Recycling system for exhausted and compressed air of hot blast stove

Abstract

According to the hot blast stove exhaust pressure gas recycling system provided by the invention, the exhaust pressure gas is exhausted to the air heat exchanger, so that the heat of the exhaust pressure gas can be utilized, and the utilization rate of energy is improved. The system comprises a plurality of hot blast stoves, a combustion-supporting air pipeline and an air heat exchanger, each hot blast stove is provided with a flue gas pipeline, and each flue gas pipeline is divided into a first sub-pipe and a second sub-pipe; the air heat exchanger is provided with a flue gas channel and a combustion-supporting gas channel, an inlet of the combustion-supporting gas channel is communicated with the combustion-supporting air pipeline, and gas located in the combustion-supporting gas channel can exchange heat with flue gas in the flue gas channel; the first sub-pipe can be communicated with or disconnected from an inlet of the smoke channel, and the second sub-pipe can be directly communicated with or disconnected from an inlet of the combustion-supporting gas channel.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace ironmaking in the metallurgical industry, and in particular to a hot blast furnace exhaust compressed air recovery and utilization system. Background Art

[0002] As an important equipment in industrial production, hot blast furnace is widely used in many fields such as steel, non-ferrous metal smelting, glass manufacturing, etc. Its main function is to generate high-temperature hot air through combustion-heat storage-heat exchange to provide necessary heat energy for the production process. The production process of hot blast furnace is usually divided into two stages: "combustion" and "air supply". In the "combustion" stage, the fuel and combustion air are fully burned in the hot blast furnace, releasing a large amount of heat energy; in the "air supply" stage, the cold air is sent into the hot blast furnace by the blower, and after heating, it forms high-temperature hot air for production use.

[0003] However, when the hot blast furnace switches from the "air supply" stage to the "combustion" stage, the pressure in the furnace needs to be adjusted to meet the needs of the combustion process, so a pressure relief operation must be performed. During the pressure relief operation, a furnace of high-temperature and high-pressure air and oxygen mixture will be discharged. In traditional processes, this part of the air and oxygen mixture is regarded as "waste gas" and directly discharged into the chimney. This method causes a huge waste of energy. Summary of the invention

[0004] The purpose of the present invention is to provide a hot blast furnace exhaust gas recovery and utilization system, which can utilize the heat of the exhaust gas by discharging the exhaust gas to the combustion gas channel of the air heat exchanger, thereby improving the utilization rate of energy.

[0005] To achieve the above object, the present invention provides a hot blast stove exhaust gas recovery and utilization system, the system comprises a plurality of hot blast stoves, a combustion-supporting air duct and an air heat exchanger, each of the hot blast stoves is provided with a flue gas duct, and each of the flue gas ducts is divided into a first sub-duct and a second sub-duct;

[0006] The air heat exchanger has a flue gas channel and a combustion-supporting gas channel, the combustion-supporting gas channel is connected to the combustion-supporting air pipeline, and the gas in the combustion-supporting gas channel can exchange heat with the flue gas in the flue gas channel;

[0007] The first sub-tube can be connected to or disconnected from the inlet of the smoke channel, and the second sub-tube can be directly connected to or disconnected from the inlet of the combustion-supporting gas channel.

[0008] By adopting the technical solution of the present application, the exhaust gas of the hot blast furnace is transported to the combustion-supporting gas channel of the air heat exchanger through the second sub-pipe, thereby merging the exhaust gas into the combustion-supporting gas, and the heat of the exhaust gas is utilized to increase the temperature of the combustion-supporting gas entering the combustion-supporting gas channel, thereby improving the energy utilization rate.

[0009] Optionally, the first sub-pipe is provided with a first valve, the second sub-pipe is provided with a second valve, and one of the first valve and the second valve is in an open position, and the other is in a closed position.

[0010] The connection and disconnection states of the first sub-pipe and the second sub-pipe are controlled by setting the first valve and the second valve to match different working conditions of each hot blast stove.

[0011] Optionally, it also includes an exhaust gas main pipe, and the outlets of the second sub-pipes of each of the hot blast furnaces are connected to the exhaust gas main pipe, and are indirectly connected to the inlet of the combustion-supporting gas channel through the exhaust gas main pipe.

[0012] Therefore, by setting up the exhaust and pressure gas main pipe, the integration of the pipeline is improved and the pipeline layout is simplified.

[0013] Optionally, the exhaust gas main pipe includes a first pipe section and a second pipe section distributed in sequence along the exhaust gas flow direction, and each of the second sub-pipes is connected to the first pipe section; the radial dimension of the second pipe section is larger than the radial dimension of the second sub-pipe and larger than the radial dimension of the first pipe section.

[0014] By adopting an exhaust gas main pipe with a variable diameter structure, the pressure of the exhaust gas in the rear section of the exhaust gas main pipe is reduced, thereby preventing the high-pressure exhaust gas from directly entering the air heat exchanger and causing impact on the air heat exchanger.

[0015] Optionally, the air heat exchanger includes an outer shell, a plurality of pipe portions are arranged in the inner shell, and each of the pipe portions surrounds the flue gas channel; the outer shell is provided with an air intake structure, and the air intake structure is used to communicate with the combustion-supporting gas channel; the air intake structure is a truncated cone structure, and the inlet of the combustion-supporting air duct is connected to the table surface of the truncated cone structure.

[0016] By providing an air intake structure with a truncated cone structure, the combustion-supporting air pipeline can be connected to the air heat exchanger.

[0017] Optionally, the tail end of the exhaust and compressed air main pipe has a third pipe section, and the third pipe section is distributed around the side wall of the frustum structure. The third pipe section is also connected to a plurality of third sub-pipes, and the third sub-pipes extend radially along the frustum structure and pass through the side wall of the frustum structure.

[0018] By providing the third pipe section, the third sub-pipe can be connected to the side wall of the truncated cone structure. At the same time, the third pipe section also plays a function of further reducing the pressure.

[0019] Optionally, the third pipe section is arranged in a partial or complete annular layout. By arranging the partial or complete annular layout, the gas entering the air heat exchanger can be further pressurized.

[0020] Optionally, the third pipe section is in a spiral structure, extending in a spiral shape along the central axis of the truncated cone structure and around the outer side of the truncated cone structure. The third pipe section in a spiral structure can further evenly pressurize the gas entering the air heat exchanger.

[0021] Optionally, the plurality of third sub-tubes are evenly distributed along the circumferential direction, thereby enabling uniform air intake along the circumferential direction, thereby further avoiding the impact of the exhaust gas on the air heat exchanger.

[0022] Optionally, the radial dimension of the third pipe section is consistent with the radial dimension of the second pipe section and is larger than the radial dimension of the third sub-pipe, thereby reducing the flow rate and flow of the exhaust gas entering the truncated cone structure, further avoiding impact on the air heat exchanger.

[0023] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0025] Figure 1 2 is a schematic structural diagram of a hot blast furnace exhaust compressed air recovery and utilization system according to an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 Schematic diagram of some structures;

[0027] Figure 3 It is a schematic diagram of the structure of the air heat exchanger, front view;

[0028] Figure 4 yes Figure 3 Side view of.

[0029] Reference numerals:

[0030] 100-hot blast furnace; 101-flue gas duct; 101-1a-first sub-pipe; 101-1b-first valve; 101-2a-second sub-pipe; 101-2b-second valve; 200-combustion-supporting air duct; 300-air heat exchanger; 301-housing; 302-pipe section; 303-air intake structure; 304-flue gas channel; 305-combustion-supporting gas channel; 400-exhaust and pressure gas main pipe; 401-first pipe section; 402-second pipe section; 403-third pipe section. DETAILED DESCRIPTION

[0031] The present invention provides a method for effectively recycling the heat energy in a mixture of high-temperature and high-pressure air and oxygen generated in a hot blast furnace depressurization process, thereby improving the utilization rate of energy.

[0032] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] Relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0034] As an important equipment in industrial production, hot blast furnace is widely used in many fields such as steel, non-ferrous metal smelting, glass manufacturing, etc. Its main function is to generate high-temperature hot air through combustion-heat storage-heat exchange to provide necessary heat energy for the production process. The production process of hot blast furnace is usually divided into two stages: "combustion" and "air supply". In the "combustion" stage, the fuel and combustion air are fully burned in the hot blast furnace, releasing a large amount of heat energy; in the "air supply" stage, the cold air is sent into the hot blast furnace by the blower, and after heating, it forms high-temperature hot air for production use.

[0035] However, during the transition from the "air supply" stage to the "combustion" stage of the hot blast stove, the pressure in the stove needs to be adjusted to meet the needs of the combustion process, so a pressure relief operation must be performed. During the pressure relief operation, a high-temperature and high-pressure air and oxygen mixture will be discharged. In traditional processes, this part of the air and oxygen mixture is regarded as "waste gas" and discharged directly into the chimney.

[0036] However, the high-temperature and high-pressure mixture of air and oxygen contains a large amount of heat energy. Direct emission not only causes a huge waste of energy, but also increases the energy consumption cost of the enterprise. In addition, the high-energy consumption and high-emission production method no longer meets the current environmental protection requirements.

[0037] Specifically, taking a 2000-class blast furnace as an example, if three top-fired hot blast furnaces are configured and the air supply time is 45 minutes, then the number of times the three hot blast furnaces are replaced and discharged in one day (24 hours) is 24×60 / 45=32 times. Assuming that the net volume of each hot blast furnace is 1000m3, the average temperature of the discharged gas is 500℃, and the air supply pressure is 0.45MPa. The specific heat capacity of air is about 1.000KJ / kg.℃, and the density of air is: ρ=((0.45+0.1) / 0.1)×1.29=7.095kg / Nm3. The heat required to heat a furnace gas to 300℃ (because the cold air temperature is about 200℃) is Q=1.000×7.095×1000×300=2.13×106KJ. In one year (350 days), the heat emitted by the hot blast furnace replacement of a 2000-class blast furnace is about = 2.13×106×32×350=2.39×1010KJ. The low calorific value of standard coal is 2930KJ / Kg, so the heat emitted by the hot blast furnace replacement in one year is equivalent to the weight of standard coal = 2.39×1010 / 2930=8156 tons. Assuming that the price of coal is 800 yuan per ton, the energy wasted by the hot blast furnace replacement in one year is equivalent to RMB: 8156×0.08=6.525 million.

[0038] In another example, the internal pressure equalization operation between multiple hot blast stoves is used as an example. Taking four hot blast stoves as an example, assuming that when the exhaust pressure gas of hot blast stove No. 1 needs to be utilized, it can be considered to be discharged into hot blast stove No. 2 which needs pressure equalization. This operation is intended to achieve pressure balance between the two hot blast stoves by utilizing the high-temperature and high-pressure gas discharged from hot blast stove No. 1 to provide additional pressure and heat for hot blast stove No. 2. However, when the pressures of the two hot blast stoves reach a balanced state, the pressure equalization operation can be stopped, and cold air can be used to further pressure equalize hot blast stove No. 2. However, it is worth noting that in this pressure equalization process, the remaining exhaust pressure gas of hot blast stove No. 1 is still discharged to the chimney as waste gas, which also causes a large waste of energy.

[0039] Please refer to Figures 1 to 4 , Figure 1 2 is a schematic structural diagram of a hot blast furnace exhaust compressed air recovery and utilization system according to an embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of some structures; Figure 3 It is a schematic diagram of the structure of the air heat exchanger, front view; Figure 4 yes Figure 3 Side view of.

[0040] The hot blast furnace 100 exhaust gas recovery and utilization system comprises a plurality of hot blast furnaces 100, a combustion-supporting air duct 200 and an air heat exchanger 300. Each hot blast furnace 100 is provided with a flue gas duct 101, and each flue gas duct 101 is divided into a first sub-duct 101-1a and a second sub-duct 101-2a.

[0041] The air heat exchanger 300 has a flue gas channel 304 and a combustion-supporting gas channel 305. The combustion-supporting gas channel 305 is connected to the combustion-supporting air pipeline 200. The gas in the combustion-supporting gas channel 305 can exchange heat with the flue gas in the flue gas channel 304. At least one of the plurality of hot blast stoves 100 is in a combustion condition, at least one is in a ventilating condition, and at least one is in a pressure exhaust condition. The first sub-tube 101-1a can be connected or disconnected with the inlet of the flue gas channel 304, and the second sub-tube 101-2a can be directly connected or disconnected with the inlet of the combustion-supporting gas channel 305. The first sub-tube 101-1a is provided with a first valve 101-1b, and the second sub-tube 101-2a is provided with a second valve 101-2b. One of the first valve 101-1b and the second valve 101-2b is in an open position, and the other is in a closed position. Specifically, in the hot blast stove 100 in the combustion state, the first valve 101-1b is in the open position, and the second valve 101-2b is in the closed position. In the hot blast stove 100 in the pressure relief state, the first valve 101-1b is in the closed position, and the second valve 101-2b is in the open position. By setting the first valve 101-1b and the second valve 101-2b, the connection and disconnection states of the first sub-pipe 101-1a and the second sub-pipe 101-2a are controlled to match the different working conditions of each hot blast stove 100.

[0042] In the technical solution of the present application, by adopting the technical solution of the present application, the exhaust gas of the hot blast furnace 100 is transported to the combustion-supporting gas channel 305 of the air heat exchanger 300 through the second sub-pipe 101-2a, so that the exhaust gas is merged into the combustion-supporting gas, and the heat of the exhaust gas is utilized to increase the temperature of the combustion-supporting gas entering the combustion-supporting gas channel 305, thereby improving the energy utilization rate.

[0043] In some optional examples, the exhaust gas recovery and utilization system of the hot blast stove 100 further includes an exhaust gas main pipe 400, and the outlets of the second sub-pipes 101-2a of each hot blast stove 100 can be connected to the exhaust gas main pipe 400, and indirectly connected to the inlet of the combustion-supporting gas channel 305 through the exhaust gas main pipe 400. After the second valve 101-2b is opened, the second sub-pipe 101-2a corresponding to the hot blast stove 100 can transport the high-temperature and high-pressure gas in the hot blast stove 100 to the exhaust gas main pipe 400. Thus, by setting the exhaust gas main pipe 400, the integration of the pipeline is improved and the pipeline layout is simplified.

[0044] In a specific example, the exhaust gas main pipe 400 includes a first pipe section 401 and a second pipe section 402 which are sequentially distributed along the exhaust gas flow direction. Compared with the second pipe section 402, the first pipe section 401 is farther away from the side where the air heat exchanger 300 is located. Each second sub-pipe 101-2a is connected to the first pipe section 401. The radial dimension of the second pipe section 402 is larger than the radial dimension of the second sub-pipe 101-2a and larger than the radial dimension of the first pipe section 401. In a specific example, the diameter of the second sub-pipe 101-2a is 400 mm, and the radial dimension of the exhaust gas main pipe 400 is 600 mm, which can of course be other radial dimension ranges.

[0045] As an optional example, the ratio of the radial dimension of the exhaust and compressed air main pipe 400 to the radial dimension of the second sub-pipe 101-2a is greater than or equal to 3:2. By adopting the exhaust and compressed air main pipe 400 with a variable diameter structure, the pressure of the exhaust and compressed air in the rear section of the exhaust and compressed air main pipe 400 is reduced, and the high-pressure exhaust and compressed air is prevented from directly entering the air heat exchanger 300 and causing an impact on the air heat exchanger 300.

[0046] In some other embodiments of the present application, the air heat exchanger 300 includes a housing 301, and a plurality of pipes 302 are disposed in the housing 301. The pipes 302 extend along a first direction. Figure 3 In the left-right direction, the pipes 302 extend from left to right, and the smoke passages 304 are surrounded by each other. In the smoke passages 304, the smoke flows from left to right. Figure 4 In the example shown, the flue gas flows in a direction perpendicular to the paper surface. A combustion-supporting gas channel 305 is defined between each pipe portion 302 and the shell 301. The shell 301 is provided with an air inlet and an air outlet as a combustion-supporting gas inlet and a combustion-supporting gas outlet of the combustion-supporting gas channel 305. In an optional example, the combustion-supporting gas inlet and the combustion-supporting gas outlet are located on the same side of the shell 301, thereby facilitating the layout of the air heat exchanger 300.

[0047] The housing 301 is provided with an air intake structure 303, which is used to communicate with the combustion-supporting gas channel 305; the air intake structure 303 is a truncated cone structure, and the inlet of the combustion-supporting air duct 200 is connected to the table surface of the truncated cone structure. The cross section of the truncated cone structure in the axial direction can be rectangular or trapezoidal. If the cross section of the truncated cone structure in the axial direction is a trapezoid, the small diameter end of the truncated cone structure is connected to the inlet of the combustion-supporting air duct 200, and the large diameter end is connected to the air inlet of the combustion-supporting gas channel 305. By providing the air intake structure 303 with a truncated cone structure, the combustion-supporting air duct 200 can be connected to the air heat exchanger 300.

[0048] In another embodiment, the tail end of the exhaust and compressed air main pipe 400 has a third pipe section 403, and the third pipe section 403 is connected to the second pipe section 402, and the radial dimensions of the two can be consistent or gradually increased, that is, the radial dimension of the third pipe section 403 can be consistent with the radial dimension of the second pipe section 402, or it can be larger than the radial dimension of the second pipe section 402.

[0049] The third pipe section 403 is distributed around the side wall of the truncated cone structure. In one example, the third pipe section 403 is arranged in a partial or complete annular shape, that is, the third pipe section 403 is distributed in a large semicircular arc, a small semicircular arc, a semicircular arc or a full circular arc shape. In another example, the third pipe section 403 is in a spiral structure, extending in a spiral shape around the outer side of the truncated cone structure along the central axis of the truncated cone structure.

[0050] The third pipe section 403 is also connected to a plurality of third sub-pipes, and the third sub-pipes extend along the radial direction of the truncated cone structure and pass through the side wall of the truncated cone structure.

[0051] By providing the third pipe section 403, the third sub-tube can be connected to the side wall of the truncated cone structure. At the same time, the third pipe section 403 also plays a function of further reducing the pressure.

[0052] Optionally, the plurality of third sub-tubes are evenly distributed along the circumferential direction, thereby enabling uniform air intake along the circumferential direction, thereby further avoiding the impact of the exhaust gas on the air heat exchanger 300 .

[0053] In the above embodiment, the radial dimension of the third pipe section 403 is consistent with the radial dimension of the second pipe section 402 and is larger than the radial dimension of the third sub-pipe, thereby reducing the flow rate and flow of the exhaust gas entering the truncated cone structure, further avoiding impact on the air heat exchanger 300.

[0054] In the aforementioned technical solution, the purpose of depressurization is to open the first valve 101-1b. The valve opening pressure difference of the first valve 101-1b is ~20KPa, and the pressure of the flue is about 0.5~0.8KPa during normal production. Therefore, when the second valve 101-2b is closed (the first valve 101-1b is opened), the pressure in the furnace is about 20.5~20.8KPa, and the pressure of the combustion air of the hot blast furnace 100 is 12.5KPa. Therefore, the exhaust gas can enter the air heat exchanger 300 during the entire depressurization process.

[0055] The following is an explanation with a specific embodiment. Taking a 2000-class blast furnace as an example, if three top-fired hot blast furnaces 100 are configured and the air supply time is 45 minutes, then the number of times the hot blast furnace 100 is replaced and discharged in one day (24 hours) is 24×60 / 45=32 times. If the net volume of each hot blast furnace 100 is 1000m3, the average temperature of the discharged gas is 500℃, and the air supply pressure is 0.45MPa. Using the ideal gas state equation, the air volume under standard state is: V2=P1V1T2 / P2T1=1769Nm3, and the air volume of the combustion-supporting fan configured for the 2000-level blast furnace hot blast stove 100 is generally about 150,000 Nm3 / h, equivalent to 2500Nm3 / min, and the exhaust time is generally controlled within 5 minutes. The exhaust gas flow rate is 1769 / 5=353Nm3 / min, 353 / 2500=14.12%. The combustion-supporting fan is frequency-controlled at the same time as the exhaust, and the outlet air volume is adjusted to 85%~90% of the original.

[0056] Compared with the prior art, the advantages of this application are:

[0057] First, by adopting the technical solution of the present application, the exhaust gas of the hot blast furnace 100 is transported to the combustion gas channel 305 of the air heat exchanger 300 through the second sub-pipe 101-2a, so that the exhaust gas is merged into the combustion gas, and the heat of the exhaust gas is utilized to increase the temperature of the combustion gas entering the combustion gas channel 305, thereby improving the energy utilization rate.

[0058] Second, by adopting the exhaust gas main pipe 400 with a variable diameter structure and a special-shaped structure, the pressure of the exhaust gas in the rear section of the exhaust gas main pipe 400 is reduced, thereby preventing the high-pressure exhaust gas from directly entering the air heat exchanger 300 and causing an impact on the air heat exchanger 300.

[0059] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A hot blast furnace exhaust compressed air recovery and utilization system, characterized in that: The invention comprises a plurality of hot blast furnaces (100), a combustion-supporting air duct (200) and an air heat exchanger (300), each of the hot blast furnaces (100) being provided with a flue gas duct (101), and each of the flue gas ducts (101) comprising a first sub-duct (101-1a) and a second sub-duct (101-2a); The air heat exchanger (300) comprises a smoke channel (304) and a combustion-supporting gas channel (305); the combustion-supporting gas channel (305) is connected to the combustion-supporting air pipeline (200); the gas in the combustion-supporting gas channel (305) can exchange heat with the smoke in the smoke channel (304); The first sub-tube (101-1a) can be connected to or disconnected from the inlet of the smoke channel (304), and the second sub-tube (101-2a) can be directly connected to or disconnected from the inlet of the combustion-supporting gas channel (305).

2. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 1, characterized in that: The first sub-tube (101-1a) is provided with a first valve (101-1b), and the second sub-tube (101-2a) is provided with a second valve (101-2b), and one of the first valve (101-1b) and the second valve (101-2b) is in an open position, and the other is in a closed position.

3. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 1, characterized in that: It also includes an exhaust gas main pipe (400), and the outlets of the second sub-tubes (101-2a) of each of the hot blast furnaces (100) are connected to the exhaust gas main pipe (400), and are indirectly connected to the inlet of the combustion-supporting gas channel (305) through the exhaust gas main pipe (400).

4. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 3, characterized in that: The exhaust gas main pipe (400) comprises a first pipe section (401) and a second pipe section (402) which are sequentially distributed along the exhaust gas flow direction, and each of the second sub-pipes (101-2a) is connected to the first pipe section (401); the radial dimension of the second pipe section (402) is larger than the radial dimension of the second sub-pipe (101-2a) and larger than the radial dimension of the first pipe section (401).

5. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 4, characterized in that: The air heat exchanger (300) comprises an outer shell (301), wherein a plurality of pipe sections (302) are arranged inside the outer shell (301), and each of the pipe sections (302) surrounds the flue gas channel (304); the outer shell (301) is provided with an air intake structure (303), and the air intake structure (303) is used to communicate with the combustion-supporting gas channel (305); the air intake structure (303) is a truncated cone structure, and the inlet of the combustion-supporting air pipeline (200) is connected to the table surface of the truncated cone structure.

6. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 5, characterized in that: A third pipe section (403) is provided at the tail end of the exhaust and compressed air main pipe (400), and the third pipe section (403) is distributed around the side wall of the truncated cone structure. The third pipe section (403) is also connected to a plurality of third sub-pipes, and the third sub-pipes extend along the radial direction of the truncated cone structure and pass through the side wall of the truncated cone structure.

7. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 6, characterized in that: The third pipe section (403) is a partial or complete annular structure.

8. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 6, characterized in that: The third pipe section (403) is in a spiral structure, extending in a spiral shape along the central axis of the truncated cone structure and around the outer side of the truncated cone structure.

9. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 6, characterized in that: The plurality of third sub-tubes are evenly distributed along the circumferential direction.

10. The hot blast furnace exhaust compressed air recovery and utilization system according to claim 6, characterized in that: The radial dimension of the third pipe section (403) is consistent with the radial dimension of the second pipe section (402), and is larger than the radial dimension of the third sub-pipe.

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