A heat insulation structure for the furnace chamber of a formaldehyde production exhaust gas incinerator

Abstract

This utility model discloses a heat insulation structure for the furnace chamber of a formaldehyde production tail gas incinerator, relating to the field of incinerator technology. It includes a steel shell with a cooling section at the upper part. A diatomaceous earth layer is bonded to the inner wall of the steel shell using a binder. This utility model utilizes a combination of the diatomaceous earth layer, a casting layer, and a ceramic fiber layer to increase heat transfer resistance and improve heat insulation. Simultaneously, the corrosion-resistant, thermally shock-resistant, and acid-resistant ceramic fiber layer is placed on the inner side, with higher porosity and better insulation effect, while the less heat-resistant diatomaceous earth is placed on the outermost layer. The diatomaceous earth layer and ceramic fiber layer are connected by a high-alumina casting material with good bonding properties and slightly lower temperature and thermal shock resistance. This not only achieves efficient heat insulation but also significantly reduces construction costs, extends service life, and enhances practicality. A fixing mechanism allows for quick connection between the fixing seat and the pin, facilitating the fixing of the ceramic fiber layer, improving the fixing effect, and making it more stable.

Description

Technical Field

[0001] This utility model relates to the field of incinerator technology, specifically a heat insulation structure for the furnace chamber of a formaldehyde production tail gas incinerator. Background Technology

[0002] Formaldehyde is a widely used, simple-to-produce, and readily available chemical product, a major downstream product of methanol. Global annual production is around 25 million tons, with approximately 30% of methanol being used to produce formaldehyde. The combustible gases, such as hydrogen and carbon monoxide, produced as byproducts in formaldehyde production must be burned in a tail gas incinerator. Some formaldehyde undergoes disproportionation and oxidation reactions at high temperatures to produce formic acid, which corrodes the furnace lining.

[0003] Most traditional incinerators typically use heavy clay bricks with poor thermal shock stability as the furnace lining material. However, due to the frequent start-ups and shutdowns caused by the periodic replacement of formaldehyde catalysts, the furnace is constantly subjected to rapid high and low temperature changes. This is extremely unfriendly to the use of refractory materials inside the furnace, leading to cracking of traditional clay bricks due to thermal shock, reducing their service life, and requiring professional repair. In addition, some manufacturers use ceramic fiber felt with better thermal shock resistance as the main thermal insulation material. Although it has achieved some results, the cost has increased significantly. Moreover, ceramic fiber is not as good as porous lightweight refractory materials such as diatomaceous earth and lightweight clay bricks in terms of thermal insulation. Therefore, a thermal insulation structure for the furnace of a formaldehyde production tail gas incinerator is needed to solve the above problems. Utility Model Content

[0004] The purpose of this invention is to provide a heat insulation structure for the furnace chamber of a formaldehyde production tail gas incinerator, so as to solve the problems mentioned in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a heat insulation structure for the furnace chamber of a formaldehyde production tail gas incinerator, comprising a steel shell, a cooling section in the upper part of the steel shell, a diatomaceous earth layer bonded to the inner wall of the steel shell by a binder, a casting layer bonded to one side of the diatomaceous earth layer, a ceramic fiber layer connected to one side of the casting layer by several fasteners, and one end of the fasteners being welded to the inner wall of the steel shell, a number of fixing mechanisms being provided between the casting layer and the ceramic fiber layer, a lightweight clay layer being provided at the bottom of the steel shell, and the lightweight clay layer being located below the diatomaceous earth layer, the casting layer and the ceramic fiber layer, two distributors being provided above the lightweight clay layer, and one end of each of the two distributors extending to the outside of the steel shell, and a fan connected to one end of the upper distributor being provided outside the steel shell.

[0006] Furthermore, the fixing mechanism includes a fixing seat, and several fixing seats are provided. Several installation grooves are opened on the side wall of the casting layer near the ceramic fiber layer. The fixing seat is installed in the installation groove. A pin shaft penetrating the ceramic fiber layer is provided on one side of the fixing seat. A cavity is opened in the fixing seat. One end of the pin shaft extends into the cavity and is connected to a hexagonal block. A docking groove adapted to the combination structure of the hexagonal block and the pin shaft is opened on one side of the inner wall of the cavity. Two sets of sliding rods are symmetrically arranged in the cavity. A fixing block is connected to one end of the sliding rod near the pin shaft. A spring and a slider are sleeved on the outside of the sliding rod on the side of the fixing block. The slider is located on the side near the pin shaft. An insert is provided between each set of two sliders, and the insert is fixedly connected to the slider. A slot adapted to the slider is symmetrically opened on the outer wall of the pin shaft. A pad is sleeved on the outside of one end of the pin shaft on the side of the ceramic fiber layer. The fixing mechanism can quickly and initially position and fix the ceramic fiber layer by docking the fixing seat and the pin shaft while using fasteners to install the ceramic fiber layer, and can improve its fixing effect.

[0007] Furthermore, the fastener includes a support rod and a pad. One end of the support rod is welded to the inner wall of the steel shell, and the other end of the support rod is fitted with a pad on the outside of the ceramic fiber layer. A nut is threaded onto the side of the pad away from the ceramic fiber layer to install and fix the ceramic fiber layer, while also providing support and reinforcement for the diatomaceous earth layer and the casting layer.

[0008] Furthermore, the inner wall of the steel shell is uniformly welded with several pre-welded components, which are located inside the diatomaceous earth layer and the casting layer. The pre-welded components are Y-shaped dendritic structures to improve the structural strength of the casting layer and make it more stable.

[0009] Furthermore, the outer wall of the fixing seat and the inner wall of the mounting groove are respectively provided with several external threads and internal threads. The cross-section of the insert block is a right-angled trapezoidal structure. One end of the fixing seat is provided with a hexagonal groove to facilitate the assembly and disassembly of the fixing seat. The structure of the hexagonal groove makes it easy to disassemble it using a corresponding wrench.

[0010] Furthermore, the diatomaceous earth layer is diatomaceous earth or a mixture of one or more clay-containing diatomaceous earth, the casting layer is aluminosilicate castable or high wear-resistant castable or a mixture thereof, the ceramic fiber layer is preferably a special fiber felt with mullite crystals as the main component, and the binder is calcium aluminate cement, hydrated alumina, silica sol, alumina gel powder or phenolic resin, etc.

[0011] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model uses three layers of insulation material, namely diatomaceous earth, castable, and ceramic fiber, each with its own advantages and disadvantages, to increase the thermal resistance and achieve better thermal insulation effect. At the same time, the ceramic fiber layer, which is corrosion-resistant, has good thermal shock stability, and is acid-resistant, is placed on the inner side, with higher porosity and better thermal insulation effect, while the diatomaceous earth, which is not resistant to high temperature, is placed on the outermost layer. The diatomaceous earth layer and the ceramic fiber layer are connected by a high-alumina castable with good bonding, temperature resistance, and slightly poor thermal shock resistance. This not only achieves a high-efficiency thermal insulation effect, but also significantly reduces the construction cost, has a longer service life, is convenient to use, and is more practical. 2. This utility model, through its fixing mechanism, allows the fixing seat and the pin to be quickly connected, facilitating the fixing of the ceramic fiber layer, improving its fixing effect, and providing support without affecting subsequent disassembly. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a top-section structural diagram of the steel shell, diatomaceous earth layer, ceramic fiber layer and fasteners of this utility model. Figure 3 This is a utility model Figure 1 A magnified structural diagram of A in the middle; Figure 4 This is a schematic diagram of the structure between the fixing seat and the pin of this utility model; Figure 5 This is a schematic diagram of the structure between the insert block, the fixing seat, and the pin of this utility model.

[0013] Numbered in the diagram: 1. Steel shell; 2. Cooling section; 3. Fastener; 4. Pre-welded part; 5. Diatomaceous earth layer; 6. Casting layer; 7. Ceramic fiber layer; 8. Lightweight clay layer; 9. Distributor; 10. Fan; 11. Support rod; 12. Pad one; 13. Fixing seat; 14. Pin; 15. Slide rod; 16. Spring; 17. Slider; 18. Fixing block; 19. Insert block; 20. Hexagonal block; 21. Pad two; 22. Chamber; 23. Connecting groove. Detailed Implementation

[0014] 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.

[0015] Example: Figure 1 - Figure 5As shown, this utility model provides a technical solution: a heat insulation structure for the furnace chamber of a formaldehyde production exhaust gas incinerator, including a steel shell 1, a cooling section 2 in the upper part of the steel shell 1, a diatomaceous earth layer 5 bonded to the inner wall of the steel shell 1 by an adhesive, a casting layer 6 bonded to one side of the diatomaceous earth layer 5, and a ceramic fiber layer 7 connected to one side of the casting layer 6 by a plurality of fasteners 3, with one end of the fasteners 3 welded to the inner wall of the steel shell 1. In this example, the fasteners 3 are preferably made of high-temperature aluminum alloy, and the casting layer 6 and... Several fixing mechanisms are provided between the ceramic fiber layers 7. A lightweight clay layer 8 is provided at the bottom of the steel shell 1. The lightweight clay layer 8 is located below the diatomaceous earth layer 5, the casting layer 6 and the ceramic fiber layer 7. In this example, the thickness of the lightweight clay layer 8 is 15-35 cm to better reduce the heat loss in the furnace. Two distributors 9 are provided above the lightweight clay layer 8, and one end of each distributor 9 extends to the outside of the steel shell 1. A fan 10 is provided outside the steel shell 1 and connected to one end of the upper distributor 9. In this example, the fixing mechanism includes a fixing seat 13, and there are several fixing seats 13. Several mounting grooves are opened on the side wall of the casting layer 6 near the ceramic fiber layer 7. The fixing seats 13 are installed in the mounting grooves. A pin 14 penetrating the ceramic fiber layer 7 is provided on one side of the fixing seat 13. A cavity 22 is opened in the fixing seat 13. One end of the pin 14 extends into the cavity 22 and is connected to a hexagonal block 20. In this example, the end of the pin 14 away from the fixing seat 13 has a hexagonal structure. A mating groove 23 adapted to the combined structure of the hexagonal block 20 and the pin 14 is opened on the inner wall of one side of the cavity 22. Two sets of sliding rods 15 are symmetrically arranged in the cavity 22. The sliding rods 15 are close to the pin. One end of the shaft 14 is connected to a fixing block 18. A spring 16 and a slider 17 are sleeved on the outside of the slider 15 on one side of the fixing block 18. The slider 17 is located on the side close to the shaft 14. An insert 19 is provided between each group of two sliders 17, and the insert 19 is fixedly connected to the slider 17. The outer wall of the shaft 14 is symmetrically provided with slots that are adapted to the sliders 17. A pad 21 is sleeved on the outside of one end of the shaft 14 on one side of the ceramic fiber layer 7. With the setting of the fixing mechanism, while the ceramic fiber layer 7 is installed using the fastener 3, the fixing seat 13 and the shaft 14 can be connected to achieve quick initial positioning and fixing of the ceramic fiber layer 7, and improve its fixing effect. In this example, fastener 3 includes a support rod 11 and a pad 12. One end of the support rod 11 is welded to the inner wall of the steel shell 1, and the other end of the support rod 11 is fitted with the pad 12 on the outside of the ceramic fiber layer 7. A nut is threaded onto the side of the pad 12 away from the ceramic fiber layer 7 to install and fix the ceramic fiber layer 7, while also providing support and reinforcement for the diatomaceous earth layer 5 and the cast layer 6. In this example, several pre-welded parts 4 are evenly distributed and welded to the inner wall of the steel shell 1. The pre-welded parts 4 are located inside the diatomaceous earth layer 5 and the cast layer 6. The pre-welded parts 4 have a Y-shaped dendritic structure to improve the structural strength of the cast layer 6 and make it more stable.

[0016] In this example, the outer wall of the fixing seat 13 and the inner wall of the mounting groove are respectively provided with several external threads and internal threads. The cross section of the insert 19 is a right trapezoidal structure. One end of the fixing seat 13 is provided with a hexagonal groove to facilitate the assembly and disassembly of the fixing seat 13. The structure of the hexagonal groove makes it easy to disassemble it using a corresponding wrench. Furthermore, the diatomaceous earth layer 5 is diatomaceous earth or a mixture of one or more clay-containing diatomaceous earth, the casting layer 6 is aluminosilicate castable or high wear-resistant castable or a mixture thereof, and the ceramic fiber layer 7 is preferably a specially made fiber felt with mullite crystals as the main component to cope with the most severe combustion chamber environment. The binder is calcium aluminate cement, hydrated alumina, silica sol, alumina gel powder or phenolic resin, etc. In this example, the diatomaceous earth layer 5 is preferably used at a temperature of 100-500℃ and a masonry thickness of 10-15 cm, the casting layer 6 is used at a temperature of 400-800℃ and a casting thickness of 10-15 cm, and the ceramic fiber layer 7 is preferably 5-15 cm thick and used at a temperature of 1100-1600℃. The total thickness of the diatomaceous earth layer 5 and the casting layer 6 just covers the pre-welded part 4. In this example, the diatomaceous earth layer 5 is made by mixing powdered diatomaceous earth with a suitable binder and stirring it evenly. This mixture is then evenly applied to the inner surface of the cleaned and polished steel shell 1. After air drying, the diatomaceous earth layer 5 is heated to 110°C in the furnace and held for 4-8 hours to ensure that the moisture in the diatomaceous earth is completely evaporated and that the binder has completed its initial hardening, thus giving the entire diatomaceous earth layer 5 sufficient mechanical strength. The casting layer 6 is made by mixing powdered casting material with a suitable binder and stirring it evenly. This mixture is then evenly applied to the surface of the diatomaceous earth layer, air dried, and then heated to 110°C and held for 6-24 hours to ensure that the moisture in the casting layer is evaporated and that the binder has completed its initial hardening. After the holding period, the furnace temperature is increased to 300°C and held for 4 hours. Then, the temperature is gradually increased to 800°C at a rate of 2-3°C per minute and held for 48 hours to complete the furnace baking operation, allowing the refractory material to sinter to a crystalline structure and the binder to solidify into a carbon skeleton. Thus, refractory materials have gained higher mechanical strength and a high-temperature resistant crystalline structure.

[0017] The working principle of this invention is as follows: A ceramic fiber felt with mullite as its main crystal structure, exhibiting excellent corrosion resistance and thermal shock stability, serves as the inner lining, enhancing its resistance to formic acid corrosion. A high-alumina castable with good bonding properties, corrosion resistance, and a high softening point is used as the middle layer, further improving thermal shock stability. Inexpensive diatomaceous earth with high porosity is used as the outermost layer, reducing investment costs. Simultaneously, this three-layer fire-resistant insulation scheme increases thermal resistance, reducing heat loss. This insulation structure offers lower costs, better performance, and a longer lifespan. Increased heat recovery enhances its economic value. Replacing bulky clay-shaped refractory bricks, this design simplifies transportation and construction. The fixing mechanism requires pre-installing the fixing seat 13 into the mounting groove, then placing the pad 21 on the outside of the pin 14. After the pin 14 passes through the ceramic fiber layer 7, one end of the pin 14 is inserted into the corresponding fixing seat 13. This causes one end of the pin 14 to press against the inclined surface on one side, pushing the pin 14 to drive the connected slider 17 to slide along the slide rod 15 and compress the spring 16 until the slider 17 moves... As the pin 14 continues to push out of the slot, one end of the hexagonal block 20 is inserted into the mating groove 23. At this time, the slider 17 will be reset under the elastic force of the spring 16, thereby driving the connected insert 19 to reset and insert it into the slot opened on the pin 14. This passively restricts and fixes the pin 14, thereby fixing the ceramic fiber layer 7 to the pin 14 and the pad 21, improving its stability and fixing effect. It also makes it easier to install nuts on the support rod 11 later, making it convenient to use and more practical.

[0018] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A heat insulation structure for the furnace chamber of a formaldehyde production tail gas incinerator, comprising a steel shell (1), wherein a cooling section (2) is provided in the upper part of the steel shell (1), characterized in that: The inner wall of the steel shell (1) is bonded with a diatomaceous earth layer (5) by a binder. A casting layer (6) is bonded to one side of the diatomaceous earth layer (5). A ceramic fiber layer (7) is connected to one side of the casting layer (6) by several fasteners (3). One end of the fasteners (3) is welded to the inner wall of the steel shell (1). Several fixing mechanisms are provided between the casting layer (6) and the ceramic fiber layer (7). A lightweight clay layer (8) is provided at the bottom of the steel shell (1). The lightweight clay layer (8) is located below the diatomaceous earth layer (5), the casting layer (6) and the ceramic fiber layer (7). Two distributors (9) are provided above the lightweight clay layer (8). One end of each distributor (9) extends to the outside of the steel shell (1). A fan (10) is provided outside the steel shell (1) and connected to one end of the upper distributor (9).

2. The hearth heat insulation structure of a tail gas incinerator for formaldehyde production according to claim 1, characterized in that: The fixing mechanism includes a fixing seat (13), and there are several fixing seats (13). Several mounting grooves are opened on the side wall of the casting layer (6) near the ceramic fiber layer (7). The fixing seat (13) is installed in the mounting groove. A pin (14) penetrating the ceramic fiber layer (7) is provided on one side of the fixing seat (13). A cavity (22) is opened in the fixing seat (13). One end of the pin (14) extends into the cavity (22) and is connected to a hexagonal block (20). A mating groove (23) adapted to the combined structure of the hexagonal block (20) and the pin (14) is opened on the inner wall of one side of the cavity (22). The cavity (22) 2) Two sets of sliding rods (15) are symmetrically arranged inside. A fixed block (18) is connected to one end of the sliding rod (15) near the pin (14). A spring (16) and a slider (17) are sleeved on the outside of the sliding rod (15) on the side of the fixed block (18). The slider (17) is located on the side near the pin (14). An insert (19) is provided between each set of two sliders (17). The insert (19) is fixedly connected to the slider (17). The outer wall of the pin (14) is symmetrically provided with slots that are adapted to the slider (17). A pad (21) is sleeved on the outside of one end of the pin (14) on the side of the ceramic fiber layer (7).

3. The hearth heat insulation structure of a tail gas incinerator for formaldehyde production according to claim 1, characterized in that: The fastener (3) includes a support rod (11) and a pad (12). One end of the support rod (11) is welded to the inner wall of the steel shell (1), and the other end of the support rod (11) is fitted with a pad (12) on the outside of the ceramic fiber layer (7). A nut is threaded onto the side of the pad (12) away from the ceramic fiber layer (7).

4. The tail gas incinerator hearth insulation structure for formaldehyde production according to claim 1, characterized in that: The inner wall of the steel shell (1) is uniformly welded with several pre-welded parts (4), and the pre-welded parts (4) are located inside the diatomite layer (5) and the casting layer (6). The pre-welded parts (4) are Y-shaped tree structure.

5. The tail gas incinerator hearth insulation structure for formaldehyde production according to claim 2, characterized in that: The outer wall of the fixing seat (13) and the inner wall of the mounting groove are respectively provided with a number of external threads and internal threads. The cross section of the insert (19) is a right trapezoidal structure. One end of the fixing seat (13) is provided with a hexagonal groove.

6. The heat insulation structure of the furnace chamber of a formaldehyde production tail gas incinerator according to claim 1, characterized in that: The diatomite layer (5) is diatomite or a mixture of one or more clay-containing diatomite, the casting layer (6) is aluminosilicate castable or high wear-resistant castable or a mixture thereof, the ceramic fiber layer (7) is a special fiber felt with mullite crystal as the main component, and the binder is calcium aluminate cement, hydrated alumina, silica sol, alumina gel powder or phenolic resin.

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