Double-layer heat-insulated catalytic box structure for tail gas denitration

Abstract

The utility model discloses a double -deck heat insulation catalytic box structure is used to tail gas denitration, including the outer layer box, still including fixedly connected in the intake pipe of outer layer box one side, the installation frame of removable type installation through bolt in the other side of outer layer box, the exhaust pipe of fixedly connected in the installation frame one end, the plug -in frame of fixedly connected in the other end of installation frame, the first sealing pad of fixedly connected in the corresponding plug -in frame position of outer layer box. Through the corresponding setting of intake pipe and exhaust pipe, can guarantee that tail gas smoothly enters the inner layer box of outer layer box inside and is discharged after completing purification high efficiency, avoid the tail gas to stay in the box, through the heat insulation ceramic fiber cotton filled between outer layer box and inner layer box, can high -efficiently isolate the heat of inner layer box generation, the surface temperature of outer layer box is reduced significantly, reduces the high -temperature baking of surrounding rubber / plastic parts, delays its aging speed, avoids the baking, failure even the risk of fire, promotes system operation safety.

Description

Technical Field

[0001] This utility model relates to the field of exhaust gas denitrification technology, specifically to a double-layer heat-insulated catalytic converter structure for exhaust gas denitrification. Background Technology

[0002] With the increasing number of cars and rising environmental protection requirements, the treatment of vehicle exhaust is becoming increasingly important. The catalytic converter is a major component of vehicle exhaust purification devices. It can convert harmful gases such as carbon monoxide, hydrocarbons, and nitrogen oxides emitted from vehicle exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions, thus purifying the exhaust. The catalyst in the catalytic converter must react at a minimum temperature of 250°C. When the temperature is too low, the conversion efficiency drops sharply. The optimal operating temperature for the catalyst is around 400°C to 800°C. Excessive temperature will also accelerate catalyst aging.

[0003] In existing technologies, catalytic converter enclosures are often protected by single-layer heat shields in practical applications. However, their heat insulation capabilities are significantly limited: when the exhaust temperature inside the catalytic converter enclosure reaches 850°C, the surface temperature of the enclosure itself will rise to 450°C-500°C. Even with the existing single-layer heat shield, the outer surface temperature of the heat shield will still remain around 250°C. This temperature exceeds the tolerance range of most rubber or plastic parts, causing accelerated aging of rubber / plastic components around the enclosure (such as seals for connecting pipes, cable protection sleeves, and plastic shells of adjacent equipment), and even melting and deformation. This not only causes these components to fail, but in severe cases, the high temperature may ignite the plastic components, posing a great threat to the operational safety of the entire denitrification system. Utility Model Content

[0004] The purpose of this utility model is to provide a double-layer heat-insulated catalytic converter structure for exhaust gas denitrification, in order to solve the problem mentioned in the background art that the catalytic converter is usually used for heat protection by a single-layer heat insulation cover in actual application, but the heat insulation capacity is limited. Even if a single-layer heat insulation cover is installed, its outer surface temperature is still about 250°C, which causes such components around the converter to age, melt and deform, which not only causes functional failure, but also, in severe cases, can ignite the components, bringing great safety hazards to the operation of the denitrification system.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a double-layer heat-insulated catalytic converter structure for exhaust gas denitrification, comprising an outer casing, an inlet pipe fixedly connected to one side of the outer casing, a mounting frame detachably mounted to the other side of the outer casing by bolts, an outlet pipe fixedly connected to one end of the mounting frame, an insert frame fixedly connected to the other end of the mounting frame, a first sealing gasket fixedly connected to the corresponding insert frame position on the outer casing, a flexible component installed inside the outer casing, an inner casing installed inside the outer casing by the flexible component, an elastic unit installed on the flexible component, and a filling material between the outer casing and the inner casing. The inner and outer chambers consist of insulating ceramic fiber cotton between the chambers, a detachable catalytic converter mounted on the inner chamber, a fixed honeycomb panel fixed to the inner wall of the inner chamber, a platinum honeycomb panel fixed to the side of the fixed honeycomb panel away from the catalytic converter, a palladium honeycomb panel fixed to the side of the platinum honeycomb panel away from the fixed honeycomb panel, and a rhodium honeycomb panel fixed to the side of the palladium honeycomb panel away from the platinum honeycomb panel. The frame is detachably mounted on the outer chamber. The insulating ceramic fiber cotton is used to isolate the heat generated by the inner chamber. The flexible components are used to prevent the inner chamber from being compressed due to thermal expansion. The catalytic converter is used to purify the exhaust gas.

[0006] Based on the preferred embodiment of this technical solution, the outer casing has a slot at the corresponding position of the insertion frame, the first sealing gasket is fixedly connected to the inner wall of the slot of the outer casing, and the insertion frame is detachably installed in the slot of the outer casing.

[0007] Based on the preferred embodiment of this technical solution, the flexible component includes a first fixed frame fixedly connected at one end to the inner wall of the outer casing, a sliding frame slidably connected to the first fixed frame, a protective plate slidably connected to the outer casing, a second sealing gasket fixedly connected to the outer casing at a position corresponding to the protective plate, a second fixed frame fixedly connected to both ends of the inner casing, an extension frame slidably connected to the second fixed frame, a third sealing gasket fixedly connected to the second fixed frame at a position corresponding to the extension frame, and a fourth sealing gasket fixedly connected to the outside of the extension frame. The inner casing is fixedly connected to the inner side of the sliding frame and the inner side of the protective plate. The fourth sealing gasket is in contact with the outer casing and the mounting frame. The elastic unit provides elasticity to the sliding frame and the extension frame, and the extension frame guides the exhaust gas entering the inner casing, allowing it to enter the inner casing.

[0008] According to the preferred embodiment of this technical solution, the elastic unit includes a first spring fixedly connected between the sliding frame and the outer housing, and a second spring fixedly connected between the extension frame and the second fixed frame. The first spring is used to provide elasticity to the sliding frame, and the second spring is used to provide elasticity to the extension frame.

[0009] Based on the preferred embodiment of this technical solution, four sets of the first fixed frame, sliding frame, first spring, protective plate and second sealing gasket are provided. The four sets of the first fixed frame, sliding frame, first spring, protective plate and second sealing gasket are symmetrically distributed in a ring between the outer box and the inner box.

[0010] Based on the preferred embodiment of this technical solution, two sets of the second fixing frame, the third sealing gasket, the extension frame, the second spring, and the fourth sealing gasket are provided, and the two sets of the second fixing frame, the third sealing gasket, the extension frame, the second spring, and the fourth sealing gasket are symmetrically distributed at both ends of the inner box.

[0011] Based on the preferred embodiment of this technical solution, the catalyst assembly includes an alignment groove formed on the inner wall of the inner chamber, a catalyst block detachably installed inside the inner chamber, a shaped limiting strip fixedly connected to the outside of the catalyst block, and a pressure frame detachably installed on one side of the inner chamber by bolts. The shaped limiting strip is located at the alignment groove, the pressure frame is used to install or remove the catalyst block, and the alignment groove is used to limit the shaped limiting strip so that when it reaches the end, the pressure frame presses down on the shaped limiting strip.

[0012] In the preferred embodiment of this technical solution, four sets of alignment grooves and irregularly shaped limiting strips are provided, and the four sets of alignment grooves and irregularly shaped limiting strips are symmetrically distributed in a ring on the inner wall of the inner layer box and the outer side of the catalyst block. Compared with the prior art, the beneficial effects of this utility model are: 1. By matching the intake and exhaust pipes, the exhaust gas can be smoothly introduced into the inner chamber of the outer chamber and purified before being efficiently discharged, preventing exhaust gas from stagnating inside the chamber. The heat-insulating ceramic fiber cotton filling the space between the outer and inner chambers effectively isolates the heat generated by the inner chamber, significantly reducing the surface temperature of the outer chamber, reducing high-temperature baking of surrounding rubber / plastic components, slowing down their aging, avoiding the risk of melting, failure, or even fire, and improving the safety of system operation.

[0013] 2. The design of flexible components and elastic units can fully offset the thermal expansion of the inner box caused by high temperature, avoid the inner box from being squeezed and causing dents and cracks, and protect the heat insulation ceramic fiber cotton in the interlayer from being squeezed and broken, thus maintaining long-term heat insulation stability.

[0014] 3. By setting alignment grooves on the inner wall of the inner chamber and using irregularly shaped limiting strips on the outside of the catalyst block, installation is simple: just align the irregularly shaped limiting strips with the alignment grooves and insert them, using the length of the alignment grooves to limit the movement, eliminating the need for repeated adjustments and greatly improving installation efficiency. Furthermore, the bolt-removable pressure frame presses and fixes the irregularly shaped limiting strips after the catalyst block is installed in place, preventing the catalyst block from shifting due to exhaust gas impact. When replacing, simply remove the pressure frame to pull the catalyst block out along the alignment grooves, avoiding scratching the inner wall of the inner chamber and effectively reducing the risk of maintenance damage. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of one embodiment of the double-layer heat-insulated catalytic converter structure for exhaust gas denitrification of this utility model; Figure 2 This is a schematic diagram of the thermal insulation ceramic fiber cotton structure of this utility model; Figure 3 This is a schematic diagram of the flexible component and elastic unit structure of this utility model; Figure 4 This is a schematic diagram of the flexible component and elastic unit structure of this utility model; Figure 5 This is a schematic diagram of the catalytic component structure of this utility model.

[0016] Figure 6 This is a cross-sectional structural diagram of the inner box and catalyst block of this utility model.

[0017] In the diagram: 1. Outer housing; 21. Inlet pipe; 22. Mounting frame; 23. Outlet pipe; 24. Insert frame; 25. First sealing gasket; 26. Thermal insulation ceramic fiber cotton; 27. Inner housing; 28. Fixed honeycomb panel; 29. ​​Platinum honeycomb panel; 210. Palladium honeycomb panel; 211. Rhodium honeycomb panel; 31. First fixed frame; 32. Sliding frame; 33. First spring; 34. Protective plate; 35. Second sealing gasket; 36. Second fixed frame; 37. Third sealing gasket; 38. Extension frame; 39. Second spring; 310. Fourth sealing gasket; 41. Alignment groove; 42. Irregularly shaped limiting strip; 43. Catalyst block; 44. Pressure frame. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figure 1-6This utility model provides an embodiment of a double-layer heat-insulating catalytic converter structure for exhaust gas denitrification, including an outer casing 1, an inlet pipe 21 fixedly connected to one side of the outer casing 1, a mounting frame 22 detachably mounted to the other side of the outer casing 1 by bolts, an outlet pipe 23 fixedly connected to one end of the mounting frame 22, an insert frame 24 fixedly connected to the other end of the mounting frame 22, a first sealing gasket 25 fixedly connected to the corresponding position of the insert frame 24 on the outer casing 1, a flexible component installed inside the outer casing 1, an inner casing 27 installed inside the outer casing 1 by the flexible component, an elastic unit installed on the flexible component, heat-insulating ceramic fiber cotton 26 filled between the outer casing 1 and the inner casing 27, a catalytic converter detachably mounted on the inner casing 27, a fixed honeycomb plate 28 fixedly connected to the inner wall of the inner casing 27, a platinum honeycomb plate 29 fixedly connected to the side of the fixed honeycomb plate 28 away from the catalytic converter, and a fixed honeycomb plate 20. The palladium honeycomb plate 210 on the side of plate 29 away from the fixed honeycomb plate 28 and the rhodium honeycomb plate 211 fixedly connected to the side of palladium honeycomb plate 210 away from the platinum honeycomb plate 29 are respectively. The insert frame 24 is detachably installed on the outer box 1. The heat-insulating ceramic fiber cotton 26 is used to isolate the heat generated by the inner box 27. The flexible component is used to prevent the inner box 27 from being squeezed due to thermal expansion. The catalytic component is used to purify the exhaust gas. Through the corresponding setting of the inlet pipe 21 and the outlet pipe 23, the exhaust gas can be smoothly entered into the inner box 27 inside the outer box 1 and discharged efficiently after purification, avoiding the exhaust gas from stagnating in the box. The heat-insulating ceramic fiber cotton 26 filled between the outer box 1 and the inner box 27 can effectively isolate the heat generated by the inner box 27, significantly reduce the surface temperature of the outer box 1, reduce the high temperature baking of the surrounding rubber / plastic parts, slow down their aging speed, avoid the risk of melting, failure or even fire, and improve the safety of system operation.

[0020] Please see Figure 2 A further solution based on this embodiment is as follows: the outer casing 1 has a slot at the corresponding position of the insert frame 24, the first sealing gasket 25 is fixedly connected to the inner wall of the slot of the outer casing 1, and the insert frame 24 is detachably installed in the slot of the outer casing 1. By opening a slot at the position of the insert frame 24 on the outer casing 1, the installation of the insert frame 24 can be accurately positioned, avoiding the offset of the insert frame 24 during installation, and ensuring that the connection position of the insert frame 24 and the outer casing 1 is always consistent. By fixing the first sealing gasket 25 to the inner wall of the slot, when the insert frame 24 is installed in the slot, the first sealing gasket 25 can tightly fit the gap between the outer wall of the insert frame 24 and the inner wall of the slot, effectively blocking the leakage of exhaust gas from the connection part between the insert frame 24 and the outer casing 1, while reducing the heat leakage in the interlayer through the gap, further improving the overall sealing and heat insulation performance.

[0021] Please see Figure 3-4A further embodiment of this solution is as follows: the flexible component includes a first fixed frame 31 fixedly connected at one end to the inner wall of the outer casing 1, a sliding frame 32 slidably connected to the first fixed frame 31, a protective plate 34 slidably connected to the outer casing 1, a second sealing gasket 35 fixedly connected to the outer casing 1 at the position corresponding to the protective plate 34, a second fixed frame 36 fixedly connected to both ends of the inner casing 27, an extension frame 38 slidably connected to the second fixed frame 36, and a third sealing gasket 35 fixedly connected to the second fixed frame 36 at the position corresponding to the extension frame 38. Sealing gasket 37 and fourth sealing gasket 310 are fixedly connected to the outside of extension frame 38. Inner housing 27 is fixedly connected to the inside of sliding frame 32 and the inside of protective plate 34. Fourth sealing gasket 310 is in contact with outer housing 1 and mounting frame 22. Elastic unit is used to provide elasticity to sliding frame 32 and extension frame 38. Extension frame 38 is used to guide exhaust gas entering the interior of outer housing 1 into inner housing 27. Through first fixed frame 31 and sliding frame 38... The sliding fit of the frame 32, combined with the elastic support of the elastic unit, allows the inner box 27 to freely expand and contract along the direction of the sliding frame 32 with thermal expansion, avoiding rigid compression between the inner box 27 and the outer box 1; the cooperation of the protective plate 34 and the second sealing gasket 35 can seal and protect the connection between the sliding frame 32 and the outer box 1, preventing the heat insulation ceramic fiber cotton 26 in the interlayer from leaking out from the sliding gap, while reducing heat loss from the gap; the sliding connection between the second fixed frame 36 and the extension frame 38, combined with the third sealing gasket 3... 7. The extension frame 38 can adapt to the expansion and contraction of the inner box 27 and prevent exhaust gas from entering the interlayer between the outer box 1 and the inner box 27. Through the guiding effect of the extension frame 38, the exhaust gas entering the outer box 1 can be guided to flow precisely to the inner box 27, preventing the exhaust gas from stagnating in the interlayer. Through the fourth sealing gasket 310 contacting the outer box 1 and the mounting frame 22 respectively, the connection gap between the extension frame 38 and the surrounding components can be further sealed, improving the overall sealing performance, so that the exhaust gas is guided to the interior of the inner box 27 as soon as it enters the interior of the outer box 1.

[0022] Please see Figure 3-4A further solution based on this embodiment is as follows: the elastic unit includes a first spring 33 fixedly connected between the sliding frame 32 and the outer housing 1, and a second spring 39 fixedly connected between the extension frame 38 and the second fixed frame 36. The first spring 33 provides elasticity to the sliding frame 32, and the second spring 39 provides elasticity to the extension frame 38. By fixing the first spring 33 between the sliding frame 32 and the outer housing 1, when the inner housing 27 expands thermally and pushes the sliding frame 32 to slide along the first fixed frame 31, the first spring 33 can absorb the displacement stress of the sliding frame 32 through its own elastic deformation, thus preventing the sliding frame 32 from contacting the first fixed frame 36. When the fixed frames 31 are damaged due to rigid collision, and the inner box is cooled and contracted, the first spring 33 can pull the sliding frame 32 to reset, ensuring that the inner box 27 is always in a stable support state. By fixing the second spring 39 between the extension frame 38 and the second fixed frame 36, elastic buffering can be provided for the sliding of the extension frame 38. When the extension frame 38 slides with the inner box 27, the second spring 39 can balance the sliding force of the extension frame 38, prevent excessive friction between the extension frame 38 and the second fixed frame 36, and ensure that the extension frame 38 is always in close contact with the fourth sealing gasket 310 to maintain the flow guiding and sealing effect.

[0023] Please see Figure 2 A further solution based on this embodiment is as follows: four sets of the first fixing frame 31, sliding frame 32, first spring 33, protective plate 34, and second sealing gasket 35 are provided. The four sets of the first fixing frame 31, sliding frame 32, first spring 33, protective plate 34, and second sealing gasket 35 are symmetrically distributed in a ring between the outer box 1 and the inner box 27. By symmetrically distributing the four sets of the first fixing frame 31, sliding frame 32, first spring 33, protective plate 34, and second sealing gasket 35 in a ring, support force can be uniformly provided from all sides of the inner box 27, ensuring that the expansion and contraction of the inner box 27 in all directions during thermal expansion can be uniformly absorbed, avoiding local dents or cracks in the inner box 27 due to uneven stress. At the same time, the symmetrically distributed protective plate 34 and second sealing gasket 35 can fully cover the sliding gap between the outer box 1 and the inner box 27, blocking the heat leakage path from all sides and improving the stability and sealing of the overall structure.

[0024] Please see Figure 2A further solution based on this embodiment is as follows: Two sets of the second fixing frame 36, the third sealing gasket 37, the extension frame 38, the second spring 39, and the fourth sealing gasket 310 are provided. These two sets of the second fixing frame 36, the third sealing gasket 37, the extension frame 38, the second spring 39, and the fourth sealing gasket 310 are symmetrically distributed at both ends of the inner housing 27. By symmetrically distributing these two sets of the second fixing frame 36, the third sealing gasket 37, the extension frame 38, the second spring 39, and the fourth sealing gasket 310 at both ends of the inner housing 27, both ends of the inner housing 27 can receive elastic support and sealing protection, preventing the inner housing 27 from tilting due to unbalanced forces at both ends. Simultaneously, the extension frame 38 at both ends can guide the exhaust gas from both directions of entry and exit, ensuring that the exhaust gas enters and exits the inner housing 27 along a preset path throughout the entire process, reducing turbulent flow of exhaust gas within the housing. Furthermore, the third sealing gasket 37 and the fourth sealing gasket 310 at both ends can form a double seal, further reducing the risk of exhaust gas leakage and heat leakage.

[0025] Please see Figure 5-6 A further embodiment of this solution is as follows: the catalyst assembly includes an alignment groove 41 formed on the inner wall of the inner housing 27, a catalyst block 43 detachably installed inside the inner housing 27, a shaped limiting strip 42 fixedly connected to the outside of the catalyst block 43, and a pressure frame 44 detachably installed on one side of the inner housing 27 by bolts. The shaped limiting strip 42 is located at the alignment groove 41. The pressure frame 44 is used to install or remove the catalyst block 43. The alignment groove 41 is used to limit the shaped limiting strip 42 so that when it reaches its end, the pressure frame 44 presses the shaped limiting strip 42. By forming the alignment groove 41 on the inner wall of the inner housing 27, and cooperating with the shaped limiting strip on the outside of the catalyst block 43, the catalytic effect is achieved. When installing catalyst block 43, simply align the irregularly shaped limiting strip 42 with the alignment groove 41 and insert it to quickly position the catalyst block 43. The length of the alignment groove 41 limits the entry length of the irregularly shaped limiting strip 42, eliminating the need for repeated adjustments and improving installation efficiency. The bolt-removable pressure frame 44 presses and secures the irregularly shaped limiting strip 42 after the catalyst block 43 is in place, preventing displacement of the catalyst block 43 under exhaust gas impact. When replacing the catalyst block 43, simply remove the pressure frame 44 to pull the catalyst block 43 out along the alignment groove 41, avoiding scratching the inner wall of the inner casing 27 during disassembly and reducing the risk of maintenance damage.

[0026] Please see Figure 5A further solution based on this embodiment is as follows: four sets of alignment grooves 41 and irregularly shaped limiting strips 42 are provided. The four sets of alignment grooves 41 and irregularly shaped limiting strips 42 are symmetrically distributed in a ring on the inner wall of the inner box 27 and the outer side of the catalyst block 43. By symmetrically distributing the four sets of alignment grooves 41 and irregularly shaped limiting strips 42 in a ring, the catalyst block 43 can be positioned and fixed from all sides, ensuring that the catalyst block 43 is always in the center of the inner box 27 after installation, and avoiding displacement of the catalyst block 43 due to uneven positioning. At the same time, the ring-shaped symmetrical structure allows there to be no gap between the catalyst block 43 and the inner wall of the inner box 27, preventing exhaust gas from "short-circuiting" through the gap between the catalyst block 43 and the inner wall, ensuring that the exhaust gas can completely pass through the catalyst block 43 for purification, and further improving the denitrification efficiency.

[0027] The materials of the first sealing gasket 25, the second sealing gasket 35, the third sealing gasket 37, and the fourth sealing gasket 310 are all made of flexible graphite composite material. The flexible graphite composite material can fully adapt to the working environment and sealing requirements of the catalytic converter: its temperature resistance range can reach 400-600℃, which completely covers the working temperature of 300-400℃ inside the inner chamber 27. Even if it is in a high-temperature environment for a long time, it will not soften, deform or fail, and can stably maintain the sealing performance.

[0028] Catalyst block 43 is a vanadium-titanium honeycomb catalyst block 43, which is currently the most commonly used type in industrial denitrification (such as diesel vehicle exhaust and coal-fired power plant denitrification). Specifically, it uses titanium dioxide (TiO2) as a carrier, and loads vanadium pentoxide (V2O5), tungsten trioxide (WO3), or molybdenum trioxide (MoO3) as active ingredients. It is molded into a block shape, and the outer side of the block has a pre-reserved mounting groove to match the "irregularly shaped limiting strip 42" (or the irregularly shaped limiting strip 42 and the catalyst block 43 are directly molded together). It has strong adaptability: the working temperature (300-400℃) is completely matched with the high-temperature environment of the inner box 27, and it can efficiently catalyze the reaction of NOx in the exhaust gas with reducing agents (such as ammonia, ammonia from the decomposition of urea) to produce nitrogen and water.

[0029] The thermal insulation ceramic fiber cotton 26 can also adopt other structures in the existing technology, such as high-temperature resistant aerogel felt. Replacing the thermal insulation ceramic fiber cotton 26 with high-temperature resistant aerogel felt has the advantages of higher thermal insulation efficiency. The thermal conductivity of high-temperature resistant aerogel felt is usually as low as 0.018 to 0.025 W / (m·K), which is much lower than that of thermal insulation ceramic fiber cotton 26 (≤0.06 W / (m·K)). Under the same interlayer thickness, it can more effectively block the heat transfer of the inner box 27 to the outside, further reduce the surface temperature of the outer box 1, and reduce the risk of high-temperature baking of the surrounding rubber / plastic parts.

[0030] The fixed honeycomb panel 28, platinum honeycomb panel 29, palladium honeycomb panel 210, and rhodium honeycomb panel 211 can also adopt other structures in the prior art. The fixed honeycomb panel 28, platinum honeycomb panel 29, palladium honeycomb panel 210, and rhodium honeycomb panel 211 can be replaced by an integrated multi-metal coated honeycomb carrier. The advantages of replacing the fixed honeycomb panel 28, platinum honeycomb panel 29, palladium honeycomb panel 210, and rhodium honeycomb panel 211 with an integrated multi-metal coated honeycomb carrier are: the structure is more compact, the integrated design can reduce the gap when splicing the four panels, avoid the exhaust gas from short-circuiting through the gap between the panels, and at the same time reduce the internal installation space occupied by the inner layer box 27. It can adapt to inner layer box 27 of different sizes, and the catalytic efficiency is better. The multi-metal coating (containing platinum, palladium, rhodium and auxiliary catalytic metal) can form a synergistic catalytic effect on the same carrier, covering a wider temperature range (200-500℃). It can improve the initial purification effect of exhaust gas at low temperature and ensure catalytic stability at high temperature.

[0031] Working principle: Exhaust gas first enters the interior of the outer casing 1 through the intake pipe 21 on one side. At this time, the extension frame 38 (with a fourth sealing gasket 310 on the outside that contacts the outer casing 1 and the mounting frame 22, and a second spring 39 connected to the second fixing frame 36) of the inner casing 27, which is slidably supported by the second fixing frame 36 at both ends, will precisely guide the exhaust gas. This, combined with the third sealing gasket 37 of the second fixing frame 36 corresponding to the position of the extension frame 38, prevents exhaust gas from seeping into the gap between the outer casing 1 and the inner casing 27, ensuring that all exhaust gas enters the inner casing 27. It should be noted that... It is clear that the heat inside the inner casing 27 does not accumulate randomly. Through the corresponding arrangement of the intake pipe 21 and the exhaust pipe 23, the exhaust gas smoothly enters the inner casing 27 and is efficiently discharged. The flowing exhaust gas can carry away some of the excess heat from the inner casing 27. Meanwhile, the heat-insulating ceramic fiber cotton 26 filling the space between the outer casing 1 and the inner casing 27 serves to isolate the heat from the inner casing 27 and protect the external rubber / plastic components (such as the first sealing gasket 25, the second sealing gasket 35, the third sealing gasket 37, the fourth sealing gasket 310, etc.), rather than preventing the inner casing 27 from escaping. Internal heat circulation is achieved, and the operating temperature of the inner chamber 27 is maintained within the optimal operating temperature range (400℃-800℃) of the catalyst (catalyst block 43, platinum honeycomb plate 29, palladium honeycomb plate 210, rhodium honeycomb plate 211) through exhaust gas flow. This avoids the problem of accelerated catalyst aging due to excessively high temperatures (above 800℃) in the prior art, and eliminates the conflict of heat accumulation leading to negative high-temperature effects on the catalyst. The exhaust gas entering the inner chamber 27 first passes through the rhodium honeycomb plate 211, palladium honeycomb plate 210, platinum honeycomb plate 29, and fixed honeycomb plate 28 in sequence. After initial purification, the catalyst block 43 is positioned by four sets of annular symmetrical alignment grooves 41 on the inner wall of the inner chamber 27 (with four sets of irregularly shaped limiting strips 42 on the outer side of the catalyst block 43) and fixed by the pressure frame 44 (bolted and detachable, installed on one side of the inner chamber 27) to achieve deep denitrification purification. The catalyst assembly is easily disassembled and assembled by the alignment grooves 41, irregularly shaped limiting strips 42 and detachable pressure frame 44. This design facilitates timely replacement of aged catalyst blocks 43 and ensures that the catalyst is always in an effective working state without sacrificing the catalyst's performance and lifespan.During the purification process, when the inner chamber 27 expands due to high temperature, the four sets of annularly symmetrically distributed first fixed frames 31 and sliding frames 32 (with the inner chamber 27 fixed inside the sliding frames 32) between the outer chamber 1 and the inner chamber 27 will slide along the first fixed frames 31. The first spring 33 between the sliding frame 32 and the outer chamber 1 absorbs the thermal expansion stress through elastic deformation, preventing the inner chamber 27 from being squeezed. At the same time, the second sealing gasket 35 of the outer chamber 1 corresponding to the protective plate 34 cooperates with the protective plate 34 to seal the sliding gap and prevent the heat insulation ceramic fiber cotton 26 in the interlayer from leaking out. The flexible components (first fixed frame 31, sliding frame 32, protective plate 34, second fixed frame 36, extension frame 3) 8) In conjunction with the elastic unit (first spring 33, second spring 39), the thermal expansion of the inner casing 27 due to high temperature can be further offset, preventing damage to the inner casing 27 from compression and affecting the catalyst, thus ensuring stable catalyst operation. Finally, the purified exhaust gas is discharged through the outlet pipe 23 at one end of the mounting frame 22, while the insertion frame 24 at the other end of the mounting frame 22 (bolted detachably to the outer casing 1) (installed in the corresponding slot of the outer casing 1, with a first sealing gasket 25 on the inner wall of the slot) ensures sealing performance during operation and also facilitates subsequent maintenance of the internal components. Throughout the process, efficient exhaust gas purification, casing thermal expansion buffering, and thermal insulation sealing are achieved through the coordinated action of all components.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A double-layer insulated catalytic converter structure for exhaust gas denitrification, comprising an outer casing (1), characterized in that: It also includes an air inlet pipe (21) fixedly connected to one side of the outer casing (1), a mounting frame (22) detachably mounted on the other side of the outer casing (1) by bolts, an air outlet pipe (23) fixedly connected to one end of the mounting frame (22), a plug frame (24) fixedly connected to the other end of the mounting frame (22), a first sealing gasket (25) fixedly connected to the corresponding plug frame (24) position of the outer casing (1), a flexible component installed inside the outer casing (1), an inner casing (27) installed inside the outer casing (1) by the flexible component, an elastic unit installed on the flexible component, thermal insulation ceramic fiber cotton (26) filled between the outer casing (1) and the inner casing (27), and a detachably mounted inner casing. The catalyst assembly on the body (27), the fixed honeycomb plate (28) fixedly connected to the inner wall of the inner box (27), the platinum honeycomb plate (29) fixedly connected to the side of the fixed honeycomb plate (28) away from the catalyst assembly, the palladium honeycomb plate (210) fixedly connected to the side of the platinum honeycomb plate (29) away from the fixed honeycomb plate (28), and the rhodium honeycomb plate (211) fixedly connected to the side of the palladium honeycomb plate (210) away from the platinum honeycomb plate (29). The insert frame (24) is detachably installed on the outer box (1). The heat-insulating ceramic fiber cotton (26) is used to isolate the heat generated by the inner box (27). The flexible component is used to prevent the inner box (27) from being squeezed due to thermal expansion. The catalyst assembly is used to purify the exhaust gas.

2. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 1, characterized in that: The outer casing (1) has a slot at the corresponding position of the insert frame (24), the first sealing gasket (25) is fixedly connected to the inner wall of the slot of the outer casing (1), and the insert frame (24) is detachably installed in the slot of the outer casing (1).

3. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 1, characterized in that: The flexible component includes a first fixed frame (31) fixedly connected at one end to the inner wall of the outer casing (1), a sliding frame (32) slidably connected to the first fixed frame (31), a protective plate (34) slidably connected to the outer casing (1), a second sealing gasket (35) fixedly connected to the outer casing (1) at the position corresponding to the protective plate (34), a second fixed frame (36) fixedly connected to both ends of the inner casing (27), an extension frame (38) slidably connected to the second fixed frame (36), and a third sealing gasket fixedly connected to the second fixed frame (36) at the position corresponding to the extension frame (38). The pad (37) and the fourth sealing pad (310) are fixedly connected to the outside of the extension frame (38). The inner box (27) is fixedly connected to the inside of the sliding frame (32). The inner box (27) is fixedly connected to the inside of the protective plate (34). The fourth sealing pad (310) is in contact with the outer box (1). The fourth sealing pad (310) is in contact with the mounting frame (22). The elastic unit is used to provide elasticity to the sliding frame (32) and the extension frame (38). The extension frame (38) is used to guide the exhaust gas entering the outer box (1) so that it enters the inner box (27).

4. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 3, characterized in that: The elastic unit includes a first spring (33) fixedly connected between the sliding frame (32) and the outer housing (1), and a second spring (39) fixedly connected between the extension frame (38) and the second fixed frame (36). The first spring (33) provides elasticity to the sliding frame (32), and the second spring (39) provides elasticity to the extension frame (38).

5. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 4, characterized in that: The first fixed frame (31), sliding frame (32), first spring (33), protective plate (34) and second sealing gasket (35) are each provided in four sets. The four sets of the first fixed frame (31), sliding frame (32), first spring (33), protective plate (34) and second sealing gasket (35) are symmetrically distributed in a ring between the outer box (1) and the inner box (27).

6. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 4, characterized in that: The second fixing frame (36), the third sealing gasket (37), the extension frame (38), the second spring (39) and the fourth sealing gasket (310) are all provided in two sets. The two sets of the second fixing frame (36), the third sealing gasket (37), the extension frame (38), the second spring (39) and the fourth sealing gasket (310) are symmetrically distributed at both ends of the inner box (27).

7. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 1, characterized in that: The catalyst assembly includes an alignment groove (41) on the inner wall of the inner box (27), a catalyst block (43) that is detachably installed inside the inner box (27), a shaped limiting strip (42) that is fixedly connected to the outside of the catalyst block (43), and a pressure frame (44) that is detachably installed on one side of the inner box (27) by bolts. The shaped limiting strip (42) is located at the alignment groove (41). The pressure frame (44) is used to install or remove the catalyst block (43). The alignment groove (41) is used to limit the shaped limiting strip (42) so that when it enters the end, the pressure frame (44) presses the shaped limiting strip (42).

8. The double-layer heat-insulated catalytic converter structure for exhaust gas denitrification according to claim 1, characterized in that: The alignment groove (41) and the irregular limiting strip (42) are provided in four sets. The four sets of alignment groove (41) and irregular limiting strip (42) are symmetrically distributed in a ring on the inner wall of the inner box (27) and the outer side of the catalyst block (43).

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