Flue gas utilization system of hot blast stove

Abstract

According to the flue gas utilization system of the hot blast stove, the flue gas of the hot blast stove is utilized, so that the situation that pulverization and pulverized coal conveying are affected when nitrogen in a factory is insufficient is avoided. The flue gas utilization system of the hot blast stove comprises a coal injection module used for pulverizing and conveying pulverized coal and a flue gas pipeline communicated with a flue at the tail of the hot blast stove, the coal injection module comprises a flue gas collecting piece and a pressurizing assembly, and the flue gas pipeline is directly or indirectly communicated with a first sub-pipe; the other end of the first sub-pipe is communicated with the flue gas collecting piece, and the first sub-pipe is further provided with the pressurizing assembly. The mode that nitrogen is used for the coal injection system is replaced by the process of pressurizing the flue gas exhausted by the hot blast stove, the energy utilization efficiency is improved, and the situation that the coal injection system is affected when the nitrogen is insufficient can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of hot blast stove technology, specifically to a hot blast stove flue gas utilization system. Background Technology

[0002] In steel production, the pulverized coal injection system is a crucial component, playing a vital role in improving the smelting efficiency of hot blast stoves and reducing production costs. During production, the pulverized coal injection system requires nitrogen as a carrier or protective gas to ensure the safety of the pulverizing system and the stable delivery of pulverized coal. However, in actual production, nitrogen usage is not arbitrarily adjustable; rather, it requires a balance between nitrogen supply and demand across the entire plant. In steel plant production practice, an imbalance between oxygen and nitrogen frequently occurs. This imbalance can stem from various factors, such as changes in production plans, reduced nitrogen production capacity due to equipment malfunctions, or fluctuations in oxygen and nitrogen consumption. When nitrogen is imbalanced, it can affect the normal operation of the pulverized coal injection system, leading to unstable pulverized coal delivery, decreased combustion efficiency, and even potentially causing safety accidents. Utility Model Content

[0003] The purpose of this invention is to provide a hot blast stove flue gas utilization system. By improving the structure of the hot blast stove flue gas utilization system, it is possible to avoid the situation where insufficient nitrogen affects pulverized coal injection.

[0004] To achieve the above objectives, this utility model provides a hot blast stove flue gas utilization system, including a pulverized coal injection module and a flue gas pipe connected to the tail flue of the hot blast stove. The pulverized coal injection module includes a flue gas collection component and a pressurization component. The flue gas pipe is directly or indirectly connected to a first sub-pipe. The other end of the first sub-pipe is connected to the flue gas collection component. The first sub-pipe is also provided with the pressurization component.

[0005] By adopting the technical solution in this application, and by using a process of pressurizing the flue gas discharged from the hot blast stove to replace nitrogen for the pulverized coal injection system, energy utilization efficiency is improved, and the situation of insufficient nitrogen affecting pulverized coal injection can be avoided.

[0006] Optionally, the flue gas duct is also connected to a heat exchanger. The first sub-tube is directly or indirectly connected to the flue gas duct at a location downstream of the heat exchanger in the flue gas flow direction. The heat exchanger in the flue gas duct allows for the recovery and utilization of heat from the flue gas. The first sub-tube's location downstream of the heat exchanger enables the use of the heat-exchanged flue gas to transport pulverized coal, avoiding the risks associated with using high-temperature flue gas for pulverized coal transport.

[0007] Optionally, the pressurization assembly includes a pressurizer and a filter. The filter is used to remove moisture from the flue gas, and the pressurizer is located between the flue gas collection unit and the filter. By setting up the pressurization assembly to pressurize the flue gas entering the flue gas collection unit, the storage of the flue gas is facilitated. In addition, before pressurization, the moisture in the flue gas is further removed, ensuring the dryness of the flue gas entering the pressurizer, avoiding damage to the pressurizer, and also preventing the water content in the flue gas used for pulverized coal injection from affecting the pulverized coal.

[0008] Optionally, the flue gas duct is further connected to a second sub-duct, the other end of which is connected to the heating furnace. The other end of the first sub-duct is connected to the second sub-duct and indirectly connected to the flue gas duct through the second sub-duct. The second sub-duct is used to transport the flue gas to the heating furnace for utilization. Connecting the first sub-duct to the second sub-duct integrates the first and second sub-ducts, improving the integration of the hot blast stove flue gas utilization system.

[0009] Optionally, the pulverized coal injection module further includes a first regulating valve, which is located on the first sub-pipe and upstream of the pressurization component in the direction of flue gas flow. By setting the first regulating valve, the amount of flue gas entering the pulverized coal injection module can be adjusted in real time according to the amount of flue gas required in the heating furnace, thereby avoiding any impact on the heating furnace. At the same time, the pulverized coal injection module also has a flue gas collection device, which can pre-store the pressurized flue gas to ensure the amount of flue gas required for pulverized coal injection, thereby ensuring the normal operation of both modules.

[0010] Optionally, the pulverized coal injection module further includes a first maintenance switch, which is located upstream of the first regulating valve. By setting the first maintenance switch, faults in the pipeline from the first regulating valve to the connection point between the first sub-pipe and the second sub-pipe can be eliminated.

[0011] Optionally, a second maintenance switch is also included, which is disposed between the first regulating valve and the pressurization assembly. By providing the second maintenance switch, faults in the pipeline from the first regulating valve to the connection between the first sub-pipe and the second sub-pipe, and between the pressurization assembly and the first regulating valve, can be eliminated.

[0012] Optionally, a third inspection switch is also included, located between the flue gas collection component and the pressurization assembly. By providing the third inspection switch, faults in the pipeline between the flue gas collection component and the pressurization assembly can be addressed.

[0013] Optionally, the second sub-pipe is further equipped with a flue gas induced draft fan, which is located upstream of the heating furnace, and the outlet of the flue gas induced draft fan is connected to the heating furnace. By providing a flue gas induced draft fan, flue gas can be blown into the heating furnace.

[0014] Optionally, it also includes a second regulating valve, which is located upstream of the flue gas induced draft fan;

[0015] The first sub-pipe is connected to the second sub-pipe and is located upstream of the second regulating valve. By setting the first regulating valve and the second regulating valve, the amount of flue gas entering the heating furnace and the amount of flue gas entering the pressurization assembly can be controlled.

[0016] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0018] Figure 1 This is a schematic diagram of the hot air furnace flue gas utilization system in an embodiment of this utility model.

[0019] Figure label:

[0020] 100-Pulverized coal injection module; 101-Flue gas collection component; 102-Pressure booster assembly; 102a-Pressure booster; 102b-Filter; 103-First regulating valve; 104-1-First maintenance switch; 104-2-Second maintenance switch; 104-3-Third maintenance switch; 105-First sub-pipe; 201-Second sub-pipe; 202-Heating furnace; 203-Flue gas induced draft fan; 204-Second regulating valve; 300-Flue gas duct; 301-Heat exchanger; 302-Chimney. Detailed Implementation

[0021] This invention provides a hot blast stove flue gas utilization system. By improving the structure of the hot blast stove flue gas utilization system, it is possible to avoid the situation where insufficient nitrogen affects pulverized coal injection.

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0024] Nitrogen is the primary transport gas in pulverized coal injection processes. Due to its stable chemical properties and good safety profile, nitrogen is an ideal choice for pulverizing and transporting coal gas. In addition to its transport function, nitrogen also serves as a protective gas. During pulverization and injection, pulverized coal readily reacts with oxygen in the air, leading to oxidation or even spontaneous combustion.

[0025] Nitrogen, as an inert gas, ensures the safety of pulverization and injection processes. The use of nitrogen not only concerns safety and stability but also directly affects pulverization efficiency. Due to its excellent fluidity and diffusivity, nitrogen ensures uniform distribution of pulverized coal within the blast furnace, thereby improving combustion efficiency and molten iron quality. The primary reason for choosing nitrogen is its inerting properties. However, the amount of nitrogen used in production needs to be balanced across the entire plant before being piped to the pulverization area. Steel plants frequently experience oxygen and nitrogen imbalances. To alleviate nitrogen shortages, this application proposes the following improvements.

[0026] like Figure 1 As shown, Figure 1 This is a schematic diagram of the hot air furnace flue gas utilization system in an embodiment of this utility model.

[0027] To achieve the above objectives, this utility model provides a hot blast stove flue gas utilization system, which includes a pulverized coal injection module 100 and a flue gas pipe 300 connected to the tail flue of the hot blast stove. The tail end of the flue gas pipe 300 is connected to a chimney 302 to discharge the flue gas.

[0028] The pulverized coal injection module 100 includes a flue gas collection component 101 and a pressurization component 102. The pressurization component 102 is used to pressurize the flue gas entering the flue gas collection component 101. The pressurization component 102 can use a physical pressurization method, which uses a compressor to compress the flue gas, thereby increasing its pressure; or it can use a chemical pressurization method, membrane separation pressurization, or magnetohydrodynamic pressurization, etc., which can be selected by those skilled in the art.

[0029] The flue gas duct 300 is directly or indirectly connected to a first sub-pipe 105. The other end of the first sub-pipe 105 is connected to a flue gas collection device 101 to transport the flue gas in the flue gas duct 300 to the flue gas collection device 101. The first sub-pipe 105 is also provided with a pressurization component 102.

[0030] In actual production, the flue gas from the flue gas duct 300 passes through the pressurization component 102 and then enters the flue gas collection component 101 through the first sub-pipe 105, thereby storing and reserving the flue gas.

[0031] The flue gas collection device 101 is adapted to a pulverized coal injection system (not shown in the figure). Specifically, the pulverized coal injection system includes a coal drop pipe (not shown in the figure) connected to a pulverized coal storage tank. The coal drop pipe is connected to the flue gas collection device 101, and the flue gas collection device 101 is connected to the coal drop pipe to transport the pulverized coal falling into the coal drop pipe to the blast furnace.

[0032] Specifically, the main components of the flue gas from the hot blast furnace are nitrogen and carbon dioxide, which can be approximated as inert gases. In the technical solution of this application, the flue gas is used as the gas for pulverization and injection.

[0033] In a more specific embodiment, the booster assembly 102 includes a booster compressor 102a and a filter 102b. The filter 102b is used to remove moisture from the flue gas, and the booster compressor 102a is located between the flue gas collection unit 101 and the filter 102b. The filter 102b is primarily responsible for removing moisture from the flue gas and can be a high-efficiency dehumidifying filter or a condenser dryer to ensure that the flue gas entering the booster compressor 102a is dry and pure.

[0034] By adopting the technical solution in this application, and by using a process of pressurizing the flue gas discharged from the hot blast stove to replace nitrogen for the pulverized coal injection system, energy utilization efficiency is improved.

[0035] Furthermore, by using the pressurization component 102 to pressurize the flue gas entering the flue gas collection component 101, the storage of the flue gas is facilitated. In addition, before pressurization, the moisture in the flue gas is further removed to ensure the dryness of the flue gas entering the pressurizer 102a, avoid damage to the pressurizer 102a, and also avoid the water content in the flue gas conveying pulverized coal from affecting the pulverized coal.

[0036] In the technical solution of this application, the flue gas duct 300 is also connected to a heat exchanger 301. The first sub-pipe 105 is directly or indirectly connected to the flue gas duct 300, located downstream of the heat exchanger 301 in the flue gas flow direction. After passing through the heat exchanger 301, the flue gas exchanges heat with the medium to be heated inside the heat exchanger 301, and the temperature of the flue gas decreases. The first sub-pipe 105 is located on the low-temperature side of the heat exchanger 301, thereby enabling further utilization of the flue gas discharged from the heat exchanger 301. The heat exchanger 301 can be a conventional type of heat exchanger 301.

[0037] A heat exchanger 301 is installed in the flue gas duct 300 to recover and utilize the heat in the flue gas. The first sub-pipe 105 is located downstream of the heat exchanger 301, so that the flue gas after heat exchange can be used to transport pulverized coal, avoiding the risks associated with using high-temperature flue gas to transport pulverized coal.

[0038] In the aforementioned embodiments, the flue gas duct 300 is also connected to a second sub-duct 201. The other end of the second sub-duct 201 is connected to the heating furnace 202, and the other end of the first sub-duct 105 is connected to the second sub-duct 201, and indirectly connected to the flue gas duct 300 through the second sub-duct 201. In this case, the flow rate of the second sub-duct 201 can be increased accordingly, or the flow velocity of the flue gas within the second sub-duct 201 can be increased. The second sub-duct 201 is used to transport the flue gas to the heating furnace 202 for utilization. Connecting the first sub-duct 105 to the second sub-duct 201 integrates the first sub-duct 105 and the second sub-duct 201, improving the integration of the hot blast furnace flue gas utilization system.

[0039] In some optional embodiments, the pulverized coal injection module 100 further includes a first regulating valve 103, which is disposed on the first sub-pipe 105 to regulate the flow rate and velocity of the flue gas in the first sub-pipe 105, and the first regulating valve 103 is disposed upstream of the booster assembly 102 in the flue gas flow direction.

[0040] By setting the first regulating valve 103, the amount of flue gas entering the pulverized coal injection module 100 can be adjusted in real time according to the amount of flue gas required in the heating furnace 202, thereby avoiding any impact on the heating furnace 202. At the same time, the pulverized coal conveying module 100 also has a flue gas collection component 101, which can pre-store the pressurized flue gas to ensure the amount of flue gas required for pulverized coal injection, thereby ensuring that both modules operate normally.

[0041] In this embodiment, the second sub-pipe 201 is further equipped with a flue gas induced draft fan 203, which is located upstream of the heating furnace 202, and its outlet is connected to the heating furnace 202. The flue gas induced draft fan 203 allows flue gas to be blown into the heating furnace 202. The second sub-pipe 201 is also equipped with a second regulating valve 204, located upstream of the flue gas induced draft fan 203. The first sub-pipe 105 connects to the second sub-pipe 201 and is located upstream of the second regulating valve 204. By setting the first regulating valve 103 and the second regulating valve 204, the amount of flue gas entering the heating furnace 202 and the amount of flue gas entering the pressurization assembly 102 can be controlled.

[0042] Specifically, taking a 60t pulverized coal injection system as an example, the total amount of nitrogen required under standard conditions is approximately 4000 Nm³ / h. Converted to the nitrogen volume V1 at room temperature and 1.2 MPa, it is: (12+1)V1 / (273+25) = 1 × 4000 / 273, therefore V1 = 336 m³. If this nitrogen is replaced by flue gas, the required flue gas volume is V2. Assuming a flue gas temperature of 140℃ and a flue gas pressure of 1 atmosphere, (12+1) × 336 / (273+25) = 1 × V2 / (273+140), therefore V2 = 6054 m³. The flue gas volume required by the pulverized coal injection system's heating furnace 202 is calculated to be 125534 m³, so 6048 / 125534 = 4.8%. The range of increase in pipe diameter or flow velocity for the second sub-pipe 201 can be calculated using the same method.

[0043] As an optional example, the pulverized coal injection module 100 also includes a first maintenance switch 104-1, which is located upstream of the first regulating valve 103. By setting the first maintenance switch 104-1, faults in the pipeline between the first regulating valve 103 and the point where the first sub-pipe 105 connects to the second sub-pipe 201 can be eliminated.

[0044] As another optional example, the pulverized coal conveying module 100 also includes a second maintenance switch 104-2, which is located between the first regulating valve 103 and the booster assembly 102. By setting the second maintenance switch 104-2, faults in the pipeline between the first regulating valve 103 and the connection between the first sub-pipe 105 and the second sub-pipe 201, and between the booster assembly 102 and the first regulating valve 103 can be eliminated.

[0045] As another optional example, the pulverized coal conveying module 100 also includes a third maintenance switch 104-3, which is located between the flue gas collection unit 101 and the pressurization assembly 102. By setting the third maintenance switch 104-3, faults in the pipeline between the flue gas collection unit 101 and the pressurization assembly 102 can be eliminated.

[0046] Compared with existing technologies, the advantages of this application are:

[0047] First, by using pressurized hot air furnace flue gas instead of nitrogen in the pulverized coal injection system, the nitrogen shortage problem has been effectively alleviated, and the gas source is safe and reliable.

[0048] Secondly, by integrating the first sub-pipe 105 and the second sub-pipe 201, it is only necessary to increase the flue gas flow rate of the second sub-pipe 201 or increase the pipe diameter of the second sub-pipe 201. The system structure is simple and the cost is low.

[0049] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A hot blast stove flue gas utilization system, characterized in that, It includes a pulverized coal injection module (100) and a flue gas duct (300) connected to the tail flue of the hot blast stove. The pulverized coal injection module (100) includes a flue gas collection component (101) and a pressurization component (102). The flue gas duct (300) is directly or indirectly connected to a first sub-pipe (105). The other end of the first sub-pipe (105) is connected to the flue gas collection component (101). The first sub-pipe (105) is also provided with the pressurization component (102).

2. The hot blast stove flue gas utilization system according to claim 1, characterized in that, The flue gas duct (300) is also connected to a heat exchanger (301). The first sub-tube (105) is directly or indirectly connected to the flue gas duct (300) at a location downstream of the heat exchanger (301) in the flue gas flow direction.

3. The hot blast stove flue gas utilization system according to claim 1, characterized in that, The booster assembly (102) includes a booster (102a) and a filter (102b) for removing moisture from the flue gas. The booster (102a) is located between the flue gas collector (101) and the filter (102b).

4. The hot blast stove flue gas utilization system according to claim 2, characterized in that, The flue gas duct (300) is also connected to a second sub-duct (201), the other end of which is connected to the heating furnace (202). The other end of the first sub-duct (105) is connected to the second sub-duct (201) and is indirectly connected to the flue gas duct (300) through the second sub-duct (201).

5. The hot blast stove flue gas utilization system according to claim 4, characterized in that, The pulverized coal injection module (100) also includes a first regulating valve (103), which is located on the first sub-pipe (105) and is positioned upstream of the booster assembly (102) in the direction of flue gas flow.

6. The hot blast stove flue gas utilization system according to claim 5, characterized in that, The pulverized coal injection module (100) also includes a first maintenance switch (104-1), which is located upstream of the first regulating valve (103).

7. The hot blast stove flue gas utilization system according to claim 5, characterized in that, It also includes a second maintenance switch (104-2), which is located between the first regulating valve (103) and the booster assembly (102).

8. The hot blast stove flue gas utilization system according to claim 5, characterized in that, It also includes a third maintenance switch (104-3), which is located between the flue gas collection component (101) and the pressurization component (102).

9. The hot blast stove flue gas utilization system according to claim 5, characterized in that, The second sub-pipe (201) is also equipped with a flue gas induced draft fan (203), which is located upstream of the heating furnace (202), and the outlet of the flue gas induced draft fan (203) is connected to the heating furnace (202).

10. The hot blast stove flue gas utilization system according to claim 9, characterized in that, It also includes a second regulating valve (204), which is located upstream of the flue gas induced draft fan (203); The first sub-pipe (105) is connected to the second sub-pipe (201) and is located upstream of the second regulating valve (204).

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