Dry quenching waste heat recovery method and device for primary converter flue gas

Abstract

The present invention relates to the technical field of waste heat recovery facilities for steelmaking converters in iron and steel enterprises, and particularly relates to a method and device for dry quenching waste heat recovery of primary converter flue gas, including a radiant waste heat boiler, a convective waste heat boiler, an inertial dust removal device, and a dry quenching chamber for extinguishing open flames in the flue gas and reducing the energy of spark particulate matter in the flue gas; a vaporization cooling flue, the radiant waste heat boiler, the dry quenching chamber, the inertial dust removal device, and the convective waste heat boiler are sequentially connected along the flue gas flow direction, and a quenching gas inlet is arranged on the dry quenching chamber, and the quenching gas inlet is connected to a quenching gas source. The present invention fully recovers the waste heat of the primary converter flue gas at 900°C to 250°C, can achieve full dry waste heat recovery and purification, and avoids the risk of flash explosion of converter gas in the range of 605 to 650°C, significantly improving the safety of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery facilities for steelmaking converters in iron and steel enterprises, and particularly relates to a method and device for dry quenching waste heat recovery of primary converter gas. Background Art

[0002] During converter smelting, the temperature of the primary gas at the outlet of the vaporization flue of a conventional converter design is 900°C to 1000°C, and then it enters a wet dust removal or dry dust removal system. Usually, the temperature is reduced to about 200°C by spraying water for cooling before purification and recovery treatment. During this process, the waste heat of the gas from 900°C to 200°C is not recovered and utilized, all of which belongs to wasted waste heat. The main reason for not recovering this part of the waste heat is the risk of explosion of converter gas in the medium and low temperature range. According to the thermodynamics of combustible gases, the explosion of gas must simultaneously meet the following three conditions:

[0003] 1) The mixing ratio of carbon monoxide with oxygen or air is within the explosion limit range;

[0004] 2) Carbon monoxide is premixed with oxygen or air below the auto-ignition point (605 - 650°C);

[0005] 3) Encounter an open flame or a spark with sufficient energy.

[0006] Therefore, in order to ensure the recovery and utilization of this part of the heat under the premise of safety, it is necessary to ensure that the above three conditions cannot be met simultaneously. Summary of the Invention

[0007] The purpose of the present invention is to provide a method and device for dry quenching waste heat recovery of primary converter gas, which can fully recover the waste heat of the primary converter gas from 900°C to 250°C under the premise of ensuring safety, eliminate the water spraying in the gas purification process, and achieve high safety, full dry purification and waste heat recovery.

[0008] To achieve the above purpose, the technical solution of the present invention is a dry quenching waste heat recovery device for primary converter gas, including a radiant waste heat boiler, a convective waste heat boiler, an inertial dust removal device, and a dry quenching chamber for extinguishing the open flame in the gas and reducing the energy of the spark particulate matter in the gas; the vaporization cooling flue, the radiant waste heat boiler, the dry quenching chamber, the inertial dust removal device, and the convective waste heat boiler are sequentially connected along the gas flow direction, and the dry quenching chamber is provided with a quenching gas inlet, and the quenching gas inlet is connected to a quenching gas source.

[0009] As one of the implementation modes, the dry quenching chamber includes an air inlet section and a mixed air cooling section arranged in sequence from top to bottom. The top of the air inlet section is connected to the radiant waste heat boiler, the bottom of the mixed air cooling section is connected to the inertial dust removal device, and the quenching gas inlet is arranged on the air inlet section.

[0010] As one of the embodiments, the air inlet section is a double-layer structure composed of an inner wall and an outer wall. The quench gas inlet is provided on the outer wall, the air supply opening is provided on the inner wall, and the bottom of the inner wall is communicated with the top of the mixed air cooling section.

[0011] As one of the embodiments, a pressure relief valve is installed on the side wall of the mixed air cooling section.

[0012] As one of the embodiments, the dry quench chamber introduces the flue gas at the outlet of the convective waste heat boiler into the dry quench chamber through a quench gas bypass pipe as a quench gas source, and a gas axial flow fan is provided in the quench gas bypass pipe.

[0013] As one of the embodiments, a gas check device is further provided in the quench gas bypass pipe, and the gas check device is located between the quench gas inlet and the gas axial flow fan.

[0014] As one of the embodiments, the radiative waste heat boiler is connected to the dry quench chamber through a compensator.

[0015] The present invention also provides a method for dry quenching and waste heat recovery of converter primary flue gas. Using the converter primary flue gas dry quenching and waste heat recovery device described in any one of the above, the method includes the following steps:

[0016] 1) During converter smelting, the flue gas with a temperature of 900 - 1000 °C at the outlet of the vaporization cooling flue enters the radiative waste heat boiler for waste heat recovery, and the temperature of the flue gas drops to 660 - 700 °C after radiative heat exchange;

[0017] 2) The flue gas with a temperature of 660 - 700 °C at the outlet of the radiative waste heat boiler enters the dry quench chamber and is mixed and quenched with the quench gas. The temperature of the flue gas is quenched to 500 °C - 550 °C, extinguishing the open fire in the flue gas and reducing the energy of the spark particulate matter in the flue gas;

[0018] 3) The flue gas with a temperature of 500 °C - 550 °C at the outlet of the dry quench chamber first enters the inertial dust removal device to remove coarse dust, and then enters the convective waste heat boiler for waste heat recovery. The temperature of the flue gas drops to 250 °C after convective heat exchange;

[0019] 4) The flue gas with a temperature of 250 °C at the outlet of the convective waste heat boiler is transported to the subsequent device through a gas pipeline for gas purification and recovery.

[0020] As one of the embodiments, in step 2), a part of the flue gas at the outlet of the convective waste heat boiler is introduced into the dry quench chamber through the quench gas bypass pipe as the quench gas.

[0021] As one of the implementation manners, a gas axial-flow fan is adopted in the quench gas bypass pipe as the power for bypassing the quench gas, and the gas axial-flow fan adjusts the flow rate of the quench gas by adopting a variable frequency speed regulation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) During the converter smelting, the present invention fully recovers the waste heat of 900°C - 250°C of the converter primary flue gas, can achieve high-safety and fully dry waste heat recovery, and effectively reduces the production cost of steel products;

[0024] (2) The present invention effectively extinguishes the open fire and reduces the energy of the spark particulate matters through the dry quench chamber, avoids the risk of flash explosion of the converter gas in the range of 605 - 650°C, realizes the safe recovery of the converter gas waste heat, and the dry quench chamber is provided with a rupture disc to further ensure the safety of the equipment;

[0025] (3) The quench gas adopted by the present invention is directly introduced from the flue gas at the outlet of the convective waste heat boiler nearby, with less energy consumption;

[0026] (4) The present invention adopts a gas axial-flow fan as the bypass power for the quench gas and adopts variable frequency speed regulation to adjust the flow rate of the quench gas;

[0027] (5) The present invention removes a part of the soot through the inertial dust removal device, reducing the scaling and erosion of the convective waste heat boiler;

[0028] (6) The present invention is provided with a gas check valve on the quench gas bypass pipe, which can prevent the reverse flow of the gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a schematic diagram of the converter primary flue gas dry quench waste heat recovery device provided by the embodiment of the present invention;

[0031] Figure 2 It is a schematic structural diagram of the dry quench chamber provided by the embodiment of the present invention;

[0032] Figure 3 It is for Figure 2 the A-A cross-sectional view of

[0033] In the figure: 1. Vaporization cooling flue; 2. Radiation waste heat boiler; 3. Compensator; 4. Dry quench chamber; 4-1. Air inlet section; 4-1a. Outer wall; 4-1b. Inner wall; 4-1c. Air supply opening; 4-2. Mixed air cooling section; 4-3. Explosion relief valve; 5. Inertial dust removal device; 6. Convection waste heat boiler; 7. Gas axial flow fan; 8. Quench gas bypass pipe; 9. Gas check device; 10. Gas pipeline. Detailed implementation manners

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0036] Embodiment 1

[0037] As Figure 1 shown, this embodiment provides a dry quench waste heat recovery device for converter primary flue gas, including a radiation waste heat boiler 2, a convection waste heat boiler 6, an inertial dust removal device 5, and a dry quench chamber 4 for extinguishing the open fire in the flue gas and reducing the energy of the fire particles in the flue gas; a vaporization cooling flue 1, the radiation waste heat boiler 2, the dry quench chamber 4, the inertial dust removal device 5, and the convection waste heat boiler 6 are connected in sequence along the flue gas flow direction, and a quench gas inlet is provided on the dry quench chamber 4, and the quench gas inlet is connected to a quench gas source.

[0038] In this embodiment, a quench gas is introduced into the dry quench chamber 4 to quench and cool the flue gas at the outlet of the radiant waste heat boiler 2, extinguish the flue gas in the flue gas, and reduce the energy of the spark particulate matter in the flue gas, avoiding the risk of flash explosion of converter gas in the range of 605 - 650 °C, effectively improving the safety of converter gas waste heat recovery. At the same time, the radiant waste heat boiler 2 and the convective waste heat boiler 6 fully recover the waste heat of the converter primary flue gas from 900 °C to 250 °C, realizing high-safety, fully dry waste heat recovery and purification, reducing the production cost of steel products; and before the convective waste heat boiler 6, a inertial dust removal device 5 is used to remove the coarse dust in the flue gas, reducing the scaling and erosion of the convective waste heat boiler 6.

[0039] Refining the above embodiment, as Figure 2 and Figure 3 shown, the dry quench chamber 4 includes an air inlet section 4-1 and a mixed air cooling section 4-2 arranged in sequence from top to bottom. The top of the air inlet section 4-1 is connected to the radiant waste heat boiler 2, the bottom of the mixed air cooling section 4-2 is connected to the inertial dust removal device 5, and the quench gas inlet is arranged on the air inlet section 4-1. Further, the air inlet section 4-1 is a double-layer structure composed of an inner wall 4-1b and an outer wall 4-1a. The quench gas inlet is arranged on the outer wall 4-1a, and an air supply port 4-1c is arranged on the inner wall 4-1b. The bottom of the inner wall 4-1b is communicated with the top of the mixed air cooling section 4-2. Among them, the cavity surrounded by the inner wall 4-1b is communicated with the cavity of the mixed air cooling section 4-2. The outer wall 4-1a is sleeved outside the inner wall 4-1b and is sealed at the upper and lower ends. The space between the inner wall 4-1b and the outer wall 4-1a serves as an air supply channel. The quench gas enters the quench gas inlet through the quench gas inlet, and then enters the cavity of the inner wall 4-1b through the air supply port 4-1c and is mixed and quenched with the high-temperature flue gas from the radiant waste heat boiler 2 in the mixed air cooling section 4-2, extinguishing the open fire in the flue gas and reducing the energy of the spark particulate matter in the flue gas, avoiding the risk of flash explosion of converter gas in the range of 605 - 650 °C.

[0040] Further, there are several air supply ports 4-1c, and several air supply ports 4-1c are arranged at equal intervals along the circumferential direction of the inner wall 4-1b, so that the quench gas can be quickly and evenly mixed with the high-temperature flue gas from the radiant waste heat boiler 2, the temperature can be evenly reduced, and the occurrence of open fire and the escape of sparks can be avoided.

[0041] Optimally, as Figure 2 shown, a rupture disc 4-3 is installed on the side wall of the mixed air cooling section 4-2. Multiple rupture discs 4-3 can be set. When the pressure in the mixed air cooling section 4-2 exceeds the set value, the rupture disc 4-3 opens to relieve pressure, further ensuring the safety of the equipment.

[0042] Optimize the above embodiment. The dry quench chamber 4 introduces the flue gas at the outlet of the convective waste heat boiler 6 into the dry quench chamber 4 as a quench gas source through the quench gas bypass pipe 8, and a gas axial flow fan 7 is arranged in the quench gas bypass pipe 8. In this embodiment, the gas axial flow fan 7 is used as the power for the quench gas bypass, and the low-temperature flue gas at the outlet of the convective waste heat boiler 6 is introduced into the dry quench chamber 4 nearby as the quench gas to quench and cool the high-temperature flue gas at the outlet of the radiant waste heat boiler 2, which can reduce energy consumption. Among them, the gas axial flow fan 7 can adopt a variable frequency speed regulation motor, and the quench gas flow can be adjusted through variable frequency speed regulation, so as to control the flue gas temperature at the outlet of the dry quench chamber 4.

[0043] Further, a gas check device 9 is also arranged in the quench gas bypass pipe 8, and the gas check device 9 is located between the quench gas inlet and the gas axial flow fan 7. By adding the gas check device 9 in the cold gas bypass pipe, gas backflow can be prevented.

[0044] As one of the implementation manners, the radiant waste heat boiler 2 is connected to the dry quench chamber 4 through a compensator 3 to absorb the thermal displacement of the equipment and avoid damaging the equipment.

[0045] Embodiment 2

[0046] As Figures 1-3 shown, this embodiment provides a method for dry quenching and waste heat recovery of the primary converter gas, adopting the dry quenching and waste heat recovery device of the primary converter gas provided in Embodiment 1. This method includes the following steps:

[0047] 1) During converter smelting, the flue gas with a temperature of 900 - 1000 °C at the outlet of the vaporization cooling flue 1 enters the radiant waste heat boiler 2 for waste heat recovery, and the temperature of the flue gas drops to 660 - 700 °C after radiation heat exchange;

[0048] 2) The flue gas with a temperature of 660 - 700 °C at the outlet of the radiant waste heat boiler 2 enters the dry quench chamber 4 and is mixed and quenched with the quench gas, and the temperature of the flue gas is quenched to 500 °C - 550 °C. The dry quench chamber 4 effectively extinguishes the open fire in the flue gas and reduces the energy of the spark particulate matter in the flue gas, avoiding the risk of flash explosion of the converter gas in the range of 605 - 650 °C; at the same time, a rupture disc 4 - 3 is arranged in the dry quench chamber 4 to ensure the safety of the equipment;

[0049] 3) The flue gas with a temperature of 500 °C - 550 °C at the outlet of the dry quench chamber 4 first enters the inertial dust removal device 5 to remove the coarse dust, and then enters the convective waste heat boiler 6 for waste heat recovery, and the temperature of the flue gas drops to 250 °C after convective heat exchange;

[0050] 4) The flue gas with a temperature of 250 °C at the outlet of the convective waste heat boiler 6 is transported to the subsequent device through the gas pipeline 10 for gas purification and recovery.

[0051] Preferably, in step 2), a part of the flue gas (temperature ~ 250 °C) at the outlet of the convective waste heat boiler 6 is introduced into the dry quench chamber 4 through the quench gas bypass pipe 8 as the quench gas; in step 4), a part of the flue gas at 250 °C at the outlet of the convective waste heat boiler 6 enters the quench gas bypass pipe 8 and is introduced into the dry quench chamber 4 as the quench gas, and the other part is transported through the gas pipeline 10 to the subsequent device for gas purification and recovery. In this embodiment, the quench gas is directly taken from the flue gas at the outlet of the convective waste heat boiler 6, which can reduce energy consumption.

[0052] Furthermore, a gas axial flow fan 7 is arranged in the quench gas bypass pipe 8 as the power for the quench gas bypass. The gas axial flow fan 7 adjusts the flow rate of the quench gas by means of variable frequency speed regulation, so as to control the flue gas temperature at the outlet of the dry quench chamber 4. A gas check valve device 9 is also arranged in the quench gas bypass pipe 8 to prevent the reverse flow of gas.

[0053] The above embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention. For example, adjust the form of the gas axial flow fan 7, adopt a centrifugal fan, adjust the inlet and outlet flue gas temperatures of the radiant waste heat boiler 2, adjust the inlet and outlet flue gas temperatures of the convective waste heat boiler 6, adjust the position of the quench gas bypass pipe 8, adjust the number and arrangement position of the air supply openings 4-1c. These equivalent forms also fall within the scope defined by the appended claims of the present invention.

Claims

1. A dry quenching waste heat recovery device for the primary flue gas of a converter, characterized in that: It includes a radiation waste heat boiler, a convection waste heat boiler, an inertial dust removal device, and a dry quenching chamber for extinguishing the open fire in the flue gas and reducing the energy of the spark particulate matter in the flue gas; a vaporization cooling flue, the radiation waste heat boiler, the dry quenching chamber, the inertial dust removal device, and the convection waste heat boiler are connected in sequence along the flue gas flow direction. A quenching gas inlet is provided on the dry quenching chamber, and the quenching gas inlet is connected to a quenching gas source; the dry quenching chamber includes an air inlet section and a mixed air cooling section arranged successively from top to bottom. The top of the air inlet section is connected to the radiation waste heat boiler, the bottom of the mixed air cooling section is connected to the inertial dust removal device, and the quenching gas inlet is provided on the air inlet section; the air inlet section is a double-layer structure composed of an inner wall and an outer wall. The quenching gas inlet is provided on the outer wall, and an air supply port is provided on the inner wall. The bottom of the inner wall communicates with the top of the mixed air cooling section; there are several air supply ports, and several air supply ports are arranged at equal intervals along the circumferential direction of the inner wall; the dry quenching chamber introduces the flue gas at the outlet of the convection waste heat boiler into the dry quenching chamber through a quenching gas bypass pipe as a quenching gas source.

2. The dry quenching waste heat recovery device for the primary flue gas of a converter according to claim 1, characterized in that: A bursting disc is installed on the side wall of the mixed air cooling section.

3. The dry quenching waste heat recovery device for the primary flue gas of a converter according to claim 1, characterized in that: An axial flow gas blower for gas is provided in the quenching gas bypass pipe.

4. The dry quenching waste heat recovery device for the primary flue gas of a converter according to claim 3, characterized in that: A gas check device is further provided in the quenching gas bypass pipe, and the gas check device is located between the quenching gas inlet and the axial flow gas blower for gas.

5. The dry quenching waste heat recovery device for the primary flue gas of a converter according to claim 1, characterized in that: The radiation waste heat boiler is connected to the dry quenching chamber through a compensator.

6. A dry quenching waste heat recovery method for the primary flue gas of a converter, characterized in that, The dry quenching waste heat recovery device for the primary flue gas of a converter according to any one of claims 1-5 is adopted, and the method includes the following steps: 1) During converter smelting, the flue gas with a temperature of 900°C to 1000°C at the outlet of the vaporization cooling flue enters the radiation waste heat boiler for waste heat recovery, and the temperature of the flue gas drops to 660°C to 700°C after radiation heat exchange; 2) The flue gas with a temperature of 660°C to 700°C at the outlet of the radiation waste heat boiler enters the dry quenching chamber and is mixed and quenched with the quenching gas, and the temperature of the flue gas is quenched to 500°C to 550°C, extinguishing the open fire in the flue gas and reducing the energy of the spark particulate matter in the flue gas; 3) The flue gas with a temperature of 500°C to 550°C at the outlet of the dry quenching chamber first enters the inertial dust removal device to remove coarse dust, and then enters the convection waste heat boiler for waste heat recovery, and the temperature of the flue gas drops to 250°C after convection heat exchange. 4) The flue gas with a temperature of 250 °C at the outlet of the convective waste heat boiler is transported through a gas pipeline to subsequent devices for gas purification and recovery.

7. The dry quenching waste heat recovery method for the primary converter flue gas according to claim 6, characterized in that: In step 2), part of the flue gas at the outlet of the convective waste heat boiler is introduced into the dry quenching chamber through a quench gas bypass pipe as the quench gas.

8. The dry quenching waste heat recovery method for the primary converter flue gas according to claim 7, characterized in that: A gas axial flow fan is used as the power for the quench gas bypass in the quench gas bypass pipe, and the gas axial flow fan adjusts the flow rate of the quench gas by means of variable frequency speed regulation.

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