Waste heat recovery method and device

Abstract

The invention relates to a waste heat recovery method and device. The waste heat recovery method comprises the following steps that S1, argon is introduced into a crystal through a first pipeline in the growth process of the crystal in the single crystal furnace, argon introduction is stopped after crystal growth is completed, the single crystal furnace is externally connected with a cooling pipeline, a gas outlet of the single crystal furnace is further communicated with a thermoelectric power generation mechanism, and the thermoelectric power generation mechanism is electrically connected with an energy storage device; s2, cooling liquid is introduced into the cooling pipeline, the cooling liquid is vaporized into first gas with heat, and the first gas flows into the thermoelectric power generation mechanism; and S3, the thermoelectric power generation mechanism converts heat of the first gas into electric energy and stores the electric energy in the energy storage device. By means of the arrangement, waste heat recovery after the single crystal furnace is shut down is completed, and waste of heat energy is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of energy recovery and utilization, and in particular to a waste heat recovery method and device. Background Art

[0002] At present, the mainstream method used in photovoltaic solar energy and semiconductor silicon wafer production is the Czochralski method to pull single crystal silicon rods. During the Czochralski single crystal silicon preparation process, the single crystal furnace heat field is in a high temperature and high purity environment, and the pulling temperature can reach 1600℃. After the crystal pulling is completed, the heat field temperature needs to be lowered to below room temperature to ensure that the heat field components are not oxidized and do not affect the dismantling and cleaning of the furnace.

[0003] At present, the cooling method of the thermal field is to continuously introduce argon gas and continuously start circulating water inside the furnace to achieve cooling after the single crystal furnace is shut down. The entire shutdown cooling time generally exceeds 9 hours, and the above cooling process will also cause a large amount of heat energy to be naturally lost, resulting in a waste of resources. Summary of the invention

[0004] Based on this, it is necessary to provide a waste heat recovery method and device to address the problems of slow cooling speed and heat loss leading to waste of resources in the current single crystal furnace cooling method.

[0005] A waste heat recovery method, the waste heat recovery method comprising the following steps:

[0006] S1. During the growth of the crystal in the single crystal furnace, argon gas is introduced through the first pipe. After the growth of the crystal is completed, the introduction of the argon gas is stopped. The single crystal furnace is externally connected to a cooling pipe. The gas outlet of the single crystal furnace is also connected to a temperature difference power generation mechanism, and the temperature difference power generation mechanism is electrically connected to an energy storage device.

[0007] S2, passing a coolant into the cooling pipe, wherein the coolant vaporizes into a first gas having heat and flows into the temperature difference power generation mechanism;

[0008] S3. The temperature difference power generation mechanism converts the heat of the first gas into electrical energy and stores it in the energy storage device.

[0009] The above-mentioned waste heat recovery method, by laying a cooling pipe in the single crystal furnace, passing a coolant into the cooling pipe, and utilizing the coolant to absorb heat by evaporation to reduce the furnace temperature inside the single crystal furnace, thereby improving the cooling efficiency, and then passing the first gas with high temperature generated after the coolant is vaporized into a temperature difference power generation mechanism, and utilizing the temperature difference power generation mechanism to convert the high heat of the first gas into electrical energy and store it in an energy storage device, so as to complete the waste heat recovery after the single crystal furnace is shut down, thereby also avoiding the waste of heat energy.

[0010] In one embodiment, the coolant is any one of liquid nitrogen, liquid helium, liquid carbon dioxide, and liquid Freon.

[0011] In one of the embodiments, step S2 specifically includes the following steps: the gas outlet is provided with a gas conveying device, and the gas conveying device inputs the first gas into the temperature difference power generation mechanism.

[0012] In one embodiment, in step S2, the following steps are also included:

[0013] S21, after a preset amount of the coolant is introduced into the cooling pipe, the coolant is stopped from being introduced further;

[0014] S22. After the coolant stops flowing in, the gas delivery device waits for a set time and then inputs the first gas into the temperature difference power generation mechanism at a first flow rate.

[0015] In one embodiment, step S21 and step S22 are used as a cycle unit to perform multiple cycles.

[0016] In one embodiment, the set time ranges from 30 minutes to 60 minutes.

[0017] In one embodiment, in step S2, the following steps are also included:

[0018] S21, continuously introducing the coolant into the cooling pipe;

[0019] S22. The gas delivery device continuously inputs the first gas into the temperature difference power generation mechanism at a second flow rate.

[0020] In one embodiment, the second flow rate ranges from 80 lmp to 120 lmp.

[0021] The present application also provides a waste heat recovery device for implementing the waste heat recovery method described in any of the above embodiments, wherein the waste heat recovery device is installed in a single crystal furnace:

[0022] The single crystal furnace comprises a furnace body and a furnace cover arranged on the furnace body, the inner wall of the furnace body is provided with a heat preservation tube, a reaction crucible, a heater and a cooling component are arranged in the heat preservation tube, the heater is arranged on the outer periphery of the crucible, the cooling component is located on the top of the crucible, and a heat preservation soft felt and the gas outlet are arranged at the bottom of the furnace body;

[0023] The waste heat recovery device includes a cooling pipe, a temperature difference power generation mechanism connected to the air outlet, and an energy storage device electrically connected to the temperature difference power generation mechanism. The cooling pipe is used to pass a coolant. After the coolant is vaporized into a first gas, it passes through the furnace cover, the cooling assembly, the reaction crucible, the heater, the insulation tube in sequence, and flows along the inner wall of the insulation tube to the insulation soft felt and the air outlet.

[0024] In one embodiment, the temperature difference power generation mechanism includes a primary temperature difference chamber, a secondary temperature difference chamber and a tertiary temperature difference chamber arranged in sequence, and each temperature difference chamber has a high temperature chamber and a low temperature chamber that are not connected to each other, wherein:

[0025] The high temperature chambers of each temperature difference chamber are connected, and the high temperature chambers are also connected to the air outlet;

[0026] The low temperature cavity of each temperature difference chamber is connected to the external air flow;

[0027] A thermocouple electrically connected to the energy storage device is disposed in each of the temperature difference chambers, one end of the thermocouple is disposed in the high temperature chamber, and the other end of the thermocouple is disposed in the low temperature chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the waste heat recovery method provided in this application.

[0029] Figure 2 This is a cross-sectional view of the single crystal furnace provided in this application.

[0030] Figure 3 This is a schematic diagram of the flow of the first gas in the single crystal furnace provided in this application.

[0031] 10. Single crystal furnace;

[0032] 100, furnace body; 200, furnace cover; 210, throat; 300, insulation tube; 310, upper insulation body; 320, middle insulation body; 330, lower insulation body; 400, reaction crucible; 500, main heater; 600, cooling assembly; 610, heat exchanger; 620, guide tube; 700, insulation soft felt; 800, air outlet; 900, cooling low heater. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0035] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0037] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0039] See also Figure 1 As shown, Figure 1 A flowchart of a waste heat recovery method provided in one embodiment of the present application. The waste heat recovery method provided in one embodiment of the present application comprises the following steps:

[0040] Step S1, during the growth of the crystal in the single crystal furnace, argon gas is introduced through the first pipeline. After the crystal growth is completed, the single crystal furnace is stopped and the introduction of argon gas is stopped. It should be noted that the water cooling circulation system in the single crystal furnace is always enabled to speed up the cooling of the single crystal furnace. In addition, the single crystal furnace of the present application is externally connected to a cooling pipeline, and the cooling pipeline and the first pipeline are installed in the single crystal furnace through a transfer valve. The gas outlet of the single crystal furnace is also connected to a temperature difference power generation mechanism, and the temperature difference power generation mechanism is electrically connected to the energy storage device;

[0041] Step S2, passing the coolant into the cooling pipe, the coolant is vaporized into a first gas with heat and flows into the temperature difference power generation mechanism. It should be noted that the temperature of the single crystal furnace after the crystal pulling is completed is still at a high temperature of about 1600°C, and the above temperature can completely vaporize the coolant, and the first gas formed after vaporization is also a high-temperature gas, so that the first gas has heat, and at the same time, the process of vaporizing the coolant into the first gas will absorb heat, which is conducive to the rapid cooling of the single crystal furnace, shortening the cooling time of the single crystal furnace, and improving the cooling efficiency; in the specific setting, the cooling pipe for passing the coolant and the first pipe for passing argon are arranged at intervals in the present application. Through the above setting, in specific use, the first pipe is used to pass argon in the crystal pulling process to ensure the normal progress of the crystal pulling process, and after the crystal growth is completed, the cooling pipe is used to pass the coolant for rapid cooling, and the two do not interfere with each other. The setting of the coolant will not affect the original crystal pulling process and the quality of the crystal pulling;

[0042] Step S3: The temperature difference power generation mechanism converts the heat of the first gas into electrical energy and stores it in the energy storage device to complete the waste heat recovery after the single crystal furnace is shut down.

[0043] The above-mentioned waste heat recovery method, by setting an external cooling pipe for the single crystal furnace, passing a coolant into the cooling pipe, and utilizing the heat absorption of the coolant by evaporation to reduce the furnace temperature inside the single crystal furnace, thereby improving the cooling efficiency, and then passing the first gas with high temperature generated after the coolant is vaporized into a temperature difference power generation mechanism, and utilizing the temperature difference power generation mechanism to convert the high heat of the first gas into electrical energy and store it in an energy storage device, so as to complete the waste heat recovery after the single crystal furnace is shut down, thereby also avoiding the waste of heat energy.

[0044] In order to speed up the cooling down during the shutdown cooling stage, in a preferred embodiment, the coolant is any one of liquid nitrogen, liquid helium, liquid carbon dioxide, and liquid Freon. It should be emphasized that the coolant is not limited to the above liquids, and has stable chemical properties, is not easy to react and introduce impurities, and has a large temperature difference between the gas and liquid states, so that any refrigerant that needs to absorb a large amount of heat energy for vaporization can be used.

[0045] In order to facilitate the first gas formed in the cooling pipeline to flow into the temperature difference power generation mechanism, in step S2, the following steps are specifically included: a gas delivery device is provided on the gas outlet, and the gas delivery device inputs the first gas into the temperature difference power generation mechanism. It should be noted that the gas delivery device can be a gas delivery pump that can deliver the first gas at a set flow rate.

[0046] In the specific setting, in order for the coolant to sufficiently cool down each area in the single crystal furnace, specifically, in step S2, the following steps are also included:

[0047] Step S21: After a preset amount of coolant is introduced into the cooling pipe, the coolant is stopped from being introduced. It should be noted that the specific preset amount of coolant is selected according to the size and shape of the single crystal furnace, and no excessive settings are made here; Step S22: After the coolant stops being introduced, the gas delivery device waits for a set time before inputting the first gas into the temperature difference power generation mechanism at a first flow rate. Through the above settings, the set time that the gas delivery device waits is the time that the coolant stays in the single crystal furnace, which can fully absorb heat to cool the single crystal furnace, and achieves the goal of using a small amount of coolant to thoroughly cool the single crystal furnace.

[0048] In specific settings, the setting time is preferably in the range of 30min-60min, and the specific setting time can be any value among 40min, 50min, 55min, 58min and 30min-60min, so as to ensure that the coolant fully absorbs heat. After the coolant fully absorbs heat after the above setting time, the gas delivery device delivers the first gas to the temperature difference power generation mechanism at a flow rate of 40lpm-65lp, and the specific flow rate can be any value among 45lpm, 50lpm, 60lpm, 63lpm and 40lpm-65lp, so as to ensure the transmission efficiency while not affecting the heat absorption of the coolant.

[0049] In order to ensure the cooling efficiency of the single crystal furnace, more specifically, multiple cycles of cooling are performed with step S21 and step S22 as circulation units. In specific settings, the number of cycles can be 2, 3 or more. When the residence time of the first gas in the furnace is preferably 30 minutes, and the flow rate of the first gas delivered to the temperature difference power generation mechanism is preferably 50 lpm, the present application uses step S21 and step S22 as circulation units to perform two cycles to achieve rapid cooling of the single crystal furnace, so that the entire cooling process can be completed in about 2 hours, which greatly reduces the cooling time and improves the cooling efficiency.

[0050] In order to instantly take away a large amount of heat energy in the single crystal furnace, specifically, in step S2, the following steps can also be set: step S21, continuously introduce coolant into the cooling pipe; step S22, the gas delivery device continuously inputs the first gas into the temperature difference power generation mechanism at a second flow rate. Through the above settings, the coolant continuously flows into the temperature difference power generation mechanism through the gas delivery device. Compared with the previous embodiment in which the coolant stays for a set time before being delivered to the temperature difference power generation mechanism, although the amount of coolant used is increased, the high-temperature heat can be taken away in time, and the purpose of rapid cooling can be achieved more efficiently.

[0051] In specific settings, the second flow rate ranges from 80 lmp to 120 lmp, and the specific flow rate can be any value of 90 lpm, 100 lpm, 110 lpm, 115 lmp and 80 lpm to 120 lp, which ensures the transmission efficiency while not affecting the heat absorption of the coolant. Through the above settings, the entire cooling process can be completed in about 2 hours, which greatly reduces the cooling time and improves the cooling efficiency.

[0052] Combination Figure 2 and Figure 3 As shown, Figure 2 This is a cross-sectional view of a single crystal furnace 10 provided in one embodiment of the present application. Figure 3 A schematic diagram of the flow of the first gas in the single crystal furnace 10 provided in one embodiment of the present application. The present application also provides a waste heat recovery device for implementing the waste heat recovery method described in any of the above embodiments, the waste heat recovery device is installed in the single crystal furnace 10, the single crystal furnace 10 includes a furnace body 100 and a furnace cover 200 covered on the furnace body 100, an isolation flange is provided between the furnace body 100 and the furnace cover 200, and an insulation tube 300 is provided on the inner wall of the furnace body 100. When specifically set, the insulation tube 300 includes an upper insulation body 310, a middle insulation body 320 and a lower insulation body 330 arranged in sequence;

[0053] A reaction crucible 400, a main heater 500 and a cooling assembly 600 are arranged in the insulation cylinder 300. The reaction crucible 400 is used to hold the silicon material mixture. The main heater 500 is arranged on the outer periphery of the crucible. The main heater 500 is used to melt the silicon material in the crucible. The cooling assembly 600 is located on the top of the reaction crucible 400. In the specific setting, the cooling assembly 600 includes a heat exchanger 610 and a guide tube 620 located outside the heat exchanger 610, wherein the heat exchanger 610 can be a water-cooled screen. The bottom of the furnace body 100 is provided with a thermal insulation soft felt 700 and an air outlet 800.

[0054] The waste heat recovery device includes a cooling pipe, a temperature difference power generation mechanism connected to the air outlet 800, and an energy storage device electrically connected to the temperature difference power generation mechanism. The cooling pipe is used to pass a coolant. After the coolant is vaporized into a first gas, it passes through the furnace cover 200, the cooling assembly 600, the reaction crucible 400, the main heater 500, the insulation tube 300 in sequence, and flows along the inner wall of the insulation tube 300 to the insulation soft felt 700 and the air outlet 800.

[0055] In the specific setting, the cooling pipe is set at the throat 210 of the single crystal furnace. Through the above setting, the coolant enters from the throat 210 of the single crystal furnace through the cooling pipe, and the coolant is gasified into the first gas. The more specific flow direction is as follows: it flows through the furnace cover 200, the isolation flange, the heat exchanger 610, the internal vortex of the reaction crucible 400, and then rises along the inner wall of the reaction crucible 400 to enter the heat field, and then flows through the main heater 500, the upper insulation body 310, and then flows down along the inner wall of the upper insulation body 310 to the middle insulation body 320 and the lower insulation body 330, and then flows through the furnace bottom insulation soft felt 700, the cooling low heater 900, and finally flows out from the single crystal furnace 10 to the temperature difference power generation mechanism along the gas outlet 800 and the gas delivery equipment connected to the gas outlet 800. Through the above setting, the coolant can reach each area in the single crystal furnace 10 along the above path to achieve cooling of each area, which is conducive to rapid and thorough cooling of the single crystal furnace 10.

[0056] In specific use, when the coolant enters the single crystal furnace 10 through the cooling pipe, the high temperature in the furnace will vaporize the coolant into a high-temperature and hot first gas, and the coolant is input into the temperature difference power generation mechanism in the form of the first gas, and the temperature difference power generation mechanism is used to convert the heat of the first gas into electrical energy and store it in the energy storage device. It should be emphasized that after the temperature difference power generation mechanism converts the heat into electrical energy and stores it in the energy storage device, the energy storage device can supply power to the single crystal furnace 10, which is used to stabilize various electrical properties such as voltage, and becomes a small part of the power source of the single crystal furnace 10.

[0057] The above-mentioned waste heat recovery device is configured by setting an external cooling pipe for the single crystal furnace 10. The cooling pipe is used to pass a coolant. After the coolant enters the furnace, it will be vaporized into a first gas by the high temperature in the furnace. This vaporization process will absorb a large amount of heat, thereby reducing the furnace temperature of the single crystal furnace 10 and improving the cooling efficiency. The gas outlet 800 is then arranged to be connected to the temperature difference power generation mechanism. The first gas with heat will enter the temperature difference power generation mechanism. The temperature difference power generation mechanism is electrically connected to the energy storage device to convert the high heat of the first gas into electrical energy and store it in the energy storage device, so as to complete the waste heat recovery after the single crystal furnace 10 is shut down and avoid the waste of heat energy.

[0058] In order to more conveniently realize the use of a temperature difference power generation mechanism to convert the high heat of the first gas into electrical energy and store it in an energy storage device, a preferred embodiment is that the temperature difference power generation mechanism includes a first-stage temperature difference chamber, a second-stage temperature difference chamber and a third-stage temperature difference chamber arranged in sequence, and each temperature difference chamber has a high-temperature cavity and a low-temperature cavity that are not connected to each other. In the specific setting, the first-stage temperature difference chamber, the second-stage temperature difference chamber and the third-stage temperature difference chamber are respectively provided with a first isolation plate, a second isolation plate and a third isolation plate to divide each of the above-mentioned temperature difference chambers into two chambers, namely a high-temperature cavity and a low-temperature cavity.

[0059] The high temperature cavity of each temperature difference chamber is connected, and the high temperature cavity is also connected to the air outlet 800 of the single crystal furnace 10. The low temperature cavity of each temperature difference chamber is connected to the external airflow. A thermocouple electrically connected to the energy storage device is arranged in each temperature difference chamber, one end of the thermocouple is arranged in the high temperature cavity, and the other end of the thermocouple is arranged in the low temperature cavity. Through the above arrangement, one end of the thermocouple is the high temperature end, and the other end of the thermocouple is the low temperature end. Due to the obvious temperature difference between the high temperature and the low temperature, the high temperature end of the thermocouple and the low temperature end of the thermocouple will generate an electromotive force, that is, the thermoelectric power generation effect. It should be noted that the use of thermocouples for thermoelectric power generation is a mature technical means, which will not be elaborated in detail here.

[0060] By setting the temperature difference power generation mechanism with three temperature difference chambers, and each temperature difference chamber has a thermocouple, the heat conversion rate is improved, and there is no safety risk in using thermocouples for heat exchange, which is adapted to the current crystal pulling environment. In the specific setting, the high temperature chamber in the first temperature difference chamber is connected to the gas outlet 800 of the single crystal furnace 10, and the first gas flowing out of the gas outlet 800 flows along the high temperature chamber in the first temperature difference chamber through the high temperature chamber in the second temperature difference chamber and the high temperature chamber in the third temperature difference chamber. In this process, the heat of the first gas will be lost. According to experiments, the heat recovery efficiency of the thermocouple in the first temperature difference chamber near the gas outlet 800 is 50%, the heat recovery efficiency of the thermocouple in the second temperature difference chamber is 25%, and the heat recovery efficiency of the thermocouple in the second temperature difference chamber is 10%.

[0061] More specifically, the high temperature chambers in the primary temperature difference chamber, the secondary temperature difference chamber, and the tertiary temperature difference chamber are all connected through connecting pipes. When specifically set, the length of the connecting pipe can be set according to the amount of the first gas, which is not limited here. It should be noted that by setting the length of the connecting pipe, the heat recovery rate of the thermocouples in each temperature difference chamber can be changed. For example, when the length of the connecting pipe is long, the first gas will continue to exchange heat when flowing through the connecting pipe, so that the heat entering the secondary temperature difference chamber is low, and the heat recovery rate will also be reduced.

[0062] In order to better collect the first gas after heat recovery, a storage barrel connected to the high temperature chamber in the three-stage temperature difference chamber can also be set, and the storage barrel is used to collect the first gas. Through the above arrangement, the first gas can be liquefied by pressurization and cooling means and wait for the next cycle, and the separate cooling pipeline also ensures that it is different from the first pipeline for introducing argon gas in the crystal pulling process. When the waste heat recovery device is abnormal, the original cooling process can be converted in time, and no abnormal impact will be caused on the single crystal furnace equipment.

[0063] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A waste heat recovery method, characterized in that: The waste heat recovery method comprises the following steps: S1. During the growth of the crystal in the single crystal furnace, argon gas is introduced through the first pipe. After the growth of the crystal is completed, the introduction of the argon gas is stopped. The single crystal furnace is externally connected to a cooling pipe. The gas outlet of the single crystal furnace is also connected to a temperature difference power generation mechanism, and the temperature difference power generation mechanism is electrically connected to an energy storage device. S2, passing a coolant into the cooling pipe, wherein the coolant vaporizes into a first gas having heat and flows into the temperature difference power generation mechanism; S3. The temperature difference power generation mechanism converts the heat of the first gas into electrical energy and stores it in the energy storage device.

2. The waste heat recovery method according to claim 1, characterized in that: The coolant is any one of liquid nitrogen, liquid helium, liquid carbon dioxide and liquid Freon.

3. The waste heat recovery method according to claim 1, characterized in that: In step S2, the following steps are specifically included: a gas conveying device is provided on the gas outlet, and the gas conveying device inputs the first gas into the temperature difference power generation mechanism.

4. The waste heat recovery method according to claim 3, characterized in that: In step S2, the following steps are also included: S21, after a preset amount of the coolant is introduced into the cooling pipe, the coolant is stopped from being introduced further; S22. After the coolant stops flowing in, the gas delivery device waits for a set time and then inputs the first gas into the temperature difference power generation mechanism at a first flow rate.

5. The waste heat recovery method according to claim 4, characterized in that: The steps S21 and S22 are used as a loop unit and are looped multiple times.

6. The waste heat recovery method according to claim 4, characterized in that: The setting time ranges from 30min to 60min.

7. The waste heat recovery method according to claim 3, characterized in that: In step S2, the following steps are also included: S21, continuously introducing the coolant into the cooling pipe; S22. The gas delivery device continuously inputs the first gas into the temperature difference power generation mechanism at a second flow rate.

8. The waste heat recovery method according to claim 7, characterized in that: The second flow rate ranges from 80 lmp to 120 lmp.

9. A waste heat recovery device for implementing the waste heat recovery method according to any one of claims 1 to 8, characterized in that: The waste heat recovery device is installed in the single crystal furnace: The single crystal furnace comprises a furnace body and a furnace cover arranged on the furnace body, the inner wall of the furnace body is provided with a heat preservation tube, a reaction crucible, a heater and a cooling component are arranged in the heat preservation tube, the heater is arranged on the outer periphery of the crucible, the cooling component is located on the top of the crucible, and a heat preservation soft felt and the gas outlet are arranged at the bottom of the furnace body; The waste heat recovery device includes a cooling pipe, a temperature difference power generation mechanism connected to the air outlet, and an energy storage device electrically connected to the temperature difference power generation mechanism. The cooling pipe is used to pass a coolant. After the coolant is vaporized into a first gas, it passes through the furnace cover, the cooling assembly, the reaction crucible, the heater, the insulation tube in sequence, and flows along the inner wall of the insulation tube to the insulation soft felt and the air outlet.

10. The waste heat recovery device according to claim 9, characterized in that: The temperature difference power generation mechanism comprises a primary temperature difference chamber, a secondary temperature difference chamber and a tertiary temperature difference chamber arranged in sequence, and each temperature difference chamber has a high temperature chamber and a low temperature chamber which are not connected to each other, wherein: The high temperature chambers of each temperature difference chamber are connected, and the high temperature chambers are also connected to the air outlet; The low temperature cavity of each temperature difference chamber is connected to the external air flow; A thermocouple electrically connected to the energy storage device is disposed in each of the temperature difference chambers, one end of the thermocouple is disposed in the high temperature chamber, and the other end of the thermocouple is disposed in the low temperature chamber.

Images