Method for indirectly measuring carbon content of molten steel based on converter flue gas big data analysis

Abstract

The invention relates to a method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis. The method comprises the following steps: S1, obtaining initial molten iron information; s2, obtaining converter flue gas component information; s3, performing experience correction on smoke components; s4, calculating the oxidation amount of each element; s5, calculating the carbon content in the molten pool; and S6, empirically correcting the carbon content in the molten pool. According to the method, real-time online analysis is carried out on the converter flue gas components in the production process of the oxygen top-blown converter for the medium-low carbon molten iron, comprehensive analysis is carried out on the molten steel components in the smelting process of the converter, and therefore forecasting of molten steel end point carbon is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of converter steelmaking, and particularly relates to a method for indirectly measuring carbon content of molten steel based on converter flue gas big data analysis. BACKGROUND

[0002] The oxygen top-blown converter is the main steelmaking method in the world today, and the main purpose of converter smelting is to obtain molten steel with qualified composition and temperature. Due to the complicated production process of converter smelting and the complex physical and chemical reactions therein, it is difficult to effectively detect the composition and temperature in the production process of the converter. Although the traditional manual sampling detection can detect the composition and temperature of the molten steel, it prolongs the smelting cycle, loses the heat in the furnace, increases the energy consumption, and increases the labor cost and material consumption.

[0003] The traditional method for measuring the carbon content of molten steel can optimize the burden structure and predict the end-point carbon of molten steel according to the initial conditions and tapping requirements, but lacks analysis of the smelting process, has low prediction accuracy, and cannot meet the actual production needs. The end-point carbon prediction model based on the sub-lance uses the sub-lance to continuously sample at the end of the converter smelting, so as to predict the end-point carbon of the molten steel, but the consumption of the sub-lance probe is large, which increases the cost of steelmaking.

[0004] Flue gas is an important by-product in the process of converter smelting, which can directly reflect the decarburization rate of the converter. According to the decarburization reaction rate, the thermodynamic and kinetic analysis of the physical and chemical reactions in the converter can be carried out to obtain the composition and temperature information in the converter. The converter dynamic model based on flue gas analysis has the characteristics of no increase in smelting time / no additional consumption / real-time online prediction / high prediction accuracy.

[0005] The traditional method for measuring the carbon content of molten steel can optimize the burden structure and predict the end-point carbon of molten steel according to the initial conditions and tapping requirements, but lacks analysis of the smelting process, has low prediction accuracy, and cannot meet the actual production needs. The end-point carbon prediction model based on the sub-lance uses the sub-lance to continuously sample at the end of the converter smelting, so as to predict the end-point carbon of the molten steel, but the consumption of the sub-lance probe is large, which increases the cost of steelmaking. SUMMARY

[0006] In view of the above problems, the present application aims to provide a method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis, which realizes the prediction of the end-point carbon of molten steel by analyzing the composition of the converter flue gas in the production process of the oxygen top-blown converter of medium and low carbon molten iron in real time and online, and comprehensively analyzing the composition of the molten steel in the converter smelting process.

[0007] The technical scheme adopted by the present application is as follows:

[0008] The application provides a method for indirectly measuring carbon content in molten steel based on converter flue gas big data analysis, which comprises the following steps: S1, obtaining initial molten iron information; S2, obtaining converter flue gas component information; S3, flue gas component experience correction; S4, calculation of oxidation amount of each element; S5, calculation of carbon content in the molten pool; and S6, experience correction of carbon content in the molten pool.

[0009] Further, in the step S1, the initial molten iron related information is obtained through a production information system related to a steelmaking plant, and the information includes initial molten iron components and temperature.

[0010] Further, in the step S2, real-time converter flue gas component information is obtained through a flue gas component online analysis system installed on a steelmaking converter, and the information includes nitrogen content, oxygen content, carbon dioxide content and carbon monoxide content.

[0011] Further, the step S3 comprises: according to the characteristics of the flue gas components related to a specific converter, experience correction is performed.

[0012]

[0013] In the formula, x O , x N , x co , are mass percentages of oxygen, nitrogen, carbon monoxide and carbon dioxide in flue gas measurement data, and T is the temperature of molten steel in the converter.

[0014] Further, the step S4 comprises:

[0015] According to nitrogen balance in the flue gas, the following formula is obtained:

[0016] F N(i) + 0.79·F 空气(i) = F 烟气(i) · N% (i)

[0017] In the formula, F N(i) , F 空气(i) , F 烟气(i) , N% (i) are percentages of nitrogen, air at the converter mouth, flue gas at the converter mouth and nitrogen in the flue gas at the moment T i ;

[0018] The air suction amount at the moment T i is obtained as follows:

[0019] F 空气(i) = (N% (i) · F 烟气(i) - F N(i) ) / 0.79

[0020] If the inhaled air is completely combusted, the amount of oxygen for the secondary combustion is:

[0021] 0.21·F 空气(i)

[0022] According to the above, the amount of flue gas after the secondary combustion of CO2 is:

[0023] CO2% (i) ·F 烟气(i) -0.21·F 空气(i)

[0024] The amount of flue gas of CO is:

[0025] CO% (i) ·F 烟气(i) -2·0.21·F 空气(i)

[0026] In the formula, CO2% (i) is the content of CO2 in the flue gas at T i ; CO% (i) is the content of CO in the flue gas at T i ;

[0027]

[0028] In the formula, CO2 is the flow of CO2 generated by the secondary combustion at T i ; a and c are constants, a = 0.2, and c = 0.75;

[0029] Therefore, the CO2 generated by the oxidation reaction between the oxygen supplied by the oxygen lance and the carbon elements in the molten pool is:

[0030]

[0031] The generated CO is:

[0032]

[0033] Further, the step S5 includes that the oxidation distribution ratio of each element in the molten pool is represented by the ratio of the Gibbs free energy:

[0034]

[0035] The carbon content in the molten pool is calculated according to the material balance in the converter:

[0036]

[0037] In the formula, ω(C%) i is the content of carbon at T iCarbon content of molten steel at time T, M is total mass of the molten pool, Si i Mn i P i Fe i C i T i is the oxidation amount of each element at time T.

[0038] Further, the step S6 comprises: according to the characteristics of the specific converter, the carbon content in the molten pool is empirically corrected:

[0039]

[0040] In the formula, ρ O ρ N ρ co , are the mass percentages of oxygen, nitrogen, carbon monoxide and carbon dioxide in the corrected flue gas data, and T is the temperature of the molten steel in the converter.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] The present application indirectly measures the end-point carbon of the molten steel in the converter through big data analysis of the converter flue gas, which can replace manual carbon measurement, reduce labor intensity, reduce cost, improve labor productivity, and promote intelligent steelmaking. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flowchart of a method for indirectly measuring the carbon content of molten steel based on big data analysis of converter flue gas according to the present application;

[0044] Figure 2 is a comparison diagram of simulated measurement values and actual values according to the present application. DETAILED DESCRIPTION

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0046] Referring to the accompanying Figure 1 , the present application proposes a method for indirectly measuring the carbon content of molten steel based on big data analysis of converter flue gas, which specifically comprises the following steps:

[0047] S1, obtaining initial molten iron information;

[0048] The information related to the initial molten iron is obtained through the relevant production information system of the steel plant, including the initial molten iron composition, molten iron temperature, etc.

[0049] S2. Obtain converter flue gas composition information;

[0050] The flue gas composition online analysis system installed in the steelmaking converter obtains real-time converter flue gas composition information, mainly including nitrogen content, oxygen content, carbon dioxide content and carbon monoxide content, and this information is updated periodically.

[0051] S3, empirical correction of flue gas composition;

[0052] According to the specific characteristics of converter flue gas composition, empirical correction is made:

[0053]

[0054] Where x O 、x N 、x co 、 are the mass percentages of oxygen, nitrogen, carbon monoxide and carbon dioxide in the flue gas measurement data, respectively, and T is the temperature of molten steel in the converter.

[0055] S4. Calculation of oxidation amount of each element;

[0056] Due to the intake of air at the converter mouth and the secondary combustion in the flue, the flue gas composition detected by the gas analyzer is not equal to the initial flue gas composition of the initial molten pool reaction, and the flue gas composition needs to be corrected.

[0057] From the nitrogen balance in the flue gas, we can know that:

[0058] F N(i) +0.79·F 空气(i) =F 烟气(i) N% (i)

[0059] Where, F N(i) 、F 空气(i) 、F 烟气(i) 、N% (i) T i Nitrogen, furnace mouth air, furnace mouth flue gas, and nitrogen percentage content in flue gas at all times;

[0060] Get T i Furnace mouth air intake at all times:

[0061] F 空气(i) =(N% (i) ·F 烟气(i) -F N(i) ) / 0.79

[0062] If the inhaled air is completely combusted, the amount of oxygen for the secondary combustion is:

[0063] 0.21·F 空气(i)

[0064] According to the above, the flue gas amount of CO2 after the secondary combustion is:

[0065] CO2% (i) ·F 烟气(i) -0.21·F 空气(i)

[0066] The flue gas amount of CO is:

[0067] CO% (i) ·F 烟气(i) -2·0.21·F 空气(i)

[0068] In the formula, CO2% is the CO2 content in the flue gas at T time; CO% is the CO content in the flue gas at T time. (i) i (i) i

[0069] There are many factors affecting the secondary combustion, mainly including the design of the oxygen lance nozzle, the lance position, the oxygen supply system, the charging system and the furnace shape, etc.

[0070]

[0071] In the formula, F is the CO2 flow generated by the secondary combustion at T time; a and c are constants, a = 0.2 and c = 0.75. i

[0072] Therefore, the CO2 generated by the oxidation reaction between the oxygen supplied by the initial oxygen lance and the carbon elements in the molten pool is:

[0073]

[0074] The generated CO is:

[0075]

[0076] S5, calculation of carbon content in the molten pool;

[0077] The oxidation distribution ratio of each element in the molten pool is represented by the ratio of Gibbs free energy:

[0078]

[0079] The carbon content in the molten pool is calculated according to the material balance in the converter:

[0080] ​​​​​​

[0081] ω(C %) = 0.0004T + 0.0002M i T i Melt carbon content % at T i Si i Mn i P i Fe i C i Oxidation amount of each element at T

[0082] S6, empirical correction of carbon content in the melt pool;

[0083] According to the specific converter characteristics, the carbon content in the melt pool is empirically corrected:

[0084]

[0085] ρ O , ρ N , ρ co , are the mass percentages of oxygen, nitrogen, carbon monoxide and carbon dioxide in the corrected flue gas data, and T is the temperature of the molten steel in the converter.

[0086] The experimental converter of a certain steel grade (carbon content of 0.03%) flue gas composition data collected by the present application is measured offline, and the measurement results are compared with the actual values. The hit rate of the measurement results can reach 80% in the range of 0.025%-0.035% carbon content, and the offline simulation measurement results are compared with the actual values as shown in Figure 2 .

[0087] The present application calculates the carbon content of the molten steel in the converter according to the measured converter flue gas composition data, and further corrects the carbon content of the molten steel in the converter based on the converter flue gas big data analysis to improve the accuracy of the indirect measurement of the carbon content of the molten steel.

[0088] The present application does not exhaust the known technology.

[0089] The above-described embodiments are merely preferred embodiments of the present application and do not limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A method for indirectly measuring carbon content of molten steel based on converter flue gas big data analysis, characterized in that: The method comprises the following steps: S1, obtaining initial molten iron information; S2, obtaining converter flue gas composition information; S3, flue gas composition experience correction; S4, each element oxidation amount calculation; S5, molten pool carbon content calculation; S6, molten pool carbon content experience correction.

2. The method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis according to claim 1, characterized in that: In the step S1, the initial molten iron related information is obtained through a production information system related to a steelmaking plant, including initial molten iron composition and temperature.

3. The method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis according to claim 1, characterized in that: In the step S2, real-time converter flue gas composition information is obtained through a flue gas composition online analysis system installed on a steelmaking converter, including nitrogen content, oxygen content, carbon dioxide content and carbon monoxide content.

4. The method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis according to claim 3, characterized in that: The step S3 comprises: according to the flue gas composition characteristics related to a specific converter, experience correction is performed. wherein x O , x N , x co , are the mass percentages of oxygen, nitrogen, carbon monoxide and carbon dioxide, respectively, in the flue gas measurement data, and T is the temperature of the molten steel in the converter.

5. The method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis according to claim 4, characterized in that: The step S4 comprises: According to nitrogen balance in the flue gas: F N(i) +0.79 · F 空气(i) = F 烟气(i) · N% (i) In the formula, F N(i) , F 空气(i) , F 烟气(i) , N% (i) are the nitrogen content, the air content, the flue gas content, and the nitrogen content in the flue gas, respectively i at the time T i Instantaneous uptake at the mouth of the furnace: F 空气(i) = (N % 0.79) / 0.79 (i) • F 烟气(i) - F N(i) / 0.79 Supposing that the inhaled air is completely combusted, the oxygen amount for secondary combustion is: 0.21·F 空气(i) According to the above, the flue gas amount of CO2 after secondary combustion of the flue gas is: -0.21 · F (i) • F 烟气(i) -0.21 · F 空气(i) The flue gas amount of CO is: CO % (i) • F 烟气(i) -2 · 0.21 · F 空气(i) Where, CO2% (i) T i CO2 content in flue gas at any moment; CO% (i) T i CO content in flue gas at any moment (%); wherein T is T i CO2 flow generated by the secondary combustion at time t; a, c are constants, a = 0.2, c = 0.75; Therefore, the CO2 generated by the oxidation reaction between the oxygen supplied by the initial oxygen lance and the carbon element in the molten pool is: The generated CO is:

6. The method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis according to claim 5, characterized in that: The step S5 comprises: the oxidation distribution ratio of each element in the molten pool is represented by the ratio of Gibbs free energy: The molten pool carbon content is calculated according to the material balance in the converter: where ω (C %) i is T i at the time t i , M i , P i , Fe i , C i is the oxidation amount of each element at the time t i .

7. The method for indirectly measuring the carbon content of molten steel based on converter flue gas big data analysis according to claim 6, characterized in that: The step S6 comprises: according to the characteristics of a specific converter, experience correction is performed on the molten pool carbon content: wherein ρ O , ρ N , ρ co , are the corrected mass percentages of oxygen, nitrogen, carbon monoxide and carbon dioxide, respectively, in the flue gas, and T is the temperature of the molten steel in the converter.

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