Waste heat recovery method and waste heat recovery system

Abstract

The invention relates to the technical field of waste heat recovery, in particular to a waste heat recovery method and a waste heat recovery system. The waste heat recovery method comprises the following steps that hydrofluoric acid gas and aluminum hydroxide enter a fluidized bed to react, and aluminum fluoride is produced; aluminum fluoride enters a cooler to be cooled and exchanges heat with a heat exchange medium, the heat exchange medium after heat exchange enters a reboiler to exchange heat with liquid hydrofluoric acid, the liquid hydrofluoric acid is changed into hydrofluoric acid gas through heat exchange, and the hydrofluoric acid gas enters a fluidized bed to react with aluminum hydroxide; and the heat exchange medium which exchanges heat with the liquid hydrofluoric acid enters the cooler again to exchange heat with the aluminum fluoride. The heat exchange medium exchanges heat with the aluminum fluoride in the cooler, and the heat exchange medium after heat exchange enters the reboiler to exchange heat with the liquid hydrofluoric acid, so that the liquid hydrofluoric acid is changed into hydrofluoric acid gas, the heat of the aluminum fluoride is utilized, and meanwhile, the energy used for gasifying the liquid hydrofluoric acid is also saved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery, and in particular to a waste heat recovery method and a waste heat recovery system. Background Art

[0002] In the production process of aluminum fluoride, hydrofluoric acid gas and aluminum hydroxide are needed. Hydrofluoric acid gas and aluminum hydroxide react in a fluidized bed to generate aluminum fluoride at 550°C-600°C. Since the temperature of aluminum fluoride after the reaction is high, it is usually necessary to cool the aluminum fluoride before discharging it. During the cooling process, the heat energy of aluminum fluoride is gradually consumed and cannot be effectively utilized, resulting in energy waste. Summary of the invention

[0003] In view of this, the present invention provides a waste heat recovery method and a waste heat recovery system to solve the problem that the thermal energy of aluminum fluoride cannot be effectively utilized, resulting in energy waste.

[0004] In a first aspect, the present invention provides a waste heat recovery method, comprising the following steps:

[0005] Hydrofluoric acid gas and aluminum hydroxide enter the fluidized bed to react and produce aluminum fluoride;

[0006] Aluminum fluoride enters the cooler for cooling and exchanges heat with the heat exchange medium. The heat exchange medium after heat exchange enters the reboiler for heat exchange with liquid hydrofluoric acid. The liquid hydrofluoric acid is converted into hydrofluoric acid gas through heat exchange. The hydrofluoric acid gas enters the fluidized bed to react with aluminum hydroxide.

[0007] The heat exchange medium after heat exchange with liquid hydrofluoric acid enters the cooler again to exchange heat with aluminum fluoride.

[0008] Beneficial effects:

[0009] A heat exchange medium is used to exchange heat with aluminum fluoride in a cooler, and the heat exchange medium after heat exchange enters a reboiler to exchange heat with liquid hydrofluoric acid, so that the liquid hydrofluoric acid is converted into hydrofluoric acid gas, which not only utilizes the heat of aluminum fluoride but also saves the energy used to gasify the liquid hydrofluoric acid.

[0010] In an optional embodiment, the temperature of the heat exchange medium after heat exchange with liquid hydrofluoric acid is monitored. If the temperature of the heat exchange medium after heat exchange is higher than the set temperature, the heat exchange medium is cooled down; the temperature of the heat exchange medium after heat exchange with aluminum fluoride is monitored. If the temperature of the heat exchange medium after heat exchange is lower than the set temperature, the heat exchange medium is heated up.

[0011] Beneficial effects:

[0012] By real-time monitoring of the heat exchange medium, the heat exchange medium is heated or cooled according to the real-time temperature of the heat exchange medium to ensure that the temperature of the heat exchange medium is maintained at the set temperature, so that the heat exchange medium can fully vaporize the liquid hydrofluoric acid when exchanging heat with the liquid hydrofluoric acid, and at the same time, when exchanging heat with aluminum fluoride, the aluminum fluoride can be cooled more quickly, effectively improving the heat exchange efficiency.

[0013] In an optional embodiment, the volume of the heat exchange medium is monitored, and if the volume of the heat exchange medium exceeds a set value, the excess heat exchange medium enters a recovery pool.

[0014] Beneficial effects:

[0015] By recycling the excess heat exchange medium into the recovery pool, changes in circulation velocity and pressure caused by excessive heat exchange medium can be avoided, which affects the heat exchange efficiency. At the same time, the recovery pool can store heat exchange medium. When the volume of the heat exchange medium being exchanged is reduced, the heat exchange medium in the recovery pool can be added.

[0016] In an optional embodiment, when the heat exchange medium needs to be cooled, the heat exchange medium in the recovery pool is merged with the heat exchange medium that needs to be cooled to reduce the temperature.

[0017] Beneficial effects:

[0018] By using the heat exchange medium in the recovery pool for cooling, internal circulation of the heat exchange medium can be achieved, the steps are simple, and the heat exchange medium in the recovery pool can be effectively utilized.

[0019] In an optional embodiment, when the temperature of the heat exchange medium needs to be increased, the external steam is combined with the heat exchange medium to increase the temperature.

[0020] Beneficial effect: By heating the steam produced by other processes with the heat exchange medium, energy is effectively utilized and ineffective waste of energy is avoided.

[0021] In a second aspect, the present invention further provides a waste heat recovery system, which is applied to the waste heat recovery method in any of the above schemes, comprising:

[0022] Fluidized bed;

[0023] a cooler, the cooler being in communication with the fluidized bed;

[0024] A heat exchange pipeline, the heat exchange pipeline is connected to the cooler, and a heat exchange medium is contained in the heat exchange pipeline;

[0025] A reboiler is communicated with the fluidized bed, and the heat exchange pipeline is connected with the reboiler.

[0026] Since the waste heat recovery system includes the waste heat recovery method, and has the same effect as the waste heat recovery method, it will not be described in detail here.

[0027] In an optional embodiment, the heat exchange pipeline comprises a first pipeline and a second pipeline, the first pipeline and the second pipeline are connected end to end, the water inlet end of the first pipeline is connected to the water outlet end of the second pipeline, and the water outlet end of the first pipeline is connected to the water inlet end of the second pipeline;

[0028] The heat exchange medium exchanges heat with the reboiler when flowing from the first pipeline to the second pipeline, and exchanges heat with the cooler when flowing from the second pipeline to the first pipeline.

[0029] In an optional embodiment, a temperature monitoring structure is provided on the first pipeline and the second pipeline, the first pipeline is connected to a heating component, and the second pipeline is connected to a cooling component.

[0030] In an optional embodiment, the cooling component has a recovery tank, a recovery pipeline and a cooling pipeline, the first pipeline and the second pipeline are respectively connected to the recovery tank through the recovery pipeline, and the two ends of the cooling pipeline are respectively connected to the recovery tank and the second pipeline.

[0031] In an optional embodiment, the heating component has a steam delivery pipeline, and the steam delivery pipeline is connected to the first pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic diagram of a waste heat recovery method according to an embodiment of the present invention;

[0034] Description of reference numerals:

[0035] 1. Fluidized bed; 2. Hydrofluoric acid gas; 3. Aluminum hydroxide; 4. Aluminum fluoride; 5. Cooler; 6. Heat exchange medium; 7. Reboiler; 8. Liquid hydrofluoric acid; 9. Recovery tank; 10. Heat exchange pipeline; 101. First pipeline; 102. Second pipeline; 11. Cooling component; 1101. Cooling pipeline; 12. Recovery pipeline; 13. Steam delivery pipeline. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0037] Combine the following Figure 1 , describing an embodiment of the present invention.

[0038] According to an embodiment of the present invention, on the one hand, a waste heat recovery method is provided, comprising the following steps:

[0039] Hydrofluoric acid gas 2 and aluminum hydroxide 3 enter into fluidized bed 1 to react and produce aluminum fluoride 4;

[0040] Aluminum fluoride 4 enters cooler 5 for cooling and exchanges heat with heat exchange medium 6. After heat exchange, heat exchange medium 6 enters reboiler 7 for heat exchange with liquid hydrofluoric acid 8. Liquid hydrofluoric acid 8 is converted into hydrofluoric acid gas 2 through heat exchange. Hydrofluoric acid gas 2 enters fluidized bed 1 to react with aluminum hydroxide 3.

[0041] After exchanging heat with the liquid hydrofluoric acid 8 , the heat exchange medium 6 enters the cooler 5 again to exchange heat with the aluminum fluoride 4 .

[0042] In this embodiment, hydrofluoric acid gas 2 and aluminum hydroxide 3 enter the fluidized bed 1 to react and generate aluminum fluoride 4 with a temperature of 550°C-600°C. Subsequently, the aluminum fluoride 4 enters the cooler 5 for cooling. The heat exchange medium 6 enters the cooler 5 for heat exchange with the aluminum fluoride 4 at 550°C-600°C. The aluminum fluoride 4 in the cooler 5 continues to cool down until it is discharged from the cooler 5 after being reduced to a specified temperature. The temperature of the heat exchange medium 6 after the heat exchange increases and enters the reboiler 7 to exchange heat with the liquid hydrofluoric acid 8 in the reboiler 7, so that the liquid hydrofluoric acid 8 absorbs heat and becomes hydrofluoric acid gas 2. The hydrofluoric acid gas 2 then enters the fluidized bed 1 to react with the aluminum hydroxide 3. The heat exchange medium 6 after heat exchange with the liquid hydrofluoric acid 8 will enter the cooler 5 again for heat exchange with the aluminum fluoride 4.

[0043] Preferably, the cooler 5 is a plate cooler 5 .

[0044] It should be noted that the heat exchange medium 6 is used to exchange heat with the aluminum fluoride 4 in the cooler 5. The heat exchange medium 6 after heat exchange enters the reboiler 7 to exchange heat with the liquid hydrofluoric acid 8, so that the liquid hydrofluoric acid 8 is converted into hydrofluoric acid gas 2. While utilizing the heat of the aluminum fluoride 4, the energy used to gasify the liquid hydrofluoric acid 8 is also saved.

[0045] In some embodiments, the temperature of the heat exchange medium 6 after heat exchange with the liquid hydrofluoric acid 8 is monitored. If the temperature of the heat exchange medium 6 after heat exchange is higher than the set temperature, the heat exchange medium 6 is cooled down; the temperature of the heat exchange medium 6 after heat exchange with the aluminum fluoride 4 is monitored. If the temperature of the heat exchange medium 6 after heat exchange is lower than the set temperature, the heat exchange medium 6 is heated up.

[0046] In this embodiment, the temperature of the heat exchange medium 6 after heat exchange with aluminum fluoride 4 is monitored in real time, and the temperature is set to 90°C. If the temperature of the heat exchange medium 6 is monitored to be lower than 90°C, the temperature of the heat exchange medium 6 is increased to maintain its temperature at 90°C; the temperature of the heat exchange medium 6 after heat exchange with liquid hydrofluoric acid 8 is monitored in real time, and the temperature is set to 60°C. If the temperature of the heat exchange medium 6 is monitored to be higher than 60°C, an external cooling pipeline 1101 is connected to add cold water to the heat exchange medium 6 to reduce the temperature of the heat exchange medium 6 to maintain its temperature at 90°C.

[0047] Preferably, the heat exchange medium 6 is water.

[0048] It should be noted that, by real-time monitoring of the heat exchange medium 6, the heat exchange medium 6 is heated or cooled according to the real-time temperature of the heat exchange medium 6 to ensure that the temperature of the heat exchange medium 6 is maintained at the set temperature, so that the heat exchange medium 6 can fully vaporize the liquid hydrofluoric acid 8 when exchanging heat with the liquid hydrofluoric acid 8. At the same time, when exchanging heat with the aluminum fluoride 4, the heat exchange medium 6 with a low temperature can cool the aluminum fluoride 4 more quickly, thereby effectively improving the heat exchange efficiency.

[0049] In some embodiments, when the temperature of the heat exchange medium 6 needs to be increased, the external steam is combined with the heat exchange medium 6 to increase the temperature.

[0050] In this embodiment, when the heat exchange medium 6 needs to be heated, an external steam delivery pipeline 13 is connected to heat the heat exchange medium 6 with steam produced by other processes. By heating the steam produced by other processes and the heat exchange medium 6, energy is effectively utilized and ineffective waste of energy is avoided.

[0051] In some embodiments, the volume of the heat exchange medium 6 is monitored. If the volume of the heat exchange medium 6 exceeds a set value, the excess heat exchange medium 6 enters the recovery tank 9 .

[0052] In the present embodiment, water vapor is used to heat the heat exchange medium 6, and the water vapor contains a large amount of water. When the heat exchange medium 6 is heated, the water in the water vapor condenses into liquid water and is added to the heat exchange medium 6, causing the volume of the heat exchange medium 6 to increase. When the heat exchange medium 6 is cooled, cold water is used to cool the heat exchange medium 6. The cold water merges with the heat exchange medium 6, causing the volume of the heat exchange medium 6 to increase. Therefore, it is necessary to monitor the volume of the heat exchange medium 6 in real time. When the volume of the heat exchange medium 6 exceeds the set value, the excess heat exchange medium 6 will enter the recovery pool 9 for storage. When the volume of the heat exchange medium 6 in the heat exchange pipeline 10 is less than the set value, the heat exchange medium 6 in the recovery pool 9 can be added.

[0053] It should be noted that by recycling the excess heat exchange medium 6 into the recovery pool 9, changes in circulation velocity and pressure caused by excessive heat exchange medium 6 can be avoided, which affects the heat exchange efficiency. At the same time, the recovery pool 9 can store the heat exchange medium 6. When the volume of the heat exchange medium 6 being exchanged is reduced, the heat exchange medium 6 in the recovery pool 9 can be added.

[0054] In some embodiments, when the heat exchange medium 6 needs to be cooled, the heat exchange medium 6 in the recovery pool 9 merges with the heat exchange medium 6 that needs to be cooled to lower the temperature.

[0055] In this embodiment, after the temperature of the heat exchange medium 6 is increased, if it is monitored that the volume of the heat exchange medium 6 exceeds the set value, the excess heat exchange medium 6 will enter the recovery pool 9 for storage and cooling. When it is monitored that the temperature of the heat exchange medium 6 after heat exchange with the liquid hydrofluoric acid 8 is higher than the set temperature, the cooled heat exchange medium 6 in the recovery pool 9 will pass through the cooling pipeline 1101 and merge with the heat exchange medium 6 after heat exchange with the liquid hydrofluoric acid 8 to reduce the temperature of the heat exchange medium 6 after heat exchange with the liquid hydrofluoric acid 8. When it is monitored that the volume of the cooled heat exchange medium 6 exceeds the set value, the excess heat exchange medium 6 will enter the recovery pool 9 for storage and cooling, waiting for the next cooling of the heat exchange medium 6.

[0056] It should be noted that by using the heat exchange medium 6 in the recovery tank 9 for cooling, internal circulation of the heat exchange medium 6 can be achieved, the steps are simple, and the heat exchange medium 6 in the recovery tank 9 can be effectively utilized.

[0057] According to an embodiment of the present invention, on the other hand, Figure 1 As shown, a waste heat recovery system is also provided, which is applied to the waste heat recovery method described in the above embodiment, including: a fluidized bed 1, a cooler 5, a heat exchange pipeline 10 and a reboiler 7.

[0058] Specifically, the cooler 5 is in communication with the fluidized bed 1. The heat exchange pipeline 10 is connected to the cooler 5, and the heat exchange pipeline 10 has a heat exchange medium 6. The reboiler 7 is in communication with the fluidized bed 1, and the heat exchange pipeline 10 is connected to the reboiler 7.

[0059] In this embodiment, the material conveying equipment is connected to the fluidized bed 1 to convey the aluminum hydroxide 3 to the fluidized bed 1, the reboiler 7 is connected to the fluidized bed 1, the hydrofluoric acid gas 2 in the reboiler 7 will enter the fluidized bed 1 to react with the aluminum hydroxide 3 to generate aluminum fluoride 4, the fluidized bed 1 is connected to the cooler 5, the aluminum fluoride 4 can enter the cooler 5 for cooling, the material storage assembly is connected to the cooler 5, and the cooled aluminum fluoride 4 will enter the material storage assembly. The heat exchange pipeline 10 is connected to the cooler 5 and the reboiler 7 respectively, and the heat exchange pipeline 10 has a heat exchange medium 6. After the heat exchange medium 6 exchanges heat with the aluminum fluoride 4 in the cooler 5 and heats up, it flows to the reboiler 7 through the heat exchange pipeline 10, and liquid hydrofluoric acid 8 is added to the reboiler 7. The liquid hydrofluoric acid 8 exchanges heat with the heat exchange medium 6 in the heat exchange pipeline 10, gasifies into hydrofluoric acid gas 2 and enters the fluidized bed 1 to react. After the heat exchange medium 6 exchanges heat with the liquid hydrofluoric acid 8 in the reboiler 7 , it flows into the cooler 5 to exchange heat with the aluminum fluoride 4 again.

[0060] In some embodiments, the heat exchange pipeline 10 has a first pipeline 101 and a second pipeline 102, the first pipeline 101 and the second pipeline 102 are connected end to end, the water inlet end of the first pipeline 101 is connected to the water outlet end of the second pipeline 102, and the water outlet end of the first pipeline 101 is connected to the water inlet end of the second pipeline 102, wherein the heat exchange medium 6 exchanges heat with the reboiler 7 when flowing from the first pipeline 101 to the second pipeline 102, and exchanges heat with the cooler 5 when flowing from the second pipeline 102 to the first pipeline 101.

[0061] In this embodiment, the heat exchange pipeline 10 has a first pipeline 101 and a second pipeline 102, the first pipeline 101 and the second pipeline 102 are connected end to end, the heat exchange medium 6 can circulate in the first pipeline 101 and the second pipeline 102, the water inlet end of the first pipeline 101 is connected to the water outlet end of the second pipeline 102, the water outlet end of the first pipeline 101 is connected to the water inlet end of the second pipeline 102, the heat exchange medium 6 exchanges heat with the liquid hydrofluoric acid 8 in the reboiler 7 when flowing from the first pipeline 101 to the second pipeline 102, and exchanges heat with the aluminum fluoride 4 in the cooler 5 when flowing from the second pipeline 102 to the first pipeline 101.

[0062] Specifically, the heat exchange pipeline 10 is connected to a water pump, and the water pump can drive the heat exchange medium 6 in the heat exchange pipeline 10 to circulate.

[0063] In some embodiments, the first pipeline 101 and the second pipeline 102 have temperature monitoring structures, the first pipeline 101 is connected to the heating component, and the second pipeline 102 is connected to the cooling component 11 .

[0064] In this embodiment, a temperature monitoring structure is provided on the first pipeline 101 and the second pipeline 102 respectively. The temperature monitoring structure can monitor the temperature of the heat exchange medium 6 in the first pipeline 101 and the second pipeline 102 in real time. The temperature monitoring structure is connected to the control system. The temperature monitoring structure can transmit the monitored temperature information to the control system. The first pipeline 101 and the second pipeline 102 are respectively connected to the heating component and the cooling component 11. The heating component and the cooling component 11 are connected to the control system signal. The control system can compare the temperature data transmitted by the temperature monitoring structure with the set temperature. If the temperature of the heat exchange medium 6 in the first pipeline 101 is lower than the set temperature, the control system controls the heating component to increase the temperature of the heat exchange medium 6 in the first pipeline 101; if the temperature of the heat exchange medium 6 in the second pipeline 102 is higher than the set temperature, the control system controls the cooling component 11 to cool the heat exchange medium 6 in the second pipeline 102.

[0065] Preferably, the temperature monitoring structure is a temperature monitor.

[0066] Specifically, the set temperature in the first pipeline 101 is 90° C., and the set temperature in the second pipeline 102 is 60° C. The set temperature can be input into the control system to facilitate the control system to compare the set temperature with the temperature information transmitted by the temperature monitoring structure. In other optional embodiments, the set temperatures in the first pipeline 101 and the second pipeline 102 can be any temperature as long as they meet the process requirements.

[0067] In some embodiments, the cooling component 11 has a recovery tank 9, a recovery pipeline 12 and a cooling pipeline 1101. The first pipeline 101 and the second pipeline 102 are respectively connected to the recovery tank 9 through the recovery pipeline 12, and the two ends of the cooling pipeline 1101 are respectively connected to the recovery tank 9 and the second pipeline 102.

[0068] In this embodiment, the recovery pool 9 is connected to the first pipeline 101 and the second pipeline 102 respectively through the recovery pipeline 12. Flow meters are also provided on the first pipeline 101 and the second pipeline 102. The flow meters are connected to the control system. The flow meters can transmit the monitored information to the control system. The control system compares the received information with the set value. If the volume of the heat exchange medium 6 in the first pipeline 101 and / or the second pipeline 102 exceeds the set value, the control system opens the recovery pipeline 12, so that the excess heat exchange medium 6 in the first pipeline 101 and / or the second pipeline 102 enters the recovery pool 9 through the recovery pipeline 12. The recovery pool 9 can store and cool the heat exchange medium 6. The two ends of the cooling pipeline 1101 are respectively connected to the recovery tank 9 and the second pipeline 102. A water pump is arranged on the cooling pipeline 1101. When the control system detects that the temperature of the heat exchange medium 6 in the second pipeline 102 is higher than the set temperature, the cooling pipeline 1101 is opened, and the water pump is controlled to flow the cooled heat exchange medium 6 in the recovery tank 9 into the second pipeline 102, and merge with the heat exchange medium 6 in the second pipeline 102 that needs to be cooled, thereby reducing the temperature of the heat exchange medium 6 in the second pipeline 102. After the temperature of the heat exchange medium 6 is reduced to the set temperature, the control system closes the cooling pipeline 1101.

[0069] In some embodiments, the heating component has a steam delivery pipeline 13 , and the steam delivery pipeline 13 is connected to the first pipeline 101 .

[0070] In this embodiment, one end of the steam delivery pipeline 13 is connected to the first pipeline 101, and the other end of the steam delivery pipeline 13 is connected to the steam output device. When the control system detects that the temperature of the heat exchange medium 6 in the first pipeline 101 is lower than the set temperature, the steam delivery pipeline 13 is opened, and the steam in the steam delivery pipeline 13 enters the first pipeline 101 to heat the heat exchange medium 6 in the first pipeline 101, so that the heat exchange medium 6 is heated until the temperature of the heat exchange medium 6 reaches the set temperature.

[0071] Specifically, a control valve is provided at the connection between the first pipeline 101 and the steam delivery pipeline 13 and the recovery pipeline 12, and a control valve is provided at the connection between the second pipeline 102 and the cooling pipeline 1101 and the recovery pipeline 12. The control system is connected to the control valve to control the opening or closing of the control valve.

[0072] In other embodiments, a manual valve is provided at the connection between the first pipeline 101 and the steam delivery pipeline 13 and the recovery pipeline 12 , and a manual valve is provided at the connection between the second pipeline 102 and the cooling pipeline 1101 and the recovery pipeline 12 .

[0073] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A waste heat recovery method, characterized in that: The following steps are involved: Hydrofluoric acid gas (2) and aluminum hydroxide (3) enter into a fluidized bed (1) to react and produce aluminum fluoride (4); Aluminum fluoride (4) enters a cooler (5) to be cooled and to exchange heat with a heat exchange medium (6). After the heat exchange, the heat exchange medium (6) enters a reboiler (7) to exchange heat with liquid hydrofluoric acid (8). The liquid hydrofluoric acid (8) is converted into hydrofluoric acid gas (2) through the heat exchange. The hydrofluoric acid gas (2) enters a fluidized bed (1) to react with aluminum hydroxide (3). The heat exchange medium (6) after heat exchange with the liquid hydrofluoric acid (8) enters the cooler (5) again to exchange heat with the aluminum fluoride (4).

2. The waste heat recovery method according to claim 1, characterized in that: The temperature of the heat exchange medium (6) after heat exchange with the liquid hydrofluoric acid (8) is monitored. If the temperature of the heat exchange medium (6) after heat exchange is higher than the set temperature, the temperature of the heat exchange medium (6) is lowered. The temperature of the heat exchange medium (6) after heat exchange with the aluminum fluoride (4) is monitored. If the temperature of the heat exchange medium (6) after heat exchange is lower than the set temperature, the temperature of the heat exchange medium (6) is raised.

3. The waste heat recovery method according to claim 2, characterized in that: The volume of the heat exchange medium (6) is monitored. If the volume of the heat exchange medium (6) exceeds a set value, the excess heat exchange medium (6) enters a recovery pool (9).

4. The waste heat recovery method according to claim 3, characterized in that: When the heat exchange medium (6) needs to be cooled, the heat exchange medium (6) in the recovery pool (9) merges with the heat exchange medium (6) that needs to be cooled to reduce the temperature.

5. The waste heat recovery method according to claim 2, characterized in that: When the temperature of the heat exchange medium (6) needs to be increased, the external steam merges with the heat exchange medium (6) to increase the temperature.

6. A waste heat recovery system, applied to the waste heat recovery method according to any one of claims 1 to 5, characterized in that: include: Fluidized bed (1); a cooler (5), the cooler (5) being in communication with the fluidized bed (1); A heat exchange pipeline (10), the heat exchange pipeline (10) being connected to the cooler (5), and containing a heat exchange medium (6); A reboiler (7), the reboiler (7) is in communication with the fluidized bed (1), and the heat exchange pipeline (10) is connected to the reboiler (7).

7. The waste heat recovery system according to claim 6, characterized in that: The heat exchange pipeline (10) comprises a first pipeline (101) and a second pipeline (102), the first pipeline (101) and the second pipeline (102) are connected end to end, the water inlet end of the first pipeline (101) is connected to the water outlet end of the second pipeline (102), and the water outlet end of the first pipeline (101) is connected to the water inlet end of the second pipeline (102); The heat exchange medium (6) exchanges heat with the reboiler (7) when flowing from the first pipeline (101) to the second pipeline (102), and the heat exchange medium (6) exchanges heat with the cooler (5) when flowing from the second pipeline (102) to the first pipeline (101).

8. The waste heat recovery system according to claim 7, characterized in that: The first pipeline (101) and the second pipeline (102) are provided with temperature monitoring structures; the first pipeline (101) is connected to a heating component, and the second pipeline (102) is connected to a cooling component (11).

9. The waste heat recovery system according to claim 8, characterized in that: The cooling component (11) comprises a recovery tank (9), a recovery pipeline (12) and a cooling pipeline (1101); the first pipeline (101) and the second pipeline (102) are respectively connected to the recovery tank (9) via the recovery pipeline (12); and the two ends of the cooling pipeline (1101) are respectively connected to the recovery tank (9) and the second pipeline (102).

10. The waste heat recovery system according to claim 8, characterized in that: The heating component has a steam delivery pipeline (13), and the steam delivery pipeline (13) is connected to the first pipeline (101).

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