Ladle bottom blowing system based on a laval tube structure

Abstract

The utility model discloses a steel ladle bottom blowing system based on laval pipe structure belongs to metallurgical steelmaking technical field, specifically is between the gas supply pipe of steel ladle and gas source device adds laval pipe gas supply mechanism connection. Laval pipe gas supply mechanism includes gas delivery pipeline, laval pipe and gas source connecting pipe. Among them, gas delivery pipeline gas outlet end and the air inlet end coaxial communication of gas supply pipe. Coaxial on the end face of gas delivery pipeline air inlet end has round hole, and coaxially inserts gas source connecting pipe. The air inlet end of gas source connecting pipe is connected with gas source. Laval pipe air inlet end coaxial connection gas source connecting pipe gas outlet end. Further, the gas in the gas source can form a stable gas flow field at the air outlet end of the gas supply pipe through the laval pipe. The utility model fundamentally innovates the key link of steel ladle bottom blowing in steel smelting process, and provides the leading solution for realizing efficient and high-quality steel production.

Description

Technical Field

[0002] This utility model focuses on the field of metallurgical steelmaking technology and relates to a ladle bottom blowing system based on a Laval tube structure. It fundamentally innovates the key link of ladle bottom blowing in the steelmaking process and provides a cutting-edge solution for achieving efficient and high-quality steel production. Background Technology

[0004] In the complex process of modern steel smelting, bottom blowing technology undoubtedly occupies a pivotal position and is a core supporting element for improving steel quality and optimizing the overall smelting process.

[0005] like Figure 1 As shown, a traditional ladle bottom blowing system includes a gas supply system consisting of a gas source device and a gas supply pipe, and permeable bricks installed at the bottom of the ladle. The gas supply pipe is connected to the permeable bricks at its outlet, and inert gas (argon / nitrogen) is supplied from the gas source device into the ladle through the gas supply pipes and permeable bricks.

[0006] However, traditional ladle bottom blowing systems have revealed a series of deep-seated problems that urgently need to be solved in long-term practical applications:

[0007] From the perspective of gas distribution, the gas distribution in traditional systems exhibits obvious non-uniformity. This directly leads to the molten steel not being able to fully contact the gas during the reaction process, which seriously affects the uniformity and purity of the steel composition. Consequently, it has a negative impact on the quality of the final steel, making it difficult for the steel to meet the stringent requirements of high-end application fields in terms of key indicators such as performance stability and strength.

[0008] Traditional bottom-blown structures have inherent deficiencies in structural stability and durability, leading to frequent malfunctions. This not only significantly increases equipment maintenance costs, including manpower, resources, and repair materials, but also results in significantly longer downtime during production, severely restricting the production efficiency of steel companies, increasing operating costs, and weakening their competitiveness in the market.

[0009] Furthermore, in actual operation, accurately controlling key parameters such as the flow rate and pressure of the bottom-blown gas presents significant challenges. Due to the lack of effective control methods and precise monitoring equipment, traditional systems struggle to meet the stringent standards of modern steel production for high-quality molten steel and cannot adapt to the steel industry's trend towards high-end and refined production.

[0010] Of particular concern is the frequent occurrence of molten steel backflow, which often leads to blockage of the bottom-blowing permeable bricks in the ladle. This not only significantly reduces the bottom-blowing permeability rate, greatly diminishing the effectiveness of bottom blowing, but also forces operators to frequently manually reheat the permeable bricks to maintain permeability. This process not only consumes a large amount of manpower and time but also accelerates the wear and tear of the ladle permeable bricks, further increasing the company's production costs.

[0011] With the continued rapid development of the steel industry, market demands for steel quality and production efficiency are increasing. Against this backdrop, developing a new type of bottom-blowing ladle system with a Laval tube structure has become an urgent need for the industry. This has immeasurable practical significance for solving the long-standing problems plaguing steel enterprises and comprehensively improving the overall efficiency of steel smelting. Utility Model Content

[0013] To address the aforementioned problems, this invention proposes a bottom-blowing system for steel ladles based on a Laval tube structure. It aims to comprehensively and systematically overcome a series of persistent issues inherent in traditional bottom-blowing systems, such as uneven gas distribution, poor structural stability, and inaccurate parameter control. In particular, it provides an innovative solution to the industry-recognized pain point of molten steel backflow clogging the permeable bricks, thereby significantly improving steel quality, greatly increasing production efficiency, effectively reducing production costs, and helping steel enterprises achieve high-quality and sustainable development.

[0014] This utility model relates to a bottom-blowing system for a steel ladle based on a Laval tube structure. It is constructed by adding a Laval tube gas supply mechanism between the gas supply pipe and the gas source device of the steel ladle. The Laval tube gas supply mechanism includes a gas conveying pipe and a connecting pipe between the Laval tube and the gas source.

[0015] In this design, the outlet end of the gas delivery pipeline is coaxially connected to the inlet end of the gas supply pipe. A circular hole is coaxially opened on the end face of the inlet end of the gas delivery pipeline, through which a gas source connection pipe is coaxially inserted. The inlet end of the gas source connection pipe is connected to a gas source device. The inlet end of the Laval pipe is coaxially connected to the outlet end of the gas source connection pipe. Thus, the gas in the gas source can form a stable gas flow field at the outlet end of the gas supply pipe by passing through the Laval pipe. This invention fundamentally revolutionizes the key process of bottom blowing in steel smelting, providing a cutting-edge solution for achieving efficient and high-quality steel production.

[0016] The advantages of this utility model are:

[0017] 1. This utility model, based on a Laval tube structure, provides a bottom-blowing system for steel ladles. This system allows gas to pass evenly through the permeable bricks into the molten steel, promoting full contact and reaction between the molten steel and the gas, and significantly improving the uniformity and purity of the molten steel composition. This improvement in steel quality lays a solid foundation for producing high-quality steel, resulting in significant improvements in key performance indicators such as strength, toughness, and corrosion resistance, thus meeting the stringent requirements of high-end manufacturing industries.

[0018] 2. The bottom-blowing system of the ladle based on the Laval tube structure of this utility model greatly reduces the frequency of manual brick firing and maintenance to once every 100 heats, and the air permeability of the permeable bricks is always kept stable at over 99%. This significant improvement not only greatly reduces the frequency of manual firing of permeable bricks, reducing labor costs and labor intensity, but also significantly reduces the loss cost of permeable bricks in the ladle.

[0019] 3. This utility model, based on a Laval tube structure, successfully solves the industry problem of molten steel backflow clogging the permeable bricks, significantly improving the bottom-blowing permeability of the ladle. The reduced frequency of manual firing of permeable bricks and the lower cost of ladle permeable brick waste directly bring significant economic benefits to steel smelting enterprises. Simultaneously, the stable bottom-blowing effect also improves steel quality and production efficiency, enhancing the enterprise's competitiveness in the market. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a traditional ladle bottom blowing system;

[0022] Figure 2 This is a schematic diagram of the bottom blowing system for the steel ladle of this utility model.

[0023] In the picture:

[0024] 1-Gas supply pipe; 2-Gas source device; 301-Gas transmission pipeline; 302-Laval pipe; 303-Gas source connection pipe Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] This utility model relates to a bottom-blowing system for a ladle based on a Laval tube structure. It adds a Laval tube gas supply mechanism 3, consisting of a large-diameter gas delivery pipe 301, a Laval tube 302, and a gas source connection pipe 303, between the gas supply pipe 1 and the gas source device 2 in a traditional bottom-blowing system. Figure 2 As shown.

[0028] The conveying channel 301 is a cylindrical pipe with an inner diameter of 150mm and an axial length of 350mm. The front end of the gas conveying pipe 301 is coaxially welded to the inlet end of the gas supply pipe 1. A circular hole is coaxially opened on the end face of the gas conveying pipe 301 for inserting and installing the gas source connection pipe 303.

[0029] The gas source connecting pipe 303 has an inner diameter of 60mm, is coaxially arranged with the gas conveying pipe 301, and is inserted into the round hole at the end of the gas conveying pipe 301. It is welded and fixed to the round hole in the circumferential direction. The gas source connecting pipe 303 has an inlet end connected to the outlet end of the gas source device 2, and an outlet end connected to the Laval pipe 302.

[0030] The Laval tube 302 is located inside the conveying pipe 201 and is coaxially arranged with the gas source connection pipe 303. The inlet end is welded to the outlet end of the gas source connection pipe 303, and the distance between the outlet end of the Laval tube 302 and the rear end face of the gas conveying channel 301 is 120mm.

[0031] The inlet diameter of the aforementioned Laval tube 302 is 60mm, designed to ensure that gas enters the pipe at a suitable flow rate, guaranteeing sufficient intake volume while avoiding energy loss and airflow instability due to excessive flow velocity. The throat diameter of the Laval tube 302 is 20mm. As the smallest diameter section, the throat is the critical point where the gas velocity transitions from subsonic to supersonic; precise diameter control is essential for generating a stable supersonic airflow. The outlet diameter of the Laval tube 302 is 60mm. This optimized outlet diameter design allows the accelerated supersonic airflow to act optimally on the contact area between the molten steel and the permeable brick, effectively preventing molten steel backflow.

[0032] The Laval tube 302 has a 25mm long contraction section with a 15-degree contraction angle, enabling the subsonic airflow to accelerate uniformly during contraction, laying the foundation for reaching sound speed and entering supersonic mode at the throat. The Laval tube 302 also has a 25mm long expansion section with a 15-degree expansion angle, ensuring that the airflow entering supersonic mode continues to accelerate stably during expansion, thereby generating a powerful and stable upward airflow lifting force.

[0033] In addition, the curvature of the curved section (the arc-shaped part between the contraction and expansion ports) of the Laval tube 302 is designed to be R420mm, which minimizes energy loss and maintains the stability and directionality of the airflow when the gas flows in the tube.

[0034] The aforementioned Laval tubes are manufactured using a special alloy material that is high-strength, high-temperature resistant, and corrosion-resistant. This alloy material is mainly composed of various elements such as chromium and manganese. The manganese content is 0.3%, which gives the Laval tubes excellent high-temperature resistance, enabling them to operate stably for a long time in the high-temperature environment of bottom blowing in a ladle. The chromium content is 12%, which enhances the strength and corrosion resistance of the material, effectively resisting the erosion of molten steel and high-temperature gases, and extending the service life of the Laval tubes.

[0035] This invention introduces a Laval tube gas supply mechanism into a traditional ladle bottom blowing system. Gas originates from the gas source device 2, enters the Laval tube 302 via the gas source connecting pipe 303, and through the unique diameter variation and geometric design of the Laval tube 302, a stable gas flow field is formed at the outlet of the bottom blowing system (gas supply pipe outlet). This gas is then smoothly and evenly blown into the molten steel through the permeable bricks, achieving bottom blowing agitation of the molten steel. This uniform gas distribution promotes full contact and reaction between the molten steel and the gas, significantly improving the uniformity and purity of the molten steel composition. Furthermore, this stable and uniform gas flow field generates a strong and stable upward airflow lifting force, precisely acting on the contact area between the molten steel and the permeable bricks, thereby effectively preventing the molten steel from flowing back into the permeable bricks and fundamentally solving the problem of molten steel backflow clogging the permeable bricks.

Claims

1. A bottom-blowing system for a steel ladle based on a Laval tube structure, characterized in that: A Laval pipe gas supply mechanism is added between the gas supply pipe and the gas source device of the ladle; the Laval pipe gas supply mechanism includes a gas transmission pipeline and a Laval pipe connecting to the gas source. The outlet end of the gas delivery pipeline is coaxially connected to the inlet end of the gas supply pipe. The gas delivery pipeline has a coaxially opened circular hole on the inlet end face, and a gas source connection pipe is coaxially inserted into it. The air source connection pipe is connected to an air source device at its inlet end; The Laval tube is located inside the gas delivery pipeline, with its inlet end coaxially connected to the outlet end of the gas source connection pipe.

2. The bottom blowing system for a steel ladle based on a Laval tube structure as described in claim 1, characterized in that: The gas delivery pipeline has an inner diameter of 150mm and an axial length of 350mm; the gas source connection pipe has an inner diameter of 60mm; and the distance between the outlet end of the Laval pipe and the inlet end of the gas delivery pipeline is 120mm.

3. The bottom blowing system for a steel ladle based on a Laval tube structure as described in claim 1, characterized in that: The inlet and outlet diameters of the Laval tube are 60 mm; the diameter at the throat is 20 mm; the length of the contraction section is 25 mm, and the contraction and expansion angles are 15 degrees; the length of the expansion section is 25 mm; and the overall curvature of the bending section is R420 mm.

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