Kiln cover type high temperature molten slag waste heat recovery system

Abstract

The present application relates to a kind of kiln cover type high-temperature slag waste heat recovery system, it includes tunnel kiln, transport car, heat exchanger, water-cooled wall, air blower, evaporator, superheater, coal economizer, desalted water tank, fresh air fan, deaerating steam drum.Tunnel kiln is divided into slow cooling section, fast cooling section and deep cooling section from first end to end, transport car is used to transport slag ladle, heat exchanger includes heat collection air pipe, heat exchanger carries out heat exchange between slow cooling section and fast cooling section, the size of wind speed in heat collection air pipe can be adjusted, can effectively adjust the temperature drop range of copper slag in slow cooling section.Fast cooling section uses the combination cooling mode of water-cooled wall and air cooling to carry out rapid cooling, substantially reduces the cooling time in traditional process under the premise of realizing heat recovery.Deep cooling section is deeply cooled by fresh air and circulating air, realizes the step utilization of molten slag heat.Reduces the high energy consumption of molten slag processing, improves metal recovery rate, reduces the turnover time of slag ladle.

Description

Technical Field

[0001] The present invention relates to the field of high-temperature slag waste heat recovery, and in particular to a kiln hood type high-temperature slag waste heat recovery system. Background Art

[0002] Non-ferrous metal smelting is an energy-intensive and highly polluting industry, offering significant potential for energy conservation and emission reduction. Copper slag is a key byproduct of the copper smelting process, with high production volume and high waste heat and metal recovery value. In traditional copper slag processing, 1300°C slag is discharged from the furnace into a slag bag. Slag trucks transport the slag bag to a slag bag yard for natural cooling in the open air. Once the slag temperature drops to 300-400°C, water is sprayed into the bag until it is completely cooled. The slag is then subjected to flotation to recover copper and other metals. Finally, the slag is crushed and sold to cement plants as an iron-containing raw material for cement. The cooling time for the slag bag takes a total of 72 hours, and the spraying process consumes a large amount of cooling water. The cooling water heated by the slag needs to be cooled and reused in cooling towers. Currently, the industry is largely unable to recycle the waste heat from the slag, which is a major challenge, but it also represents a potential area for smelting companies to utilize waste heat.

[0003] At the same time, copper slag is rich in copper, iron, inorganic substances and other substances, which can be recovered through flotation and other methods. In order to improve the copper recovery rate, the subsequent flotation process requires that the copper slag needs to be slowly cooled and crystallized in the previous process to further improve the economic benefits.

[0004] The current common copper slag treatment process relies primarily on a combination of natural standing and spray cooling. However, this method fails to recover waste heat, and the slow cooling time and rate are affected by ambient temperature and cannot be controlled, making it difficult to control copper crystallization efficiency and, consequently, copper recovery rates. Furthermore, the extended cooling period during the rapid cooling phase of natural cooling hinders the reusability of the slag bag and increases equipment investment costs. Summary of the Invention

[0005] The purpose of the present invention is to provide a kiln hood type high temperature slag waste heat recovery system to solve the problems of high energy consumption, low metal recovery rate and long slag bag turnover time in traditional slag treatment processes.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] The present invention provides a kiln hood type high temperature slag waste heat recovery system, which includes a tunnel kiln, a conveyor vehicle, a heat exchanger, a water-cooled wall, a blower, an evaporator, a superheater, an economizer, a desalted water tank, a fresh air blower, and a deaerator drum;

[0008] The tunnel kiln is divided into a slow cooling section, a fast cooling section, and a deep cooling section from the head end to the tail end. The conveyor vehicle is used to transport the slag bag and move from the head end to the tail end of the tunnel kiln. The heat exchanger includes a heat collecting air duct, and the wind speed in the heat collecting air duct is adjustable. The heat exchanger exchanges heat between the slow cooling section and the fast cooling section. The water-cooled wall is provided on the inner wall of the fast cooling section.

[0009] The cold air at the blower outlet is blown into the deep cooling section, and the cold air forms medium-temperature air after heat exchange in the deep cooling section and enters the fast cooling section. The medium-temperature air forms medium-high-temperature air after heat exchange in the fast cooling section, and part of it enters the evaporator, and the other part enters the heat collecting air duct. The air at the heat collecting air duct outlet enters the superheater, and the air at the evaporator outlet and the air at the superheater outlet are combined and enter the economizer to preheat the desalted water flowing out of the desalted water tank. The air flowing out of the economizer enters the inlet of the blower to form circulating air, and the fresh air blower is used to blow external cold air into the deep cooling section;

[0010] The desalted water and the steam drain return water in the circulating air duct are mixed and then enter the desalted water tank. The desalted water flowing out of the desalted water tank is transported to the economizer for heating and then sent to the deaeration drum. The hot water from the deaeration drum is respectively transported to the water-cooled wall and the evaporator for heating and then flows back to the deaeration drum to form circulating water.

[0011] In some embodiments of the present application, an isolation door assembly is provided at the entrance of the slow cooling section;

[0012] The isolation door assembly includes a first gate and a second gate located behind the first gate;

[0013] When the first gate is open and the second gate is closed, the transport vehicle moves from the front side of the first gate to between the first gate and the second gate;

[0014] When the first gate is closed and the second gate is opened, the transport vehicle moves from between the first gate and the second gate to the rear side of the second gate.

[0015] In some embodiments of the present application, the heat exchanger is a heat pipe heat exchanger;

[0016] The heat pipe heat exchanger is arranged at the top of the slow cooling section;

[0017] The heat pipe heat exchanger further comprises a plurality of heat pipes, which are arranged at intervals along the conveying direction of the conveying vehicle. The heat absorbing ends of the heat pipes are arranged in the slow cooling section, and the heat releasing ends of the heat pipes are arranged in the heat collecting air duct.

[0018] In some embodiments of the present application, the kiln hood type high temperature slag waste heat recovery system further includes a desalted water pump and a furnace water pump;

[0019] The desalted water flowing out of the desalted water tank is transported to the economizer via the desalted water pump;

[0020] The hot water from the deaeration drum is transported to the water-cooled wall and the evaporator respectively via the boiler water pump.

[0021] In some embodiments of the present application, the kiln hood type high temperature slag waste heat recovery system further includes a heat accumulator;

[0022] When there is excess saturated steam in the deaeration drum, the excess steam enters the superheater and is transported outward or enters the heat accumulator for storage.

[0023] In some embodiments of the present application, the kiln hood type high temperature slag waste heat recovery system further includes an induced draft fan;

[0024] The induced draft fan extracts the medium-temperature air from the outlet of the deep cooling section and blows the medium-temperature air into the fast cooling section.

[0025] In some embodiments of the present application, the kiln hood type high temperature slag waste heat recovery system further includes a stirrer;

[0026] The stirrer is arranged in the slow cooling section, and is used to stir the slag.

[0027] In some embodiments of the present application, the stirrer is provided at the middle and lower parts of both sides of the slow cooling section;

[0028] The stirrer is an electromagnetic stirrer.

[0029] In some embodiments of the present application, emergency ventilation holes are provided on both sides of the slow cooling section;

[0030] A circulating air blowing interface and a circulating air suction interface are arranged at intervals on the top of the quick cooling section and the deep cooling section.

[0031] In some embodiments of the present application, a conveying track is laid in the tunnel kiln;

[0032] The conveying track passes through the slow cooling section, the fast cooling section and the deep cooling section, and the conveying vehicle can move along the conveying track;

[0033] The kiln hood type high-temperature slag waste heat recovery system further includes a scrap metal baler, which is used to transport the slag bags to the conveyor vehicle.

[0034] It can be seen from the above technical solutions that the embodiments of the present invention have at least the following advantages and positive effects:

[0035] In the kiln hood-type high-temperature slag waste heat recovery system of the embodiment of the present invention, according to the characteristics of the slag at different stages, a heat exchanger is used in the slow cooling section to exchange heat between the slow cooling section and the heat collecting air duct, which can exchange heat and cool the slag in the slow cooling section. By adjusting the wind speed in the heat collecting air duct, the cooling range of the slag in the slow cooling section can be effectively adjusted to a pre-designed 1~2°C / min. At the same time, because the circulating air is heat exchanged through the heat collecting air duct of the heat exchanger, it is not directly blown onto the slag surface, eliminating local cooling of the slag, thereby eliminating the impact of local cooling on the crystallization rate, making the slow cooling time and slow cooling rate controllable, and improving the crystallization efficiency and recovery rate. In the fast cooling section, the temperature of the slag is relatively high. In order to ensure efficient use of heat, a combined cooling method of water-cooled wall and air cooling is adopted for rapid cooling. Under the premise of achieving heat recovery, the cooling time in the traditional process is greatly reduced, and a certain amount of water resource waste is reduced. In the deep cooling section, a fresh air fan is installed at the slag bag outlet to compensate for air volume loss during the heat exchange process. The fresh air generated by the fan is combined with circulating air to deeply cool the deep cooling section, achieving a cascaded utilization of slag heat. This reduces energy consumption in slag processing, improves metal recovery, and shortens slag bag turnover time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The various objects, features, and advantages of the present invention will become more apparent upon consideration of the following detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings are merely illustrative illustrations of the present invention and are not necessarily drawn to scale. In the drawings, like reference numerals refer to the same or similar parts throughout.

[0037] Figure 1 It is a structural schematic diagram of a kiln hood type high-temperature slag waste heat recovery system according to an exemplary embodiment.

[0038] Figure 2 yes Figure 1 Elevation drawing of the layout of the slow cooling section.

[0039] Figure 3 yes Figure 1 The layout plan of the slow cooling section. DETAILED DESCRIPTION

[0040] Although the present invention is susceptible of being embodied in different forms, only some of the specific embodiments are shown in the drawings and will be described in detail in this specification. It should be understood that this description should be regarded as an exemplary illustration of the principles of the invention and is not intended to limit the invention to that described herein.

[0041] Thus, a feature indicated in this specification is intended to illustrate one of the features of one embodiment of the present invention, rather than to imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features can be combined together to illustrate possible system designs, these features can also be used in other, not explicitly described, combinations. Thus, unless otherwise noted, the described combinations are not intended to be limiting.

[0042] In the embodiments shown in the accompanying drawings, directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of various components of the present invention are not absolute but relative. These descriptions are applicable when these components are in the positions shown in the accompanying drawings. If the descriptions of the positions of these components are changed, these directional indications will also change accordingly.

[0043] See also Figures 1 to 3 The kiln hood type high temperature slag waste heat recovery system provided by one embodiment of the present invention mainly includes a tunnel kiln, a conveyor vehicle, a heat exchanger, a water-cooled wall, a blower, an evaporator, a superheater, an economizer, a desalted water tank, a fresh air blower, and a deaerator drum.

[0044] The tunnel kiln is divided into a slow cooling section, a fast cooling section and a deep cooling section from the head end to the tail end. The conveyor vehicle is used to transport the slag bag and move it from the head end to the tail end of the tunnel kiln. The heat exchanger includes a heat collecting air duct, and the wind speed in the heat collecting air duct is adjustable. The heat exchanger exchanges heat between the slow cooling section and the fast cooling section, and the water-cooled wall is arranged on the inner wall of the fast cooling section.

[0045] The cold air at the blower outlet is blown into the deep cooling section. After heat exchange in the deep cooling section, the cold air becomes medium-temperature air and enters the fast cooling section. After heat exchange in the fast cooling section, the medium-temperature air becomes medium-high temperature air, part of which enters the evaporator, and the other part enters the heat collecting air duct. The air at the heat collecting air duct outlet enters the superheater. The air at the evaporator outlet and the superheater outlet are combined and enter the economizer to preheat the desalted water flowing out of the desalting water tank. The air flowing out of the economizer enters the inlet of the blower to form circulating air. The fresh air fan is used to blow external cold air into the deep cooling section.

[0046] The desalted water and the steam drain return water in the circulating air duct are mixed and then enter the desalted water tank. The desalted water flowing out of the desalted water tank is transported to the economizer for heating and then sent to the deaerator drum. The hot water from the deaerator drum is transported to the water-cooled wall and evaporator for heating and then flows back to the deaerator drum to form circulating water.

[0047] Through the above design, in response to the characteristics of the slag at different stages, a heat exchanger is used in the slow cooling section to exchange heat between the slow cooling section and the heat collecting air duct, which can exchange heat and cool the slag in the slow cooling section. By adjusting the wind speed in the heat collecting air duct, the slag cooling range in the slow cooling section can be effectively adjusted to a pre-designed 1-2°C / min. At the same time, because the circulating air exchanges heat through the heat collecting air duct of the heat exchanger, it does not directly blow onto the slag surface, eliminating local cooling of the slag and thus eliminating the impact of local cooling on the crystallization rate. This makes the slow cooling time and slow cooling rate controllable, improving the crystallization efficiency and recovery rate. In the rapid cooling section, the slag temperature is relatively high. To ensure efficient heat utilization, a combined cooling method of water-cooled walls and air cooling is used for rapid cooling. While achieving heat recovery, this significantly reduces the cooling time in traditional processes and reduces a certain amount of water waste. In the deep cooling section, a fresh air fan is installed at the slag bag outlet to compensate for air volume loss during the heat exchange process. The fresh air generated by the fan is combined with circulating air to deeply cool the deep cooling section, achieving a cascaded utilization of slag heat. This reduces energy consumption in slag processing, improves metal recovery, and shortens slag bag turnover time.

[0048] The three production sections, slow cooling section, fast cooling section and deep cooling section, can be divided according to the temperature of the slag in the slag ladle and the actual temperature of the production section.

[0049] A conveyor track is laid inside the tunnel kiln. It passes through the slow cooling section, the rapid cooling section, and the deep cooling section, and is used by a transport vehicle. The kiln hood-type high-temperature slag waste heat recovery system also includes a scrap metal baler, which transfers the slag bags to the transport vehicle. The three production zones are connected by a conveyor track, which defines the transport vehicle's trajectory and facilitates smooth movement. The transport vehicle travels along the track through each production zone sequentially within the insulated and enclosed tunnel kiln.

[0050] It is worth mentioning that multiple conveyor vehicles can be connected to the conveyor track. At the same time, one or more conveyor vehicles can be set up in each production area of ​​the slow cooling section, fast cooling section and deep cooling section respectively. The number of conveyor vehicles can be flexibly set according to the heat exchange time of each production area to ensure the optimal number of slag bags in each heat exchange area and to ensure that each heat exchange area can work continuously.

[0051] The entrance to the slow cooling section is provided with an isolation door assembly. The isolation door assembly includes a first gate and a second gate located behind the first gate. When the first gate is open and the second gate is closed, the transport vehicle moves from the front side of the first gate to between the first gate and the second gate. When the first gate is closed and the second gate is opened, the transport vehicle moves from between the first gate and the second gate to the rear side of the second gate. During continuous operation, when slag bags need to be fed into the tunnel kiln, the first gate is first opened and the second gate is closed, and the transport vehicle transports the slag bags to between the first gate and the second gate. The second gate prevents heat leakage from the tunnel kiln. Then the first gate is closed and the second gate is opened, and the transport vehicle transports the slag bags to the rear side of the second gate into the tunnel kiln. The first gate prevents heat leakage from the tunnel kiln. This can reduce large temperature fluctuations when the gates are open, thereby ensuring the continuity of heat supply.

[0052] Emergency ventilation holes are installed on both sides of the slow cooling section. By monitoring the internal temperature of the slow cooling section, when the temperature inside the slow cooling section is too high, an appropriate amount of low-temperature air can be introduced through the emergency ventilation holes to neutralize it, ensuring that the slow cooling area will not overheat and the structural safety is guaranteed.

[0053] The heat exchanger is a heat pipe heat exchanger, which is arranged at the top of the slow cooling section. The heat pipe heat exchanger also includes a plurality of heat pipes, which are arranged at intervals along the conveying direction of the conveying vehicle. The heat absorbing end of the heat pipe is arranged in the slow cooling section, and the heat releasing end of the heat pipe is arranged in the heat collecting air duct. By utilizing the high thermal conductivity of the heat pipe, effective heat exchange between the slow cooling section and the heat collecting air duct can be achieved. At the same time, by utilizing the isothermal property of the heat pipe, that is, the temperature of the heat releasing end and the heat absorbing end of the heat pipe is equal, the temperature of the heat releasing end in the heat collecting air duct can be measured by an infrared thermometer, thereby obtaining the temperature characteristics of the copper slag in each section of the slow cooling section. The heat pipe heat exchanger can be based on actual site requirements, such as Figure 3 The arrangement is symmetrical as shown in FIG, and a one-sided arrangement is also possible.

[0054] In the initial stage of slow cooling, the temperature of the slag bag in the slow cooling zone can be adjusted to dissipate heat at a rate of 1-2°C / min by adjusting the wind speed of the heat collecting air duct installed on the heat pipe heat exchanger. The hot air coming out of the heat collecting air duct is led to the fast cooling section through the air duct.

[0055] The kiln hood-type high-temperature slag waste heat recovery system also includes an agitator, located in the slow cooling section, for stirring the slag. Depending on the slag ladle's operating speed, the agitator can generate a rotational speed of 3 to 6 r / min for the slag within the ladle. This slow rotation promotes the aggregation and growth of copper mineral particles within the ladle, improving the crystallization efficiency of copper particles and other materials, facilitating subsequent flotation recovery of copper, thereby increasing the copper recovery rate. Furthermore, even after the copper slag surface initially solidifies to form a solid slag crust, the molten slag at the center of the copper slag can be continuously stirred, improving the overall copper recovery efficiency within the entire slag ladle and overcoming the adverse effects of a slag crust forming on the surface of the molten copper slag.

[0056] In this embodiment, stirrers are provided at the middle and lower parts of both sides of the slow cooling section to improve stirring uniformity and ensure stirring effect.

[0057] In this embodiment, the stirrer is an electromagnetic stirrer, comprised of electromagnetic coils. This stirrer maintains a constant rotational speed within the slag ladle, preventing surface slag from affecting the stirring process and preventing the sticking problem common with mechanical stirring. By controlling the voltage and current of the battery stirrer, the rotational speed of the electromagnetic stirrer can be controlled, ensuring that low-speed stirring promotes copper crystallization.

[0058] Circulating air blowing interfaces and circulating air suction interfaces are arranged at intervals on the top of the quick cooling section and the deep cooling section. The circulating air blowing interfaces and circulating air suction interfaces are arranged at intervals and in a staggered manner to ensure that the quick cooling section and the deep cooling section can be cooled evenly.

[0059] In this embodiment, water-cooled walls are provided on two opposite inner walls of the rapid cooling section to further enhance the heat exchange effect.

[0060] The circulating air flow path is described in detail with reference to the above embodiment: The air in the system is circulated throughout the heat exchange system as a cooling medium through blowers and induced draft fans, heating and cooling the system. When the system reaches a stable state, cold air at approximately 90°C is blown from the blower outlet into the cryogenic section. At the cryogenic section outlet, the induced draft fan accelerates the extraction of medium-temperature air at 100-150°C, which has undergone heat exchange within the cryogenic section. This medium-temperature air is then pumped into the rapid cooling section. After being heated by the high-temperature slag, the hot air exiting the rapid cooling section reaches 250°C. Simultaneously, in the rapid cooling section, while absorbing heat from the high-temperature slag, the hot air also sweeps across the water-cooled walls on either side of the rapid cooling section, further enhancing the heat exchange effect. The approximately 250°C hot air exiting the rapid cooling section passes through a regulating valve, where a portion enters the evaporator to heat the circulating water within the evaporator. The remaining portion enters the heat pipe heat collector duct in the slow cooling section, where it is further heated to approximately 350°C. This hot air then enters the superheater, further heating the steam passing through the superheater and improving steam quality. The circulating air at the superheater outlet is cooled to about 200℃, and after merging with the circulating air at 150~180℃ at the evaporator outlet, they enter the economizer together to preheat the desalted water. The circulating air coming out of the economizer is cooled to about 90℃, and then re-injected into the deep cooling section through the blower to cool the deep cooling section slag at the tunnel kiln outlet, thereby increasing the circulating air temperature. In order to compensate for the loss of circulating air in the process, a fresh air blower is set in the deep cooling section at the tunnel kiln outlet to supplement the lost circulating air. After the circulating air and fresh air are mixed, they are circulated and exchanged with the slag in the tunnel kiln in the deep cooling section.

[0061] Circulating water flow: Demineralized water is mixed with steam drain return water in the pipeline to approximately 70°C, then enters the demineralized water tank and is pumped to the economizer via a demineralized water pump, where it is heated to approximately 100°C before being sent to the deaerator drum. Hot water from the deaerator drum is pumped to the water-cooled wall and evaporator via a boiler water pump, where it is heated using the circulating air at different temperatures before returning to the deaerator drum. The water-cooled wall and evaporator absorb heat from their respective waste heat systems to generate a continuous supply of steam. Saturated steam at 180°C is transported from the drum. When steam production is excessive, some of the excess steam enters the superheater, where it is heated to approximately 250°C to further improve steam quality before being transported to the drum or stored in a heat accumulator.

[0062] It should be noted that the cold, medium temperature, medium-high temperature and high temperature in the present invention are referred to by comparing the high and low temperatures, and are not intended to limit the temperature to a certain range. For example, the temperatures of cold, medium temperature, medium-high temperature and high temperature increase in sequence.

[0063] Slag Bag Flow: The slag bag containing high-temperature molten slag is loaded onto a conveyor vehicle via a dedicated vehicle. The conveyor vehicle then travels along a continuous track into the tunnel kiln. Inside the tunnel kiln, the slag is divided into three production zones: slow cooling, rapid cooling, and deep cooling, depending on the temperature of the copper slag. The conveyor vehicle passes through these three zones in sequence. For example, using copper slag as an example, a multi-stage, high-efficiency heat exchange system consisting of an economizer, deaerator drum, water-cooled wall, steam generator, and superheater progressively reduces the processing time of each of the three zones: slow cooling, rapid cooling, and deep cooling. This reduces the processing time of copper slag from the traditional 72 hours to approximately 24 hours, significantly improving the slag bag turnover efficiency. The controlled cooling time in the slow cooling zone is 2-3 hours, the rapid cooling zone is 10-15 hours, and the deep cooling zone is approximately 3-5 hours. The kiln hood-type high-temperature molten slag waste heat recovery system can also be used for similar projects in other smelting industries, such as, but not limited to, the large quantities of slag (blast furnace slag and steel slag) generated by the steel and metallurgical industry. The kiln hood type high temperature slag waste heat recovery system is suitable for the continuous operation process of recovering high temperature slag waste heat and improving the recovery rate.

[0064] It should be noted that multiple kiln hood-type high-temperature slag waste heat recovery systems can be arranged in the plant to form a production line to increase the slag recovery capacity.

[0065] While the present invention has been described with reference to several exemplary embodiments, it should be understood that the terms used are intended to be illustrative and exemplary rather than restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope of the appended claims. All changes and modifications that fall within the scope of the claims or their equivalents are intended to be covered by the appended claims.

Claims

1. A kiln hood type high temperature slag waste heat recovery system, characterized in that: Including tunnel kiln, conveyor car, heat exchanger, water-cooled wall, blower, evaporator, superheater, economizer, desalted water tank, fresh air blower, deaerator drum; The tunnel kiln is divided into a slow cooling section, a fast cooling section, and a deep cooling section from the head end to the tail end. The conveyor vehicle is used to transport the slag bag and move from the head end to the tail end of the tunnel kiln. The heat exchanger includes a heat collecting air duct, and the wind speed in the heat collecting air duct is adjustable. The heat exchanger exchanges heat between the slow cooling section and the fast cooling section. The water-cooled wall is provided on the inner wall of the fast cooling section. The cold air at the blower outlet is blown into the deep cooling section, and the cold air forms medium-temperature air after heat exchange in the deep cooling section and enters the fast cooling section. The medium-temperature air forms medium-high-temperature air after heat exchange in the fast cooling section, and part of it enters the evaporator, and the other part enters the heat collecting air duct. The air at the heat collecting air duct outlet enters the superheater, and the air at the evaporator outlet and the air at the superheater outlet are combined and enter the economizer to preheat the desalted water flowing out of the desalted water tank. The air flowing out of the economizer enters the inlet of the blower to form circulating air, and the fresh air blower is used to blow external cold air into the deep cooling section; The desalted water and the steam drain return water in the circulating air duct are mixed and then enter the desalted water tank. The desalted water flowing out of the desalted water tank is transported to the economizer for heating and then sent to the deaeration drum. The hot water from the deaeration drum is respectively transported to the water-cooled wall and the evaporator for heating and then flows back to the deaeration drum to form circulating water.

2. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: The entrance of the slow cooling section is provided with an isolation door assembly; The isolation door assembly includes a first gate and a second gate located behind the first gate; When the first gate is open and the second gate is closed, the transport vehicle moves from the front side of the first gate to between the first gate and the second gate; When the first gate is closed and the second gate is opened, the transport vehicle moves from between the first gate and the second gate to the rear side of the second gate.

3. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: The heat exchanger is a heat pipe heat exchanger; The heat pipe heat exchanger is arranged at the top of the slow cooling section; The heat pipe heat exchanger further comprises a plurality of heat pipes, which are arranged at intervals along the conveying direction of the conveying vehicle. The heat absorbing ends of the heat pipes are arranged in the slow cooling section, and the heat releasing ends of the heat pipes are arranged in the heat collecting air duct.

4. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: The kiln hood type high temperature slag waste heat recovery system also includes a desalted water pump and a furnace water pump; The desalted water flowing out of the desalted water tank is transported to the economizer via the desalted water pump; The hot water from the deaeration drum is transported to the water-cooled wall and the evaporator respectively via the boiler water pump.

5. The kiln hood type high temperature slag waste heat recovery system according to claim 4, characterized in that: The kiln hood type high temperature slag waste heat recovery system also includes a heat accumulator; When there is excess saturated steam in the deaeration drum, the excess steam enters the superheater and is transported outward or enters the heat accumulator for storage.

6. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: The kiln hood type high temperature slag waste heat recovery system also includes an induced draft fan; The induced draft fan extracts the medium-temperature air from the outlet of the deep cooling section and blows the medium-temperature air into the fast cooling section.

7. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: The kiln hood type high temperature slag waste heat recovery system also includes a stirrer; The stirrer is arranged in the slow cooling section, and is used to stir the slag.

8. The kiln hood type high temperature slag waste heat recovery system according to claim 7, characterized in that: The stirrer is provided at the middle and lower parts of both sides of the slow cooling section; The stirrer is an electromagnetic stirrer.

9. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: Emergency ventilation holes are provided on both sides of the slow cooling section; A circulating air blowing interface and a circulating air suction interface are arranged at intervals on the top of the quick cooling section and the deep cooling section.

10. The kiln hood type high temperature slag waste heat recovery system according to claim 1, characterized in that: A conveying track is laid in the tunnel kiln; The conveying track passes through the slow cooling section, the fast cooling section and the deep cooling section, and the conveying vehicle can move along the conveying track; The kiln hood type high-temperature slag waste heat recovery system further includes a scrap metal baler, which is used to transport the slag bags to the conveyor vehicle.

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