Hot blast stove using blast furnace gas as energy source

Abstract

The present application relates to a kind of hot blast furnace with blast furnace gas as energy source, including furnace body, furnace body includes corrosion-resistant furnace shell, acid-resistant heat insulation layer, fiber buffer layer and working layer in turn from outside to inside, wherein, corrosion-resistant furnace shell has the performance of acid root corrosion resistance, acid-resistant heat insulation layer is used to heat insulation and block the contact of corrosive gas with corrosion-resistant furnace shell, fiber buffer layer is used to absorb the expansion displacement of working layer.The furnace body of the present application includes corrosion-resistant furnace shell, acid-resistant heat insulation layer, fiber buffer layer and working layer in turn from outside to inside, wherein, fiber buffer layer can absorb the expansion displacement of working layer, and reduce the total amount of hot blast transmitted outward through furnace body, acid-resistant heat insulation layer has good heat insulation effect, while reducing the contact of acid root with furnace shell, furnace shell uses corrosion-resistant furnace shell, so as to have good heat insulation effect, while having good corrosion resistance, so as to improve the durability of furnace shell.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a hot blast stove that uses blast furnace gas as its energy source. Background Technology

[0002] With the rapid development of the ironmaking industry, high pressure and high blast temperature have become a trend in ironmaking technology development. Traditional hot blast stoves powered by blast furnace gas, after years of operation at high blast temperatures, will inevitably experience cracking, overheating, and air leakage. In particular, the high-temperature section (including the dome) of the hot blast stove experiences significant horizontal and vertical expansion, and the stove's outer shell cannot withstand the corresponding high stress, leading to cracks and air leakage. Furthermore, the hot blast stove shell operates under highly alternating conditions, with the high-pressure gas and thermal expansion of the furnace lining causing biaxial stress that extends vertically upwards and horizontally along the radius. The maximum stress is distributed in the upper high-temperature region of the furnace lining. Since the hot blast stove operates under alternating heating and blasting conditions, the internal pressure is cyclical, with the blast pressure during blasting ranging from 0.4 to 0.5 MPa. When the combustion air and gas enter the hot blast stove for combustion and heat conversion, the pressure is only about 0.01 MPa. Therefore, the furnace shell is often subjected to repeated pressure differences of 40 to 50 times, which will reduce the strength and durability of the furnace shell.

[0003] The stress in the hot blast stove shell includes the internal forces of the shell membrane, equipment loads and external forces such as wind, snow, and earthquakes, as well as the thermal stress of the hot blast stove, wind pressure, alternating stress, and repeated stresses such as thermal expansion stress. Among these, since the air temperature at the top of the hot blast stove exceeds 1300℃, it produces gases with high concentrations of nitrate ions, which may come into direct contact with the inner wall of the furnace shell. Under the action of high-pressure gas and thermal expansion of the furnace lining, special intergranular stress corrosion occurs. The combined effect of this corrosion and tensile stress can lead to cracks in the furnace shell. The cracks formed between the crystals weaken the strength of the furnace shell, thereby reducing its lifespan. This has a fatal impact on the durability of the furnace shell. Summary of the Invention

[0004] In order to solve all or part of the above problems, the present invention aims to provide a hot blast stove that uses blast furnace gas as energy. The furnace body of the present invention has a better heat insulation effect, while reducing the contact between acid radicals and the furnace shell, and has better corrosion resistance, thereby improving the durability of the furnace shell.

[0005] According to one aspect of the present invention, a hot blast stove using blast furnace gas as energy is provided, comprising a furnace body, the furnace body comprising, from the outside to the inside, a corrosion-resistant furnace shell, an acid-resistant heat insulation layer, a fiber buffer layer and a working layer, wherein the corrosion-resistant furnace shell has the property of resisting acid radical corrosion, the acid-resistant heat insulation layer is used for heat insulation and blocking the contact between corrosive gases and the corrosion-resistant furnace shell, and the fiber buffer layer is used for absorbing the expansion displacement of the working layer.

[0006] Furthermore, the corrosion-resistant furnace shell is formed by connecting several composite plates through a coating welding method. Each composite plate includes an outer layer of Q355C steel plate and an inner layer of 904L super austenitic stainless steel plate. The Q355C steel plate and the 904L super austenitic stainless steel plate are composite formed by explosive bonding.

[0007] Furthermore, the acid-resistant heat insulation layer includes an anti-intergranular corrosion coating layer, an acid-resistant sprayed protective layer, and a heat insulation layer arranged sequentially from the outside to the inside. The anti-intergranular corrosion coating layer is applied to the inner wall of the corrosion-resistant furnace shell, and the acid-resistant sprayed protective layer abuts against the anti-intergranular corrosion coating layer. The acid-resistant sprayed protective layer is connected to the corrosion-resistant furnace shell by anchoring hooks. The thickness of the 904L super austenitic stainless steel plate is 3-4 mm.

[0008] Furthermore, the heat insulation layer comprises two masonry layers with staggered brick joints. The horizontal brick joints of the outer masonry layer are staggered from the horizontal welds of the composite board, and the outer masonry layer abuts against the acid-resistant sprayed protective layer.

[0009] Furthermore, the fiber buffer layer has a thickness of 120-160 mm and a thermal conductivity of 0.15 W / (1 m·600 °C); the fiber buffer layer can be compressed to 20% of its initial volume.

[0010] Furthermore, the working layer includes an inner masonry layer, each layer of which is composed of several bricks connected along the circumference in a manner of interlocking grooves and protrusions, and the arched area of ​​the inner masonry layer is catenary-shaped; each layer of the inner masonry layer is provided with several furnace expansion joints along the height direction, and each furnace expansion joint is filled with combustible material; each layer of the inner masonry layer is also provided with several furnace body expansion joints, which are parallel and equal-width joints in the vertical section with uniform cross-section, and equal-width joints with interlocking grooves and protrusions in the dome section with variable cross-section.

[0011] Furthermore, the working layer also includes an inner heat insulation layer, which is disposed between the inner masonry and the fiber buffer layer. The inner heat insulation layer comprises several layers of masonry arranged sequentially from the outside to the inside, and each layer of masonry is uniformly provided with several longitudinal expansion joints along the circumferential direction. The furnace expansion joint accounts for more than 60% of the sum of the furnace expansion joint and the furnace body expansion joint.

[0012] Furthermore, the hot air furnace also includes a hot air pipe, and vector expansion joints are provided at the variable cross-section and / or variable angle of the working layer of the hot air pipe. The vector expansion joint is formed by connecting axial expansion joints and radial expansion joints, and a fiber blanket is provided at each vector expansion joint. The width of the vector expansion joint is 8-12 mm, and the thermal conductivity of the fiber blanket is 0.21 W / (1m·600℃). A pipe expansion joint cover brick is provided on the outside of each vector expansion joint.

[0013] Furthermore, an axial expansion joint is provided at the hot air outlet of the furnace body. The axial expansion joint is used to accommodate the expansion of the lining at the hot air outlet along the axis of the hot air outlet. The axial expansion joint is filled with fiber felt. Each layer at the hot air outlet of the furnace body along the axis of the hot air outlet is also provided with several radial expansion joints. Each radial expansion joint is filled with fiber felt and each radial expansion joint is in the form of a concave-convex fit.

[0014] Furthermore, stress monitoring points and temperature monitoring points are provided on the outer side of the furnace body.

[0015] As can be seen from the above technical solution, the hot blast stove using blast furnace gas as an energy source provided by the present invention has the following beneficial effects:

[0016] The furnace body of the present invention includes a corrosion-resistant furnace shell, an acid-resistant heat insulation layer, a fiber buffer layer, and a working layer arranged sequentially from the outside to the inside. The fiber buffer layer can absorb the expansion displacement of the working layer and reduce the total amount of hot air transferred outward through the furnace body. The acid-resistant heat insulation layer has a good heat insulation effect and reduces the contact between acid radicals and the furnace shell. The furnace shell is made of corrosion-resistant material, which has a good heat insulation effect and good corrosion resistance, thereby improving the durability of the furnace shell. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a hot blast stove that uses blast furnace gas as an energy source according to an embodiment of the present invention;

[0018] Figure 2 This is a cross-sectional view of the furnace body portion according to an embodiment of the present invention;

[0019] Figure 3 This is a cross-sectional view of the hot air duct in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the temperature and stress monitoring section in an embodiment of the present invention.

[0021] Figure 5 This is another cross-sectional view of the furnace body portion according to an embodiment of the present invention;

[0022] Figure 6 A schematic diagram showing the installation of expansion joints between the inner masonry and the furnace body.

[0023] The attached diagram is labeled as follows: 1. Corrosion-resistant furnace shell; 2. Acid-resistant insulation layer; 21. Anti-intergranular corrosion coating layer; 22. Acid-resistant spray protective layer; 23. Insulation layer; 3. Fiber buffer layer; 4. Working layer; 41. Inner lining insulation layer; 42. Inner masonry; 5. Vector expansion joint; 51. Pipe expansion joint cover brick; 6. Axial expansion joint; 7. Combustion chamber axis; 8. Hot air outlet axis; 9. Regenerator axis; 10. Hot air outlet; 11. Furnace drying expansion joint; 12. Furnace body expansion joint. Detailed Implementation

[0024] To better understand the purpose, structure, and function of this invention, a hot blast stove using blast furnace gas as an energy source will be described in further detail below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, this invention illustrates a hot blast stove powered by blast furnace gas, comprising a furnace body. The furnace body includes, from the outside to the inside, a corrosion-resistant furnace shell 1, an acid-resistant heat insulation layer 2, a fiber buffer layer 3, and a working layer 4. The corrosion-resistant furnace shell 1 is resistant to acid radical corrosion, the acid-resistant heat insulation layer 2 is used for heat insulation and to prevent contact between corrosive gases and the corrosion-resistant furnace shell 1, and the fiber buffer layer 3 is used to absorb the expansion displacement of the working layer 4.

[0026] In practical implementation, the corrosion-resistant furnace shell 1, acid-resistant insulation layer 2, fiber buffer layer 3, and working layer 4 of this embodiment can be installed in the high-temperature area of ​​the hot blast stove (e.g., where the internal temperature of the furnace body reaches above 700 degrees Celsius). The hot blast stove of this embodiment can achieve excellent insulation performance with an external furnace shell temperature below 96 degrees Celsius while meeting the requirements of ultra-high blast temperature output of 1250-1300 degrees Celsius. (Reference) Figure 5 The high-temperature zone of the hot air furnace can also be the area centered on the hot air outlet axis 8, the regenerator axis 9, and the combustion chamber axis 7.

[0027] Specifically, corrosion failure in the high-temperature section of a hot blast stove typically manifests as pitting corrosion perforation and stress corrosion cracking. When the supply air temperature remains above 1300 degrees Celsius for an extended period, the temperature at the top of the hot blast stove reaches 1420-1450 degrees Celsius, and the flame temperature during combustion exceeds 1500 degrees Celsius. This leads to the combination of nitrogen in the combustion air and coal gas to form nitrogen oxides (NOx). X The combustion of sulfur in combustion air and coal gas forms sulfur oxides (SO₄). X These oxides react with condensed water to form a mixture of nitric acid, nitrous acid, sulfuric acid, and sulfurous acid. Some of this mixture may be carried in by the hot air and corrode the furnace shell steel plate. The corrosion of the furnace shell steel plate is essentially caused by these acids forming electrolytes on the steel plate surface, which have a high potential and erode the steel plate under electrochemical action.

[0028] In this embodiment, the outermost layer of the furnace body is a corrosion-resistant furnace shell 1, which has the property of resisting acid radical corrosion.

[0029] Specifically, the corrosion-resistant furnace shell 1 is composed of several composite plates connected by a cladding welding method. Each composite plate includes an outer layer of Q355C steel plate and an inner layer of 904L super austenitic stainless steel plate. The Q355C steel plate and the 904L super austenitic stainless steel plate are composite formed by explosive bonding.

[0030] 904L super austenitic stainless steel plate is a low-carbon, highly alloyed austenitic stainless steel designed for corrosive environments, exhibiting excellent corrosion resistance. It also demonstrates excellent resistance to stress corrosion, pitting corrosion, and crevice corrosion caused by acid radicals, and possesses good resistance to intergranular corrosion. For a furnace shell in operation, it experiences both tensile stress and is subjected to NO₂. X and SO X Intergranular corrosion damages the intergranular bonds in the steel plate, causing cracks in the lining steel plate of the hot blast stove. These cracks extend along the grain boundaries into the steel matrix. Therefore, taking measures to prevent intergranular corrosion is an important factor in selecting materials for the furnace shell in the high-temperature section. The 904L super austenitic stainless steel plate in this embodiment has excellent resistance to intergranular corrosion.

[0031] The chemical composition of 904L super austenitic stainless steel is shown in Table 1 below, and the mechanical properties of 904L super austenitic stainless steel are shown in Table 2 below.

[0032] Table 1: Chemical Composition of 904L Super Austenitic Stainless Steel

[0033] %content Ni Cr Mo Cu Fe C Mn Si P S Minimum 23 19 4 1 margin - - - - - maximum 28 23 5 2 - 0.02 2 1 0.035 -

[0034] Table 2: Mechanical Properties of 904L Super Austenitic Stainless Steel

[0035] Stainless steel models Tensile strength (MPa) Yield strength MPa Elongation % 904L 490 216 35

[0036] 904L super austenitic stainless steel has a high nickel content and contains 1-2% copper, exhibiting excellent corrosion resistance to reducing acids such as sulfuric acid and phosphoric acid, thus reducing the corrosion rate of the furnace body in pits and crevices. Ordinary austenitic stainless steel may be sensitive to stress corrosion cracking in a chloride-rich environment at temperatures above 60 degrees Celsius. This embodiment uses 904L super austenitic stainless steel with an increased nickel content, which reduces this sensitization. Tests have shown that 904L super austenitic stainless steel plates exhibit high resistance to stress corrosion cracking in acidic environments. The corrosion resistance of the 904L super austenitic stainless steel plates used in this embodiment is three times that of ordinary carbon steel.

[0037] Furthermore, the corrosion-resistant furnace shell 1 is composed of several composite plates connected by a cladding welding method. Each composite plate includes an outer layer of Q355C steel plate and an inner layer of 904L super austenitic stainless steel plate. The Q355C steel plate and the 904L super austenitic stainless steel plate are composite formed by explosive bonding. After welding, annealing is used to eliminate welding stress, which greatly reduces the corrosive gas and liquid atmosphere formed in the high-temperature area of ​​the hot blast stove and its impact on the intergranular stress corrosion damage of the furnace shell. This gives the furnace shell good corrosion resistance and extends the service life of the hot blast stove. The service life of the hot blast stove in this embodiment can reach 40-50 years.

[0038] As an alternative, a composite plate of Q355C and 904L can be formed by rolling using 904L super austenitic stainless steel as the base material. The thickness of the 904L super austenitic stainless steel plate is 3-4 mm.

[0039] Among them, the acid-resistant heat insulation layer 2 is used for heat insulation and to prevent corrosive gases from contacting the corrosion-resistant furnace shell 1. Specifically, for example... Figure 2 As shown, the acid-resistant heat insulation layer 2 includes an anti-intergranular corrosion coating layer 21, an acid-resistant sprayed protective layer 22, and a heat insulation layer 23 arranged sequentially from the outside to the inside. The anti-intergranular corrosion coating layer 21 is coated on the inner wall of the corrosion-resistant furnace shell 1. The acid-resistant sprayed protective layer 22 abuts against the anti-intergranular corrosion coating layer 21 and is connected to the corrosion-resistant furnace shell 1 by anchoring hooks.

[0040] Specifically, the anti-intergranular corrosion coating layer 21 is directly applied to the inner wall of the composite plate to prevent the high-temperature corrosive gases generated during the operation of the hot blast stove from contacting the furnace shell. The acid-resistant spray protective layer 22 is connected to the insulation layer 23 by a top-mounting method. The good insulation performance can not only reduce the heat loss of the hot blast stove, but also reduce the thermal stress of the furnace shell system. The vertical masonry method reduces the risk of hot air directly leaking out of the high-temperature area of ​​the hot blast stove.

[0041] The acid-resistant spray protective layer 22 is closely attached to the anti-intergranular corrosion coating layer 21, and the acid-resistant spray protective layer 22 is connected to the corrosion-resistant furnace shell 1 by anchoring hooks, eliminating the damage to the furnace shell caused by high air temperature; the acid-resistant spray protective layer 22 has heat insulation capability, eliminating the damage caused by hot air at temperatures up to 1300 degrees when in direct contact with the furnace shell.

[0042] The insulation layer 23 includes two masonry layers with staggered brick joints. The horizontal brick joints of the outer masonry layer are staggered with the horizontal welds of the composite board. The outer masonry layer is in contact with the acid-resistant sprayed protective layer 22.

[0043] Specifically, the refractory bricks of the insulation layer 23 need to meet the following requirements: a reheat linear change of 0.2% after burning at 1600 degrees Celsius for two hours, and a thermal conductivity (350℃) of 0.308 units (W / (m·K)). The insulation layer 23 consists of two layers of masonry, with all horizontal brick joints of the two layers staggered by 30 mm to prevent hot air leakage. The horizontal welds of the furnace shell in the same area are also staggered from the horizontal brick joints of the outer layer, for example, by 60 mm. Furthermore, the outer layer of masonry abuts against the acid-resistant sprayed protective layer 22.

[0044] The fiber buffer layer 3 has a thickness of 120-160 mm and a thermal conductivity of 0.15 W / (1 m·600℃); the fiber buffer layer 3 can be compressed to 20% of its initial volume.

[0045] Specifically, the fiber buffer layer 3 absorbs the free expansion displacement of the working layer 4 of the hot blast stove, reduces the stress transmission of the thermal expansion deformation of the working layer 4 to the corrosion-resistant furnace shell 1, and at the same time improves the heat insulation performance of the lining of the high-temperature section of the hot blast stove and increases resource utilization.

[0046] The fiber buffer layer 3 is used to absorb the deformation of the working layer 4, reduce external heat dissipation, attenuate high alternating stress under operating conditions, and eliminate local stress concentration. The fiber buffer layer 3 is a stress-absorbing buffer layer of the hot blast stove body that is in close contact with the working layer 4. The fiber buffer layer 3 has a thickness of 120-160 mm, a thermal conductivity of 0.15 W / (1 m·600℃), and a compressibility of 20%. It can completely absorb the deformation and stress transmitted by the working layer 4, basically eliminate the structural thermal stress transmitted by the working layer 4 to the outside, and also ensure that the thermal insulation performance of the fiber buffer layer 3 remains at the initial planned value during the mid-term operation of the hot blast stove. The fiber buffer layer 3 allows for free expansion of the inner layer of the hot blast stove body.

[0047] Among them, such as Figure 2 As shown, the working layer 4 includes an inner masonry layer 42. Each layer of the inner masonry layer 42 along the height direction is composed of several bricks connected along the circumferential direction in the form of grooves and protrusions. The arched area of ​​the inner masonry layer 42 is catenary-shaped.

[0048] Specifically, the working layer 4 is the refractory lining inside the hot blast stove that directly contacts the combustion process during the conversion of blast furnace gas into heat energy. Each layer of the inner masonry 42 of the high-temperature working layer is composed of several bricks connected along the circumference in a manner of interlocking grooves and protrusions. Specifically, each brick has both a groove and a protrusion; the groove of one brick engages with the protrusion of the next brick, and the protrusion engages with the groove of the previous brick. For the inner masonry, each layer along the height direction is a ring structure composed of several bricks connected by interlocking grooves and protrusions.

[0049] The arched area of ​​the inner masonry 42 of the high-temperature working layer is catenary-shaped, which can greatly improve the stability of the inner masonry of the high-temperature working layer. The inner masonry 42 of the high-temperature working layer includes two layers, inner and outer, and the vertical and horizontal brick joints of the inner and outer layers are all staggered, thereby eliminating the hidden danger of high-temperature gas directly leaking to the outside.

[0050] The working layer 4 must withstand high temperatures in the range of 1180-1420 degrees Celsius, and the deformation and stress are extremely large. Therefore, this embodiment adopts a connection form with grooves and protrusions that cooperate with each other. While bearing the periodic axial and radial expansion values ​​caused by temperature changes, it still ensures the overall stability of the hot blast furnace lining structure.

[0051] In one specific embodiment, such as Figure 6 As shown, each layer of the inner masonry 42 along the height direction of the working layer is provided with several furnace expansion joints 11, and each furnace expansion joint 11 is filled with combustible material; each layer of the inner masonry 42 along the height direction is also provided with several furnace body expansion joints 12, the furnace body expansion joints 12 are parallel and equal-width joints in the vertical section with equal cross-section, and the furnace body expansion joints are equal-width joints with grooves and protrusions in the dome section with variable cross-section.

[0052] Specifically, the inner masonry of the working layer can be considered as several layers stacked together along the height direction. The furnace expansion joint 11 is located in the inner masonry of the working layer and is in direct contact with the hot blast stove's combustion and air supply atmosphere. The furnace expansion joint is filled with combustible material. The gap formed after the combustible material is completely burned during the furnace drying process is the furnace expansion joint. The furnace expansion joint 11 can absorb part of the circumferential expansion of the inner lining masonry under the hot blast stove's operating conditions and is an irreversible expansion joint. Furthermore, the furnace expansion joint 11 is centered on the axis of the regenerator chamber and the axis of the combustion chamber.

[0053] Each layer of the inner lining masonry 42 in the secondary working layer is also provided with several furnace body expansion joints 12 along the height direction. The furnace body expansion joints 12 adopt different structures in the vertical section with constant cross-section and the dome section with variable cross-section of the inner lining masonry 42. Specifically, the vertical section with constant cross-section means that the masonry layer has a single diameter from top to bottom along the height direction, while the dome section with variable cross-section means that the masonry layer has multiple diameters from top to bottom along the height direction. In specific configuration, the furnace body expansion joints 12 in the vertical section with constant cross-section are parallel joints of equal width, while the furnace body expansion joints 12 in the dome section with variable cross-section are joints of equal width with grooves and protrusions engaging.

[0054] The furnace body expansion joint 12, centered on the regenerator axis 9 and the combustion chamber axis 7, is divided into two parts: the regenerator region and the combustion chamber region. The lining structure within the combustion chamber region is independently situated on the furnace shell support ring. The furnace body expansion joint in the combustion chamber is separated from the regenerator furnace body expansion joint by a distance of two bricks, with a horizontal spacing of 10-20 mm. The furnace body expansion joint is densely filled with high-temperature fiber. This expansion joint absorbs the deformation caused by the mixing force of air and gas on the lining axis during combustion, eliminating the risk of high-temperature gas leakage. Utilizing the approximately 40% compressibility of the high-temperature fiber, it not only absorbs the circumferential expansion of the hot blast stove lining system but also automatically rebounds when the lining shrinks during the temperature drop period of the hot blast stove, cutting off the gas channel from the hot blast stove directly to the furnace shell steel plate, thus maintaining the stability of the hot blast stove lining system. Based on the temperature change from inside to outside the furnace, the furnace body is divided into the inner working ring, the auxiliary middle ring, and the heat insulation outer ring from inside to outside the furnace shell. The spaces between adjacent rings are filled with 1000-1400 degree high-temperature fiber felt, but the expansion joints of the fiber felt in each ring must not be connected, and the horizontal distance must be greater than or equal to 40 mm.

[0055] Among them, such as Figure 2 As shown, the working layer 4 also includes an inner heat insulation layer 41, which is disposed between the inner masonry and the fiber buffer layer 3. The inner heat insulation layer 41 includes several layers of masonry arranged sequentially from the outside to the inside, and each layer of masonry is uniformly provided with several longitudinal expansion joints along the circumferential direction.

[0056] The inner lining insulation layer 41 withstands temperatures of approximately 800-1000 degrees Celsius and does not directly participate in the combustion and heat conversion of gas in the hot blast stove; its primary function is heat insulation. The inner lining insulation layer 41 is positioned between the inner masonry layer and the fiber buffer layer 3. The inner lining insulation layer 41 comprises several layers of masonry arranged sequentially from the outside in. Each layer of masonry has several longitudinal expansion joints evenly distributed along its circumference, for example, one longitudinal expansion joint every 600 millimeters along the circumference. This eliminates stress concentration and ensures that the horizontal expansion of the working layer 4 is extremely low under 1400°C operating conditions.

[0057] In specific configurations, the oven expansion joint 11 accounts for more than 60% of the sum of the oven expansion joint 11 and the furnace body expansion joint 12.

[0058] Furthermore, an axial expansion joint is provided at the hot air outlet 10 of the furnace body. The axial expansion joint is used to accommodate the expansion of the inner lining at the hot air outlet 10 along the axis of the hot air outlet. The axial expansion joint is filled with fiber felt. Several radial expansion joints are also provided at each layer of the hot air outlet 10 along the axis of the hot air outlet. Each radial expansion joint is filled with fiber felt and each radial expansion joint is in the form of a concave-convex fit.

[0059] When the hot blast stove is in the air supply state, high-temperature hot air enters the blast furnace from the hot blast outlet 10 through the hot blast pipe and the hot blast enclosure pipe. That is, the hot blast outlet 10 is located between the furnace body and the hot blast pipe. In this embodiment, an axial expansion joint and a radial expansion joint are provided at the hot blast outlet 10.

[0060] Specifically, the lining at the hot air outlet 10 is divided into several layers along the hot air outlet axis, with axial expansion joints placed between adjacent layers to accommodate the expansion of the lining at the hot air outlet along the hot air outlet axis. The axial expansion joints are parallel and of equal width, filled with 1400-degree high-temperature fiber felt. This meets the requirements for absorbing the axial expansion of the hot air outlet lining system. Furthermore, when the hot air stove is in the firing stage, the high-temperature fiber felt automatically rebounds when the lining shrinks, cutting off the gas channel from the hot air outlet to the furnace shell, reducing the deformation of the inner material and furnace shell structure at the hot air outlet during operation, and achieving the goal of maintaining stable stress at the hot air outlet.

[0061] Radial expansion joints are installed in each layer along the hot air outlet axis. Specifically, several radial expansion joints are also provided in each layer along the hot air outlet axis of the furnace body. The radial expansion joints are in a concave-convex fit and are filled with 1400-degree high-temperature fiber felt to meet the requirements for absorbing the radial expansion of the hot air outlet lining system. Moreover, when the hot air furnace is in firing condition, the high-temperature fiber felt automatically rebounds when the lining shrinks, cutting off the gas channel for high-temperature gas from the hot air outlet to directly enter the furnace shell, preventing the inner ring brick of the hot air outlet from tilting into the furnace, and achieving the goal of maintaining the stability of the stress at the hot air outlet. The measures for dealing with the expansion deformation of the lining in the high-temperature area of ​​the hot air furnace in this embodiment include radial pre-reserved gaps, vertical autonomous expansion deformation control, and asymmetric and uneven expansion deformation control at variable cross-section and furnace shell openings.

[0062] Among them, such as Figure 3 As shown, the hot air furnace also includes a hot air pipe. Vector expansion joints 5 are provided at the variable cross-section and / or variable angle of the working layer of the hot air pipe. The vector expansion joints 5 are formed by connecting axial expansion joints and radial expansion joints. A fiber blanket is provided at each vector expansion joint 5.

[0063] Specifically, when the hot blast stove is in the air supply state, high-temperature hot air enters the blast furnace from the hot blast outlet through the hot blast pipe and the hot blast casing. During this process, the hot blast pipe undergoes irregular deformation due to stress caused by high pressure, high temperature, and temperature difference deformation. In existing technologies, expansion joints are theoretically installed at the three-way junctions of the hot blast pipe and at the bends of the pipe system. However, because the expansion joints installed in the traditional way do not properly consider the effects of stress, expansion amount, and alternation cycle in different directions, the above-mentioned parts are prone to high temperature, red-hot, and gas leakage failures. This invention provides vector expansion joints 5 at the variable cross-section and / or variable angle of the working layer of the hot blast pipe. The vector expansion joints 5 are formed by connecting axial expansion joints and radial expansion joints, thereby eliminating the expansion amount of the hot blast pipe at the variable interface and variable angle, and achieving the purpose of keeping the hot blast pipe under low stress; the simple axial expansion joint 6 is not required.

[0064] In this embodiment, the width of the vector expansion joint 5 is 8-12 mm, and it is filled with an integral fiber blanket. The thermal conductivity of the fiber blanket is 0.21 W / (1m·600℃).

[0065] Among them, such as Figure 3 As shown, each vector expansion joint 5 is provided with a pipe expansion joint cover brick 51 on its outer side.

[0066] In this embodiment, each vector expansion joint 5 is provided with a pipe expansion joint cover brick 51 on its outer side. The pipe expansion joint cover brick 51 is made of high-strength heavy brick of the same material as the high-temperature working area inside the pipe. This eliminates the micro-cracks, cracks, and even failures caused by the use of lightweight bricks in the original pipe system structure. In this embodiment, the strength of the pipe expansion joint cover brick 51 is 55-65 MPa.

[0067] The furnace body is equipped with stress monitoring points and temperature monitoring points on its exterior.

[0068] Specifically, stress monitoring points and temperature monitoring points are set in high-stress, high-temperature areas outside the hot blast stove body.

[0069] like Figure 4 As shown, the data from stress monitoring points and temperature monitoring points are transmitted to the temperature / stress data analysis system via a remote data transmission unit, and the temperature / stress data analysis system provides feedback and alarms through analysis.

[0070] By setting up stress and temperature monitoring points, constructing a sensor network and a field distributed data acquisition system, and using digital signals for remote data transmission, the system analyzes the long-term stress state of the hot blast stove body based on measured stress state and fatigue life mathematical models and load monitoring mathematical models. Based on the analysis results, the system realizes automatic early warning and alarm, which not only enables remote real-time monitoring of the safety status of the hot blast stove body, but also timely warning of risks and timely information push, forming a remote intelligent safety monitoring system.

[0071] By setting up stress and temperature monitoring points, the system effectively monitors the stress and deformation parameters of key areas, truly achieving the goal of low stress in long-cycle hot blast stove systems. This system enables remote, intelligent, and safe control of the hot blast stove through mechanical parameters, based on the theoretical foundation of the stove's mechanical behavior. By optimizing the configuration of mechanical sensors, a sensor network and a distributed data acquisition system were constructed, utilizing 4G / 5G signals for remote transmission. Based on mathematical models of temperature, stress state, fatigue life, and load monitoring, automatic early warning and alarms are achieved through simulation analysis. This allows for the analysis of the stress state of the hot blast stove body, enabling not only remote real-time monitoring of the stove shell's safety status but also timely risk warnings.

[0072] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0073] Furthermore, the terms "a," "two," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0074] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0075] 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 therein. 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, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A hot blast stove using blast furnace gas as an energy source, characterized in that, The furnace body includes, from the outside to the inside, a corrosion-resistant furnace shell, an acid-resistant heat insulation layer, a fiber buffer layer, and a working layer. The corrosion-resistant furnace shell is resistant to acid radical corrosion. The acid-resistant heat insulation layer is used for heat insulation and to prevent contact between corrosive gases and the corrosion-resistant furnace shell. The fiber buffer layer is used to absorb the expansion displacement of the working layer. The corrosion-resistant furnace shell is formed by connecting several composite plates through a cladding welding method. Each composite plate includes an outer layer of Q355C steel plate and an inner layer of 904L austenitic stainless steel plate. The Q355C steel plate and the 904L austenitic stainless steel plate are composited using an explosive bonding method. The acid-resistant heat insulation layer includes, from the outside to the inside, an anti-intergranular corrosion coating layer, an acid-resistant sprayed protective layer, and a heat insulation layer. The anti-intergranular corrosion coating layer is applied to the inner wall of the corrosion-resistant furnace shell. The acid-resistant sprayed protective layer abuts against the anti-intergranular corrosion coating layer and is connected to the corrosion-resistant furnace shell by anchoring hooks.

2. The hot blast stove using blast furnace gas as energy as claimed in claim 1, characterized in that, The thickness of the 904L austenitic stainless steel plate is 3-4 mm.

3. The hot blast stove using blast furnace gas as energy as claimed in claim 1, characterized in that, The insulation layer comprises two masonry layers with staggered brick joints. The horizontal brick joints of the outer masonry layer are staggered from the horizontal welds of the composite board. The outer masonry layer abuts against the acid-resistant sprayed protective layer.

4. The hot blast stove using blast furnace gas as energy as claimed in claim 1, characterized in that, The fiber buffer layer has a thickness of 120-160 mm and a thermal conductivity of 0.15 W / (1 m·600 °C); the fiber buffer layer can be compressed to 20% of its initial volume.

5. The hot blast stove using blast furnace gas as energy as claimed in claim 1, characterized in that, The working layer includes an inner masonry layer. Each layer of the inner masonry layer along the height direction is composed of several bricks connected along the circumference in a manner where grooves and protrusions cooperate. The arched area of ​​the inner masonry layer is catenary-shaped. Each layer of the inner masonry layer along the height direction is provided with several furnace expansion joints, and each furnace expansion joint is filled with combustible material. Each layer of the inner masonry layer along the height direction is also provided with several furnace body expansion joints. The furnace body expansion joints are parallel and equal-width joints in the vertical section with uniform cross-section, and equal-width joints with grooves and protrusions cooperate in the dome section with variable cross-section.

6. The hot blast stove using blast furnace gas as energy according to claim 5, characterized in that, The working layer also includes an inner heat insulation layer, which is disposed between the inner masonry and the fiber buffer layer. The inner heat insulation layer includes several layers of masonry arranged sequentially from the outside to the inside. Each layer of masonry is uniformly provided with several longitudinal expansion joints along the circumferential direction. The furnace expansion joint accounts for more than 60% of the sum of the furnace expansion joint and the furnace body expansion joint.

7. The hot blast stove using blast furnace gas as energy according to claim 1, characterized in that, The hot air furnace also includes a hot air pipe, and vector expansion joints are provided at the variable cross-section and / or variable angle of the working layer of the hot air pipe. The vector expansion joint is formed by connecting axial expansion joints and radial expansion joints, and a fiber blanket is provided at each vector expansion joint. The width of the vector expansion joint is 8-12 mm, and the thermal conductivity of the fiber blanket is 0.21 W / (1m·600℃). A pipe expansion joint cover brick is provided on the outside of each vector expansion joint.

8. The hot blast stove using blast furnace gas as energy according to claim 1, characterized in that, An axial expansion joint is provided at the hot air outlet of the furnace body. The axial expansion joint is used to accommodate the expansion of the inner lining at the hot air outlet along the axis of the hot air outlet. The axial expansion joint is filled with fiber felt. Several radial expansion joints are also provided at each layer at the hot air outlet of the furnace body along the axis of the hot air outlet. Each radial expansion joint is filled with fiber felt and each radial expansion joint is in the form of a concave-convex fit.

9. The hot blast stove using blast furnace gas as energy according to claim 1, characterized in that, The furnace body is equipped with stress monitoring points and temperature monitoring points on its exterior.

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