An air preheating device for a reverberatory furnace in antimony white smelting

Abstract

This utility model relates to the field of reverberatory furnace technology, specifically an air preheating device for a reverberatory furnace used in antimony smelting. It includes a furnace enclosure, with an outer wall of the enclosure forming a bellows. A blower is installed on the upper outer side of the bellows. An air inlet pipe is located at the upper part of the bellows, and an air outlet pipe is located at the lower part. The air inlet pipe is connected to the outlet end of the blower, and the air outlet pipe is connected to the fire chamber of the reverberatory furnace. The bellows is connected to the fire plate of the furnace enclosure. In this air preheating device for an antimony smelting reverberatory furnace, the cold air supplied by the blower directly exchanges heat with the high-temperature furnace enclosure and fire plate within the annular bellows. After preheating, the air enters the fire chamber as hot air. The hot air directly participates in the combustion reaction, reducing heat loss caused by the absorption of heat by the cold air. This effectively improves the thermal efficiency of the reverberatory furnace, significantly reduces fuel consumption, and substantially lowers production costs.

Description

Technical Field

[0001] This utility model relates to the field of reverberatory furnace technology, and more specifically, to an air preheating device for a reverberatory furnace used in antimony white smelting. Background Technology

[0002] Antimony white (antimony trioxide), as an important flame retardant and chemical raw material, relies primarily on high-temperature oxidation reactions in a reverberatory furnace for its smelting process. The reverberatory furnace, as the core equipment in antimony white production, directly impacts energy consumption and costs due to its energy efficiency. Currently, the industry commonly uses blowers to directly inject ambient-temperature air into the furnace chamber for combustion (e.g., in reverberatory furnace #3). However, this method has two major technical drawbacks: first, the cold air entering the high-temperature furnace chamber absorbs a large amount of heat to raise its temperature, leading to increased fuel consumption and a thermal efficiency typically only 25-30%; second, the high temperature in the furnace chamber directly affects the furnace structure (such as the furnace lining plates, fire pit iron plates, and refractory bricks), which can easily cause overheating and damage to components during long-term operation, requiring frequent shutdowns for replacement and severely impacting production continuity.

[0003] To address these issues, various waste heat recovery technologies have been developed within the industry. For example, Chinese patent CN2258585Y discloses an "iron chimney for a flame reverberatory furnace," which employs a double-layer structure design. The inner layer discharges high-temperature flue gas, while the outer layer uses spiral heat exchange plates to preheat air using the waste heat of the flue gas, raising the air temperature to 100-250℃ and achieving energy savings to some extent. However, this technology has significant limitations: firstly, the preheating efficiency depends on the flue gas temperature, resulting in poor heat exchange stability when furnace conditions fluctuate; secondly, the preheating device is separated from the furnace and located in the chimney section, leading to significant heat loss and an inability to effectively cool critical furnace components; and thirdly, the spiral structure is prone to ash accumulation and blockage, resulting in high maintenance costs. Utility Model Content

[0004] The purpose of this utility model is to provide an air preheating device for a reverberatory furnace for antimony white smelting, in order to solve the problem mentioned in the background art that the high temperature of the furnace chamber directly acts on the furnace structure (such as the furnace surround plate, the fire pit iron plate and refractory bricks), which easily causes overheating damage to components during long-term operation, requiring frequent shutdowns for replacement, and seriously affecting the continuity of production.

[0005] To achieve the above objectives, this utility model provides an air preheating device for a reverberatory furnace used in antimony smelting, comprising a furnace enclosure plate, with a bellows forming a ring around the outer wall of the enclosure plate. A blower is installed on the upper outer side of the bellows, an air inlet pipe is provided at the upper part of the bellows, and an air outlet pipe is provided at the lower part of the bellows. The air inlet pipe is connected to the air outlet end of the blower, and the air outlet pipe is connected to the fire chamber of the reverberatory furnace. The bellows is connected to the fire plate of the furnace enclosure plate.

[0006] This setup utilizes the radiant and conductive heat from the high-temperature furnace body (especially the iron plate of the kang) to preheat the cold air inside the bellows, creating a direct heat exchange cycle of "furnace body heat dissipation - air heat absorption." The airflow provided by the blower enters from the top and exits from the bottom, following the natural upward movement of hot air, while simultaneously achieving directional cooling of key parts of the furnace body.

[0007] Preferably, the bellows has a ring structure with its inner side fitted to the furnace lining plate.

[0008] This ring structure allows the bellows and the furnace enclosure to form a 360° close heat exchange surface, ensuring that heat from all areas of the furnace is evenly transferred to the airflow, which conforms to the principle that "contact area is positively correlated with heat transfer" in heat conduction.

[0009] Preferably, the interior of the bellows is equipped with several layers from top to bottom. The layers are of a ring structure and divide the bellows into several air ducts. The layers are provided with through holes to connect the air ducts from top to bottom.

[0010] This design uses multi-layered annular plates to divide the air box into series air ducts, which increases the heat exchange time by extending the airflow path (L / d ratio). The through-hole design ensures the continuity of airflow while forcing the fluid to form sufficient disturbance in each air duct.

[0011] Preferably, the through holes between adjacent upper and lower layers are arranged in a crisscross pattern.

[0012] This setting extends the airflow path, allowing for more efficient heat exchange.

[0013] Preferably, the air box is made of high-temperature resistant stainless steel with a thickness of 5-8mm.

[0014] This design uses high-temperature resistant stainless steel (such as 310S) to take advantage of its oxidation resistance and structural stability in environments above 600℃. The 5-8mm thickness design balances thermal conductivity (thinner material is beneficial for heat transfer) and structural strength (thicker material resists thermal deformation).

[0015] Preferably, both the air inlet pipe and the air outlet pipe are equipped with flow regulating valves.

[0016] This flow regulating valve is designed to automatically adjust its opening by using the pressure difference feedback on both sides of the throttling orifice plate. When the pressure inside the furnace fluctuates, the flow cross-sectional area is changed to stabilize the air volume, which is consistent with the application scenario of Bernoulli's equation in fluid mechanics.

[0017] Preferably, the outer wall of the air box is wrapped with an insulation layer, and the insulation layer is made of aluminum silicate fiber cotton.

[0018] This feature uses aluminum silicate fiber cotton to create a static air layer by dividing the air through a high-density fiber structure. It utilizes the low thermal conductivity of air to block heat radiation and convection losses from the outer wall of the bellows. Its heat preservation mechanism is based on the principle of gas insulation.

[0019] Preferably, the distance between the inner wall of the furnace enclosure and the outer wall of the reverberatory furnace is 50cm-100cm.

[0020] This 50-100cm spacing design provides operating space for the installation of the bellows, while ensuring that the air layer between the furnace enclosure and the outer wall of the reverberatory furnace can form a natural convection buffer, preventing the high temperature of the furnace body from being directly conducted to the bellows and causing local overheating.

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0022] In this air preheating device for a reverberatory furnace used in antimony smelting, cold air supplied by a blower directly exchanges heat with the high-temperature furnace surround plate and the iron plate of the fire pit within an annular wind box. After preheating, the air enters the fire chamber as hot air (a significant improvement over the prior art document CN2258585Y). The hot air directly participates in the combustion reaction, reducing heat loss caused by the absorption of heat by cold air, effectively improving the thermal efficiency of the reverberatory furnace, significantly reducing fuel consumption, and substantially lowering production costs.

[0023] The cold air flowing inside the bellows absorbs heat and heats up, simultaneously providing forced cooling to the furnace lining plates, the kang (heated brick bed) iron plates, and the refractory bricks, resulting in a significant drop in the operating temperature of key components. This design effectively mitigates high-temperature oxidation and thermal stress damage, significantly extends the service life of the kang iron plates and furnace lining bricks, greatly reduces equipment maintenance frequency, and significantly improves production continuity.

[0024] The interior of the wind box is divided into multiple levels of air ducts by annular layers, and the through holes of adjacent layers are designed to cross left and right, forcing the airflow into a spiral upward turbulent state within the wind box. This significantly increases the contact area with the furnace lining and extends the heat exchange time considerably. Even when furnace conditions fluctuate, it can maintain a stable preheating effect, solving the problem of heat exchange fluctuations caused by flue gas temperature as described in the prior art CN2258585Y.

[0025] The annular bellows is directly fitted to the furnace enclosure, requiring no additional workshop space, making it particularly suitable for the retrofitting of small and medium-sized reverberatory furnaces. The high-temperature resistant stainless steel material ensures the bellows can withstand high operating temperatures, while the outer aluminum silicate fiber insulation layer effectively controls heat loss. For existing equipment, the retrofit can be completed simply by welding the bellows to the outside of the furnace enclosure and connecting the piping; the installation period is short, and the retrofit cost is significantly lower than that of heat pipe preheaters. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0027] Figure 2 This is a top view of the structure of this utility model;

[0028] Figure 3 This is a schematic diagram of the structure of the middle layer plate of this utility model;

[0029] The meanings of the labels in the diagram are as follows:

[0030] 1. Reverberatory furnace; 2. Furnace surround plate; 21. Fire pit iron plate; 3. Bellows; 31. Shelf; 32. Through hole; 33. Air outlet pipe; 34. Air inlet pipe; 35. Flow regulating valve; 36. Insulation layer; 4. Blower. Detailed Implementation

[0031] 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.

[0032] This utility model provides an air preheating device for a reverberatory furnace used in antimony white smelting, such as... Figure 1 , Figure 2 , Figure 3 As shown, the furnace includes a furnace enclosure 2 for a reverberatory furnace 1. The outer wall of the furnace enclosure 2 forms a bellows 3. A blower 4 is installed on the upper outer side of the bellows 3. An air inlet pipe 34 is provided on the upper part of the bellows 3. An air outlet pipe 33 is provided on the lower part of the bellows 3. The air inlet pipe 34 is connected to the air outlet end of the blower 4. The air outlet pipe 33 is connected to the fire chamber of the reverberatory furnace 1. The bellows 3 is connected to the fire kang iron plate 21 of the furnace enclosure 2.

[0033] By installing a bellows 3 on the outside of the furnace enclosure 2, the radiant and conductive heat from the high-temperature furnace body, especially the iron plate 21 used for the fire pit, is used to preheat the cold air inside the bellows 3, forming a direct heat exchange cycle of "furnace body heat dissipation - air heat absorption". The airflow provided by the blower 4 enters from the upper air inlet duct 34 and exits from the lower air outlet duct 33, following the physical characteristic of hot air rising naturally, while simultaneously achieving directional cooling of key parts of the furnace body. By combining waste heat recovery with furnace protection, heat loss caused by cold air directly entering the furnace is avoided, and the high-temperature aging of the furnace body is slowed down through airflow cooling, solving the problem of the single function of traditional devices.

[0034] In this embodiment, as Figure 2 As shown, the bellows 3 has a ring structure, and its inner side is attached to the furnace lining plate 2.

[0035] The annular wind box 3 and the furnace enclosure plate 2 form a 360° close-fitting heat exchange surface, ensuring that heat from all areas of the furnace is evenly transferred to the airflow, which conforms to the law of "contact area is positively correlated with heat transfer" in heat conduction. This eliminates local heat exchange dead zones and avoids fluctuations in preheating efficiency caused by uneven furnace temperature distribution. At the same time, the annular design makes the airflow resistance distribution more balanced and reduces air pressure loss.

[0036] Specifically, such as Figure 1 , Figure 2 As shown, the interior of the air box 3 is equipped with several layers 31 from top to bottom. The layers 31 have a ring structure and divide the air box 3 into several air ducts. The layers 31 have through holes 32 to connect the several air ducts from top to bottom.

[0037] The multi-layered annular plate 31 divides the air box 3 into series air ducts, increasing the heat exchange time by extending the airflow path L / d ratio. The through holes 32 on the plate 31 ensure airflow continuity while forcing the fluid to form sufficient turbulence in each air duct. Compared with a single-layer air box 3, the heat exchange efficiency is significantly improved, and the layered structure makes the airflow velocity distribution inside the air box 3 more uniform, avoiding local short-circuiting.

[0038] Furthermore, such as Figure 1 As shown, the through holes 32 between adjacent upper and lower layers 31 are arranged in a crisscross pattern.

[0039] The airflow is guided to change direction by the intersecting through holes 32, thereby extending the airflow path and allowing for sufficient heat exchange, thus improving the heat exchange effect between the air and the inner wall of the air box 3.

[0040] Furthermore, the bellows 3 is made of high-temperature resistant stainless steel with a thickness of 5-8mm.

[0041] The wind box 3 is made of high-temperature resistant stainless steel such as 310S. Utilizing its oxidation resistance and structural stability in environments above 600℃, the 5-8mm thickness design balances efficient heat transfer with robust structural strength to resist thermal deformation. This ensures that the wind box 3 will not crack, bulge, or fail under long-term high-temperature conditions, and its service life matches the furnace overhaul cycle.

[0042] Furthermore, such as Figure 1 As shown, flow regulating valves 35 are installed on both the air inlet pipe 34 and the air outlet pipe 33.

[0043] The flow regulating valves 35 on the air inlet pipe 34 and the air outlet pipe 33 automatically adjust their opening through pressure difference feedback on both sides of the throttling orifice plate. When the pressure inside the furnace fluctuates, the flow cross-sectional area is changed to stabilize the air volume, which conforms to the application scenario of Bernoulli's equation in fluid mechanics. This achieves dynamic matching between the preheating air volume and the combustion demand inside the furnace, avoiding furnace temperature fluctuations or incomplete fuel combustion caused by sudden changes in air volume.

[0044] Furthermore, such as Figure 1 As shown, the outer wall of the wind box 3 is wrapped with a heat insulation layer 36, which is made of aluminum silicate fiber cotton.

[0045] The insulation layer 36 on the outer wall of the air box 3 is made of aluminum silicate fiber cotton. Through its high-density fiber structure, it divides the air to form a stagnant air layer. Utilizing the low thermal conductivity of air, it blocks heat radiation and convection losses from the outer wall of the air box 3. Its insulation mechanism is based on the principle of gas insulation. This reduces the outer surface temperature of the air box 3 to within ±10℃ of the ambient temperature, controlling the heat loss rate to within 5%, thus avoiding excessively high workshop ambient temperatures and energy waste.

[0046] Furthermore, the distance between the inner wall of the furnace enclosure 2 and the outer wall of the reverberatory furnace 1 is 50cm-100cm.

[0047] The 50cm-100cm gap between the inner wall of the furnace enclosure 2 and the outer wall of the reverberatory furnace 1 provides operating space for the installation of the bellows 3, while ensuring that the air layer between the furnace enclosure 2 and the outer wall of the reverberatory furnace 1 can form a natural convection buffer, preventing the high temperature of the furnace body from being directly conducted to the bellows 3 and causing local overheating. This balances structural compactness and heat dissipation safety, and this gap range has been proven in practice to adapt to the thermal field distribution characteristics of reverberatory furnaces 1 of different specifications.

[0048] This utility model discloses an air preheating device for an antimony white smelting reverberatory furnace. Based on the principles of furnace waste heat recovery and forced convection heat transfer, it constructs a closed-loop system of "furnace heat dissipation - air heat absorption - hot air combustion assistance" by installing an annular wind box 3 outside the furnace enclosure 2 of the reverberatory furnace 1. During furnace operation, the furnace enclosure 2 and the fire-heating iron plate 21 typically reach high temperatures of 500-800℃, heating the cold air inside the wind box 3. Simultaneously, the airflow provides cooling protection for the high-temperature furnace components, achieving the dual goals of energy saving and equipment lifespan extension.

[0049] The multi-layered annular plates 31 and cross-holes 32 inside the air box 3 improve the heat exchange efficiency between air and the high-temperature furnace body by extending the airflow path and enhancing turbulence; the insulation layer 36 reduces heat loss, and the flow regulating valve 35 dynamically matches the combustion demand in the furnace to ensure stable system operation.

[0050] Work process

[0051] Cold air introduction stage: After the blower 4 is started, ambient air at about 20~30℃ is sent into the annular air box 3 through the air inlet pipe 34 at the top of the air box 3. At this time, the flow regulating valve 35 on the air inlet pipe 34 can adjust the air intake according to the real-time combustion status of the fire chamber of the reverberatory furnace 1, such as temperature and pressure. The initial air volume is usually set to a basic value that meets the needs of the oxidation reaction in the furnace.

[0052] Heat exchange stage: After cold air enters the bellows 3, it directly absorbs the radiant and conductive heat from the furnace wall 2 and the iron plate 21 of the kang (heated brick bed) because the inner side of the bellows 3 is in close contact with the furnace wall 2. The airflow flows from top to bottom in the air ducts separated by multiple annular plates 31, and each air duct is connected by through holes 32 on the plates 31. Since the through holes 32 of the upper and lower plates 31 are arranged in a crisscross pattern, the airflow needs to turn constantly, the path is extended and turbulence is formed, the contact time with the inner wall of the bellows 3 and the furnace wall 2 is increased, the heat exchange is more complete, and the air temperature gradually rises, eventually reaching 300~400℃. At the same time, the flowing cold air cools the furnace wall 2 and the iron plate 21 of the kang, reducing their operating temperature.

[0053] Hot air combustion stage: Preheated hot air enters the fire chamber of reverberatory furnace 1 through the air outlet pipe 33 at the bottom of the air box 3, participating in the high-temperature oxidation reaction of antimony white smelting. The flow regulating valve 35 on the air outlet pipe 33 is linked with the air inlet pipe 34 to finely adjust the air volume according to the real-time operating conditions in the furnace, ensuring that the hot air supply matches the fuel combustion demand and avoiding furnace temperature fluctuations.

[0054] Insulation and Stable Operation: The aluminum silicate fiber cotton insulation layer 36 on the outside of the bellows 3 reduces heat loss to the outside and maintains a high-temperature environment inside the bellows 3; the 50cm-100cm gap between the furnace enclosure 2 and the outer wall of the reverberatory furnace 1 forms an air buffer layer, preventing the high temperature of the reverberatory furnace 1 from being directly conducted to the bellows 3, ensuring long-term stable operation of the system. The entire process achieves a synergistic effect of "waste heat recovery - energy saving and consumption reduction - equipment protection", and has a compact structure that does not require a large amount of additional space, making it suitable for the efficient operation of small and medium-sized reverberatory furnaces.

[0055] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An air preheating device for a reverberatory furnace in antimony smelting, comprising a furnace enclosure plate (2) for the reverberatory furnace (1), characterized in that: The outer wall of the furnace enclosure (2) forms a bellows (3). A blower (4) is installed on the upper outer side of the bellows (3). An air inlet pipe (34) is provided on the upper part of the bellows (3). An air outlet pipe (33) is provided on the lower part of the bellows (3). The air inlet pipe (34) is connected to the air outlet end of the blower (4). The air outlet pipe (33) is connected to the fire chamber of the reverberatory furnace (1). The bellows (3) is connected to the position of the fire kang iron plate (21) of the furnace enclosure (2).

2. The air preheating device for a reverberatory furnace for antimony white smelting according to claim 1, characterized in that: The bellows (3) has a ring structure and its inner side is attached to the furnace lining plate (2).

3. The air preheating device for a reverberatory furnace for antimony white smelting according to claim 1, characterized in that: The air box (3) has several layers (31) installed inside from top to bottom. The layers (31) are ring-shaped and divide the air box (3) into several air ducts. The layers (31) have through holes (32) to connect the several air ducts from top to bottom.

4. The air preheating device for a reverberatory furnace in antimony smelting according to claim 3, characterized in that: The through holes (32) between adjacent upper and lower layers (31) are arranged in a crisscross pattern.

5. The air preheating device for a reverberatory furnace for antimony white smelting according to claim 1, characterized in that: The air box (3) is made of high-temperature resistant stainless steel with a thickness of 5-8mm.

6. The air preheating device for a reverberatory furnace in antimony smelting according to claim 1, characterized in that: Both the air inlet pipe (34) and the air outlet pipe (33) are equipped with flow regulating valves (35).

7. The air preheating device for a reverberatory furnace for antimony white smelting according to claim 1, characterized in that: The outer wall of the wind box (3) is covered with a heat insulation layer (36), which is made of aluminum silicate fiber cotton.

8. The air preheating device for a reverberatory furnace in antimony smelting according to claim 1, characterized in that: The distance between the inner wall of the furnace enclosure (2) and the outer wall of the reverberatory furnace (1) is 50cm-100cm.

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