A method for predicting the content of temperature-sensitive elements in molten iron smelted by a blast furnace

Abstract

This invention discloses a method for predicting the content of temperature-sensitive elements in molten iron produced by blast furnace smelting, belonging to the field of blast furnace ironmaking. The method includes: establishing a furnace heat index model based on the heat input before the tuyere per unit mass of pig iron and the mass of coke burned before the tuyere per unit time; calculating the furnace heat index for multiple tapping intervals based on the established furnace heat index model; fitting a relationship curve between the content of temperature-sensitive elements in molten iron and the furnace heat index based on the calculated furnace heat index for the multiple tapping intervals and the content of temperature-sensitive elements in the molten iron for the next tapping corresponding to each of the multiple tapping intervals; step 4: predicting the content of temperature-sensitive elements in subsequent molten iron based on the calculated furnace heat index and the obtained relationship curve between the content of temperature-sensitive elements in molten iron and the furnace heat index. The method provided by this invention can predict the content of temperature-sensitive elements in molten iron relatively accurately.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace ironmaking, specifically relating to a method for predicting the content of temperature-sensitive elements in molten iron produced in a blast furnace. Background Technology

[0002] Under the condition of fixed raw material quality, furnace temperature is a key indicator for measuring the blast furnace smelting status. In the Panzhihua-Xichang blast furnace smelting high-titanium vanadium-titanium magnetite, the slag-to-iron ratio is high, and the TiO2 content in the slag exceeds 20%. The TiO2 content in the slag is easily excessively reduced to form TiC, TiN, Ti(C,N), and TiCNO, which cannot be melted under blast furnace smelting conditions, leading to deterioration of slag performance and the formation of foamy slag. Research and production practice show that, under the condition of fixed TiO2 content, the reaction temperature plays a decisive role in the degree of TiO2 reduction in the slag. The higher the temperature, the easier it is for TiO2 in the slag to be reduced, and the greater the risk of blast furnace smelting. Unlike blast furnaces smelting ordinary ores, which use the Si content in the molten iron to characterize the furnace temperature, blast furnaces smelting vanadium-titanium ores use the Ti content in the molten iron as the indicator of furnace temperature.

[0003] In production practice, fluctuations in raw material quality, equipment malfunctions, and operational errors can cause the content of temperature-sensitive elements (such as Ti and Si) in molten iron to exceed the specified range, easily leading to abnormal furnace conditions and potentially causing significant economic losses. Therefore, predicting the content of temperature-sensitive elements (such as Ti and Si) in molten iron can guide blast furnace smelting. However, currently available technologies rarely offer methods for predicting the content of temperature-sensitive elements in molten iron, or the existing methods differ significantly from production practices, resulting in poor guidance for predicting the content of sensitive elements in molten iron.

[0004] Therefore, existing technologies need to be improved. Summary of the Invention

[0005] To address the problems of the prior art, this invention provides a method for predicting the content of temperature-sensitive elements in molten iron smelting in blast furnaces. This method can predict the smelting state and temperature development trend of blast furnaces, and is of guiding significance for preventing drastic fluctuations in blast furnace temperature and the resulting deterioration of furnace conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] According to the present invention, a method for predicting the content of temperature-sensitive elements in molten iron produced by blast furnace smelting is provided, comprising the following steps:

[0008] Step 1: Establish a furnace heat index model based on the heat gain in front of the tuyeres per unit mass of pig iron and the mass of coke burned in front of the tuyeres per unit time.

[0009] Step 2: Based on the furnace heat index model established in Step 1, calculate the furnace heat index for multiple tapping intervals.

[0010] Step 3: Based on the furnace heat index of multiple tapping intervals calculated in Step 2 and the content of temperature-sensitive elements in the molten iron corresponding to the next tapping interval, the relationship curve between the content of temperature-sensitive elements in the molten iron and the furnace heat index is obtained by fitting.

[0011] Step 4: Based on the relationship curve between the content of temperature-sensitive elements in molten iron and the furnace heat index obtained in Step 3, predict the content of temperature-sensitive elements in the subsequent molten iron in the blast furnace based on the calculated furnace heat index.

[0012] According to some embodiments of the present invention, the method for predicting the content of temperature-sensitive elements in blast furnace smelting iron is applicable to the prediction of Ti content and / or Si content in blast furnace smelting iron.

[0013] According to some embodiments of the present invention, in step 1, establishing a furnace heat index model based on the heat input before the tuyere obtained per unit mass of pig iron and the mass of coke burned before the tuyere per unit time includes: obtaining the mass of coke fed into the furnace per unit time corresponding to the mass of coke burned before the tuyere per unit time based on the mass of coke burned before the tuyere per unit time; and establishing a furnace heat index model based on the heat input before the tuyere obtained per unit mass of pig iron and the mass of coke fed into the furnace per unit time.

[0014] According to some embodiments of the present invention, in step 1, the furnace thermal index model is established as follows:

[0015]

[0016] Among them, K T Furnace thermal index; ΔH t The heat gain before the tuyeres per unit mass of pig iron, kJ / kg; m′ K The mass of coke fed into the furnace per unit time corresponds to the mass of coke burning in front of the tuyeres per unit time, expressed in kg / min.

[0017] According to some embodiments of the present invention, the heat input ΔH obtained per unit mass of pig iron before the tuyere is... t It is obtained based on the heat input in front of the tuyeres per unit time and the molten iron output per unit time.

[0018] According to some embodiments of the present invention, the heat input ΔH obtained per unit mass of pig iron before the tuyere is... t Calculate according to the following formula:

[0019]

[0020] Where, ΔH bThe heat gain in front of the vent per unit time, kJ / min; m t The output of molten iron per unit time is expressed in kg / min.

[0021] According to some embodiments of the present invention, the heat gain in front of the air vent per unit time is calculated according to the following formula:

[0022] ΔH b =Q C +Q b +Q M -Q 水解 -Q 喷解

[0023] Q C =(m K ·C K +m M ·C M )×9781.2

[0024] Q b =V b ·T b ·C b

[0025] Q M =m M ·σ M

[0026] Q 水解 =W·ΔH 水解

[0027] Q 喷解 =m M ·ΔH 喷解 ,

[0028] Among them, Q C Q represents the heat released per unit time when carbon burns to produce CO, expressed in kJ / min. b Q represents the physical heat carried in by the blower per unit time, expressed in kJ / min. M The physical heat introduced by the pulverized coal injection, kJ / min; Q 水解 Q represents the heat consumed by the decomposition of moisture in fuel and blower per unit time, expressed in kJ / min. 喷解 The heat consumption of fuel thermal decomposition per unit time, kJ / min; m K C represents the mass of coke burning in front of the tuyeres per unit time, expressed in kg / min. K The carbon content (%) of the coke before the tuyeres; m M C represents the mass of pulverized coal burned in front of the tuyeres per unit time, i.e., the injection rate, expressed in kg / min. M The carbon content (%) of the pulverized coal burned in front of the tuyere; V b For dry air volume, m3 / min; T b For hot air temperature, K; C b For the heat capacity of the blower air, kJ / (m 3 ·K); σ M The physical heat introduced per unit mass of injected pulverized coal is 0.917ΔT, a value taken from production practice, in kJ / kg; W is the moisture content entering the air inlet, in m³. 3 / min;ΔH 水解 The heat consumed by the decomposition of moisture entering the air vent is kJ / m 3 ;ΔH 喷解 The heat consumed by the decomposition of pulverized coal before the tuyeres is expressed in kJ / kg.

[0029] According to some embodiments of the present invention, the output of molten iron per unit time is calculated according to the following formula:

[0030] m t =m′ K ·L K ·TFe·A / B,

[0031] Where, m′ K The mass of coke fed into the furnace per unit time, expressed in kg / min, corresponds to the mass of coke burned in front of the tuyeres per unit time; L K t / t (or kg / kg) is the coke load, which is the ratio of the mass of ore to coke in each batch fed into the furnace; TFe is the iron grade of the ore fed into the furnace, %; A is the ratio of the total Fe element entering the molten iron and slag to the total Fe element entering the furnace, which is determined based on production experience; B is the Fe element content in the molten iron, which is determined based on production experience.

[0032] According to some embodiments of the present invention, the mass of coke fed into the furnace per unit time corresponding to the mass of coke burned in front of the tuyeres per unit time is calculated according to the following formula:

[0033]

[0034] Where, m′ K The mass of coke fed into the furnace per unit time, corresponding to the mass of coke burning in front of the tuyeres per unit time, is expressed in kg / min; m. K A′ represents the mass of coke burning in front of the tuyeres per unit time, in kg / min. d V′ ad and w′ tk These are the ash content, volatile matter content, and moisture content of the coke fed into the furnace, respectively, in percent; A d The ash content of the coke from the tuyere is %.

[0035] According to some embodiments of the present invention, in step 3, linear fitting is used for fitting.

[0036] By adopting the above technical solution, the present invention has the following beneficial effects:

[0037] This invention, combining the effects of pulverized coal injection on the heat supply per ton of iron and the charging speed of a blast furnace before the tuyeres, establishes a predictive model for the content of temperature-sensitive elements in molten iron, which characterizes the furnace temperature level. This model can be applied to predict the smelting state and furnace temperature level of a blast furnace. The method for predicting the content of temperature-sensitive elements in molten iron provided by this invention can accurately predict the content of temperature-sensitive elements in molten iron. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] Specific embodiments of the invention are disclosed herein as needed; however, it should be understood that the embodiments disclosed herein are merely examples of the invention that may be implemented in various alternative forms. In the following description, various operating parameters and components are described in several contemplated embodiments. These specific parameters and components are provided as examples only and are not intended to be limiting.

[0040] According to the present invention, a method for predicting the content of temperature-sensitive elements in molten iron produced by blast furnace smelting is provided, comprising the following steps: Step 1: Establishing a furnace heat index model based on the heat input before the tuyeres per unit mass of pig iron and the mass of coke burned before the tuyeres per unit time; Step 2: Calculating the furnace heat index for multiple tapping intervals according to the furnace heat index model established in Step 1; Step 3: Fitting a relationship curve between the content of temperature-sensitive elements in molten iron and the furnace heat index based on the furnace heat index for multiple tapping intervals calculated in Step 2 and the content of temperature-sensitive elements in the molten iron for the next tapping corresponding to each of the multiple tapping intervals; Step 4: Predicting the content of temperature-sensitive elements in the subsequent molten iron in the blast furnace based on the calculated furnace heat index according to the relationship curve between the content of temperature-sensitive elements in molten iron and the furnace heat index obtained in Step 3.

[0041] The term "temperature-sensitive element" refers to an element that is sensitive to furnace temperature and whose content can characterize the furnace temperature level. Examples include Si in molten iron during blast furnace smelting of ordinary ore and Ti in molten iron during blast furnace smelting of vanadium-titanium ore, as mentioned earlier. The method for predicting the content of temperature-sensitive elements in molten iron provided by this invention is applicable to predicting the Ti content in molten iron during blast furnace smelting of vanadium-titanium ore and / or the Si content in molten iron during blast furnace smelting of ordinary ore. Of course, this invention is not limited to these and can be applied to predicting the content of other temperature-sensitive elements.

[0042] In step 1 of this invention, a furnace heat index model is established based on the heat input per unit mass of pig iron before the tuyere and the mass of coke burned before the tuyere per unit time. This model aims to consider both the impact of heat input (heat input per unit mass of pig iron) on the sensitive elements in molten iron and the impact of the actual smelting process (mass of coke burned before the tuyere per unit time) on the sensitive elements. Compared to other forms of furnace heat index models, this model is more comprehensive and better reflects the actual production conditions of blast furnace smelting. For example, the furnace heat index Wu provided in the literature "Analysis of Ironmaking Calculations" by Na Shuren only considers the heat input per unit mass of molten iron, without considering the impact of the actual smelting process on the content of sensitive elements in molten iron. Document 202011004441.1 mainly predicts the Ti content in molten iron based on the blast furnace titanium load and the Si content in molten iron, which is itself a sensitive element, without calculating the heat input or considering the impact of the actual smelting process on the sensitive elements in molten iron. This invention, based on blast furnace smelting theory, first calculates the amount of pig iron per unit mass and then fully considers the impact of the actual smelting process on the content of sensitive elements in molten iron. Compared with the two documents mentioned above, it is more theoretically scientific and more closely integrated with practice. In step 1, the mass of coke burned in front of the tuyeres per unit time is the parameter for calculating the mass of pig iron per unit time, and it is also a parameter characterizing the degree of influence of the actual smelting process on the sensitive elements in molten iron. First, through this parameter, the mass of coke that has not yet participated in smelting entering the blast furnace per unit time can be obtained. Since the ratio of the mass of coke that has not yet participated in smelting entering the blast furnace per unit time to the mass of iron ore consumed is already determined, the mass of iron ore consumed per unit time can be further obtained, and thus the pig iron output per unit time can be obtained. Based on this output, the heat income in front of the tuyeres obtained per unit mass of pig iron can be obtained. Second, the more coke burned in front of the tuyeres per unit time, the faster the blast furnace smelting process and the lower the content of sensitive elements in the molten iron; conversely, the content of sensitive elements in the molten iron increases.

[0043] In some embodiments, step 1, establishing a furnace heat index model based on the heat income before the tuyere obtained per unit mass of pig iron and the mass of coke burned before the tuyere per unit time, includes: obtaining the mass of coke fed into the furnace per unit time corresponding to the mass of coke burned before the tuyere per unit time based on the mass of coke burned before the tuyere per unit time; and establishing a furnace heat index model based on the heat income before the tuyere obtained per unit mass of pig iron and the mass of coke fed into the furnace per unit time.

[0044] In some embodiments, the furnace heat index model established in step 1 can take the form of the following equation (1):

[0045]

[0046] Among them, K TFurnace thermal index; ΔH t The heat gain before the tuyeres per unit mass of pig iron, kJ / kg; m′ K The mass of coke fed into the furnace per unit time corresponds to the mass of coke burning in front of the tuyeres per unit time, expressed in kg / min.

[0047] In some embodiments, the heat gain ΔH obtained per unit mass of pig iron before the tuyeres t It can be obtained from the heat input at the tuyeres per unit time and the output of molten iron per unit time. For example, the heat input at the tuyeres per unit mass of pig iron ΔH t Calculate according to the following formula (2):

[0048]

[0049] Where, ΔH b The heat gain in front of the vent per unit time, kJ / min; m t The output of molten iron per unit time is expressed in kg / min.

[0050] In some embodiments, the heat input ΔH in front of the air vent per unit time b It can be calculated according to the following formula (3):

[0051] ΔH b =Q C +Q b +Q M -Q 水解 -Q 喷解 (3)

[0052] In formula (3):

[0053] ΔH b The heat gain in front of the vent per unit time, kJ / min;

[0054] Q C represents the heat released per unit time when carbon burns to produce CO, expressed in kJ / min.

[0055] Q b The physical heat carried in by the blower per unit time is expressed in kJ / min.

[0056] Q M The physical heat introduced by the pulverized coal injection is expressed in kJ / min.

[0057] Q 水解 The heat consumed by the decomposition of fuel and moisture in the blower per unit time, kJ / min;

[0058] Q 喷解 The heat consumption per unit time for the thermal decomposition of injected fuel is expressed in kJ / min.

[0059]

[0060] In equation (4):

[0061] m K The mass of coke burning in front of the tuyeres per unit time, in kg / min;

[0062] C K The carbon content (%) of the coke before the tuyeres;

[0063] m M The injection rate is the mass of pulverized coal burned in front of the tuyeres per unit time, expressed in kg / min.

[0064] C M The carbon content (%) of the pulverized coal burned in front of the tuyere;

[0065] 9781.2 represents the heat released when each kg of C (considering a graphitization degree of 50%) is burned to produce CO in front of the vent, in kJ / kg(C);

[0066] V b For dry blower air volume, m 3 / min;

[0067] O 2b The volumetric O2 content in dry air, %;

[0068] w t For every 1m 3 The volume content of moisture (H2O) corresponding to dry blower air, %;

[0069] w tm The mass fraction of moisture (H2O) in the pulverized coal, expressed as a percentage.

[0070] 22.4 represents the volume of one mole of gas, 22.4 L / mol;

[0071] 0.5 is the coefficient used to convert O to O2 in a unit mass of H2O;

[0072] In equation (4), w t V b O 2b It can be calculated by the following formula:

[0073]

[0074] In equation (5), 22.4 is the volume of 1 mole of gas, 22.4 L / mol; 18 is the molecular weight of water (H2O); 1000 is the molecular weight of 1 m 3 Water volume converted to liters, 1m 3 =1000L; w′ t1m is commonly used in production sites 3 Moisture content in (1000L) wet blower air, g / m 3 .

[0075]

[0076]

[0077] In equations (6) and (7):

[0078] V′ b This refers to the volume of wet blower air commonly used in production sites, including dry air, moisture, and oxygen enrichment, in meters (m). 3 / min; 0.21 is the proportion of O2 in the dry blower, 21%, and the value is taken as 0.21 in the calculation;

[0079] 60 is the unit for oxygen enrichment (m). 3 The coefficient for converting / h to minutes, 1h = 60min;

[0080] 0.99 represents the O2 content in the oxygen-rich environment, which is 99%. The value used in the calculation is 0.99.

[0081] Q b =V b ·T b ·C b (8)

[0082]

[0083] In equations (8) and (9):

[0084] T b Here, K represents the hot air temperature.

[0085] C b The heat capacity of the blower air is kJ / (mol·K);

[0086] 10 3 To measure the gas volume m 3 The coefficient for liters (L) has been converted, 1m 3 =1000L;

[0087] ΔH m,O2 ΔH m,N2 ΔH m,H2O These represent the concentrations of O2, N2, and H2O in the humid blower at blower temperature T. b Specific heat per hour, kJ / mol;

[0088] x O2 x N2 x H2O 1m respectively 3The volume of O2, N2, and H2O in a humid blower, m 3 .

[0089] The molar heat capacities at constant pressure for O2, N2, and H2O(g) are respectively:

[0090] c pm,O2 =29.96 + 4.184 × 10 -3 T - 1.57 × 10 5 T -2 J / (mol·K) (10)

[0091] c pm,N2 =27.87 + 4.28 × 10 -3 TJ / (mol·K) (11)

[0092] c pm,H2O =30.0 + 10.71 × 10 -3 T-0.33×10 5 T -2 J / (mol·K) (12)

[0093] Based on equations (10) to (12), the blower temperature T can be obtained by integrating over temperature T. b The amount of heat absorbed by 1 mol of O2, N2, and H2O:

[0094]

[0095]

[0096]

[0097] In equations (13) to (15):

[0098] 10 -3 The coefficient for converting the heat unit J / mol to kJ / mol is 1J / mol = 10. -3 kJ / mol.

[0099] Q M =m M ·σ M (16)

[0100] In equation (16):

[0101] Q M The physical heat introduced by the pulverized coal injection is expressed in kJ / min.

[0102] σ M The physical heat (kJ / kg) introduced per unit mass of injected pulverized coal is 0.917ΔT, a value determined based on production practice.

[0103] Where ΔT is the temperature difference (°C) between the pulverized coal entering the blast furnace tuyeres and the ambient temperature;

[0104]

[0105] In equation (17):

[0106] W represents the amount of water entering the air vent, m 3 / min;

[0107] ΔH 水解 The heat consumed by the decomposition of water per unit volume is ΔH 水解 =10784.4kJ / m 3 ;

[0108] 22.4 represents the volume of one mole of gas, 22.4 L / mol;

[0109] 18 is the molecular weight of water.

[0110] Q 喷解 =m M ·ΔH 喷解 =1254m M (18)

[0111] In equation (18):

[0112] Q 喷解 The heat consumption of fuel thermal decomposition per unit time is kJ / min;

[0113] m K The injection rate (or injection volume, kg / min) of pulverized coal;

[0114] ΔH 喷解 The heat loss per unit mass of pulverized coal during decomposition before the tuyeres is ΔH. 喷解 =1254kJ / kg.

[0115] Based on the above formulas (3)-(18), we obtain the following formula (19):

[0116] ΔH b =(10479.86O) 2b -5544.47w t +T b ·C b V b -(3639.39w tm +1217.32)m M (19)

[0117] In some embodiments, the iron production per unit time is m t Calculate according to the following formula (20):

[0118] m t =m′ K ·L K ·TFe·A / B (20)

[0119] in:

[0120] m′ K The mass of carbon fed into the furnace per unit time, kg / min, corresponds to the mass of coke burned in front of the tuyeres per unit time.

[0121] L K Coke load is the ratio of the mass of ore to the mass of coke in each batch fed into the furnace, expressed in t / t (or kg / kg).

[0122] TFe represents the iron grade of the ore fed into the furnace, in percent.

[0123] A is the ratio of the total amount of Fe elements entering the molten iron and slag to the total amount of Fe elements entering the furnace, which is taken as 0.985 based on production experience;

[0124] B represents the Fe content in the molten iron, which is taken as 0.946 based on production experience.

[0125] After undergoing a series of physicochemical processes, coke experiences significant carbon (C) loss and a marked increase in ash content by the time it reaches the tuyeres. By the time the coke reaches the tuyeres, it has completely lost moisture and volatile matter. Based on the mass balance and carbon balance of the coke, we can conclude:

[0126] m' K ·C' K -Δm·C Δm =m K ·C K (twenty one)

[0127] Δm=(m' K ·C' K -m K ·C K )+(m' K ·A' d -m K ·A d )+m' K ·V' ad +m' K ·w t ' k (twenty two)

[0128] From formulas (21) and (22), we can obtain:

[0129]

[0130] In formula (21)-(23):

[0131] m K The mass of coke burning in front of the tuyeres per unit time, in kg / min;

[0132] m′ K The mass of carbon fed into the furnace per unit time, kg / min, corresponds to the mass of coke burned in front of the tuyeres per unit time.

[0133] Δm is m K and m′ K The difference in mass between the two, kg / min;

[0134] C′ K and C K The carbon content (%) of the coke entering the furnace and the coke burned before the tuyeres are respectively.

[0135] C Δm The C content of Δm, in %;

[0136] A′ d V′ ad and w′ tk These are the ash content, volatile matter content, and moisture content of the coke fed into the furnace, respectively, in %;

[0137] A d The ash content of the coke from the tuyere is %.

[0138] Therefore, we can conclude that:

[0139]

[0140]

[0141] From formulas (1), (2), (19), (20), (23), and (24), we can obtain:

[0142]

[0143] In step 2 of the present invention, the furnace heat index for multiple tapping intervals is calculated according to the furnace heat index model established in step 1. This means that the furnace heat index for multiple tapping intervals is calculated according to the above formula (25).

[0144] In step 3 of this invention, based on the furnace heat index of multiple tapping intervals calculated in step 2 and the content of temperature-sensitive elements in the molten iron corresponding to the next tapping interval, a relationship curve between the content of temperature-sensitive elements in the molten iron and the furnace heat index is fitted. Specifically, this includes: under the condition of constant raw material and fuel quality, after the blast furnace completes one tapping cycle, calculating K relative to the next tapping interval. T The Ti content of the molten iron in the next test will be compared with the calculated K. TCorrespondingly, through repeated fitting, the relationship between different molten iron Ti contents and K was obtained. T The relationship curve. The more times the iron is tapped, the higher the Ti and K content of the molten iron obtained by the above method. T The more abundant the K content, the more accurate the fitting result. The molten iron Ti content and its corresponding K content are used for fitting. T This is determined based on production practice. When the fitting results change only slightly under certain conditions, adding the required Ti and K for fitting can be stopped. T The number of samples should be determined by re-fitting and predicting the data when there are significant changes in the quality of raw materials or the blast furnace operating conditions.

[0145] In some embodiments, in step 3, linear fitting is used for fitting.

[0146] This invention, combining the effects of pulverized coal injection on the heat supply per ton of iron and the charging speed of a blast furnace before the tuyeres, establishes a predictive model for the content of temperature-sensitive elements in molten iron, which characterizes the furnace temperature level. This model can be applied to predict the smelting state and furnace temperature level of a blast furnace. The method for predicting the content of temperature-sensitive elements in molten iron provided by this invention can accurately predict the content of temperature-sensitive elements in molten iron.

[0147] Specifically, this invention, by combining the effects of pulverized coal injection on the heat supply per ton of iron and the charging rate of the blast furnace before the tuyeres in vanadium-titanium ore smelting, establishes a predictive model for the Ti content in molten iron, characterizing the furnace temperature level of the vanadium-titanium ore blast furnace. This model can be applied to predict the smelting state and furnace temperature level of the vanadium-titanium ore blast furnace. Applying the method of this invention allows for the prediction of the smelting state and furnace temperature development trend of the vanadium-titanium ore blast furnace, providing guidance for preventing drastic fluctuations in furnace temperature and the resulting deterioration of furnace conditions.

[0148] The present invention will now be described in detail through specific embodiments.

[0149] Example 1

[0150] A blast furnace for smelting vanadium-titanium ore, under the conditions shown in Tables 1 and 2, can obtain five consecutive measurements of molten iron Ti content and calculate the K content before tapping. T The relationship is:

[0151] K T =1.408-1.009Ti Adjusted R 2 =0.9798 (23)

[0152] Adjusted R 2 It is a statistic that measures the goodness of fit of a linear regression model. The closer its value is to 1, the better the model fits the data.

[0153] Table 1 Chemical composition of coke and pulverized coal from a certain blast furnace

[0154] <![CDATA[C K ]]> <![CDATA[A d ]]> <![CDATA[C' K ]]> <![CDATA[A' d ]]> <![CDATA[V' ad ]]> <![CDATA[w' tk ]]> <![CDATA[c M ]]> <![CDATA[w′ t ]]> <![CDATA[w t ]]> <![CDATA[w tm ]]> 0.7 0.3 0.85 0.133 0.013 0.004 0.77 12.01 0.0152 0.78

[0155] Table 2 Operating parameters of a blast furnace

[0156]

[0157] With the data in Table 1 remaining unchanged, the average blowing rate was increased to 403.33 kg / min and the wet air volume to 4289 m³ before the next tapping. 3 / min, dry air volume 4225m³ 3 / min, air temperature 1210℃, O 2b 0.2424, L K Under the conditions of 4.53 and TFe 0.505, K is calculated according to equation (22). T The value is 1.273. According to formula (23), the predicted Ti content in the molten iron should be 0.124. After tapping the iron, the sample analysis result was 0.136, and the ratio of the error value to the measured value was 0.088.

[0158] This 6 times iron K T A linear fit was performed again with the Ti content in the molten iron, and the relationship was as follows:

[0159] K T =1.392-0.994Ti Adjusted R 2 =0.9613 (24)

[0160] By changing the number of fitted data points as described above, the fitting results can be continuously optimized to predict the Ti content in molten iron.

Claims

1. A method for predicting the content of a temperature-sensitive element in molten iron produced by a blast furnace, characterized by, Includes the following steps: Step 1: Establish a furnace heat index model based on the heat gain in front of the tuyeres per unit mass of pig iron and the mass of coke burned in front of the tuyeres per unit time. Step 2: Based on the furnace heat index model established in Step 1, calculate the furnace heat index for multiple tapping intervals respectively; Step 3: Based on the furnace heat index of multiple tapping intervals calculated in Step 2 and the content of temperature-sensitive elements in the molten iron corresponding to the next tapping interval, the relationship curve between the content of temperature-sensitive elements in the molten iron and the furnace heat index is obtained by fitting. Step 4: Based on the relationship curve between the content of temperature-sensitive elements in the molten iron and the furnace heat index obtained in Step 3, predict the content of temperature-sensitive elements in the subsequent molten iron in the blast furnace based on the calculated furnace heat index. In step 1, a furnace heat index model is established based on the heat input before the tuyere per unit mass of pig iron and the mass of coke burned before the tuyere per unit time. This includes: obtaining the mass of coke fed into the furnace per unit time corresponding to the mass of coke burned before the tuyere per unit time; and establishing a furnace heat index model based on the heat input before the tuyere per unit mass of pig iron and the mass of coke fed into the furnace per unit time. In step 1, the furnace thermal index model is established as follows: ， in, K T The furnace heat index; Δ H t The heat gain before the tuyeres per unit mass of pig iron, in kJ / kg; m′ K This represents the mass of coke fed into the furnace per unit time, corresponding to the mass of coke burning in front of the tuyeres per unit time, expressed in kg / min. The heat income before the tuyere per unit mass of pig iron obtained Δ H t The heat income before the tuyere per unit time and the yield of molten iron per unit time are calculated by the following formula: ， in, ΔH b The heat gain in front of the vent per unit time, kJ / min; m t The output of molten iron per unit time, in kg / min. The mass of coke fed into the furnace per unit time, corresponding to the mass of coke burned in front of the tuyeres per unit time, is calculated using the following formula based on the mass of coke burned in front of the tuyeres per unit time, the ash content, volatile matter and moisture content of the coke fed into the furnace, and the ash content of the coke at the tuyeres: ， in, m K The mass of coke burning in front of the tuyeres per unit time, in kg / min; A′ d , V′ ad and w′ tk These represent the ash content, volatile matter content, and moisture content of the coke fed into the furnace, respectively, % . A d The ash content of the coke from the tuyere is %.

2. The method of claim 1, wherein the temperature-sensitive element content in the molten iron produced by the blast furnace is predicted. It is applicable to the prediction of Ti content and Si content in molten iron from blast furnace smelting.

3. The method of claim 1, wherein the temperature-sensitive element content in the molten iron produced by the blast furnace is predicted based on the temperature of the molten iron produced by the blast furnace. The heat gain in front of the vent per unit time is calculated using the following formula: ， in, Q C represents the heat released per unit time when carbon burns to produce CO, expressed in kJ / min. Q b Q represents the physical heat carried in by the blower per unit time, expressed in kJ / min. M The physical heat introduced by the pulverized coal injection is expressed in kJ / min. Q 水解 The heat consumed by the decomposition of fuel and moisture in the blower per unit time, kJ / min; Q 喷解 The heat consumption of fuel thermal decomposition per unit time is kJ / min; m K The mass of coke burning in front of the tuyeres per unit time, in kg / min; C K The carbon content of the coke before the tuyeres, % m M The injection rate is the mass of pulverized coal burned in front of the tuyeres per unit time, expressed in kg / min. C M The carbon content (%) of the pulverized coal burned in front of the tuyere. V b For dry air volume, m 3 / min; T b Here, K represents the hot air temperature. C b For the heat capacity of the blower air, kJ / (m 3 •K); σ M The physical heat introduced per unit mass of injected pulverized coal is 0.917ΔT, where ΔT is the temperature difference between the pulverized coal entering the blast furnace tuyeres and the ambient temperature, expressed in kJ / kg. W is The amount of water entering the air vent, m 3 / min ； Δ H 水解 The heat consumed by the decomposition of moisture entering the air vent is kJ / m 3 ;Δ H 喷解 The heat consumed by the decomposition of pulverized coal in front of the tuyeres is expressed in kJ / kg.

4. The method of claim 1, wherein the temperature-sensitive element content in the molten iron produced by the blast furnace is predicted. The output of molten iron per unit time is calculated using the following formula: m t = m′ K ·L K ·TFe·A / B ， in, L K Coke load is the ratio of the mass of ore to the mass of coke in each batch fed into the furnace, expressed in t / t or kg / kg. TFe 1. Iron grade of the ore fed into the furnace, %; A. The ratio of the total Fe element in the molten iron and slag to the total Fe element in the furnace, determined based on production experience; B. Fe element content in the molten iron, determined based on production experience.

5. The method of claim 1, wherein the temperature-sensitive element content in the molten iron produced by the blast furnace is predicted. In step 3, linear fitting is used for the fitting process.

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