Wet chilling-based waste heat recovery system for primary flue gas of converter

Abstract

A wet chilling-based waste heat recovery system for primary flue gas of a converter. The system comprises a vaporization cooling flue (1), a first waste heat boiler (2), a wet-chilling fire extinguishing chamber (4) and a dust removal device (5) which are sequentially connected in a flue gas flowing direction. A multi-stage spraying mechanism used for spraying flue gas is provided upstream of the wet-chilling fire extinguishing chamber (4). According to the system, by providing the multi-stage spraying mechanism and the wet-chilling fire extinguishing chamber (4), on one hand, naked flames can be effectively extinguished, and energy of fire particles can be reduced, thereby avoiding the risk of flash explosion of converter gas at 605-650°C, and achieving safe recovery of waste heat of the converter gas; and on the other hand, spraying of atomized water can promote agglomeration of particles in the flue gas, and small particles are agglomerated into large particles, and can be removed better by the dust removal device (5), thereby improving the dust removal effect of the flue gas.

Description

Converter primary flue gas wet quenching waste heat recovery system Technical Field

[0001] The utility model relates to the technical field of flue gas waste heat recovery, in particular to a converter primary flue gas wet quenching waste heat recovery system. Background Art

[0002] During converter smelting, the primary flue gas temperature at the vaporization flue outlet of a conventional converter ranges from 900°C to 1000°C. It then enters a wet or dry dust removal system, where the temperature is reduced to approximately 200°C before purification and recovery. Consequently, the waste heat from the flue gas between 900°C and 200°C is wasted. The main reason this waste heat isn't recovered is the risk of explosion in the medium- and low-temperature ranges of converter gas.

[0003] Combustible gas thermodynamics shows that for a gas explosion to occur, the following three conditions must be met simultaneously: 1) the mixture ratio of carbon monoxide to oxygen or air is within the explosion limit; 2) carbon monoxide and oxygen or air are premixed below their autoignition point (605°C to 650°C); and 3) there is an open flame or a sufficiently energetic fire. To ensure the safe recovery of this heat, measures must be taken to eliminate at least one of these conditions. Furthermore, while maximizing the recovery of waste heat from the low and medium temperature stages, particulate matter in the flue gas must be removed and purified.

[0004] Utility Model Content

[0005] In order to solve the above problems, the utility model provides a converter primary flue gas wet quenching waste heat recovery system, including a vaporization cooling flue, a first waste heat boiler, a wet quenching fire extinguishing chamber and a dust removal device connected in sequence along the flue gas flow direction, and a multi-stage spraying mechanism for spraying the flue gas is provided upstream of the wet quenching fire extinguishing chamber.

[0006] Furthermore, the multi-stage spray mechanism includes a first-stage spray mechanism and a second-stage spray mechanism, the first-stage spray mechanism is arranged in the vaporization cooling flue, and the second-stage spray mechanism is arranged in the first waste heat boiler.

[0007] Furthermore, a chamber is provided in the wet quenching fire extinguishing chamber, and the smoke outlet of the wet quenching fire extinguishing chamber is conical and gradually shrinks along the direction of smoke flow.

[0008] Furthermore, a plurality of explosion relief valves are provided on the side walls of the wet quenching fire extinguishing chamber.

[0009] Furthermore, it also includes a second waste heat boiler, which is connected to the flue gas outlet of the dust removal device.

[0010] Furthermore, the flue gas outlet of the second waste heat boiler is connected to a gas pipeline.

[0011] Furthermore, the dust removal device is also connected to a high-temperature ash conveying device, and the outlet end of the high-temperature ash conveying device is connected to a waste heat recovery device.

[0012] Furthermore, the flue gas outlet of the first waste heat boiler is connected to the flue gas inlet of the wet quenching fire extinguishing chamber through a compensator.

[0013] Furthermore, the dust removal device includes at least one of an inertial dust removal device, a gravity dust removal device, a centrifugal dust removal device and a bag dust removal device.

[0014] Furthermore, the first waste heat boiler is a radiation waste heat boiler or a convection waste heat boiler, and / or the second waste heat boiler is a radiation waste heat boiler or a convection waste heat boiler.

[0015] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0016] 1) The waste heat recovery system provided by the present invention, by providing a multi-stage spray mechanism and a wet quenching fire extinguishing chamber, can, on the one hand, effectively extinguish open flames and reduce the energy of fire particles, thereby avoiding the risk of flash explosion of converter gas in the range of 605-650°C and achieving safe recovery of converter gas waste heat. On the other hand, the multi-stage spray mechanism sprays atomized water into the flue gas, which can promote the agglomeration of particles in the flue gas. Fine particles agglomerate into large particles, which are more conducive to removal in the dust removal device, thereby improving the dust removal effect of the flue gas.

[0017] 2) The waste heat recovery system provided by the present invention fully recovers the waste heat of 900°C to 200°C of the converter primary flue gas during converter smelting, achieving high safety and deep waste heat recovery and purification;

[0018] 3) The waste heat recovery system provided by the present invention is equipped with a waste heat recovery device at the outlet of the high-temperature ash conveying device, which can perform deep waste heat recovery on the high-temperature granular dust;

[0019] 4) The waste heat recovery system provided by the present invention is provided with a primary spray mechanism and a secondary spray mechanism, which ensures that the flue gas containing high-temperature large particles is quenched and extinguished when the temperature is above 650°C, thereby ensuring the safety of the waste heat recovery system;

[0020] 5) In the waste heat recovery system provided by the present invention, the atomized water sprayed by the first and second spray mechanisms is vaporized after heat exchange with the high-temperature flue gas, and part of the heat of the high-temperature steam is recovered in the second waste heat boiler;

[0021] 6) The waste heat recovery system provided by the present invention is equipped with a dust removal device at the flue gas outlet of the wet quenching fire extinguishing chamber, which can effectively remove particulate matter in the flue gas after spraying, purify the flue gas, avoid scaling and clogging of the second waste heat boiler, and ensure the stability of the waste heat recovery system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] FIG1 is a schematic structural diagram of a converter primary flue gas wet quenching waste heat recovery system provided by the present invention.

[0024] 1- Vaporization cooling flue; 2- First waste heat boiler; 3- Compensator; 4- Wet quenching fire extinguishing chamber; 5- Dust removal device; 6- Second waste heat boiler; 7- First-stage spray mechanism; 8- Second-stage spray mechanism; 9- High-temperature ash conveying device; 10- Waste heat recovery device; 11- Gas pipeline; 12- Explosion relief valve. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention. In the drawings, the size and relative sizes of some parts may be exaggerated for clarity.

[0026] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connection" and "connected" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the description of the present invention, the terms "up", "down", "left", "right", "front", "back", "center", "horizontal", "vertical", "top", "bottom", "inside", "outside" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0028] Furthermore, in the description of this utility model, the terms "first" and "second" are used solely to distinguish between the features in the description and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Furthermore, features designated as "first" or "second" may explicitly or implicitly include one or more of the features.

[0029] As shown in Figure 1 of the specification, the utility model provides a converter primary flue gas wet quenching waste heat recovery system, comprising a vaporization cooling flue 1, a first waste heat boiler 2, a wet quenching fire extinguishing chamber 4, a dust removal device 5 and a second waste heat boiler 6 connected in sequence along the flue gas flow direction, the flue gas inlet of the first waste heat boiler 2 is connected to the vaporization cooling flue 1, and a multi-stage spraying mechanism for spraying the flue gas is provided upstream of the wet quenching fire extinguishing chamber 4.

[0030] During converter smelting, the flue gas temperature at the flue gas outlet of the vaporization cooling flue 1 is 900-1000°C, and the flue gas enters the first waste heat boiler 2 for waste heat recovery. The outlet flue gas temperature of the first waste heat boiler 2 is 660-700°C, and the first waste heat boiler 2 can preliminarily recover part of the waste heat of the flue gas.

[0031] In this embodiment, a chamber is provided in the wet quenching fire extinguishing chamber 4 for fully mixing the flue gas and the atomized spray water and for heat exchange. The multi-stage spraying mechanism is provided upstream of the wet quenching fire extinguishing chamber 4. The multi-stage spraying mechanism sprays atomized water into the flue gas. The atomized water and the flue gas are mixed and enter the chamber of the wet quenching fire extinguishing chamber 4. The high-temperature flue gas can be wet-quenched by the atomized water sprayed by the multi-stage spraying mechanism. The flue gas temperature is quenched to a range of 550 to 600°C. The open flame is effectively extinguished in the wet quenching fire extinguishing chamber 4 and the energy of the fire particles is reduced, thereby avoiding the risk of flash explosion of the converter gas in the range of 605 to 650°C.

[0032] In an optimized implementation mode, the smoke outlet of the wet quenching fire extinguishing chamber 4 is conical and gradually shrinks along the smoke flow direction.

[0033] In an optimized implementation method, a plurality of explosion relief valves 12 are provided on the side walls of the wet chilled fire extinguishing chamber 4. When the pressure sensor detects that the pressure in the wet chilled fire extinguishing chamber 4 is too high, the explosion relief valve 12 can be opened to adjust the pressure of the wet chilled fire extinguishing chamber 4 to ensure the safety of the equipment.

[0034] In the optimized implementation mode, the multi-stage spray mechanism includes a first-stage spray mechanism 7 and a second-stage spray mechanism 8. The first-stage spray mechanism 7 is arranged above the flue gas inlet of the first waste heat boiler 2, and the second-stage spray mechanism 8 is arranged above the flue gas inlet of the wet quenching fire extinguishing chamber 4. In this embodiment, a multi-stage spray mechanism is arranged on the flue gas flow path from the vaporization cooling flue 1 to the wet quenching fire extinguishing chamber 4. The atomized water sprayed by the multi-stage spray mechanism is mixed with the flue gas, absorbs the heat of the flue gas and turns into water vapor. The water vapor enters the next treatment process together with the flue gas. In order to improve the spray In order to achieve the desired effect and ensure the safety of the waste heat recovery system and avoid the risk of flash explosion of converter gas in the range of 605-650°C, a first-level spray mechanism 7 and a second-level spray mechanism 8 are arranged at intervals at the front end of the flue gas inlet of the wet quenching fire extinguishing chamber 4. The front end in this embodiment is in accordance with the flow direction of the flue gas. The sprayed atomized water mixes with the flue gas and enters the wet quenching fire extinguishing chamber 4 together, which can effectively extinguish open flames and reduce the energy of fire particles, ensuring that the flue gas containing high-temperature large particles is quenched and extinguished when it is above 650°C, thereby ensuring the safety of the waste heat recovery system.

[0035] In order to avoid flash explosion of coal gas in the range of 605-650℃, spraying should be started when the flue gas temperature is above 650℃ to ensure that large particles of fire in the flue gas are extinguished by the spraying.

[0036] As one specific embodiment, the first-level spray mechanism 7 is disposed within the vaporization cooling flue 1 and is located near the flue gas inlet of the first waste heat boiler 2. The second-level spray mechanism 8 is disposed within the first waste heat boiler 2 and is located near the flue gas inlet of the wet quenching fire extinguishing chamber 4. The spraying directions of the first-level spray mechanism 7 and the second-level spray mechanism 8 are consistent with the flue gas flow direction. In actual applications, the first-level spray mechanism 7 and the second-level spray mechanism 8 each include multiple dual-medium nozzles evenly distributed throughout the flue gas flow area to ensure that the atomized water can fully contact the flue gas during the spraying process, thereby improving the fire extinguishing effect. The first-level spray mechanism 7 and the second-level spray mechanism 8 can be independently controlled. In some embodiments, more spray mechanisms can be provided according to actual needs to ensure the normal operation of the waste heat recovery system.

[0037] A plurality of temperature sensors and pressure sensors are arranged on the flue gas flow path to monitor the flue gas temperature and pressure in each area to ensure the safe operation of the waste heat recovery system. Preferably, the vaporization cooling flue, the first waste heat boiler, the wet quenching fire extinguishing chamber, and the second waste heat boiler are all provided with temperature sensors and pressure sensors to adjust the multi-stage spray mechanism according to the temperature and pressure of the flue gas.

[0038] Specifically, when the flue gas temperature at the outlet of the vaporization cooling flue 1 is ≥750°C, only the secondary spray mechanism 8 is turned on. When the flue gas temperature at the outlet of the vaporization cooling flue 1 is <750°C, in order to avoid the risk of flash explosion caused by the high-temperature flue gas being directly reduced to below 650°C due to the cooling effect of the first waste heat boiler 2 before the fire is sprayed out, the large-particle fire is not extinguished by the spraying, and only the first-level spray mechanism 7 is turned on at this time; the spraying direction of the first-level spray mechanism 7 and the second-level spray mechanism 8 is consistent with the flue gas flow direction. Spraying can not only extinguish the fire, but also promote the agglomeration of small particles in the flue gas. The small particles agglomerate into large particles, which are more conducive to being captured in the dust removal device 5, thereby improving the dust removal effect.

[0039] In an optimized implementation mode, the first-level spray mechanism 7 and the second-level spray mechanism 8 adopt steam or nitrogen atomized water for spraying, so that the spray water is more dispersed and fine, and can fully contact with the flue gas.

[0040] An optimized implementation manner further includes a second waste heat boiler 6 , which is connected to the flue gas outlet of the dust removal device 5 .

[0041] Optimized implementation method: the smoke outlet of the wet quenching fire extinguishing chamber 4 is connected with a dust removal device 5, the smoke temperature of the outlet of the wet quenching fire extinguishing chamber is 550-600°C, the particulate matter in the smoke is high-temperature particulate matter, and heat can be recovered from it. The dust removal device includes at least one of an inertial dust removal device, a gravity dust removal device, a centrifugal dust removal device and a bag dust removal device, wherein the bag dust removal device is a high-temperature resistant bag dust removal device. According to needs, one or more dust removal devices can be set to remove particulate matter in the smoke and reduce the impact on subsequent pipelines or equipment; the dust removal device 5 is preferably an inertial dust removal device, which removes dust from the smoke and can remove To remove large or small dust particles in the flue gas, a high-temperature ash conveying device 9 is connected below the inertial dust removal device, and a waste heat recovery device 10 is connected to the outlet end of the high-temperature ash conveying device 9. The high-temperature particulate matter captured in the inertial dust removal device is transferred to the waste heat recovery device 10 through the high-temperature ash conveying device 9. The waste heat recovery device 10 can recover the waste heat of the high-temperature particulate matter and recover as much waste heat as possible in the flue gas; preferably, the waste heat recovery device 10 uses water cooling to force heat exchange, and the heated water is comprehensively utilized, and the cooled particulate matter is discharged to the solid waste recovery system for comprehensive treatment; of course, the waste heat recovery device 10 can also adopt heat exchange forms such as gas cooling and natural cooling.

[0042] Preferably, the high-temperature flue gas (flue gas temperature 550-600°C) at the outlet of the inertial dust removal device enters the second waste heat boiler 6 for further waste heat recovery. The outlet flue gas temperature of the second waste heat boiler 6 is ~200°C. The flue gas outlet of the second waste heat boiler 6 is connected to a gas pipeline 11, through which the gas is transported to subsequent equipment for gas purification and recovery. After the flue gas entering the second waste heat boiler passes through the inertial dust removal device, the flue gas is effectively removed of large and small particles in the flue gas, preventing scaling and clogging of the second waste heat boiler and ensuring the stable operation of the waste heat recovery system.

[0043] As one of the specific implementation methods, in order to further purify the flue gas, the flue gas outlet of the gas pipeline 11 can be connected to an electrostatic precipitator or a filter-type dust collector, and the inlet and outlet flue gas temperatures of the second waste heat boiler 6 can be adjusted to meet the temperature requirements of the flue gas entering the gas pipeline 11 and the subsequent dust removal equipment.

[0044] As one of the specific implementation methods, the inlet and outlet flue gas temperatures of the first waste heat boiler 2 can be adjusted according to actual usage requirements, and the first waste heat boiler 2 adopts an extended vaporization cooling flue form; the inlet and outlet flue gas temperatures of the second waste heat boiler 6 can be adjusted according to actual usage requirements, the position of the spray system and the start spraying conditions can be adjusted, and a multi-stage spray system can be set, etc., to achieve waste heat recovery of the flue gas under the premise of ensuring safe operation of the system.

[0045] In an optimized implementation method, the flue gas outlet of the first waste heat boiler 2 is connected to the flue gas inlet of the wet quenching fire extinguishing chamber 4 through a compensator 3 to absorb the thermal displacement of the equipment and avoid damage to the equipment.

[0046] In an optimized implementation method, the first waste heat boiler 2 is a radiation waste heat boiler and a convection waste heat boiler, and / or the second waste heat boiler 6 is a radiation waste heat boiler and a convection waste heat boiler; in this embodiment, the first waste heat boiler 2 is preferably a radiation waste heat boiler, and the second waste heat boiler 6 is preferably a convection waste heat boiler.

[0047] In summary, the flue gas temperature at the outlet of the vaporization cooling flue 1 is 900°C to 1000°C. It enters the radiant waste heat boiler for waste heat recovery. The outlet flue gas temperature of the radiant waste heat boiler is 660°C to 700°C. It is wet-chilled in the wet quenching fire extinguishing chamber 4 by atomized water produced by a multi-stage spray mechanism, bringing the flue gas temperature to a range of 550°C to 600°C. This wet quenching fire extinguishing chamber 4 effectively extinguishes open flames, reduces the energy of ignition particles, and avoids the risk of flash explosions in converter gas within the 605°C to 650°C range. An inertial dust removal device is connected to the flue gas outlet of the wet quenching fire extinguishing chamber 4 for dust removal. The high-temperature, large particles are transported to the waste heat recovery device via the high-temperature ash conveying device 9 below the inertial dust removal device for waste heat recovery. The flue gas at the outlet of the inertial dust removal device enters the convection waste heat boiler for waste heat recovery. The outlet flue gas temperature of the convection waste heat boiler is ~200°C. The flue gas after waste heat recovery is transported to the subsequent device through the gas pipeline for gas purification and recovery. After the flue gas is dedusted by the inertial dust removal device, scaling and clogging of the second waste heat boiler 6 are avoided, and waste heat can be further recovered from high-temperature particulate matter. While ensuring the stable operation of the waste heat recovery system, as much flue gas waste heat as possible is recovered.

[0048] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0049] Those skilled in the art will appreciate that the present invention may be implemented in many other specific forms without departing from the spirit and scope of the present invention. Although embodiments of the present invention have been described, it should be understood that the present invention should not be limited to these embodiments, and those skilled in the art may make changes and modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A converter primary flue gas wet quenching waste heat recovery system, characterized in that: It includes a vaporization cooling flue, a first waste heat boiler, a wet quenching fire extinguishing chamber and a dust removal device which are sequentially connected along the flow direction of the flue gas. A multi-stage spraying mechanism for spraying the flue gas is arranged upstream of the wet quenching fire extinguishing chamber.

2. The converter primary flue gas wet quenching waste heat recovery system according to claim 1 is characterized in that: The multi-stage spray mechanism includes a primary spray mechanism and a secondary spray mechanism. The primary spray mechanism is arranged in the vaporization cooling flue, and the secondary spray mechanism is arranged in the first waste heat boiler.

3. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: A chamber is arranged in the wet quenching fire extinguishing chamber, and a smoke outlet of the wet quenching fire extinguishing chamber is conical and gradually contracts along the smoke flow direction.

4. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: A plurality of explosion relief valves are arranged on the side walls of the wet quenching fire extinguishing chamber.

5. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: It also includes a second waste heat boiler, which is connected to the flue gas outlet of the dust removal device.

6. The converter primary flue gas wet quenching waste heat recovery system according to claim 5, characterized in that: The flue gas outlet of the second waste heat boiler is connected to a gas pipeline.

7. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: The dust removal device is also connected to a high-temperature ash conveying device, and the outlet end of the high-temperature ash conveying device is connected to a waste heat recovery device.

8. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: The smoke outlet of the first waste heat boiler is connected to the smoke inlet of the wet quenching fire extinguishing chamber through a compensator.

9. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: The dust removal device includes at least one of an inertial dust removal device, a gravity dust removal device, a centrifugal dust removal device and a bag dust removal device.

10. The converter primary flue gas wet quenching waste heat recovery system according to claim 1, characterized in that: The first waste heat boiler is one of a radiation waste heat boiler and a convection waste heat boiler, and / or the second waste heat boiler is one of a radiation waste heat boiler and a convection waste heat boiler.

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