A molten steel slag gasification cooling waste heat recovery system and method

Abstract

The application provides a molten steel slag gasification cooling waste heat recovery system and method, and the system comprises: a steel slag crushing area; a steel slag storage plate arranged in the steel slag crushing area; a heat exchange pipeline laid below the steel slag storage plate; a steam pocket connected with the heat exchange pipeline through a circulating pipeline; and a water pump connected with the steam pocket through a pipeline and providing circulating water for the steam pocket; in this way, in the steel slag roller crushing stage, the heat exchange pipeline is laid below the steel slag crushing area, and the steam pocket provides circulating water for the heat exchange pipeline, the water in the heat exchange pipeline is heated by the steel slag heat, and pure steam is formed, so that the steel slag waste heat can be effectively recovered, and the resource utilization rate is improved.

Description

Technical Field

[0001] This application relates to the field of waste heat recovery technology, and in particular to a waste heat recovery system and method for molten steel slag gasification cooling. Background Technology

[0002] The recovery and utilization of waste heat resources from steel enterprises has always been a focus of attention in the metallurgical industry worldwide. Currently, most steel enterprises, both domestically and internationally, first cool the high-temperature molten slag appropriately before processing it, extracting the metals for use as materials; however, the problem of recovering and utilizing the sensible heat of steel slag has not been effectively solved.

[0003] Currently, the steel slag roller crushing-pressurized hot quenching technology is increasingly being adopted by more and more companies because it is suitable for processing steel slag of various temperatures and fluidities. However, the sensible heat recovery technology for steel slag is not actually applied in the roller crushing stage. Generally, a weak water cooling process is used during the roller crushing of steel slag, which generates relatively little steam, and this steam cannot be recovered in an open state.

[0004] Some companies have proposed using air cooling to utilize the heat from steel slag during the roller crushing process. This involves sealing the steel slag in a space and then using air cooling to exchange and extract the heat. However, this technology requires placing the roller crushing equipment in an enclosed space, where the high-temperature environment can easily damage the equipment.

[0005] Therefore, existing technologies cannot recover the heat during the roller crushing stage of steel slag, resulting in a 30% loss of heat from the steel slag during this stage. Furthermore, although steam and hot water can be recovered during the pressurized hot simmering stage, the steam and hot water have a high dust content because they are in direct contact with the steel slag, making subsequent use difficult. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a system and method for recovering waste heat from the gasification and cooling of molten steel slag, in order to solve or partially solve the technical problem of resource waste caused by the inability to effectively recover the waste heat of steel slag during the roller crushing stage in the prior art.

[0007] This invention provides a waste heat recovery system for the gasification and cooling of molten steel slag, the system comprising:

[0008] Steel slag crushing equipment;

[0009] A steel slag storage plate is placed below the steel slag crushing equipment;

[0010] Heat exchange pipes are laid beneath the steel slag storage plate;

[0011] The steam package is connected to the heat exchange pipeline via a circulation pipeline;

[0012] A water pump is connected to the steam generator via a pipeline to provide circulating water to the steam generator.

[0013] In the above scheme, the steel slag crushing equipment is placed on the steel slag storage plate for crushing and spreading the steel slag.

[0014] In the above scheme, the circulation pipeline includes: a first pipeline and a second pipeline; the steam package includes:

[0015] The first water level area is connected to one end of the first pipeline;

[0016] The second water level area is connected to one end of the second pipeline;

[0017] A baffle plate is located between the first water level area and the second water level area; wherein,

[0018] The water level in the second water level area is lower than the water level in the first water level area.

[0019] In the above scheme, the heat exchange pipeline includes: an upper water collection pipe and a lower water collection pipe; wherein,

[0020] The upper water collection pipe is connected to the other end of the second pipe;

[0021] The lower water collection pipe is connected to the other end of the first pipe.

[0022] In the above scheme, the system further includes: a first deaerator;

[0023] One end of the first deaerator is connected to the first water level zone via a third pipe;

[0024] The other end of the first deaerator is connected to the second water level zone via a fourth pipe.

[0025] In the above scheme, the system further includes:

[0026] The first drain pipe has one end connected to the first water level area and the other end connected to the third pipe.

[0027] The second drain pipe has one end connected to the second water level area and the other end connected to the third pipe.

[0028] In the above scheme, the system also includes a slag outlet, located at one end of the steel slag crushing equipment.

[0029] The present invention also provides a method for recovering waste heat from the gasification and cooling of molten steel slag, applied in any of the above-described systems, the method comprising:

[0030] Demineralized water is pumped into the steam package using a water pump, and the first valve on the second pipeline is opened to form a water circulation.

[0031] The steel slag to be processed is poured from the slag hopper onto the steel slag storage plate. The heat of the steel slag is used to heat the water in the heat exchange pipeline and generate steam, which then enters the steam boiler.

[0032] When the steam pressure inside the steam chamber is determined to be greater than the pressure threshold, the steam valve on the steam chamber is opened to send the steam into the steam pipeline network.

[0033] In the above scheme, before pumping demineralized water into the steam package using a water pump and controlling the opening of the first valve on the second pipeline to form a water circulation, the method further includes:

[0034] Control the opening of the first valve on the second pipeline and the second valve on the first pipeline;

[0035] Demineralized water is pumped into the first water level area of ​​the steam package using a water pump, and the demineralized water in the first water level area is transported to the second water level area using the siphon principle.

[0036] When it is determined that the liquid level in the second water level zone has reached the first working water level, the first valve is closed and the water pump continues to work.

[0037] If it is determined that the liquid level in the first water level area reaches the second working water level, the water pump is controlled to shut down;

[0038] If it is determined that the liquid level in the second water level area reaches the preset first minimum water level, the first valve is opened and the water pump is turned on.

[0039] The method in the above scheme further includes:

[0040] When it is determined that the liquid level in the first water level area has reached the first highest water level, the drain valve on the first drain pipe is opened until the liquid level in the first water level area reaches the second working water level.

[0041] When it is determined that the liquid level in the second water level zone has reached the second highest water level, the drain valve on the second drain pipe is opened until the liquid level in the second water level zone reaches the first working water level.

[0042] This invention provides a waste heat recovery system and method for molten steel slag gasification cooling. The system includes: a steel slag crushing zone; a steel slag storage plate placed in the steel slag crushing zone; a heat exchange pipeline laid below the steel slag storage plate; a steam boiler connected to the heat exchange pipeline via a circulation pipeline; and a water pump connected to the steam boiler via a pipeline to provide circulating water to the steam boiler. Thus, during the steel slag roller crushing stage, by laying the heat exchange pipeline below the steel slag crushing zone and providing circulating water to the heat exchange pipeline via the steam boiler, the heat of the steel slag is used to heat the water in the heat exchange pipeline to form pure steam, thereby effectively recovering the waste heat of the steel slag and improving resource utilization. Attached Figure Description

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0044] Figure 1 A schematic diagram of a waste heat recovery system for gasification cooling of molten steel slag according to an embodiment of the present invention is shown.

[0045] Figure 2 Another structural schematic diagram of a waste heat recovery system for gasification cooling of molten steel slag according to an embodiment of the present invention is shown;

[0046] Figure 3 A schematic diagram of a method for recovering waste heat from the gasification and cooling of molten steel slag according to an embodiment of the present invention is shown.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1-Slag crushing equipment; 101-Slag pot transport vehicle; 102-Slag pot lifting equipment; 103-Transfer machine; 104-Slag pre-storage belt; 105-Slag cooling belt; 2-Slag storage plate; 21-Heat exchange furnace; 22-Gas supply equipment; 23-Waste heat boiler; 24-Heat pipe heat exchanger; 25-Plate heat exchanger; 26-Loading funnel; 27-First dust removal equipment; 28-Circulating fan; 29-Second dust removal equipment; 3-Heat exchange pipeline; 30-Slag collection equipment 31-Second deaerator, 32-Slag discharge equipment, 33-Environmental dust removal equipment, 4-Steam drum, 41-First water level zone, 42-Second water level zone, 43-Water baffle, 5-Water pump, 6-Steel slag, 71-First pipeline, 72-Second pipeline, 8-First deaerator, 91-First drain pipe, 92-Second drain pipe, 10-Slag outlet, Vd-First valve, Vr-Second valve, Vs1-First drain valve, Vs2-Second drain valve, D HL -First highest water level, DWL -Second working water level, R LL -First lowest water level, R HL -Second highest water level, R WL -First working water level, D LL -Second lowest water level. Detailed Implementation

[0049] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0050] This invention provides a waste heat recovery system for the gasification and cooling of molten steel slag, such as... Figure 1 As shown, the system includes: 1. steel slag crushing equipment, 2. steel slag storage plate, 3. heat exchange pipeline, 4. steam boiler, and 5. water pump; among which,

[0051] Steel slag storage plate 2 is placed below steel slag crushing equipment 1;

[0052] Heat exchange pipe 3 is laid below steel slag storage plate 2;

[0053] Steam package 4 is connected to heat exchange pipe 3 via a circulation pipe;

[0054] Water pump 5 is connected to steam package 4 via a pipe to provide circulating water to steam package 4.

[0055] Specifically, since steel slag 6 is transported to steel slag storage plate 2 via slag hopper, in order to prevent steel slag from caking and to ensure more thorough heat exchange, steel slag crushing equipment 1 is placed on steel slag storage plate 2 for crushing and spreading the steel slag.

[0056] refer to Figure 1 The circulation pipeline includes: a first pipeline 71 and a second pipeline 72; the steam package 4 includes:

[0057] The first water level zone 41 is connected to one end of the first pipeline 71;

[0058] The second water level zone 42 is connected to one end of the second pipeline 72;

[0059] Water-blocking plate 43 is located between the first water level zone 41 and the second water level zone 42; wherein,

[0060] The water level in the second water level zone 42 is lower than the water level in the first water level zone 41.

[0061] The heat exchange pipe 3 includes: an upper water collection pipe and a lower water collection pipe; wherein,

[0062] The upper water collection pipe is connected to the other end of the second pipe 72;

[0063] The lower water collection pipe is connected to the other end of the first pipe 71.

[0064] In this configuration, the heat exchange pipeline is equivalent to two layers of closely spaced pipes. The lower water collection pipe is connected to the upper water collection pipe via the first pipe 71, the steam drum 4, and the second pipe 72. A steel slag storage plate 2 is laid on the heat exchange pipeline 3, and the steel slag is poured onto the steel slag storage plate 2 to exchange heat with the heat exchange pipeline 3. The steel slag storage plate 2 can be a cast iron plate.

[0065] To ensure that the water in heat exchange pipe 3 can circulate and continuously exchange heat, refer to Figure 1 The system also includes: a first deaerator 8, a first drain pipe 91, and a second drain pipe 92;

[0066] One end of the first deaerator 8 is connected to the first water level zone 41 via the third pipe 81;

[0067] The other end of the first deaerator 8 is connected to the second water level zone 42 via the fourth pipe 82.

[0068] One end of the first drainage pipe 91 is connected to the first water level area 41, and the other end of the first drainage pipe 91 is connected to the third pipe 81.

[0069] One end of the second drainage pipe 92 is connected to the second water level area 42, and the other end of the second drainage pipe 92 is connected to the third pipe 81.

[0070] The first pipe 71 is equipped with a first valve Vd, the second pipe 72 is equipped with a second valve Vr, the first drain pipe 91 is equipped with a first drain valve Vs1, and the second drain pipe 92 is equipped with a second drain valve Vs2.

[0071] When using the above system for preheating recovery, the specific implementation is as follows:

[0072] Before the system starts, the first valve Vd and the second valve Vr are opened, and the demineralized water in the first deaerator 8 is pumped into the first water level zone 41 of the steam boiler 4 by the water pump 5. The demineralized water in the first water level zone 41 will sequentially enter the second water level zone 42 through the lower water collection pipe 52, the first pipe 71, the upper water collection pipe 51, and the second pipe 72. When the water level in the second water level zone 42 reaches the first working water level R... WL At this time, the first valve Vd is closed, while the valve Vr remains open. At this time, the water replenishment in the first water level zone 41 ends, and the water pump 5 continues to work.

[0073] When the water level in the first water level zone 41 reaches the second working water level D WL When pump 5 stops working, the entire system completes its water replenishment process. During the heat exchange process, when the water level in the second water level zone 42 reaches the first minimum water level R... LL At that time, control the first valve Vd to open and start the water pump 5 to continue repeating the above water replenishment work.

[0074] Furthermore, in order to ensure the liquid level difference between the first water level area 41 and the second water level area 42, so that the water can circulate smoothly and the heat exchange operation can proceed smoothly, this embodiment provides drain pipes and drain valves respectively in the first water level area 41 and the second water level area 42.

[0075] Then, when the water level in the first water level zone 41 reaches the first highest water level D... HL At that time, the first drain valve Vs1 is opened to drain water until the first water level zone 41 reaches the second working water level D. WL At that time, the first drain valve Vs1 is closed. The first water level zone 41 also includes a second minimum water level D. LL .

[0076] Similarly, when the water level in the second water level zone 42 reaches the second highest water level R HL At that time, the second drain valve Vs1 is opened to drain water until the water level in the second water level zone 42 reaches the first working water level R. WL Close the second drain valve Vs1.

[0077] By performing the above operations, after starting the system, the first valve Vd can be opened during the heat exchange process to ensure that the water forms a natural circulation.

[0078] The steel slag to be processed is poured from the slag hopper onto the steel slag storage plate. The heat of the steel slag is used to heat the water in the heat exchange pipeline and generate steam, which enters the steam boiler 4.

[0079] When the steam pressure inside steam chamber 4 is determined to be greater than the pressure threshold, the steam valve VS on steam chamber 4 is opened to send steam into the steam pipeline network.

[0080] The preset pressure threshold can be 1.2 MPa. As heat exchange proceeds, steam is continuously generated. When the steam pressure inside the steam drum 4 is greater than 1.2 MPa, the steam valve Vs on the steam drum is opened to deliver steam to the pipeline network; when the pressure inside the steam drum is lower than 1.2 MPa, the steam valve Vs is closed to maintain the pressure of the steam drum 4.

[0081] When the temperature of the steel slag drops to 1100℃, start the steel slag crushing equipment and push the steel slag to the slag outlet 10 for collection. The probability of the collected steel slag particles with a size ≤20mm is greater than 80%, and the maximum size of the steel slag particles is <300mm.

[0082] To match the converter smelting cycle, the processing cycle for each ladle of steel slag is 35 minutes.

[0083] In this embodiment, the heat of the steel slag during the roller crushing stage is converted into water vapor, realizing the effective recovery of the waste heat of the high-temperature steel slag, and crushing the steel slag into small pieces for subsequent processing.

[0084] Based on the same inventive concept as the foregoing embodiments, this embodiment also provides a method for recovering waste heat from the gasification and cooling of molten steel slag, applied to the system described in the above embodiments. The specific structure of the system can be found in [reference needed]. Figure 1 This will not be elaborated upon here. Figure 2 As shown, the method includes the following steps:

[0085] S210, using a water pump to pump demineralized water into the steam package, controlling the opening of the first valve on the second pipeline to form a water circulation;

[0086] In one embodiment, before pumping demineralized water into the steam chamber using a water pump and opening the first valve on the second pipeline to form a water circulation, the method further includes:

[0087] Control the opening of the first valve on the second pipeline and the second valve on the first pipeline;

[0088] Demineralized water is pumped into the first water level zone of the steam package using a water pump, and the demineralized water in the first water level zone is transported to the second water level zone using the siphon principle.

[0089] When the liquid level in the second water level zone is determined to reach the first working water level, the first valve is closed and the water pump continues to work.

[0090] If the liquid level in the first water level zone is determined to reach the second working water level, the water pump will be shut off.

[0091] If the liquid level in the second water level zone is determined to reach the preset first minimum water level, the first valve is opened and the water pump is started simultaneously.

[0092] In this way, after the system is pre-filled with water, demineralized water can be pumped into the steam tank during the heat exchange process, and the first valve Vd can be opened to ensure that the water forms a natural circulation.

[0093] To ensure the liquid level difference between the first and second water level zones, allowing for smooth water circulation and thus ensuring successful heat exchange, the method also includes:

[0094] When the liquid level in the first water level zone is determined to reach the first highest water level, the drain valve on the first drain pipe is opened until the liquid level in the first water level zone reaches the second working water level.

[0095] When the liquid level in the second water level zone reaches the second highest water level, the drain valve on the second drain pipe is opened until the liquid level in the second water level zone reaches the first working water level.

[0096] S211, the steel slag to be processed is poured from the slag pot onto the steel slag storage plate, and the heat of the steel slag is used to heat the water in the heat exchange pipeline and generate steam that enters the steam boiler.

[0097] Then, a can of steel slag to be processed is poured from the slag can onto the steel slag storage plate. At this time, the steel slag exchanges heat with the heat exchange tubes, and the water in the heat exchange tubes is heated to generate steam, which enters the steam drum. To prevent the steel slag from caking at the contact surface, the steel slag is crushed using steel slag crushing equipment and spread evenly on the steel slag storage plate to promote heat exchange.

[0098] The temperature of the steel slag coming out of the slag pot is about 1500℃ (1200~1500℃). The steel slag can be the sticky slag after splashing or the thin slag before splashing.

[0099] S212, when it is determined that the steam pressure in the steam package is greater than the pressure threshold, the steam valve on the steam package is opened to send the steam into the steam pipeline network.

[0100] As heat exchange continues, the water in the steam chamber is converted into steam. When the steam pressure in the steam chamber is determined to be greater than the pressure threshold, the steam valve on the steam chamber is opened to send steam into the steam pipeline network.

[0101] The preset pressure threshold can be 1.2 MPa. As heat exchange proceeds, steam is continuously generated. When the steam pressure inside the steam drum 4 is greater than 1.2 MPa, the steam valve Vs on the steam drum is opened to deliver steam to the pipeline network; when the pressure inside the steam drum is lower than 1.2 MPa, the steam valve Vs is closed to maintain the pressure of the steam drum 4.

[0102] When the temperature of the steel slag drops to 1100℃, start the steel slag crushing equipment and push the steel slag to the slag outlet 10 for collection. The probability of the collected steel slag particles with a size ≤20mm is greater than 80%, and the maximum size of the steel slag particles is <300mm.

[0103] To match the converter smelting cycle, the processing cycle for each ladle of steel slag is 35 minutes.

[0104] It is worth noting that during the roller crushing stage, the recovered steam is saturated low-pressure steam with a pressure of 1.2 MPa and a temperature of 190°C.

[0105] In practical applications, when the waste heat recovery system for molten steel slag gasification cooling provided in the above embodiments is used to recover the waste heat from the gasification cooling of steel slag during the roller crushing stage, the recovery results are shown in Table 1:

[0106] Table 1

[0107]

[0108] As shown in Table 1, during the roller crushing stage, with a thermal efficiency of 70% for the recovery system, the heat recovery efficiency of each batch of steel slag can reach approximately 60%. Here, the heat recovery efficiency is the ratio of the recovered heat of the steel slag to the initial heat of the steel slag, and the recovered heat of the steel slag is the product of the thermal efficiency of the recovery system and the initial heat of the steel slag.

[0109] Since the treated steel slag is around 1100℃, there is still significant potential for waste heat recovery. To further improve the efficiency of waste heat recovery, this embodiment can continue to recover latent heat from the treated steel slag. This stage can be referred to as the latent heat recovery stage of the steel slag. (Reference) Figure 3 The system also includes:

[0110] Slag hopper transport equipment, heat exchange furnace 21, gas supply equipment 22, waste heat boiler 23, heat pipe heat exchanger 24, plate heat exchanger 25; among which,

[0111] The slag pot transport equipment is used to transport slag pots containing steel slag at about 1100℃ to the top of the heat exchange furnace 21 and load the steel slag into the heat exchange furnace 21.

[0112] The first outlet of the heat exchanger 21 is connected to the first inlet of the waste heat boiler 23, and the first inlet of the heat exchanger 21 is connected to the gas supply equipment 22.

[0113] The first outlet of the waste heat boiler 23 is connected to the heat pipe heat exchanger 24;

[0114] One end of the heat pipe heat exchanger 24 is connected to the second inlet of the heat exchange furnace 21, and the heat pipe heat exchanger 24 also needs to be connected to the plate heat exchanger 25.

[0115] Plate heat exchanger 25 is connected to the demineralized water pipeline.

[0116] Specifically, please refer to Figure 2 The slag tank transportation equipment includes: a slag tank transport vehicle 101, a slag tank lifting device 102, and a translating machine 103; among which,

[0117] The slag tanker truck 101 is used to transport slag tanks to the area below the slag tanker lifting equipment 102;

[0118] The slag pot lifting device 102 is used to lift the slag pot to the translation machine 103;

[0119] The translation machine 103 is used to move the slag pot horizontally above the heat exchange furnace 21.

[0120] A loading funnel 26 is also provided above the heat exchange furnace 21, through which steel slag flows into the heat exchange furnace 21. The temperature of the steel slag flowing into the heat exchange furnace 21 is about 1100℃. The loading funnel 26 is equipped with a rotary sealing valve, which allows the steel slag to fall into the heat exchange furnace 21 when the sealing valve is opened.

[0121] Then the translation machine 103 moves the empty slag pot to the slag pot lifting device 102. The slag pot lifting device 102 descends and places the empty slag pot on the slag pot transport vehicle 101. The slag pot transport vehicle 101 transports the empty slag pot to the steel slag roller crushing area to continue receiving slag.

[0122] Continue to refer to Figure 1 The heat exchanger 21 includes: a slag pre-storage zone 104 and a cooling zone 105.

[0123] The steel slag pre-storage belt 104 is located above the heat exchange furnace 21 and is used for pre-storing steel slag;

[0124] The cooling zone 105, located below the slag pre-storage zone 104, is used to cool the slag using gas supplied by the gas supply device 22. The gas supply device 22 can provide nitrogen, CO2, or other inert gases.

[0125] In the steel slag cooling zone 105, gas supply device 22 blows gas, such as nitrogen, into the heat exchange furnace 21 from the bottom. The ratio of nitrogen flow rate to steel slag throughput (gas-to-solid ratio of 860 Nm³) is used. 3 / t), so that the steel slag and nitrogen can be in full contact in the heat exchange furnace 21, and the high temperature gas is discharged from the upper part of the cooling zone, that is, the heat exchange furnace 21 can output high temperature gas of about 800℃.

[0126] refer to Figure 1 The system also includes: a first dust removal device 27, a circulating fan 28, a second dust removal device 29, a slag collection device 30, and a second deaerator 31;

[0127] The first dust removal device 27 is installed between the first outlet of the heat exchanger 21 and the first inlet of the waste heat boiler 23.

[0128] The circulating fan 28 and the second dust removal device 29 are installed sequentially between the heat pipe heat exchanger 24 and the first outlet of the waste heat boiler 23.

[0129] The slag collection device 30 is connected to the outlets of the first dust removal device 27 and the second dust removal device 29, respectively.

[0130] Plate heat exchanger 25 is connected to heat pipe heat exchanger 24;

[0131] The inlet of the second deaerator 31 is connected to the outlet of the plate heat exchanger 25, and the outlet of the second deaerator 31 is connected to the second inlet of the waste heat boiler 23.

[0132] Specifically, the first dust removal device 27 is used to remove dust from the high-temperature gas coming out of the heat exchange furnace 21. The high-temperature gas after the first dust removal enters the waste heat boiler 23 to produce medium-pressure steam. The medium-pressure steam can be connected to the steam pipeline network or used for power generation.

[0133] After exchanging heat with the waste heat boiler 23, the temperature of the high-temperature gas drops to 170℃~190℃. After secondary dust removal by the second dust removal device 29, the gas enters the heat pipe heat exchanger 24 installed on the feed water pipeline of the waste heat boiler 23 under the guidance of the circulating fan 28, which heats the water in the heat pipe heat exchanger 24. After the gas comes out of the heat pipe heat exchanger 24, the temperature drops to about 130℃, and it enters the heat exchange furnace 21 again from the bottom of the furnace for circulation.

[0134] Hot water from heat pipe heat exchanger 24 enters plate heat exchanger 25 to preheat demineralized water. To prevent the preheated demineralized water from corroding the waste heat boiler, the preheated demineralized water from plate heat exchanger 25 also needs to enter a second deaerator 31 for deoxygenation, and then is pumped by boiler water pump into waste heat boiler 23 for the production of medium-pressure steam. The demineralized water is obtained by purifying industrial wastewater discharged from other production lines in the plant.

[0135] Further reference Figure 1 The system also includes:

[0136] The slag discharge device 32 is connected to the second outlet of the heat exchange furnace 21. The cooled steel slag (about 100°C) is discharged through the slag discharge device 32 and enters the steel slag secondary processing production line for processing.

[0137] In addition, to avoid dust pollution in the workshop, the system also includes: an environmental dust removal device 33, which is connected to the first outlet of the heat exchange furnace 21, the second outlet of the heat exchange furnace 21, and the loading funnel 26, respectively.

[0138] During the latent heat recovery stage of steel slag, medium-pressure steam at 3.9 MPa and 450℃ can be recovered.

[0139] As can be seen, the steel slag treatment process in this embodiment is a dry process, and all heat exchange equipment is non-contact heat exchange, so the produced water vapor does not contain dust. The recovery system in this embodiment has a simple structure and is easy to industrialize. By recovering the latent heat of steel slag, 55% of the latent heat of steel slag can be recovered at this stage, reducing CO2 emissions by 55.77 kg per ton of slag, further promoting the green and low-carbon development of steel enterprises.

[0140] It is worth noting that the cooling heat recovery and steel slag latent heat recovery methods in the roller crushing stage of this embodiment can be used separately or in combination. When used in combination, the specific data can be seen in Table 2. The thermal efficiency of steel slag latent heat recovery can reach about 80%, which largely avoids resource waste.

[0141] Table 2

[0142]

[0143] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0144] This invention provides a system and method for recovering waste heat from the gasification and cooling of molten steel slag. The system includes: a steel slag crushing zone; a steel slag storage plate placed in the steel slag crushing zone; a heat exchange pipeline laid below the steel slag storage plate; a steam boiler connected to the heat exchange pipeline via a circulation pipeline; and a water pump connected to the steam boiler via a pipeline to provide circulating water to the steam boiler. Thus, during the steel slag roller crushing stage, by laying the heat exchange pipeline below the steel slag crushing zone and providing circulating water to the heat exchange pipeline via the steam boiler, the heat from the steel slag is used to heat the water in the heat exchange pipeline to form pure steam, thereby effectively recovering the waste heat from the steel slag and improving resource utilization.

[0145] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0146] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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 present invention.

Claims

1. A waste heat recovery system for molten steel slag gasification cooling, characterized in that, The system includes: Steel slag crushing equipment; A steel slag storage plate is placed below the steel slag crushing equipment; Heat exchange pipes are laid beneath the steel slag storage plate; The steam package is connected to the heat exchange pipeline via a circulation pipeline; A water pump, connected to the steam generator via a pipeline, provides circulating water to the steam generator; The steel slag crushing equipment is placed on the steel slag storage plate for crushing and spreading the steel slag. The circulation pipeline includes: a first pipeline and a second pipeline; the steam package includes: The first water level area is connected to one end of the first pipeline; The second water level area is connected to one end of the second pipeline; A baffle plate is located between the first water level area and the second water level area; wherein, The water level in the second water level area is lower than the water level in the first water level area; The heat exchange pipeline includes: an upper water collection pipeline and a lower water collection pipeline; wherein... The upper water collection pipe is connected to the other end of the second pipe; The lower water collection pipe is connected to the other end of the first pipe; The system also includes: a first deaerator; One end of the first deaerator is connected to the first water level zone via a third pipe; The other end of the first deaerator is connected to the second water level zone via a fourth pipe.

2. The system as described in claim 1, characterized in that, The system also includes: The first drain pipe has one end connected to the first water level area and the other end connected to the third pipe. The second drain pipe has one end connected to the second water level area and the other end connected to the third pipe.

3. The system as described in claim 1, characterized in that, The system also includes a slag outlet, located at one end of the steel slag crushing equipment.

4. A method for recovering waste heat from the gasification and cooling of molten steel slag, characterized in that, When applied in the system according to any one of claims 1 to 3, the method comprises: Demineralized water is pumped into the steam package using a water pump, and the first valve on the second pipeline is opened to form a water circulation. The steel slag to be processed is poured from the slag hopper onto the steel slag storage plate. The heat of the steel slag is used to heat the water in the heat exchange pipeline and generate steam, which then enters the steam boiler. When the steam pressure inside the steam chamber is determined to be greater than the pressure threshold, the steam valve on the steam chamber is opened to send the steam into the steam pipeline network.

5. The method as described in claim 4, characterized in that, Before the step of pumping demineralized water into the steam chamber using a water pump and controlling the opening of the first valve on the second pipeline to form a water circulation, the method further includes: Control the opening of the first valve on the second pipeline and the second valve on the first pipeline; Demineralized water is pumped into the first water level area of ​​the steam package using a water pump, and the demineralized water in the first water level area is transported to the second water level area using the siphon principle. When it is determined that the liquid level in the second water level zone has reached the first working water level, the first valve is closed and the water pump continues to work. If it is determined that the liquid level in the first water level area reaches the second working water level, the water pump is controlled to shut down; If it is determined that the liquid level in the second water level area reaches the preset first minimum water level, the first valve is opened and the water pump is turned on.

6. The method as described in claim 5, characterized in that, The method further includes: When it is determined that the liquid level in the first water level area has reached the first highest water level, the drain valve on the first drain pipe is opened until the liquid level in the first water level area reaches the second working water level. When it is determined that the liquid level in the second water level zone has reached the second highest water level, the drain valve on the second drain pipe is opened until the liquid level in the second water level zone reaches the first working water level.

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