Composite preheating device for walking beam furnace

Abstract

A composite preheating device for a walking beam furnace belongs to the technical field of metal heating equipment. It includes an air preheater and a flue. The air preheater is connected to the furnace body via a flue pipe, and a flue extends from the air preheater. A flue outlet is located at the free end of the flue. The composite preheating device also includes a combustion air blower. The inlet of the combustion air blower is connected to the combustion air intake / exhaust pipe, and the outlet of the combustion air blower is connected to a combustion air delivery pipe. This combustion air delivery pipe extends into the air preheater and connects to an inner combustion air pipe. The inner combustion air pipe extends into the flue near the flue outlet, running counter-currently to the flue gas flow and connecting its extension end to the combustion air pipe. Advantages: It collects the hot air discharged after the moving beam cools and further heats it using the residual heat in the flue. This hot air is used as combustion air, significantly reducing the amount of fuel required to reach the preheating temperature, saving energy, and reducing pollutant emissions.

Description

Technical Field

[0001] This utility model belongs to the technical field of metal heating equipment, specifically relating to a composite preheating device for a walking beam furnace. Background Technology

[0002] A walking beam furnace is a large-scale industrial heating device widely used in metallurgy, machinery, and building materials industries. It is primarily used for heating, homogenizing, or heat-treating metal workpieces such as steel billets, steel plates, steel pipes, and ingots. The workpiece is driven forward step by step by a dedicated walking beam mechanism, thus completing the conveying and heating process within the furnace. A walking beam furnace typically includes a furnace body structure, a heating system, a walking beam mechanism, and fixed beams and walking beams. The furnace body structure includes furnace walls, a furnace roof, and a furnace door, and is internally lined with refractory and insulation materials to form a high-temperature, sealed space.

[0003] The walking beam is the core moving component of the walking beam furnace. Through a set of precise mechanical movements, it automates and simplifies the entire heating process. Although the walking beam is made of heat-resistant alloy steel (such as ZG4Cr25Ni35Nb), its mechanical strength (such as yield strength) decreases significantly at high temperatures. Therefore, the walking beam is usually designed as a hollow structure, with compressed air or water cooling inside for cooling protection to prevent softening and deformation at high temperatures.

[0004] Walking beam furnaces are high-energy consumers, as the flue gas discharged from the tail end of the furnace is extremely hot. Directly releasing this high-temperature flue gas into the atmosphere would result in a huge waste of energy. The walking beam furnace preheating is a functional area integrated into the furnace structure. Its core purpose is to recover and utilize the waste heat of the flue gas to preheat the combustion air entering the furnace, thereby significantly improving the furnace's thermal efficiency and reducing fuel consumption. This area is usually referred to as the "preheating section".

[0005] The purpose of a preheating device is to turn waste into treasure. Existing preheating devices utilize the waste heat of flue gas at the furnace tail to heat the combustion medium, and the heat is recovered and then discharged through the chimney. However, waste heat is also generated during the cooling of the walking beam. Whether this waste heat can also be utilized is a question the applicant has explored. The technical solution described below arose from this context. Utility Model Content

[0006] The purpose of this invention is to provide a composite preheating device for a walking beam furnace, which can improve the thermal utilization rate of the walking beam furnace and significantly reduce fuel consumption.

[0007] The purpose of this utility model is achieved as follows: a composite preheating device for a walking beam furnace, wherein the walking beam furnace includes a furnace body, fixed beams, and moving beams. The furnace body includes a pair of furnace walls and a furnace top located on top of the pair of furnace walls. The fixed beams are fixed in pairs at the bottom of the furnace body and arranged parallel to each other along the length of the furnace body. The moving beams circulate between adjacent fixed beams to drive the workpiece forward. The moving beams have a cooling air inlet at one end of the beam cavity and a combustion air intake / exhaust pipe leading out at the other end of the beam cavity. The composite preheating device includes an air preheater and a flue. The air preheater... Installed on the top of the furnace, it is connected to the interior of the furnace body through a flue pipe. A flue is led out from the air preheater, and a flue outlet is provided at the free end of the flue. The composite preheating device also includes a combustion air blower. The air inlet of the combustion air blower is connected to the combustion air intake and exhaust pipe, and the air outlet of the combustion air blower is connected to the combustion air delivery pipe. The combustion air delivery pipe extends into the air preheater and connects to the combustion air inner pipe. The combustion air inner pipe extends into the flue near the flue outlet, and extends in the opposite direction to the flue gas in the flue towards the combustion air pipe, and the extended end is connected to the combustion air pipe.

[0008] In one specific embodiment of this utility model, the combustion air supply pipe and the combustion air inner pipe are an integral pipe.

[0009] In another specific embodiment of this utility model, the moving beam is connected to the preheated air intake and exhaust pipe via a telescopic swing joint.

[0010] In another specific embodiment of this utility model, a nozzle is installed on the furnace top, with the flame-emitting end of the nozzle protruding downward into the furnace body, and the upper end of the nozzle protruding out of the furnace body and connected to one end of the combustion air pipe and one end of the gas pipe, respectively.

[0011] In another specific embodiment of this utility model, the combustion-supporting air duct is configured with a large combustion-supporting air duct and a small combustion-supporting air duct that are connected to each other at the middle of its length direction. The small combustion-supporting air duct is provided with a small combustion-supporting air duct valve at the end that is connected to the large combustion-supporting air duct.

[0012] In another specific embodiment of this utility model, the gas introduced into the gas pipe is natural gas.

[0013] In a further specific embodiment of this utility model, the outer wall of the flue is covered with thermal insulation material.

[0014] Because of the above-mentioned structure, this utility model collects the hot air discharged after the moving beam is cooled and uses the residual heat in the flue to further heat it. This hot air is used as combustion air, which significantly reduces the amount of fuel required to reach the preheating temperature, saves energy, and can reduce pollutant emissions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model; Figure 2 This is a schematic diagram of the pipeline layout of this utility model.

[0016] In the diagram: 1. Furnace body, 11. Furnace wall, 12. Furnace top, 13. Exhaust pipe; 2. Fixed beam; 3. Moving beam, 31. Cooling air inlet, 32. Combustion air intake and exhaust pipe, 33. Telescopic swing joint; 4. Air preheater; 5. Flue, 51. Exhaust port; 6. Combustion fan, 61. Combustion air delivery pipe, 62. Inner pipe of combustion air; 7. Combustion air duct, 71. High-fire combustion air duct, 72. Low-fire combustion air duct, 73. Low-fire combustion air duct valve; 8. Nozzle; 9. Gas pipe. Detailed Implementation

[0017] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. However, the description of the embodiments is not a limitation on the technical solution. Any formal but not substantive changes made based on the concept of this utility model should be considered within the protection scope of this utility model.

[0018] In the following description, all directional (or orientational) concepts involving up, down, left, right, front, and back refer to the position of the figure being described, and are intended to facilitate public understanding. Therefore, they should not be construed as a special limitation on the technical solution provided by this utility model.

[0019] Please see Figure 1 and Figure 2 This utility model relates to a composite preheating device for a walking beam furnace. The walking beam furnace includes a furnace body 1, a fixed beam 2, and a moving beam 3. The furnace body 1 includes a pair of furnace walls 11 and a furnace top 12 located on top of the pair of furnace walls 11. A nozzle 8 is installed on the furnace top 12. The flame-emitting end of the nozzle 8 extends downward into the furnace body 1, and the upper end of the nozzle 8 extends out of the furnace body 1 and is connected to one end of a combustion air duct 7 and one end of a gas pipe 9, respectively. The gas pipe 9 carries natural gas. The combustion air duct 7 has a large-fire combustion air duct 71 and a small-fire combustion air duct 72 connected at both ends in the middle of its length. The small-fire combustion air duct 72 has a small-fire combustion air duct valve 73 at the end connected to the large-fire combustion air duct 71. The high-fire combustion-supporting air duct 71 is used in the high-load operation stage of the walking beam furnace. When a large amount of heat is required, it provides a huge air flow and high air pressure to ensure a large amount of fuel is mixed and achieves complete combustion. The low-fire combustion-supporting air duct 72 is used in the low-load operation stage of the walking beam furnace, such as during preheating, heat preservation, and standby.

[0020] The fixed beams 2 are fixed in pairs at the bottom of the furnace body 1 and arranged parallel to each other along the length of the furnace body 1. The moving beams 3 are driven by an external walking mechanism to circulate between adjacent fixed beams 2 to drive the workpiece forward. The moving beams 3 directly bear and transport high-temperature steel billets inside the furnace body 1. Although they are made of heat-resistant alloy, the temperature they withstand over a long period of time is much higher than the melting point of the material itself. In order to prevent the moving beams 3 from softening, deforming or burning at high temperatures, they must be forcibly cooled. The moving beams 3 have a cooling air inlet 31 at one end of the beam cavity, and a combustion air intake and exhaust pipe 32 is led out from the other end of the beam cavity through a telescopic swing joint 33.

[0021] The composite preheating device includes an air preheater 4, a flue 5, and a combustion air blower 6. The air preheater 4 is installed on the furnace top 12 and is connected to the furnace chamber of the furnace body 1 via a flue pipe 13. A flue 5 extends from the air preheater 4, and a flue outlet 51 is provided at the free end of the flue 5. The air inlet of the combustion air blower 6 is connected to the combustion air intake / exhaust pipe 32, and the air outlet of the combustion air blower 6 is connected to a combustion air delivery pipe 61. The combustion air delivery pipe 61 extends into the air preheater 4 and connects to the combustion air inner pipe 62. The combustion air inner pipe 62 extends into the flue 5 near the flue outlet 51, and extends in the opposite direction to the flue gas in the flue 5 towards the combustion air duct 7, connecting its extended end to the combustion air duct 7. The combustion air delivery pipe 61 and the combustion air inner pipe 62 are an integral pipe.

[0022] Existing walking beam furnaces use a single air preheater 4 for preheating. High-temperature flue gas from the furnace is discharged to the air preheater 4 to release heat. Air enters the air preheater 4 via a blower, absorbs heat from the air preheater 4, and mixes with natural gas at the combustion air duct 7 to participate in the fuel combustion process. The improvement of this invention lies in the recovery and utilization of the heat generated after cooling the moving beam 3, based on the aforementioned single air preheater 4 preheating structure. The moving beam 3 is designed as a "heat exchanger." Cooling air, as the cooling medium, enters the interior of the moving beam 3 through the cooling air inlet 31, circulating within the closed beam cavity and carrying away the heat from the moving beam 3, keeping its temperature within a safe range. The hot air formed after heating the cooling air has a high temperature and large flow rate, but in the past it was considered "waste heat" and directly discharged into the atmosphere, wasting a large amount of thermal energy and causing thermal pollution. This invention collects a portion of hot air to act as combustion air. The hot air enters the combustion air inner pipe 62 through the combustion air intake / exhaust pipe 32 via the combustion air fan 6, absorbs residual heat from the flue 5 for further heating, and then enters the combustion air duct 7 as combustion air. With the above structure, the amount of fuel required to reach the preheated temperature of the combustion air in this invention is significantly reduced, which is the most direct energy-saving benefit. Furthermore, the reduction in fuel consumption also reduces pollutant emissions, thus achieving the invention's objective.

Claims

1. A composite preheating device for a walking beam furnace, the walking beam furnace comprising a furnace body (1), fixed beams (2) and moving beams (3), the furnace body (1) comprising a pair of furnace walls (11) and a furnace top (12) located on top of the pair of furnace walls (11), the fixed beams (2) being fixed in pairs at the bottom of the furnace body (1) and arranged parallel to each other along the length of the furnace body (1), the moving beams (3) cyclically moving between two adjacent fixed beams (2) to drive the workpiece forward, the moving beams (3) in A cooling air inlet (31) is provided at one end of the beam cavity, and a combustion air intake and exhaust pipe (32) is led out at the other end of the beam cavity. The composite preheating device includes an air preheater (4) and a flue (5). The air preheater (4) is installed on the furnace top (12) and is connected to the inside of the furnace body (1) through a flue pipe (13). A flue (5) is led out from the air preheater (4), and a flue outlet (51) is provided at the free end of the flue (5). The device is characterized in that... The composite preheating device also includes a combustion-supporting fan (6), the air inlet of which is connected to the combustion-supporting air intake and exhaust pipe (32), and the air outlet of which is connected to a combustion-supporting air delivery pipe (61). The combustion-supporting air delivery pipe (61) extends into the air preheater (4) and is connected to the combustion-supporting air inner pipe (62). The combustion-supporting air inner pipe (62) extends into the flue (5) near the exhaust port (51), and extends in the opposite direction to the flue gas in the flue (5) towards the combustion-supporting air pipe (7) and connects the extended end to the combustion-supporting air pipe (7).

2. The composite preheating device for a walking beam furnace according to claim 1, characterized in that: The combustion air supply pipe (61) and the combustion air inner pipe (62) are an integral pipe.

3. The composite preheating device for a walking beam furnace according to claim 1, characterized in that: The moving beam (3) is connected to the preheated air intake and exhaust pipe (32) through a telescopic swing joint (33).

4. The composite preheating device for a walking beam furnace according to claim 1, characterized in that: The furnace top (12) is equipped with a nozzle (8), the flame-emitting end of the nozzle (8) extends downward into the furnace body (1), and the upper end of the nozzle (8) extends out of the furnace body (1) and is connected to one end of the combustion air pipe (7) and one end of the gas pipe (9) respectively.

5. The composite preheating device for a walking beam furnace according to claim 1, characterized in that: The combustion-supporting air duct (7) has a large combustion-supporting air duct (71) and a small combustion-supporting air duct (72) connected to each other at the middle of its length. The small combustion-supporting air duct (72) is provided with a small combustion-supporting air duct valve (73) at the end connected to the large combustion-supporting air duct (71).

6. The composite preheating device for a walking beam furnace according to claim 4, characterized in that: The gas introduced into the gas pipe (9) is natural gas.

7. The composite preheating device for a walking beam furnace according to claim 4, characterized in that: The outer wall of the flue (5) is covered with thermal insulation material.

Images