Methods and systems for predicting molten iron temperature in the KR molten iron pretreatment process

Abstract

This invention discloses a method and system for predicting the temperature of molten iron in the KR (Korean Refined Metal) pretreatment process. The method includes: acquiring the current temperature, weight, physical dimensions of the ladle, and physical dimensions of the agitator in the KR agitated molten iron pretreatment process; obtaining a quantitative relationship between the agitator rotation speed and the characteristic variables of molten iron flow; acquiring the current arrangement of refractory materials in the ladle and the physical properties of the refractory materials' heat transfer properties; obtaining a relationship between the molten iron temperature drop rate and the change in the characteristic variables of molten iron flow; obtaining a relationship between the molten iron temperature and the agitation time; and calculating the temperature of the molten iron under target conditions and time. Using the technical solution of this invention, the temperature of molten iron in the KR agitated molten iron pretreatment process can be quantitatively predicted, providing a reference for reducing temperature drop and improving desulfurization efficiency.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking technology in the metallurgical industry, and particularly relates to a method and system for predicting the temperature of molten iron in the KR molten iron pretreatment process. Background Technology

[0002] In China, most steel mills employ KR (Knowledge, Refinement, and Harshness) stirring desulfurization in their hot metal pretreatment processes. This method uses mechanical rotation to enhance the reaction efficiency between the molten iron and the desulfurizing agent, achieving efficient removal of sulfur content. However, the vortex formed at the top of the ladle during KR stirring accelerates the rate of hot metal temperature increase, and simultaneously increases the heat transfer rate between the molten iron and the refractory material on the ladle wall. These factors lead to a decrease in hot metal temperature, which in turn slows down the desulfurization reaction. Furthermore, the lower temperature hinders the melting of the desulfurizing agent, disrupting the kinetics of the desulfurization reaction. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for predicting the temperature of molten iron in the KR molten iron pretreatment process, which can quantitatively predict the temperature of molten iron under target operating conditions and stirring time by obtaining the comprehensive influence of process parameters on molten iron flow and heat transfer.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for predicting the temperature of molten iron in a KR molten iron pretreatment process, comprising:

[0006] Step S1: Obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions.

[0007] Step S2: Based on the current KR stirring molten iron pretreatment process parameters such as molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions, establish a three-dimensional flow model of molten iron during the KR stirring process;

[0008] Step S3: Obtain molten iron flow data based on the three-dimensional flow model of molten iron during the KR stirring process;

[0009] Step S4: Based on the flow data, obtain the quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow;

[0010] Step S5: Obtain the current refractory material arrangement method and refractory material heat transfer physical property parameters for the molten iron ladle masonry.

[0011] Step S6: Based on the arrangement of refractory materials in the front ladle and the physical properties of refractory heat transfer, establish a heat transfer model of molten iron during the KR stirring process;

[0012] Step S7: Obtain the molten iron temperature distribution data based on the KR stirring process molten iron heat transfer model;

[0013] Step S8: Based on the molten iron temperature distribution data, obtain the relationship between the molten iron temperature drop rate and the changes in the molten iron flow characteristic variables;

[0014] Step S9: Based on the quantitative influence of the stirring paddle speed on the characteristic variables of molten iron flow and the relationship between the molten iron temperature drop rate and the change of the characteristic variables of molten iron flow, the relationship between the molten iron temperature and the stirring time is determined.

[0015] Step S10: Obtain the temperature of molten iron under the target working conditions and time by using the formula for the change of molten iron temperature with stirring time.

[0016] As a preferred embodiment, the quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow is as follows:

[0017] ε=C1·n 3

[0018] Where ε is the turbulent kinetic energy dissipation rate; n is the rotational speed; and C1 is a constant.

[0019] As a preferred embodiment, the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow is as follows:

[0020] k Tem =C2+C3·ε

[0021] Where, k Tem ε is the rate of temperature drop of molten iron; ε is the rate of turbulent kinetic energy dissipation; C2 and C3 are constants.

[0022] As a preferred option, the relationship between molten iron temperature and stirring time is as follows:

[0023] T = T0 - (C2 + C1C3n) 3 )t

[0024] Where T0 is the initial temperature of the molten iron; n is the rotational speed; and t is the stirring time.

[0025] This invention also provides a system for predicting the temperature of molten iron in the KR molten iron pretreatment process, comprising:

[0026] The first processing module is used to obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions.

[0027] The second processing module is used to establish a three-dimensional flow model of molten iron in the KR stirring process based on the molten iron temperature, weight, physical dimensions of the ladle, and physical dimensions of the stirring paddle in the current KR stirring molten iron pretreatment process.

[0028] The third processing module is used to obtain molten iron flow data based on the three-dimensional flow model of molten iron during the KR stirring process.

[0029] The fourth processing module is used to obtain a quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow based on the flow data.

[0030] The fifth processing module is used to obtain the current refractory material arrangement method and refractory heat transfer physical property parameters of the molten iron ladle;

[0031] The sixth processing module is used to establish a heat transfer model of molten iron during the KR stirring process based on the arrangement of refractory materials in the front ladle and the physical properties of refractory heat transfer.

[0032] The seventh processing module is used to obtain molten iron temperature distribution data based on the KR stirring process molten iron heat transfer model;

[0033] The eighth processing module is used to obtain the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow based on the molten iron temperature distribution data;

[0034] The ninth processing module is used to determine the relationship between the temperature of molten iron and the stirring time based on the quantitative influence relationship between the stirring paddle speed and the characteristic variables of molten iron flow and the relationship between the temperature drop rate of molten iron and the characteristic variables of molten iron flow.

[0035] The tenth processing module is used to obtain the temperature of molten iron under the target working conditions and time by using the relationship between molten iron temperature and stirring time.

[0036] As a preferred embodiment, the quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow is as follows:

[0037] ε=C1·n 3

[0038] Where ε is the turbulent kinetic energy dissipation rate; n is the rotational speed; and C1 is a constant.

[0039] As a preferred embodiment, the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow is as follows:

[0040] k Tem =C2+C3·ε

[0041] Where, k Tem ε is the rate of temperature drop of molten iron; ε is the rate of turbulent kinetic energy dissipation; C2 and C3 are constants.

[0042] As a preferred option, the relationship between molten iron temperature and stirring time is as follows:

[0043] T = T0 - (C2 + C1C3n) 3 )t

[0044] Where T0 is the initial temperature of the molten iron; n is the rotational speed; and t is the stirring time.

[0045] This invention obtains parameters such as molten iron temperature, weight, ladle physical dimensions, and agitator physical dimensions during the current KR stirred molten iron pretreatment process. Based on these parameters, a three-dimensional mathematical model of molten iron flow during the KR stirred process is established. The three-dimensional flow data is processed and analyzed to obtain a quantitative relationship between the agitator rotation speed and the characteristic variables of molten iron flow. The arrangement of refractory materials in the current ladle and the physical properties of refractory material heat transfer are also obtained. Based on these parameters, a mathematical model of molten iron heat transfer during the KR stirred process is established to calculate the molten iron temperature distribution. The molten iron temperature distribution data is processed to obtain a relationship between the molten iron temperature drop rate and the change in characteristic variables of molten iron flow. Through these relationships, a relationship between molten iron temperature and stirring time is obtained, and the temperature of the molten iron under target conditions and time is calculated. This invention can quantitatively predict the molten iron temperature during the KR stirred molten iron pretreatment process, providing a reference for reducing temperature drop and improving desulfurization efficiency. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0047] Figure 1 This is a flowchart of the method for predicting the temperature of molten iron in the KR molten iron pretreatment process according to an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram illustrating the variation of molten iron flow characteristic variables with stirring paddle speed in an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the refractory material arrangement for the molten iron ladle in an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of the iron temperature distribution in an embodiment of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] Example 1:

[0054] like Figure 1 As shown, this embodiment of the invention provides a method for predicting the temperature of molten iron in the KR molten iron pretreatment process, including:

[0055] Step S1: Obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions.

[0056] Step S2: Obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, ladle physical dimensions, and stirring paddle physical dimensions, and establish a three-dimensional physical model of KR stirring based on the physical dimensions parameters;

[0057] Step S3: Set the fluid computation domain according to the KR stirring three-dimensional physical model, and use the molten iron-air multiphase VOF model and the molten iron flow k-ε model to numerically calculate the molten iron flow data;

[0058] Step S4: Based on the flow data, obtain the quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow;

[0059] Step S5: Obtain the current refractory material arrangement method and refractory material heat transfer physical property parameters for the molten iron ladle masonry.

[0060] Step S6: Based on the current refractory material arrangement method for molten iron ladle construction, the refractory material heat transfer physical property parameters, and the KR stirring three-dimensional physical model, set the calculation domain for refractory material and molten iron heat transfer during the KR stirring process, and establish the KR stirring process molten iron heat transfer model.

[0061] Step S7: Based on the KR stirring process molten iron heat transfer model, the temperature distribution of refractory and molten iron is numerically calculated; further, the molten iron temperature distribution under different stirring paddle speeds is calculated to obtain molten iron temperature distribution data under different stirring paddle speed conditions.

[0062] Step S8: Based on the molten iron temperature distribution data, obtain the relationship between the molten iron temperature drop rate and the changes in the molten iron flow characteristic variables;

[0063] Step S9: Based on the quantitative influence of the stirring paddle speed on the characteristic variables of molten iron flow and the relationship between the molten iron temperature drop rate and the change of the characteristic variables of molten iron flow, the relationship between the molten iron temperature and the stirring time is determined.

[0064] Step S10: Obtain the initial temperature of the molten iron and the speed of the stirring paddle in the current KR molten iron pretreatment process, substitute them into the formula for the change of molten iron temperature with stirring time, and calculate the result of the change of molten iron temperature with time; based on the target stirring time of the current molten iron pretreatment, determine the temperature of the molten iron at the target time.

[0065] As one embodiment of the present invention, the quantitative influence of the stirring paddle speed on the characteristic variables of molten iron flow is expressed as follows:

[0066] ε=C1·n 3

[0067] Where ε is the turbulent kinetic energy dissipation rate; n is the rotational speed; and C1 is a constant.

[0068] As one embodiment of the present invention, the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow is as follows:

[0069] k Tem =C2+C3·ε

[0070] Where, k Tem ε is the rate of temperature drop of molten iron; ε is the rate of turbulent kinetic energy dissipation; C2 and C3 are constants.

[0071] As one embodiment of the present invention, the relationship between molten iron temperature and stirring time is as follows:

[0072] T = T0 - (C2 + C1C3n) 3 )t

[0073] Where T0 is the initial temperature of the molten iron; n is the rotational speed; and t is the stirring time.

[0074] This embodiment uses an initial molten iron temperature of 1630K, a weight of 250 tons, and top and bottom diameters of 4066mm and 3738mm respectively. The stirring paddle has a cross-shaped blade with a height of 950mm and a thickness of 480mm, a rotation radius of 700mm, and an immersion depth of 1500mm. Based on these parameters, a three-dimensional mathematical model of molten iron flow during the KR stirring process is established to calculate the molten iron velocity, the molten iron-air interface distribution, and the rotation of the stirring paddle. Figure 2 The constant C1 in the quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow is 9.01 × 10⁻⁶. -7 .like Figure 3 As shown, the current arrangement of refractory materials in the molten iron ladle and the physical properties of refractory heat transfer are further obtained. The refractory materials include aluminosilicate bricks 2, clay bricks 2, composite insulation boards 3, aluminosilicate castables 4, and a steel shell 5. Specific physical properties are shown in Table 1. Based on the above parameters, a mathematical model of molten iron heat transfer during the KR stirring process is established, including mutual heat transfer between the steel shell and refractory materials, between refractory materials and molten iron, and between molten iron and air. The temperature distribution of the molten iron is calculated, as shown below. Figure 4As shown. By processing the molten iron temperature distribution data, the constants C2 and C3 in the relationship between the molten iron temperature drop rate and the change of molten iron flow characteristic variables were determined to be 0.2236 and 1.4116, respectively. Based on the above relationship, the relationship between molten iron temperature and stirring time was determined, and the calculated temperature of molten iron after stirring for 10 minutes at the target operating condition of 90 rpm was found to be 1618.5 K.

[0075] Table 1

[0076]

[0077] This embodiment calculates the comprehensive impact of parameters such as molten iron temperature, weight, ladle physical dimensions, agitator physical dimensions, ladle refractory material arrangement, and refractory material heat transfer properties on the molten iron temperature change during the KR molten iron pretreatment process. Based on the judgment criteria of this invention, the molten iron temperature during the KR agitated molten iron pretreatment process can be quantitatively predicted, providing a reference for reducing temperature drop and improving desulfurization efficiency.

[0078] Example 2:

[0079] This invention also provides a system for predicting the temperature of molten iron in the KR molten iron pretreatment process, comprising:

[0080] The first processing module is used to obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions.

[0081] The second processing module is used to establish a three-dimensional flow model of molten iron in the KR stirring process based on the molten iron temperature, weight, physical dimensions of the ladle, and physical dimensions of the stirring paddle in the current KR stirring molten iron pretreatment process.

[0082] The third processing module is used to obtain molten iron flow data based on the three-dimensional flow model of molten iron during the KR stirring process.

[0083] The fourth processing module is used to obtain a quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow based on the flow data.

[0084] The fifth processing module is used to obtain the current refractory material arrangement method and refractory heat transfer physical property parameters of the molten iron ladle;

[0085] The sixth processing module is used to establish a heat transfer model of molten iron during the KR stirring process based on the arrangement of refractory materials in the front ladle and the physical properties of refractory heat transfer.

[0086] The seventh processing module is used to obtain molten iron temperature distribution data based on the KR stirring process molten iron heat transfer model;

[0087] The eighth processing module is used to obtain the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow based on the molten iron temperature distribution data;

[0088] The ninth processing module is used to determine the relationship between the temperature of molten iron and the stirring time based on the quantitative influence relationship between the stirring paddle speed and the characteristic variables of molten iron flow and the relationship between the temperature drop rate of molten iron and the characteristic variables of molten iron flow.

[0089] The tenth processing module is used to obtain the temperature of molten iron under the target working conditions and time by using the relationship between molten iron temperature and stirring time.

[0090] As one embodiment of the present invention, the quantitative influence of the stirring paddle speed on the characteristic variables of molten iron flow is expressed as follows:

[0091] ε=C1·n 3

[0092] Where ε is the turbulent kinetic energy dissipation rate; n is the rotational speed; and C1 is a constant.

[0093] As one embodiment of the present invention, the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow is as follows:

[0094] k Tem =C2+C3·ε

[0095] Where, k Tem ε is the rate of temperature drop of molten iron; ε is the rate of turbulent kinetic energy dissipation; C2 and C3 are constants.

[0096] As one embodiment of the present invention, the relationship between molten iron temperature and stirring time is as follows:

[0097] T = T0 - (C2 + C1C3n) 3 )t

[0098] Where T0 is the initial temperature of the molten iron; n is the rotational speed; and t is the stirring time.

[0099] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for predicting the temperature of molten iron in a KR molten iron pretreatment process, characterized in that, include: Step S1: Obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions. Step S2: Based on the current KR stirring molten iron pretreatment process parameters such as molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions, establish a three-dimensional flow model of molten iron during the KR stirring process; Step S3: Obtain molten iron flow data based on the three-dimensional flow model of molten iron during the KR stirring process; Step S4: Based on the flow data, obtain the quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow; Step S5: Obtain the current refractory material arrangement method and refractory material heat transfer physical property parameters for the molten iron ladle masonry. Step S6: Based on the arrangement of refractory materials in the front ladle and the physical properties of refractory heat transfer, establish a heat transfer model of molten iron during the KR stirring process; Step S7: Obtain the molten iron temperature distribution data based on the KR stirring process molten iron heat transfer model; Step S8: Based on the molten iron temperature distribution data, obtain the relationship between the molten iron temperature drop rate and the changes in the molten iron flow characteristic variables; Step S9: Based on the quantitative influence of the stirring paddle speed on the characteristic variables of molten iron flow and the relationship between the molten iron temperature drop rate and the change of the characteristic variables of molten iron flow, the relationship between the molten iron temperature and the stirring time is determined. Step S10: Obtain the temperature of molten iron under the target working conditions and time by using the formula for the change of molten iron temperature with stirring time.

2. The method for predicting the temperature of molten iron in the KR molten iron pretreatment process as described in claim 1, characterized in that, The quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow is as follows: ε=C1·n 3 Where ε is the turbulent kinetic energy dissipation rate; n is the rotational speed; and C1 is a constant.

3. The method for predicting the temperature of molten iron in the KR molten iron pretreatment process as described in claim 2, characterized in that, The relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow is as follows: k Tem =C2+C3 ε Where, k Tem ε is the rate of temperature drop of molten iron; ε is the rate of turbulent kinetic energy dissipation; C2 and C3 are constants.

4. The method for predicting the temperature of molten iron in the KR molten iron pretreatment process as described in claim 3, characterized in that, The relationship between molten iron temperature and stirring time is as follows: T=T0-(C2+C1C3n 3 )t Where T0 is the initial temperature of the molten iron; n is the rotational speed; and t is the stirring time.

5. A system for predicting the temperature of molten iron in the KR molten iron pretreatment process, characterized in that, include: The first processing module is used to obtain the current KR stirring molten iron pretreatment process parameters, including molten iron temperature, weight, molten iron ladle physical dimensions, and stirring paddle physical dimensions. The second processing module is used to establish a three-dimensional flow model of molten iron in the KR stirring process based on the molten iron temperature, weight, physical dimensions of the ladle, and physical dimensions of the stirring paddle in the current KR stirring molten iron pretreatment process. The third processing module is used to obtain molten iron flow data based on the three-dimensional flow model of molten iron during the KR stirring process. The fourth processing module is used to obtain a quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow based on the flow data. The fifth processing module is used to obtain the current refractory material arrangement method and refractory heat transfer physical property parameters of the molten iron ladle; The sixth processing module is used to establish a heat transfer model of molten iron during the KR stirring process based on the arrangement of refractory materials in the front ladle and the physical properties of refractory heat transfer. The seventh processing module is used to obtain molten iron temperature distribution data based on the KR stirring process molten iron heat transfer model; The eighth processing module is used to obtain the relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow based on the molten iron temperature distribution data; The ninth processing module is used to determine the relationship between the temperature of molten iron and the stirring time based on the quantitative influence relationship between the stirring paddle speed and the characteristic variables of molten iron flow and the relationship between the temperature drop rate of molten iron and the characteristic variables of molten iron flow. The tenth processing module is used to obtain the temperature of molten iron under the target working conditions and time by using the relationship between molten iron temperature and stirring time.

6. The hot metal temperature prediction system for the KR hot metal pretreatment process as described in claim 5, characterized in that, The quantitative relationship between the stirring paddle speed and the characteristic variables of molten iron flow is as follows: ε=C1·n 3 Where ε is the turbulent kinetic energy dissipation rate; n is the rotational speed; and C1 is a constant.

7. The hot metal temperature prediction system for the KR hot metal pretreatment process as described in claim 6, characterized in that, The relationship between the rate of temperature drop of molten iron and the change of characteristic variables of molten iron flow is as follows: k Tem =C2+C3 ε Where, k Tem ε is the rate of temperature drop of molten iron; ε is the rate of turbulent kinetic energy dissipation; C2 and C3 are constants.

8. The hot metal temperature prediction system for the KR hot metal pretreatment process as described in claim 7, characterized in that, The relationship between molten iron temperature and stirring time is as follows: T=T0-(C2+C1C3n 3 )t Where T0 is the initial temperature of the molten iron; n is the rotational speed; and t is the stirring time.

Images