Top combustion type hot blast stove system and combustion control method thereof

Abstract

The invention discloses a top combustion type hot blast stove system and a combustion control method thereof. The top combustion type hot blast stove system comprises two hot blast stoves. Each hot blast stove is connected with a coal gas branch pipe, a combustion-supporting gas branch pipe, a hot blast branch pipe and a waste gas branch pipe, and a stop valve, a surge tank and a coal gas inlet valve are arranged on each coal gas branch pipe; a cold air valve is arranged on the combustion-supporting gas branch pipe; a hot air valve is arranged on the hot air branch pipe; a blow-off valve is arranged on the waste gas branch pipe; the two hot-blast stoves can alternately and circularly run, and the continuous working time of each hot-blast stove in the stable combustion stage is not greater than the preset working time. The hot-blast stove is easy to replace, instant cut-off or gas supply of pressure gas can be avoided during the period of starting burning, stopping burning and replacing the hot-blast stove, rapid heat dissipation can be achieved when the working state of the hot-blast stove needs to be stopped immediately in emergency, and the service life of the hot-blast stove is effectively prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of hot blast furnaces in the metallurgical industry, and in particular to a top-burning hot blast furnace system and a combustion control method thereof. Background Art

[0002] A hot blast furnace is a device that provides hot air to a blast furnace to ensure the normal smelting of the blast furnace. There are three main types of hot blast furnaces: internal combustion, external combustion and top combustion. Among them, the top combustion hot blast furnace is divided into three types according to the layout of the pre-combustion chamber (burner): top-mounted, side-mounted and bottom-mounted. The top-mounted top-combustion hot blast furnace has gradually become the mainstream furnace type due to its stable structure, high wind temperature, long life and low investment. At present, the mainstream burner of the top-combustion hot blast furnace generally has an air ring and a gas ring. The gas ring is located at the upper part of the burner and is designed with multiple rotary gas nozzles; the air ring is located at the lower part of the burner and is designed with multiple direct air nozzles. The main problem with this design is that the residual gas in the burner cannot be purged clean after the furnace is burned, resulting in residual gas. The residual gas includes the dead zone of the upper vault of the combustion chamber and the gas ring. The residual gas mixes with the high-temperature oxygen-rich hot air during the air supply stage of the hot blast furnace, causing the burner to deflagrate and detonate, causing damage to the burner masonry. At the same time, a single hot blast furnace cannot work uninterruptedly during continuous production. During continuous operation, multiple hot blast furnaces need to cooperate with each other to complete the operation.

[0003] In some designs of the prior art, there is only one hot air furnace in the combustion control method, which can only be stopped by emergency shutdown in case of emergency, which has a great impact on the life of the hot air furnace. In some other designs, although multiple hot air furnaces are set, it is too cumbersome to switch between multiple hot air furnaces after reaching the system preset value; when an emergency occurs and the working state of the hot air furnace needs to be stopped immediately, the system cannot quickly dissipate heat. In addition, in the existing hot air furnace, the speed of the upward movement of the coal gas in the inner cavity channel behind the coal gas inlet is too low, resulting in uneven gas mixing, increasing the generation of nitrogen oxides, and affecting the combustion efficiency. Summary of the invention

[0004] The object of the present invention is to provide a top-burning hot blast stove system and a combustion control method thereof, wherein the stove changing operation is simple, and the instantaneous cutting off or supply of pressurized gas can be avoided during the starting and stopping of stove burning and stove changing, and rapid heat dissipation can be achieved when the working state of the hot blast stove needs to be stopped immediately in an emergency, thereby effectively prolonging the service life of the hot blast stove.

[0005] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0006] The present invention provides a top-burning hot blast furnace system, comprising two hot blast furnaces; each hot blast furnace is connected with a gas branch pipe, a combustion-supporting gas branch pipe, a hot blast branch pipe and an exhaust gas branch pipe, the gas branch pipe is used to introduce gas into the hot blast furnace, and a cut-off valve, a pressure-stabilizing tank and a gas inlet valve are sequentially arranged on the gas branch pipe along the gas conveying direction; the combustion-supporting gas branch pipe is used to introduce combustion-supporting gas into the hot blast furnace, and a cold air valve is arranged on the combustion-supporting gas branch pipe; the hot blast branch pipe is used to introduce the generated hot gas into the blast furnace, and a hot air valve is arranged on the hot blast branch pipe; The exhaust gas branch pipe is used to pass the generated exhaust gas into the waste heat boiler, and a vent valve is provided on the exhaust gas branch pipe; the two hot blast furnaces can operate alternately and cyclically, and the continuous working time of each hot blast furnace in the stable combustion stage is not more than the preset working time; when switching from one hot blast furnace to another, first close the shut-off valve corresponding to one of the hot blast furnaces and open the shut-off valve corresponding to the other hot blast furnace at the same time, and then gradually close the gas inlet valve corresponding to one of the hot blast furnaces and gradually close the corresponding cold air valve simultaneously.

[0007] In a preferred embodiment of the present invention, a gas flow meter is provided on the gas branch pipe near the hot blast stove, a combustion-supporting gas flow meter is provided on the combustion-supporting gas branch pipe near the hot blast stove, and a hot air flow meter is provided on the hot air branch pipe near the hot blast stove; a temperature detector is provided on the hot blast stove for detecting the dome temperature of the hot blast stove.

[0008] In a preferred embodiment of the present invention, the top-fired hot air furnace system also includes a control device, which is electrically connected to the shut-off valve, gas inlet valve, gas flow meter, cold air valve, combustion air flow meter, hot air valve, hot air flow meter, vent valve and temperature detector.

[0009] In a preferred embodiment of the present invention, the pressure-stabilizing tank includes an external shell, a gas storage airbag and a pressure monitoring device. The gas storage airbag is arranged in the external shell, and the pressure monitoring device can monitor the pressure in the gas storage airbag; an air inlet interface and an air outlet interface are provided on the gas storage airbag, and the air inlet interface and the air outlet interface are used to be connected in series to the gas branch pipe.

[0010] In a preferred embodiment of the present invention, the pressure stabilizing tank further comprises a tightening mechanism, which can tighten the gas storage airbag to adjust the volume in the gas storage airbag connected to the gas branch pipe.

[0011] In a preferred embodiment of the present invention, the hot blast furnace includes a furnace body with a dome on the top, a combustion cavity is formed in the upper part of the furnace body, and a gas ring channel structure and a combustion-supporting gas ring channel structure are provided in the upper side wall of the furnace body at upper and lower intervals. The gas ring channel structure can form a coal gas swirling airflow downward in the combustion cavity, and the combustion-supporting gas ring channel structure can form a combustion-supporting gas swirling airflow upward in the combustion cavity, and the swirling flow directions of the coal gas swirling airflow and the combustion-supporting gas swirling airflow are opposite.

[0012] In a preferred embodiment of the present invention, the gas annular channel structure includes a gas inlet channel, a gas annular channel, and multiple groups of gas diversion channels and multiple groups of gas injection structures arranged alternately in a circumferential direction. The gas inlet channel is tangent to the gas annular channel and is used to connect the corresponding gas branch pipes. Each group of gas injection structures includes at least two groups of gas injection components arranged at intervals in the circumferential direction. Each group of gas injection components includes an upper gas channel and a lower gas channel arranged at intervals in the upper and lower directions. The upper gas channel includes a first upper horizontal gas channel and an upper inclined gas channel connected in sequence from the outside to the inside, and the outer end of the first upper horizontal gas channel is connected to the gas annular channel, and the inner end of the upper inclined gas channel is connected to the combustion cavity. The upper inclined gas channel is arranged obliquely downward from the first upper horizontal gas channel to the combustion cavity. The lower gas channel includes a first upper horizontal gas channel and an upper inclined gas channel connected in sequence from the outside to the inside. The lower horizontal gas channel and the lower inclined gas channel, the outer end of the first lower horizontal gas channel is connected to the gas ring channel, the inner end of the lower inclined gas channel is connected to the combustion cavity, and the lower inclined gas channel is arranged obliquely upward from the first lower horizontal gas channel to the combustion cavity; the axes of the first upper horizontal gas channel and the first lower horizontal gas channel extend along the corresponding radial direction in the gas ring channel; each group of gas diversion channels includes the second upper horizontal gas channel, the middle inclined gas channel and the second lower horizontal gas channel connected in sequence from the outside to the inside, the axis of the second upper horizontal gas channel is parallel to the axis of the second lower horizontal gas channel, and the axis of the second upper horizontal gas channel is inclined relative to the corresponding radial direction in the gas ring channel toward the annular airflow direction of the gas ring channel, and the axis of the middle inclined gas channel is inclined downward from the outer wall of the furnace body to the combustion cavity.

[0013] In a preferred embodiment of the present invention, the combustion gas annular channel structure includes a combustion gas inlet channel, a combustion gas annular channel, and multiple groups of combustion gas diversion channels and multiple groups of combustion gas jet structures arranged alternately in circumferential order, the combustion gas inlet channel is tangent to the combustion gas annular channel and is used to connect the corresponding combustion gas branch pipe; each group of combustion gas jet structures includes at least two groups of combustion gas jet assemblies arranged at intervals in the circumferential direction, each group of combustion gas jet assemblies includes an upper combustion gas channel and a lower combustion gas channel arranged at intervals in the upper and lower directions, the upper combustion gas channel includes a first upper horizontal combustion gas channel and an upper inclined combustion gas channel connected in sequence from the outside to the inside, and the outer end portion of the first upper horizontal combustion gas channel is connected to the combustion gas annular channel, the inner end portion of the upper inclined combustion gas channel is connected to the combustion inner cavity, and the upper inclined combustion gas channel is arranged obliquely downward from the first upper horizontal combustion gas channel to the combustion inner cavity; the lower combustion gas channel includes a first upper horizontal combustion gas channel and an upper inclined combustion gas channel connected in sequence from the outside to the inside A lower horizontal fuel gas-supporting gas channel and a lower inclined fuel gas-supporting gas channel, the outer end portion of the first lower horizontal fuel gas-supporting gas channel is connected to the fuel gas-supporting gas ring channel, the inner end portion of the lower inclined fuel gas-supporting gas channel is connected to the combustion cavity, and the lower inclined fuel gas-supporting gas channel is arranged obliquely upward from the first lower horizontal fuel gas-supporting gas channel to the combustion cavity; the axes of the first upper horizontal fuel gas-supporting gas channel and the first lower horizontal fuel gas-supporting gas channel both extend along the corresponding radial direction in the fuel gas-supporting gas ring channel; each group of fuel gas diversion channels includes a second lower horizontal fuel gas-supporting gas channel, a middle inclined fuel gas-supporting gas channel and a second upper horizontal fuel gas-supporting gas channel connected in sequence from the outside to the inside, the axis of the second lower horizontal fuel gas-supporting gas channel is parallel to the axis of the second upper horizontal fuel gas-supporting gas channel, and the axis of the second lower horizontal fuel gas-supporting gas channel is inclined relative to the corresponding radial direction in the fuel gas ring channel toward the annular airflow direction of the fuel gas ring channel, and the axis of the middle inclined fuel gas channel is inclined upward from the outer wall of the furnace body to the combustion cavity.

[0014] The present invention also provides a combustion control method for the top-fired hot blast stove system, comprising:

[0015] One of the hot blast furnaces is used as a working furnace, and the other hot blast furnace is used as a dormant furnace;

[0016] Open the shut-off valve corresponding to the working furnace and deliver the gas to the pressure-stabilizing tank corresponding to the working furnace;

[0017] When the pressure in the pressure regulating tank reaches the preset pressure value, the working furnace is operated; operating the working furnace includes:

[0018] Open the corresponding gas inlet valve to deliver the gas to the working furnace, and open the corresponding cold air valve to introduce the combustion-supporting gas into the working furnace to adjust the dome temperature of the working furnace until the working furnace is in a stable combustion stage;

[0019] In the stable combustion stage, when the continuous working time of the working furnace in the stable combustion stage reaches the preset working time, the shut-off valve of the working furnace is closed and the shut-off valve of the dormant furnace is opened at the same time, and then the gas inlet valve corresponding to the working furnace is gradually closed and the corresponding cold air valve is gradually closed synchronously until the gas inlet valve is completely closed and the working furnace is in the heat storage stage; cold air is introduced into the working furnace, and the working furnace forms hot air after heat exchange with the cold air, and the generated hot air is introduced into the blast furnace;

[0020] The working furnace is switched to a new dormant furnace. When the pressure in the pressure regulating tank corresponding to the dormant furnace reaches a preset pressure value, the steps of operating the working furnace are repeated for the dormant furnace to switch the old dormant furnace to the new working furnace.

[0021] In a preferred embodiment of the present invention, operating the working furnace further comprises:

[0022] Real-time detection of the dome temperature in the working furnace, and comparison of the dome temperature in the working furnace with a preset dome temperature upper limit;

[0023] Before the working furnace enters the stable combustion stage, if the dome temperature in the working furnace is lower than the preset dome temperature upper limit and the difference between the two is greater than the preset difference, then according to the dome temperature in the working furnace, the gas flow at the gas inlet valve and the preset optimal air-fuel ratio, the gas flow and the combustion-supporting gas flow into the working furnace are adjusted so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference;

[0024] After the working furnace enters the stable combustion stage, if the dome temperature in the working furnace exceeds the preset dome temperature upper limit, the gas flow into the working furnace is adjusted so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference.

[0025] In a preferred embodiment of the present invention, the step of operating the working furnace further comprises:

[0026] During the stable combustion stage, when the dome temperature of the working furnace is higher than the preset dome temperature upper limit by a difference greater than the preset difference, the shut-off valve of the working furnace is closed and the vent valve of the working furnace and the shut-off valve of the dormant furnace are opened at the same time, and then the gas inlet valve corresponding to the working furnace is gradually closed and the corresponding cold air valve is gradually closed synchronously until the gas inlet valve is completely closed.

[0027] In a preferred embodiment of the present invention, the preset optimal air-fuel ratio is 0.6-0.8, and the preset upper limit value of the dome temperature is 1300-1500°C.

[0028] As described above, the present invention is provided with two hot blast furnaces, which can be operated alternately, and the furnace replacement operation is simple, and the continuous working time of each hot blast furnace in the stable combustion stage is controlled within the preset working time, thereby increasing the service life of the hot blast furnace. By setting a pressure stabilizing tank, the coal gas first enters the pressure stabilizing tank before entering the hot blast furnace, effectively ensuring the stable pressure change of the hot blast furnace during the start of furnace burning, stop of furnace burning and furnace replacement; when starting furnace burning, the corresponding coal gas inlet valve can be gradually opened to allow the coal gas to pass into the hot blast furnace more smoothly; when changing furnaces, the shut-off valve of the current working furnace is first closed, and then the corresponding coal gas inlet valve and cold air valve are gradually closed, so that the coal gas can be gradually cut off; thereby effectively avoiding the instantaneous shut-off or gas supply caused by the hot blast furnace replacement, and changing the existing cliff-like rigid change when the coal gas is cut off or supplied into a flexible gradual change process, greatly improving the combustion efficiency and reducing the loss of the hot blast furnace. When one of the hot blast furnaces encounters an emergency and needs to be stopped urgently, first close the shut-off valve corresponding to the hot blast furnace, and gradually cut off the gas. At the same time, open the corresponding relief valve to quickly reduce the pressure in the hot blast furnace, achieve rapid heat dissipation, and ensure safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0030] in:

[0031] Figure 1 This is a schematic structural diagram of a top-fired hot blast stove system provided by the present invention.

[0032] Figure 2 A partial front view of the hot blast stove provided by the present invention.

[0033] Figure 3 A schematic top view of the hot blast stove provided by the present invention at the gas ring structure.

[0034] Figure 4 A schematic top view of the hot blast stove provided by the present invention at the combustion-aiding gas ring structure.

[0035] Figure 5 This is a schematic structural diagram of the upper gas channel and the lower gas channel provided by the present invention.

[0036] Figure 6 This is a schematic structural diagram of the gas diversion channel provided by the present invention.

[0037] Description of Figure Numbers:

[0038] 1. Hot blast furnace; 11. Furnace body; 12. Combustion cavity; 13. Gas ring structure; 131. Gas inlet channel; 132. Gas ring; 133. Upper gas channel; 1331. First upper horizontal gas channel; 1332. Upper inclined gas channel; 134. Lower gas channel; 1341. First lower horizontal gas channel; 1342. Lower inclined gas channel; 135. Gas diversion channel; 1351. Second upper horizontal gas channel; 1352. Middle inclined gas channel; 1353. Second lower horizontal gas channel; 14. Combustion gas ring structure; 141. Combustion gas inlet channel; 142. Combustion gas ring; 143. Upper combustion gas channel; 144. Lower combustion gas channel; 145. Combustion gas diversion channel;

[0039] 2. Gas branch pipe; 21. Shut-off valve; 22. Pressure regulating tank; 23. Gas inlet valve; 24. Gas flow meter;

[0040] 3. Fuel-supporting gas branch pipe; 31. Cold air valve; 32. Fuel-supporting gas flow meter;

[0041] 4. Hot air branch pipe; 41. Hot air flow meter; 42. Hot air valve;

[0042] 5. Exhaust gas branch pipe; 51. Release valve;

[0043] 6. Gas tank; 61. Gas main;

[0044] 7. Gas storage tank; 71. Fuel-supporting gas main pipe;

[0045] 8. Blast furnace; 81. Hot air main;

[0046] 9. Waste heat boiler; 91. Waste gas main. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0048] like Figures 1 to 6As shown, this embodiment provides a top-burning hot blast furnace system, including two hot blast furnaces 1; each hot blast furnace 1 is connected with a gas branch pipe 2, a combustion-supporting gas branch pipe 3, a hot blast branch pipe 4 and an exhaust gas branch pipe 5, the gas branch pipe 2 is used to introduce gas into the hot blast furnace 1, and a cut-off valve 21, a pressure-stabilizing tank 22 and a gas inlet valve 23 are sequentially arranged on the gas branch pipe 2 along the gas delivery direction; the combustion-supporting gas branch pipe 3 is used to introduce combustion-supporting gas into the hot blast furnace 1, and a cold air valve 31 is arranged on the combustion-supporting gas branch pipe 3; the hot blast branch pipe 4 is used to introduce the generated hot gas into the blast furnace 8, and a hot blast valve 31 is arranged on the hot blast branch pipe 4 valve 42; the exhaust gas branch pipe 5 is used to pass the generated exhaust gas into the waste heat boiler 9, and a vent valve 51 is provided on the exhaust gas branch pipe 5; the two hot blast furnaces 1 can be operated alternately and cyclically, and the continuous working time of each hot blast furnace 1 in the stable combustion stage is not greater than the preset working time; when switching one of the hot blast furnaces 1 to another hot blast furnace 1, first close the shut-off valve 21 corresponding to one of the hot blast furnaces 1 and open the shut-off valve 21 corresponding to the other hot blast furnace 1 at the same time, and then gradually close the gas inlet valve 23 corresponding to one of the hot blast furnaces 1 and gradually close the corresponding cold air valve 31 synchronously.

[0049] Generally, two gas branch pipes 2 can be connected to gas cabinet 6, two combustion-supporting gas branch pipes 3 can be connected to gas storage tank 7, two hot air branch pipes 4 can be connected to blast furnace 8, two waste gas branch pipes 5 can be connected to waste heat boiler 9. Alternatively, two gas branch pipes 2 can be connected to gas cabinet 6, two combustion-supporting gas branch pipes 3 can be connected to gas storage tank 7, two hot air branch pipes 4 can be connected to blast furnace 8, two waste gas branch pipes 5 can be connected to waste heat boiler 9. Figure 1 The two gas branch pipes 2 shown in the figure are connected to the gas cabinet 6 through a gas main pipe 61, the two combustion-supporting gas branch pipes 3 are connected to the gas storage tank 7 through a combustion-supporting gas main pipe 71, the two hot gas branch pipes are connected to the blast furnace 8 through a hot blast main pipe 81, and the two waste gas branch pipes 5 are connected to the waste gas boiler through a waste gas main pipe 91. The combustion-supporting gas includes but is not limited to air and oxygen suitable for combustion. In this embodiment, the combustion-supporting gas is preferably air.

[0050] When in use, the two hot blast furnaces 1 are switched to operate alternately, one as a working furnace and the other as a dormant furnace. The gas holder 6 is mainly used to supply combustion raw materials to the hot blast furnace 1, and the gas storage tank 7 is used to supply combustion-supporting gas to the hot blast furnace 1. For the working furnace, after the gas is generated from the gas holder 6, it first enters the buffering pressure-stabilizing tank 22 through the gas branch pipe 2. After the gas is buffered in the pressure-stabilizing tank 22 to stabilize the pressure, it enters the hot blast furnace 1 steadily and smoothly through the gas outlet valve to start the furnace burning process. The air enters the hot blast furnace 1 from the gas storage tank 7 through the combustion-supporting gas branch pipe 3. When the working time of the working furnace in the stable combustion stage reaches the preset working time, it is necessary to switch the two hot blast furnaces 1 to realize the furnace change, close the shut-off valve 21 of the current working furnace and open the shut-off valve 21 of the current dormant furnace at the same time, and then gradually close the gas inlet valve 23 corresponding to the working furnace, and synchronously gradually close the corresponding cold air valve 31 to gradually cut off the gas to the working furnace; after that, the working furnace enters the heat storage period, and the introduced cold air is heat-exchanged to form hot air and introduced into the blast furnace 8; after the hot air is supplied to the blast furnace 8, the working furnace is switched to a new dormant furnace, and the corresponding gas inlet valve 23 is opened after the pressure in the pressure-stabilizing tank 22 of the dormant furnace reaches the preset pressure value, so as to switch the dormant furnace to the new working furnace and repeat the furnace burning process.

[0051] Therefore, the top-burning hot blast furnace system in the present application is provided with two hot blast furnaces 1, which can be operated alternately, and the furnace replacement operation is simple, and the continuous working time of each hot blast furnace 1 in the stable combustion stage is controlled within the preset working time, thereby improving the service life of the hot blast furnace 1. By setting a pressure stabilizing tank 22, before the coal gas enters the hot blast furnace 1, it first enters the pressure stabilizing tank 22, effectively ensuring the stable pressure change of the hot blast furnace 1 during the start of furnace burning, stop of furnace burning and furnace replacement; when starting furnace burning, the corresponding coal gas inlet valve 23 can be gradually opened to allow the coal gas to pass into the hot blast furnace 1 more smoothly; when changing furnaces, the cut-off valve 21 of the current working furnace is first closed, and then the corresponding coal gas inlet valve 23 and the cold air valve 31 are gradually closed, so that the coal gas can be gradually cut off; thereby effectively avoiding the instantaneous cut-off or gas supply of coal gas caused by the hot blast furnace 1 changing furnaces, and changing the existing cliff-like rigid change when the coal gas is cut off or supplied into a flexible gradual change process, greatly improving the combustion efficiency and reducing the loss of the hot blast furnace 1. When one of the hot blast furnaces 1 encounters an emergency and needs to be stopped urgently, the shut-off valve 21 corresponding to the hot blast furnace 1 is closed first, and the gas is gradually cut off. At the same time, the corresponding relief valve 51 can be opened to quickly reduce the pressure in the hot blast furnace 1, achieve rapid heat dissipation, and ensure safety.

[0052] In a specific implementation, a gas flow meter 24 is provided on the gas branch pipe 2 and near the hot blast stove 1, a gas flow meter 32 is provided on the combustion-supporting gas branch pipe 3 and near the hot blast stove 1, and a hot blast flow meter 41 is provided on the hot blast branch pipe 4 and near the hot blast stove 1, so as to detect the gas flow, combustion-supporting gas flow or hot blast flow at various locations. A temperature detector is provided on the hot blast stove 1 to detect the dome temperature of the hot blast stove 1.

[0053] In actual applications, the top-fired hot air furnace system also includes a control device, which is electrically connected to the shut-off valve 21, the gas inlet valve 23, the gas flow meter 24, the cold air valve 31, the combustion gas flow meter 32, the hot air valve 42, the hot air flow meter 41, the vent valve 51 and the temperature detector.

[0054] The above-mentioned shut-off valve 21 has a quick shut-off function, and the above-mentioned gas inlet valve 23 and cold air valve 31 are both flow valves, and the flow rate of the gas flow can be adjusted by adjusting the opening. The gas flowmeter 24 is used to detect the gas flow rate sent to the hot blast furnace 1. The cold air valve 31 is used to control the input rate of the combustion-supporting gas, and the combustion-supporting gas flowmeter 32 is used to detect the total input amount of the combustion-supporting gas. By adjusting the input amount of the combustion-supporting gas, the oxygen concentration of the mixed gas is ensured, thereby maintaining the mixed gas in the hot blast furnace 1. The combustion is fully maintained and the emission of pollutants is reduced. Generally, the hot air valve 42 and the vent valve 51 are also provided with a pressure gauge and a thermometer, and the cold air valve 31 is provided with a pressure gauge, and the control device is also electrically connected to these thermometers and pressure gauges.

[0055] The control device can realize automatic control and adjustment, and can solve the problem that the existing manual control is prone to physical objects. The control device adjusts the opening of the gas inlet valve 23 and / or the cold air valve 31 to adjust the gas flow and air flow, so that the amount of gas and air meets the preset optimal air-fuel ratio; before the working furnace enters the stable combustion stage, the gas flow and the combustion-supporting gas flow into the working furnace can be adjusted according to the dome temperature in the working furnace, the gas flow at the gas inlet valve 23 and the preset optimal air-fuel ratio, so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference; after the working furnace enters the stable combustion stage, the opening of the gas inlet valve 23 can be adjusted according to the dome temperature detected by the temperature detector and the preset dome temperature upper limit, so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference.

[0056] Furthermore, the pressure-stabilizing tank 22 includes an external shell, a gas storage airbag and a pressure monitoring device. The gas storage airbag is arranged in the external shell, and the pressure monitoring device can monitor the pressure in the gas storage airbag; an air inlet interface and an air outlet interface are provided on the gas storage airbag, and the air inlet interface and the air outlet interface are used to be connected in series to the gas branch pipe 2.

[0057] The outer shell mainly supports and protects the gas storage airbag, and a frame structure can be used. The outer shell is generally cylindrical in shape, with a rigid structure and a wall thickness of 10-15mm. The gas storage airbag is made of abrasion-resistant nitrile rubber (NBR). The overall shape of the airbag is also cylindrical, with a diameter that is two-thirds of the diameter of the outer shell. The air inlet and outlet interfaces on the gas storage airbag are generally located at the same level and are located one-fifth of the distance from the bottom of the airbag.

[0058] In this embodiment, the pressure stabilizing tank 22 further includes a tightening mechanism, which can tighten the gas storage airbag to adjust the volume of the gas storage airbag connected to the gas branch pipe 2.

[0059] The control device is electrically connected to the pressure monitoring device and the tightening mechanism. The tightening mechanism can adopt any structural form as long as it can tighten the designated position of the gas storage airbag to separate the inner cavity of the gas storage airbag into two completely independent chambers, thereby changing the volume of the chamber connected to the gas branch pipe 2.

[0060] When the whole system is operating normally, the tightening mechanism tightens the gas storage bag, but it should be ensured that the volume of the chamber in the gas storage bag connected to the gas branch pipe 2 can meet the use requirements.

[0061] When the pressure monitoring device on the pressure-stabilizing tank 22 detects that the pressure in the gas storage airbag exceeds the preset value and an abnormality occurs, the tightening mechanism will loosen the gas storage airbag, so that the entire chamber in the gas storage airbag is connected to the gas branch pipe 2, so as to increase the volume of the chamber in the gas storage airbag connected to the gas branch pipe 2 and improve safety. Generally, the abnormal pressure in the gas storage airbag in the pressure-stabilizing tank 22 is mainly caused by the following two aspects: on the one hand, it is due to the abnormality of the pressure-stabilizing tank 22 itself; on the other hand, it is due to the abnormality of one of the hot blast furnaces 1. At this time, when the shut-off valve 21 of the abnormal hot blast furnace 1 is cut off and the shut-off valve 21 of another hot blast furnace 1 is opened at the same time, the pressure in the pressure-stabilizing tank 22 corresponding to the other hot blast furnace 1 may suddenly become too high. At this time, the gas storage airbag is loosened by the tightening mechanism to reduce the pressure to ensure the stability of the flow delivered to the other hot blast furnace 1.

[0062] Furthermore, the hot blast furnace 1 includes a furnace body 11 with a dome on the top, and a combustion chamber 12 is formed in the upper part of the furnace body 11. A gas ring structure 13 and a combustion-supporting gas ring structure 14 are provided in the upper side wall of the furnace body 11 at intervals therebetween. The gas ring structure 13 can cause the coal gas to form a coal gas swirling airflow downward in the combustion chamber 12, and the combustion-supporting gas ring structure 14 can cause the combustion-supporting gas to form a combustion-supporting gas swirling airflow upward in the combustion chamber 12, and the swirling flow directions of the coal gas swirling airflow and the combustion-supporting gas swirling airflow are opposite to each other, so as to improve the mixing effect of the coal gas and the combustion-supporting gas.

[0063] More specifically, see Figures 2 to 6 The gas annular structure 13 includes a gas inlet channel 131, a gas annular channel 132, and a plurality of groups of gas diversion channels 135 and a plurality of groups of gas injection structures arranged alternately in a circumferential direction. The gas inlet channel 131 is tangent to the gas annular channel 132 and is used to connect the corresponding gas branch pipe 2. Each group of gas injection structures includes at least two groups of gas injection components arranged at intervals in the circumferential direction. Each group of gas injection components includes an upper gas channel 133 and a lower gas channel 134 arranged at intervals in the upper and lower directions. The upper gas channel 133 includes a first upper horizontal gas channel 1331 and an upper inclined gas channel 1332 connected in sequence from the outside to the inside. The outer end of the first upper horizontal gas channel 1331 is connected to the gas annular channel 132, and the inner end of the upper inclined gas channel 1332 is connected to the combustion cavity 12. The upper inclined gas channel 1332 is arranged obliquely downward from the first upper horizontal gas channel 1331 to the combustion cavity 12.

[0064] The lower gas channel 134 includes a first lower horizontal gas channel 1341 and a lower inclined gas channel 1342 which are sequentially connected from outside to inside. The outer end of the first lower horizontal gas channel 1341 is connected to the gas ring channel 132, and the inner end of the lower inclined gas channel 1342 is connected to the combustion chamber 12. The lower inclined gas channel 1342 is arranged obliquely upward from the first lower horizontal gas channel 1341 to the combustion chamber 12. The axes of the first upper horizontal gas channel 1331 and the first lower horizontal gas channel 1341 both extend along the corresponding radial direction in the gas ring channel 132. Each The group of gas diversion channels 135 includes a second upper horizontal gas channel 1351, a middle inclined gas channel 1352 and a second lower horizontal gas channel 1353 which are connected in sequence from the outside to the inside. The axis of the second upper horizontal gas channel 1351 is parallel to the axis of the second lower horizontal gas channel 1353, and the axis of the second upper horizontal gas channel 1351 is inclined relative to the corresponding radial direction of the gas ring channel 132 toward the annular airflow direction of the gas ring channel 132, and the axis of the middle inclined gas channel 1352 is inclined downward from the outer wall of the furnace body 11 to the combustion chamber 12.

[0065] The combustion-supporting gas annular channel structure 14 is similar to the coal gas annular channel structure 13, and the main difference is that the circulation directions of the airflows in the annular channels of the two are opposite, one is clockwise airflow and the other is counterclockwise airflow; and the inclination directions of the inclined channels in the diversion channels of the two are opposite. The details are as follows:

[0066] The combustion gas annular structure 14 includes a combustion gas inlet channel 141, a combustion gas annular channel 142, and multiple groups of combustion gas diversion channels 145 and multiple groups of combustion gas jet structures arranged alternately in circumferential order. The combustion gas inlet channel 141 is tangent to the combustion gas annular channel 142 and is used to connect the corresponding combustion gas branch pipe 3; each group of combustion gas jet structures includes at least two groups of combustion gas jet assemblies arranged at intervals in the circumferential direction, and each group of combustion gas jet assemblies includes an upper combustion gas channel 143 and a lower combustion gas channel 144 arranged at intervals in the upper and lower directions, and the upper combustion gas channel 143 includes a first upper horizontal combustion gas channel and an upper inclined combustion gas channel connected in sequence from the outside to the inside, and the outer end of the first upper horizontal combustion gas channel is connected to the combustion gas annular channel 142, and the inner end of the upper inclined combustion gas channel is connected to the combustion cavity 12, and the upper inclined combustion gas channel is arranged obliquely downward from the first upper horizontal combustion gas channel to the combustion cavity 12.

[0067] The lower combustion gas channel 144 includes a first lower horizontal combustion gas channel and a lower inclined combustion gas channel connected in sequence from outside to inside, the outer end of the first lower horizontal combustion gas channel is connected to the combustion gas annular channel 142, the inner end of the lower inclined combustion gas channel is connected to the combustion inner chamber 12, and the lower inclined combustion gas channel is arranged obliquely upward from the first lower horizontal combustion gas channel to the combustion inner chamber 12; the axes of the first upper horizontal combustion gas channel and the first lower horizontal combustion gas channel both extend along the corresponding radial direction in the combustion gas annular channel 142; each group of combustion gas diversion channels 145 includes a second lower horizontal combustion gas channel, a middle inclined combustion gas channel and a second upper horizontal combustion gas channel connected in sequence from outside to inside, the axis of the second lower horizontal combustion gas channel is parallel to the axis of the second upper horizontal combustion gas channel, and the axis of the second lower horizontal combustion gas channel is inclined relative to the corresponding radial direction in the combustion gas annular channel 142 toward the annular airflow direction of the combustion gas annular channel 142, and the axis of the middle inclined combustion gas channel is inclined upward from the outer wall of the furnace body 11 to the combustion inner chamber 12.

[0068] The outer contour of the furnace body 11 is generally an upright cylindrical structure, and a refractory lining is generally provided on the inner wall of the furnace body 11 and the portion corresponding to the combustion chamber 12 to prevent damage to the inner chamber wall. The outer ends of the gas inlet channel 131 and the combustion-supporting gas inlet channel 141 penetrate the outer wall of the furnace body 11 to connect the corresponding gas branch pipe 2 and the combustion-supporting gas branch pipe 3. The inner ends of the upper inclined gas channel 1332, the lower inclined gas channel 1342, the second lower horizontal gas channel 1353, the upper inclined combustion-supporting gas channel, the lower inclined combustion-supporting gas channel and the second upper horizontal combustion-supporting gas channel all penetrate the refractory lining of the inner wall of the furnace body 11 to communicate with the combustion chamber 12.

[0069] The gas annular channel 132 is a circular channel, and multiple groups of gas diversion channels 135 are evenly spaced in the circumferential direction. A group of gas injection structures is provided between two adjacent groups of gas diversion channels 135. Each group of gas injection structures includes at least two groups of gas injection components. For example, in this embodiment, each group of injection structures includes two groups of gas injection components. The upper gas channel 133 and the lower gas channel 134 in each group of gas injection components are not arranged vertically opposite to each other, but are staggered a little along the circumferential direction to match the inclined gas diversion channel 135; each first upper horizontal gas channel 1331 and each second upper horizontal gas channel 1351 should be located at the same height, and each first lower horizontal gas channel 1341 and each second lower horizontal gas channel 1353 should be located at the same height. The arrangement of each channel in the combustion-supporting gas annular channel structure 14 is similar to that of the gas annular channel structure 13. A burner is also provided on the furnace body 11 and between the gas ring structure 13 and the combustion-supporting gas ring structure 14. The gas inlet channel 131 and the combustion-supporting gas inlet channel 141 are preferably distributed on both sides of the burner, respectively, and the projections of the gas inlet channel 131 and the combustion-supporting gas inlet channel 141 on the same cross section of the furnace body 11 are centrally symmetrical about the center of the furnace body 11. The gas inlet channel 131 and the combustion-supporting gas inlet channel 141 are distributed at 180° from a top view.

[0070] The coal gas enters the gas ring channel 132 through the gas inlet channel 131. Part of the coal gas directly rushes into the gas ring channel 132 and then passes through the first upper horizontal gas channel 1331 and the first lower horizontal gas channel 1341, and then is sprayed into the combustion cavity 12 from the inner ports of the upper inclined gas channel 1332 and the lower inclined gas channel 1342 respectively. At the same time, most of the coal gas rushes into the combustion cavity 12 along the wall of the gas ring channel 132 through the second upper horizontal gas channel 1351, the middle inclined gas channel 1352 and the second lower horizontal gas channel 1353, and forms a downward swirling airflow at the upper part of the combustion cavity 12. At the same time, air enters the combustion-supporting gas ring channel 142 from the combustion-supporting gas inlet channel 141, and forms an upward swirling airflow in the middle of the combustion chamber 12 through a similar path. The swirling airflow of gas and air is fully mixed in the combustion chamber 12 and then burns. The heat is stored in the heat storage bricks of the furnace body 11 and waits for the air supply period to convert the cold air into hot air. The remaining exhaust gas enters the exhaust gas boiler through the exhaust gas channel at the bottom and the corresponding exhaust gas branch pipe 5 to complete the furnace burning process.

[0071] The design of the entire gas annular channel structure 13 can make the airflow quickly divided into two parts after entering from the gas inlet channel 131. One part of the airflow quickly enters the combustion cavity 12 through the upper inclined gas channel 1332 and the lower inclined gas channel 1342, so as not to lose much speed, so that the airflow is faster when it is ejected from the nozzle (i.e., the port) of the inclined gas channel, and a swirl can be formed more quickly. The other part of the airflow is ejected from each group of gas diversion channels 135 into the combustion cavity 12 to form a downward swirling airflow. The design of the entire combustion-supporting gas annular channel structure 14 also has the same advantages. It can further help the coal gas and the combustion-supporting gas to mix better, help improve the combustion efficiency, and make the combustion more complete. In addition, the inclined channels in each group of gas diversion channels 135 and each group of combustion-supporting gas diversion channels 145 are designed as inclined channels, which can increase the flow rate and be more conducive to the mixing of coal gas and combustion-supporting gas.

[0072] In this embodiment, the angles between the axis of the upper inclined gas channel 1332 and the axis of the upper inclined combustion-supporting gas channel and the horizontal plane are both 20-40°, and more preferably 30-35°; the angles between the axis of the lower inclined gas channel 1342 and the axis of the lower inclined combustion-supporting gas channel and the horizontal plane are both 20-40°, and more preferably 30-35°; the angles between the axis of the middle inclined gas channel 1352 and the axis of the middle inclined combustion-supporting gas channel and the vertical plane are both 15-35°, and more preferably 25-32°. The inclination angles of each inclined channel can be determined according to actual needs, and this embodiment is only for illustrative purposes.

[0073] Furthermore, the present application also provides a combustion control method for the top-fired hot blast stove system, comprising:

[0074] One of the hot blast furnaces 1 is used as a working furnace, and the other hot blast furnace 1 is used as a dormant furnace;

[0075] Open the cut-off valve 21 corresponding to the working furnace to deliver the gas to the pressure-stabilizing tank 22 corresponding to the working furnace;

[0076] When the pressure in the pressure-stabilizing tank 22 reaches a preset pressure value, the working furnace is operated; operating the working furnace includes:

[0077] Open the corresponding gas inlet valve 23 to deliver the gas to the working furnace, and open the corresponding cold air valve 31 to introduce the combustion-supporting gas into the working furnace to adjust the dome temperature of the working furnace until the working furnace is in a stable combustion stage;

[0078] In the stable combustion stage, when the continuous working time of the working furnace in the stable combustion stage reaches the preset working time, the shut-off valve 21 of the working furnace is closed and the shut-off valve 21 of the dormant furnace is opened at the same time, and then the gas inlet valve 23 corresponding to the working furnace is gradually closed and the corresponding cold air valve 31 is gradually closed synchronously until the gas inlet valve 23 is completely closed and the working furnace is in the heat storage stage; cold air is introduced into the working furnace, and the working furnace forms hot air after heat exchange with the cold air, and the generated hot air is introduced into the blast furnace 8;

[0079] The working furnace is switched to the new dormant furnace, and when the pressure in the pressure regulating tank 22 corresponding to the dormant furnace reaches the preset pressure value, the steps of operating the working furnace are repeated for the dormant furnace to switch the old dormant furnace to the new working furnace. By repeating this, the alternating cycle operation of the two hot blast furnaces 1 can be realized.

[0080] The combustion control method is implemented using the above-mentioned top-fired hot blast furnace 1 system, and has the same advantages, which will not be described in detail here.

[0081] Furthermore, operating the working furnace also includes:

[0082] Real-time detection of the dome temperature in the working furnace, and comparison of the dome temperature in the working furnace with a preset dome temperature upper limit;

[0083] Before the working furnace enters the stable combustion stage, if the dome temperature in the working furnace is lower than the preset dome temperature upper limit and the difference between the two is greater than the preset difference, then according to the dome temperature in the working furnace, the gas flow at the gas inlet valve 23 and the preset optimal air-fuel ratio, the gas flow and the combustion-supporting gas flow into the working furnace are adjusted so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference;

[0084] After the working furnace enters the stable combustion stage, if the dome temperature in the working furnace exceeds the preset dome temperature upper limit, the gas flow into the working furnace is adjusted so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference.

[0085] It can be understood that under normal circumstances, by adjusting the flow of the gas inlet valve 23 and / or the cold air valve 31 to control the flow of the gas and the combustion-supporting gas, the absolute value of the difference between the dome temperature and the preset dome temperature upper limit value can be controlled within the preset difference. At this time, when the continuous working time of one of the hot blast furnaces 1 in the stable combustion stage reaches the preset working time, the furnace replacement operation will be performed. If the difference between the dome temperature and the preset dome temperature upper limit value exceeds the preset difference during the operation of the current working furnace, it indicates that the current working furnace is abnormal, and the furnace replacement operation is also required at this time, and then the abnormal heat exchange furnace is manually inspected and maintained.

[0086] Therefore, under an abnormal working condition, the steps of operating the working furnace also include:

[0087] In the stable combustion stage, when the dome temperature of the working furnace is higher than the preset dome temperature upper limit by a difference greater than the preset difference, the shut-off valve 21 of the working furnace is closed and the vent valve 51 of the working furnace and the shut-off valve 21 of the dormant furnace are opened at the same time, and then the gas inlet valve 23 corresponding to the working furnace is gradually closed and the corresponding cold air valve 31 is gradually closed synchronously until the gas inlet valve 23 is completely closed.

[0088] In this embodiment, the preset optimal air-fuel ratio is preferably 0.6-0.8, and more preferably 0.7-0.75; the preset upper limit value of the dome temperature is preferably 1300-1500°C, and more preferably 1400-1450°C.

[0089] It can be understood that the working process of the hot blast furnace 1 includes a combustion period and a heat storage period (also referred to as a heat storage management period). After the furnace starts to burn, the hot blast furnace 1 is in the combustion period, and the dome temperature of the hot blast furnace 1 begins to gradually increase. After it increases to the preset dome temperature upper limit, it will burn stably for a period of time, so that the heat stored in the heat storage bricks set on the inner wall of the hot blast furnace 1 can meet the demand for hot gas delivery to the blast furnace 8, and then enter the heat storage period. The combustion period can be divided into the initial combustion period, the middle combustion period and the final combustion period according to the combustion time. In this embodiment, the period from the start of the furnace burning to the dome temperature of the hot blast furnace 1 rising to the difference between the preset dome temperature upper limit and the preset difference is called the initial furnace burning period, the period after the dome temperature rises to the difference between the preset dome temperature upper limit and the preset difference and burns stably for a period of time is called the middle furnace burning period (also referred to as the stable combustion period), and the period when the cut-off valve 21 corresponding to the hot blast furnace 1 is closed and the gas inlet valve 23 is gradually closed until the gas inlet valve 23 is completely closed is called the final furnace burning period. The burner is in the combustion stage during the entire combustion period, and stops working during the heat storage period. After the gas inlet valve 23 is completely closed, the hot blast furnace 1 is in the heat storage period, and can heat the incoming cold air (i.e., combustion-supporting gas) to form hot air to be sent to the blast furnace 8.

[0090] In order to better understand the combustion control method of the present embodiment, the two hot blast furnaces 1 are respectively recorded as the first hot blast furnace and the second hot blast furnace below, and the valves, the pressure-stabilizing tank 22 and the pipeline corresponding to the first hot blast furnace are respectively recorded as the first gas branch pipe, the first shut-off valve, the first pressure-stabilizing tank, the first gas flowmeter, the first combustion-supporting gas branch pipe, the first cold air valve, the first combustion-supporting gas flowmeter, the first hot blast branch pipe, the first hot air flowmeter, the first hot blast valve, the first exhaust gas branch pipe, and the first relief valve, and the valves, the pressure-stabilizing tank 22 and the pipeline corresponding to the second hot blast furnace are respectively recorded as the second gas branch pipe, the second shut-off valve, the second pressure-stabilizing tank, the second gas flowmeter, the second combustion-supporting gas branch pipe, the second cold air valve, the second combustion-supporting gas flowmeter, the second hot blast branch pipe, the second hot air flowmeter, the second hot blast valve, the second exhaust gas branch pipe, and the second relief valve. The above-mentioned combustion control process is described in more detail, as follows:

[0091] (1) First, the first hot blast furnace is used as a working furnace, and the second hot blast furnace is used as a dormant furnace.

[0092] (2) First, open the first shut-off valve to allow the gas to flow from the gas tank 6 along the gas main pipe 61 and the first gas branch pipe into the first pressure-stabilizing tank. The pressure change of the gas in the first pressure-stabilizing tank can be determined based on the pressure monitoring device (e.g., pressure gauge) on the first pressure-stabilizing tank.

[0093] (3) When the pressure in the first pressure-stabilizing tank reaches the preset pressure value, the first hot blast furnace is started to operate: the first gas inlet valve 23 is gradually opened to allow the gas to be stably and smoothly fed into the first hot blast furnace (after the first gas inlet valve 23 is opened, the first hot blast furnace begins to enter the furnace burning process, that is, enters the initial stage of the furnace burning period), the gas inlet flow of the first hot blast furnace is monitored, the first cold air valve is gradually opened according to the preset optimal air-fuel ratio, and air is gradually introduced synchronously to adjust the dome temperature of the first hot blast furnace, during which the dome temperature of the first hot blast furnace is detected (that is, the dome temperature is detected after the first gas inlet valve 23 is opened), and the dome temperature of the first hot blast furnace is compared with the preset dome temperature upper limit value:

[0094] Before the first hot blast furnace enters the stable heat storage stage, if the dome temperature of the first hot blast furnace is less than the preset dome temperature upper limit value and the difference between the two (the value of the preset dome temperature upper limit value minus the dome temperature of the first hot blast furnace) is greater than the preset difference value, then according to the obtained dome temperature of the first hot blast furnace, the gas flow entering the first hot blast furnace detected by the first gas flowmeter and the preset optimal air-fuel ratio, the opening of the first gas inlet valve 23 and the first cold air valve are adjusted to adjust the gas flow and the air flow, so that the absolute value of the difference between the dome temperature in the first hot blast furnace and the preset dome temperature upper limit value is within the preset difference value (taking the preset dome temperature upper limit value as 1450° and the preset difference as 10° as an example, the dome temperature of the working furnace should be adjusted to 1440-1460° at this time).

[0095] When the dome temperature of the working furnace (i.e. the first hot blast furnace) gradually rises to a preset difference with the preset upper limit of the dome temperature (at this time the dome temperature is still lower than the preset upper limit temperature but the difference between the two is equal to the preset difference, i.e. at this time the dome temperature of the first hot blast furnace reaches 1440°), the first hot blast furnace begins to be in a stable combustion stage, i.e. entering the middle stage of furnace firing, and the first hot blast furnace begins to store heat to store heat in the heat storage bricks.

[0096] After the first hot blast furnace enters the stable combustion stage, if the dome temperature of the first hot blast furnace exceeds the preset dome temperature upper limit value (for example, the dome temperature of the working furnace exceeds 1450°), the opening of the first gas inlet valve 23 is adjusted to adjust the gas flow rate entering the first hot blast furnace (for example, the gas flow rate entering the working furnace can be adjusted and determined according to the gas delivery model) so that the absolute value of the difference between the dome temperature of the first hot blast furnace and the preset dome temperature upper limit value is controlled within the preset difference (for example, controlled within 10°C, that is, the dome temperature of the first hot blast furnace is adjusted to 1440-1460°).

[0097] When the continuous working time of the first working furnace in the stable combustion stage reaches the preset working time, the furnace exchange operation between the two hot blast furnaces 1 is started, and the dome temperature and combustion time of the first hot blast furnace are continuously monitored during this furnace exchange period. The specific operation of the furnace exchange period includes the following three steps:

[0098] The first step: first close the first shut-off valve; while closing the first shut-off valve, open the second shut-off valve of the second hot blast stove, and at this time, the gas supplied to the first hot blast stove at the previous moment enters the second pressure-stabilizing tank of the second hot blast stove; the second gas inlet valve 23 is still kept closed, and at this time, no gas enters the second hot blast stove; the first hot blast stove is the hot blast stove 1 at the end of the burning, and the second hot blast stove is the hot blast stove 1 that will start burning at the next moment.

[0099] In the second step, according to the gas flow determined by the first gas flowmeter, the first gas inlet valve 23 of the first hot blast furnace is gradually closed and the first cold air valve is gradually closed synchronously, and the first hot blast furnace gradually stops burning until the first gas inlet valve 23 is completely closed. The stage from the closing of the first shut-off valve to the complete closing of the first gas inlet valve 23 is the end of the burning of the first hot blast furnace. At the end of the burning of the working furnace, the burning of the working furnace is gradually stopped in this embodiment. The shut-off valve 21 is closed first, and no gas enters the pressure regulating tank 22 at this time. Then the gas inlet valve 23 is gradually closed, and the cold air valve 31 is gradually closed synchronously to stop the burning of the hot blast furnace 1, which can avoid the sudden cut-off of the gas consumption of the gas system of the hot blast furnace 1, causing unnecessary damage to the hot blast furnace 1. After the first gas inlet valve is completely closed, the first hot blast furnace enters the heat storage stage (i.e., the heat storage period).

[0100] The third step is to open the flow of the first cold air valve to the maximum during the heat storage stage, and open the first hot air valve. The first hot air furnace exchanges heat with the cold air introduced to form hot air. The hot air generated by the first hot air furnace is introduced into the blast furnace 8 through the first hot air branch pipe and the hot air main pipe 81. After the hot air is introduced into the blast furnace 8 for a certain period of time, the first hot air valve and the first cold air valve are closed.

[0101] (4) After closing the first hot air valve and the first cold air valve of the first hot air furnace, the first hot air furnace is switched to a dormant furnace. After the first hot air valve and the first cold air valve are both closed and the pressure in the second pressure stabilizing tank reaches the preset pressure value, the second hot air furnace is operated as a working furnace, the second gas inlet valve of the second hot air furnace is gradually opened, and the second cold air valve is gradually opened, and the second hot air furnace starts to burn. At this time, the second gas inlet valve and the second shut-off valve of the second hot air furnace are both in an open state, and the pressure of the second pressure stabilizing tank is continuously monitored to ensure that the pressure in the second pressure stabilizing tank is stable in the working pressure range.

[0102] When the continuous working time of the second hot blast stove in the stable combustion stage reaches the preset working time, the three steps of the above-mentioned furnace change period are circulated, and when the second hot blast stove is switched to the dormant stove and the pressure in the first pressure stabilizing tank of the first hot blast stove reaches the preset pressure value, the step of operating the working stove is repeated for the first hot blast stove, and the first hot blast stove is switched to the working stove again. Such repetition can ensure that the two hot blast stoves 1 can complete the furnace change stably and smoothly during combustion.

[0103] As a special case, during the operation of the first hot blast furnace, when the difference between the vault temperature of the first hot blast furnace and the preset vault temperature upper limit value is greater than the preset difference (that is, the vault temperature of the first hot blast furnace exceeds 1460° at this time), it indicates that the first hot blast furnace is abnormal. At this time, it is necessary to switch the two hot blast furnaces 1, close the first shut-off valve of the first hot blast furnace and open the first relief valve and the second shut-off valve of the second hot blast furnace at the same time, so as to quickly reduce the pressure in the first hot blast furnace; then gradually close the first gas inlet valve and gradually close the first cold air valve at the same time to gradually cut off the gas of the first hot blast furnace, and the subsequent gas coal can ensure the safe pressure reduction and temperature reduction of the first hot blast furnace until the first gas inlet valve is completely closed; after closing the first relief valve, the first hot blast furnace is switched to a dormant furnace, and the operator can inspect and repair the first hot blast furnace. When the pressure in the second pressure-stabilizing tank of the second hot blast furnace reaches the preset pressure value, the second hot blast furnace is operated as a working furnace.

[0104] Furthermore, the above-mentioned gas transportation model can be implemented as follows:

[0105] One of the hot blast furnaces 1 is fired, the shut-off valve 21 is opened to pass the coal gas into the pressure regulating tank 22, after the pressure is stabilized, the coal gas inlet valve 23 is opened to gradually pass the coal gas into the hot blast furnace 1, and the coal gas is gradually passed into the hot blast furnace 1 at the same time. When the hot blast furnace 1 is in the firing process, the dome temperature of the hot blast furnace 1 is collected with a cycle of 10s. When the temperature reaches the preset dome temperature upper limit of -10℃, the gas flow C at this time is recorded. m1 , the burning time at this time is t 1 As the hot blast stove 1 continues to burn, when the dome temperature reaches the preset dome temperature upper limit, record the gas flow C at this time. m2 , the burning time at this time is t 2 When the dome temperature reaches the preset dome temperature upper limit + 10°C, record the gas flow C at this time m3 , the burning time at this time is t 3 ,A linear model between the gas flow rate and the dome temperature during stable combustion of the hot blast stove 1 is established based on the three sets of data, which can help to better adjust the combustion behavior of the hot blast stove 1.

[0106] In summary, the system and method of this embodiment have the following advantages:

[0107] (1) Two hot blast furnaces 1 are provided. The flow rates of the blast furnace 8 gas and air are controlled to match the fluctuating blast furnace 8 gas, so as to control the air-fuel ratio in the hot blast furnace 1, thereby improving the combustion thermal efficiency. By introducing the gas into the pressure stabilizing tank 22 in advance, the safety problem caused by the negative pressure inside the hot blast furnace 1 is ensured when the furnace is started and when the furnace is changed. The air and the gas are fully mixed through the matching hot blast furnace 1, and the combustion time of the mixed gas is appropriately extended, so that the mixed gas can be fully burned, thereby reducing the generation of nitrogen oxides and further improving the combustion thermal efficiency.

[0108] (2) Relying on monitoring equipment installed in various places, the status of the hot blast furnace 1 is monitored at any time and adjusted in time; before the coal gas enters the hot blast furnace 1, it first enters the pressure regulating tank 22 to ensure that the pressure of the hot blast furnace 1 can be kept stable when starting, stopping and changing the furnace; when the hot blast furnace 1 needs to be stopped urgently, the system pressure is quickly reduced through the relief valve 51 to ensure the safety of personnel; the control system has a hot blast furnace 1 matched with it, and in the combustion gas ring structure 14 and the coal gas ring structure 13 in the hot blast furnace 1, a group of coal gas diversion channels 135 are provided between each two groups of coal gas injection components, and a group of coal gas diversion channels 145 are provided between each two groups of combustion gas injection components. After the coal gas and air enter the combustion cavity 12, a swirling airflow can be generated, which accelerates the mixing of the coal gas and air and improves the swirl combustion efficiency.

[0109] (3) The entire combustion control method can match the combustion process of the hot blast furnace 1, and can transform the instantaneous gas cut-off or the cliff-like rigid change process of gas supply caused by the hot blast furnace 1 changing the furnace into a flexible gradual process, thereby improving the combustion efficiency, reducing the loss of the hot blast furnace 1, and making the furnace changing pressure more uniform. In addition, according to the heat and temperature control targets, the ratio of gas and air flow is adjusted to ensure the preset optimal air-fuel ratio. At the same time, the temperature of the dome of the hot blast furnace 1 is monitored, and the gas flow and / or air flow are continuously adjusted to adjust the dome temperature, so that the dome temperature of the hot blast furnace 1 is more uniform and the combustion is more complete when the hot blast furnace 1 is in the stable combustion stage. At the same time, the use of automatic control by the control device can reduce the labor intensity of the operator.

[0110] The above are only exemplary embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A top-fired hot blast stove system, characterized in that: Includes two hot air furnaces; Each of the hot blast furnaces is connected with a gas branch pipe, a combustion-supporting gas branch pipe, a hot blast branch pipe and a waste gas branch pipe. The gas branch pipe is used to introduce gas into the hot blast furnace, and a cut-off valve, a pressure-stabilizing tank and a gas inlet valve are sequentially arranged on the gas branch pipe along the gas delivery direction; the combustion-supporting gas branch pipe is used to introduce combustion-supporting gas into the hot blast furnace, and a cold air valve is arranged on the combustion-supporting gas branch pipe; the hot blast branch pipe is used to introduce the generated hot gas into the blast furnace, and a hot blast valve is arranged on the hot blast branch pipe; the waste gas branch pipe is used to introduce the generated waste gas into the waste heat boiler, and a vent valve is arranged on the waste gas branch pipe; The two hot blast stoves can operate alternately and cyclically, and the continuous working time of each hot blast stove in the stable combustion stage is not greater than the preset working time; when switching from one of the hot blast stoves to the other, first close the shut-off valve corresponding to one of the hot blast stoves and open the shut-off valve corresponding to the other hot blast stove at the same time, then gradually close the gas inlet valve corresponding to one of the hot blast stoves and gradually close the corresponding cold air valve simultaneously.

2. The top-fired hot blast stove system according to claim 1, characterized in that: A gas flow meter is also provided on the gas branch pipe and near the hot blast stove, a combustion-supporting gas flow meter is also provided on the combustion-supporting gas branch pipe and near the hot blast stove, and a hot air flow meter is also provided on the hot blast branch pipe and near the hot blast stove; a temperature detector is provided on the hot blast stove for detecting the dome temperature of the hot blast stove.

3. The top-fired hot blast stove system according to claim 2, characterized in that: The top-burning hot blast furnace system also includes a control device, which is electrically connected to the shut-off valve, the gas inlet valve, the gas flow meter, the cold air valve, the combustion-supporting gas flow meter, the hot air valve, the hot air flow meter, the vent valve and the temperature detector.

4. The top-fired hot blast stove system according to claim 1, characterized in that: The pressure-stabilizing tank includes an external shell, a gas storage airbag and a pressure monitoring device. The gas storage airbag is arranged in the external shell, and the pressure monitoring device can monitor the pressure in the gas storage airbag; an air inlet interface and an air outlet interface are provided on the gas storage airbag, and the air inlet interface and the air outlet interface are used to be connected in series to the gas branch pipe.

5. The top-fired hot blast stove system according to claim 4, characterized in that: The pressure stabilizing tank further comprises a tightening mechanism, which can tighten the gas storage airbag to adjust the volume in the gas storage airbag connected to the gas branch pipe.

6. The top-fired hot blast stove system according to claim 1, characterized in that: The hot blast furnace includes a furnace body with a dome on the top, a combustion cavity is formed in the upper part of the furnace body, and a coal gas ring channel structure and a combustion-supporting gas ring channel structure are arranged in the upper side wall of the furnace body at intervals. The coal gas ring channel structure can make the coal gas form a coal gas swirling airflow downward in the combustion cavity, and the combustion-supporting gas ring channel structure can make the combustion-supporting gas form a combustion-supporting gas swirling airflow upward in the combustion cavity, and the swirling flow directions of the coal gas swirling airflow and the combustion-supporting gas swirling airflow are opposite.

7. The top-fired hot blast stove system according to claim 6, characterized in that: The gas annular channel structure comprises a gas inlet channel, a gas annular channel, and a plurality of groups of gas diversion channels and a plurality of groups of gas injection structures arranged alternately in a circumferential order. The gas inlet channel is tangent to the gas annular channel and is used to connect the corresponding gas branch pipes. Each group of the gas injection structures comprises at least two groups of gas injection components arranged at intervals in the circumferential direction. Each group of the gas injection components comprises an upper gas channel and a lower gas channel arranged at intervals in the upper and lower directions. The upper gas channel comprises a first upper horizontal gas channel and an upper inclined gas channel connected in sequence from the outside to the inside. The outer end of the first upper horizontal gas channel is connected to the gas annular channel, and the inner end of the upper inclined gas channel is connected to the combustion cavity. The upper inclined gas channel is arranged obliquely downward from the first upper horizontal gas channel to the combustion cavity. The lower gas channel includes a first lower horizontal gas channel and a lower inclined gas channel connected in sequence from the outside to the inside, the outer end of the first lower horizontal gas channel is connected to the gas ring channel, the inner end of the lower inclined gas channel is connected to the combustion cavity, and the lower inclined gas channel is arranged obliquely upward from the first lower horizontal gas channel to the combustion cavity; the axes of the first upper horizontal gas channel and the first lower horizontal gas channel extend along the corresponding radial direction in the gas ring channel; each group of the gas diversion channels includes a second upper horizontal gas channel, a middle inclined gas channel and a second lower horizontal gas channel connected in sequence from the outside to the inside, the axis of the second upper horizontal gas channel is parallel to the axis of the second lower horizontal gas channel, and the axis of the second upper horizontal gas channel is inclined relative to the corresponding radial direction in the gas ring channel toward the annular airflow direction of the gas ring channel, and the axis of the middle inclined gas channel is inclined downward from the outer wall of the furnace body to the combustion cavity.

8. The top-fired hot blast stove system according to claim 6, characterized in that: The combustion-supporting gas annular channel structure comprises a combustion-supporting gas inlet channel, a combustion-supporting gas annular channel, and a plurality of combustion-supporting gas diversion channels and a plurality of combustion-supporting gas jet structures which are alternately arranged in a circumferential order, the combustion-supporting gas inlet channel is tangent to the combustion-supporting gas annular channel and is used to connect the corresponding combustion-supporting gas branch pipe; each group of the combustion-supporting gas jet structures comprises at least two groups of combustion-supporting gas jet assemblies which are arranged at intervals in a circumferential order, each group of the combustion-supporting gas jet assemblies comprises an upper combustion-supporting gas channel and a lower combustion-supporting gas channel which are arranged at intervals in the upper and lower directions, the upper combustion-supporting gas channel comprises a first upper horizontal combustion-supporting gas channel and an upper inclined combustion-supporting gas channel which are sequentially connected from the outside to the inside, and the outer end portion of the first upper horizontal combustion-supporting gas channel is in communication with the combustion-supporting gas annular channel, the inner end portion of the upper inclined combustion-supporting gas channel is in communication with the combustion inner cavity, and the upper inclined combustion-supporting gas channel is arranged obliquely downward from the first upper horizontal combustion-supporting gas channel toward the combustion inner cavity; The lower combustion gas channel comprises a first lower horizontal combustion gas channel and a lower inclined combustion gas channel connected in sequence from outside to inside, the outer end of the first lower horizontal combustion gas channel is connected to the combustion gas ring channel, the inner end of the lower inclined combustion gas channel is connected to the combustion inner cavity, and the lower inclined combustion gas channel is arranged obliquely upward from the first lower horizontal combustion gas channel to the combustion inner cavity; the axes of the first upper horizontal combustion gas channel and the first lower horizontal combustion gas channel both extend along the corresponding radial direction in the combustion gas ring channel; each group of the combustion gas diversion channels comprises a second lower horizontal combustion gas channel, a middle inclined combustion gas channel and a second upper horizontal combustion gas channel connected in sequence from outside to inside, the axis of the second lower horizontal combustion gas channel is parallel to the axis of the second upper horizontal combustion gas channel, and the axis of the second lower horizontal combustion gas channel is inclined relative to the corresponding radial direction in the combustion gas ring channel toward the annular airflow direction of the combustion gas ring channel, and the axis of the middle inclined combustion gas channel is inclined upward from the outer wall of the furnace body to the combustion inner cavity.

9. A combustion control method for a top-fired hot blast stove system according to any one of claims 1 to 8, characterized in that: include: One of the hot blast furnaces is used as a working furnace, and the other hot blast furnace is used as a dormant furnace; Open the shut-off valve corresponding to the working furnace to deliver the gas to the pressure-stabilizing tank corresponding to the working furnace; When the pressure in the pressure-stabilizing tank reaches a preset pressure value, the working furnace is operated; Running a working furnace includes: Open the corresponding gas inlet valve to deliver the gas into the working furnace, open the corresponding cold air valve to introduce the combustion-supporting gas into the working furnace, so as to adjust the dome temperature of the working furnace until the working furnace is in a stable combustion stage; In the stable combustion stage, when the continuous working time of the working furnace in the stable combustion stage reaches the preset working time, the shut-off valve of the working furnace is closed and the shut-off valve of the dormant furnace is opened at the same time, and then the gas inlet valve corresponding to the working furnace is gradually closed and the corresponding cold air valve is gradually closed synchronously until the gas inlet valve is completely closed, and the working furnace is in the heat storage stage; cold air is introduced into the working furnace, and the working furnace forms hot air after heat exchange with the cold air, and the generated hot air is introduced into the blast furnace; The working furnace is switched to a new dormant furnace. When the pressure in the pressure-stabilizing tank corresponding to the dormant furnace reaches a preset pressure value, the steps of operating the working furnace are repeated for the dormant furnace to switch the old dormant furnace to the new working furnace.

10. The combustion control method of a top-fired hot blast stove system according to claim 9, characterized in that: Running a working furnace also includes: Real-time detection of the dome temperature in the working furnace, and comparison of the dome temperature in the working furnace with a preset dome temperature upper limit; Before the working furnace enters the stable combustion stage, if the dome temperature in the working furnace is lower than the preset dome temperature upper limit and the difference between the two is greater than the preset difference, then according to the dome temperature in the working furnace, the gas flow at the gas inlet valve and the preset optimal air-fuel ratio, the gas flow and the combustion-supporting gas flow into the working furnace are adjusted so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit is within the preset difference; After the working furnace enters the stable combustion stage, if the dome temperature in the working furnace exceeds the preset dome temperature upper limit value, the gas flow rate entering the working furnace is adjusted so that the absolute value of the difference between the dome temperature in the working furnace and the preset dome temperature upper limit value is within the preset difference.

11. The combustion control method of a top-fired hot blast stove system according to claim 10, characterized in that: The step of operating the working furnace also includes: In the stable combustion stage, when the dome temperature of the working furnace is higher than the preset dome temperature upper limit by a difference greater than the preset difference, the shut-off valve of the working furnace is closed and the vent valve of the working furnace and the shut-off valve of the dormant furnace are opened at the same time, and then the gas inlet valve corresponding to the working furnace is gradually closed and the corresponding cold air valve is gradually closed synchronously until the gas inlet valve is completely closed.

12. The combustion control method of a top-fired hot blast stove system according to claim 10, characterized in that: The preset optimal air-fuel ratio is 0.6-0.8, and the preset upper limit value of the dome temperature is 1300-1500°C.

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