Method and system for predicting end point sulfur content of kr hot metal pretreatment

Abstract

The application discloses a KR molten iron pretreatment endpoint sulfur content prediction method and system, comprising the following steps: obtaining the current KR molten iron pretreatment process molten iron ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle rotating speed and immersion depth parameters; obtaining the molten iron flow field change relationship formula according to the above obtained parameters; obtaining the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters; obtaining the desulfurization rate constant and mass transfer coefficient change relationship formula according to the above parameters and the molten iron flow field distribution data; determining the molten iron sulfur content change relationship formula with the KR molten iron pretreatment process parameters according to the desulfurization mass transfer coefficient, and determining the target time molten iron sulfur content. The technical scheme of the application can quantitatively predict the molten iron sulfur content change and the target time sulfur content size under different KR molten iron pretreatment process parameters.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steelmaking in the metallurgical industry, and particularly relates to a KR molten iron pretreatment endpoint sulfur content prediction method and system. BACKGROUND

[0002] Sulfur is a harmful element in most steel grades. With the increase of sulfur content, the mechanical processing performance, corrosion resistance, and magnetic performance of steel will be significantly deteriorated. With the development of social economy, the requirements for steel performance are becoming more and more demanding, and the control of sulfur content in steel is also put forward with higher requirements. From the aspects of process efficiency and operation cost, molten iron pretreatment desulfurization is the most economical and efficient desulfurization method. Among many molten iron pretreatment desulfurization methods, KR mechanical stirring method has obvious advantages in desulfurization effect, desulfurization cycle, and slagging iron loss due to its superior kinetic conditions, and has become the mainstream development direction of molten iron pretreatment desulfurization. With the continuous growth of production capacity, each steel enterprise puts forward higher requirements for production efficiency and production cost, and the current requirements for molten iron pretreatment desulfurization are not only the control of the extremely low value of sulfur in molten iron, but also pay more attention to the technical and economic indexes such as desulfurizer utilization rate and desulfurization cycle which have significant influence on the whole process. How to accurately predict the change of molten iron sulfur content in KR desulfurization process, and then determine the desulfurization cycle, further improve the desulfurization efficiency, reduce the desulfurizer consumption and shorten the production cycle is the problem that needs to be solved urgently. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a KR molten iron pretreatment endpoint sulfur content prediction method and system, which can quantitatively predict the molten iron sulfur content at the target time by obtaining the relationship between the molten iron sulfur content and the stirring paddle speed, the molten iron weight, the desulfurizer weight, and the desulfurizer diameter.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0005] A KR molten iron pretreatment endpoint sulfur content prediction method, comprising:

[0006] Step S1, obtaining the current KR molten iron pretreatment process molten iron ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters;

[0007] Step S2, determining the molten iron flow field change relationship according to the current KR molten iron pretreatment process molten iron ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters;

[0008] Step S3, obtaining the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters;

[0009] Step S4, according to the KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters, determine the desulfurization rate constant and the variation formula of mass transfer coefficient;

[0010] Step S5, determine the variation formula of molten iron sulfur content with KR molten iron pretreatment process parameters, according to the variation formula to determine the target time of molten iron sulfur content.

[0011] As preferred, in step S2, according to the obtained ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters, the molten iron flow field variation formula is determined by multiphase flow numerical simulation calculation.

[0012] As preferred, in step S3, according to the obtained desulfurizer addition amount and desulfurizer diameter parameters and molten iron flow field variation formula, the desulfurization rate constant and the variation formula of mass transfer coefficient are determined by desulfurization numerical simulation calculation.

[0013] As preferred, in step S4, the variation formula of molten iron sulfur content with KR molten iron pretreatment process parameters is determined as follows:

[0014]

[0015] Wherein, C4 is a constant; t is the reaction time; [%S] and [%S]0 are the sulfur mass percentage content at the current time and the initial time, respectively; W de And W m The total mass of desulfurizer particles and the mass of molten iron, respectively; n is the stirring paddle speed; d p The diameter of the desulfurizer.

[0016] The present application also provides a KR molten iron pretreatment endpoint sulfur content prediction system, comprising:

[0017] Step S1, obtaining the current KR molten iron pretreatment process ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters;

[0018] Step S2, according to the current KR molten iron pretreatment process ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters, determine the molten iron flow field variation formula;

[0019] Step S3, obtaining the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters;

[0020] Step S4, according to the KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters, determine the desulfurization rate constant and the variation formula of mass transfer coefficient;

[0021] Step S5, determining the change relationship of the molten iron sulfur content with the KR molten iron pretreatment process parameters, and determining the molten iron sulfur content at the target moment according to the change relationship.

[0022] As preferred, the second processing module determines the change relationship of the molten iron flow field according to the obtained structure parameters of the ladle and the stirring paddle, the weight and temperature parameters of the molten iron, and the stirring paddle rotating speed and immersion depth parameters, through multiphase flow numerical simulation calculation.

[0023] As preferred, the third processing module determines the change relationship of the desulfurization rate constant and the mass transfer coefficient according to the obtained desulfurizer addition amount and desulfurizer diameter parameters and the change relationship of the molten iron flow field, through desulfurization numerical simulation calculation.

[0024] As preferred, the fourth processing module is used to determine the change relationship of the molten iron sulfur content with the KR molten iron pretreatment process parameters as follows:

[0025]

[0026] Wherein, C4 is a constant; t is the reaction time; [%S] and [%S]0 are the sulfur mass percentage content at the current moment and the initial moment, respectively; W de and W m are the total mass of the desulfurizer particles and the mass of the molten iron, respectively; n is the stirring paddle rotating speed; d p is the desulfurizer diameter.

[0027] The present application obtains the structure parameters of the ladle and the stirring paddle, the weight and temperature parameters of the molten iron, and the rotating speed and immersion depth parameters of the stirring paddle in the current KR molten iron pretreatment process; calculates the change relationship of the molten iron flow field according to the above obtained parameters; obtains the desulfurizer addition amount and the desulfurizer diameter parameters in the current KR molten iron pretreatment process; calculates the change relationship of the desulfurization rate constant and the mass transfer coefficient according to the above parameters and the molten iron flow field distribution data; determines the change relationship of the molten iron sulfur content with the KR molten iron pretreatment process parameters according to the desulfurization mass transfer coefficient, and determines the molten iron sulfur content at the target moment. The present application can quantitatively predict the change of the molten iron sulfur content under different KR molten iron pretreatment process parameters and the size of the sulfur content at the target moment. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0029] Figure 1This is a flowchart of the method for predicting the sulfur content at the end point of KR molten iron pretreatment according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram illustrating the variation of the turbulent kinetic energy dissipation rate of molten iron with the stirring paddle rotation speed in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram illustrating the variation of the desulfurization rate constant with the stirring paddle speed, the amount of desulfurizer added, and the diameter of the desulfurizer in an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram illustrating the change in sulfur content in molten iron in this embodiment. Detailed Implementation

[0033] 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.

[0034] 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.

[0035] Example 1:

[0036] like Figure 1 As shown, this embodiment of the invention provides a method for predicting the sulfur content at the end of KR molten iron pretreatment, including:

[0037] Step S1: Obtain the structural parameters of the ladle and stirring paddle, the weight and temperature parameters of the molten iron, and the stirring paddle speed and immersion depth parameters of the current KR molten iron pretreatment process;

[0038] Step S2: Determine the relationship between the changes in the molten iron flow field based on the structural parameters of the ladle and stirring paddle in the current KR molten iron pretreatment process, the weight and temperature parameters of the molten iron, and the stirring paddle speed and immersion depth parameters.

[0039] Step S3: Obtain the current amount of desulfurizing agent added and the diameter parameters of the desulfurizing agent in the KR molten iron pretreatment process;

[0040] Step S4: Based on the current amount of desulfurizing agent added and the diameter parameters of the desulfurizing agent in the KR molten iron pretreatment process, determine the relationship between the desulfurization rate constant and the mass transfer coefficient.

[0041] Step S5, determining the change relation of the molten iron sulfur content with the KR molten iron pretreatment process parameters, bringing the target desulfurization time into the change relation of the molten iron sulfur content with the KR molten iron pretreatment process parameters, and calculating the molten iron sulfur content at the target time.

[0042] As an embodiment of the present application, in step S2, a stirring process physical model is established by a three-dimensional modeling software according to the obtained molten iron ladle and stirring paddle structure parameters. The molten iron weight and temperature parameters, and the stirring paddle rotating speed and immersion depth parameters are input as initial conditions, and the size distribution of the turbulent energy of the molten iron at different rotating speeds is calculated by the molten air VOF multiphase flow model and k-ε flow model. The change relation of the molten iron flow field is determined according to the size distribution of the turbulent energy of the molten iron at different rotating speeds, that is,

[0043] ε=C1·n 3

[0044] wherein C1 is a constant; ε is the turbulent energy dissipation rate, m 2 / s 3 ; n is the rotating speed, rpm.

[0045] As an embodiment of the present application, in step S3, a molten iron sulfur content concentration UDS and desulfurizer desulfurization DPM numerical model is established according to the molten iron turbulent energy distribution, the obtained desulfurizer addition amount and desulfurizer diameter parameters are input as input parameters, the size distribution of the desulfurization rate constant and the mass transfer coefficient under different conditions are calculated, and the change relation of the desulfurization rate constant and the mass transfer coefficient is determined, that is,

[0046]

[0047]

[0048] wherein C2 and C3 are constants; β is the desulfurization rate constant, s -1 ; k s is the desulfurization mass transfer coefficient, m / s; n is the stirring paddle rotating speed, rpm; d p is the desulfurizer diameter, mm; m de is the desulfurizer addition amount, kg / ton of molten iron; ρ p and ρ are the densities of the desulfurizer and the molten iron, kg / m 3 .

[0049] As an embodiment of the present application, in step S4, the change relation of the molten iron sulfur content with the KR molten iron pretreatment process parameters is determined as follows:

[0050]

[0051] Where C4 is a constant; t is the reaction time; [%S] and [%S]0 are the sulfur mass percentages at the current time and the initial time, respectively; W de and W m These represent the total mass of the desulfurizing agent particles and the mass of the molten iron, respectively; n is the stirring paddle speed; d p The diameter of the desulfurizing agent.

[0052] In this embodiment, the total height of the molten iron ladle is 3986 mm, and the top and bottom diameters are 4066 mm and 3738 mm, respectively. The weight of the molten iron is 250 t, and the temperature is 1630 K. The stirring paddle is cross-shaped, with a rotation radius of 700 mm, a height of 950 mm, and a thickness of 480 mm. The stirring paddle rotates at 90 rpm, and the immersion depth is 1600 mm. The physical properties of the molten iron and air phase are shown in Table 1. Figure 2 As shown, through multiphase flow numerical simulation calculations under different stirring impeller rotations, the value of C1 in the equation for the variation of the molten iron flow field was determined to be 8.0 × 10⁻⁶. -7 The total mass of desulfurizing agent added was 1378 kg, and the diameter of the desulfurizing agent was 0.62 mm. For example... Figure 3 As shown, through numerical simulation calculations of desulfurization under different rotation speeds, total added desulfurizer mass, and desulfurizer diameters, the C2 value in the desulfurization rate constant variation formula was determined to be 8.67 × 10⁻⁶. -6 In the formula for the change of mass transfer coefficient, C3 is 1.45 × 10⁻⁶. -3 Based on the relationship between the sulfur content of molten iron and the KR molten iron pretreatment process parameters, C4 in the relationship is determined to be -1.45 × 10⁻⁶. -3 Based on the relationship between the sulfur content of molten iron and the KR molten iron pretreatment process parameters, the following equation is obtained: Figure 4 The graph showing the change in sulfur content in molten iron indicates that the sulfur content in molten iron at the target time of 600s is 13ppm.

[0053] Table 1

[0054]

[0055] This embodiment calculates the comprehensive influence of ladle and agitator structural parameters, molten iron weight and temperature parameters, and agitator rotation speed and immersion depth on the multiphase flow of molten iron during the KR molten iron pretreatment process. It quantitatively determines the impact of parameters such as agitator rotation speed, molten iron weight, desulfurizer weight, and desulfurizer diameter on the sulfur content changes in molten iron during the KR molten iron pretreatment process. Based on the determination criteria of this invention, the sulfur content of molten iron can be predicted specifically according to actual production conditions, thereby improving desulfurization efficiency, reducing desulfurizer consumption, and shortening the production cycle.

[0056] Example 2:

[0057] The embodiment of the present application also provides a KR molten iron pretreatment endpoint sulfur content prediction system, comprising:

[0058] Step S1, obtaining the current KR molten iron pretreatment process molten iron ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle rotating speed and immersion depth parameters;

[0059] Step S2, determining the molten iron flow field change relationship according to the current KR molten iron pretreatment process molten iron ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle rotating speed and immersion depth parameters;

[0060] Step S3, obtaining the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters;

[0061] Step S4, determining the desulfurization rate constant and mass transfer coefficient change relationship according to the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters;

[0062] Step S5, determining the molten iron sulfur content change relationship with the KR molten iron pretreatment process parameters, and determining the molten iron sulfur content at the target moment according to the change relationship.

[0063] As an embodiment of the present application, the second processing module determines the molten iron flow field change relationship through multiphase flow numerical simulation calculation according to the obtained molten iron ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle rotating speed and immersion depth parameters.

[0064] As an embodiment of the present application, the third processing module determines the desulfurization rate constant and mass transfer coefficient change relationship through desulfurization numerical simulation calculation according to the obtained desulfurizer addition amount and desulfurizer diameter parameters and the molten iron flow field change relationship.

[0065] As an embodiment of the present application, the fourth processing module is used for determining the molten iron sulfur content change relationship with the KR molten iron pretreatment process parameters as follows:

[0066]

[0067] Wherein, C4 is a constant; t is the reaction time; [%S] and [%S]0 are the sulfur mass percentage content at the current moment and the initial moment, respectively; W de and W m are the total mass of the desulfurizer particles and the mass of the molten iron, respectively; n is the stirring paddle rotating speed; d p is the desulfurizer diameter.

[0068] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application 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 of predicting the end point sulfur content of a KR hot metal pretreatment, characterized by, Comprising: Step S1, obtaining the current KR molten iron pretreatment process ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters; Step S2, determining the molten iron flow field change relationship according to the current KR molten iron pretreatment process ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters; Step S3, obtaining the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters; Step S4, determining the change relationship of desulfurization rate constant and mass transfer coefficient according to the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters; Step S5, determining the change relationship of molten iron sulfur content with KR molten iron pretreatment process parameters, and determining the molten iron sulfur content at the target time according to the change relationship; In step S2, a stirring process physical model is established through a three-dimensional modeling software according to the obtained ladle and stirring paddle structure parameters; the molten iron weight and temperature parameters, and the stirring paddle speed and immersion depth parameters are input as initial conditions, and the size distribution of the turbulent kinetic energy of molten iron under different speeds is calculated through the molten iron-air VOF multiphase flow model and k-ε flow model; the change relationship of the molten iron flow field is determined through the size distribution of the turbulent kinetic energy of molten iron under different speeds, that is, ； wherein, C 1 is a constant; is the rate of turbulent energy dissipation; n is the impeller speed; In step S4, the molten iron sulfur content concentration UDS and desulfurizer desulfurization DPM numerical model are established according to the turbulent kinetic energy distribution of molten iron, the obtained desulfurizer addition amount and desulfurizer diameter parameters are input as parameters, and the size distribution of the desulfurization rate constant and mass transfer coefficient under different conditions is calculated to determine the change relationship of the desulfurization rate constant and mass transfer coefficient, that is, ； wherein, C 2 and C 3 are constants; β is the desulfurization rate constant; k s is the desulfurization mass transfer coefficient; d p is the desulfurizer diameter; m de is the desulfurizer addition amount; ρ p and ρ are the desulfurizer and molten iron densities, respectively; In step S5, the change relationship of the molten iron sulfur content with the KR molten iron pretreatment process parameters is determined as follows: ； wherein, C 4 is a constant; t is the reaction time; [%S] and [%S]0are the current and initial sulfur mass percentage, respectively; W de and W m is the total mass of desulfurizer particles and the mass of molten iron, respectively.

2. A KR molten iron pretreatment end point sulfur content prediction system for realizing the KR molten iron pretreatment end point sulfur content prediction method of claim 1, characterized by, Comprising: Step S1, obtaining the current KR molten iron pretreatment process ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters; Step S2, determining the molten iron flow field change relationship according to the current KR molten iron pretreatment process ladle and stirring paddle structure parameters, molten iron weight and temperature parameters, and stirring paddle speed and immersion depth parameters; Step S3, obtaining the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters; Step S4, determining the change relationship of desulfurization rate constant and mass transfer coefficient according to the current KR molten iron pretreatment process desulfurizer addition amount and desulfurizer diameter parameters; Step S5, determining the change relationship of molten iron sulfur content with KR molten iron pretreatment process parameters, and determining the molten iron sulfur content at the target time according to the change relationship.

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