Thick-film refractory intelligent carbon bricks

Abstract

This invention relates to a thick-film intelligent refractory carbon brick, belonging to the field of blast furnace ironmaking. A thick-film electrical sensor is installed on the carbon brick, stacked layer by layer within the brick and numbered for positioning. Signals from each layer are led out via wires. The electrical state of the thick-film electrical sensor is synchronously affected by the erosion of the carbon brick, and the erosion state of the carbon brick is detected by the resistance signal output by the thick-film electrical sensor. This invention integrates the thick-film electrical sensor in situ onto the surface of the carbon brick, utilizing the corresponding change in output resistance during synchronous erosion to directly reflect the real-time high-temperature erosion of the refractory material inside the blast furnace wall. Compared to the traditional indirect monitoring method of inserting armored thermocouples into blind holes for temperature measurement and combining it with heat transfer model derivation, this method offers better simplicity, accuracy, and reliability, providing important technical support for ensuring the safety of blast furnace ironmaking production and correcting the prediction accuracy of hearth erosion models.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace ironmaking and relates to a thick-film type intelligent refractory carbon brick. Background Technology

[0002] Blast furnace carbon bricks are located inside the blast furnace lining. One end of the carbon brick is in contact with the ironmaking reaction zone inside the blast furnace, while the other end is connected to the furnace shell through a very thin layer of ramming material. The carbon bricks form a container that constrains the reaction within the blast furnace, playing a crucial role in maintaining blast furnace production and ensuring its safety. During blast furnace production, the carbon bricks gradually thin due to the continuous erosion caused by the ironmaking reaction materials and products. Their thickness is considered an important indicator for blast furnace maintenance and ensuring safe production. Therefore, monitoring the thickness of the blast furnace carbon bricks is a core issue for blast furnace production and safety assurance.

[0003] Due to the extremely high temperatures and harsh environment inside the blast furnace, current methods for monitoring the thickness of carbon bricks primarily involve drilling blind holes of varying depths into the carbon bricks, inserting temperature sensors such as sheathed thermocouples, measuring the temperature at each depth, and then indirectly deriving the carbon brick thickness using a heat transfer simulation model. This process requires drilling blind holes through the furnace shell and inserting temperature sensors. Because of inherent errors in temperature measurement, coupled with the difficulty in obtaining perfectly accurate boundary conditions for the heat transfer model, the obtained carbon brick thickness often deviates significantly from the actual thickness. False alarms and missed alarms regarding excess carbon brick thickness can cause substantial losses to the safe operation of the blast furnace. Therefore, blast furnace production urgently needs a direct, accurate, and reliable method for measuring excess thickness. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a thick-film type intelligent refractory carbon brick, which is suitable for online positioning and monitoring of the erosion of refractory materials in the furnace wall during the blast furnace ironmaking process, to ensure production safety and assist in correcting the prediction accuracy of the hearth erosion model, so as to fully and accurately understand the life status of the blast furnace.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A thick-film refractory intelligent carbon brick is provided, in which a thick-film electrical sensor is installed on the carbon brick. The thick-film electrical sensor is stacked layer by layer in the carbon brick and numbered and positioned. The signal of each layer is led out through a wire. The electrical state of the thick-film electrical sensor is synchronously eroded with the erosion of the carbon brick, thus affecting its electrical state. The erosion state of the carbon brick is detected by the resistance signal output by the thick-film electrical sensor.

[0007] Thick-film electrical sensors with multi-layer film structures are prepared on the side surface of carbon bricks using processes such as coating, screen printing, and high-temperature calcination. This forms an integrated thick-film smart carbon brick in situ. The bricks are then stacked layer by layer around the blast furnace wall and numbered and positioned. The signals from each layer are led out through wires. The sensors are synchronously eroded along with the carbon bricks, and their electrical states are updated accordingly. By identifying the resistance output signals, comprehensive online monitoring of the erosion of refractory materials inside the blast furnace is achieved. This helps to correct the prediction accuracy of the mathematical model for blast furnace hearth erosion, providing a comprehensive and accurate understanding of the blast furnace's lifespan and ensuring the safe and reliable production of ironmaking in the blast furnace.

[0008] Optionally, the thick-film electrical sensor includes a first insulating protective layer formed on the carbon brick, a metal functional layer formed by arranging a plurality of resistors on the first insulating protective layer, and a second insulating layer formed on the metal functional layer.

[0009] Optionally, an alumina ceramic slurry is printed onto the carbon brick using a coating process, and then calcined and cured to form a first insulating protective layer.

[0010] Optionally, the metal functional layer is deposited using a screen printing process, selecting chromium or platinum.

[0011] Optionally, a functional film slurry can be applied to the first insulating protective layer using a screen printing process, and then calcined and cured to form a sensor pattern, thus completing the preparation of the metal functional layer.

[0012] Optionally, an alumina ceramic paste is printed onto the metal functional layer using a coating process, and then calcined and cured to form a second insulating protective layer.

[0013] Optionally, the resistance within the metal functional layer includes a plurality of first resistors R connected in parallel. h Each first resistor R h A second resistor R is connected to both sides. l .

[0014] Optional, first resistor R h The length L1 = 200mm, the width B1 = 5mm, and the second resistor R l The length L2 = 10mm and the width B2 = 25mm;

[0015]

[0016] ρ m Where is the resistivity and H is the thickness of the metal functional layer.

[0017] Optionally, after erosion occurs, the output resistance...

[0018] n LThe first resistance R after the carbon brick is eroded h The number.

[0019] Optionally, the surface of the thick-film electrical sensor may be passivated for protection.

[0020] Its implementation method mainly includes the following steps:

[0021] (1) Clean and flatten the side surface of the blast furnace carbon bricks to keep them clean and smooth.

[0022] (2) Alumina ceramic paste is printed on the surface of the treated carbon bricks by a coating process, and then the first insulating protective layer is formed by high-temperature calcination and curing.

[0023] (3) Next, the functional film paste is coated on the first insulating protective layer by screen printing process, and then the sensor pattern is formed by high temperature calcination and curing, thus completing the preparation of the metal functional layer.

[0024] (4) Alumina insulating paste is applied again on the metal functional layer and cured by high temperature to form a second insulating protective layer, thus completing the preparation of the multilayer film structure.

[0025] (5) The surface of the multilayer film sensor is passivated and protected, and finally an integrated thick film type blast furnace intelligent carbon brick is formed.

[0026] (6) Thick film intelligent carbon bricks are stacked layer by layer around the blast furnace wall, and each brick is numbered and positioned. The sensor wires of each layer are led out in a bundled manner. The output resistance value of all intelligent carbon bricks is monitored online. The location and severity of erosion can be determined by locating abnormal signals.

[0027] The beneficial effects of this invention are as follows:

[0028] The intelligent carbon brick of this invention integrates a thick-film electrical sensor in situ onto the surface of the carbon brick. By utilizing the corresponding change in output resistance when synchronous erosion occurs, it directly reflects the real-time high-temperature erosion of the refractory material inside the blast furnace wall. Compared with the traditional indirect monitoring method of inserting armored thermocouples into blind holes for temperature measurement and combining it with heat transfer model derivation, it has better simplicity, accuracy and reliability. It can provide more timely and direct feedback on the location and severity of erosion, providing important technical support for ensuring the safety of blast furnace ironmaking production and correcting the prediction accuracy of hearth erosion models.

[0029] 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

[0030] 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:

[0031] Figure 1 This is a schematic diagram of the sensor's membrane structure;

[0032] Figure 2 This is a schematic diagram of the sensor functional layer circuit structure;

[0033] Figure 3 This is a schematic diagram of a carbon brick in good condition.

[0034] Figure 4 This is a schematic diagram showing the erosion of carbon bricks.

[0035] Figure 5 A schematic diagram of an integrated thick-film intelligent carbon brick for a blast furnace;

[0036] Figure 6 This is the equivalent circuit when the carbon brick is in a good condition.

[0037] Figure 7 This is a circuit diagram illustrating the corrosion of carbon bricks.

[0038] Figure 8 for Figure 7 The equivalent circuit.

[0039] Reference numerals: 1 First insulating protective layer, 2 Second insulating protective layer, 3 Metal functional layer, 31 First resistor, 32 Second resistor, 4 Carbon brick. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Please see Figures 1 to 8 The specific implementation method includes the following steps:

[0044] 1) Clean and level the surface of the blast furnace carbon brick 4 side to keep it clean and smooth. Spray the cleaning agent evenly on the surface of the carbon brick and let it sit for 5-10 minutes to thoroughly penetrate the stains. Then, gently scrub with a soft brush to remove dirt and impurities. Rinse the surface with clean water to thoroughly remove the cleaning agent and stains. Then, wipe it dry with a clean cloth. Note that the surface of carbon brick 4 should be wiped gently to avoid damaging the brick surface.

[0045] 2) Apply alumina ceramic slurry to the surface of the treated carbon brick 4. Note that the alumina particles in the slurry should be high-purity α-alumina, and should be small, spherical, and evenly distributed without agglomeration. The slurry should have good dispersion stability, sintering performance, and fluidity. After high-temperature calcination and curing, the first insulating protective layer 1 is formed. This material can still maintain good insulation performance and has good bonding with the carbon brick under high temperature conditions of 1000℃.

[0046] 3) A metallic Cr or Pt functional film paste is applied to the first insulating protective layer 1 using screen printing. After high-temperature calcination and curing, a sensor pattern is formed, completing the preparation of the metallic functional layer. These two metallic materials have stable electrical properties, with melting points of 1907℃ and 1769℃, respectively, temperature coefficients of resistance of 0.003ppm / ℃ and 0.00374ppm / ℃, and resistivity of 12.9×10⁻⁶. -8 Ω·m and 10.6×10 -8 From the perspectives of signal significance and high-temperature stability, Cr is a more advantageous choice for Ω·m. The specific film structure diagram and functional layer circuit structure are shown below. Figure 1 and Figure 2 As shown, schematic diagrams of the carbon brick in its intact state and when it has undergone erosion are respectively as follows: Figure 3 and Figure 4 As shown.

[0047] When the carbon brick is intact, the output resistance of the metal functional layer is equivalent to Figure 6 Electrical circuit:

[0048] First resistor 31R h The length of the resistor component is L1 = 200mm, the width is B1 = 5mm, and the second resistor is 32R. l The length L2 of the resistor component is 10mm and the width B2 is 25mm, therefore:

[0049]

[0050] In the formula: H is the thickness of the functional layer.

[0051] That is:

[0052] R h >>R l

[0053] At this point, it is equivalent to several resistors connected in parallel, and the output resistance R of the equivalent circuit is... out satisfy:

[0054]

[0055] In the formula: n represents all R h The number of resistors.

[0056] The output resistance of the metal functional layer during carbon brick erosion is equivalent to Figure 7 The diagram is actually equivalent to Figure 8 Electrical circuit:

[0057] The output resistance at this point is:

[0058]

[0059] Where: n L R after erosion of carbon bricks h The number of resistors.

[0060] Therefore, the actual remaining thickness of the carbon brick can be determined by the output resistance value.

[0061] 4) Next, the printed alumina insulating paste is applied again on the metal functional layer. After high-temperature calcination and curing, the second insulating protective layer 2 is formed. This material can still maintain good insulation performance under high temperature conditions of 1000℃ and has good bonding with carbon brick 4, thus completing the preparation of the multilayer film structure.

[0062] 5) The surface of the multilayer film structure sensor is passivated and protected, ultimately forming an integrated thick-film intelligent carbon brick for blast furnaces, such as... Figure 5 As shown.

[0063] 6) Thick-film intelligent carbon bricks are stacked layer by layer around the blast furnace wall, and each brick is numbered and positioned. The sensor wires of each layer are led out in a bundle. The output resistance value of all intelligent carbon bricks is monitored online in real time. The location and severity of erosion can be determined by locating abnormal signals.

[0064] This invention combines in-situ fabrication of thick-film electrical sensors on blast furnace carbon bricks using screen printing technology. The change in output resistance caused by the sensor's synchronous erosion with the brick body provides real-time feedback on the remaining thickness of the carbon bricks, allowing for the assessment and confirmation of the location and extent of furnace wall erosion. Compared to the traditional method of indirectly predicting erosion by inserting armored thermocouples into blind holes in the furnace wall and combining this with heat transfer model calculations, this method offers significantly better simplicity, accuracy, and reliability. It provides crucial technical support for ensuring the safety of blast furnace ironmaking and improving the accuracy of hearth erosion model predictions, making it worthy of widespread application in the metallurgical field. The basic design of this solution is not only applicable to blast furnace scenarios but also to other scenarios requiring refractory bricks and temperature monitoring.

[0065] 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 thick-film type refractory intelligent carbon brick, characterized in that: A thick-film electrical sensor is installed on a carbon brick. The thick-film electrical sensor is stacked layer by layer inside the carbon brick and numbered and positioned. The signal of each layer is led out through a wire. The electrical state of the thick-film electrical sensor is synchronously eroded with the carbon brick, which in turn affects its electrical state. The erosion state of the carbon brick is detected by the resistance signal output by the thick-film electrical sensor. The thick-film electrical sensor includes a first insulating protective layer formed on the carbon brick, a metal functional layer formed by arranging a plurality of resistors on the first insulating protective layer, and a second insulating layer formed on the metal functional layer. Alumina ceramic paste is printed onto the carbon bricks using a coating process, and then calcined and cured to form the first insulating protective layer. The metal functional layer is deposited using a screen printing process, with chromium or platinum as the selected metals. The functional film paste is coated onto the first insulating protective layer using a screen printing process, and then calcined and cured to form a sensor pattern, thus completing the preparation of the metal functional layer; Alumina ceramic paste is printed onto the metal functional layer using a coating process, and then calcined and cured to form a second insulating protective layer. The resistance within the metal functional layer includes several first resistors connected in parallel. Each first resistor A second resistor is connected to both sides. .

2. The thick-film refractory intelligent carbon brick according to claim 1, characterized in that: First resistor length ,width Second resistor length ,width ; ； Resistivity The thickness of the metal functional layer.

3. The thick-film refractory intelligent carbon brick according to claim 2, characterized in that: After erosion occurs, Output resistance ; The first resistance after the carbon brick is eroded The number.

4. The thick-film refractory intelligent carbon brick according to claim 1, characterized in that: The surface of the thick-film electrical sensor is passivated for protection.

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