Blast furnace waste heat air recovery and stable pressure air supply device

Abstract

The present application belongs to the technical field of blast furnace, and relates to a blast furnace waste heat wind recovery and stable pressure air supply device, which comprises at least three hot blast furnaces; each hot blast furnace is provided with a hot blast branch pipe and a cold blast branch pipe, a plurality of hot blast branch pipes are communicated with a hot blast main pipe, and the hot blast main pipe is communicated with a blast furnace; a plurality of cold blast branch pipes are communicated with a cold blast main pipe, and the cold blast main pipe is communicated with a blower; the blast furnace waste heat wind recovery and stable pressure air supply device further comprises an ejector, an air compressor and a high-pressure gas storage tank; the high-pressure gas storage tank is provided with a pressure charging pipe communicated with an inlet and an equalizing main pipe communicated with an outlet; the ejector is provided with an inlet injection pipe, an outlet injection pipe and a gas injection pipe; and a controller is in communication connection with each valve and the air compressor, so that the hot blast furnace can be alternately switched from the air supply mode to the combustion mode or from the combustion mode to the air supply mode. Thus, the problems that all the remaining waste heat wind of the hot blast furnace cannot be recovered and the blast furnace blast wind pressure is unstable in the prior art are solved.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace technology and relates to a blast furnace waste heat blast recovery and pressure stabilization air supply device. Background Technology

[0002] Blast furnace metallurgy has advantages such as good technical and economic indicators, simple process, large production volume, high labor productivity and low energy consumption, and is the main method of modern metallurgy.

[0003] Blast furnace metallurgy typically uses three or four hot blast stoves. One hot blast stove is used for blast supply, while the others are used for combustion and heat storage, alternating between the two. When a hot blast stove is configured as a blast stove, it can supply high-temperature gas to the blast furnace, increasing the internal temperature and combustion efficiency. When the blast stove is switched to a combustion stove, some of the high-temperature gas supplied to the blast furnace cannot be completely delivered, resulting in residual hot blast. For safety reasons, each time the blast stove is switched to a combustion stove, the residual hot blast in the stopped hot blast stove needs to be vented through the flue or chimney, resulting in energy waste. Each time the blast stove is switched from combustion mode to blast mode, the low pressure inside the hot blast stove causes pressure fluctuations during blast supply, posing risks such as blast furnace charge issues. Some companies increase the blast furnace blower's airflow before the hot blast stove is switched to blast, partially filling the hot blast stove to pressurize it. Once the required air pressure is reached, the blower's airflow is reduced, and then the blast mode is started. The first scenario results in a waste of residual heat air; the second scenario requires frequent adjustments to the fan's airflow.

[0004] In view of this, it is necessary to improve the existing waste heat recovery and air pressure stabilization of blast furnaces in order to achieve full recovery of waste heat air and stable air pressure, save energy consumption, and ensure the stable and smooth operation of the blast furnace. Summary of the Invention

[0005] The purpose of this invention is to provide a blast furnace waste heat blast recovery and pressure stabilization air supply device to solve the problems of not being able to recover all the residual hot air from the hot blast stove and the unstable blast furnace blast pressure in the prior art.

[0006] To achieve the above objectives, the present invention provides a blast furnace waste heat blast recovery and pressure stabilization air supply device, comprising at least three hot blast stoves, which are connected by a controller for communication. The controller is used to alternately configure one of the hot blast stoves as the air supply stove and the other hot blast stoves as combustion stoves.

[0007] Each hot blast stove is equipped with hot blast branch pipes and cold blast branch pipes. Multiple hot blast branch pipes are connected to the hot blast main pipe, which is connected to the blast furnace. Each hot blast branch pipe is equipped with a hot blast valve. Multiple cold blast branch pipes are connected to the cold blast main pipe, which is connected to the blower. Each cold blast branch pipe is equipped with a cold blast valve.

[0008] The blast furnace waste heat blast recovery and pressure stabilization air supply device also includes an ejector, an air compressor, and a high-pressure air storage tank.

[0009] The high-pressure gas storage tank has an inlet and an outlet. The inlet is connected to a pressurization pipe, which is equipped with a pressurization valve. The outlet is connected to a pressure equalization main pipe, which is equipped with a pressure equalization main valve.

[0010] The ejector is provided with an inlet ejector tube, an outlet ejector tube, and a gas ejector tube, wherein the inlet ejector tube is connected to the equalizing main pipe; the equalizing main pipe is provided with at least three equalizing branch pipes, each of the equalizing branch pipes being connected to the cold air branch pipe in a one-to-one correspondence; each of the equalizing branch pipes is provided with an equalizing branch valve; and the inlet ejector tube is also provided with an inlet ejector valve.

[0011] The gas ejector tube is connected to the air compressor, and a gas ejector valve is provided on the gas ejector tube; wherein, the air compressor is provided with an air pipe connected to the atmosphere, and a filter is provided on the air pipe.

[0012] The outlet ejector tube is connected to the pressurization tube, and the outlet ejector tube is equipped with an outlet ejector valve.

[0013] The controller is communicatively connected to the hot air valve, cold air valve, pressurization valve, equalizing main valve, equalizing branch valve, inlet ejector valve, gas ejector valve, outlet ejector valve, and air compressor. The controller controls the opening and closing of each valve and the start and stop of the air compressor accordingly, so as to alternately switch one of the hot air furnaces from the air supply mode to the combustion mode. In the combustion mode, the hot air furnace is a combustion furnace; in the air supply mode, the hot air furnace is an air supply furnace.

[0014] Alternatively, in the blast furnace waste heat blast recovery and pressure stabilization air supply device, the control method for switching the hot blast stove from the air supply mode to the combustion mode is as follows:

[0015] The hot air valve and the cold air valve are closed to stop air supply; the equalizing branch valve is opened, the air compressor is started, and the gas ejector valve, the outlet ejector valve, and the inlet ejector valve are opened in sequence so that the waste hot air in the hot blast furnace is drawn into the high-pressure gas storage tank by the ejector.

[0016] When the hot blast stove needs to stop supplying air and switch to combustion mode, the hot air valve and cold air valve begin to close until they are completely closed and the air supply stops. At this time, the waste hot air in the hot blast stove needs to be extracted to pressurize the high-pressure storage tank. At this time, the equalizing branch valve opens, the air compressor starts, and the gas ejector valve, outlet ejector valve, and inlet ejector valve open in sequence. The waste hot air in the hot blast stove is extracted into the high-pressure gas storage tank by the ejector.

[0017] When the pressure inside the hot blast stove is reduced to 0 kPa, the high-temperature, high-pressure waste heat air inside the stove is completely recovered. After closing the equalizing branch valve, the outlet ejector valve, gas ejector valve, and inlet ejector valve are then closed, and the air compressor is shut down. The gas valve, combustion air valve, and exhaust gas valve on the hot blast stove are then opened, allowing the hot blast stove to switch from the air supply mode to the combustion mode.

[0018] In this way, by using an air compressor and ejector, all the waste heat air from the stopped hot blast stove is recovered into a high-pressure gas storage tank, achieving complete heat recovery of all waste heat air from the hot blast stove, improving recovery efficiency, and reducing the fuel ratio. Furthermore, the use of an ejector ensures both the recovery of high-temperature gas and a working pressure higher than the blower pressure, thus guaranteeing safe and efficient operation throughout the entire process.

[0019] Furthermore, the extraction time of waste hot air in the hot blast stove is less than or equal to the time when the hot blast stove switches from the air supply mode to the combustion mode. This allows for the complete recovery of waste hot air without affecting the operation mode of the existing hot blast stove. It is convenient to use and easy to assemble and modify with other structures.

[0020] Alternatively, the extraction time of the waste hot air in the hot blast stove is less than or equal to the time it takes for the hot blast stove to switch from the air supply mode to the combustion mode.

[0021] Alternatively, in the blast furnace waste heat blast recovery and pressure stabilization air supply device, the control method for switching the hot blast stove from combustion mode to air supply mode is as follows:

[0022] When the hot blast stove needs to switch from combustion mode to air supply mode, the gas valve, combustion air valve and exhaust gas valve on the hot blast stove are closed to stop combustion; before air supply, the equalizing branch valve and the equalizing main valve are opened in sequence.

[0023] High-pressure waste heat air from the high-pressure gas storage tank is pressurized into the hot blast furnace. When the pressure inside the hot blast furnace reaches the air supply pressure value, the pressure equalization branch valve and the pressure equalization main valve are closed. At this time, the pressure inside the hot blast furnace is the same as the pressure of the cold air main pipe and the hot air main pipe. The pressure inside the hot blast furnace reaches the air supply pressure, and the pressurization is completed. The air supply pressure equalization of the hot blast furnace is realized. At this time, the hot blast furnace has the conditions for stable pressure air supply.

[0024] Gradually open the cold air valve and hot air valve on the hot air furnace, and the hot air furnace will switch from combustion mode to air supply mode.

[0025] Optionally, in the blast furnace waste heat blast recovery and pressure stabilization air supply device, the hot blast stove is pressurized in advance before air supply.

[0026] The above technical solution utilizes an ejector to recover waste heat from the hot blast stove, then pressurizes this waste heat and supplies air to the hot blast stove. This utilizes the waste heat from the hot blast stove, recovering heat and reducing the fuel ratio; it also stabilizes the air pressure, ensuring a continuous and stable blast furnace blast pressure, thus achieving stable blast furnace operation. This achieves complete heat recovery from the waste heat of the hot blast stove, improving recovery efficiency. By recovering heat and pressurizing it into the cold air from the hot blast stove, the temperature of the cold air is increased, which in turn increases the temperature of the hot air. This device has a simple structure, low cost, and is easy to modify, solving the problems of existing technologies in recovering all residual hot air from the hot blast stove and maintaining a continuous and stable blast furnace blast pressure. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the blast furnace waste heat blast recovery and pressure stabilization air supply device provided by the present invention.

[0029] In the above attached figures:

[0030] 10-Blower; 20-Combustion furnace; 30-Blast furnace; 40-Blast furnace; 50-Air compressor; 60-Ejector; 70-High-pressure gas storage tank; 11-Cold air valve; 101-Cold air duct; 102-Cold air branch duct; 21-Hot air valve; 203-Hot air duct; 201-Hot air branch duct; 51-Pressure charging valve; 501-Air duct; 502-Pressure charging pipe; 61-Inlet ejector valve; 601-Inlet ejector pipe; 62-Ejector valve; 602-Ejector pipe; 63-Outlet ejector valve; 603-Outlet ejector pipe; 71-Equalizing valve; 701-Equalizing main pipe; 72-Equalizing branch valve; 702-Equalizing branch pipe. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that while these descriptions of embodiments are intended to aid in understanding the present invention, they do not constitute a limitation thereof.

[0032] The specific structural and functional details disclosed herein are for illustrative purposes only and are intended to describe exemplary embodiments of the invention. However, the invention may be embodied in many alternative forms and should not be construed as being limited to the embodiments described herein.

[0033] See Figure 1As shown, the blast furnace waste heat blast recovery and pressure stabilization air supply device includes at least three hot blast stoves. The hot blast stoves are connected by a controller, which is used to alternately configure one of the hot blast stoves as the air supply stove 30 and the other hot blast stoves as the combustion stoves 20. Each hot blast stove is equipped with a hot blast branch pipe 201 and a cold blast branch pipe 102. The multiple hot blast branch pipes 201 are all connected to the hot blast main pipe 203, which is connected to the blast furnace 40. Each hot blast branch pipe 201 is equipped with a hot blast valve 21. The multiple cold blast branch pipes 102 are all connected to the cold blast main pipe 101, which is connected to the blower 10. Each cold blast branch pipe 102 is equipped with a cold blast valve 11.

[0034] The blast furnace waste heat blast recovery and pressure stabilization air supply device also includes an ejector 60, an air compressor 50, and a high-pressure gas storage tank 70. The high-pressure gas storage tank 70 has an inlet and an outlet. The inlet is connected to a pressurization pipe 502, which is equipped with a pressurization valve 51. The outlet is connected to a pressure equalization main pipe 701, which is equipped with a pressure equalization main valve 71. The ejector 60 has an inlet ejector pipe 601, an outlet ejector pipe 603, and a gas ejector pipe 602. The inlet ejector pipe 601 is connected to the pressure equalization main pipe 701. The pressure equalization main pipe 701 has at least three pressure equalization branch pipes 702, each correspondingly connected to a cold air branch pipe 102. Each pressure equalization branch pipe 702 is equipped with a pressure equalization branch valve 72. The inlet ejector pipe 601 is also equipped with an inlet ejector valve 61.

[0035] The gas ejector tube 602 is connected to the air compressor 50, and a gas ejector valve 62 is provided on the gas ejector tube 602; wherein, the air compressor 50 is provided with an air pipe connected to the atmosphere, and a filter is provided on the air pipe; the outlet ejector tube 603 is connected to the pressurization pipe, and an outlet ejector valve 63 is provided on the outlet ejector tube 603.

[0036] The controller is connected to the cold air valve 11, hot air valve 21, pressurization valve 51, inlet ejector valve 61, gas ejector valve 62, outlet ejector valve 63, equalizing main valve 71, equalizing branch valve 72, and air compressor 50 to control the opening and closing of each valve and the start and stop of the air compressor, so as to alternately switch the hot air furnace from the air supply mode to the combustion mode or from the combustion mode to the air supply mode; in the combustion mode, the hot air furnace is a combustion furnace 20; in the air supply mode, the hot air furnace is an air supply furnace 30.

[0037] Through the above technical solution, the waste heat air from the hot blast stove is recovered using the ejector 60, and then the waste heat air is pressurized and supplied to the hot blast stove that needs air supply. On the one hand, the waste heat air from the hot blast stove is utilized to recover heat and reduce the fuel ratio; on the other hand, the air pressure is stabilized, ensuring the continuous and stable blast air pressure of blast furnace 40, and achieving stable operation of blast furnace 40. Thus, all the waste heat air from the hot blast stove is recovered, improving the recovery efficiency. By recovering the heat and pressurizing it into the cold air from the hot blast stove, the temperature of the cold air is increased, which also increases the temperature of the hot air. This device has a simple structure, low cost, and is easy to modify, solving the problems of existing technologies that cannot recover all the residual hot air from the hot blast stove and the problem of unstable blast air pressure in blast furnace 40.

[0038] In this disclosure, the control method for switching the hot blast stove from the air supply mode to the combustion mode in the blast furnace waste heat blast recovery and pressure stabilization air supply device is as follows:

[0039] When the hot blast stove needs to stop supplying air and switch to combustion mode, the hot air valve 21 and the cold air valve 11 begin to close until they are completely closed and the air supply stops. At this time, the waste hot air in the hot blast stove 20 needs to be extracted to pressurize the high-pressure storage tank 70. At this time, the equalizing branch valve 72 opens, the air compressor 50 starts, and the gas ejector valve 62, the outlet ejector valve 63, and the inlet ejector valve 61 open in sequence. The waste hot air in the hot blast stove is extracted into the high-pressure gas storage tank 70 by the ejector 60.

[0040] When the pressure inside the hot blast stove is reduced to 0 kPa, the high-temperature, high-pressure waste heat air inside the stove is completely recovered. After closing the equalizing valve 72, the outlet ejector valve 63, the gas ejector valve 62, and the inlet ejector valve 61 are closed, and the air compressor 50 is shut down. The gas valve, combustion air valve, and exhaust gas valve on the hot blast stove are then opened, allowing the hot blast stove to switch from the air supply mode to the combustion mode.

[0041] In this way, the air compressor 50 and ejector 60 recover all the waste heat air from the stopped hot blast stove into the high-pressure air storage tank 70, realizing the recovery of all the waste heat air from the hot blast stove, improving the recovery efficiency and reducing the fuel ratio. Furthermore, the use of the ejector 60 ensures both the recovery of high-temperature gas and that the operating pressure is higher than the blower pressure, thus guaranteeing safe and efficient operation of the entire process.

[0042] Furthermore, the extraction time of waste hot air in the hot blast stove is less than or equal to the time when the hot blast stove switches from the air supply mode to the combustion mode. This allows for the complete recovery of waste hot air without affecting the operation mode of the existing hot blast stove. It is convenient to use and easy to assemble and modify with other structures.

[0043] In one embodiment provided in this disclosure, the control method for switching the hot blast stove from combustion mode to air supply mode in the blast furnace waste heat blast recovery and pressure stabilization air supply device is as follows:

[0044] When the hot blast stove needs to switch from combustion mode to air supply mode, close the gas valve, combustion air valve and exhaust gas valve on the hot blast stove to stop combustion; before supplying air, open the equalizing branch valve 72 and the equalizing main valve 71 in sequence.

[0045] High-pressure waste heat air in high-pressure storage tank 70 pressurizes the hot blast furnace 20. When the pressure inside the hot blast furnace reaches the air supply pressure, the equalizing branch valve 72 and the equalizing main valve 71 are closed. At this time, the pressure inside the hot blast furnace is the same as the pressure in the cold air main pipe and the hot air main pipe. The pressure inside the hot blast furnace reaches the air supply pressure, and the pressurization is completed. The equalizing operation of the hot blast furnace air supply is realized. At this time, the hot blast furnace has the conditions for stable pressure air supply.

[0046] Open the hot air valve 21 and cold air valve 11 on the hot air furnace, and the hot air furnace will switch from combustion mode to air supply mode.

[0047] In this way, the hot blast stove, which will switch from combustion mode to blast mode, is pressurized in advance without affecting the normal blast supply of blast furnace 40. Thus, the recovered high-temperature waste heat air is injected into the hot blast stove, which will switch from combustion mode to blast mode, to pressurize the hot blast stove to the blast pressure, utilizing heat and stabilizing the blast pressure of blast furnace 40.

[0048] Furthermore, in the blast furnace waste heat blast recovery and pressure stabilization air supply device, the hot blast stove is pressurized in advance before air supply, so that the hot blast stove can smoothly transition from combustion mode to air supply mode.

[0049] It should be noted that the present invention is not limited to the optional embodiments described above, and anyone can derive other various forms of products under the guidance of the present invention. The specific embodiments described above should not be construed as limiting the scope of protection of the present invention, which should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A blast furnace waste heat blast recovery and pressure stabilization air supply device, comprising at least three hot blast stoves, the hot blast stoves being communicatively connected via a controller, the controller being used to alternately configure one of the hot blast stoves as the air supply stove and the other hot blast stoves as combustion stoves, characterized in that... Each hot blast stove is equipped with hot blast branch pipes and cold blast branch pipes. Multiple hot blast branch pipes are connected to a hot blast main pipe, which is connected to the blast furnace. Each hot blast branch pipe is equipped with a hot blast valve. Multiple cold blast branch pipes are connected to a cold blast main pipe, which is connected to a blower. Each cold blast branch pipe is equipped with a cold blast valve. The blast furnace waste heat blast recovery and pressure stabilization air supply device also includes an ejector, an air compressor and a high-pressure air storage tank. The high-pressure gas storage tank has an inlet and an outlet. The inlet is connected to a pressurization pipe, which is equipped with a pressurization valve. The outlet is connected to a pressure equalization main pipe, which is equipped with a pressure equalization main valve. The ejector is provided with an inlet ejector tube, an outlet ejector tube, and a gas ejector tube, wherein the inlet ejector tube is connected to the equalizing main pipe; the equalizing main pipe is provided with at least three equalizing branch pipes, each of the equalizing branch pipes being connected to the cold air branch pipe in a one-to-one correspondence; each equalizing branch pipe is provided with an equalizing branch valve; the inlet ejector tube is also provided with an inlet ejector valve; The gas ejector tube is connected to the air compressor, and a gas ejector valve is provided on the gas ejector tube; wherein, the air compressor is provided with an air pipe connected to the atmosphere, and a filter is provided on the air pipe; The outlet ejector tube is connected to the pressurization tube, and the outlet ejector tube is provided with an outlet ejector valve; The controller is communicatively connected to the cold air valve, hot air valve, pressurization valve, inlet ejector valve, gas ejector valve, outlet ejector valve, equalizing main valve, equalizing branch valve, and air compressor. The controller controls the opening and closing of each valve and the start and stop of the air compressor accordingly, so as to alternately switch one of the hot air furnaces from the air supply mode to the combustion mode. In the combustion mode, the hot air furnace is a combustion furnace; in the air supply mode, the hot air furnace is an air supply furnace.

2. The blast furnace waste heat blast recovery and pressure stabilization air supply device according to claim 1, characterized in that, The method for switching the hot blast stove to combustion mode includes: Close the hot air valve and cold air valve of the hot air furnace; extract the waste hot air in the hot air furnace to pressurize the high-pressure storage tank, open the equalizing branch valve, start the air compressor, and open the gas ejector valve, outlet ejector valve and inlet ejector valve in sequence, so that the waste hot air in the hot air furnace is extracted into the high-pressure storage tank by the ejector. When the high-temperature and high-pressure waste heat air in the hot blast stove is completely recovered, the equalizing branch valve is closed, the outlet ejector valve, the gas ejector valve and the inlet ejector valve are closed, and the air compressor is turned off; the gas valve, the combustion air valve and the exhaust gas valve on the hot blast stove are opened, and the hot blast stove enters the combustion mode.

3. The blast furnace waste heat blast recovery and pressure stabilization air supply device according to claim 2, characterized in that, The extraction time of the waste hot air in the hot blast stove is less than or equal to the time it takes for the hot blast stove to switch from the air supply mode to the combustion mode.

4. The blast furnace waste heat blast recovery and pressure stabilization air supply device according to claim 1, characterized in that, In the blast furnace waste heat blast recovery and pressure stabilization air supply device, the control method for switching the hot blast stove from combustion mode to air supply mode is as follows: When the hot air furnace needs to be switched from combustion mode to air supply mode, the gas valve, combustion air valve and exhaust gas valve on the hot air furnace shall be closed to stop combustion; before air supply, the equalizing branch valve and the equalizing main valve shall be opened in sequence. High-pressure waste heat air in the high-pressure storage tank pressurizes the hot air furnace. When the pressure inside the hot air furnace reaches the air supply pressure value, the equalizing branch valve and the equalizing main valve are closed. At this time, the pressure inside the hot air furnace is the same as the pressure of the cold air main pipe and the pressure of the hot air main pipe. The pressure inside the hot air furnace reaches the air supply pressure, and the pressurization is completed. Gradually open the cold air valve and hot air valve on the hot air furnace, and the hot air furnace will switch from combustion mode to air supply mode.

5. The blast furnace waste heat blast recovery and pressure stabilization air supply device according to claim 4, characterized in that, In the blast furnace waste heat blast recovery and pressure stabilization air supply device, the hot blast stove is pressurized in advance before air supply.

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