Ultrahigh-temperature hydrogen furnace

Abstract

The invention relates to the field of high-temperature hearths, and discloses an ultrahigh-temperature hydrogen furnace which comprises a corundum lining with the aluminum oxide content of 99%, a containing space is formed in the corundum lining and used for containing a heated object, and a plurality of partition plates arranged in a stacked mode are arranged on each outer side face of the corundum lining. The lengths of the partition plates on the same side face are gradually increased from inside to outside, step-shaped lap joint ends are formed at the two ends of each partition plate, and the partition plates on the two adjacent outer side faces of the corundum lining are connected through the lap joint ends. The gap is reserved between the first arched beam and the second arched beam to cope with the expansion stress between the alumina hollow ball bricks and the corundum bricks, so that the first arched beam does not need to bear the weight of the second arched beam and the partition plate, the overall strength of the lining hearth is improved, and the lining hearth is not prone to being damaged.

Description

Technical Field

[0001] The invention relates to the field of high-temperature furnaces, and in particular to an ultra-high-temperature hydrogen furnace. Background Art

[0002] A hydrogen furnace is a heating device that uses hydrogen or a mixture of hydrogen and nitrogen (hydrogen content > 5%) as a protective atmosphere. The furnace used is a three-dimensional space surrounded by a furnace wall for fuel combustion. The internal lining of the existing high-temperature furnace is mostly made of refractory bricks, and the outer wall of the furnace is arranged outside the inner lining. The outer wall of the furnace is generally made of heat-insulating materials and surrounds the inner lining of the high-temperature furnace.

[0003] Because the interior of the high-temperature furnace can usually be heated to over 1000°C during use, the internal lining of the high-temperature furnace will undergo a thermal expansion effect. Under the action of heat transfer, the outer wall of the furnace that is close to the inner lining of the high-temperature furnace will also produce internal stress after being heated. It is understandable that since the inner temperature of the inner lining of the high-temperature furnace is high and the outer temperature is low, the expansion degree of the inner side is greater than that of the outer side. In this case, the inner lining of the high-temperature furnace will expand toward the outer side with a lower temperature, thereby squeezing the outer wall of the furnace. In addition, the outer wall of the furnace is also affected by the internal stress, so the outer wall of the furnace is prone to cracking and damage. Summary of the invention

[0004] The purpose of the present application is to provide an ultra-high temperature hydrogen furnace to solve the problem that the internal lining and the outer wall of the existing high temperature furnace expand due to heat and generate corresponding internal stress. The internal lining of the high temperature furnace will squeeze the outer wall of the furnace during the thermal expansion process. In addition, the outer wall of the furnace is also affected by the internal stress, so the outer wall of the furnace is prone to cracking and damage. The specific technical solution is as follows:

[0005] An ultra-high temperature hydrogen furnace comprises a corundum lining with an alumina content of 99%, wherein a containing space is provided in the corundum lining for placing a heated object, and a plurality of stacked partitions are provided on each outer side of the corundum lining, wherein the lengths of the plurality of partitions on the same side gradually increase from the inside to the outside and step-shaped overlapping ends are formed at both ends of the partitions, and the partitions on two adjacent outer sides of the corundum lining are connected via the overlapping ends.

[0006] As one of the improvements of the above technical solution, the corundum lining includes a first base and a first arch beam, the first base is provided with a groove, a heat source is provided in the groove, the first arch beam is connected to the first base to cover the groove, and the first arch beam and the first base enclose the accommodating space.

[0007] As one of the improvements of the above technical solution, it also includes a second arch beam, which is arranged between the partition and the first arch beam, and there is a gap between the first arch beam and the second arch beam.

[0008] As one of the improvements of the above technical solution, the first base is provided with a first channel, the second arch beam is provided with a second channel connected to the first channel, the second channel is connected to the accommodating space, and the heat source passes through the first channel and the second channel in sequence.

[0009] As one of the improvements of the above technical solution, the heat source includes a silicon-molybdenum rod, and the heat source is arranged close to the inner wall of the groove.

[0010] As one of the improvements of the above technical solution, a raised placement platform is provided at the center of the ground of the groove of the first base.

[0011] As one of the improvements of the above technical solution, first extended ends are provided at both ends of the first arch beam, and second extended ends are provided at both ends of the second arch beam, the first extended end and the second extended end are stacked, there is a gap between the middle section of the first arch beam and the middle section of the second arch beam, and the middle section of the first arch beam or the middle section of the second arch beam is above the groove.

[0012] As one of the improvements of the above technical solution, the partition is made of alumina hollow spherical bricks.

[0013] As one of the improvements of the above technical solution, a buffer layer is provided between the first base and the partition.

[0014] The beneficial effects of the present application are as follows: by leaving a gap between the first arch beam and the second arch beam to cope with the expansion stress between the alumina hollow ball bricks and the corundum bricks, the first arch beam does not have to bear the weight of the second arch beam and the partition, thereby increasing the overall strength of the lining furnace and making it less susceptible to damage; the lengths of several partitions on the same side gradually increase from the inside to the outside and form step-shaped overlapping ends at both ends of the partitions, and the partitions on the two adjacent outer surfaces of the corundum lining are connected by overlapping ends, and the stepped overlapping allows the partitions to have a certain displacement space when heated, reducing thermal stress. In addition, the stacking of partitions may form a multi-layer structure, enhance the thermal insulation effect, reduce heat loss, or improve structural strength, and prevent deformation under high temperature. Secondly, taking the partition at the top as an example, the partitions on both sides can also limit the middle partition.

[0015] Additional aspects and advantages of the present invention will be given in part in the description below, and in part will become apparent from the description below, or will be understood through the practice of the present invention. Of course, it is not necessary to achieve all of the advantages described above at the same time to implement any product or method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Figure 2 It is a schematic structural diagram of the partition of the present invention.

[0019] In the figure: 1. corundum lining; 11. first base; 12. first arch beam; 13. groove; 2. partition; 3. second arch beam; 4. heat source; 5. buffer layer. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 and Figure 2 In an embodiment of the present invention, an ultra-high temperature hydrogen furnace comprises a corundum lining 1 with an alumina content of 99%. The corundum lining 1 is provided with a containing space for placing a heated object. A plurality of stacked partitions 2 are provided on each outer side of the corundum lining 1. The partitions 2 are made of hollow alumina ball bricks. Regarding the selection of materials, corundum has excellent high temperature resistance, excellent chemical stability and good thermal shock resistance. The melting point of corundum is about 2050°C, which enables it to work stably in a high temperature furnace. The hollow alumina ball bricks have good thermal stability and are lightweight. The volume density of the hollow alumina ball bricks is low, which is only 1.11.5g / cm 3 Compared with ordinary heavy bricks (volume density of 2.6-3.0 g / cm 3 ), can significantly reduce the weight of the furnace body, alumina hollow ball bricks have excellent thermal insulation performance, low thermal conductivity, can reduce heat dissipation and improve thermal efficiency;

[0022] Since the furnace outer wall of the existing high-temperature furnace is integrated and surrounded by the internal lining of the high-temperature furnace, and sufficient deformation space is not reserved, the internal temperature of the high-temperature furnace usually continues to rise during use, which causes the internal lining of the high-temperature furnace to have a thermal expansion effect. Under the action of heat transfer, the furnace outer wall close to the internal lining of the high-temperature furnace will also generate internal stress after being heated. The internal lining of the high-temperature furnace will expand toward the outer side with lower temperature, thereby squeezing the furnace outer wall. In addition, the furnace outer wall is also affected by the internal stress at the same time, so the furnace outer wall is easy to crack and be damaged. For this reason, the present invention provides some embodiments For example, the above problems are solved. Specifically, the lengths of several partitions 2 on the same side of (corundum lining 1) gradually increase from the inside to the outside and step-shaped overlap ends are formed at both ends of the partition 2. The partitions 2 on the two adjacent outer sides of the corundum lining 1 are connected by the overlap ends. The step-shaped overlap allows the partition 2 to have a certain displacement space when heated, reducing thermal stress. In addition, the stacking of the partitions 2 may form a multi-layer structure, enhance the heat insulation effect, reduce heat loss, or improve the structural strength, and prevent deformation under high temperature. Secondly, taking the partition 2 at the top as an example, the partitions 2 on both sides can also limit the middle partition 2;

[0023] In an ultra-high temperature environment, the lining is in direct contact with the high temperature area and has the highest temperature, while the partition 2 is located on the outside and has a lower temperature, but it will also be affected by heat conduction and radiation. The main function of the partition 2 is to reduce heat loss to the outside, so its temperature gradient may be large, that is, the temperature on the inside (the side close to the lining) is high and the temperature on the outside is low. The stacking arrangement of multiple partitions 2 can minimize heat loss.

[0024] The corundum lining 1 includes a first base 11 and a first arch beam 12. The first base 11 is provided with a groove 13. A heat source 4 is provided in the groove 13. The first arch beam 12 is connected to the first base 11 to cover the groove 13. The first arch beam 12 and the first base 11 enclose a receiving space. The second arch beam 3 is arranged between the partition 2 and the first arch beam 12. There is a gap between the first arch beam 12 and the second arch beam 3. The second arch beam 3 is also made of alumina hollow spherical bricks. Since the outer side of the first arch beam 12 also needs to be provided with a corresponding partition 2 to play a role of heat preservation and heat insulation, it is necessary to configure a corresponding second arch beam 3. However, if the second arch beam 3 and the partition 2 are directly connected, the heat source 4 is provided. When the partition 2 formed by alumina hollow ball bricks is directly stacked on the first arch beam 12, due to the greater brittleness of corundum, it may cause cracks or damage during mechanical impact or improper operation. In this embodiment, the first arch beam 12 is more easily damaged when bearing weight. For this reason, the purpose of leaving a gap between the first arch beam 12 and the second arch beam 3 is to prevent the first arch beam 12 from bearing the weight of the second arch beam 3 and the top cover. Secondly, the above-mentioned buffer zone is formed to cope with the expansion stress between the alumina hollow ball bricks and the corundum bricks when the interior of the first base 11 is heated to 1000°C to 1800°C, thereby avoiding cracks or falling off of the alumina hollow ball bricks and the corundum bricks.

[0025] In fact, the alumina content of the corundum lining 1 of the existing hydrogen furnace is usually 95%, achieving the best balance between high-temperature stability, thermal shock resistance, mechanical strength and cost. The right amount of additives can improve the flexural strength and impact resistance of the material through dispersion strengthening or phase change toughening mechanism, thereby extending the service life of the lining. This is also the reason why the outer wall of the furnace can be directly set on the corundum lining 1 (with an alumina content of 95%), because the corundum lining 1 has sufficient mechanical strength to support the outer wall of the furnace (especially the top of the corundum lining 1 also needs to bear part of the weight of the outer wall of the furnace). Once the alumina content of the corundum lining 1 is increased to 99%, the mechanical strength, flexural strength and impact resistance of the corundum lining 1 will decrease. Therefore, the present invention leaves a gap between the first arch beam 12 and the second arch beam 3.

[0026] Preferably, the first arch beam 12 is provided with a first extended end at both ends, and the second arch beam 3 is provided with a second extended end at both ends, the first extended end and the second extended end are stacked, there is a gap between the middle section of the first arch beam 12 and the middle section of the second arch beam 3, and the middle section of the first arch beam 12 or the middle section of the second arch beam 3 is above the groove 13, and the supporting capacity of the second arch beam 3 can be improved by setting the first extended end and the second extended end.

[0027] In addition, the present invention is also designed with a channel for installing the heat source 4. Specifically, the first base 11 is provided with a first channel, the second arch beam 3 is provided with a second channel connected to the first channel, the second channel is connected to the accommodating space, and the heat source 4 passes through the first channel and the second channel in sequence. Preferably, the heat source 4 includes a silicon-molybdenum rod, which is mainly used for high-temperature heating elements. It is synthesized from silicon and molybdenum elements, can provide a stable heating effect and has good oxidation resistance and corrosion resistance. The heat source 4 passes through the first channel and the second channel in sequence. The heat source 4 is arranged close to the inner wall of the groove 13, and a raised placement platform is provided at the center of the ground of the groove 13 of the first base 11.

[0028] In the present invention, the lengths of several partitions 2 gradually increase from the inside to the outside, and the partitions 2 are made of alumina hollow ball bricks. Regarding alumina hollow ball bricks, due to their low thermal shock resistance, rapid temperature changes (such as a sharp increase or decrease in temperature) may cause the brick body to crack or fall off. This is because the expansion coefficients of the air layer inside the hollow ball brick are different from those of the external material, resulting in stress concentration. In this embodiment, when alumina hollow ball bricks of various sizes are stacked together, their overall thermal conductivity will be the composite effect of multiple thermal conductivities. Smaller bricks may allow heat to pass faster through faster heat transfer, while larger bricks will provide better insulation by reducing heat conduction in the heat flow path. The above design can minimize the impact of thermal shock on alumina hollow ball bricks.

[0029] In some embodiments, a buffer layer 5 is provided between the first base 11 and the partition 2. The reason for using a high-temperature ceramic fiber mat as the buffer layer 5 is that the high-temperature ceramic fiber mat (such as an aluminum silicate fiber mat, a ceramic fiber cloth) has excellent thermal insulation and thermal expansion properties, and can effectively alleviate the stress caused by temperature changes; in addition to considering its material, thickness and thermal isolation capacity, the design of the structural shape also has a crucial impact on its performance, adaptability and service life, and a ceramic fiber mat of a single thickness may be difficult to balance the requirements of thermal insulation and mechanical strength in some cases. In this regard, the present invention further optimizes the structural shape of the high-temperature ceramic fiber mat, and the specific structure is as follows:

[0030] The high-temperature ceramic fiber mat includes a high-density fiber layer and a low-density fiber layer stacked together. The high-density fiber layer is arranged close to the first base 11, and the low-density fiber layer is arranged close to the partition 2. The thermal insulation performance and flexibility of the high-temperature ceramic fiber mat are optimized by designing a multi-layer structure. The inner high-density fiber layer can more effectively prevent heat conduction, while the outer low-density fiber layer increases flexibility and buffering capacity.

[0031] Considering that the interior of the first base 11 of the present invention needs to be heated to 1000° C. to 1800° C., in this scenario, the thermal expansion coefficient of corundum is generally low (approximately 6×10 -6 / ℃), which means that compared with high-temperature ceramic fiber mats (larger thermal expansion), corundum has smaller differences in thermal expansion, smaller thermal stress, and is less prone to expansion deformation. Therefore, when designing the buffer layer 5, the expansion difference of corundum has less impact on the structure; while alumina hollow ball bricks have good thermal insulation and light weight, but their thermal expansion coefficient is usually larger than that of corundum (about 8×10 -6 / ℃), therefore, the difference in thermal expansion of the external alumina hollow sphere bricks may cause more thermal stress at high temperatures;

[0032] In the furnace structure, alumina hollow ball bricks are usually used to provide thermal isolation and reduce weight, so the cooperation between its thermal insulation effect and the ceramic fiber mat is very important. In this regard, the present invention also provides an embodiment to solve the above problem. The ratio of the thickness of the high-density fiber layer to the thickness of the low-density fiber layer is 1:3-5. Since the thermal expansion of the corundum brick is small, the low-density fiber layer can be appropriately thickened. The function of the high-density ceramic fiber layer is to provide mechanical support, especially between the alumina hollow ball bricks and the low-density ceramic fiber layer;

[0033] Preferably, the thickness of the thick high-density fiber layer is 10-20 mm, ensuring that it can provide sufficient mechanical strength without hindering the thermal insulation effect, while the thickness of the low-density fiber layer is 30-100 mm, which can provide effective thermal isolation while avoiding excessive pressure on the alumina hollow ball bricks and the corundum lining 1 due to excessive temperature.

[0034] The following is an analysis of the effect of different thickness ratios between the high-density fiber layer and the low-density fiber layer:

[0035] 1. The thickness of the high-density fiber layer is 10mm, and the thickness of the low-density fiber layer is 30mm (ratio 1:3);

[0036] Thermal insulation effect: The high-density fiber layer is thinner, mainly to improve the overall structural strength and thermal stability, while the low-density fiber layer is thicker, which helps to provide better thermal insulation effect;

[0037] Compressive strength: Due to the small thickness of the high-density fiber layer, its compressive strength may be insufficient, and it needs to rely on the density and structural characteristics of the low-density fiber layer to withstand external pressure.

[0038] Heat resistance: The high-density fiber layer can still withstand higher temperatures, but the low-density fiber layer is thinner, which may lead to poor insulation effect and is suitable for applications with less high temperature requirements (such as 1200℃ to 1500℃ range).

[0039] 2. The thickness of the high-density fiber layer is 15mm, and the thickness of the low-density fiber layer is 45mm (ratio 1:3);

[0040] Thermal insulation effect: The overall thermal insulation effect is good, especially at high temperatures. The thickening of the low-density fiber layer effectively enhances the thermal resistance. The high-density fiber layer has a moderate thickness, which helps to improve the overall high-temperature resistance.

[0041] Compressive strength: The combination of high-density fiber layer and low-density fiber layer can better balance thermal isolation and strength, and is suitable for common high-temperature environments.

[0042] Heat resistance: Suitable for application scenarios with temperatures around 1500°C. Such a combination should be able to provide good thermal isolation and mechanical stability.

[0043] 3. The thickness of the high-density fiber layer is 20mm, and the thickness of the low-density fiber layer is 60mm (ratio 1:3);

[0044] Thermal insulation effect: The low-density fiber layer is significantly thickened, which can effectively improve the thermal insulation effect, especially in applications with temperatures of 1600°C and above.

[0045] Compressive strength: The high-density fiber layer provides sufficient compressive strength and is suitable for applications that need to withstand a certain amount of pressure. The low-density fiber layer provides sufficient thermal protection and reduces heat conduction.

[0046] Heat resistance: This combination is suitable for environments with temperatures of 1500℃ to 1800℃ or higher. The high-density fiber layer provides additional thermal stability to the structure, and the low-density fiber layer provides excellent thermal insulation.

[0047] 4. The thickness of the high-density fiber layer is 10mm, and the thickness of the low-density fiber layer is 50mm (ratio 1:5);

[0048] Thermal insulation effect: In this setting, the thickness of the low-density fiber layer is large, which can provide very good thermal insulation and is suitable for higher temperature applications (for example, 1600°C to 1800°C).

[0049] Compressive strength: Since the high-density fiber layer is thinner and the overall compressive strength is relatively low, the low-density fiber layer provides limited mechanical support. Careful selection of applicable occasions is required to avoid structural instability due to high external pressure.

[0050] Heat resistance: Suitable for harsh high temperature environments, especially when high thermal insulation requirements are required, and suitable for applications that require better thermal protection.

[0051] 5. The thickness of the high-density fiber layer is 20mm, and the thickness of the low-density fiber layer is 100mm (ratio 1:5);

[0052] Thermal insulation effect: The thickness of the low-density fiber layer is greatly increased, which can greatly improve the thermal insulation effect. It is suitable for high-temperature and long-term operation environments. It has a better effect for applications that require long-term exposure to 1800℃ or higher temperatures.

[0053] Compressive strength: The high-density fiber layer provides better strength support, while the low-density fiber layer provides excellent thermal protection. It is necessary to ensure that the low-density fiber layer is stable enough to avoid mechanical stability problems caused by excessive thickness.

[0054] Heat resistance: Suitable for extreme high temperature applications, such as environments above 1800°C, and can maintain very good thermal insulation and high temperature resistance.

[0055] Therefore, the ratio of the thickness of the high-density fiber layer to the thickness of the low-density fiber layer of 1:3 (high density: low density) is suitable for general high-temperature applications in the range of 1200°C to 1600°C, providing better balanced performance; the ratio of the thickness of the high-density fiber layer to the thickness of the low-density fiber layer of 1:4 to 1:5 (high density: low density) is suitable for higher temperature applications (1600°C to 1800°C or higher). The thickening of the low-density fiber layer can effectively enhance the thermal insulation, but the high-density fiber layer should ensure sufficient compressive strength. A larger low-density fiber layer thickness helps to improve thermal resistance, but may affect compressive strength. The combination ratio needs to be adjusted according to the actual use environment.

[0056] In some embodiments, the high-temperature ceramic fiber mat is a honeycomb structure. By designing the ceramic fiber mat into a honeycomb structure, its thermal insulation can be greatly improved, while its strength and bearing capacity can be enhanced. The honeycomb structure can increase the specific surface area of ​​the material and increase the number of air barriers, thereby enhancing the thermal resistance performance. The hollow part of the honeycomb structure helps to reduce the conduction of heat and improve the thermal insulation effect.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. An ultra-high temperature hydrogen furnace, characterized in that: It comprises a corundum lining with an alumina content of 99%, wherein the corundum lining is provided with a containing space for placing a heated object, and each outer side of the corundum lining is provided with a plurality of stacked partitions, the lengths of the plurality of partitions on the same side gradually increase from the inside to the outside and form stepped overlapping ends at both ends of the partitions, and the partitions on two adjacent outer sides of the corundum lining are connected via the overlapping ends.

2. The ultra-high temperature hydrogen furnace according to claim 1, characterized in that: The corundum lining includes a first base and a first arch beam. The first base is provided with a groove. A heat source is provided in the groove. The first arch beam is connected to the first base to cover the groove. The first arch beam and the first base enclose the accommodating space.

3. The ultra-high temperature hydrogen furnace according to claim 2, characterized in that: The invention also includes a second arch beam, which is arranged between the partition and the first arch beam, and there is a gap between the first arch beam and the second arch beam.

4. The ultra-high temperature hydrogen furnace according to claim 3, characterized in that: The first base is provided with a first channel, the second arch beam is provided with a second channel connected to the first channel, the second channel is communicated with the accommodating space, and the heat source passes through the first channel and the second channel in sequence.

5. The ultra-high temperature hydrogen furnace according to claim 4, characterized in that: The heat source comprises a silicon-molybdenum rod, and the heat source is arranged close to the inner wall of the groove.

6. The ultra-high temperature hydrogen furnace according to claim 5, characterized in that: A raised placement platform is provided at the center of the bottom surface of the groove of the first base.

7. The ultra-high temperature hydrogen furnace according to claim 6, characterized in that: The first arch beam has first extended ends at both ends, and the second arch beam has second extended ends at both ends. The first extended ends and the second extended ends are stacked. There is a gap between the middle section of the first arch beam and the middle section of the second arch beam, and the middle section of the first arch beam or the middle section of the second arch beam is above the groove.

8. The ultra-high temperature hydrogen furnace according to claim 7, characterized in that: The partition is made of alumina hollow ball bricks.

9. The ultra-high temperature hydrogen furnace according to claim 8, characterized in that: A buffer layer is provided between the first base and the partition.

Images