Waste heat utilization system for high-temperature flue gas rotary furnace

Abstract

The utility model discloses a high-temperature flue gas rotary furnace waste heat utilization system which comprises a rotary cooling furnace and a rotary heating furnace, the rotary cooling furnace and the rotary heating furnace both comprise furnace bodies, heat accumulators are arranged in the furnace bodies, a kiln tail cover and a kiln head cover are distributed at the two ends of the furnace bodies, and lifting plates are arranged on the inner walls of the furnace bodies; the high-temperature flue gas pipe is connected with a kiln tail cover of the rotary cooling furnace, a kiln head cover of the rotary cooling furnace is sequentially connected with the dust remover, the induced draft fan, the chimney and the normal-temperature gas pipe through the cooling flue gas pipe, and the heating gas pipe is connected with the kiln tail cover of the rotary heating furnace; the storage bin is arranged at the bottom of a kiln tail cover of the rotary cooling furnace, the discharge valve is arranged at the bottom of the storage bin and connected with a kiln head cover of the rotary heating furnace through the high-temperature feeder, and the bottom of the kiln tail cover of the rotary heating furnace is connected with the kiln head cover of the rotary cooling furnace through the feeding end of the elevator of the feeder and the discharging end of the elevator. According to the system, the maximum utilization of the high-temperature flue gas waste heat is realized.

Description

Technical Field

[0001] This utility model relates to high-temperature flue gas treatment technology, and in particular to a rotary kiln waste heat utilization system for recovering and utilizing the waste heat of high-temperature flue gas generated by industrial kiln combustion. Background Technology

[0002] my country is a major industrial country, producing more than half of the world's industrial raw materials such as steel, cement, and glass. The production of these raw materials utilizes industrial kilns, consuming large quantities of energy sources such as coal and natural gas. The combustion of these energy sources generates substantial amounts of high-temperature flue gas, which has extremely high waste heat recovery value. Currently, my country is vigorously developing a low-carbon economy, and energy conservation and carbon reduction are crucial tasks for the development of Chinese industrial enterprises. Therefore, effectively utilizing the waste heat from high-temperature flue gas has significant economic and social value.

[0003] Currently, high-temperature flue gas treatment in my country often employs fume hoods to first recover waste heat from the high-temperature flue gas, converting its calorific value into pressurized steam for use in power generation. For medium- and low-temperature flue gas, wet scrubbing and other cooling and dust removal processes are typically used. While this method recovers some waste heat from the high-temperature flue gas, assuming a 60% recovery rate and a 20% conversion rate for steam power generation, after deducting the waste heat dissipation from the medium- and low-temperature flue gas, the overall waste heat utilization rate is only about 10%. Therefore, it is evident that the waste heat utilization efficiency of high-temperature flue gas in current industrial systems remains at a low level, urgently requiring the development of new waste heat recovery and utilization technologies.

[0004] Traditional high-temperature flue gas waste heat utilization is based on heat exchange between high-temperature flue gas and water, converting the flue gas into pressurized steam. High-temperature flue gas, in terms of its physical properties, is waste gas produced by combustion, primarily composed of N2, CO2, and H2O. This means that oxygen in the air has been consumed and converted into CO2 and H2O, and it contains a high concentration of dust, rendering its components unusable. The emission of high-temperature flue gas often corresponds to the air or oxygen required for combustion. Using high-temperature flue gas to heat materials is the most efficient way to utilize waste heat resources. Directly using it to heat air or oxygen would be the best approach to achieving waste heat utilization. In industrial production, high-temperature flue gas has been used to dry and heat solid raw materials such as ores, but there are still few cases of directly heating air with high-temperature flue gas. The main reason is the low efficiency of heat conduction between gases, and the ineffective utilization of oxygen and energy in convective heat transfer when high-temperature flue gas and air are mixed together. Smelting and other production enterprises often need to directly use coal gas or other combustion to heat the hot blast stove. Because the high-temperature flue gas contains a lot of dust, the heat storage function of the checker bricks in the hot blast stove will be blocked by dust, thus losing its heat storage function and becoming unusable. Summary of the Invention

[0005] Purpose of the utility model: This utility model provides a high-temperature flue gas rotary furnace waste heat utilization system, thereby maximizing the utilization of high-temperature flue gas waste heat.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A high-temperature flue gas rotary kiln waste heat utilization system includes a high-temperature flue gas pipe, a rotary cooling furnace, a rotary heating furnace, a heat storage body, a storage silo, a discharge valve, a high-temperature feeder, a feeder, an elevator, a cooling flue gas pipe, a dust collector, an induced draft fan, a chimney, a normal temperature gas pipe, and a heating gas pipe.

[0008] Both rotary cooling furnace and rotary heating furnace include a bracket, support rollers, furnace body, kiln tail hood, kiln head hood, and lifting plate. The furnace body is supported on the support rollers, which are fixed on the bracket. A heat storage body is installed inside the furnace body. The kiln tail hood and kiln head hood are distributed at both ends of the furnace body, and the lifting plate is installed on the inner wall of the furnace body.

[0009] The high-temperature flue gas pipe is connected to the kiln tail hood of the rotary cooling furnace. The kiln head hood of the rotary cooling furnace is connected to the dust collector, induced draft fan, and chimney in sequence through the cooling flue gas pipe. The ambient temperature gas pipe is connected to the kiln tail hood of the rotary heating furnace, and the heating gas pipe is connected to the kiln head hood of the rotary heating furnace.

[0010] The storage bin is located at the bottom of the kiln tail hood of the rotary cooling furnace, and the discharge valve is located at the bottom of the storage bin. The discharge valve is connected to the kiln head hood of the rotary heating furnace through a high-temperature feeder. The bottom of the kiln tail hood of the rotary heating furnace is connected to the feeding end of the elevator through a feeder, and the discharging end of the elevator is connected to the kiln head hood of the rotary cooling furnace.

[0011] Furthermore, the bracket of the rotary cooling furnace is fixed on the support platform, the support platform is fixed on the ground, and the bracket of the rotary heating furnace is fixed on the ground.

[0012] Furthermore, the support platform is a steel structure bracket, the bracket is a steel structure or reinforced concrete structure, and the support rollers are steel rotating wheels.

[0013] Furthermore, the furnace body is a steel cylindrical furnace body, and a refractory insulation layer is installed on the inner wall of the furnace body, with a thickness of 50~300mm.

[0014] Furthermore, the kiln tail hood and kiln head hood are steel structure sealed covers, and mechanical seals are provided for the connection gaps between the kiln tail hood, kiln head hood and both ends of the furnace body. The inner walls of the kiln tail hood and kiln head hood are provided with refractory insulation layers with a thickness of not less than 50mm.

[0015] Furthermore, the heat storage body is in the form of spherical particles, with a maximum particle diameter not exceeding 30 mm.

[0016] Furthermore, the high-temperature flue gas pipe, cooling flue gas pipe, normal temperature gas pipe, and heating gas pipe are all steel structure pipes. The high-temperature flue gas pipe and heating gas pipe are equipped with a fire-resistant insulation layer with a thickness of 50~200mm.

[0017] Furthermore, the storage silo is a steel structure silo with a volume of not less than 5m³. 3 The unloading valve is a high-temperature resistant steel structure unloading valve.

[0018] Furthermore, the elevator is a bucket elevator; the dust collector is a bag filter dust collector; the induced draft fan is a variable frequency fan; and the chimney is a steel structure chimney.

[0019] Beneficial Effects: This system achieves highly efficient waste heat utilization of high-temperature flue gas. It innovatively develops a rotary cooling furnace and a rotary heating furnace, utilizing the recycled heat storage medium as a solid heat exchange medium to cool the high-temperature flue gas and efficiently transfer its heat to the heating of the required gas, maximizing the utilization of high-temperature flue gas waste heat. The system boasts advantages such as simple process equipment, stable and reliable operation, easy operation, low system failure rate, low investment, small footprint, and high production efficiency. my country has numerous industrial kilns in industries such as metallurgy and building materials, generating a huge amount of high-temperature flue gas, indicating a vast market application potential for this invention. Compared to traditional waste heat utilization boilers, it has significant technological and market advantages. It can not only be used for flue gas emission treatment in industrial kilns such as metallurgy, but also provide reliable process equipment support for the utilization of combustion waste gas from waste incineration and coal-fired boilers, demonstrating outstanding commercial value. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the waste heat utilization system for a high-temperature flue gas rotary kiln.

[0021] In the diagram: 1-High-temperature flue gas pipe, 2-Rotary cooling furnace, 3-Rotary heating furnace, 4-Floor, 5-Support platform, 6-Bracket, 7-Roller, 8-Furnace body, 9-Kiln tail hood, 10-Kiln head hood, 11-Lifting plate, 12-Heat regenerator, 13-Storage bin, 14-Discharge valve, 15-High-temperature feeder, 16-Feeder, 17-Elevator, 18-Cooling flue gas pipe, 19-Dust collector, 20-Induced draft fan, 21-Chimney, 22-Ambient temperature gas pipe, 23-Heating gas pipe. Detailed Implementation

[0022] The present invention will be further explained below with reference to the accompanying drawings.

[0023] like Figure 1As shown, a high-temperature flue gas rotary kiln waste heat utilization system includes a high-temperature flue gas pipe 1, a rotary cooling furnace 2, a rotary heating furnace 3, a heat storage body 12, a material storage bin 13, a discharge valve 14, a high-temperature feeder 15, a feeder 16, an elevator 17, a cooling flue gas pipe 18, a dust collector 19, an induced draft fan 20, a chimney 21, a normal temperature gas pipe 22, and a heating gas pipe 23.

[0024] Both the rotary cooling furnace 2 and the rotary heating furnace 3 include a bracket 6, a support roller 7, a furnace body 8, a kiln tail hood 9, a kiln head hood 10, and a lifting plate 11. The furnace body 8 is supported on the support roller 7, and the support roller 7 is fixed on the bracket. A heat storage body 12 is installed inside the furnace body 8. The kiln tail hood 9 and the kiln head hood 10 are distributed at both ends of the furnace body 8, and the lifting plate 11 is installed on the inner wall of the furnace body 8.

[0025] To facilitate the transport of the heat storage body 12, the rotary cooling furnace 2 and the rotary heating furnace 3 are arranged one above the other. The bracket 6 of the rotary cooling furnace 2 is fixed on the support platform 5, the support platform 5 is fixed on the ground 4, and the bracket 6 of the rotary cooling furnace 2 is fixed on the ground 4.

[0026] In this embodiment, the support platform 5 is a steel structure bracket, the bracket 6 is a steel or reinforced concrete structure, and the support roller 7 is a steel rotating wheel. The furnace body 8 is a steel cylindrical furnace body, and the inner wall of the furnace body 8 is provided with a refractory insulation layer with a thickness of 50~300mm. The kiln tail hood 9 and the kiln head hood 10 are steel structure sealed covers. The connection gap between the kiln tail hood 9, the kiln head hood 10 and the two ends of the furnace body 8 is provided with a mechanical seal. The sealing method is preferably a scale-type or labyrinth-type seal. The inner wall of the kiln tail hood 9 and the kiln head hood 10 is provided with a refractory insulation layer with a thickness of not less than 50mm. The lifting plate 11 is a lifting plate made of refractory material. The lifting plate 11 and the refractory insulation layer of the inner wall of the furnace body 8 are connected and fixed by masonry with high-temperature resistant material. The heat storage body 12 is spherical granular, with a maximum particle diameter of not more than 30mm, and is preferably made of alumina or iron oxide-based materials.

[0027] The high-temperature flue gas pipe 1 is connected to the kiln tail hood 9 of the rotary cooling furnace 2. The kiln head hood 10 of the rotary cooling furnace 2 is connected to the dust collector 19, the induced draft fan 20, and the chimney 21 in sequence through the cooling flue gas pipe 18. The ambient temperature gas pipe 22 is connected to the kiln tail hood 9 of the rotary heating furnace 3. The heating gas pipe 23 is connected to the kiln head hood 10 of the rotary heating furnace 3. The above connections are made by welding or bolt fixing.

[0028] In this embodiment, the high-temperature flue gas pipe 1, the cooling flue gas pipe 18, the ambient temperature gas pipe 22, and the heating gas pipe 23 are all steel structure pipes. The high-temperature flue gas pipe 1 and the heating gas pipe 23 are equipped with a fire-resistant insulation layer with a thickness of 50~200mm. The dust collector 19 is a bag filter dust collector, the induced draft fan 20 is a variable frequency fan, and the chimney 21 is a steel structure chimney.

[0029] The storage bin 13 is located at the bottom of the kiln tail hood 9 of the rotary cooling furnace 2. The discharge valve 14 is located at the bottom of the storage bin 13. The discharge valve 14 is connected to the kiln head hood 10 of the rotary heating furnace 3 through the high-temperature feeder 15. The bottom of the kiln tail hood 9 of the rotary heating furnace 3 is connected to the feeding end of the elevator 17 through the feeder 16. The discharging end of the elevator 17 is connected to the kiln head hood 10 of the rotary cooling furnace 2. The above connection methods are fixed by welding or bolts.

[0030] In this embodiment, the storage silo 13 is a steel structure silo with a volume of not less than 5m³. 3 The unloading valve 14 is a high-temperature resistant steel structure unloading valve. The steel used for the unloading valve 14 and the high-temperature feeder 15 has a heat resistance temperature of not less than 500℃. The feeder 16 can meet the requirements for long-term stable operation at a temperature not lower than 200℃. The elevator 17 is a bucket elevator.

[0031] The working process of this high-temperature flue gas rotary furnace waste heat utilization system includes the following steps:

[0032] 1) High-temperature flue gas enters through the high-temperature flue gas pipe 1 and passes through the outside of the kiln tail hood 9 of the rotary cooling furnace 2. After being lifted by the elevator 17, the heat storage body 12 enters through the outside of the kiln head hood 10 of the rotary cooling furnace 2. The high-temperature flue gas rises from the kiln tail hood 9 to the kiln head hood 10, and the heat storage body 12 moves down from the kiln head hood 10 to the kiln tail hood 9 as the furnace body 8 of the rotary cooling furnace 2 rotates.

[0033] 2) The high-temperature flue gas and the heat storage body 12 undergo intense heat exchange under the stirring action of the lifting plates 11 in the rotary cooling furnace 2. After heat exchange, the high-temperature flue gas is cooled to a certain temperature and is discharged sequentially through the cooling flue gas pipe 18, dust collector 19, induced draft fan 20, and chimney 21. The heat storage body 12 gradually heats up during its downward movement in the rotary cooling furnace 2, falls into the storage bin 13, and is then uniformly and stably conveyed to the rotary heating furnace 3 through the unloading valve 14 and the first feeder 15.

[0034] 3) The heat storage body 12, heated by the high-temperature flue gas, enters the furnace body 8 through the kiln head hood 10 of the rotary furnace 3, and descends from the kiln head hood 10 to the kiln tail hood 9 as the furnace body 8 rotates. Ambient temperature gas is introduced from the side of the kiln tail hood 9 of the rotary furnace 3 through the ambient temperature gas pipe 22 and ascends towards the kiln head hood 10.

[0035] 4) The ambient temperature gas and the heat storage body 12 undergo intense heat exchange under the stirring action of the lifting plate 11 inside the rotary heating furnace 3. After heat exchange, the ambient temperature gas is heated to a certain temperature and then sent out for use through the heating gas pipe 23. The heat storage body 12 gradually cools down as it descends inside the rotary heating furnace 3, falls into the feeder 16, and is then lifted by the elevator 17 to the rotary cooling furnace 2 for recycling.

[0036] 5) Following steps 1) to 4), the rotary cooling furnace 2 cools the high-temperature flue gas and meets the temperature requirements of the bag filter, achieving ultra-clean emissions. Simultaneously, it heats the heat storage medium 12, providing a stable heat source for the subsequent rotary heating furnace 3 to heat ambient-temperature gas. The heated gas can be externally supplied for reuse. The heat storage medium 12 is recycled within the rotary cooling furnace 2 and rotary heating furnace 3, realizing the utilization of waste heat from the high-temperature flue gas and ultra-clean emissions.

[0037] The high-temperature flue gas entering the rotary cooling furnace 2 has an initial temperature of 500~1600℃, and after passing through the rotary cooling furnace 2, its exhaust temperature through the cooling flue gas pipe 18 does not exceed 200℃. The ambient temperature gas, after being heated by the rotary heating furnace 3, is exhausted through the heating gas pipe 23 at a temperature not lower than 400℃. The heat regenerator 12, after being heated by the rotary cooling furnace 2, falls from the kiln tail hood 9 of the rotary cooling furnace 2 at a temperature not lower than 400℃. After being cooled by the rotary heating furnace 3, the heat regenerator 12 falls from the kiln tail hood 9 of the rotary heating furnace 3 at a temperature not exceeding 200℃. The residence time of the heat regenerator 12 in both the rotary cooling furnace 2 and the rotary heating furnace 3 is 20~60 minutes, and the heat exchange cycle of the entire system is 50~130 minutes. The inclination angle of the rotary cooling furnace 2 and the rotary heating furnace 3 is 0.5~3%, and the rotation speed is 0.5~5 revolutions per minute.

[0038] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A waste heat utilization system for a high-temperature flue gas rotary furnace, characterized in that: Includes high-temperature flue gas pipe (1), rotary cooling furnace (2), rotary heating furnace (3), heat storage body (12), storage bin (13), unloading valve (14), high-temperature feeder (15), feeder (16), elevator (17), cooling flue gas pipe (18), dust collector (19), induced draft fan (20), chimney (21), ambient temperature gas pipe (22), heating gas pipe (23); The rotary cooling furnace (2) and the rotary heating furnace (3) both include a bracket (6), a support roller (7), a furnace body (8), a kiln tail hood (9), a kiln head hood (10), and a lifting plate (11). The furnace body (8) is supported on the support roller (7), and the support roller (7) is fixed on the bracket. A heat storage body (12) is installed inside the furnace body (8). The kiln tail hood (9) and the kiln head hood (10) are distributed at both ends of the furnace body (8), and the lifting plate (11) is installed on the inner wall of the furnace body (8). The high-temperature flue gas pipe (1) is connected to the kiln tail hood (9) of the rotary cooling furnace (2). The kiln head hood (10) of the rotary cooling furnace (2) is connected to the dust collector (19), the induced draft fan (20), and the chimney (21) in sequence through the cooling flue gas pipe (18). The ambient temperature gas pipe (22) is connected to the kiln tail hood (9) of the rotary heating furnace (3). The heating gas pipe (23) is connected to the kiln head hood (10) of the rotary heating furnace (3). The storage bin (13) is located at the bottom of the kiln tail cover (9) of the rotary cooling furnace (2), and the discharge valve (14) is located at the bottom of the storage bin (13). The discharge valve (14) is connected to the kiln head cover (10) of the rotary heating furnace (3) through the high temperature feeder (15). The bottom of the kiln tail cover (9) of the rotary heating furnace (3) is connected to the feeding end of the elevator (17) through the feeder (16). The discharging end of the elevator (17) is connected to the kiln head cover (10) of the rotary cooling furnace (2).

2. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The bracket (6) of the rotary cooling furnace (2) is fixed on the support platform (5), the support platform (5) is fixed on the ground (4), and the bracket (6) of the rotary heating furnace (3) is fixed on the ground (4).

3. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 2, characterized in that: The support platform (5) is a steel structure bracket, the bracket (6) is a steel structure or reinforced concrete structure, and the support roller (7) is a steel rotating wheel.

4. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The furnace body (8) is a steel cylindrical furnace body, and a fire-resistant insulation layer is installed on the inner wall of the furnace body (8), with a thickness of 50~300mm.

5. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The kiln tail cover (9) and kiln head cover (10) are steel structure sealed covers. The connection gap between the kiln tail cover (9), kiln head cover (10) and the furnace body (8) is provided with mechanical seal. The inner wall of the kiln tail cover (9) and kiln head cover (10) is provided with a refractory insulation layer with a thickness of not less than 50mm.

6. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The heat storage body (12) is in the form of spherical particles with a maximum particle diameter of no more than 30 mm.

7. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The high-temperature flue gas pipe (1), cooling flue gas pipe (18), normal temperature gas pipe (22), and heating gas pipe (23) are all steel structure pipes. The high-temperature flue gas pipe (1) and heating gas pipe (23) are equipped with a fire-resistant insulation layer with a thickness of 50~200mm.

8. The high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The storage silo (13) is a steel structure silo with a volume of not less than 5m³. 3 The unloading valve (14) is a steel structure high temperature resistant unloading valve.

9. A high-temperature flue gas rotary furnace waste heat utilization system according to claim 1, characterized in that: The elevator (17) is a bucket elevator; the dust collector (19) is a bag filter; the induced draft fan (20) is a variable frequency fan; and the chimney (21) is a steel structure chimney.

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