A pressure equalization system and method for full recovery of hot blast stove exhaust gas

Abstract

The present application belongs to the technical field of hot blast furnace, and discloses a kind of equalizing system and method of hot blast furnace waste gas full recovery, the present application utilizes circulating power module to fill the gas in storage tank in hot blast furnace and fills the gas in storage tank into hot blast furnace, not only can realize the recovery of all waste gas and pressure of hot blast furnace, improve heat utilization rate, simultaneously under the condition of not using blast furnace blower, utilize circulating power module to fill the recovered waste gas into hot blast furnace to equalize pressure, can reduce the temperature drop of hot blast furnace, improve heat utilization rate, and can maintain the stability of blast furnace blast, avoid the harm such as " tip " and " suspended material " of blast furnace due to hot blast furnace pressure charging, ensure the stability of blast furnace production, reduce blast furnace production energy consumption.

Description

[0001] This application is a divisional application of "A pressure equalization system and method for complete recovery of exhaust gas from a hot blast stove"; the original application date was June 30, 2022; the original application number was 202210771992.2; the original invention title was: A pressure equalization system and method for complete recovery of exhaust gas from a hot blast stove. Technical Field

[0002] This invention belongs to the technical field of blast furnace hot blast stoves, and particularly relates to a pressure equalization system and method for the complete recovery of waste gas from hot blast stoves. Background Technology

[0003] A blast furnace hot blast stove is a regenerative heat exchanger that operates periodically. Each blast furnace is typically equipped with 2 to 4 hot blast stoves (most blast furnaces have 3). Each hot blast stove goes through four working states in a working cycle: "combustion period" (heat storage), "shutdown period", "blast period" (heat release), and "shutdown period". Each hot blast stove cycles in this manner, and several hot blast stoves take turns switching states according to a certain pattern to ensure a continuous and stable supply of high-temperature blast to the blast furnace, thereby ensuring the safe, continuous, and stable production of the blast furnace.

[0004] When a hot blast stove switches between "combustion" and "air supply" states, the pressure of the medium inside the stove undergoes a transition from "atmospheric pressure" to "high pressure." This necessitates corresponding valve actions. These valve actions require either "pressure equalization" or "waste air release" operations. The "pressure equalization" operation is performed after the hot blast stove has finished combustion and entered a closed state, then transitions to air supply. During this operation, the cold air equalization valve is opened, and the pressure inside the hot blast stove gradually increases over time. When the pressure approaches the hot blast pressure, the pressure equalization operation is complete, and the hot blast stove then enters the air supply state, stably supplying air to the blast furnace. Currently, the most common method for pressurizing hot blast stoves is to blow air into the stove using a blast furnace blower. However, during pressurization, a small amount of air needs to be diverted from the blower for pressurization. Since the blower's pressure and volume are constant, this inevitably causes a drop in the blast furnace feed air pressure, leading to instability in the blast furnace.

[0005] After a certain period of blasting, the temperature at the top of the hot blast stove gradually decreases. If not switched back in time, the hot blast temperature will no longer meet the blast furnace's set requirements. At this point, the hot blast stove needs to be switched to combustion mode to bring the temperature back to the set requirements, preparing for the next blasting cycle. When switching from blasting to combustion, the hot blast stove needs to transition from high pressure to atmospheric pressure. This requires releasing waste air, i.e., depressurizing. The waste air valve is opened, releasing the pressurized and heated gas trapped inside the hot blast stove into the atmosphere as waste air. This waste air is generated by the blast furnace blower consuming energy (electricity or steam). It has a certain temperature and, more importantly, high pressure. Due to the large volume of the hot blast stove cavity and the frequent blasting cycles, the total amount of waste air released is considerable, resulting in energy waste. In order to recover as much of this energy as possible and save energy, and at the same time to ensure the stability of blast furnace blast and avoid the hazards of blast furnace "rising" and "suspended material" caused by hot blast stove pressurization, the following ideas were proposed and implemented.

[0006] In some steel plants operating four hot blast stoves, during stove switching, the waste air from the hot blast stoves that need to switch from blast to combustion is transported to the stoves switching from combustion to blast via connected pipes and valves, relying on pressure difference. However, after a period of operation, this system essentially ceases to function, failing to achieve its intended purpose. In summary, the main reasons are: 1) The operation of the hot blast stoves must conform to the operation of the blast furnace, and the blast furnace operation prioritizes stability; maintaining stable furnace conditions is the most effective way to save energy and reduce consumption. When using the current conventional waste air recovery system, the replacement of the hot blast stove means that the blast furnace's air supply status changes from two stoves to one. This will cause certain changes in the relationship between the blast furnace's air pressure and air volume, as well as instantaneous fluctuations in the air temperature. Because of this phenomenon, blast furnace operators are unwilling to maintain this operating mode for a long time. 2) Currently, most blast furnaces in the world are equipped with three hot blast stoves, not four. This brings greater difficulties to the operation. According to the current configuration of waste air recovery technology, it is impossible to carry out waste air recovery operations, and this operation has a negative impact on the stability of the blast furnace condition.

[0007] Chinese patent document CN103966379A (CN201410223238.0) discloses a waste air recovery device for a hot blast stove with a waste air buffer tank, which can reduce the fluctuations in blast furnace conditions caused by the pressure equalization operation of the hot blast stove; due to its buffering effect, it also reduces the requirements for the air charging capacity of the blast furnace blower. However, in the above patent document, although the waste air of the hot blast stove is used in the initial stage of pressure equalization, the pressure equalization of the hot blast stove still needs to be carried out by the blast furnace blower in the later stage of pressure equalization, which cannot completely solve the problem of pressure fluctuation of the blast furnace blower.

[0008] Chinese patent document CN105803146A (CN201610145660.8) discloses a hot blast stove pressurization method and process apparatus that does not require the participation of blast furnace blasting. This method utilizes an independent and stable high-pressure gas source to pressurize the hot blast stove, eliminating the need for blast furnace blasting in the pressurization (or equalization) process. This eliminates a series of drawbacks associated with blast furnace blasting, thereby improving the stability of the blast furnace condition, increasing blast furnace capacity, saving energy, and reducing blast furnace coke consumption. However, in the aforementioned patent document, the equalization gas cannot be recovered during independent pressurization; and only half of the equalization gas can be recovered during pre-pressurization + independent pressurization. Furthermore, this method is only applicable to four or more hot blast stoves and cannot be implemented for three or fewer hot blast stoves. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide a pressure equalization system and method for the complete recovery of hot blast stove exhaust gas. This invention utilizes a circulating power module to fill the storage tank with gas from the hot blast stove and to fill the hot blast stove with gas from the storage tank. This not only enables the recovery of all exhaust gas and pressure from the hot blast stove and improves heat utilization, but also reduces the temperature drop of the hot blast stove and improves heat utilization by filling the hot blast stove with the recovered exhaust gas for pressure equalization without using the blast furnace blower. Furthermore, it maintains the stability of blast furnace blasting and avoids hazards such as "burden spikes" and "suspended materials" caused by pressurizing the hot blast stove, thus ensuring the stability of blast furnace production and reducing blast furnace energy consumption.

[0010] The technical problem to be solved by the present invention is achieved by the following technical solution: a pressure equalization system for full recovery of waste gas from a hot blast stove, comprising a hot blast stove, a storage tank, a waste gas pressure equalization main pipe, a waste gas pressure equalization main valve, waste gas pressure equalization branch pipes, waste gas pressure equalization branch valves, a waste gas exchange pipeline, a hot blast stove pressure sensor, a storage pressure sensor, and a circulation power module;

[0011] Each hot blast stove is equipped with a waste air equalization branch pipe and a hot blast stove pressure sensor. The hot blast stove pressure sensor is used to monitor the pressure inside the hot blast stove. The waste air equalization branch pipe is equipped with a waste air equalization branch valve. One end of the waste air equalization branch pipe is connected to the hot blast stove, and the other end of the waste air equalization branch pipe is connected to the waste air equalization main pipe.

[0012] The exhaust air equalization main pipe is connected to the storage tank through the exhaust gas exchange pipeline. An exhaust air equalization main valve is installed on the exhaust gas exchange pipeline. A storage pressure sensor is installed on the storage tank to monitor the pressure inside the storage tank.

[0013] The circulating power module is used to introduce gas from the hot blast furnace into the storage tank and to introduce gas from the storage tank into the hot blast furnace.

[0014] Another technical solution of the present invention is that the circulating power module includes a first gas exchange pipeline, a first booster fan, a first shut-off valve, a second gas exchange pipeline, a second booster fan, and a second shut-off valve;

[0015] The first gas exchange pipeline is connected to the waste gas exchange pipeline at both ends, and the connection points are located on both sides of the waste air equalization valve. The first gas exchange pipeline is equipped with a first booster fan and a first shut-off valve.

[0016] The second gas exchange pipeline is connected to the waste gas exchange pipeline at both ends, and the connection points are located on both sides of the waste air equalization valve. The second gas exchange pipeline is equipped with a second booster fan and a second shut-off valve.

[0017] Another aspect of the technical solution of the present invention is that the circulating power module further includes a first gas supply pipe, a third shut-off valve, a second gas supply pipe, and a fourth shut-off valve;

[0018] The first gas supply pipe is connected to the air inlet of the first booster fan, and a third shut-off valve is provided on the first gas supply pipe.

[0019] The second gas supply pipe is connected to the air inlet of the second booster fan, and a fourth shut-off valve is installed on the second gas supply pipe.

[0020] Another technical solution of the present invention is that the circulating power module includes a cylinder drive module and a piston disposed in the storage tank, the piston being capable of reciprocating along the axis of the storage tank;

[0021] The cylinder drive module is used to drive the piston to slide back and forth along the axis of the storage tank.

[0022] Another aspect of the technical solution of the present invention is that the circulating power module further includes a third gas replenishment pipe and a fifth shut-off valve;

[0023] The third gas supply pipe is connected to the inner cavity of the storage tank, and a fifth shut-off valve is provided on the third gas supply pipe.

[0024] The technical solution of the present invention also includes a blast furnace blower, a main cold air pipe, a branch cold air pipe, a cold air equalizing pipe, a cold air valve, a cold air equalizing valve, a main cold air valve, and a cold air regulating valve.

[0025] Each hot air furnace is equipped with a cold air branch pipe and a cold air equalizing pipe. Each cold air branch pipe is equipped with a cold air valve and a cold air regulating valve. Each cold air equalizing pipe is equipped with a cold air equalizing valve. The two ends of the cold air equalizing pipe are connected to the cold air branch pipe respectively, and the two ends of the cold air equalizing pipe are located on both sides of the cold air valve respectively.

[0026] The inlet end of the cold air branch pipe is connected to the cold air main pipe, and the outlet end of the cold air branch pipe is connected to the hot blast stove. The inlet end of the cold air main pipe is equipped with a cold air main valve and a blast furnace blower.

[0027] The present invention also discloses a method for equalizing the pressure of a hot blast stove using the above-mentioned pressure equalization system, including a hot blast stove exhaust gas recovery and pressure equalization method, wherein the hot blast stove is changed alternately, and the hot blast stove exhaust gas recovery and pressure equalization method includes a staged recovery mode and a staged pressure equalization mode.

[0028] The phased recovery mode includes a waste gas non-powered recovery stage and a circulating power module recovery stage. The waste gas non-powered recovery stage is specifically as follows: when one of the hot blast stoves is in the transition period from "air supply" mode to "furnace burning" mode, its corresponding waste air equalization branch valve is opened, and the waste air equalization main valve is opened at the same time. The pressure and gas in the hot blast stove are recovered by using the pressure difference between the hot blast stove and the storage tank. The pressure in the hot blast stove and the storage tank are monitored by the hot blast stove pressure sensor and the storage pressure sensor, respectively. When the pressure difference between the hot blast stove and the storage tank is less than the preset value P1, the waste air equalization main valve is closed.

[0029] Recycling power module recovery stage: After pressurizing the gas in the hot air furnace using the recycling power module, the storage tank is pressurized at a constant flow rate Q1 until the pressure in the storage tank reaches the initial pressure P2, thus completing the recovery of waste gas and waste pressure;

[0030] The phased pressure equalization mode includes a waste gas non-powered pressure equalization stage and a waste gas recirculation power module pressure equalization stage. Specifically, the waste gas non-powered pressure equalization stage is as follows: when one of the hot air furnaces is in the transition period from "furnace burning" mode to "air supply" mode, its corresponding waste air pressure equalization branch valve is opened, and the waste air pressure equalization main valve is opened at the same time. The pressure difference between the storage tank and the hot air furnace is used to equalize the pressure of the hot air furnace. The pressure sensor of the hot air furnace and the storage pressure sensor are used to monitor the pressure in the hot air furnace and the storage tank, respectively. When the pressure difference between the storage tank and the hot air furnace is less than the preset value P3, the waste air pressure equalization main valve is closed.

[0031] Pressure equalization stage of the exhaust gas recirculation power module: After pressurizing the gas in the storage tank using the recirculation power module, the hot air furnace is continued to be pressurized at a constant flow rate Q2 until the pressure in the hot air furnace reaches the equalization pressure P4, thus completing the pressure equalization of the hot air furnace.

[0032] The beneficial effects of this invention are:

[0033] (1) The present invention uses a circulating power module to charge the waste gas in the storage tank into the hot blast stove for pressure equalization, which ensures the constant pressure of the blast furnace blast and maintains the stability of the blast furnace blast. It can avoid the hazards of "rising" and "suspended material" in the blast furnace caused by the pressure of the hot blast stove, ensure the stability of blast furnace production, and reduce the energy consumption of blast furnace production.

[0034] In addition, the circulating power module does not affect other hot blast stoves or blast furnace blast when it recovers waste gas and waste pressure and equalizes pressure. It helps to improve the stability of blast furnace blast and is not limited by the number of hot blast stoves. It is suitable for more than 3 hot blast stoves and has a wide range of applications.

[0035] By pressurizing the gas inside the hot blast furnace and filling it into the storage tank through the circulating power module, it is possible to recover all the waste pressure and waste gas inside the hot blast furnace, and to recover the heat in the waste gas, thus saving energy.

[0036] (2) When the gas in the storage tank of the present invention is used to equalize the pressure of the hot blast stove, the temperature difference between the gas in the storage tank and the gas in the hot blast stove is small, which reduces the temperature drop in the hot blast stove during equalization, so that more heat in the hot blast stove can be used for blast furnace smelting and improve the energy utilization rate.

[0037] (3) The gas in the storage tank is pressurized and fed into the hot air furnace by the circulating power module. It is only necessary to ensure that the gas pressure and gas volume in the storage tank meet the needs of one hot air furnace, thereby reducing the initial pressure in the storage tank and thus reducing the power requirement of the circulating power module. This is beneficial to reduce the volume of the circulating power module, making it easier to arrange, and also helps to reduce the cost of the equipment.

[0038] 4) This invention does not alter the existing hot blast stove exhaust gas pressurization system; it only requires the installation of a main exhaust gas pipe, branch exhaust gas pipes, and a circulating power module. The solution described in this invention is suitable for both new construction and renovation, meeting industrial application requirements. Furthermore, when the circulating power module malfunctions or requires maintenance, the pressure equalization system of the blast furnace blower can be switched to equalize the pressure in the hot blast stove, ensuring a continuous and stable supply of hot air to the blast furnace and increasing the stability of the hot blast stove's equalization system. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the pressure equalization system for the complete recovery of hot blast furnace exhaust gas as described in Embodiment 1 of the present invention;

[0040] Figure 2 This is a schematic diagram of the pressure equalization system for the complete recovery of hot blast stove exhaust gas as described in Embodiment 2 of the present invention;

[0041] Figure 3This is a schematic diagram of the pressure equalization system for the complete recovery of hot blast furnace exhaust gas as described in Embodiment 3 of the present invention;

[0042] Figure 4 This is a schematic diagram illustrating the working principle of the waste gas non-powered recovery stage in the hot blast stove pressure equalization method described in Embodiment 1 of the present invention.

[0043] Figure 5 This is a schematic diagram illustrating the working principle of the circulating power module recovery stage in the hot blast stove pressure equalization method described in Embodiment 1 of the present invention.

[0044] Figure 6 This is a schematic diagram illustrating the working principle of the non-powered pressure equalization stage of the hot blast stove pressure equalization method described in Embodiment 1 of the present invention.

[0045] Figure 7 This is a schematic diagram illustrating the working principle of the pressure equalization stage of the waste gas circulation power module in the hot blast stove pressure equalization method described in Embodiment 1 of the present invention;

[0046] In the diagram, 101 is the hot air furnace pressure sensor and 102 is the storage pressure sensor;

[0047] 1. Hot air furnace, 2. Storage tank, 3. Waste air pressure equalization main pipe, 4. Waste air pressure equalization main valve, 5. Waste air pressure equalization branch pipe, 6. Waste air pressure equalization branch valve, 7. Waste gas exchange pipeline;

[0048] 8 First gas exchange pipeline, 9 First booster fan, 10 First shut-off valve, 11 Second gas exchange pipeline, 12 Second booster fan, 13 Second shut-off valve, 14 First gas supply pipeline, 15 Third shut-off valve, 16 Second gas supply pipeline, 17 Fourth shut-off valve;

[0049] 18 Piston, 19 Third Gas Supply Pipe, 20 Fifth Shut-off Valve;

[0050] 100 Blast Furnace Blower, 21 Cold Air Main Pipe, 22 Cold Air Branch Pipe, 23 Cold Air Equalizing Pipe, 24 Cold Air Valve, 25 Cold Air Equalizing Valve, 26 Cold Air Main Valve, 27 Cold Air Regulating Valve, 28 Hot Air Branch Pipe, 29 Hot Air Valve, 30 Hot Air Main Pipe, 31 Blast Furnace, 32 Mixing Air Valve, 33 Mixing Air Regulating Valve, 34 Flue Branch Pipe, 35 Waste Gas Branch Pipe, 36 Flue Gas Valve, 37 Waste Gas Valve, 38 Flue Main Pipe, 39 Flue Gas Valve, 40 Chimney, 41 Backflow Shutdown Valve, 42 Backflow Shutdown Chimney. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the invention is not limited to the scope of the embodiments described. The following embodiments are applicable to three or more hot blast stoves.

[0052] Example 1

[0053] like Figure 1As shown, a pressure equalization system for full recovery of waste gas from a hot blast stove includes a hot blast stove 1, a storage tank 2, a waste gas pressure equalization main pipe 3, a waste gas pressure equalization main valve 4, a waste gas pressure equalization branch pipe 5, a waste gas pressure equalization branch valve 6, a waste gas exchange pipeline 7, a hot blast stove pressure sensor 101, a storage pressure sensor 102, and a circulating power module.

[0054] Each hot blast stove 1 is equipped with a waste air equalization branch pipe 5 and a hot blast stove pressure sensor 101. The hot blast stove pressure sensor 101 is used to monitor the pressure inside the hot blast stove 1. A waste air equalization branch valve 6 is installed on the waste air equalization branch pipe 5. One end of the waste air equalization branch pipe 5 is connected to the hot blast stove 1. In order to reduce the modification cost, facilitate later maintenance, and reduce the impact on the hot blast stove 1, the end of the waste air equalization branch pipe 5 connected to the hot blast stove 1 is set on the flue branch pipe 34 in the existing structure. The other end of the waste air equalization branch pipe 5 is connected to the waste air equalization main pipe 3.

[0055] The exhaust gas exchange pipeline 7 is located between the exhaust air equalization main pipe 3 and the storage tank 2. The exhaust air equalization main pipe 3 is connected to the storage tank 2 through the exhaust gas exchange pipeline 7. An exhaust air equalization main valve 4 is installed on the exhaust gas exchange pipeline 7. A storage pressure sensor 102 is installed on the storage tank 2. The storage pressure sensor 102 is used to monitor the pressure inside the storage tank 2.

[0056] The circulating power module is used to introduce gas from the hot blast furnace 1 into the storage tank 2 and to introduce gas from the storage tank 2 into the hot blast furnace 1.

[0057] Specifically, such as Figure 1 As shown, the circulating power module includes a first gas exchange pipeline 8, a first booster fan 9, a first shut-off valve 10, a second gas exchange pipeline 11, a second booster fan 12, and a second shut-off valve 13.

[0058] The first gas exchange pipeline 8 is connected to the waste gas exchange pipeline 7 at both ends, and the connection points are located on both sides of the waste air equalization valve 4. The first gas exchange pipeline 8 is equipped with a first booster fan 9 and a first shut-off valve 10.

[0059] The two ends of the second gas exchange pipeline 11 are connected to the waste gas exchange pipeline 7 respectively, and the connection points are located on both sides of the waste air equalization valve 4. The second gas exchange pipeline 11 is equipped with a second booster fan 12 and a second shut-off valve 13.

[0060] To prevent gas leakage in the pipeline from causing the gas volume in the storage tank 2 to be insufficient to meet the pressure equalization requirements of the hot air furnace 1, the circulating power module is also equipped with a first gas supply pipe 14, a third shut-off valve 15, a second gas supply pipe 16, and a fourth shut-off valve 17.

[0061] The first gas replenishment pipe 14 is connected to the air inlet of the first booster fan 9, and a third shut-off valve 15 is installed on the first gas replenishment pipe 14. When there is a gas leak in the exhaust gas of the hot blast furnace 1, the third shut-off valve 15 is opened, and under the action of the first booster fan 9, gas is replenished into the storage tank 2 through the first gas replenishment pipe 14.

[0062] The second gas supply pipe 16 is connected to the air inlet of the second booster fan 12, and a fourth shut-off valve 17 is installed on the second gas supply pipe 16. When gas leakage occurs during pressure equalization of the hot blast furnace 1, the fourth shut-off valve 17 is opened, and gas is supplied into the hot blast furnace 1 through the second gas supply pipe 16 under the action of the second booster fan 12.

[0063] like Figure 1 As shown, the air supply mechanism of the hot blast stove includes a blast furnace blower 100, a cold air main pipe 21, a cold air branch pipe 22, a cold air valve 24, a cold air main valve 26, and a cold air regulating valve 27.

[0064] Each hot air furnace 1 is equipped with a cold air branch pipe 22, and each cold air branch pipe 22 is equipped with a cold air valve 24 and a cold air regulating valve 27.

[0065] The inlet end of the cold air branch pipe 22 is connected to the cold air main pipe 21, and the outlet end of the cold air branch pipe 22 is connected to the hot blast stove 1. The inlet end of the cold air main pipe 21 is equipped with a cold air main valve 26 and a blast furnace blower 100. In this invention, the circulating power module equalizes the pressure of the hot blast stove 1 through the second booster blower 12, without affecting the blowing pressure of the blast furnace blower 100.

[0066] like Figure 1 As shown, each hot blast stove 1 is equipped with a hot blast branch pipe 28, and each hot blast branch pipe 28 is equipped with a hot blast valve 29. The hot blast stove 1 is connected to the hot blast main pipe 30 through the hot blast branch pipe 28. One end of the hot blast main pipe 30 is connected to the blast furnace 31, and the other end of the hot blast main pipe 30 is connected to the backflow shut-off chimney 42 through the backflow shut-off valve 41. The outlet end of the cold blast main pipe 21 is connected to the hot blast main pipe 30, and the outlet end of the cold blast main pipe 21 is equipped with a mixing valve 32 and a mixing regulating valve 33. When the circulating power module is used to equalize the pressure in the hot blast stove 1 so that the pressure inside the hot blast stove 1 is equal to the blast pressure of the blast furnace blower 100, the cold blast valve 24, the cold blast regulating valve 27, and the hot blast valve 29 can be opened, thereby realizing the stable delivery of hot blast from the hot blast stove 1 to the blast furnace 31.

[0067] Each hot blast stove 1 is equipped with two flue branch pipes 34 and one exhaust gas branch pipe 35. Each flue branch pipe 34 is equipped with a flue gas valve 36, and each exhaust gas branch pipe 35 is equipped with an exhaust gas valve 37. The inlet end of the flue branch pipe 34 is connected to the hot blast stove 1, and the outlet end of the flue branch pipe 34 is connected to the main flue pipe 38. The exhaust gas branch pipe 35 is installed on one of the flue branch pipes 34, and the two ends of the exhaust gas branch pipe 35 are respectively installed at the two ends of the flue gas valve 36. The outlet end of the main flue pipe 38 is connected to the chimney 40 through the flue valve 39.

[0068] A method for equalizing the pressure of a hot blast stove using the pressure equalization system described in this embodiment includes a hot blast stove exhaust gas recovery and pressure equalization method. The hot blast stove exhaust gas recovery and pressure equalization method includes a staged recovery mode and a staged pressure equalization mode. To ensure a stable supply of hot blast to the blast furnace, the hot blast stove 1 is switched on an alternating basis. Therefore, when recovering exhaust gas from the hot blast stove 1, the initial pressure of the storage tank 2 is 0. When equalizing the pressure of the hot blast stove 1 using the circulating power module, the initial pressure in the storage tank 2 should be at least equal to the pressure value of the hot blast stove 1 in the air supply state. The valves corresponding to the hot blast stove 1 that are not mentioned are all in the closed state and will not be described in detail here.

[0069] The phased recycling mode includes a waste gas non-powered recycling phase and a recirculating power module recycling phase, wherein the waste gas non-powered recycling phase specifically includes: Figure 4 As shown, when one of the hot blast stoves 1 is transitioning from "air supply" mode to "furnace burning" mode, its corresponding waste air equalization branch valve 6 is opened, and the waste air equalization main valve 4 is opened simultaneously. The pressure and gas inside the hot blast stove 1 are recovered using the pressure difference between the hot blast stove 1 and the storage tank 2. The pressure inside the hot blast stove 1 and the storage tank 2 are monitored by the hot blast stove pressure sensor 101 and the storage pressure sensor 102, respectively. When the pressure difference between the hot blast stove 1 and the storage tank 2 is less than a preset value P1, the waste air equalization main valve 4 is closed. When using the pressure difference between the hot blast stove 1 and the storage tank 2 to recover waste gas, the recovery speed will slow down as the pressure difference decreases in the later stages. To improve the recovery speed of waste gas and waste pressure, when the pressure difference between the hot blast stove 1 and the storage tank 2 is less than the preset value P1, the system can be switched to a circulating power module for recovery, thereby improving the recovery efficiency of waste gas and waste pressure.

[0070] like Figure 5 As shown, in the recycling phase of the circulating power module: the gas in the hot air furnace 1 is pressurized by the circulating power module and then the storage tank 2 is pressurized at a constant flow rate Q1. Specifically, the first shut-off valve 10 is opened and the first booster fan 9 is started to draw the gas in the hot air furnace 1 into the storage tank 2 until the pressure in the storage tank 2 reaches the initial pressure P2, thus completing the recycling of waste gas and waste pressure. The first booster fan 9, the first shut-off valve 10 and the waste air equalization branch valve 6 are then closed. The gas flow rate is adjusted by controlling the speed of the first booster fan 9.

[0071] When using the first booster fan 9 to recover waste gas, the volume of the storage tank 2 is fixed. In the event of a leak in the pipeline, in order to ensure that the pressure P2 inside the storage tank 2 is equal to the pressure value of the hot blast stove 1 in the air supply state, i.e., the air supply pressure of the blast furnace blower 100, the third shut-off valve 15 is opened when recovering waste gas, and gas is supplied to the storage tank 2 through the first gas supply pipe 14 to compensate for the amount of gas leaked in the pipeline.

[0072] The phased pressure equalization mode includes a non-powered pressure equalization stage for exhaust gas and a pressure equalization stage for exhaust gas recirculation power modules. Specifically, the non-powered pressure equalization stage for exhaust gas is as follows: Figure 6 As shown, when one of the hot blast stoves 1 is transitioning from "burning" mode to "blowing" mode, its corresponding waste air equalization branch valve 6 is opened, and the waste air equalization main valve 4 is opened simultaneously. The pressure difference between the storage tank 2 and the hot blast stove 1 is used to equalize the pressure in the hot blast stove 1. The pressure sensor 101 and the storage pressure sensor 102 monitor the pressure in the hot blast stove 1 and storage tank 2, respectively. When the pressure difference between the storage tank 2 and the hot blast stove 1 is less than the preset value P3, the waste air equalization main valve 4 is closed. When equalizing pressure using the pressure difference between the hot blast stove 1 and the storage tank 2, the equalization speed will slow down as the pressure difference decreases in the later stages. To improve the equalization speed of the hot blast stove, when the pressure difference between the hot blast stove 1 and the storage tank 2 is less than the preset value P3, the system can switch to a circulating power module for equalization, thereby increasing the equalization speed.

[0073] like Figure 7 As shown, in the pressure equalization stage of the exhaust gas recirculation power module: the gas in the storage tank 2 is pressurized by the recirculation power module and then the hot air furnace 1 is pressurized at a constant flow rate Q2. Specifically, the second shut-off valve 13 is opened and the second booster fan 12 is started to draw the gas in the storage tank 2 into the hot air furnace 1 until the pressure in the hot air furnace 1 reaches the equalization pressure P4, thus completing the pressure equalization of the hot air furnace 1. The second booster fan 12, the second shut-off valve 13 and the exhaust gas equalization branch valve 6 are then closed. The gas flow rate is adjusted by controlling the speed of the second booster fan 12.

[0074] When the second booster fan 12 is used for pressure equalization, the volume of the storage tank 2 is fixed, and the pressure P2 inside the storage tank 2 is equal to the pressure value of the hot air furnace 1 in the air supply state. When a special situation occurs in the pipeline, and the amount of gas leakage causes the amount of gas in the storage tank 2 to be insufficient to meet the pressure equalization requirements of the hot air furnace 1, the fourth shut-off valve 17 needs to be opened during the pressure equalization process, and gas is added to the hot air furnace 1 through the second gas replenishment pipe 16 to compensate for the amount of gas leakage in the pipeline.

[0075] Example 2

[0076] like Figure 2As shown, the difference from Embodiment 1 is that the circulating power module includes a cylinder drive module and a piston 18 disposed in the storage tank 2, the piston 18 being able to slide back and forth along the axis of the storage tank 2.

[0077] The cylinder drive module is used to drive the piston 18 to slide back and forth along the axis of the storage tank 2.

[0078] To prevent gas leakage in the pipeline from causing the gas volume in the storage tank 2 to be insufficient to meet the pressure equalization of the hot air furnace 1, the circulating power module is also equipped with a third gas replenishment pipe 19 and a fifth shut-off valve 20.

[0079] The third gas supply pipe 19 communicates with the inner cavity of the storage tank 2, and a fifth shut-off valve 20 is installed on the third gas supply pipe 19. Since the volume of the storage tank 2 is adjustable, when a gas leak occurs in the pipeline, the fifth shut-off valve 20 can be opened simultaneously when recovering the waste gas in the hot air furnace 1, and gas can be supplied to the storage tank 2 under the action of the cylinder drive module. The gas capacity of the storage tank 2 can be adjusted according to the amount of gas leakage.

[0080] like Figure 2 As shown, when the pressure equalization system described in this embodiment is used to equalize the pressure of the hot blast stove, when one of the hot blast stoves 1 is in the transition period from "air supply" mode to "furnace burning" mode, the recycling phase of the circulating power module is specifically as follows: the piston 18 is driven by the cylinder drive module to move axially along the storage tank 2, and the gas in the hot blast stove 1 is pressurized and then drawn into the storage tank 2 at a constant flow rate Q1.

[0081] When using a cylinder-driven module for waste gas recovery, the volume of storage tank 2 is variable. In the event of a pipeline leak, the initial pressure P2 of storage tank 2 is set to be greater than the pressure value of a hot air furnace 1 in the air supply state to compensate for the amount of gas leakage during the later pressure equalization. During waste gas recovery, the fifth shut-off valve 20 is opened, and gas is supplied to storage tank 2 through the third gas supply pipe 19.

[0082] When one of the hot blast stoves 1 is in the transition from "burning" mode to "blowing" mode, the pressure equalization stage of the exhaust gas circulation power module is specifically as follows: the piston 18 is driven by the cylinder drive module to move axially along the storage tank 2, pushing the gas in the storage tank 2 into the hot blast stove 1.

[0083] When the cylinder-driven module is used for pressure equalization, the volume of the storage tank 2 is variable. In the event of a pipeline leak, the initial pressure P2 of the storage tank 2 is set to be greater than the pressure value of the hot air furnace 1 in the air supply state, thereby compensating for gas leakage during the later pressure equalization. Therefore, it is not necessary to add gas to the hot air furnace 1 during pressure equalization.

[0084] Example 3

[0085] like Figure 3 As shown, the difference from Embodiment 1 is that the pressure equalization system for the complete recovery of hot blast stove exhaust gas also includes the pressure equalization module of the blast furnace blower in the prior art. The pressure equalization module of the blast furnace blower includes a blast furnace blower 100, a cold air main pipe 21, a cold air branch pipe 22, a cold air pressure equalization pipe 23, a cold air valve 24, a cold air pressure equalization valve 25, a cold air main valve 26, and a cold air regulating valve 27.

[0086] Each hot air furnace 1 is equipped with a cold air branch pipe 22 and a cold air equalizing pipe 23. Each cold air branch pipe 22 is equipped with a cold air valve 24 and a cold air regulating valve 27. Each cold air equalizing pipe 23 is equipped with a cold air equalizing valve 25. The two ends of the cold air equalizing pipe 23 are connected to the cold air branch pipe 22 respectively, and the two ends of the cold air equalizing pipe 23 are located on both sides of the cold air valve 24 respectively.

[0087] The inlet end of the cold air branch pipe 22 is connected to the cold air main pipe 21, and the outlet end of the cold air branch pipe 22 is connected to the hot blast stove 1. The inlet end of the cold air main pipe 21 is equipped with a cold air main valve 26 and a blast furnace blower 100. When the circulating power module fails, the pressure equalization of the hot blast stove 1 can still be achieved through the blast furnace blower 100.

[0088] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A pressure equalization system for the complete recovery of exhaust gas from a hot blast stove, characterized in that: It includes a hot air furnace (1), a storage tank (2), a waste air pressure equalization main pipe (3), a waste air pressure equalization main valve (4), a waste air pressure equalization branch pipe (5), a waste air pressure equalization branch valve (6), a waste gas exchange pipeline (7), a hot air furnace pressure sensor (101), a storage pressure sensor (102), and a circulating power module; Each hot blast stove (1) is equipped with a waste air equalization branch pipe (5) and a hot blast stove pressure sensor (101). The hot blast stove pressure sensor (101) is used to monitor the pressure inside the hot blast stove (1). A waste air equalization branch valve (6) is installed on the waste air equalization branch pipe (5). One end of the waste air equalization branch pipe (5) is connected to the hot blast stove (1), and the other end of the waste air equalization branch pipe (5) is connected to the waste air equalization main pipe (3). The exhaust gas equalization main pipe (3) is connected to the storage tank (2) through the exhaust gas exchange pipe (7). The exhaust gas exchange pipe (7) is equipped with an exhaust gas equalization main valve (4). The storage tank (2) is equipped with a storage pressure sensor (102). The storage pressure sensor (102) is used to monitor the pressure inside the storage tank (2). It also includes a blast furnace blower (100), a cold air main pipe (21), and cold air branch pipes (22). The inlet end of the cold air branch pipe (22) is connected to the cold air main pipe (21), and the outlet end of the cold air branch pipe (22) is connected to the hot blast stove (1). The inlet end of the cold air main pipe (21) is equipped with a cold air main valve (26) and a blast furnace blower (100). The circulating power module is used to introduce gas from the hot blast stove (1) into the storage tank (2) and to introduce gas from the storage tank (2) into the hot blast stove (1) to ensure the constant pressure of the blast furnace blast. The circulating power module includes a cylinder drive module and a piston (18) disposed in the storage tank (2), the piston (18) being able to slide back and forth along the axis of the storage tank (2); The cylinder drive module is used to drive the piston (18) to slide back and forth along the axis of the storage tank (2); The circulating power module also includes a third gas supply pipe (19) and a fifth shut-off valve (20); The third gas supply pipe (19) is connected to the inner cavity of the storage tank (2), and a fifth shut-off valve (20) is provided on the third gas supply pipe (19).

2. The pressure equalization system for complete recovery of hot blast stove exhaust gas according to claim 1, characterized in that: It also includes a cold air equalization pipe (23), a cold air valve (24), a cold air equalization valve (25), and a cold air regulating valve (27); Each hot air furnace (1) is provided with a cold air branch pipe (22) and a cold air equalizing pipe (23). Each cold air branch pipe (22) is provided with a cold air valve (24) and a cold air regulating valve (27). Each cold air equalizing pipe (23) is provided with a cold air equalizing valve (25). The two ends of the cold air equalizing pipe (23) are respectively connected to the cold air branch pipe (22), and the two ends of the cold air equalizing pipe (23) are respectively located on both sides of the cold air valve (24).

3. A method for equalizing the pressure of a hot blast stove using the pressure equalization system described in claim 1 or 2, characterized in that: The method includes a hot blast stove exhaust gas recovery and pressure equalization method, wherein the hot blast stove (1) is replaced alternately, and the hot blast stove exhaust gas recovery and pressure equalization method includes a phased recovery mode and a phased pressure equalization mode. The phased recovery mode includes a waste gas non-powered recovery stage and a circulating power module recovery stage. The waste gas non-powered recovery stage is as follows: when one of the hot air furnaces (1) is in the transition period from "air supply" mode to "furnace burning" mode, its corresponding waste air equalization branch valve (6) is opened, and the waste air equalization main valve (4) is opened at the same time. The pressure and gas in the hot air furnace (1) are recovered by using the pressure difference between the hot air furnace (1) and the storage tank (2). The pressure in the hot air furnace (1) and the storage tank (2) are monitored by the hot air furnace pressure sensor (101) and the storage pressure sensor (102) respectively. When the pressure difference between the hot air furnace (1) and the storage tank (2) is less than the preset value P1, the waste air equalization main valve (4) is closed. Recycling power module recovery stage: After pressurizing the gas in the hot air furnace (1) using the recycling power module, the storage tank (2) is pressurized at a constant flow rate Q1 until the pressure in the storage tank (2) reaches the initial pressure P2, thus completing the recovery of waste gas and waste pressure; The phased pressure equalization mode includes a waste gas non-powered pressure equalization stage and a waste gas recirculation power module pressure equalization stage. Specifically, the waste gas non-powered pressure equalization stage is as follows: when one of the hot air furnaces (1) is in the transition period from the "burning" mode to the "blowing" mode, its corresponding waste air pressure equalization branch valve (6) is opened, and the waste air pressure equalization main valve (4) is opened at the same time. The pressure difference between the storage tank (2) and the hot air furnace (1) is used to equalize the pressure of the hot air furnace (1). The pressure sensor (101) of the hot air furnace and the storage pressure sensor (102) are used to monitor the pressure in the hot air furnace (1) and the storage tank (2) respectively. When the pressure difference between the storage tank (2) and the hot air furnace (1) is less than the preset value P3, the waste air pressure equalization main valve (4) is closed. Pressure equalization stage of exhaust gas recirculation power module: After pressurizing the gas in storage tank (2) using the recirculation power module, the hot air furnace (1) is pressurized at a constant flow rate Q2 until the pressure in the hot air furnace (1) reaches the equalization pressure P4, thus completing the pressure equalization of the hot air furnace (1).

Images