Method for predicting steelmaking end point temperature based on steelmaking flame

Abstract

The invention relates to the technical field of online measurement of steel-making final temperature predicted by steel-making flame, and discloses a method for predicting steel-making final temperature based on steel-making flame, which comprises the following specific steps of: obtaining oxygen cumulant in a converter according to the variable quantity of oxygen cumulant in the converter; according to the oxygen accumulation amount in the converter, the smelting state in the converter is judged in combination with sonar slagging; on the basis of the heat balance principle, basic contour line temperatures under different furnace entering conditions are obtained in combination with an extended increment model; the temperature of the flame at the converter mouth is obtained through the temperature, detected by the infrared pyrometer, of the particulate matter in the flame at the converter mouth; and smooth operation is conducted on the obtained temperature of the flame at the converter mouth, and the temperature of molten steel corresponding to different flame types is obtained. Temperature data in the furnace can be obtained and analyzed in real time in a non-contact mode, parameter adjustment of the steelmaking process can be guided, and therefore the production efficiency of steelmaking and the quality of molten steel are improved, and it is ensured that the final end point temperature accurately reaches the preset standard.

Description

Technical Field

[0001] The present invention relates to the technical field of on-line measurement of the end-point temperature of steelmaking by predicting the steelmaking flame, and particularly relates to a method for predicting the end-point temperature of steelmaking based on the steelmaking flame. Background Art

[0002] The on-line dynamic measurement of the end-point temperature of converter steelmaking has always been a difficult point in the steelmaking industry. Due to the complex reactions during the steel water blowing process, in addition to the main reactions, there are also various oxidation-reduction reactions, resulting in many uncertain factors in the process. To achieve precise control of the end-point temperature of converter steelmaking, this control technology has gone through several stages such as empirical control, static control, and dynamic control. Currently, the on-line control of the end-point temperature of steelmaking still mainly relies on these three traditional methods.

[0003] The control of the end-point temperature of converter steelmaking directly affects the chemical composition, fluidity, and subsequent processing performance of the molten steel. Excessive or too low temperature will lead to quality problems or production waste. The above three traditional converter steelmaking end-point temperature controls currently in use mainly rely on manual experience and measurement tools, and it is difficult to grasp the temperature change of the molten steel in real time and accurately. Especially in the steelmaking environment with high temperature and high dust, the measurement difficulty and error are relatively large. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a method for predicting the end-point temperature of steelmaking based on the steelmaking flame, which solves the problem of difficult prediction of the end-point composition during the converter smelting and tapping processes.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A method for predicting the end-point temperature of steelmaking based on the steelmaking flame, the specific steps are as follows:

[0007] Obtain the oxygen accumulation amount in the converter according to the change amount of the oxygen accumulation amount in the converter;

[0008] Based on the oxygen accumulation amount in the converter, and combined with sonar slag melting to judge the smelting state in the converter;

[0009] Based on the principle of heat balance, combined with the extended increment model to obtain the basic contour temperature under different furnace charging conditions;

[0010] Obtain the temperature of the converter furnace mouth flame through the temperature of the particulate matter in the converter furnace mouth flame detected by an infrared pyrometer;

[0011] Perform a smoothing operation on the obtained temperature of the converter furnace mouth flame to obtain the temperature of the molten steel corresponding to different flame types.

[0012] Further, the step of obtaining the oxygen accumulation amount in the converter according to the change amount of the oxygen accumulation amount in the converter is specifically as follows:

[0013] The change in the oxygen accumulation amount in the converter is obtained by using calculation formula (1) as follows:

[0014]

[0015] where dO s is the change in the oxygen accumulation amount in the converter; is the oxygen flow rate; α i is the coefficient of oxygen generation by the solvent; β i is the coefficient of carbon dioxide generation by the solvent; W i is the amount of solvent added; i is the type of solvent; and are the amounts of hydrogen, CO, and CO 2 generated in the converter respectively;

[0016] According to the obtained change in the oxygen accumulation amount in the converter, the oxygen accumulation amount in the converter is obtained by using formula (2) as follows:

[0017] O s = ∫(dO s )dt - (K 1 ·[Si] HM + K 2 ·[Mn] HM + K 1 ·[P] HM )·[W] HM (2)

[0018] where O s is the oxygen accumulation amount in the converter, with the unit of: Nm 3 ; K 1 , K 2 and K 3 are the coefficients for the conversion of Si, Mn, and P into SiO 2 , MnO, and P 2 O 5 respectively; [Si] HM , [Mn] HM and [P] HM are the silicon, manganese, and phosphorus contents in the hot metal respectively; [W] HM is the weight of the hot metal.

[0019] Furthermore, in the determination of the smelting state in the converter based on the oxygen accumulation amount in the converter and combined with sonar slag melting, the smelting state in the converter includes:

[0020] When the oxygen accumulation amount is less than 15%, the converter is in a dry-return smelting state;

[0021] When the oxygen accumulation is greater than 25%, the converter is in a splashing smelting state;

[0022] When the oxygen accumulation is greater than 15% and less than 25%, the converter is in a normal smelting state.

[0023] Furthermore, when the converter is in a dry-return smelting state, iron oxide scale is added to the furnace;

[0024] When the converter is in a splashing smelting state, lime is added to the converter.

[0025] Furthermore, based on the principle of thermal equilibrium, combined with the extended increment model to obtain the basic contour temperature under different furnace charging conditions, the extended increment model refers to taking the changes of all factors affecting the molten steel quality during a complete time period from the start to the tapping of the same converter as a continuous process. By comparing the initial state and the target state of the previous furnace or several previous furnaces as the reference furnace of this furnace, the temperature difference between this furnace and the reference furnace is calculated using formula (3) as:

[0026] △T = A×10℃ + B×2℃ - C×35℃ / t + D×0.8℃ + E×15℃ / t (3)

[0027] In the formula, △T is the temperature difference between this furnace and the reference furnace, with the unit of ℃; when there is no slag left after slag splashing in this furnace, the value of A is taken as 0; when all the slag is left in this furnace, the value of A is taken as -3; when there is no slag splashing in this furnace, the value of A is taken as +1; B = (the silicon content of the hot metal in this furnace - the silicon content of the hot metal in the reference furnace) × 10000; C = the scrap steel amount in this furnace - the scrap steel amount in the reference furnace, with the unit of t; D = the actual temperature of the hot metal in this furnace - the actual temperature of the hot metal in the reference furnace, with the unit of ℃; E = the hot metal amount in this furnace - the hot metal amount in the reference furnace, with the unit of t.

[0028] Furthermore, by detecting the temperature of the particulate matter in the converter furnace mouth flame with an infrared pyrometer, to obtain the temperature of the converter furnace mouth flame, the infrared pyrometer selected is a two-color infrared pyrometer, and the specific steps are as follows:

[0029] Use a two-color infrared pyrometer to detect the absorption of particulate matter in the flame in the infrared ultra-short wavelength band of 800 - 1080 nm to obtain a spectrogram;

[0030] Analyze the characteristic parameters of the spectrogram through a near-infrared spectrometer to judge the structure and composition of the particulate matter;

[0031] Obtain the temperature of the particulate matter according to the structure and composition of the particulate matter;

[0032] The temperature of the particulate matter in the flame is the average temperature of the furnace mouth flame.

[0033] Furthermore, the method for predicting the steelmaking end point temperature based on the steelmaking flame also includes:

[0034] Judge whether raw materials need to be added near the end of steelmaking;

[0035] If raw materials do not need to be added, the temperature of the molten steel is the temperature of the molten steel corresponding to different flame types;

[0036] If raw materials need to be added, the temperature of the molten steel is the temperature of the molten steel corresponding to different flame types minus the temperature of the raw materials.

[0037] The beneficial effects of the present invention are as follows: This application can obtain and analyze the temperature data in the furnace in real time without contact, can guide the adjustment of steelmaking process parameters, thereby improving the production efficiency and molten steel quality of steelmaking, ensuring that the final end temperature accurately reaches the preset standard, predicting the end temperature of steelmaking by the steelmaking flame, and can accurately control the end temperature according to different steel grades, thereby improving the alloy absorption rate, reducing the consumption of iron and steel materials, and reducing the steelmaking cost. Brief Description of the Drawings

[0038] Appendix Figure 1 Schematic diagram of a two-color infrared pyrometer for detecting the temperature at the mouth of a converter;

[0039] Appendix Figure 2 Oxygen accumulation curve when the converter is in a dry-return state;

[0040] Appendix Figure 3 Oxygen accumulation curve when the converter is in a splashing state;

[0041] Appendix Figure 4 Flow chart of predicting the end temperature of steelmaking by oxygen accumulation. Detailed Embodiment

[0042] Next, in combination with the drawings and specific embodiments, the present invention will be further described:

[0043] As Figures 1 to 4 shown, a method for predicting the end temperature of steelmaking based on the steelmaking flame, the specific steps are as follows:

[0044] Obtain the oxygen accumulation in the converter according to the change amount of the oxygen accumulation in the converter;

[0045] The change amount of the oxygen accumulation in the converter is obtained by using the calculation formula (1) as:

[0046]

[0047] Among them, dO s is the change amount of the oxygen accumulation in the converter, is the oxygen flow rate; α i is the coefficient of oxygen generation by the solvent; β i is the coefficient of carbon dioxide generation by the solvent; W iis the amount of solvent added; i is the type of solvent; and are the amounts of hydrogen, CO, and CO 2 produced in the converter, respectively;

[0048] According to the change in the oxygen accumulation amount in the converter obtained, the oxygen accumulation amount in the converter is obtained using formula (2) as follows:

[0049] O s = ∫(dO s )dt - (K 1 ·[Si] HM + K 2 ·[Mn] HM + K 1 ·[P] HM )·[W] HM (2)

[0050] where O s is the oxygen accumulation amount in the converter, with the unit of: Nm 3 ; K 1 , K 2 and K 3 are the coefficients for the conversion of Si, Mn, and P into SiO 2 , MnO, and P 2 O 5 respectively; [Si] HM , [Mn] HM and [P] HM are the contents of silicon, manganese, and phosphorus in the hot metal respectively; [W] HM is the weight of the hot metal.

[0051] Based on the oxygen accumulation amount in the converter and combined with sonar slag melting, the smelting state in the converter is judged;

[0052] The oxygen accumulation amount O s in the converter during the smelting process reflects the oxygen potential of the slag to a certain extent. According to the oxygen accumulation amount O s content in the slag, the oxygen potential in the furnace is judged. The oxygen accumulation amount O s can be used as a basis for judging whether back-drying or splashing occurs in the converter.

[0053] The smelting states in the converter include:

[0054] When the oxygen accumulation amount is less than 15%, the converter is in a back-drying smelting state; at this time, the oxygen accumulation content curve in the furnace is as Figure 2 shown;

[0055] When the oxygen accumulation amount is greater than 25%, the converter is in a splashing smelting state; at this time, the oxygen accumulation content curve in the furnace is as Figure 3 shown;

[0056] When the oxygen accumulation is greater than 15% and less than 25%, the converter is in a normal smelting state.

[0057] When the converter is in a dry-return smelting state, iron oxide scale is added to the furnace.

[0058] When the converter is in a splashing smelting state, lime is added to the converter.

[0059] Generally, during the charging process, when adding 100 kg of FeO balls, the temperature will decrease by 12 °C, and when the oxygen flow rate increases by 1000 m 3 , the temperature will increase by 9 °C; when adding 100 kg of lime, the temperature will decrease by 7 °C, and when the oxygen flow rate decreases by 1000 m 3 , the temperature will decrease by 9 °C.

[0060] Based on the principle of thermal equilibrium and combined with the extended increment model, the basic contour temperature under different furnace charging conditions is obtained.

[0061] The extended increment model refers to taking the changes of all factors affecting the molten steel quality during a complete time period from the start to the tapping of the same converter as a continuous process. By comparing the initial state and the target state of the previous furnace or several previous furnaces as the reference furnace for this furnace, the temperature difference between this furnace and the reference furnace is calculated using formula (3) as:

[0062] △T = A × 10 °C + B × 2 °C - C × 35 °C / t + D × 0.8 °C + E × 15 °C / t (3)

[0063] In the formula, △T is the temperature difference between this furnace and the reference furnace, with the unit of °C; when there is no slag left after slag splashing in this furnace, the value of A is 0; when all the slag is left in this furnace, the value of A is -3; when there is no slag splashing in this furnace, the value of A is +1; B = (the silicon content of the hot metal in this furnace - the silicon content of the hot metal in the reference furnace) × 10000; C = the scrap steel amount in this furnace - the scrap steel amount in the reference furnace, with the unit of t; D = the actual temperature of the hot metal in this furnace - the actual temperature of the hot metal in the reference furnace, with the unit of °C; E = the hot metal amount in this furnace - the hot metal amount in the reference furnace, with the unit of t.

[0064] The temperature of the converter furnace mouth flame is obtained by detecting the temperature of the particulate matter in the converter furnace mouth flame with an infrared pyrometer.

[0065] The absorption of particulate matter in the flame in the infrared ultra-short wavelength band of 800 - 1080 nm is measured using a two-color infrared pyrometer to obtain a spectrogram.

[0066] The structure and composition of the particulate matter are judged by analyzing the characteristic parameters of the spectrogram with a near-infrared spectrometer.

[0067] The temperature of the particulate matter is obtained based on the structure and composition of the particulate matter.

[0068] The temperature of the particulate matter in the flame is the average temperature of the furnace mouth flame.

[0069] Based on the principle of temperature measurement at the intersection by Yokogawa Corporation of Japan, in this application, the temperature of the particulate matter in the flame is regarded as the average temperature of the furnace mouth flame.

[0070] When Yokogawa Corporation of Japan detects the temperature of the furnace mouth flame, a steel plate is placed in the flame, and the temperature of the steel plate is detected by a two-color infrared pyrometer to replace the temperature of the converter furnace mouth flame. Therefore, in this application, the temperature of the particulate matter in the flame is determined as the average temperature of the converter furnace mouth flame.

[0071] Since the vibration of the chemical bonds of substances has specific frequencies, and the vibration frequencies and intensities of different functional groups are different, a near-infrared spectrometer can be used to analyze the characteristic parameters of the spectrogram to judge the structure and composition of substances, thereby inferring the temperature of the particulate matter, and obtaining the temperature of the furnace mouth flame according to the relationship between the temperature of the particulate matter in the flame and the temperature of the furnace mouth flame.

[0072] Perform a smoothing operation on the obtained temperature of the converter furnace mouth flame to obtain the temperature of the molten steel corresponding to different flame types.

[0073] Judge whether raw materials need to be added near the end of steelmaking;

[0074] If no raw materials need to be added, the temperature of the molten steel is the temperature of the molten steel corresponding to different flame types;

[0075] If raw materials need to be added, the temperature of the molten steel is the temperature of the molten steel corresponding to different flame types minus the temperature of the raw materials.

[0076] This invention uses a two-color pyrometer to detect the temperature of the particulate matter in the converter furnace mouth flame. Different particulate matters in the flame radiate different energies. By detecting the infrared ultra-short waveband in the range of 800 - 1080 nm, the temperature of the furnace mouth flame is predicted;

[0077] This invention uses a two-color infrared pyrometer to detect the temperature of the particulate matter in the converter flame, and indirectly measures the flame temperature (average temperature) by detecting the content of particulate matter (carbon black particles, iron particles, slag particles) in the furnace mouth flame. Compared with a monochromatic pyrometer, a two-color infrared pyrometer measures by the ratio within specific two waveband ranges of an object. When there is dust, water vapor, etc., the signals measured within the two waveband ranges decrease simultaneously. After division, the ratio remains unchanged, while the temperature measured by the monochromatic pyrometer will decrease at this time; at the same time, a two-color infrared pyrometer can measure an object smaller than the field of view, while a monochromatic pyrometer cannot measure an object smaller than the field of view. In summary, use a two-color infrared pyrometer to detect the absorption of particulate matter in the flame in the infrared ultra-short waveband (800 - 1080 nm), convert the optical signal into an electrical signal, and obtain a spectrogram after processing the electrical signal through data.

[0078] To make up for the inability of the static model to capture the dynamic characteristics that change over time during the steelmaking process, based on the heat balance, an extended incremental model is introduced to perform real-time optimization of dynamic change processes such as oxygen injection and burden addition. By precisely controlling the incremental changes, the stability of the production process is maintained to handle these dynamic processes.

[0079] For those skilled in the art, according to the technical solutions and concepts described above, various corresponding changes and deformations can be made, and all these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for predicting steelmaking endpoint temperature based on steelmaking flame, characterized in that: The specific steps are: Obtaining the accumulated oxygen amount in the converter according to the change in the accumulated oxygen amount in the converter; The smelting state in the converter is judged based on the oxygen accumulation in the converter and combined with sonar slagging; Based on the heat balance principle and combined with the extended incremental model, the basic contour temperature under different furnace entry conditions is obtained; The temperature of the converter mouth flame is obtained by measuring the temperature of the particles in the converter mouth flame with an infrared pyrometer; The obtained converter mouth flame temperature is smoothed to obtain the molten steel temperature corresponding to different flame types.

2. A method for predicting steelmaking endpoint temperature based on steelmaking flame according to claim 1, characterized in that: The step of obtaining the accumulated oxygen in the converter according to the change in the accumulated oxygen in the converter is as follows: The change in oxygen accumulation in the converter is obtained using formula (1): Among them, dO s is the change in oxygen accumulation in the converter, is the oxygen flow rate; α i is the coefficient of the amount of oxygen produced by the solvent; β i W is the coefficient of solvent producing carbon dioxide; i is the amount of solvent added; i is the type of solvent; and They are the amount of hydrogen, CO and CO2 produced in the converter respectively; According to the change of the accumulated oxygen in the converter, the accumulated oxygen in the converter is obtained by using formula (2): ABOUT s =∫(dO s )dt-(K1 [Si] HM +K2 [Mn] HM +K1 [P] HM )·[IN] HM (2) Among them, O s is the accumulated oxygen in the converter, unit: Nm 3 ; K1, K2 and K3 are the conversion coefficients of Si, Mn and P into SiO2, MnO and P2O5 respectively; [Si] HM , [Mn] HM and [P] HM are the silicon, manganese and phosphorus contents in molten iron respectively; [W] HM is the weight of molten iron.

3. A method for predicting steelmaking endpoint temperature based on steelmaking flame according to claim 1, characterized in that: The smelting state in the converter is determined based on the accumulated oxygen in the converter and combined with sonar slagging, and the smelting state in the converter includes: When the accumulated oxygen is less than 15%, the converter is in a dry smelting state; When the accumulated oxygen is greater than 25%, the converter is in a splashing smelting state; When the accumulated oxygen is greater than 15% and less than 25%, the converter is in a normal smelting state.

4. A method for predicting steelmaking endpoint temperature based on steelmaking flame as claimed in claim 3, characterized in that: When the converter is in a smelting state of drying, adding iron oxide scale into the converter; When the converter is in a splashing smelting state, lime is added into the converter.

5. A method for predicting steelmaking endpoint temperature based on steelmaking flame according to claim 1, characterized in that: The extended incremental model is based on the heat balance principle and combined with the extended incremental model to obtain the basic contour temperature under different furnace entry conditions. The extended incremental model refers to the change of all factors affecting the quality of molten steel in the entire time from the beginning to the pouring of the same converter as a continuous process. By comparing the initial state and target state of the previous furnace or the previous furnaces as the reference furnace of the current furnace, the temperature difference between the current furnace and the reference furnace is calculated using formula (3): △T=A×10℃+B×2℃-C×35℃ / t+D×0.8℃+E×15℃ / t (3) In the formula, △T is the temperature difference between the present furnace and the reference furnace, in °C; when the present furnace splashes slag without leaving slag, the value of A is 0, when the present furnace leaves all slag, the value of A is -3, when the present furnace does not splash slag, the value of A is +1; B=(silicon content of molten iron in the present furnace - silicon content of molten iron in the reference furnace)×10000; C=amount of scrap steel in the present furnace - amount of scrap steel in the reference furnace, in t; D=actual temperature of molten iron in the present furnace - actual temperature of molten iron in the reference furnace, in °C; E=amount of molten iron in the present furnace - amount of molten iron in the reference furnace, in t.

6. A method for predicting steelmaking endpoint temperature based on steelmaking flame according to claim 1, characterized in that: The temperature of the converter mouth flame is obtained by detecting the temperature of the particulate matter in the converter mouth flame by an infrared pyrometer, and the specific steps are: An infrared pyrometer is used to detect and measure the absorption of particles in the flame in the infrared ultrashort wave band of 800-1080nm to obtain a spectrum. The structure and composition of the particles can be determined by analyzing the characteristic parameters of the spectrum using a near-infrared spectrometer; Obtain the temperature of the particles based on their structure and composition; The temperature of the particles in the flame is the average temperature of the furnace mouth flame.

7. A method for predicting steelmaking endpoint temperature based on steelmaking flame according to claim 6, characterized in that: The infrared pyrometer is a two-color infrared pyrometer.

8. A method for predicting steelmaking endpoint temperature based on steelmaking flame according to claim 1, characterized in that: Also includes: Determine whether raw materials need to be added near the end of steelmaking; If no raw material needs to be added, the temperature of the molten steel is the temperature of the molten steel corresponding to the different flame types; If raw materials need to be added, the temperature of the molten steel is the temperature of the molten steel corresponding to the different flame types minus the temperature of the raw materials.

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