Kiln cover type high-temperature slag waste heat recovery system

Abstract

The invention relates to a kiln cover type high-temperature slag waste heat recovery system which comprises a tunnel kiln, a conveying vehicle, a heat exchanger, a water cooling wall, an air blower, an evaporator, a superheater, an economizer, a desalting water tank, a fresh air fan and a deoxidizing steam pocket. The tunnel kiln is sequentially divided into a slow cooling section, a rapid cooling section and a deep cooling section from the head end to the tail end, the conveying vehicle is used for conveying cinder ladles, the heat exchanger comprises a heat collection air duct and exchanges heat between the slow cooling section and the heat collection air duct, the air speed in the heat collection air duct can be adjusted, and the cooling amplitude of copper slag in the slow cooling section can be effectively adjusted. And the rapid cooling section adopts a combined cooling mode of a water cooling wall and air cooling for rapid cooling, so that the cooling time in the traditional process is greatly shortened on the premise of realizing heat recovery. The deep cooling section is deeply cooled through fresh air and circulating air, and gradient utilization of slag heat is achieved. The high energy consumption of slag treatment is reduced, the metal recovery rate is improved, and the turnover time of the slag ladle is shortened.

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] Nonferrous metal smelting is an energy-intensive and highly polluting industry with great potential for energy conservation and emission reduction. Copper slag is an important by-product of the copper smelting process, with large output, high waste heat and metal recovery value. In the traditional copper slag treatment process, 1300°C slag is discharged from the furnace into the slag bag, and the slag truck transports the slag bag to the slag bag yard for natural cooling in the open air. When the slag temperature drops to 300-400°C, water is sprayed on the slag bag until it is completely cooled, and then the slag is flotated to recover copper and other metals. Finally, the slag is crushed and sold to the cement plant as cement iron-containing raw materials. The cooling time before and after the slag bag takes a total of 72 hours, during which a large amount of cooling water is consumed for spraying. The cooling water heated by the slag needs to be cooled and reused in a cooling tower. At present, the industry is basically unable to recycle the waste heat of slag, which is an industry problem, but this is also the direction of potential waste heat utilization for smelting enterprises.

[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] That is to say, the currently commonly used copper slag treatment process mainly adopts a combination of natural standing + spray cooling. However, this method does not recover the waste heat, and the slow cooling time and slow cooling rate are affected by the ambient temperature and cannot be controlled, resulting in the difficulty in controlling the copper crystallization efficiency, and thus the copper recovery rate cannot be guaranteed. At the same time, the cooling time of the rapid cooling stage of natural cooling is too long, which is not conducive to the turnover of the slag bag and increases the equipment investment cost. Summary of the invention

[0005] The object 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 comprises 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 deoxygenation 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 performs heat exchange between the slow cooling section and the heat collecting air duct. The water-cooled wall is arranged 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 superheater outlet merge 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 fan 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 at the rear side of the first gate;

[0013] When the first gate is opened 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 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.

[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 for stirring 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] The tops of the quick cooling section and the deep cooling section are both provided with circulating air blowing interfaces and circulating air suction interfaces at intervals.

[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 molten slag waste heat recovery system also 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, in the slow cooling section, a heat exchanger is used to exchange heat between the slow cooling section and the heat collecting air duct, so that the slag in the slow cooling section can be cooled by heat exchange. 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 reach the pre-designed 1-2°C / min. At the same time, because the circulating air is heat exchanged in the heat collecting air duct through the heat exchanger, it is not directly blown to the slag surface, which eliminates the local cooling of the slag, thereby eliminating the influence 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 the efficient use of heat, a combined cooling method of water-cooled wall plus air cooling is adopted for rapid cooling. On 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, in order to compensate for the air volume loss of the tunnel kiln during the heat exchange process, a fresh air fan is set at the outlet of the slag bag of the deep cooling section tunnel kiln to compensate for the air volume loss in the tunnel kiln. The cold air and circulating air generated by the fresh air fan are used to deeply cool the deep cooling section to achieve the cascade utilization of the slag heat. The high energy consumption of slag treatment is reduced, the metal recovery rate is improved, and the turnover time of the slag bag is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various objects, features and advantages of the present invention will become more apparent by considering the following detailed description of preferred embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings are merely exemplary illustrations of the present invention and are not necessarily drawn to scale. In the accompanying drawings, the same reference numerals always represent the same or similar parts.

[0037] in:

[0038] Figure 1 It is a schematic structural diagram of a kiln hood type high temperature slag waste heat recovery system according to an exemplary embodiment.

[0039] Figure 2 yes Figure 1 Elevation view of the layout of the slow cooling section.

[0040] Figure 3 yes Figure 1 The layout plan of the slow cooling section. DETAILED DESCRIPTION

[0041] Although the present invention can be easily embodied in different forms of embodiments, 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.

[0042] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0043] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various elements of the present invention are not absolute but relative. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indications of these directions also change accordingly.

[0044] See also Figures 1 to 3 The kiln hood type high temperature slag waste heat recovery system provided in 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 fan, and a deoxygenation drum.

[0045] 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 heat collecting air duct, and the water-cooled wall is arranged on the inner wall of the fast cooling section.

[0046] 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 quick cooling section. After heat exchange in the quick 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.

[0047] 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.

[0048] Through the above design, according to the characteristics of the slag at different stages, in the slow cooling section, the heat exchanger is used 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 the pre-designed 1-2°C / min. At the same time, because the circulating air is heat exchanged in the heat collecting air duct through the heat exchanger, it is not directly blown to the slag surface, which eliminates the local cooling of the slag, thereby eliminating the influence 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 the efficient use of heat, a combined cooling method of water-cooled wall plus air cooling is used for rapid cooling. On 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, in order to compensate for the air volume loss of the tunnel kiln during the heat exchange process, a fresh air fan is set at the outlet of the slag bag of the deep cooling section tunnel kiln to compensate for the air volume loss in the tunnel kiln. The cold air and circulating air generated by the fresh air fan are used to deeply cool the deep cooling section to achieve the cascade utilization of the slag heat. The high energy consumption of slag treatment is reduced, the metal recovery rate is improved, and the turnover time of the slag bag is reduced.

[0049] The three production sections of 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.

[0050] A conveyor track is laid in the tunnel kiln. The conveyor track passes through the slow cooling section, the fast cooling section and the deep cooling section, and the conveyor vehicle can move along the conveyor track. The kiln cover type high temperature slag waste heat recovery system also includes a scrap metal baler, which is used to transport the slag bag to the conveyor vehicle. The three production areas are connected by a conveyor track, which limits the movement trajectory of the conveyor vehicle and makes the movement of the conveyor vehicle smoother. The conveyor vehicle passes through each production area in sequence along the conveyor track in a heat-insulated and closed tunnel kiln.

[0051] It is worth mentioning that multiple conveyor vehicles can be connected to the conveying 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.

[0052] 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 at the rear side of the first gate. When the first gate is opened and the second gate is closed, the conveyor 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 conveyor vehicle moves from between the first gate and the second gate to the rear side of the second gate. During continuous operation, when it is necessary to deliver slag bags into the tunnel kiln, first the first gate is opened and the second gate is closed, and the conveyor vehicle transports the slag bags to between the first gate and the second gate, and the second gate prevents heat leakage in the tunnel kiln. Then the first gate is closed and the second gate is opened, and the conveyor vehicle transports the slag bags to the rear side of the second gate into the tunnel kiln, and the first gate prevents heat leakage in the tunnel kiln. In this way, large temperature fluctuations when the gates are opened can be reduced to ensure the continuity of heat supply.

[0053] Emergency ventilation holes are set on both sides of the slow cooling section. By monitoring the internal temperature of the slow cooling section, when the internal temperature of 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 there will be no over-temperature phenomenon in the slow cooling area and ensuring the safety of the structure.

[0054] 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. The high thermal conductivity of the heat pipe can be used to achieve effective heat exchange between the slow cooling section and the heat collecting air duct. At the same time, 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, can be measured by an infrared thermometer The temperature of the heat releasing end in the heat collecting air duct can be obtained, 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 the figure, and a one-sided arrangement is also possible.

[0055] In the early 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 to 2 / min by adjusting the wind speed of the heat collecting air duct set 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.

[0056] The kiln hood type high temperature slag waste heat recovery system also includes a stirrer, which is arranged in the slow cooling section and is used to stir the slag. According to the running speed of the slag bag, the stirrer can make the slag in the slag bag produce a rotation speed of 3 to 6 r / min, and promote the aggregation and growth of copper mineral particles in the slag bag through slow rotation, improve the crystallization efficiency of copper particles, etc., which is conducive to the subsequent flotation recovery of copper, thereby improving the copper recovery rate. In addition, after the copper slag surface is initially solidified to form a solid slag skin, the molten slag in the center of the copper slag can still be continuously stirred, so as to improve the overall recovery efficiency of copper in the entire slag bag, and overcome the adverse effects of the slag skin formed on the surface of the molten copper slag.

[0057] 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.

[0058] In this embodiment, the stirrer is an electromagnetic stirrer, which is composed of an electromagnetic coil. The electromagnetic stirrer can ensure that the molten copper slag has a constant rotation speed in the slag bag, and also prevent the influence of slag on the copper slag surface on the stirring of the copper slag, ensuring that the stirring process will not have the slag sticking problem existing in the mechanical stirring process. The rotation speed of the electromagnetic stirring can be controlled by controlling the voltage and current of the battery stirrer, ensuring the promotion effect of low-speed stirring on copper crystallization.

[0059] 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 the 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.

[0060] In this embodiment, water-cooled walls are provided on two opposite inner walls of the fast cooling section to further enhance the heat exchange effect.

[0061] The direction of the circulating air is specifically described in combination with the above embodiment: the air in the system is circulated and heated and cooled as a cooling medium in the entire heat exchange system through the blower and the induced draft fan. When the system reaches a stable state, the cold air of about 90°C is blown into the deep cooling section from the blower outlet. At the outlet of the deep cooling section, the induced draft fan is used to accelerate the extraction of the medium-temperature air of 100-150°C after the heat exchange inside the deep cooling section, and the medium-temperature air is blown into the fast cooling section. After being heated by the high-temperature slag, the hot air coming out of the fast cooling section reaches 250°C. At the same time, in the fast cooling section, the hot air also crosses the water-cooled wall area arranged on both sides of the fast cooling section during the heat absorption process through the high-temperature slag, thereby further enhancing the heat exchange effect. The medium-high temperature hot air of about 250°C coming out of the fast cooling section enters the evaporator through the regulating valve to heat the circulating water in the evaporator, and the other part enters the heat pipe heat collection air duct of the slow cooling section to further heat it to about 350°C. The hot air enters the superheater to further heat and heat the steam passing through the superheater, thereby improving the steam quality. The circulating air at the superheater outlet is cooled to about 200°C, and after merging with the circulating air at 150-180°C at the evaporator outlet, it enters the economizer together to preheat the desalted water. The circulating air coming out of the economizer is cooled to about 90°C, 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 installed in the deep cooling section at the tunnel kiln outlet to supplement the lost circulating air. After the circulating air is mixed with the fresh air, it is circulated and exchanged with the slag in the tunnel kiln in the deep cooling section.

[0062] Direction of circulating water: desalted water is mixed with steam drain return water in the pipeline to about 70℃, enters the desalted water tank and is transported to the economizer by the desalted water pump to be heated to about 100℃ and then sent to the deaeration drum; the hot water from the deaeration drum is sent to the water-cooled wall and evaporator by the boiler water pump, and is heated by the circulating air temperature of different temperatures and then returned to the deaeration drum. The water-cooled wall and evaporator absorb the heat of the corresponding waste heat system respectively to generate a steady stream of steam. The saturated steam at 180℃ in the drum is transported outward. When the steam output is too much, some of the excess steam enters the superheater and is heated to about 250℃. After further improving the steam quality, it is transported outward or stored in the heat accumulator.

[0063] 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 interval. For example, the temperatures of cold, medium temperature, medium-high temperature and high temperature increase in sequence.

[0064] Slag bag direction: The slag bag containing high-temperature molten slag is placed on the conveyor by a special vehicle. The conveyor enters the tunnel kiln along the long track. In the tunnel kiln, it is divided into three production sections according to the temperature of the copper slag: slow cooling section, fast cooling section, and deep cooling section. The conveyor passes through the slow cooling section, fast cooling section, and deep cooling section in turn. Taking the slag as copper slag as an example, through the multi-stage and efficient heat exchange system composed of economizer, deaerator drum, water-cooled wall, steamer, and superheater, the process processing time of the slow cooling section, fast cooling section, and deep cooling section is gradually reduced, and the processing time of copper slag is reduced from 72h of the traditional process to about 24h, which greatly improves the turnover efficiency of the slag bag. The slow cooling section controls the cooling time for 2-3h, the fast cooling section for 10-15h, and the deep cooling section for about 3-5h. Of course, 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 amount of steel slag (blast furnace slag and steel slag) produced by the steel and metallurgical industry. The kiln hood type high temperature slag waste heat recovery system is suitable for high temperature slag waste heat recovery and continuous operation process for improving recovery rate.

[0065] 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.

[0066] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should 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 fan, 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 performs heat exchange between the slow cooling section and the heat collecting air duct. The water-cooled wall is arranged 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 superheater outlet merge 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 fan 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 is 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 at the rear side of the first gate; When the first gate is opened 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 is 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 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.

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 is 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 for stirring 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; The tops of the quick cooling section and the deep cooling section are both provided with circulating air blowing interfaces and circulating air suction interfaces at intervals.

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 molten slag waste heat recovery system also includes a scrap metal baler, which is used to transport the slag bags to the conveyor vehicle.

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