) of historical data3/h)；
1.2.3 prediction model of gas consumption when long-term blowing-down and blowing-down time of blast furnace is more than or equal to 7 days or when overhaul time of hot blast furnace is more than or equal to 7 days
When the temperature of the vault of the hot blast stove is reduced to 700 ℃ or the interface temperature of the silica bricks is more than 650 ℃, the stove burning is started, the stove burning ending time is controlled by the smoke exhaust temperature (300-400 ℃), and during the stove burning period: t is started0And end t ═ thThe gas consumption prediction model is as follows:
Xi(t)＝αBx3…(19)；
in the non-furnace-burning time; the gas consumption prediction model is as follows:
Xi(t)＝0…(20)；
in the above formula: b isx3: average value (m) of historical data is taken for gas consumption when the hot blast stove is heated for a long time3/h)；
Step 1.3: the single hot-blast furnace gas consumption prediction model comprises: normal production, blast furnace air reduction and re-air, and short-term and long-term blast furnace damping down;
step 2: gas consumption prediction model of single-seat combustor
When the heat value of the supplied hot blast furnace gas is lower than the specified heat value or the whole wind temperature level needs to be improved, the combustion furnace needs to be started, and the gas consumption is relatively stable; the size of the gas-liquid separator depends on the height of the heat value of the gas or the height of the wind temperature, and the statistical value of production is taken as a standard;
Bj(t)＝αBrj…(22)；
in the above formula Bj: gas consumption (nm) of jth blast furnace burner3/h)；
Brj: statistical value (nm) of gas consumption of jth blast furnace combustion furnace3/h)；
And step 3: multi-blast furnace, multi-hot blast furnace and model for predicting gas consumption of combustion furnace
In the formula: bz (t): total gas consumption (nm) of hot-blast stove and combustion furnace3/h)；
m, n: the number of blast furnace seats and the number of hot blast furnace seats contained in each blast furnace are respectively;
subscripts j, I: respectively numbering a blast furnace and a hot blast furnace;
in consideration of the influence of the change in the hot blast stove gas heat value, the total gas consumption of the hot blast stove is corrected according to the following formula:
Bz(t)＝β×Bz(t-1)…(24)；
β＝Qd(t-1)/Qd(t)…(25)；
in the formula, beta: gas calorific value correction factor;
Qd(t-1)、Qd(t): the average calorific value (kj/m) of the gas in the t-1 time period and the t time period respectively3)；
And 4, step 4: dynamic modification of prediction models
When the gas consumption of the blast furnace hot blast stove and the gas consumption of the combustion stove are initially predicted, the gas consumption of the last combustion period, the preheating temperature of air and gas, the vault temperature, the exhaust gas temperature, the blast volume of the air supply period and the air temperature are initial parameters, the mathematical model established by the method is used for initial prediction, and then dynamic correction is carried out every 10 minutes according to data acquired in real time.
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