Converter steel slag waste heat recovery device and method

Abstract

The application discloses a converter steel slag waste heat recovery device and method, and belongs to the field of steel slag waste heat recovery. The converter steel slag waste heat recovery device comprises a heat sweating pool, a high-temperature waste heat recovery system, a low-temperature waste heat recovery system and a control system. The heat sweating pool is provided with a heat sweating cover at the top, and the heat sweating cover is provided with a temperature sensor and a heat exchange pipe group. The high-temperature waste heat recovery system comprises a first water inlet pipe, a water supply pump, a steam drum and a steam accumulator which are connected in series. The low-temperature waste heat recovery system comprises a water inlet pipeline, a water outlet pipeline and a hot water storage tank. The control system controls the start of the high-temperature waste heat recovery system or the low-temperature waste heat recovery system according to the temperature detected by the temperature sensor. In high temperature, high-temperature steam is recovered to store latent heat, and in low temperature, hot water is recovered to store sensible heat, so that gradient waste heat recovery is realized, the problem of heat source fluctuation caused by intermittent slagging is solved, and the energy utilization rate of the steel production process is improved.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a device and method for recovering waste heat from converter steel slag. Background Technology

[0002] Converter slag is a major byproduct of steel smelting, with my country discharging over 100 million tons annually. Molten steel slag typically reaches temperatures of 1400℃-1600℃. When one ton of steel slag cools from 1400℃ to room temperature, it releases up to 1.6 GJ of heat, equivalent to the heat released by burning 50-60 kg of standard coal. Current technology typically involves pouring the steel slag into a hot quenching tank, adding water for cooling, using temperature stress to crush the slag, and then using a crushing and screening machine to separate the slag from the iron. Simultaneously, a steam recovery system is installed at the top of the hot quenching tank to treat and utilize the steam generated during the quenching process. However, due to the unstable generation of the hot quenching steam, with large fluctuations in pressure and flow, it is difficult to meet the requirements of existing latent heat storage equipment for heat source stability and continuity, resulting in an unstable heat recovery system and low waste heat utilization rate. Summary of the Invention

[0003] The purpose of this invention is to provide a converter slag waste heat recovery device that can stably recover and efficiently utilize waste heat.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A converter slag waste heat recovery device includes a hot quenching tank, a high-temperature waste heat recovery system, a low-temperature waste heat recovery system, and a control system. A hot quenching cover is installed on the top of the hot quenching tank, and the hot quenching cover is equipped with a temperature sensor and a heat exchange tube assembly. The high-temperature waste heat recovery system includes a first inlet pipe, a feedwater pump, a steam drum, and a steam accumulator connected in series. The steam drum has a riser pipe and a downcomer pipe, which are respectively connected to both ends of the heat exchange tube assembly. A feedwater valve is installed on the pipe between the feedwater pump and the steam drum, and a first pipe valve is installed on both the riser pipe and the downcomer pipe. The low-temperature waste heat recovery system includes an inlet pipe, an outlet pipe, and a hot water storage tank. One end of the inlet pipe is connected to… Between the water supply pump and the water supply valve, the other end of the inlet pipe is connected to the downcomer and located between the first pipe valve and the heat exchange tube group. One end of the outlet pipe is connected to the inlet pipe and located between the first pipe valve and the heat exchange tube group. The other end of the outlet pipe is connected to the hot water storage tank. A second pipe valve is provided on both the inlet pipe and the outlet pipe. The control system is communicatively connected to the temperature sensor and electrically connected to the water supply pump, the water supply valve, the first pipe valve, and the second pipe valve, respectively. The control system controls the start of the high-temperature waste heat recovery system or the low-temperature waste heat recovery system according to the temperature detected by the temperature sensor.

[0006] Preferably, the heat exchanger tube assembly includes a water-side header, a steam-side header, and multiple U-shaped heat exchange tubes. The multiple U-shaped heat exchange tubes are spaced apart along the length of the water-side header. One end of the multiple U-shaped heat exchange tubes is fixedly connected to the water-side header, and the other end of the multiple U-shaped heat exchange tubes is fixedly connected to the steam-side header. The water-side header is connected to the downcomer flange, and the steam-side header is connected to the riser flange.

[0007] Preferably, the sidewall of the U-shaped heat exchange tube is provided with heat exchange fins, which protrude radially along the U-shaped heat exchange tube.

[0008] Preferably, the heat exchanger cover has a downward-facing accommodating cavity, which has multiple tube sheets arranged at intervals along the length of the U-shaped heat exchange tubes. The multiple U-shaped heat exchange tubes are all located in the accommodating cavity, and each U-shaped heat exchange tube is fixedly connected to the multiple tube sheets.

[0009] Preferably, the detection end of the temperature sensor is located inside the accommodating cavity and is at the same height as the water-side header.

[0010] Preferably, the converter slag waste heat recovery device further includes a second water inlet pipe with a high-pressure pump and multiple cleaning pipe groups. Each cleaning pipe group includes a main pipe, multiple branch pipes, and multiple cleaning nozzles. The multiple branch pipes are connected to the same main pipe and pass through the top wall of the heat exchange cover. The cleaning nozzles and branch pipes are connected in a one-to-one correspondence. The cleaning nozzles are located inside the accommodating cavity and above the heat exchange pipe groups. The main pipes of the multiple cleaning pipe groups are all connected to the second water inlet pipe, and the cleaning nozzles of the multiple cleaning pipe groups are arranged in a matrix.

[0011] Preferably, the cleaning nozzle is a multi-directional jet nozzle.

[0012] Preferably, the output end of the hot water storage tank is connected to a water use unit, which includes an industrial water station and a heating heat exchange station.

[0013] Preferably, a circulation pump is provided on the downcomer, and the circulation pump is located on the side of the first pipe valve away from the water inlet pipe.

[0014] The purpose of this invention is to provide a method for recovering waste heat from converter steel slag, ensuring accurate and efficient recovery of waste heat by the system.

[0015] To achieve this objective, the present invention adopts the following technical solution:

[0016] A method for recovering waste heat from converter slag, applied to the aforementioned converter slag waste heat recovery device, comprising:

[0017] The waste heat temperature detected by the temperature sensor is obtained, and it is determined whether the waste heat temperature is within the preset temperature range. If so, the waste heat temperature is compared with the preset high temperature.

[0018] If the waste heat temperature is greater than or equal to the preset high temperature, then the high temperature waste heat recovery mode is entered. In the high temperature waste heat recovery mode, the water supply pump, the water supply valve and the first pipe valve are opened, and the second pipe valve is closed.

[0019] If the waste heat temperature is lower than the preset high temperature, then the low temperature waste heat recovery mode is entered. In the low temperature waste heat recovery mode, the water supply pump and the second pipe valve are opened, and the water supply valve and the first pipe valve are closed.

[0020] The beneficial effects of this invention are as follows: When the waste heat recovery device is running, the control system acquires the temperature detected by the temperature sensor to determine the temperature level in the hot quenching pool. When the temperature in the hot quenching pool is high, the control system activates the high-temperature waste heat recovery system. At this time, the control system controls the water pump, water valve, and first pipe valve to open. The water pump pressurizes the external circulating medium and pumps it into the steam drum through the first inlet pipe. The water pump then enters the heat exchange tube group through the first pipe valve on the downcomer. The circulating medium evaporates after exchanging heat with the high-temperature steam in the hot quenching pool in the heat exchange tube group. The evaporated circulating medium passes through the riser pipe and the steam drum in sequence and finally enters the steam accumulator. After being regulated by the steam accumulator, saturated steam is stably output. When the temperature in the hot quenching pool is low, the control system activates the low-temperature waste heat recovery system. At this time, the control system controls the water pump and second pipe valve to open. The water pump directly pumps the external circulating medium into the heat exchange tube group through the inlet pipe. The circulating medium heats up after exchanging heat with the medium- and low-temperature steam in the hot quenching pool in the heat exchange tube group. The heated circulating medium enters the hot water storage tank through the outlet pipe. After being regulated by the hot water storage tank, hot water is stably output. By installing heat exchange tube assemblies, steam accumulators, and hot water storage tanks, the circulating medium within the heat exchange tube assemblies exchanges heat with the steam radiation in the hot quenching pool. At high temperatures, the latent heat of the high-temperature steam is recovered and stored; at low temperatures, the sensible heat of the hot water is recovered and stored. This achieves gradient waste heat recovery, solving the problem of heat source fluctuations caused by intermittent slag discharge. It can not only produce saturated steam for power generation or external sale, but also produce hot water for production or heating, reducing the waste of steel slag waste heat resources, improving the energy utilization rate of the steel production process, and reducing carbon emissions. Simultaneously, the entire process is automated through a control system, reducing manual intervention and effectively improving the intelligence and control precision of the waste heat recovery device.

[0021] This application also provides a method for recovering waste heat from converter steel slag, which automatically switches between different heat recovery modes according to different temperatures in the hot quenching pool, thereby absorbing waste heat in various temperature ranges, improving the stability of system operation and increasing waste heat recovery efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the converter slag waste heat recovery device according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the structure of the heat seal cover according to an embodiment of this application;

[0024] Figure 3 This is a side view of the heat seal cover according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the structure of the U-shaped heat exchange tube according to an embodiment of this application;

[0026] Figure 5 This is a flowchart illustrating the steps of the converter slag waste heat recovery method according to an embodiment of this application.

[0027] In the picture:

[0028] 1. Hot and stuffy pool;

[0029] 2. Heat exchanger cover; 21. Temperature sensor; 22. Heat exchanger tube assembly; 221. Water-side header; 222. Steam-side header; 223. U-shaped heat exchanger tube; 2231. Heat exchanger fins; 224. Fittings; 23. Receptacle; 24. Tube sheet;

[0030] 3. High-temperature waste heat recovery system; 31. First water inlet pipe; 32. Feed water pump; 33. Steam drum; 331. Riser pipe; 332. Downcomer pipe; 333. First valve; 334. Circulation pump; 34. Steam accumulator; 35. Feed water valve;

[0031] 4. Low-temperature waste heat recovery system; 41. Inlet pipe; 42. Outlet pipe; 43. Hot water storage tank; 431. Industrial water station; 432. Heating heat exchange station; 433. User hot water network; 434. Hot water outlet valve; 435. Heating water valve; 44. Second pipe valve;

[0032] 5. Second water inlet pipe; 51. Cleaning pipe assembly; 511. Main pipe; 512. Branch pipe; 513. Cleaning nozzle; 52. High-pressure pump;

[0033] 6. Third water inlet pipe; 61. Water supply pipe; 62. Spiral nozzle. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0035] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0038] Reference Figures 1 to 4As shown, a converter slag waste heat recovery device (hereinafter referred to as waste heat recovery device) provided according to an embodiment of this application includes a hot quenching tank 1, a high-temperature waste heat recovery system 3, a low-temperature waste heat recovery system 4, and a control system. The hot quenching tank 1 is provided with an openable and closable feeding port, and a slag discharge port is provided at the bottom of the hot quenching tank 1. A hot quenching cover 2 is provided at the top opening of the hot quenching tank 1. The hot quenching cover 2 is rectangular in its orthographic projection on the horizontal plane. A temperature sensor 21 is provided on the side wall of the hot quenching cover 2. A heat exchange tube group 22 is provided on the side of the hot quenching cover 2 facing the hot quenching tank 1. The hot quenching cover 2 is also provided with multiple water supply pipes 61. The water supply pipes 61 are connected to an external third water inlet pipe 6 and are provided with at least one spiral nozzle 62. The spiral nozzles 62 of the multiple water supply pipes 61 are arranged in a matrix and located below the heat exchange tube group 22. The high-temperature waste heat recovery system 3 includes a first inlet pipe 31, a feed water pump 32, a steam drum 33, and a steam accumulator 34 connected in series. The steam drum 33 is equipped with a riser pipe 331 and a downcomer pipe 332, which are respectively connected to both ends of the heat exchange tube group 22. A feed water valve 35 is provided on the pipe between the feed water pump 32 and the steam drum 33. A first pipe valve 333 is provided on both the riser pipe 331 and the downcomer pipe 332. The low-temperature waste heat recovery system 4 includes an inlet pipe 41, an outlet pipe 42, and a hot water storage tank 43. One end of the inlet pipe 41 is connected between the feed water pump 32 and the feed water valve 35, and the other end of the inlet pipe 41 is connected to the downcomer pipe 332 and located between the first pipe valve 333 and the heat exchange tube group 22. That is, the inlet pipe 41 is connected in parallel with the steam drum 33 through the pipe where the feed water valve 35 is located and the downcomer pipe 332. One end of the outlet pipe 42 is connected to the inlet pipe 41 and is located between the first pipe valve 333 and the heat exchange tube group 22. The other end of the outlet pipe 42 is connected to the hot water storage tank 43. A second pipe valve 44 is provided on both the inlet pipe 41 and the outlet pipe 42. The control system is communicatively connected to the temperature sensor 21 and electrically connected to the water pump 32, the water valve 35, the first pipe valve 333, and the second pipe valve 44, respectively. The control system controls the activation of the high-temperature waste heat recovery system 3 or the low-temperature waste heat recovery system 4 based on the temperature detected by the temperature sensor 21. In this embodiment, the control system can be a centralized or distributed controller. For example, the controller can be a single microcontroller or a combination of multiple distributed microcontrollers. The microcontroller can run a control program to control the water pump 32, the water valve 35, the first pipe valve 333, and the second pipe valve 44 to achieve their functions.

[0039] Understandably, when the slag in the hot quenching tank 1 is full, the waste heat recovery device starts the hot quenching operation, and the third water inlet pipe 6 starts to supply water into the water supply pipe 61. The water is then sprayed through the spiral nozzle 62 connected to the hot quenching water supply pipe 61 to cool the slag. The control system obtains the temperature detected by the temperature sensor 21 to determine the temperature level in the hot quenching tank 1. When the temperature in the hot quenching tank 1 is high, the control system activates the high-temperature waste heat recovery system 3. At this time, the control system controls the water pump 32, the water valve 35, and the first pipe valve 333 to open. The water pump 32 pressurizes the external circulating medium (deoxygenated water in this embodiment) into the steam drum 33 through the first water inlet pipe 31. The circulating medium then enters the heat exchange tube group 22 through the first pipe valve 333 on the downcomer 332. The circulating medium evaporates after exchanging heat with the high-temperature steam in the hot quenching tank 1 in the heat exchange tube group 22. The evaporated circulating medium... The medium passes through the riser pipe 331 and the steam drum 33 in sequence and finally enters the steam accumulator 34. After being regulated by the steam accumulator 34, saturated steam is stably output. When the temperature in the hot quenching pool 1 is low, the control system starts the low temperature waste heat recovery system 4. At this time, the control system controls the water pump 32 and the second pipe valve 44 to open. The water pump 32 pumps the external circulating medium directly into the heat exchange tube group 22 through the water inlet pipe 41. The circulating medium is heated after exchanging heat with the medium and low temperature steam in the hot quenching pool 1 in the heat exchange tube group 22. The heated circulating medium enters the hot water storage tank 43 through the water outlet pipe 42. After being regulated by the hot water storage tank 43, hot water is stably output.

[0040] By setting up a heat exchange tube assembly 22, a steam accumulator 34, and a hot water storage tank 43, the circulating medium in the heat exchange tube assembly 22 exchanges heat with the steam radiation in the hot slag chamber 1. At high temperatures, the latent heat of the high-temperature steam is recovered and stored; at low temperatures, the sensible heat of the hot water is recovered and stored, achieving gradient waste heat recovery. This solves the problem of heat source fluctuations caused by intermittent slag discharge. It can not only produce saturated steam for power generation or external sale, but also produce hot water for production or heating, reducing the waste of steel slag waste heat resources, improving the energy utilization rate of the steel production process, reducing carbon emissions, and significantly improving the efficiency of steel slag waste heat recovery. Simultaneously, the entire process is automated through a control system, reducing manual intervention and effectively improving the intelligence and control accuracy of the waste heat recovery device. Furthermore, temperature detection and radiant heat recovery functions are integrated into the hot slag chamber 2 to form an integrated structure, saving space and improving the integration and functionality of the hot slag chamber 2.

[0041] Reference Figure 2 and Figure 3As shown, it can be understood that the heat exchanger tube assembly 22 includes a water-side header 221, a steam-side header 222, and multiple U-shaped heat exchanger tubes 223. The water-side header 221 and the steam-side header 222 are two parallel tubular or strip-shaped components. The multiple U-shaped heat exchanger tubes 223 are spaced apart along the length of the water-side header 221. The same end of the multiple U-shaped heat exchanger tubes 223 is fixedly connected to the same side of the water-side header 221, and the other end of the multiple U-shaped heat exchanger tubes 223 is fixedly connected to the same side of the steam-side header 222. The other side of the water-side header 221 is connected to the downcomer 332 flange through a fitting 224, and the other side of the steam-side header 222 is connected to the riser 331 flange through another fitting 224.

[0042] The U-shaped heat exchange tubes 223 are connected at both ends to the water-side header 221 and the steam-side header 222, respectively, realizing the separation of functions for water distribution and steam collection. The water-side header 221 can evenly distribute the circulating medium to each U-shaped heat exchange tube 223, while the steam-side header 222 is responsible for collecting and outputting the steam generated by each U-shaped heat exchange tube 223. The water-side header 221 and the steam-side header 222 have a compact structure and low flow resistance. By setting the U-shaped heat exchange tubes 223, the flow path of the circulating medium can be extended, the heat exchange area can be increased, and the water can fully absorb the radiant heat of the steel slag when flowing in the heat exchange tubes, effectively improving the heat exchange efficiency.

[0043] It should be added that the U-shaped heat exchange tube 223 is usually made of corrosion-resistant materials such as S31603, S31254, and N08904 to enhance the corrosion resistance of the heat exchange tube assembly 22 in high dust and acidic environments.

[0044] Preferably, the detection end of the temperature sensor 21 is located inside the accommodating cavity 23 and is at the same height as the water-side header 221.

[0045] By placing the detection end of temperature sensor 21 at the same horizontal plane as the water-side header 221, temperature sensor 21 can accurately detect the temperature of steel slag radiated onto the heat exchange surface of U-shaped heat exchange tube 223. Compared to placing the sensor at other locations such as the top or bottom of the accommodating cavity 23, arranging temperature sensor 21 at the same height as the water-side header 221 (water inlet end of U-shaped heat exchange tube 223) avoids temperature measurement deviations caused by hot air rising or cold air sinking, ensuring the accuracy and reliability of temperature data.

[0046] Reference Figure 4 As shown, it can be understood that the sidewall of the U-shaped heat exchange tube 223 is provided with heat exchange fins 2231, which protrude radially along the U-shaped heat exchange tube 223. It should be added that, since the U-shaped heat exchange tube 223 is U-shaped, to facilitate processing and reduce costs, the heat exchange fins 2231 can be provided only on the straight tube sidewalls at both ends of the U-shaped heat exchange tube 223.

[0047] By incorporating heat exchange fins 2231, on the one hand, the effective heat exchange area can be increased, improving the heat exchange capacity per unit volume and further enhancing the recovery efficiency of radiant heat from the steel slag. On the other hand, the heat exchange fins 2231 form a physical barrier on the outside of the U-shaped heat exchange tube 223, preventing direct contact between the high-temperature steel slag and the tube wall, thereby reducing direct scouring and wear of the tube. Furthermore, the heat exchange fins 2231 prevent the formation of a dense scale layer on the tube wall, facilitating subsequent cleaning operations and promoting the long-term stable operation of the waste heat recovery device in high-dust environments.

[0048] Reference Figure 3 As shown, it can be understood that the heat vent 2 has a downward-facing accommodating cavity 23, and the accommodating cavity 23 has multiple tube sheets 24 arranged at intervals along the length direction of the U-shaped heat exchange tubes 223. The tube sheets 24 are welded and fixed to the heat vent 2, and the multiple U-shaped heat exchange tubes 223 are all located in the accommodating cavity 23, and each U-shaped heat exchange tube 223 is fixedly connected to multiple tube sheets 24.

[0049] By setting tube sheets 24, the tube sheets 24 can support and position the U-shaped heat exchange tubes 223, preventing the U-shaped heat exchange tubes 223 from deforming or sagging under high temperature environment and gravity. Multiple tube sheets 24 work together to fix the U-shaped heat exchange tubes 223 from multiple points, improve the overall structural rigidity of the heat exchange tube group 22, and resist the impact and vibration generated during steel slag dumping and heat quenching, effectively improving the installation stability of the U-shaped heat exchange tubes 223.

[0050] Reference Figures 1 to 3 As shown, it can be understood that the converter slag waste heat recovery device also includes a second water inlet pipe 5 with a high-pressure pump 52 and multiple cleaning pipe groups 51. The cleaning pipe group 51 includes a main pipe 511, multiple branch pipes 512 and multiple cleaning nozzles 513. Multiple branch pipes 512 are connected to the same main pipe 511 and pass through the top wall of the heat exchanger cover 2. The cleaning nozzles 513 and branch pipes 512 are connected one-to-one. The cleaning nozzles 513 are located in the accommodating cavity 23 and above the heat exchange pipe group 22. The main pipes 511 of the multiple cleaning pipe groups 51 are all connected to the second water inlet pipe 5. The cleaning nozzles 513 of the multiple cleaning pipe groups 51 are arranged in a matrix.

[0051] After a period of use, sticky dust may accumulate on the surface of the U-shaped heat exchange tubes 223 of the waste heat recovery device, requiring regular cleaning, such as once every 24 hours. When the waste heat recovery device requires cleaning, the control system enters the cleaning mode, water enters through the second inlet pipe 5, and the cleaning water is pressurized to 10MPa-30MPa by the high-pressure pump 52 and enters the main pipe 511. The cleaning nozzles 513 connected through the branch pipe 512 clean the U-shaped heat exchange tubes 223, preventing dust accumulation in the dead zones of the U-shaped heat exchange tubes 223, effectively extending the maintenance cycle and service life of the heat exchange tube assembly 22, and ensuring the long-term stable operation of the waste heat recovery device.

[0052] Preferably, the cleaning nozzle 513 is a multi-directional jet nozzle.

[0053] By setting up a multi-directional jet nozzle, the multi-directional jet nozzle can generate multiple jets in different directions during spraying. Compared with a single-direction nozzle, it has a wider cleaning coverage and fewer cleaning dead spots. It can flush the surfaces of the U-shaped heat exchange tube 223 and heat exchange fins 2231 from multiple angles, thoroughly removing the accumulated dust. While ensuring the cleaning effect, it avoids the erosion damage that a single-direction high-pressure jet may cause to the surface of the heat exchange tube.

[0054] Reference Figure 1 As shown, it can be understood that the output end of the hot water storage tank 43 is connected to a water-using unit, which includes an unconnected industrial water station 431 and a heating heat exchange station 432 (the heating heat exchange station 432 is connected in parallel with the user's hot water network 433). A hot water outlet valve 434 is installed on the pipeline between the hot water storage tank 43 and the industrial water station 431, and a heating water valve 435 is installed on the pipeline between the hot water storage tank 43 and the heating heat exchange station 432. When the low-temperature waste heat recovery system 4 is started, the pressure control process of the circulating medium is as follows: the deoxygenated water from the boundary area is pressurized to 0.6MPa-0.8MPa by the feed water pump 32, and then enters the hot water storage tank 43 through the low-temperature waste heat recovery system 4, with an output hot water pressure of 0.5MPa-0.7MPa.

[0055] Hot water storage tank 43 is connected to both industrial water station 431 and heating heat exchange station 432. During the non-heating season, hot water can be directly supplied to industrial water station 431 for production use; during the heating season, the hot water can be switched to heating heat exchange station 432, where heat is transferred to user hot water network 433 via heat exchangers to provide heating services for the factory area or surrounding areas. This parallel design gives the low-temperature waste heat recovery system 4 great flexibility and adaptability, allowing the recovered heat energy to be flexibly switched between different uses according to the season and actual needs, achieving optimal allocation and maximum utilization of waste heat resources.

[0056] In some embodiments, a circulation pump 334 is provided on the downcomer 332, and the circulation pump 334 is located on the side of the first pipe valve 333 away from the inlet pipe 41.

[0057] When the high-temperature waste heat recovery system 3 is started, the pressure control process of the circulating medium is as follows: the deoxygenated water pressure from the boundary area is 0.2MPa-0.4MPa, which is boosted to 1.2MPa-1.6MPa by the feed water pump 32. The circulating pump 334 boosts the water pressure of the downcomer 332 by 0.1MPa-0.5MPa to overcome resistance loss. The steam pressure in the riser 331 is controlled at 1.2MPa-1.6MPa. The steam pressure output from the steam drum 33 is 1.2MPa-1.6MPa. The steam pressure output from the steam accumulator 34 is controlled at 0.8MPa-1.2MPa. By setting up a circulating pump 334, in the high-temperature waste heat recovery mode, the circulating pump 334 actively drives the saturated water in the steam drum 33 to enter the heat exchange tube group 22 through the downcomer 332. After absorbing the radiant heat of the steel slag, it generates steam. The steam returns to the steam drum 33 through the riser 331. The forced circulation method ensures that even if the heat source fluctuates or the natural circulation power is insufficient, the system can still maintain a stable steam-water circulation, thus ensuring the continuity and reliability of waste heat recovery.

[0058] Reference Figure 5 As shown, a converter slag waste heat recovery method according to an embodiment of this application, applied to the aforementioned converter slag waste heat recovery device, includes:

[0059] S1. Obtain the residual heat temperature detected by the temperature sensor 21, determine whether the residual heat temperature is within the preset temperature range, and if so, compare the residual heat temperature with the preset high temperature.

[0060] Specifically, in this embodiment, 200℃ is defined as the high and low temperature differentiation temperature, and 100℃ is defined as the effective waste heat differentiation temperature. The radiant heat temperature of the hot storage pool 1 above 200℃ is considered high-temperature waste heat, 100℃-200℃ is considered low-temperature waste heat, and below 100℃ is considered non-recoverable waste heat with no recovery value. The control system can determine whether to perform subsequent recovery operations based on the waste heat temperature detected by the temperature sensor 21. If the waste heat temperature is greater than or equal to 100℃, it is determined that waste heat recovery is necessary; if it is less than 100℃, the waste heat recovery device will stop operating.

[0061] S2. When the temperature of the steel slag in the hot quenching tank 1 is high (the temperature detected by temperature sensor 21 is ≥ the preset high temperature, for example ≥ 200℃), the control system enters the high-temperature waste heat recovery mode. In the high-temperature waste heat recovery mode, the feed water pump 32, feed water valve 35 and the first pipe valve 333 are opened, and the second pipe valve 44 is closed. At this time, the changes in the circulating medium and pressure in the high-temperature waste heat recovery system 3 are as follows:

[0062] Steam-water flow: Deoxygenated water comes from the boundary area, enters the steam drum 33 through the first inlet pipe 31, feed water pump 32, feed water valve 35, and then enters the steam drum 33. The deoxygenated water in the steam drum 33 enters the downcomer 332, passes through the circulation pump 334 and the first pipe valve 333, and enters the heat exchange tube group 22 above the hot quenching pool 1 to absorb the high-temperature waste heat in the hot quenching pool 1, generating medium-pressure saturated steam. The steam returns to the steam drum 33 through the riser pipe 331 and another first pipe valve 333. The steam in the steam drum 33 is output to the steam accumulator 34, where it is regulated and then stably output as saturated steam.

[0063] Pressure control: The deoxygenated water pressure from the boundary area is 0.2MPa-0.4MPa, which is boosted to 1.2MPa-1.6MPa by the feed water pump 32. The circulating pump 334 boosts the water pressure from the downcomer 332 by 0.1-0.5MPa to overcome resistance loss. The steam pressure in the riser 331 is controlled at 1.2MPa-1.6MPa. The steam pressure output from the steam drum 33 is 1.2MPa-1.6MPa. The steam pressure output from the steam accumulator 34 is controlled at 0.8MPa-1.2MPa.

[0064] S3. When the slag temperature in the hot quenching tank 1 is low but still has recycling value (minimum recoverable residual temperature ≤ temperature detected by temperature sensor 21 ≤ preset high temperature), the control system enters the low-temperature waste heat recovery mode. In the low-temperature waste heat recovery mode, the feed water pump 32 and the second pipe valve 44 are opened, and the feed water valve 35 and the first pipe valve 333 are closed. At this time, the changes in the circulating medium and pressure in the low-temperature waste heat recovery system 4 are as follows:

[0065] The hot water process is as follows: Deoxygenated water comes from the boundary area, enters through the first inlet pipe 31, passes through the water supply pump 32 and the second pipe valve 44, and enters the heat exchange tube group 22 above the hot quenching pool 1. It absorbs the low-temperature waste heat in the hot quenching pool 1 to produce hot water, which then passes through another second pipe valve 44 to the hot water storage tank 43. After regulation, the hot water is output stably. The hot water has two usage paths: one is to be directly output to the production water point via the hot water outlet valve 434; the other is to be sent to the heating heat exchange station 432 via the heating water valve 435, where it exchanges heat with the incoming water from the user's hot water pipe network 433 before being transported to the boundary area.

[0066] Pressure control: The deoxygenated water from the boundary area is at a pressure of 0.2MPa-0.4MPa. It is boosted to 0.6MPa-0.8MPa by the water supply pump 32 and enters the hot water storage tank 43 through the heat exchange tube group 22. The output hot water pressure is 0.5MPa-0.7MPa.

[0067] Understandably, the method automatically switches between different heat recovery modes based on varying temperatures within the hot quenching pool 1. This simple and efficient control strategy eliminates the need for complex mathematical models and extensive computational resources, resulting in low cost, fast response, and high reliability. It effectively solves the problems of complex control logic and high implementation costs in existing technologies. Furthermore, this method incorporates the waste heat from the entire cooling process of the steel slag from high to low temperature into the recovery scope, achieving full-temperature-range waste heat recovery, significantly improving energy utilization efficiency and reducing carbon emissions.

[0068] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A converter slag waste heat recovery device, characterized in that, include: A hot sump (1) is provided with a hot sump cover (2) on top. The hot sump cover (2) is equipped with a temperature sensor (21) and a heat exchange tube assembly (22). The high-temperature waste heat recovery system (3) includes a first inlet pipe (31), a feed water pump (32), a steam drum (33), and a steam accumulator (34) connected in series. The steam drum (33) is provided with a riser pipe (331) and a downcomer pipe (332). The riser pipe (331) and the downcomer pipe (332) are respectively connected to both ends of the heat exchange tube group (22). A feed water valve (35) is provided on the pipe between the feed water pump (32) and the steam drum (33). A first pipe valve (333) is provided on both the riser pipe (331) and the downcomer pipe (332). The low-temperature waste heat recovery system (4) includes an inlet pipe (41), an outlet pipe (42), and a hot water storage tank (43). One end of the inlet pipe (41) is connected between the water supply pump (32) and the water supply valve (35). The other end of the inlet pipe (41) is connected to the downcomer (332) and located between the first pipe valve (333) and the heat exchange tube group (22). One end of the outlet pipe (42) is connected to the inlet pipe (41) and located between the first pipe valve (333) and the heat exchange tube group (22). The other end of the outlet pipe (42) is connected to the hot water storage tank (43). A second pipe valve (44) is provided on both the inlet pipe (41) and the outlet pipe (42). The control system is communicatively connected to the temperature sensor (21) and electrically connected to the water pump (32), the water valve (35), the first pipe valve (333) and the second pipe valve (44) respectively. The control system controls the start of the high-temperature waste heat recovery system (3) or the low-temperature waste heat recovery system (4) according to the temperature detected by the temperature sensor (21).

2. The converter slag waste heat recovery device according to claim 1, characterized in that, The heat exchange tube assembly (22) includes a water-side header (221), a steam-side header (222), and a plurality of U-shaped heat exchange tubes (223). The plurality of U-shaped heat exchange tubes (223) are spaced apart along the length of the water-side header (221). The same end of the plurality of U-shaped heat exchange tubes (223) is fixedly connected to the water-side header (221), and the other end of the plurality of U-shaped heat exchange tubes (223) is fixedly connected to the steam-side header (222). The water-side header (221) is flange-connected to the downcomer (332), and the steam-side header (222) is flange-connected to the riser (331).

3. The converter slag waste heat recovery device according to claim 2, characterized in that, The sidewall of the U-shaped heat exchange tube (223) is provided with heat exchange fins (2231), which protrude radially along the U-shaped heat exchange tube (223).

4. The converter slag waste heat recovery device according to claim 2 or 3, characterized in that, The heat seal cover (2) is provided with a downward-facing accommodating cavity (23). The accommodating cavity (23) is provided with a plurality of tube sheets (24) arranged at intervals along the length direction of the U-shaped heat exchange tube (223). The plurality of U-shaped heat exchange tubes (223) are all located in the accommodating cavity (23), and each U-shaped heat exchange tube (223) is fixedly connected to the plurality of tube sheets (24).

5. The converter slag waste heat recovery device according to claim 4, characterized in that, The detection end of the temperature sensor (21) is located inside the accommodating cavity (23) and is at the same height as the water-side header (221).

6. The converter slag waste heat recovery device according to claim 4, characterized in that, The converter slag waste heat recovery device also includes a second water inlet pipe (5) with a high-pressure pump (52) and multiple cleaning pipe groups (51). The cleaning pipe group (51) includes a main pipe (511), multiple branch pipes (512) and multiple cleaning nozzles (513). Multiple branch pipes (512) are connected to the same main pipe (511) and pass through the top wall of the heat exchange cover (2). The cleaning nozzles (513) and branch pipes (512) are connected one-to-one. The cleaning nozzles (513) are located in the accommodating cavity (23) and above the heat exchange pipe group (22). The main pipes (511) of multiple cleaning pipe groups (51) are all connected to the second water inlet pipe (5). The cleaning nozzles (513) of multiple cleaning pipe groups (51) are arranged in a matrix.

7. The converter slag waste heat recovery device according to claim 6, characterized in that, The cleaning nozzle (513) is a multi-directional jet nozzle.

8. The converter slag waste heat recovery device according to claim 1, characterized in that, The output end of the hot water storage tank (43) is connected to a water use unit, which includes an industrial water station (431) and a heating exchange station (432).

9. The converter slag waste heat recovery device according to claim 1, characterized in that, A circulation pump (334) is provided on the downcomer (332), and the circulation pump (334) is located on the side of the first pipe valve (333) away from the water inlet pipe (41).

10. A method for recovering waste heat from converter slag, applied to the converter slag waste heat recovery device according to any one of claims 1-9, characterized in that, include: Obtain the residual heat temperature detected by the temperature sensor (21), determine whether the residual heat temperature is within the preset temperature range, and if so, compare the residual heat temperature with the preset high temperature. If the waste heat temperature is greater than or equal to the preset high temperature, then enter the high temperature waste heat recovery mode. In the high temperature waste heat recovery mode, open the water pump (32), the water valve (35) and the first pipe valve (333), and close the second pipe valve (44). If the waste heat temperature is lower than the preset high temperature, then the low temperature waste heat recovery mode is entered. In the low temperature waste heat recovery mode, the water supply pump (32) and the second pipe valve (44) are opened, and the water supply valve (35) and the first pipe valve (333) are closed.

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