Converter blowing numerical simulation quantitative evaluation method

Abstract

The invention belongs to the technical field of steel smelting, and particularly relates to a converter blowing numerical simulation quantitative evaluation method. Comprising the following steps that (1) a multiphase flow model VOF of a molten steel phase and an oxygen phase in a converter is established, the molten steel phase is a multi-component model and comprises molten steel components and carbon components, the oxygen phase comprises oxygen components, the initial content of the carbon components is set, the oxygen components are dynamically added in a molten steel phase impact pit area, and the molten steel phase impact pit area is obtained; simulating the consumption process of the carbon component based on a preset carbon-oxygen reaction kinetic equation; and (2) quantitatively evaluating the advantages and disadvantages of the blowing process by comparing the consumption speeds of the carbon components under different process conditions. According to the method, the converter blowing process can be efficiently and accurately improved, key indexes such as carbon and oxygen deposits can be reduced, a large amount of research and development and production test cost can be saved, and the improved process can create huge economic benefits for enterprises.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel smelting, and particularly relates to a numerical simulation quantitative evaluation method for converter blowing. Background Art

[0002] Currently, in the research on analyzing or optimizing the converter blowing process by numerical simulation methods, there is a lack of a direct and accurate evaluation method. At present, the mixing speed of molten steel is usually characterized by the proportion of low molten steel flow velocity and the diffusion rate of tracers to evaluate the quality of the molten pool flow field. However, these evaluation methods have obvious defects and cannot accurately evaluate the quality of the converter blowing process.

[0003] For example, different thresholds selected by the low flow velocity proportion method will result in different results. Different process schemes will obtain different flow velocity values and different flow field distributions. This will lead to the same proportion of low flow velocity, but the actual mixing speed may be different. For the tracer diffusion method, different addition positions will result in different results. For an asymmetric flow field, it will further affect the initial tracer flow direction and cause inaccurate mixing time. Summary of the Invention

[0004] The purpose of the present invention is to provide a numerical simulation quantitative evaluation method for converter blowing to solve the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] A numerical simulation quantitative evaluation method for converter blowing includes the following steps:

[0007] (1) Establish a multiphase flow model VOF of the molten steel phase and gas phase in the converter. The molten steel phase is a multi-component model, including molten steel components and carbon components. The gas phase includes top-blown O2 components and bottom-blown gas components. Set the initial content of the carbon component. The oxygen component enters from the impact pit area of the molten steel phase, and based on a preset carbon-oxygen reaction equation, simulate the consumption process of the carbon component;

[0008] (2) Quantitatively evaluate the quality of the blowing process by comparing the consumption rates of the carbon component under different process conditions.

[0009] Further, the carbon-oxygen reaction equation in step (1) is implemented by any one of the direct reaction method between multiphase flows, the method of adding reaction components, and the method of assigning reaction components.

[0010] Further, the physical property parameters of the carbon component and oxygen component do not need to be consistent with the actual physical properties of carbon and oxygen elements. In order to accelerate the simulation calculation process, the consumption ratio of the carbon component can be increased in the carbon-oxygen reaction.

[0011] Furthermore, the direct interfacial reaction method for multiphase flow is as follows: The reaction interface between the molten steel phase and the oxygen phase is calculated using the VOF multiphase flow model. Based on the defined interfacial reaction rate, a chemical reaction occurs at the phase interface between the molten steel phase and the oxygen phase. The injection of the oxygen phase is achieved through the model inlet boundary conditions according to the process conditions.

[0012] Furthermore, the method of adding reactive components is as follows: In the VOF multiphase flow model, the multicomponent model of the molten steel phase also includes an oxygen component. The carbon-oxygen reaction equation is realized by injecting the oxygen component in the impact pit area of the molten steel phase using the discrete phase model. After the oxygen component enters the molten steel phase, the carbon component in the molten steel phase is consumed through chemical reactions between components. The injection amount of the oxygen component is determined according to the process conditions.

[0013] Furthermore, the method of assigning reactive components is as follows: In the VOF multiphase flow model, the multicomponent model of the molten steel phase also includes an oxygen component. The oxygen component concentration is directly assigned in a certain area of the impact pit in the molten steel phase, and the oxygen component supply is maintained through periodic update commands. The carbon component in the molten steel phase is consumed through chemical reactions between components. The range and concentration of the oxygen component assignment area are determined according to the process conditions.

[0014] Furthermore, the comparison method for the consumption rate of the carbon component in step (2) is to compare the carbon content under different processes at the same reaction time or to compare the time required for different processes to reach the same carbon content.

[0015] The present invention has the following beneficial effects:

[0016] The converter combined blowing digital model of the present invention can more accurately analyze and evaluate different converter blowing processes, and can more intuitively obtain the limiting links and improvement directions of a process, which is an essential theoretical basis for improving the converter blowing process. By applying this evaluation method and model, the converter blowing process can be improved efficiently and accurately, key indicators such as the carbon-oxygen product can be reduced, and a large amount of R & D and production test costs can be saved. The improved process can create huge economic benefits for enterprises. The present invention can cover the entire process. The three methods are respectively adapted to high-precision simulation (interfacial reaction), medium-speed optimization (DPM injection), and rapid pre-screening (assignment method); the quantitative evaluation based on real converter parameters (such as bottom blowing layout and gas volume) can directly guide production. The error of the three methods is within the range of ±5%, and the model has high reliability. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the converter carbon-oxygen reaction simulation for the single-ring 8-hole scheme in Embodiment 1 of the present invention.

[0018] Figure 2 It is a schematic diagram of the converter carbon-oxygen reaction simulation for the double-ring 16-hole scheme in Embodiment 1 of the present invention.

[0019] Figure 3It is the carbon content distribution diagram of the cross-section at the center of the molten pool at a certain moment in the single-ring 8-hole scheme of Embodiment 1 of the present invention.

[0020] Figure 4 It is the carbon content distribution diagram of the cross-section at the center of the molten pool at a certain moment in the double-ring 16-hole scheme of Embodiment 1 of the present invention.

[0021] Figure 5 It is the comparison diagram of the carbon content change curves of the single-ring 8-hole scheme and the double-ring 16-hole scheme in Embodiment 1 of the present invention.

[0022] Figure 6 It is the comparison diagram of the carbon content at 28s of the single-ring 8-hole scheme and the double-ring 16-hole scheme in Embodiment 1 of the present invention. Specific implementation mode

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the following further details the present invention in conjunction with specific embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Embodiment 1:

[0025] This embodiment provides a numerical simulation quantitative evaluation method for converter blowing, in which the carbon-oxygen reaction equation is realized by the direct reaction method between phases of multiphase flow.

[0026] Taking the optimization research of the blowing process of a 300t converter as an example, the bottom blowing schemes of single-ring 8 holes and double-ring 16 holes are compared. The top blowing processes of the two schemes are the same, and the total bottom blowing gas volume is the same, both 800 Nm 3 / h. The three-dimensional converter model (diameter 6m, molten pool depth 1.8m), and the bottom blowing holes are arranged at the bottom of the furnace;

[0027] Technical scenario:

[0028] Single-ring 8-hole scheme: 8 holes are evenly distributed on the circumference with a radius of 1.4m; double-ring 16-hole scheme: 8 holes in each of the inner and outer rings (inner ring radius 1.5m, outer ring radius 1.7m). Multiphase flow (VOF) model: includes molten steel phase and gas phase, and the interphase chemical reaction module is turned on. Component model: the component transfer module is turned on.

[0029] Material setting: The molten steel phase includes hot metal components and carbon components, and the gas phase includes O2 components and Ar components (bottom blowing gas components). The gas phase density is the ideal gas model. Boundary condition setting: The top blowing and bottom blowing gases are injected through velocity inlets. The bottom blowing is the Ar single-hole flow rate of 100 Nm 3 / h, and the top blowing is the O2 flow rate of 65000 Nm 3 / h.

[0030] Result analysis:

[0031] As Figure 1-2 shown, the red area is the molten steel carbon-containing area, the blue area is the area where the carbon in the molten steel has been consumed by reaction, and the top-blowing gas trace line.

[0032] As Figure 3-4 shown, different colors represent different carbon contents, and the carbon content distribution in the molten steel bath at a certain interface at this moment can be intuitively seen from the color scale on the left side of the figure.

[0033] As Figure 5 shown, comparison of the carbon content change curves: the double-ring 16-hole bottom-blowing scheme consumes the carbon component faster than the single-ring bottom-blowing scheme.

[0034] As Figure 6 shown, at 28 s, the carbon content of the double-ring 16-hole bottom-blowing scheme is 0.025%, and the carbon content of the single-ring bottom-blowing scheme is 0.075%.

[0035] Optimization conclusion: The double-ring 16-hole bottom-blowing scheme is significantly better than the single-ring bottom-blowing scheme, can achieve a faster carbon-oxygen reaction rate, has a lower carbon residue in the same time, and can reach a lower carbon-oxygen product.

[0036] Example 2:

[0037] This example provides a numerical simulation quantitative evaluation method for converter blowing, in which the carbon-oxygen reaction equation is realized by adding reaction components.

[0038] Technical scenario:

[0039] Compare the single-ring 8-hole and double-ring 16-hole bottom-blowing schemes (total gas volume 800 Nm 3 / h). Three-dimensional converter model (diameter 6 m, molten bath depth 1.8 m), bottom-blowing holes are arranged at the bottom of the furnace; single-ring scheme: 8 holes are evenly distributed on the circumference with a radius of 1.4 m; double-ring 16-hole scheme: 8 holes in each of the inner and outer rings (inner ring radius 1.5 m, outer ring radius 1.7 m). Multiphase flow (VOF) model: includes molten steel phase and gas phase, and the interphase mass transfer module is turned on. Component model: turn on the component transfer module and the volume reaction module. Discrete phase model (DPM): set an injection source at the impact pit position and inject the oxygen component of the molten steel phase.

[0040] Material setting: The molten steel phase includes hot metal components, carbon components and oxygen components, and the gas phase includes O2 components and Ar components (bottom-blowing gas components). The gas phase density is the ideal gas model.

[0041] Boundary condition setting: The top-blowing and bottom-blowing gases are injected through a velocity inlet. The bottom-blowing is Ar single-hole flow rate 100 Nm 3 / h, and the top-blowing is O2 flow rate 65000 Nm 3 / h.

[0042] Result analysis: Comparison of carbon content changes: The carbon component in the 16-hole bottom blowing scheme reacts and consumes faster than that in the 8-hole bottom blowing scheme. At the 28th second, the carbon content in the 16-hole bottom blowing scheme is 0.026%, and the carbon content in the 8-hole bottom blowing scheme is 0.077%.

[0043] Optimization conclusion: The 16-hole bottom blowing scheme is significantly better than the 8-hole bottom blowing scheme, with lower carbon residue in the same time and a lower carbon-oxygen product that can be achieved.

[0044] Example 3:

[0045] This example provides a numerical simulation and quantitative evaluation method for converter blowing, in which the carbon-oxygen reaction equation is realized by the assignment reaction component method.

[0046] Technical scenario:

[0047] Compare the single-ring 8-hole and double-ring 16-hole bottom blowing schemes (total gas volume 800 Nm 3 / h). Three-dimensional converter model (diameter 6 m, bath depth 1.8 m), and the bottom blowing holes are arranged at the bottom of the furnace; single-ring scheme: 8 holes are evenly distributed on the circumference with a radius of 1.4 m; double-ring 16-hole scheme: 8 holes in each of the inner and outer rings (inner ring radius 1.5 m, outer ring radius 1.7 m). Multiphase flow (VOF) model: includes molten steel phase and gas phase. Component model: The component transfer module and volume reaction module are turned on. Unit marking: The thickness of the impact pit position is 0.06 m, and the radius is 1 m area. Calculation command: frequency 0.001 s, oxygen component concentration in the marked area is 0.2.

[0048] Material setting: The molten steel phase includes hot metal components, carbon components and oxygen components, and the gas phase includes O2 components and Ar components (bottom blowing gas components). The gas phase density is the ideal gas model.

[0049] Boundary condition setting: The top blowing and bottom blowing gases are injected through velocity inlets. The bottom blowing is Ar single-hole flow rate 100 Nm 3 / h, and the top blowing is O2 flow rate 65000 Nm3 / h.

[0050] Result analysis: Comparison of carbon content changes: The carbon component in the 16-hole bottom blowing scheme reacts and consumes faster than that in the 8-hole bottom blowing scheme. At the 28th second, the carbon content in the 16-hole bottom blowing scheme is 0.024%, and the carbon content in the 8-hole bottom blowing scheme is 0.072%.

[0051] Optimization conclusion: The 16-hole bottom blowing scheme is significantly better than the 8-hole bottom blowing scheme, with lower carbon residue in the same time and a lower carbon-oxygen product that can be achieved.

[0052] The above embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention.

[0053] The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A numerical simulation quantitative evaluation method for converter blowing, characterized in that, The method includes the following steps: (1) Establish a VOF multiphase flow model for the molten steel phase and the gas phase in the converter. The molten steel phase is a multi-component model, including molten steel components and carbon components. The gas phase includes top-blown O2 components and bottom-blown gas components. Set the initial content of the carbon component. The oxygen component enters from the impact pit area of the molten steel phase, and the consumption process of the carbon component is simulated based on a preset carbon-oxygen reaction equation. (2) Quantitatively evaluate the advantages and disadvantages of the blowing process by comparing the consumption rates of the carbon component under different process conditions.

2. The numerical simulation quantitative evaluation method for converter blowing according to claim 1, wherein The carbon-oxygen reaction equation in step (1) is implemented by any one of the direct reaction method between multiphase flows, the method of adding reaction components, and the method of assigning reaction components.

3. The numerical simulation quantitative evaluation method for converter blowing according to claim 2, characterized in that The physical property parameters of the carbon component and the oxygen component do not need to be consistent with the actual physical properties of carbon and oxygen elements. To accelerate the simulation calculation process, the consumption ratio of the carbon component can be increased in the carbon-oxygen reaction.

4. The numerical simulation quantitative evaluation method for converter blowing according to claim 3, wherein The direct reaction method between multiphase flows is as follows: The reaction interface between the molten steel phase and the oxygen phase is calculated by using the VOF multiphase flow model. Based on the defined interfacial reaction rate, a chemical reaction occurs at the phase interface between the molten steel phase and the oxygen phase. The injection of the oxygen phase is realized through the model inlet boundary condition according to the process conditions.

5. The numerical simulation quantitative evaluation method for converter blowing according to claim 3, characterized in that, The method of adding reaction components is as follows: In the VOF multiphase flow model, the multi-component model of the molten steel phase also includes the oxygen component. The carbon-oxygen reaction equation is realized by injecting the oxygen component into the impact pit area of the molten steel phase in a discrete phase model. After the oxygen component enters the molten steel phase, the carbon component in the molten steel phase is consumed through chemical reactions between components. The injection amount of the oxygen component is determined according to the process conditions.

6. The numerical simulation quantitative evaluation method for converter blowing according to claim 3, wherein The method of assigning reaction components is as follows: In the VOF multiphase flow model, the multi-component model of the molten steel phase also includes the oxygen component. The oxygen component concentration is directly assigned in a certain area of the impact pit of the molten steel phase, and the oxygen supply is maintained through a periodic update command. The carbon component in the molten steel phase is consumed through chemical reactions between components. The range and concentration of the oxygen component assignment area are determined according to the process conditions.

7. The numerical simulation quantitative evaluation method for converter blowing according to claim 3, characterized in that The method for comparing the consumption rate of the carbon component in step (2) is to compare the carbon content under different processes at the same reaction time or to compare the time required for different processes to reach the same carbon content.

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