Method for evaluating activity of hearth by using flow resistance index of slag and iron in hearth of hydrogen-rich blast furnace

Abstract

According to the method for evaluating the activity of the hearth through the slag iron flow resistance index of the hydrogen-rich blast furnace hearth, a slag iron flow resistance index model is constructed on the basis of the influence of the volume fraction of furnace bosh hydrogen on a slag iron retention model and a slag iron viscosity model, and therefore the activity of the hydrogen-rich blast furnace hearth is evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen enrichment in blast furnace ironmaking, and in particular to a method for evaluating the activity of a hydrogen-enriched blast furnace hearth by using the slag iron flow resistance index. Background Art

[0002] In order to address the carbon emission problem in the traditional blast furnace ironmaking process, hydrogen-rich blast furnace technology came into being. Hydrogen-rich blast furnace technology refers to a new blast furnace ironmaking process that reduces carbon emissions by introducing hydrogen-rich gas into the blast furnace to replace part of the traditional coke and using hydrogen to reduce the iron oxides in the iron ore. Due to the strong permeability of hydrogen, the metallization rate of the iron ore will increase, the ferrous oxide content in the primary slag will decrease, and the physical properties of the primary slag will change. However, the composition of the primary slag is significantly affected by the amount of hydrogen in the furnace bosh. Therefore, for hydrogen-rich blast furnaces that spray different amounts of hydrogen, the flow resistance of the slag in the dead material column will also change, which will not be able to reflect the working status of the furnace hearth in a timely and accurate manner, resulting in fluctuations in the furnace condition and causing serious safety and economic problems. In view of this, it is necessary to design a method for evaluating the activity of the furnace hearth based on the flow resistance index of the slag in the hydrogen-rich blast furnace hearth to solve the above problems. Summary of the Invention

[0003] The object of the present invention is to provide a method for evaluating the activity of a hydrogen-rich blast furnace hearth by using the slag iron flow resistance index.

[0004] To achieve the above object, the present invention provides a blast furnace condition control method based on hearth dead material column status judgment, comprising the following steps:

[0005] S1: adjust the hydrogen gas volume fraction in the blast furnace bosh to between 0-10%;

[0006] S2: Constructing slag iron flow resistance index model:

[0007]

[0008] Where μ is the slag viscosity, Pa·s;

[0009] ε is the void fraction of dead material column, dimensionless;

[0010] d is the particle equivalent diameter, m;

[0011] v is the fluid superficial velocity, m / s;

[0012] h s is the furnace slag iron retention rate;

[0013] S3: Constructing a calculation model for the furnace slag and iron retention rate:

[0014]

[0015] Where α is the viscosity correction coefficient, dimensionless;

[0016] β is the temperature correction coefficient, dimensionless,

[0017] C pm is the capillary number, dimensionless; its calculation formula is:

[0018] Where, ρ L is the density of blast furnace slag, kg / m 3 ;

[0019] g is the acceleration due to gravity, m / s 2 ; is the coke shape factor, dimensionless;

[0020] d p is the diameter of the coke in the furnace, m;

[0021] σ L is the surface tension of slag, N / m;

[0022] θ is the contact angle between slag and coke, °;

[0023] ε is the void fraction of the dead material column, dimensionless;

[0024] S4. Construct a calculation model for slag viscosity:

[0025] logη=-2.7+0.55F,

[0026] Where η is the slag viscosity, dPa·s;

[0027] F is a dimensionless variable; its calculation formula is:

[0028] Wherein, w(MO) is the mole fraction of each component, %;

[0029] C / S is the ratio of CaO / SiO2 mass fraction in the slag system, dimensionless;

[0030] S5. Substitute the production parameters of the target blast furnace and calculate its slag iron flow resistance index AHS. An AHS value within the range of 1-700 indicates good furnace hearth activity, while an AHS value outside the range indicates poor furnace hearth activity.

[0031] Furthermore, in the slag component w(MO), w(FeO)=30-3[%H].

[0032] This invention provides a method for evaluating the hearth activity of a hydrogen-rich blast furnace using the slag flow resistance index. Based on the influence of the bosh hydrogen gas volume fraction on the slag retention model and the slag viscosity model, a slag flow resistance index model is constructed to evaluate the hearth activity of the hydrogen-rich blast furnace. Based on the practical application of hydrogen-rich blast furnace smelting, this method comprehensively considers the influence of hydrogen volume on slag volume, slag composition, and viscosity. This method can accurately and timely reflect the hearth activity of the hydrogen-rich blast furnace, thus guiding actual blast furnace production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flowchart of a method for evaluating the activity of a hydrogen-rich blast furnace hearth using the slag iron flow resistance index in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following describes several preferred embodiments of the present invention with reference to the accompanying drawings to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0035] See also Figure 1 As shown, the present invention provides a method for evaluating the activity of a hydrogen-rich blast furnace hearth by using the slag iron flow resistance index, comprising the following steps:

[0036] S1. Constructing slag iron flow resistance index model: Where μ is the slag viscosity, Pa·s; ρ is the slag density, kg / m 3 ;ε dead material column porosity, dimensionless; Shape factor, generally taken as 0.89, dimensionless; d is the particle equivalent diameter, m; v is the fluid apparent velocity, generally taken as 0.125, m / s; h s is the furnace slag and iron retention rate.

[0037] S2. The slag flow resistance index model in step S1 is combined with the slag retention rate and slag viscosity under different bosh gas hydrogen volume fractions to obtain the change trend of the slag flow resistance index in actual blast furnace production to evaluate the hearth activity of different blast furnaces.

[0038] Furthermore, in step S2, the calculation model of the furnace slag iron retention rate is: Where α is the viscosity correction coefficient, dimensionless; β is the temperature correction coefficient, dimensionless; C pm is the capillary number, dimensionless; V H2 is the hydrogen volume fraction of the bosh gas, %.

[0039] The calculation formula of slag viscosity is: logη=-2.7+0.55F, where η is the slag viscosity, dPa·s; F is a variable, dimensionless.

[0040] Furthermore, the capillary number characterizes the actual slag-iron coke penetration process of the blast furnace, and its calculation formula is: Where, ρ L is the density of blast furnace slag, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ; is the coke shape factor, dimensionless; d p is the diameter of the coke in the furnace, m; σ L is the surface tension of the slag, N / m; θ is the contact angle between the slag and the coke, °; ε is the void fraction of the dead material column, dimensionless.

[0041] In the slag system, w(FeO)=30-3V H2 , V H2 is the hydrogen volume fraction of the bosh gas, %.

[0042] Among them, the diameter of the coke in the furnace is d p The method for determining the porosity of the dead material column is as follows: based on the blast furnace hearth damage investigation and the results of tuyere coke sampling, the relationship between the hearth coke diameter and the coke fed into the furnace, and the hearth coke diameter and the porosity of the dead material column is established to obtain the hearth coke diameter d p and the porosity of the dead material column.

[0043] An implementation case

[0044] This embodiment provides a method for evaluating the activity of a blast furnace hearth using the slag iron retention index, and combines the method with actual blast furnace production, including the following steps:

[0045] S1. Arrange the values required for calculating the blast furnace hearth slag iron resistance index, and collect the data parameters of different hydrogen injection volume fractions of a blast furnace as shown in Table 1;

[0046] Table 1 Actual production parameters of a blast furnace

[0047] Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Alkalinity 1.1 1.12 1.13 1.15 1.11 1.12 Magnesium-aluminum ratio 0.67 0.69 0.68 0.66 0.67 0.7 Coke particle size (mm) 40.25 42.61 41.96 41.53 42.76 40.01 Dead material column porosity 0.31 0.35 0.33 0.36 0.34 0.38 Bosh hydrogen gas volume fraction (%) 0 2 4 6 8 10

[0048] S2. Establish a calculation model for the furnace slag and iron retention rate: α is the viscosity correction coefficient, which is calculated based on the slag viscosity μ and the standard slag viscosity at 1500℃; β is the temperature correction coefficient, which is calculated based on the slag melting temperature and the molten iron temperature; V H2 is the hydrogen volume fraction of the bosh gas, %.

[0049] in,

[0050] S3. Establish a slag-iron viscosity model: logη=-2.7+0.55F, where η is the slag viscosity, dPa·s; F is a dimensionless variable.

[0051] in, w(MO) is the molar fraction of each component, %; C / S is the ratio of CaO / SiO2 mass fraction in the slag system, dimensionless.

[0052] In the slag system, w(FeO)=30-3V H2 , V H2 is the hydrogen volume fraction of the bosh gas, %.

[0053] S4. The production parameters of a blast furnace in step S1 are respectively introduced into the calculation model of furnace hearth slag iron retention, the calculation model of slag iron viscosity, and the slag iron flow resistance index model. The resulting structure is shown in the following table.

[0054] Table 2 Calculation results of slag iron retention rate, slag iron viscosity and slag iron flow resistance index in a blast furnace hearth

[0055] Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Slag iron flow resistance index 721.11 417.12 687.81 509.70 722.54 526.02 Slag and iron retention rate (%) 6.58 6.60 6.84 7.01 7.71 8.72 Slag iron viscosity (Pa·s) 0.182 0.212 0.250 0.276 0.295 0.312

[0056] It can be seen that this embodiment starts from the nature of slag penetration (porous medium model / slag flow resistance), uses mathematical theory to derive, introduces the influence of the bosh hydrogen gas volume fraction on the slag retention model and slag viscosity model, and evaluates the hearth activity from the perspective of slag flow resistance.

[0057] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for evaluating the activity of a hydrogen-rich blast furnace hearth using the slag iron flow resistance index, characterized in that: The following steps are involved: S1: adjust the hydrogen gas volume fraction in the blast furnace bosh to between 0-10%; S2: Constructing slag iron flow resistance index model: Where μ is the slag viscosity, Pa·s; ε is the void fraction of dead material column, dimensionless; d is the particle equivalent diameter, m; v is the fluid superficial velocity, m / s; h s is the furnace slag iron retention rate; S3: Constructing a calculation model for the furnace slag and iron retention rate: Where α is the viscosity correction coefficient, dimensionless; β is the temperature correction coefficient, dimensionless, C pm is the capillary number, dimensionless; The calculation formula is: Where, ρ L is the density of blast furnace slag, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ; is the coke shape factor, dimensionless; d p is the diameter of the coke in the furnace, m; σ L is the surface tension of slag, N / m; θ is the contact angle between slag and coke, °; ε is the void fraction of the dead material column, dimensionless; S4. Construct a calculation model for slag viscosity: logη=-2.7+0.55F, Where η is the slag viscosity, dPa·s; F is a variable, dimensionless; The calculation formula is: Wherein, w(MO) is the mole fraction of each component, %; C / S is the ratio of CaO / SiO2 mass fraction in the slag system, dimensionless; S5. Substitute the production parameters of the target blast furnace and calculate its slag iron flow resistance index AHS. An AHS value within the range of 1-700 indicates good furnace hearth activity, while an AHS value outside the range indicates poor furnace hearth activity.

2. The method for evaluating the activity of a hydrogen-rich blast furnace hearth by using the flow resistance index of slag iron in the hearth of a hydrogen-rich blast furnace according to claim 1, characterized in that: In the slag-based components w(MO), w(FeO)=30-3[%H].

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