A furnace wall and water cooling device for a melting furnace

Abstract

The utility model discloses a furnace wall of melting furnace belongs to the field of melting furnace heat abstractor. It includes furnace wall ontology, is inlayed with water cooling device in furnace wall ontology, water cooling device includes water cooling base body, is provided with first cooling water pipe in water cooling base body, the inside surface of water cooling base body is provided with fin board, the number of fin board is greater than or equal to 2, and is provided with filler layer between two adjacent fin boards. The utility model discloses through the structure of furnace wall, especially the structure of water cooling device among them, avoids the longitudinal or transverse crack when thermal shock, guarantees the heat transfer efficiency of suitable, to form the slag skin protection furnace wall and be prevented from being worn and corroded, solved the refractory brick layer loss of furnace wall during the operation of melting furnace too fast, forced frequent shutdown technical problem, thereby realizes the long -term, continuous, safe, stable disposal of ash residue class hazardous waste of melting furnace.

Description

Technical Field

[0001] This utility model belongs to the technical field of heat dissipation devices for melting furnaces, and more specifically, relates to a furnace wall and water cooling device for a melting furnace. Background Technology

[0002] Hazardous wastes such as ash and slag (e.g., fly ash and slag from waste incineration) are classified as HW18 hazardous waste due to their accumulation of heavy metals and dioxins. The current mainstream technology is "cement solidification + safe landfill," but the volume increase ratio is as high as 1.5, resulting in high landfill land area and seepage prevention costs. Furthermore, the concentration of heavy metals leaching is prone to exceed the standard under long-term acid rain conditions, posing a risk of secondary pollution.

[0003] The glassy substance obtained from the melting process of hazardous waste such as ash and slag exhibits long-term stability and can be recycled for use as abrasives, filter materials, and roadbed materials, making it an effective measure for turning waste into treasure. The melting process for treating hazardous waste such as ash and slag has the following advantages: low carbon footprint and environmentally friendly; saves more than 30% of land compared to other treatment technologies of the same scale; can treat various types of hazardous waste such as ash and slag; generates very little secondary hazardous waste; and allows for the recovery and reuse of valuable metals from the hazardous waste.

[0004] However, when using the melting method to dispose of hazardous waste such as ash, the melting furnace typically operates continuously for about 3000 hours. The molten glass in the furnace continuously erodes and wears down the refractory brick layer of the furnace wall, and the degree of erosion is difficult to observe during continuous operation. Once the molten glass partially penetrates the refractory brick layer, it can lead to catastrophic accidents such as steel shell burn-through and molten metal leakage. Taking plasma melting furnaces as an example, in actual operation, the refractory brick layer is easily eroded at the high temperature of around 1500℃ inside the furnace because its composition is similar to that of the molten glass in the upper layer of the slag pool. Furthermore, the molten liquid continuously rotates and tumbles due to electromagnetic induction and redox reactions producing gases such as CO, further causing rapid wear of the refractory brick layer in contact with the molten glass. This means that the melting furnace, which should be operating continuously, needs to be shut down for repair or replacement every 3-4 months, and the losses from shutdown and the costs of repair and replacement are extremely high. The solution of using water-cooled walls to form a "slag skin" at the interface between the molten glass and the furnace wall to achieve "slag-resistant slag" is widely adopted. Chinese patent publication CN111876552A discloses a method for slag coating in a water-cooled electric furnace. However, when disposing of hazardous waste such as ash, this method suffers from discontinuous heat conduction due to multiple layers between the molten glass and the water-cooled wall, as well as the layering of the heat-conducting layer with the water-cooled wall. This severely affects heat transfer efficiency, preventing the water-cooled wall from cooling the molten glass in contact with it below its freezing point, thus failing to form a slag protective layer. Chinese patent publication CN207891366U discloses a cast steel cooling wall, which can solve the problem of low heat transfer efficiency in the early stages of furnace operation. However, in the later stages of furnace operation, the cast steel cooling wall is prone to longitudinal or transverse cracks due to thermal shock, similarly severely affecting heat transfer efficiency and failing to effectively utilize its cooling capacity. Consequently, the molten glass in contact with the cooling wall cannot be cooled below its freezing point, preventing the formation of a slag protective layer. Furthermore, since the cooling wall comes into direct contact with the molten liquid during the initial stage of use, a large amount of heat is carried away by the cooling water, which severely reduces the thermal efficiency of the furnace and also leads to a reduction in the effective volume of the furnace.

[0005] Therefore, when using the melting method to dispose of hazardous waste such as ash and slag, how to prevent longitudinal or transverse cracks from forming in the cast steel cooling wall due to thermal shock, thereby effectively forming a slag skin to protect the furnace wall from wear and erosion, ensuring the continuous and effective operation of the melting furnace, and reducing the number of shutdowns for furnace repair or replacement, is an urgent technical problem to be solved. Utility Model Content

[0006] 1. The problem to be solved In response to the technical problems in existing technologies for treating ash and slag hazardous waste using the melting method, where longitudinal or transverse cracks occur in the cast steel cooling wall due to thermal shock, making it impossible to effectively form a slag layer to protect the furnace wall from wear and erosion, ensure the continuous and effective operation of the melting furnace, and reduce the number of shutdowns for repair or replacement, this utility model provides a furnace wall for a melting furnace. By rationally designing the structure of the furnace wall, cracks caused by thermal shock are avoided, and each structure is kept at a suitable temperature gradient, effectively forming a slag layer to protect the furnace wall from wear and erosion. This enables the melting furnace to treat ash and slag hazardous waste in a long-term, continuous, safe, and stable manner.

[0007] 2. Technical Solution To solve the above problems, the technical solution adopted by this utility model is as follows: [The wall of a melting furnace] The first aspect of this utility model provides a furnace wall for a melting furnace, including a furnace wall body, a water cooling device embedded in the furnace wall body, the water cooling device including a water cooling base, a first cooling water pipe disposed in the water cooling base, fins disposed on the inner side of the water cooling base, the number of fins being greater than or equal to 2, and a filling layer disposed between two adjacent fins.

[0008] It should be noted that the water-cooling device embedded in the furnace wall means that the water-cooling device is embedded in the furnace wall, replacing part of the furnace wall and serving as part of the furnace wall. Without affecting slag adhesion, the water-cooling device may protrude slightly from the inner surface of the furnace wall.

[0009] Furthermore, the thickness of the inner side of the fin is greater than the thickness of the outer side.

[0010] More preferably, the cross-section of the fin is the same as the cross-section of the filling layer.

[0011] More preferably, the average thickness of the fin in the vertical direction is 30~80mm.

[0012] Furthermore, the average thickness of the fin in the vertical direction is 1 to 5 times, preferably 2 to 4 times, the average thickness of the filler layer in the vertical direction.

[0013] Furthermore, the water-cooled substrate and the fins are single components, formed by integral casting.

[0014] Furthermore, the absolute value of the difference between the thermal conductivity of the fin and the thermal conductivity of the filler layer is 1~50W / (mK), preferably 5~40W / (mK), and most preferably 10~30W / (mK).

[0015] Controlling the difference between the thermal conductivity of the fins and the thermal conductivity of the filler layer within a certain range is beneficial to improving the average heat transfer efficiency of the fins and the filler layer as a whole as a heat-conducting layer. It can effectively prevent gaps from forming at the contact surface between the fins and the filler layer due to different degrees of thermal expansion and contraction, thereby avoiding a reduction in the overall heat transfer efficiency of the heat-conducting layer.

[0016] Furthermore, in the horizontal direction, the length of the fin is greater than the length of the filling layer.

[0017] Furthermore, a protective layer is provided on the inner surface of the fin.

[0018] Furthermore, the first cooling water pipes are arranged at equal intervals, and the spacing between the first cooling water pipes is 1 to 2 times the outer diameter of the first cooling water pipes.

[0019] Furthermore, the thickness of the protective layer is 50-100mm, the length of the fin is 200-300mm, the length of the heat-conducting layer is 200-300mm, and the thickness of the water-cooled substrate is 80-130mm.

[0020] Furthermore, a second cooling water pipe is provided inside the uppermost fin plate. The second cooling water pipes are arranged at equal intervals, and the interval between the second cooling water pipes is 1 to 2 times the outer diameter of the second cooling water pipe.

[0021] Furthermore, a heat insulation layer is also provided on the outer surface of the water-cooled substrate.

[0022] Furthermore, in the material of the protective layer, Al2O3 accounts for 60%~75% by mass, SiO2 accounts for 20%~30% by mass, and the remainder is other acceptable protective layer materials; the materials of the fins and the water-cooled substrate are cast steel; in the material of the filler layer, silicon nitride accounts for 30%~50% by mass, and silicon carbide accounts for 50%~70% by mass.

[0023] The first aspect of this utility model also provides a furnace wall for a melting furnace, including a furnace wall body. A water cooling device is embedded in the furnace wall body. The water cooling device includes a plurality of water cooling units with identical structures forming a closed ring. Each water cooling unit includes a water cooling substrate. A first cooling water pipe is disposed in the water cooling substrate. A fin is disposed on the inner side of the water cooling substrate. The water cooling substrate and the fin are integrally cast as a single component. The number of fins is greater than or equal to 2. A filling layer is disposed between two adjacent fins.

[0024] [A water-cooling device for a melting furnace] The second aspect of this utility model provides a water cooling device for a melting furnace. The water cooling device includes a water cooling base, a first cooling water pipe is disposed in the water cooling base, and fins are disposed on the inner side of the water cooling base. The number of fins is greater than or equal to 2, and a filling layer is disposed between two adjacent fins.

[0025] It should be noted that the end in contact with the heat source and used for cooling is the inside, and the opposite direction is the outside.

[0026] Furthermore, the thickness of the inner side of the fin is greater than the thickness of the outer side.

[0027] More preferably, the cross-section of the fin is the same as the cross-section of the filling layer.

[0028] More preferably, the average thickness of the fin in the vertical direction is 30~80mm.

[0029] Furthermore, the average thickness of the fin in the vertical direction is 1 to 5 times, preferably 2 to 4 times, the average thickness of the filler layer in the vertical direction.

[0030] Furthermore, the water-cooled substrate and the fins are single components, formed by integral casting.

[0031] Furthermore, the absolute value of the difference between the thermal conductivity of the fin and the thermal conductivity of the filler layer is 1~50W / (mK), preferably 5~40W / (mK), and most preferably 10~30W / (mK).

[0032] Controlling the difference between the thermal conductivity of the fins and the thermal conductivity of the filler layer within a certain range is beneficial to improving the average heat transfer efficiency of the fins and the filler layer as a whole as a heat-conducting layer. It can effectively prevent gaps from forming at the contact surface between the fins and the filler layer due to different degrees of thermal expansion and contraction, thereby avoiding a reduction in the overall heat transfer efficiency of the heat-conducting layer.

[0033] Furthermore, in the horizontal direction, the length of the fin is greater than the length of the filling layer.

[0034] Furthermore, a protective layer is provided on the inner surface of the fin.

[0035] Furthermore, a first cooling water pipe is provided in the water-cooled substrate. The first cooling water pipe is arranged at equal intervals, and the interval between the first cooling water pipes is 1 to 2 times the outer diameter of the first cooling water pipe.

[0036] Furthermore, the thickness of the protective layer is 50-100mm, the length of the fin is 200-300mm, the length of the heat-conducting layer is 200-300mm, and the thickness of the water-cooled substrate is 80-130mm.

[0037] Furthermore, a second cooling water pipe is provided inside the uppermost fin plate. The second cooling water pipes are arranged at equal intervals, and the interval between the second cooling water pipes is 1 to 2 times the outer diameter of the second cooling water pipe.

[0038] Furthermore, a heat insulation layer is also provided on the outer surface of the water-cooled substrate.

[0039] Furthermore, in the material of the protective layer, Al2O3 accounts for 60%~75% by mass, SiO2 accounts for 20%~30% by mass, and the remainder is other acceptable protective layer materials; the materials of the fins and the water-cooled substrate are cast steel; in the material of the filler layer, silicon nitride accounts for 30%~50% by mass, and silicon carbide accounts for 50%~70% by mass.

[0040] The first aspect of this utility model also provides a water cooling device for a melting furnace. The water cooling device includes several water cooling units with the same structure forming a closed ring. Each water cooling unit includes a water cooling base. A first cooling water pipe is disposed in the water cooling base. A fin is disposed on the inner side of the water cooling base. The water cooling base and the fin are integrally cast single components. The number of fins is greater than or equal to 2. A filling layer is disposed between two adjacent fins.

[0041] [A method for coating molten glass with dross] The third aspect of this utility model provides a method for coating molten glass with slag, using a melting furnace having the furnace wall of the melting furnace provided in the first aspect of this utility model or a melting furnace having a water cooling device of the melting furnace provided in the second aspect of this utility model, wherein the height of the water cooling device covers the thickness of the molten glass, the temperature gradient of the fins is 1000℃~80℃, and the temperature gradient of the filling layer is 1000℃~200℃.

[0042] Furthermore, the thickness of the molten glass liquid is 75% to 95% of the height of the water cooling device, the temperature gradient of the protective layer is 1000℃ to 1200℃, the inlet temperature of the first cooling water pipe is 1℃ to 45℃, the temperature difference between the outlet temperature and the inlet temperature of the first cooling water pipe does not exceed 10℃, the water flow velocity in the first cooling water pipe is 2 to 4 m / s, and the thickness of the slag layer formed by the molten glass liquid is 50 to 150 mm.

[0043] [A melting furnace] The fourth aspect of this utility model provides a melting furnace having a furnace wall as provided in the first aspect of this utility model or a water cooling device as provided in the second aspect of this utility model.

[0044] 3. Beneficial effects Compared with the prior art, the beneficial effects of this utility model are as follows: (1) This utility model provides a furnace wall for a melting furnace. By rationally designing the structure of the furnace wall, especially the structure of the water cooling device, longitudinal or transverse cracks are avoided during thermal shock, ensuring appropriate heat transfer efficiency. A slag layer is formed to protect the furnace wall from wear and erosion, solving the technical problem of rapid wear of the refractory brick layer of the furnace wall and forced frequent shutdowns during the operation of the melting furnace. Specifically, the fins are set on one side of the water cooling substrate, forming an integral whole with the water cooling substrate. This avoids a serious decrease in heat transfer efficiency caused by the discontinuity between the heat-conducting layer and the water cooling substrate, ensuring that the thermal conductivity of the water cooling device is fully reflected in the heat transfer efficiency. Moreover, the fins, which form an integral whole with the water cooling substrate, can provide better support and fixation for the filling layer. The heat-conducting layer formed by the alternating interlocking of the fins and the filling layer can avoid cracks during thermal shock and reduce the impact on heat transfer efficiency. This is because the alternating interlocking structure allows the filling layer to share the stress changes caused by the thermal expansion and contraction of the fins.

[0045] In summary, the furnace wall provided by this utility model can ensure that the temperature of the inner side of the furnace wall remains below the solidification point of the molten glass, allowing it to cool and form a slag skin, thereby enabling the furnace to dispose of hazardous waste such as ash and slag in a long-term, continuous, safe, and stable manner.

[0046] (2) This utility model provides a furnace wall for a melting furnace, with fins that are thicker on the inside and narrower on the outside. This prevents the filler layer from falling off due to its own weight and the compressive force of the fins' thermal expansion, and firmly fixes the filler layer between adjacent fins, thereby improving the overall heat transfer efficiency of the heat-conducting layer. It can also increase the contact area between the fins and the filler layer, increasing the stress change of the fins during thermal expansion and contraction that the filler layer shares, further preventing the generation of cracks during thermal shock. At the same time, it also relatively increases the contact area between the fins and the protective layer, which is conducive to giving full play to the heat transfer effect of the fins and the water-cooled substrate as a single component.

[0047] (3) This utility model provides a furnace wall for a melting furnace. Since the length of the fins in the horizontal direction is greater than the length of the filling layer, the inner side of the heat-conducting layer formed by the fins and the filling layer forms a groove. The heat-conducting layer and the solid slag skin are fixed by the dovetail groove on the surface, which prevents the slag skin from falling off, thereby protecting the heat-conducting layer from the erosion of the molten glass and ensuring that the water-cooling device forms a slag skin in a long-term and stable manner.

[0048] (4) This utility model provides a furnace wall for a melting furnace, which also includes a protective layer. The protective layer can prevent the molten glass liquid from directly contacting the fins and the filling layer, protect the fins and the filling layer from the erosion and wear of the molten glass liquid, and also prevent excessive cooling due to direct contact, thereby reducing the thermal efficiency of the melting furnace and thus avoiding energy waste and reduction of the effective volume of the melting furnace.

[0049] (5) This utility model provides a furnace wall for a melting furnace. By setting cooling water pipes in the uppermost fins, the cooling of the surface of the molten glass can be enhanced, which is conducive to the formation of a slag layer and reduces the scouring and corrosion effects of the "wave effect" on the surface of the molten glass. At the same time, the wear resistance of the fins is better, which is more conducive to coping with the scouring of the molten glass at the liquid surface.

[0050] (6) This utility model provides a furnace wall for a melting furnace, wherein the water cooling device is composed of several water cooling units with the same structure, which can reduce the manufacturing and construction difficulty of the water cooling device and is conducive to the promotion and application of the furnace wall in industry.

[0051] (7) This utility model also provides a water cooling device for a melting furnace. By rationally designing the structure of the water cooling device, longitudinal or transverse cracks are avoided during thermal shock, ensuring appropriate heat transfer efficiency, so as to form a slag skin to protect the furnace wall from wear and erosion. This solves the technical problem of the furnace wall refractory brick layer being worn out too quickly and forced to shut down frequently during the operation of the melting furnace.

[0052] (8) This utility model also provides a melting furnace, the furnace wall of which can effectively form a slag skin, protect the furnace wall from wear and erosion, avoid steel shell burn-through and melt leakage, and realize the long-term, continuous, safe and stable disposal of ash and slag hazardous waste by the melting furnace. Attached Figure Description

[0053] Figure 1 This is a cross-sectional schematic diagram of the plasma melting furnace in Embodiment 1 of this utility model; Figure 2 This is a partial cross-sectional schematic diagram of the furnace wall of the plasma melting furnace in Embodiment 1 of this utility model; Figure 3 This is a schematic diagram of the slag paste layer and the thickness of each layer of the furnace wall in the plasma melting furnace of Embodiment 1 of this utility model; Figure 4 This is a partial three-dimensional structural diagram of the cooling device in the furnace wall of the plasma melting furnace in Embodiment 1 of this utility model; Figure 5 This is a partial cross-sectional schematic diagram of the furnace wall of the plasma melting furnace in Embodiment 3 of this utility model; Figure 6 This is a partial cross-sectional schematic diagram of the furnace wall of the plasma melting furnace in Embodiment 4 of this utility model; Figure 7 This is a top view of the water-cooling device for the plasma melting furnace in Embodiment 5 of this utility model; Figure 8 This is a three-dimensional structural diagram of the water-cooling unit in the water-cooling device of the plasma melting furnace in Embodiment 5 of this utility model.

[0054] In the picture: 1. Slag paste layer; 2. Protective layer; 3. Water cooling device; 31. Fin plate; 32. Filler layer; 33. Water cooling substrate; 34. First cooling water pipe; 35. Second cooling water pipe; 4. Water cooling unit; 5. Insulation layer; 6. Plasma; 7. Gas phase; 8. Molten glass liquid; 9. Molten alloy liquid; 10. Metal shell of melting furnace; 11. Refractory brick layer; 12. Water cooling device module. Detailed Implementation

[0055] It should be noted that when a component is referred to as being "mounted" on another component, it can be directly on the other component or the two components can be integrated as one unit; when a component is referred to as being "connected" to another component, it can be directly connected to the other component or the two components can be integrated as one unit. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this utility model.

[0056] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.

[0057] As used herein, “adjacent” means that two structures or elements are close to each other. Specifically, elements identified as “adjacent” may be adjacent or connected. Such elements may also be close to or near each other without necessarily touching. In some cases, the precision of proximity may depend on the specific context.

[0058] It should be noted that the side of each structure of the water-cooling device closest to the plasma melting furnace cavity is the hot end face, and the other side is the cold end face.

[0059] The present invention will be further described below with reference to specific embodiments.

[0060] Example 1 This embodiment provides a plasma melting furnace, the cross-sectional view of which is shown below. Figure 1 As shown, a water-cooling device 3 is installed on the inner side of the furnace wall of the plasma melting furnace. The water-cooling device 3 is embedded in the furnace wall, replacing part of the refractory brick layer 11 of the furnace wall. Without affecting slag adhesion, the water-cooling device 3 can protrude slightly from the inner side of the furnace wall. The water-cooling device 3 is arranged from the inside out as follows: a protective layer 2, a heat-conducting layer, a water-cooling substrate 33, and a heat-insulating layer 5. The heat-conducting layer includes fins 31 and a filling layer 32 located between the fins 31. The outer side of the heat-insulating layer 5 is the molten metal shell 10 of the plasma melting furnace.

[0061] like Figures 1-4As shown, the thickness d2 of the protective layer 2 is 50~100mm. It is used to protect the inner surface of the heat-conducting layer, i.e., the hot end face of the heat-conducting layer, during the initial stage of furnace operation. This prevents direct contact between the molten glass 8 and the heat-conducting layer and protects the hot end face of the heat-conducting layer from erosion by the molten glass 8. The material of the protective layer 2 can be determined according to the composition of the molten glass 8, while also considering factors such as the alkalinity of the molten glass 8, the refractoriness of the protective layer 2, thermal shock stability, apparent porosity, thermal conductivity, and cost. For example, when a plasma melting furnace is used to treat the residue after incineration of hazardous waste, the molten glass 8 is mainly composed of silicate-based glass with low alkalinity. The material of the protective layer 2 can be a mixed material with an Al2O3 content of 60% to 75% by mass. This mixed material also contains a small amount of SiO2, accounting for 20% to 30% by mass. Since the material of the protective layer 2 is similar to that of the molten glass 8, the protective layer 2 is continuously eroded and assimilated by the molten glass 8 as the molten slag pool operates. However, the molten glass 8 near the hot end of the heat-conducting layer forms a slag skin with constantly changing composition due to cooling, which acts as a new protective layer to isolate the molten glass 8 and protect the heat-conducting layer. Alternatively, the material of the protective layer 2 can be chromium corundum or zirconium corundum to avoid erosion by the molten glass 8, always acting as the protective layer 2 to isolate the molten glass 8 and protect the heat-conducting layer from its erosion.

[0062] The temperature of the hot end face of the protective layer 2 is controlled at around 1200℃, lower than the solidification point of the molten glass 8, ensuring that the molten glass 8 begins to solidify at the hot end face of the protective layer 2, forming a slag skin. The cold end face temperature is controlled at around 1000℃ to avoid excessive cooling that would result in an excessively thick slag layer 1, ensuring the effective volume of the plasma melting furnace while maintaining its thermal efficiency and avoiding energy waste. Of course, the thermal conductivity of the protective layer 2 should not be too low to avoid hindering the cooling effect of the heat-conducting layer.

[0063] The thickness d3 of the heat-conducting layer is 200~300mm. The fins 31 and the filler layer 32 are alternately interlocked and mutually supported and fixed. The fins 31 are integrally cast with the water-cooled substrate 33, or can be welded to the water-cooled substrate 33. This avoids a severe decrease in heat transfer efficiency caused by a break between the heat-conducting layer and the water-cooled substrate, and also prevents gaps or further widening of the gaps between the heat-conducting layer and the water-cooled substrate 33 due to thermal expansion and contraction during thermal shock, thus preventing a further decrease in heat transfer efficiency. The filler layer 32 is used to resist and absorb stress changes caused by the thermal expansion and contraction of the fins 31 during thermal shock, preventing cracks in the fins 31 due to thermal expansion and contraction, and thus preventing a severe decrease in the heat transfer efficiency of the heat-conducting layer. The fins 31 and the filler layer 32 are made of different materials. The fins 31 can be made of materials with high thermal conductivity and high melting point, such as cast steel, with a thermal conductivity of about 40~50 W / (mK) and a melting point of about 1450~1520℃. The filler layer 32 can be made of a mixed material composed of silicon nitride and silicon carbide. The silicon nitride content is 30%~50%, which acts as a flexible material to resist the stress changes of thermal expansion and contraction of the fins 31 during thermal shock absorption. The silicon carbide content is 50%~70%, which acts as a rigid material to support and fix the fins 31, and at the same time resists the wear of the protective layer 2 on the hot end face of the heat-conducting layer under special conditions, thereby improving the wear resistance, corrosion resistance, and oxidation resistance of the heat-conducting layer. The thermal conductivity of silicon nitride is approximately 20-30 W / (mK), while that of silicon carbide is approximately 80-120 W / (mK). The overall thermal conductivity of the filler layer 32 is approximately 50-90 W / (mK), which is not significantly different from that of the fin 31, thus contributing to the overall heat transfer efficiency of the heat-conducting layer. The good heat transfer efficiency of the heat-conducting layer can fully utilize the cooling capacity of the water-cooled substrate 33, ensuring that the slag paste layer 1 and the protective layer 2 are within a suitable temperature range. This ensures the formation of a slag skin while avoiding energy waste and reduction in the effective furnace volume caused by excessive cooling, thereby guaranteeing the long-term, safe, and stable operation of the molten slag pool. The material of the fin 31 can also be copper, tungsten-copper alloy, or molybdenum.

[0064] A small amount of thermally conductive adhesive is added to the joint between the fin 31 and the filler layer 32. The main components of the adhesive can be the same as those of the filler layer 32 to improve the integrity of the fin 31 and the filler layer 32, reduce the impact of the thermally conductive layer joint structure on the heat transfer efficiency, and also prevent the infiltration of molten glass 8, thereby reducing the impact on the heat transfer efficiency of the thermally conductive layer.

[0065] The hot end temperature of the fin plate 31 in the heat-conducting layer is controlled at around 1000℃ and the cold end temperature is controlled at around 80℃. The hot end temperature of the filler layer 32 is controlled at around 1000℃ and the cold end temperature is controlled at around 200℃. This precise control of the temperature gradient is due to the good heat transfer efficiency of the heat-conducting layer.

[0066] The thickness d4 of the water-cooled substrate 33 is 80~130mm. A first cooling water pipe 34 is disposed within the water-cooled substrate 33. The spacing between the first cooling water pipes 34 is 1.5 times the outer diameter of the first cooling water pipe 34. The inlet water temperature of the first cooling water pipe 34 is not higher than 45℃, and the temperature difference between the outlet water temperature and the inlet water temperature does not exceed 10℃. For example, the inlet water temperature of the first cooling water pipe 34 is 20℃, and the outlet water temperature is 30℃. The water flow velocity in the first cooling water pipe 34 is 2~4m / s, and the water pressure is 3~5bar. The arrangement of the cooling water pipes within the water-cooled substrate 33 is a conventional arrangement, which can be referenced from the arrangement in the prior art of Chinese Patent Document Publication No. CN111876552A, or as follows... Figure 8 As shown, a staggered arrangement is used to enhance the disturbance of the cooling water flow path and improve heat exchange efficiency.

[0067] The hot end temperature of the water-cooled substrate 33 is controlled at around 80℃, and the cold end temperature is controlled at around 50℃. This temperature gradient ensures the structural safety of the water-cooled substrate 33 and prevents the formation of bubbles on the inner surface of the first cooling water pipe 34 due to localized overheating, which could induce "film boiling" and lead to deterioration of heat transfer. It also reduces the tendency of calcium and magnesium ions to precipitate in the cooling water, preventing scale formation that would reduce cooling efficiency and clog pipes.

[0068] In addition, the moderately thick protective layer 2, the heat-conducting layer, and the high melting point of the heat-conducting layer can provide triple safety protection for the water-cooled substrate 33, preventing steam explosion when the molten glass liquid 8 corrodes the water-cooled substrate 33.

[0069] The thickness d5 of the heat insulation layer 5 is 30~60mm. The heat insulation layer 5 can effectively reduce air circulation and prevent corrosion from occurring on the cold end face of the water-cooled substrate 33 and the inner wall of the molten furnace metal shell 10 due to the condensation of water vapor in the air.

[0070] In the initial stage of operation, the plasma melting furnace heats up to 5000℃~8000℃. The hazardous waste, such as ash and slag, inside the furnace begins to melt and gradually separates into upper and lower layers. Figure 1As shown, the lower layer is molten alloy liquid 9, and the upper layer is molten glass liquid 8. The temperature of the gas phase 7 in the melting furnace is about 1300℃, and the temperature of the liquid phase is about 1500℃. At this time, because the liquid level of the molten glass liquid in the plasma melting furnace is low, the protective layer 2 can prevent the hot end face of the heat-conducting layer from directly facing the heat radiation of the heat source, thereby preventing the fins 31 and the filling layer 32 from developing gaps or widening gaps due to uneven heating of the hot end face of the heat-conducting layer. In the later stage of operation, a slag layer 1 with blurred solid-liquid boundary is formed at the junction of the molten glass liquid 8 and the protective layer 2 due to cooling. This is because the crystalline properties of the molten glass liquid 8 are different. The thickness of the slag layer 1 is 50~150mm. The slag layer 1 within this thickness range can ensure that the hot end face of the protective layer 2 can form a slag skin to resist the wear of slag solids and the erosion of the molten glass liquid 8, and can also avoid reducing the effective volume in the melting furnace. As the liquid level of the molten glass liquid 8 continues to rise, the plasma melting furnace reaches the upper limit of its operating load. At this point, the water cooling device 3 needs to at least cover the molten glass layer, such as Figure 3 As shown, the highest point of the cross-section of the water-cooling device 3 is higher than the top of the molten glass layer, and the lowest point of the cross-section of the water-cooling device 3 is lower than the bottom of the molten glass layer. In particular, the cooling effect of the water-cooling device 3 is optimal when the thickness of the molten glass layer is 75% to 95% of the height of the cross-section of the water-cooling device 3.

[0071] Example 2 This embodiment provides a plasma melting furnace, differing from Embodiment 1 in that the fin 31 has a trapezoidal cross-section, and the side length of this trapezoid near the hot end is greater than the side length near the cold end, meaning the thickness of the hot end of the fin 31 is greater than the thickness of the cold end. The filler layer 32 has a triangular or trapezoidal cross-section. Most preferably, the cross-section of the fin 31 is the same as the cross-sectional shape of the filler layer 32, such as... Figure 2 As shown.

[0072] The wedge-shaped structure of alternating interlocking fins 31 and filler layer 32 effectively prevents the filler layer 32 from detaching due to its own weight and the compressive force of thermal expansion of fins 31, firmly fixing the filler layer 32 between adjacent fins 31. This ensures a tight fit and good contact between fins 31 and filler layer 32. Furthermore, as the temperature rises, the contact between fins 31 and filler layer 32 becomes increasingly tight under the stress of thermal expansion, preventing the infiltration of molten glass 8 and improving the overall heat transfer efficiency of the thermally conductive layer. It also increases the contact area between fins 31 and filler layer 32, increasing the stress distribution of fins 31 during thermal expansion and contraction, further preventing cracks during thermal shock. Simultaneously, it relatively increases the contact area between fins 31 and protective layer 2, facilitating the full utilization of the heat transfer function of the fins 31 and the water-cooled substrate 33 as a single component.

[0073] Example 3 This embodiment provides a plasma melting furnace, which differs from Embodiment 2 in that the length of the fin 31 in the horizontal direction is greater than the length of the filling layer 32, and the hot end face of the heat-conducting layer forms a groove, such as... Figure 5 As shown, the heat-conducting layer and the protective layer 2 are fixed by the dovetail groove on the surface, so as to prevent the protective layer 2 from falling off.

[0074] Example 4 This embodiment provides a plasma melting furnace, which differs from Embodiment 2 in that a second cooling water pipe 35 is provided inside the uppermost fin plate 31, such as... Figure 6 As shown.

[0075] Because the surface of the molten glass 8 is closer to the heat source plasma 6, the temperature at the surface is higher than the temperature below the surface, making the molten glass 8 at the surface more susceptible to erosion and corrosion. Furthermore, the "wave effect" of the molten glass 8 surface further exacerbates the erosion and corrosion of the furnace wall. The second cooling water pipe 35 installed in the uppermost fin 31 enhances the cooling of the molten glass 8 surface, facilitating the formation of the slag layer 1 and reducing the impact of the "wave effect." Simultaneously, the fin 31 has superior wear resistance, making it more effective in coping with the erosion caused by the molten glass 8 at the surface.

[0076] Example 5 This embodiment provides a plasma melting furnace, including a water-cooling device module 12, such as... Figure 7 As shown, the furnace includes eight identical water-cooling units 4, which form a closed ring and are embedded in the furnace wall, replacing a portion of the refractory brick layer 11 that serves as the furnace wall. The cross-sectional view of this water-cooling unit 4 is shown in the figure. Figure 2 Similarly, the water-cooled unit 4 is provided with a protective layer 2, a heat-conducting layer, a water-cooled substrate 33 and a heat insulation layer 5 from the inside out. The heat-conducting layer includes fins 31 and a filling layer 32 located between the fins 31. The outer side of the heat insulation layer 5 is the molten metal shell 10 of the plasma melting furnace.

[0077] The material of the protective layer 2 can be selected based on the composition of the molten glass 8, taking into account factors such as the alkalinity of the molten glass 8, the refractoriness, thermal shock stability, apparent porosity, thermal conductivity, and cost of the protective layer 2. For example, when a plasma melting furnace is used to process the residue after incineration of hazardous waste, the molten glass 8 is mainly composed of silicate-based glass with low alkalinity. The material of the protective layer 2 can be a mixed material with an Al2O3 mass ratio of 60% to 75%; at the same time, this mixed material contains a small amount of SiO2, with a mass ratio of 20% to 30%. The hot end temperature of the protective layer 2 is controlled at around 1200℃, and the cold end temperature is controlled at around 1000℃.

[0078] The heat-conducting layer includes fins 31 and a filler layer 32, which are alternately interlocked and mutually supported and fixed. The thickness of the hot end face of the fin 31 is greater than the thickness of the cold end face. The cross-section of the filler layer 32 is triangular or trapezoidal. The fins 31 and the filler layer 32 are alternately interlocked to form a wedge-shaped structure. The length of the fin 31 in the horizontal direction is greater than the length of the filler layer 32. The hot end face of the heat-conducting layer forms a groove, so that the heat-conducting layer and the protective layer 2 are interlocked and fixed by the dovetail grooves on the surface, preventing the protective layer 2 from falling off. The fins 31 are integrally cast with the water-cooled substrate 33, or they can be welded to the water-cooled substrate 33. The fins 31 can be made of materials with high thermal conductivity and high melting point, such as cast steel, with a thermal conductivity of about 40~50 W / (mK) and a melting point of about 1450~1520°C. The filler layer 32 can be made of a mixture of silicon nitride and silicon carbide, with silicon nitride content of 30%~50% and silicon carbide content of 50%~70%. Silicon nitride has a thermal conductivity of approximately 20~30 W / (mK), while silicon carbide has a thermal conductivity of approximately 80~120 W / (mK). The overall thermal conductivity of the filler layer 32 is approximately 50~90 W / (mK), which is not significantly different from that of the fin 31, thus contributing to the overall heat transfer efficiency of the heat-conducting layer. The hot end temperature of the fin 31 in the heat-conducting layer is controlled at approximately 1000℃, and the cold end temperature is controlled at approximately 80℃. The hot end temperature of the filler layer 32 is controlled at approximately 1000℃, and the cold end temperature is controlled at approximately 200℃.

[0079] A first cooling water pipe 34 is installed inside the water-cooled substrate 33. The spacing between the first cooling water pipes 34 is 1.5 times the outer diameter of the first cooling water pipe 34. The inlet water temperature of the first cooling water pipe 34 is not higher than 45℃, and the temperature difference between the outlet water temperature and the inlet water temperature is not more than 10℃. For example, the inlet water temperature of the first cooling water pipe 34 is 20℃, and the outlet water temperature is 30℃. The water flow velocity in the first cooling water pipe 34 is 2~4m / s, and the water pressure is 3~5bar. The hot end face temperature of the water-cooled substrate is controlled at around 80℃, and the cold end face temperature is controlled at around 50℃.

[0080] The heat insulation layer 5 is used to prevent internal corrosion of the water-cooled substrate 33 and the molten furnace metal shell 10.

[0081] The above description is an illustrative description of the present invention and its embodiments. This description is not restrictive, and the embodiments shown are only one possible implementation of the present invention; actual implementations are not limited to these. Therefore, if those skilled in the art, inspired by this description, design similar implementations and examples without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A furnace wall for a melting furnace, comprising a furnace wall body, characterized in that, The furnace wall body is embedded with a water cooling device (3). The water cooling device (3) includes a water cooling base (33). A first cooling water pipe (34) is provided inside the water cooling base (33). A fin plate (31) is provided on the inner side of the water cooling base (33). The number of fin plates (31) is greater than or equal to 2. A filling layer (32) is provided between two adjacent fin plates (31).

2. The furnace wall of the melting furnace according to claim 1, characterized in that, The thickness of the inner side of the fin (31) is greater than the thickness of the outer side.

3. The furnace wall of the melting furnace according to claim 2, characterized in that, In the horizontal direction, the length of the fin (31) is greater than the length of the filling layer (32).

4. The furnace wall of the melting furnace according to claim 1, characterized in that, The inner surface of the fin (31) is provided with a protective layer (2).

5. The furnace wall of the melting furnace according to claim 4, characterized in that, The first cooling water pipes (34) are arranged at equal intervals, and the spacing between the first cooling water pipes (34) is 1 to 2 times the outer diameter of the first cooling water pipes (34); The protective layer (2) has a thickness of 50~100mm, the fin plate (31) has a length of 200~300mm, the filler layer (32) has a length of 200~300mm, and the water-cooled substrate (33) has a thickness of 80~130mm.

6. The furnace wall of the melting furnace according to claim 1, characterized in that, A second cooling water pipe (35) is provided inside the uppermost fin plate (31).

7. A furnace wall for a melting furnace, comprising a furnace wall body, characterized in that, The furnace wall body is embedded with a water cooling device (3). The water cooling device (3) includes several water cooling units (4) with the same structure forming a closed ring. The water cooling unit (4) includes a water cooling substrate (33). A first cooling water pipe (34) is provided inside the water cooling substrate (33). A fin (31) is provided on the inner side of the water cooling substrate (33). The number of fins (31) is greater than or equal to 2. A filling layer (32) is provided between two adjacent fins (31).

8. A water-cooling device for a melting furnace, characterized in that, The water cooling device (3) includes a water cooling base (33), a first cooling water pipe (34) is provided inside the water cooling base (33), and fins (31) are provided on the inner side of the water cooling base (33). The number of fins (31) is greater than or equal to 2, and a filling layer (32) is provided between two adjacent fins (31).

9. A water-cooling device for a melting furnace, characterized in that, The water cooling device (3) includes several water cooling units (4) with the same structure forming a closed ring. Each water cooling unit (4) includes a water cooling base (33). A first cooling water pipe (34) is provided inside the water cooling base (33). A fin (31) is provided on the inner side of the water cooling base (33). The number of fins (31) is greater than or equal to 2. A filling layer (32) is provided between two adjacent fins (31).

10. A melting furnace, comprising a furnace wall, characterized in that, The furnace wall is embedded with a water cooling device (3), which includes a water cooling base (33), a first cooling water pipe (34) is provided inside the water cooling base (33), and fins (31) are provided on the inner side of the water cooling base (33). The number of fins (31) is greater than or equal to 2, and a filling layer (32) is provided between two adjacent fins (31).

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