A ladle baking system and method for changing a baking space in a ladle

Abstract

The application provides a ladle roasting system and method for changing a roasting space in a ladle, and relates to the technical field of steelmaking. The system comprises a burner, a spacing structure and a smoke exhaust pipeline. The spacing structure is fixedly installed on a ladle cover and is located inside the ladle during roasting, so that a first annular space and a second annular space, which are in communication at the bottom, are formed in the ladle. The burner is arranged on the ladle cover and is located above the first annular space during roasting and is in communication with the first annular space. The smoke exhaust pipeline is arranged on the ladle cover and is located above the second annular space during roasting and is in communication with the second annular space. The application adjusts the combustion space of the flame and the flow track and space of the combustion products by adding an inner cylinder in the ladle, so that the flame can directly roast the inner wall of the ladle. By adjusting the smoke flow space, the smoke flow rate is increased, and the roasting speed is greatly increased. The application not only can significantly improve the ladle roasting quality, but also can improve the energy utilization efficiency, and is beneficial to energy saving and consumption reduction of the ladle roasting system.

Description

Technical Field

[0001] This invention relates to the field of steelmaking technology, and more particularly to a ladle baking system and method that alters the baking space inside the ladle. Background Technology

[0002] After tapping from the converter, the high-temperature molten steel needs to be poured into a ladle, which is then transported to refining and continuous casting. Finally, the empty ladle is returned to the converter to await the next heat of molten steel. Throughout this process, the refractory lining of the ladle is in direct contact with the molten steel, absorbing some heat and storing it, while the ladle wall surface dissipates heat to the atmosphere and the molten steel surface, causing a decrease in the molten steel temperature. The temperature of the ladle lining drops significantly, especially during the return process from the continuous casting stage and while waiting to receive molten steel in front of the converter. The temperature of the molten steel drops most rapidly after receiving the steel. Heat loss can be divided into three parts: radiative heat loss from the upper surface of the molten steel, comprehensive heat dissipation loss from the outer surface of the ladle, and heat storage loss from the ladle lining. The heat storage loss from the ladle lining is the largest, accounting for approximately 45%–50% of the total heat loss, followed by heat dissipation from the ladle wall (20%) and radiative heat loss from the upper surface of the ladle (30%–35%). Taking a 100t steel ladle as an example, if the ladle lining temperature is increased from 400℃ to 1200℃, the temperature drop of the molten steel can be reduced by 25-30℃.

[0003] Therefore, to reduce heat loss from molten steel during receiving, the ladle lining needs to be preheated before receiving the steel to increase the lining temperature and reduce the temperature drop of the molten steel after receiving it. Currently, steel companies both domestically and internationally mainly use two types of ladle preheaters: vertical and horizontal. From the perspective of flue gas waste heat utilization, they can be divided into conventional combustion and regenerative preheating methods. However, due to imperfections in these methods, problems exist such as long preheating time, low preheating temperature, poor preheating quality, high energy consumption, and flames failing to reach the bottom of the ladle.

[0004] Patent document CN103447514A discloses a ladle baking device, including an air inlet pipe, a gas inlet pipe, a mixing chamber, and a burner. This invention's structure allows for pre-mixing of air and gas, ensuring complete combustion and reaching the required temperature. Air purification devices are installed on both sides of the baffle plate to absorb post-combustion fumes and prevent air pollution. While this method can play a positive role in improving the baking device and controlling air pollution, it cannot solve the problem of uneven temperature distribution within the ladle.

[0005] Patent document CN207214046U discloses a novel energy-saving ladle baking device, including a ladle body, a ladle cover, and a self-preheating burner. The self-preheating burner is installed in the center of the ladle cover and is embedded, with its lower part extending into the ladle body. The self-preheating burner includes a burner nozzle, a preheating chamber, a gas inlet, and an air inlet. The preheating chamber includes a gas passage, an air passage, and a flue gas passage, with the flue gas passage surrounding the air passage and the gas passage. This utility model patent's ladle baking device utilizes a self-preheating burner to recover high-temperature exhaust gas, reducing fuel consumption. The embedded preheating burner extends the burner and preheating chamber into the ladle baking device, allowing the flame to directly reach the bottom of the ladle, improving heat transfer efficiency. The all-fiber structure of the ladle cover reduces heat absorption and heat dissipation, saving energy. While this patent extends the burner deep into the ladle, allowing the flame to directly bake the bottom, it does not solve the problems of uniform ladle wall temperature and heating rate.

[0006] Patent document CN203330390U discloses a ladle baking device, including a baking ladle cover and a central baker. The central baker is located at the center of the baking ladle cover and has a cylindrical opening. A central burner is located inside the central baker, and 12-15 peripheral burners are evenly distributed circumferentially inside the central baker. Compared with currently used ladle baking devices, this utility model patent features a stronger and longer flame that directly blows onto the bottom of the ladle, then raises the temperature upwards from the bottom, enabling the ladle temperature to be increased within 8-10 minutes. This makes it suitable for online ladle baking, reducing temperature drop and enabling rapid temperature increase. While this patent emphasizes flame rigidity, which is beneficial for heating the bottom of the ladle, it still does not solve the problems of uniform ladle wall temperature and heating speed.

[0007] In summary, current ladle baking technologies, especially vertical ladle baking technologies, suffer from poor uniformity of temperature due to the inability of blast furnace flue gas generated by burners to reach the bottom of the ladle during baking, resulting in large temperature differences between the top and bottom of the ladle. The three patents mentioned above employ different burner designs to address the bottom baking problem, but to achieve the desired baking conditions, the baking time must be extended, leading to energy waste. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a ladle baking system and method that alters the baking space within the ladle. The invention primarily adjusts the combustion space of the flame and the flow trajectory and space of the combustion products by adding an inner cylinder inside the ladle. This allows the flame to directly bake the inner wall of the ladle. By adjusting the flue gas flow space and increasing the flue gas velocity, the baking speed is significantly increased, improving the baking quality of the ladle and solving the problems of incomplete baking and slow baking speed.

[0009] The technical means employed in this invention are as follows: A ladle baking system that alters the baking space inside a ladle includes: a burner, a partition structure, and a flue. The partition structure is fixedly installed on the ladle cover and is located inside the ladle during baking, forming a first annular space and a second annular space with interconnected bottoms inside the ladle. The burner is disposed on the ladle cover and is positioned above the first annular space during baking, communicating with the first annular space. The flue is disposed on the ladle cover and is positioned above the second annular space during baking, communicating with the second annular space.

[0010] Furthermore, the spacer structure includes an inner cylinder and partitions. The top of the inner cylinder is fixed to the ladle cover by fastening bolts. There is a flow space between the bottom of the inner cylinder and the ladle. Partitions are symmetrically arranged between the front and rear sides of the outer wall of the inner cylinder and the inner wall of the ladle. The space between the left side of the inner wall of the ladle, the left side of the outer wall of the inner cylinder, and the two partitions is a first annular space. The space between the right side of the inner wall of the ladle, the right side of the outer wall of the inner cylinder, and the two partitions is a second annular space. The first annular space and the second annular space are connected by the flow space.

[0011] Furthermore, the cover is provided with an atmospheric communication hole, which is connected to the interior of the inner cylinder.

[0012] Furthermore, the radial distance between the outer wall of the inner cylinder and the inner wall of the ladle is 30-100cm.

[0013] Furthermore, the height between the bottom of the outer wall of the inner cylinder and the bottom of the inner wall of the ladle is 20-150cm.

[0014] Furthermore, the inner cylinder is made of the same material as the inner wall of the ladle, or is made of refractory material.

[0015] Furthermore, a smoke exhaust fan is installed on the smoke exhaust duct.

[0016] Furthermore, the number of burners is 3-6, evenly distributed in a ring.

[0017] Furthermore, an infrared thermometer is installed on the cover at a position corresponding to the first annular space and the second annular space, and the detection probe of each infrared thermometer extends through the cover into the interior of the steel ladle.

[0018] The present invention also provides a baking method for a ladle baking system that alters the baking space inside the ladle, comprising the following steps: During baking, the ladle lid is placed on top of the ladle, while the spacer structure falls into the ladle. Fuel is burned through multiple burners, and the resulting flame enters the first annular space. By adjusting the distance between the inner wall of the ladle and the outer wall of the inner cylinder, as well as the number of burners, an annular flame is formed, allowing the flame to directly contact the inner wall of the ladle. The generated high-temperature flue gas flows through the first annular space to the bottom of the ladle, and then flows along the flow space between the outer wall of the inner cylinder bottom and the inner wall of the ladle bottom to the symmetrical second annular space, before being discharged through the exhaust pipe. Throughout the process, the suction force for the high-temperature flue gas is provided by the exhaust fan. During baking, the temperature of the inner wall of the ladle bottom in both annular spaces is monitored in real time using an infrared thermometer. Baking ends when the temperature reaches the preset temperature and the temperature difference is less than or equal to 30°C.

[0019] Compared with the prior art, the present invention has the following advantages: 1. The ladle baking system and method provided by the present invention, which changes the baking space inside the ladle, adjusts the combustion space of the flame and the flow trajectory and space of the combustion products by adding an inner cylinder inside the ladle, so that the flame can directly bake the inner wall of the ladle. By adjusting the flue gas flow space and increasing the flue gas velocity, the baking speed is greatly increased. This not only significantly improves the baking quality of the ladle, but also improves the energy utilization efficiency, which is conducive to energy saving and consumption reduction of the ladle baking system.

[0020] 2. The ladle baking system and method provided by the present invention, which changes the baking space inside the ladle, wherein fuel is burned through multiple burners, and the flame formed by the combustion enters the first annular space to form an annular flame, thereby allowing the flame to directly contact the inner wall of the ladle. The generated high-temperature flue gas flows through the bottom outer wall of the inner cylinder and the partition, flows through the bottom of the ladle, enters the symmetrical second annular space, and is discharged through the exhaust pipe.

[0021] Based on the above reasons, this invention can be widely promoted in fields such as energy conservation in the steel industry. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a cross-sectional view of a ladle baking system that alters the baking space inside the ladle according to the present invention.

[0024] Figure 2 This is a partial top view of a ladle baking system that alters the baking space inside the ladle according to the present invention.

[0025] In the diagram: 1. Steel ladle; 2. Ladle cover; 3. Burner; 4. Fastening bolts; 5. Inner cylinder; 6. Exhaust pipe; 7. Exhaust fan; 8. Flow direction of combustion products from the burner; 9. Atmosphere connection hole; 10. Baffle plate. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0030] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0031] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0032] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0033] Example 1 This invention provides a ladle baking system that alters the baking space inside the ladle, aiming to solve the problems of incomplete baking and slow baking speed. By adding an inner cylinder inside the ladle, the combustion space of the flame and the flow trajectory and space of the combustion products are adjusted, allowing the flame to directly bake the inner wall of the ladle. By adjusting the flue gas flow space and increasing the flue gas velocity, the baking speed is significantly increased, thereby improving the baking effect of the ladle.

[0034] like Figure 1 and Figure 2 As shown, the ladle baking system of the present invention, which changes the baking space inside the ladle, includes: a burner 3, fastening bolts 4, an inner cylinder 5, a flue duct 6, a flue fan 7, a flow direction of combustion products of the burner 8, an atmospheric communication hole 9, and a partition 10.

[0035] The inner cylinder 5 has a cylindrical structure. The top of the inner cylinder 5 is fixed to the cover 2 by fastening bolts 4 and is located inside the ladle 1 during baking. There are partitions 10 symmetrically positioned between the front and rear sides of the outer wall of the inner cylinder 5 and the inner wall of the ladle 1. The material of the inner cylinder 5 can be the same as the inner wall of the ladle 1 or made of refractory materials such as zirconium fiberboard. The fastening bolts 4 are made of heat-resistant alloy steel. An atmospheric communication hole 9 is opened on the cover 2 within the inner cylinder 5, and the atmospheric communication hole 9 is connected to the interior of the inner cylinder 5. There is a flow space between the bottom of the inner cylinder 5 and the ladle 1. The inner cylinder 5 and the partitions 10 divide the interior of the ladle 1 into a first annular space and a second annular space. The space between the left side of the inner wall of the ladle 1, the left side of the outer wall of the inner cylinder 5, and the two partitions 10 is the first annular space. The space between the right side of the inner wall of the ladle 1, the right side of the outer wall of the inner cylinder 5, and the two partitions 10 is the second annular space. The first and second annular spaces are connected by the flow space. The burner 3 is mounted on the lid 2 and is positioned above and connected to the first annular space during baking. The exhaust duct 6 is mounted on the lid 2 and is positioned above and connected to the second annular space during baking. An exhaust fan 7 is mounted on the exhaust duct 6.

[0036] Infrared thermometers (not shown in the figure) are installed on the cover 2 at positions corresponding to the first and second annular spaces. The detection probes of each infrared thermometer extend through the cover 2 into the interior of the ladle 1. The infrared thermometers can be existing structural thermometers, and their models can be selected according to the requirements of the on-site working conditions.

[0037] The process path of this invention is as follows: fuel is burned through multiple burners 3. The flame generated by the combustion enters the first annular space formed by the left side of the outer wall of the inner cylinder 5, the partition 10, and the left side of the inner wall of the ladle 1. The resulting high-temperature flue gas flows through the bottom outer wall of the inner cylinder 5 and the partition 10, through the bottom of the ladle 1, enters the symmetrical second annular space, and is discharged through the exhaust pipe 6. The flow direction of the combustion products of the burners is shown in Figure 8. Figure 1 The arrow in the image points to...

[0038] The method of this invention is as follows: During baking, the lid 2 is placed on top of the ladle 1, while the inner cylinder 5 and the partition 10 fall into the ladle 1. The flame formed by the combustion of fuel through the burners 3 enters the interlayer space (first annular space) between the outer wall of the inner cylinder 5, the partition 10, and the inner wall of the ladle 1, forming an annular flame. The number of burners 3 is 3-6. The annular flame is formed by adjusting the distance between the inner wall of the ladle 1 and the outer wall of the inner cylinder 5 and the number of burners 3, so that the flame directly contacts the inner wall of the ladle 1. The generated high-temperature flue gas flows along the interlayer space between the outer wall of the inner cylinder 5, the partition 10, and the inner wall of the ladle 1 to the bottom of the ladle 1, and flows along the flow space between the bottom outer wall of the inner cylinder 5 and the bottom inner wall of the ladle 1 to the symmetrical second annular space, and is discharged through the exhaust pipe 6. The suction force of the high-temperature flue gas is provided by the exhaust fan 7 throughout the process. During the baking process, the temperature of the bottom inner wall of the ladle 1 in the two annular spaces is detected in real time by an infrared thermometer. When the temperature reaches the preset temperature and the temperature difference is less than or equal to 30°C, the baking ends. The radial distance between the outer wall of the inner cylinder 5 and the inner wall of the ladle 1 is 30-100cm, depending on the shape of the flame, ensuring that the flame can contact the inner wall of the ladle 1 without causing severe erosion. The height between the bottom outer wall of the inner cylinder 5 and the bottom inner wall of the ladle 1 is 20-150cm. Compared with conventional ladle baking methods, this can shorten the baking time by 15% to 40% and reduce fuel consumption by 15% to 30%. An atmospheric connection hole 9 is provided on the ladle cover 2 within the inner cylinder 5. No valves should be installed on the atmospheric connection hole 9 to prevent excessive pressure inside the inner cylinder 5 during ladle baking, which could damage the inner cylinder 5.

[0039] Example 2 A 200t molten steel ladle with a diameter of 3.5 meters and a height of 5 meters is fixed to the ladle cover 2 with an inner cylinder 5 having a diameter of 2.5 meters and a height of 4.5 meters. The bottom outer wall of the inner cylinder 5 is 50cm above the bottom inner wall of the ladle 1. The inner cylinder 5 is made of the same material as the inner wall of the ladle 1 and is fixed to the ladle cover 2 by fastening bolts 4. The ladle is heated by converter gas with a total flow rate of 2000 Nm³. 3 / h, burners 3 are conventional burners. Four burners 3 are evenly arranged in a ring on the cover 2 of the first annular space formed by the outer wall of the inner cylinder 5, the partition 10, and the inner wall of the ladle 1. After the ladle baking begins, the flame formed by the combustion of converter gas through the burners 3 is evenly distributed in the space between the outer wall of the inner cylinder 5, the partition 10, and the inner wall of the ladle 1. The generated high-temperature flue gas flows along the interlayer space between the outer wall of the inner cylinder 5, the partition 10, and the inner wall of the ladle 1 to the bottom of the ladle 1, and then flows along the flow space between the bottom outer wall of the inner cylinder 5 and the bottom inner wall of the ladle 1 to the symmetrical second annular space, and is discharged through the exhaust pipe 6. The suction force of the high-temperature flue gas is provided by the exhaust fan 7 throughout the process. During the baking process, the temperature of the bottom inner wall of the ladle 1 in the two annular spaces is monitored in real time by an infrared thermometer. When the temperature reaches the preset temperature and the temperature difference is less than or equal to 30°C, the baking ends. Compared with the conventional ladle baking method, the baking time can be shortened by 20% and fuel consumption can be reduced by 17%.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ladle baking system that alters the baking space inside the ladle, characterized in that, include: The burner (3), the spacer structure, and the exhaust pipe (6) are provided. The spacer structure is fixedly installed on the cover (2) and is located inside the ladle (1) during baking, so that the ladle (1) forms a first annular space and a second annular space with the bottom connected. The burner (3) is set on the cover (2) and is located above the first annular space during baking, communicating with the first annular space. The exhaust pipe (6) is set on the cover (2) and is located above the second annular space during baking, communicating with the second annular space.

2. The ladle baking system for changing the baking space inside the ladle according to claim 1, characterized in that, The spacer structure includes an inner cylinder (5) and partitions (10). The top of the inner cylinder (5) is fixed to the cover (2) by fastening bolts (4). There is a flow space between the bottom of the inner cylinder (5) and the ladle (1). Partitions (10) are symmetrically arranged between the front and rear sides of the outer wall of the inner cylinder (5) and the inner wall of the ladle (1). The space between the left side of the inner wall of the ladle (1), the left side of the outer wall of the inner cylinder (5) and the two partitions (10) is a first annular space. The space between the right side of the inner wall of the ladle (1), the right side of the outer wall of the inner cylinder (5) and the two partitions (10) is a second annular space. The first annular space and the second annular space are connected by the flow space.

3. The ladle baking system for changing the baking space inside the ladle according to claim 2, characterized in that, The cover (2) has an atmospheric communication hole (9) which is connected to the interior of the inner cylinder (5).

4. The ladle baking system for changing the baking space inside the ladle according to claim 2, characterized in that, The radial distance between the outer wall of the inner cylinder (5) and the inner wall of the ladle (1) is 30-100cm.

5. The ladle baking system for changing the baking space inside the ladle according to claim 2, characterized in that, The height between the bottom of the outer wall of the inner cylinder (5) and the bottom of the inner wall of the ladle (1) is 20-150cm.

6. The ladle baking system for changing the baking space inside the ladle according to claim 2, characterized in that, The inner cylinder (5) is made of the same material as the inner wall of the steel ladle (1), or is made of refractory material.

7. The ladle baking system for changing the baking space inside the ladle according to claim 1, characterized in that, A smoke exhaust fan (7) is installed on the smoke exhaust pipe (6).

8. The ladle baking system for changing the baking space inside the ladle according to claim 1, characterized in that, The number of burners (3) is 3-6, and they are evenly distributed in a ring.

9. The ladle baking system for changing the baking space inside the ladle according to claim 1, characterized in that, Infrared thermometers are installed on the cover (2) at positions corresponding to the first and second annular spaces, and the detection probes of each infrared thermometer extend through the cover (2) into the interior of the steel ladle (1).

10. A baking method for a ladle baking system that alters the baking space inside the ladle as described in any one of claims 1-9, characterized in that, Includes the following steps: During baking, the lid (2) is placed on top of the ladle (1), and the spacer structure falls into the ladle (1). The fuel is burned through multiple burners (3). The flame formed by the combustion enters the first annular space. By adjusting the distance between the inner wall of the ladle (1) and the outer wall of the inner cylinder (5) and the number of burners (3), an annular flame is formed so that the flame directly contacts the inner wall of the ladle (1). The generated high-temperature flue gas flows to the bottom of the ladle (1) through the first annular space and flows along the flow space between the bottom outer wall of the inner cylinder (5) and the bottom inner wall of the ladle (1) to the symmetrical second annular space, and is then discharged through the exhaust pipe (6). The suction force of the high-temperature flue gas is provided by the exhaust fan (7) throughout the process. During the baking process, the temperature of the bottom inner wall of the ladle (1) in the two annular spaces is detected in real time by an infrared thermometer. When the temperature reaches the preset temperature and the temperature difference is less than or equal to 30°C, the baking ends.

Images