KR molten iron desulphurization method

Abstract

The present application relates to a kind of KR molten iron desulfurization method, belong to molten iron desulfurization field, comprising the following steps: S1: automatically collecting molten iron quantity, molten iron sulfur content and optimizing relevant parameters, set target sulfur content after desulfurization;S2: KR desulfurization paddle insertion depth is optimized control;S3: the rotational speed of stirring paddle is optimized control;S4: desulfurizer addition speed is optimized control;S5: desulfurizer addition amount is optimized control;S6: stirring time is optimized control;S7: the optimized control parameters of step S2-S7 are output, and desulfurization treatment is controlled.

Description

Technical Field

[0001] This invention belongs to the field of molten iron desulfurization and relates to a KR molten iron desulfurization method. Background Technology

[0002] The insertion depth of the KR desulfurization agitator, the stirring speed, and the desulfurizing agent addition rate all affect the desulfurization effect in molten iron pretreatment. The utilization rate and the amount of desulfurizing agent added affect the desulfurization hit rate. The agitator insertion depth generally increases with the amount of molten iron, the stirring speed generally increases as the agitator diameter decreases due to wear and tear, the desulfurizing agent addition rate is generally kept constant at a suitable value, and the desulfurizing agent addition rate generally increases proportionally with the amount of molten iron and its sulfur content. However, the agitator insertion depth and stirring speed do not change proportionally, nor does the desulfurizing agent addition rate. Therefore, parameter adjustments in actual operation are often inaccurate and out of sync with actual desulfurization requirements, resulting in low desulfurizing agent utilization, high desulfurizing agent consumption, low desulfurization hit rate, and long desulfurization cycles. Summary of the Invention

[0003] In view of this, the purpose of this invention is to use an optimized hot metal pretreatment desulfurization model to optimize the insertion depth of the KR desulfurization agitator, agitation speed, desulfurizer addition speed, and desulfurizer addition amount. The changes in desulfurizer addition amount and sulfur consumption of desulfurizer are expressed by curves or functions. Through model control, the accuracy of KR desulfurization parameter control is improved, the operation of KR desulfurization parameter control is simplified, the utilization rate of desulfurizer is increased, the consumption of desulfurizer is reduced, the desulfurization hit rate is increased, and the desulfurization time is shortened.

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

[0005] A method for desulfurizing KR molten iron includes the following steps:

[0006] S1: Automatically collects molten iron quantity, molten iron sulfur content, and optimizes relevant parameters, and sets the target sulfur content after desulfurization;

[0007] S2: Optimize and control the insertion depth of the KR desulfurization impeller;

[0008] S3: Optimize and control the speed of the agitator;

[0009] S4: Optimize and control the rate of desulfurizer addition;

[0010] S5: Optimize and control the amount of desulfurizing agent added;

[0011] S6: Optimize and control the stirring time;

[0012] S7: Output the optimized control parameters of steps S2 to S7 to control the desulfurization process.

[0013] Furthermore, the optimization of the KR desulfurization impeller insertion depth described in step S2 specifically includes:

[0014] Obtain the impeller height and impeller diameter, and calculate:

[0015] Impeller insertion depth = Impeller height + (0.8~1.0) * Impeller diameter

[0016] When the clear space of the molten iron ladle is between 500mm and 700mm, take the upper limit; when the clear space of the molten iron ladle is greater than 700mm, take the lower limit.

[0017] Furthermore, the optimization of the stirring paddle speed described in step S3 specifically includes:

[0018] Obtain the starting motor current of the agitator and calculate:

[0019] Normal stirring speed current = (0.6~0.7) * stirring motor starting current

[0020] The normal current at which the agitator rotates was used as the adjustment standard to optimize the agitator rotation speed.

[0021] Furthermore, the optimization of the desulfurizing agent addition rate described in step S4 specifically includes controlling the desulfurizing agent addition rate to be between 1.0 kg / min·ton iron and 1.5 kg / min·ton iron.

[0022] Furthermore, the optimization of the desulfurizing agent dosage in step S5 specifically includes: expressing the sulfur consumption of the desulfurizing agent and the sulfur content of the molten iron using a curve or function:

[0023] Y = 0.05X -2 / 5

[0024] Where Y represents the sulfur consumption of the desulfurizing agent, that is, the amount of desulfurizing agent consumed to reduce the sulfur content of each ton of molten iron by 0.001%; ​​X represents the sulfur content of the molten iron.

[0025] Furthermore, the optimization of the stirring time described in step S6 specifically includes: increasing the stirring speed to 75 r / min to 105 r / min when the desulfurizing agent is first added, and maintaining the stirring speed at 75 r / min to 105 r / min after the desulfurizing agent is added, controlling the pure stirring time to 7 to 11 minutes. The stirring speed is related to the service life of the stirring paddle. When the stirring paddle is in its initial stage of use and has a short service life, such as after 50 uses (desulfurizing 50 ladles of molten iron), the stirring speed should be increased to 75 r / min or higher from the start of adding the desulfurizing agent, and maintained at 75 r / min after the desulfurizing agent is added. As the service life of the stirring paddle increases, such as after 100 uses, the stirring speed should be increased to 85 r / min or higher from the start of adding the desulfurizing agent, and maintained at 85 r / min after the desulfurizing agent is added. When the agitator reaches the end of its service life, such as 400 cycles, the agitation speed should be increased to 100 to 105 r / min from the start of adding the desulfurizer, and then maintained at 100 to 105 r / min after the desulfurizer is finished.

[0026] The beneficial effects of this invention are as follows: the desulfurization model automatically collects the original data for desulfurization calculation, runs the calculation according to the set conditions and program, outputs the desulfurization control parameters, and accurately controls the desulfurization process, thereby improving the utilization rate of desulfurizing agent, reducing the consumption of desulfurizing agent, increasing the desulfurization hit rate, and shortening the desulfurization time.

[0027] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0029] Figure 1 This is a flowchart of a KR molten iron desulfurization method;

[0030] Figure 2 The relationship between sulfur content in molten iron and sulfur consumption of desulfurizing agent. Detailed Implementation

[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0033] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0034] Please see Figures 1-2 This invention provides a KR molten iron desulfurization method. This method uses a desulfurization model to automatically collect the molten iron quantity and sulfur content. Based on the molten iron quantity, sulfur content, and target sulfur content after desulfurization, the desulfurization model calculates the agitator insertion depth, agitator rotation speed, desulfurizing agent dosage, and matches the desulfurizing agent addition speed and stirring time, outputting desulfurization parameters to precisely control the desulfurization process, thereby improving desulfurizing agent utilization, reducing desulfurizing agent consumption, increasing desulfurization hit rate, and shortening desulfurization processing time. The desulfurization model calculates the desulfurizing agent dosage based on the blast furnace molten iron sulfur content. When there is a deviation between the sulfur content of the KR molten iron entering the desulfurization station and the blast furnace molten iron sulfur content, the desulfurization model recalculates the desulfurizing agent dosage after receiving the KR molten iron entering the desulfurization station sulfur content and reminds the user to add more desulfurizing agent. This method includes the following steps:

[0035] The insertion depth of the agitator was optimized. The insertion depth refers to the distance from the bottom surface of the agitator to the surface of the molten iron, and is related to the agitator height and diameter. After analysis and comparison of results, the agitator insertion depth = agitator height + (0.8~1.0) * agitator diameter. For molten iron ladles with small clearance (500mm~700mm), the upper limit was used; for molten iron ladles with large clearance (greater than 700mm), the lower limit was used.

[0036] The stirring paddle speed is optimized. The stirring paddle speed is a measure of the amount of kinetic energy provided by the stirring paddle. The motor current during stirring is used as the adjustment standard. The normal stirring paddle speed current = (0.6~0.7) * stirring paddle starting motor current.

[0037] The desulfurizing agent addition rate needs to be optimized. If the addition rate is too high, the desulfurizing agent utilization rate will decrease; if the addition rate is too low, the desulfurization treatment time will be prolonged. The desulfurizing agent addition rate should be controlled between 1.0 kg / min / ton of iron and 1.5 kg / min / ton of iron.

[0038] The desulfurizing agent dosage was optimized. The dosage is related to the amount of molten iron, its sulfur content, and the target sulfur content after desulfurization, but it is not proportional to the sulfur content of the molten iron or the target sulfur content after desulfurization. Figure 2 As shown, the sulfur consumption of the desulfurizing agent and the sulfur content of the molten iron are represented by a curve or function: Y = 0.05X -2 / 5 . Figure 2 The horizontal axis represents the sulfur content of molten iron (%), and the vertical axis represents the sulfur consumption of the desulfurizing agent (kg / t). The sulfur consumption of the desulfurizing agent refers to the amount of desulfurization agent required to reduce the sulfur content of molten iron by 0.001%.

[0039] Optimization of stirring time: When adding desulfurizing agent, increase the stirring speed to high speed. After adding the desulfurizing agent, continue stirring at high speed, maintaining a pure stirring time of 7 to 11 minutes. Different values ​​correspond to different stirring paddle ages, generally increasing with the paddle's age. In the initial stage of use, when the paddle is young (e.g., after 50 uses, desulfurizing 50 ladles of molten iron), increase the stirring speed to 75 r / min or higher from the start of adding the desulfurizing agent, and maintain 75 r / min afterward. As the paddle age increases, such as after 100 uses, increase the stirring speed to 85 r / min or higher from the start of adding the desulfurizing agent, and maintain 85 r / min afterward. When the paddle reaches the end of its service life (e.g., after 400 uses), increase the stirring speed to 100 to 105 r / min from the start of adding the desulfurizing agent, and maintain 100 to 105 r / min afterward.

[0040] After adopting this desulfurization model, the model automatically collects the raw data for desulfurization calculation, runs calculations according to the set conditions and program, outputs desulfurization control parameters, and precisely controls the desulfurization process to improve the utilization rate of desulfurizing agent, reduce the consumption of desulfurizing agent, increase the desulfurization hit rate, and shorten the desulfurization time.

[0041] In the experiment, the sulfur consumption of the desulfurizing agent reached 0.209 kg / ton of molten iron, a decrease of 6.7%, the desulfurization hit rate reached 93.83%, an increase of 13.55%, and the desulfurization treatment time was shortened by 3.5 minutes.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for desulfurizing KR molten iron, characterized in that: Includes the following steps: S1: Automatically collects molten iron quantity, molten iron sulfur content, and optimizes relevant parameters, and sets the target sulfur content after desulfurization; S2: Optimize and control the insertion depth of the KR desulfurization impeller; S3: Optimize and control the speed of the agitator; S4: Optimize and control the rate of desulfurizer addition; S5: Optimize and control the amount of desulfurizing agent added; S6: Optimize and control the stirring time; S7: Output the optimized control parameters of steps S2 to S7 to control the desulfurization process; Step S2, which optimizes the insertion depth of the KR desulfurization impeller, specifically includes: Obtain the impeller height and impeller diameter, and calculate: Stirring blade insertion depth = stirring blade height + (0.8~1.0) * stirring blade diameter When the clear space of the molten iron ladle is between 500mm and 700mm, take the upper limit; when the clear space of the molten iron ladle is greater than 700mm, take the lower limit. Step S3, which involves optimizing the stirring paddle speed, specifically includes: Obtain the starting motor current of the agitator and calculate: Normal stirring speed current = (0.6~0.7) * stirring motor starting current The normal current at which the agitator rotates was used as the adjustment standard to optimize the agitator speed. Step S4, which optimizes the desulfurizing agent addition rate, specifically includes controlling the desulfurizing agent addition rate to 1.0 kg / min·ton iron to 1.5 kg / min·ton iron. Step S5, which optimizes the amount of desulfurizing agent added, specifically includes: expressing the sulfur consumption of the desulfurizing agent and the sulfur content of the molten iron using a curve or function: Y=0.05X -2 / 5 Where Y represents the sulfur consumption of the desulfurizing agent, that is, the amount of desulfurizing agent consumed to reduce the sulfur content of each ton of molten iron by 0.001%; ​​X represents the sulfur content of the molten iron. Step S6, which optimizes the stirring time, specifically includes: increasing the stirring speed to 75 r / min to 105 r / min when the desulfurizing agent is added, and continuing to stir at 75 r / min to 105 r / min after the desulfurizing agent is added, so as to control the pure stirring time to 7 to 11 minutes.

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