A protective gas recovery system, method and readable storage medium

Abstract

The present invention provides a protective gas recovery system, method and readable storage medium, which belong to the field of gas recovery; it solves the problems of high operating cost and low purity of recovered argon gas in existing silicon carbide coating equipment; technical solution: a protective gas recovery system includes several silicon carbide coating devices, and the multiple silicon carbide coating devices are connected to a first vacuum pump. The first vacuum pump is also connected to a purification treatment system through an H switch valve. The purification treatment system is also connected to a gas detection system through an N switch valve. The gas detection system is also connected to a first air duct, a second air duct and a booster pump. The booster pump is connected to a recovery storage tank. The purification treatment system includes multiple purification treatment devices, each of which is connected to the first air duct through a third valve, and each of which is connected to the second air duct through a fourth valve; the present invention is applied to gas recovery.

Description

Technical Field

[0001] The present invention provides a protective gas recovery system, method and readable storage medium, belonging to the technical field of gas recovery. Background Art

[0002] During operation, silicon carbide coating equipment consumes a large amount of high-purity protective gas to quickly cool the furnace body. The protective gas is mainly high-purity argon. After entering the equipment, the high-purity protective gas absorbs the temperature of the accessories in the furnace, and is then pumped away by the vacuum pump and discharged through the chimney. This treatment method not only causes a large amount of protective gas to be wasted, but also greatly increases the operating cost of silicon carbide coating equipment.

[0003] Based on this, a Chinese invention patent (CN 107298434 A) proposes a two-stage catalytic-adsorption system in an argon recovery device. The exhaust gas is passed into a first catalytic system for a catalytic reaction to obtain a first argon gas. To ensure complete reaction of impurities, excess air is introduced. The first argon gas then passes through the first adsorption system to obtain a second argon gas. The second argon gas is mixed with excess hydrogen and then enters the second catalytic system for a catalytic reaction. The excess oxygen is then converted into water to obtain a third argon gas. The third argon gas enters the second adsorption system to remove the water to obtain a fourth argon gas. The nitrogen and hydrogen contained in the fourth argon gas are then removed by cryogenic distillation. During the use of this system to recover the protective gas, excess air and excess hydrogen need to be introduced and then removed. The operation process is complicated, and it is impossible to determine whether the fourth argon gas after removing nitrogen and hydrogen still contains impurities. If you want to detect whether the argon gas still contains impurities, you need to introduce a gas detection device. However, if the argon gas still contains impurities, the argon gas needs to be reintroduced into the two-stage catalytic-adsorption system for impurity removal and purification. During the re-purification, if the first catalytic system of the two-stage catalytic-adsorption system is directly connected to the exhaust outlet of the operating equipment, it is necessary to adjust the structure of the connection between the first catalytic system and the exhaust outlet of the operating equipment, which is time-consuming and labor-intensive and increases the gas recovery cost.

[0004] Because silicon carbide coating equipment is vacuum thermal equipment, after years of operation, the furnace body, under the dual effects of high temperature and pressure, will experience leakage due to defects such as welds and steel plate pinholes. When the shielding gas is recovered, this water vapor will enter the furnace. In the high temperature environment, the water vapor will chemically react with the graphite products in the heat field, affecting the purity of the recovered shielding gas. The two-stage catalytic-adsorption system in the aforementioned argon recovery device does not consider how to prevent the impact of argon purity caused by small leaks in the furnace welds. Summary of the Invention

[0005] In order to solve the technical problems of high operating costs and low purity of recovered argon gas in existing silicon carbide coating equipment, the present invention proposes a shielding gas recovery system, method and readable storage medium. The purpose is to reduce the operating costs of silicon carbide coating equipment by improving the hardware structure of the shielding gas recovery system or the combined connection of hardware modules and / or circuits, while improving the purity of the shielding gas recovery.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a protective gas recovery system includes a plurality of silicon carbide coating devices, each of which is connected to a first vacuum pump, and a first valve is connected between each silicon carbide coating device and the first vacuum pump;

[0007] The first vacuum pump is further connected to a purification treatment system via an H switch valve, and the purification treatment system is further connected to a gas detection system via an N switch valve. The gas detection system is further connected to a first air channel, a second air channel and a booster pump, and the booster pump is connected to a recovery storage tank;

[0008] The purification treatment system includes a plurality of purification treatment devices, a second valve is provided between each of the purification treatment devices, each purification treatment device is connected to the first airway through a third valve, and each purification treatment device is connected to the second airway through a fourth valve;

[0009] A fifth valve is provided between the gas detection system and the first air channel, a sixth valve is provided between the gas detection system and the second air channel, and a P switch valve is provided between the gas detection system and the booster pump.

[0010] Furthermore, the purification treatment device includes a precision filter, a catalytic system, a condensing device, an adsorption system and an oxygen absorption system. The precision filter, the catalytic system, the condensing device, the adsorption system and the oxygen absorption system are connected in sequence. The precision filter is interconnected with the first vacuum pump, and the oxygen absorption system is interconnected with the gas detection system.

[0011] Furthermore, a recovery gas cache tank is connected between the precision filter and the first vacuum pump, an I switch valve is provided between the recovery gas cache tank and the precision filter, the recovery gas cache tank is connected to the first vacuum pump through the H switch valve, a seventh valve is provided between the recovery gas cache tank and the first air duct, and an eighth valve is provided between the recovery gas cache tank and the second air duct.

[0012] Furthermore, each silicon carbide coating device is connected to a second vacuum pump group, and a ninth valve is provided between the silicon carbide coating device and the second vacuum pump group.

[0013] Furthermore, the control mode of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, the eighth valve, the ninth valve, the H switch valve, the N switch valve, the P switch valve and the I switch valve is manual control and / or electrical control.

[0014] Furthermore, seven silicon carbide coating devices are provided.

[0015] A shielding gas recovery method, using the shielding gas recovery system described above, comprises the following steps:

[0016] Step 1: Open the first valve corresponding to the silicon carbide coating device that needs to discharge the mixed gas, and the mixed gas passes through the recovery gas buffer tank and then enters the purification system for impurity removal and purification to obtain the first argon gas;

[0017] Step 2: Send the first argon gas into a gas detection system for detection. In the gas detection system, detect whether the first argon gas meets the recovery standard. If the first argon gas contains an impurity with an excessive concentration, send the first argon gas into a purification device for treating the impurity to remove the impurities and purify it again. If the first argon gas contains multiple impurities with excessive concentrations, determine the path of impurity removal and purification in the purification system according to the types of impurities with excessive concentrations in the first argon gas, remove the impurities and purify them again in order, and obtain the second argon gas after the further impurity removal and purification.

[0018] The second argon gas is sent to the gas detection system for detection. When it is detected that the second argon gas contains an impurity with an excessive concentration, the second argon gas is sent to a purification device for treating the impurity to remove the impurities and purify it again. When it is detected that the second argon gas still contains multiple impurities with excessive concentrations, the path of impurity removal and purification in the purification system is determined according to the types of impurities with excessive concentrations contained in the second argon gas, and the impurities are removed and purified again in sequence. If it is detected that the second argon gas meets the recovery standard, the second argon gas that meets the recovery standard is sent to the recovery storage tank through a booster pump.

[0019] A readable storage medium stores a computer program, which implements the method steps described above when executed by a processor.

[0020] The present invention has the following beneficial effects compared to the prior art:

[0021] 1. The multiple silicon carbide coating devices of the present invention are respectively connected to the first vacuum pump through the first valve, so that a set of first vacuum pumps can control and recover the mixed gas discharged from the multiple silicon carbide coating devices. The mixed gas discharged from one or more silicon carbide coating devices can be recovered at the same time. During large-scale production, intensive management and control can be achieved in conjunction with the control system;

[0022] 2. The present invention can control the mixed gas to form a feedback loop in the purification system and the gas detection system through the mutual cooperation of the first air channel, the second air channel, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve, and perform multiple gas detections to ensure the purity of the second argon gas finally collected in the recovery storage tank, thereby reducing the operating cost of the silicon carbide coating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings:

[0024] Figure 1 Schematic diagram of the system structure of the present invention;

[0025] In the figure: 1 is a silicon carbide coating device, 2 is a first vacuum pump, 3 is a recovery gas buffer tank, 4 is a first valve, 5 is a second valve, 6 is a third valve, 7 is a fourth valve, 8 is a fifth valve, 9 is a sixth valve, 10 is a seventh valve, 11 is an eighth valve, 12 is a precision filter, 13 is a catalytic system, 14 is a condensing device, 15 is an adsorption system, 16 is an oxygen absorption system, 17 is a gas detection system, 18 is a booster pump, 19 is a recovery storage tank, 20 is a first air duct, 21 is a second air duct, 22 is a second vacuum pump group, 23 is a ninth valve, and 24 is a control system. DETAILED DESCRIPTION

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate relative positions or positional relationships, which are only for the convenience of describing the present invention and simplifying the description, and do 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 limiting the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second" and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0027] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0028] like Figure 1 As shown, the present invention provides a shielding gas recovery system, comprising a control system 24 and several silicon carbide coating devices 1. Each of the multiple silicon carbide coating devices 1 is connected to a first vacuum pump 2, and a first valve 4 is connected between each silicon carbide coating device 1 and the first vacuum pump 2. By using a set of first vacuum pumps 2, multiple silicon carbide coating devices 1 can be used online. During large-scale production, the system 24 can be used to achieve intensive management and control. Because each silicon carbide coating device 1 has a different cooling time, a first valve 4 is connected between each silicon carbide coating device and the first vacuum pump 2. This allows for independent control of shielding gas recovery, meaning that the mixed gas exhausted from one or more silicon carbide coating devices 1 can be recovered simultaneously, providing greater flexibility. Each silicon carbide coating device 1 is also connected to a second vacuum pump assembly 22, with a ninth valve 23 connected between the silicon carbide coating device 1 and the second vacuum pump assembly 22. When the first vacuum pump 2 is not activated for shielding gas recovery, the ninth valve 23 is opened, and the second vacuum pump assembly 22 is activated to extract water vapor generated by infiltration into the silicon carbide coating equipment furnace.

[0029] In this embodiment, seven silicon carbide coating devices 1 and seven first valves 4 are provided, and the seven silicon carbide coating devices 1 correspond to the seven first valves 4 one by one.

[0030] The first vacuum pump 2 is also connected to a recovered gas buffer tank 3 via an H switch valve. The recovered gas buffer tank 3 is also connected to one port of the I switch valve, one port of the seventh valve 10, and one port of the eighth valve 11. The other port of the I switch valve is connected to a purification system, which includes multiple purification devices. A second valve 5 is connected between each of the purification devices. Each purification device is connected to the first airway 20 via a third valve 6, and each purification device is connected to the second airway 21 via a fourth valve 7. The other port of the seventh valve 10 is interconnected with the first airway 20, and the other port of the eighth valve 11 is interconnected with the second airway 21.

[0031] The purification treatment system is also connected to a gas detection system 17 through an N switch valve. The gas detection system 17 is connected to the first air channel 20 through the fifth valve 8. The gas detection system 17 is connected to the second air channel 21 through the sixth valve 9. The gas detection system 17 is connected to the booster pump 18 through the P switch valve. The booster pump 18 is also connected to a recovery storage tank 19. The booster pump 18 and the recovery storage tank 19 interact with each other to recover the mixed gas after the impurity removal treatment, thereby realizing the recovery of the protective gas.

[0032] In this embodiment, five purification treatment devices are provided, namely, a precision filter 12, a catalytic system 13, a condensing device 14, an adsorption system 15, and an oxygen absorption system 16. The precision filter 12, the catalytic system 13, the condensing device 14, the adsorption system 15, and the oxygen absorption system 16 are connected in sequence. Specifically, the precision filter 12 is connected to the recovered gas buffer tank 3 via an I switch valve, and the oxygen absorption system 16 is connected to the gas detection system 17 via an N switch valve.

[0033] The control method of the first valve 4, the second valve 5, the third valve 6, the fourth valve 7, the fifth valve 8, the sixth valve 9, the seventh valve 10, the eighth valve 11, the ninth valve 23, the H switch valve, the N switch valve, the P switch valve and the I switch valve is manual control and / or electrical control.

[0034] The present invention provides a shielding gas recovery method, which uses the shielding gas recovery system described above, and includes the following steps:

[0035] Step 1: Open the first valve 4 corresponding to the silicon carbide coating device 1 from which the mixed gas needs to be discharged. The mixed gas passes through the recovery gas buffer tank 3 and then enters the purification system for impurity removal and purification to obtain the first argon gas.

[0036] Specifically, when the silicon carbide coating device is operating normally, the ninth valve 23 and the second vacuum pump group 22 are normally opened for vacuuming. When high-purity argon gas is introduced into the silicon carbide coating device 1 to cool it down, all valves are closed, and the high-purity argon gas absorbs the heat of the accessories in the silicon carbide coating device. When it is necessary to discharge the mixed gas composed of the argon gas in the silicon carbide coating device 1 and other gases in the furnace, the ninth valve 23 corresponding to the silicon carbide coating device 1 is closed, the corresponding first valve 4 is opened, the first vacuum pump 2 is turned on, the H switch valve and the I switch valve are opened, and the mixed gas enters the precision filter 12 to filter the solid particles it carries. Subsequently, the second valve 5 between the precision filter 12 and the catalytic system 13 is opened, and the mixed gas with the solid particles removed enters the catalytic system 13.

[0037] Since the silicon carbide coating equipment is a vacuum thermal equipment, its furnace body is a double-layer water-cooled structure. When the water pressure in the interlayer of the silicon carbide coating equipment furnace body is 0.3Mpa and the inner cavity is under negative pressure, the water-cooled welds inside the furnace body need to withstand a pressure of 0.4Mpa. After the furnace body has been running for many years, the furnace body is under the dual effects of high temperature and pressure, and the furnace body will leak due to defects such as welds and steel plate sand holes. When the first vacuum pump 2 is not started to recover the mixed gas, the ninth valve 23 is opened and the second vacuum pump group 22 is started to extract the water vapor generated by infiltration in the furnace body; when the mixed gas is recovered, the water vapor will enter the furnace. Under high temperature environment, the water vapor reacts chemically with the graphite products in the hot field to generate H2 (g) and CO (g), which will affect the purity of the recovered mixed gas. The chemical reaction equation is as follows:

[0038] H2O(L)+C(s)→H2(g)+CO(g).

[0039] Therefore, in addition to removing solid particles carried in the mixed gas, H2(g) and CO(g) must also be removed. After the mixed gas with the solid particles removed enters the catalytic system 13, an excess of O2 is introduced. Under the action of high temperature (200-300°C) and a catalyst (solid metal such as palladium or platinum), H2(g) and CO(g) are completely oxidized into H2O and CO2, resulting in a first mixed gas. Therefore, the first mixed gas contains argon, H2O, CO2, and a small amount of oxygen:

[0040] 2H2(g)+O2(g)=2H2O(g) (high temperature, catalyst conditions);

[0041] CO(g)+O2(g)=2CO2(g) (high temperature, catalyst conditions).

[0042] Open the second valve 5 between the catalytic system 13 and the condensing device 14, and send the first mixed gas into the condensing device 14 to condense the gaseous H2O into liquid water. The liquid water is removed through the gas-liquid separator to obtain a second mixed gas, that is, the second mixed gas contains argon, CO2 and a small amount of oxygen.

[0043] Open the second valve 5 between the condensing device 14 and the adsorption system 15, and send the second mixed gas into the adsorption system 15. The adsorption system 15 contains soda lime, which absorbs CO2 to obtain a third mixed gas, that is, the third mixed gas contains argon and a small amount of oxygen.

[0044] Open the second valve 5 between the adsorption system 15 and the oxygen absorption system 16, and send the third mixed gas into the oxygen absorption system 16 to remove oxygen. The oxygen absorption system 16 contains high-temperature getters such as Zr and Ti. Under heating conditions (300-500°C), the high-temperature getters react with oxygen to produce stable metal oxides, thereby removing oxygen from the argon gas to obtain the first argon gas.

[0045] Step 2: Send the first argon gas to the gas detection system 17 for detection. In the gas detection system 17, it is detected whether the first argon gas meets the recovery standard. If the first argon gas contains an impurity with an excessive concentration, the first argon gas is sent to a purification device for treating the impurity to remove the impurities and purify it again. If the first argon gas contains multiple impurities with excessive concentrations, the path of impurity removal and purification in the purification system is determined according to the types of impurities with excessive concentrations in the first argon gas, and the impurities are removed and purified again in order to obtain the second argon gas after the impurity removal and purification again.

[0046] The second argon gas is sent to the gas detection system 17 for detection. When it is detected that the second argon gas contains an impurity with an excessive concentration, the second argon gas is sent to a purification device for treating the impurity to remove the impurities and purify it again. When it is detected that the second argon gas still contains multiple impurities with excessive concentrations, the path of impurity removal and purification in the purification system is determined according to the types of impurities with excessive concentrations contained in the second argon gas, and the impurities are removed and purified again in sequence. If it is detected that the second argon gas meets the recovery standard, the second argon gas that meets the recovery standard is sent to the recovery storage tank 19 through the booster pump 18.

[0047] Specifically, the N switch valve is opened to send the first argon gas into the gas detection system 17. If the first argon gas contains an impurity with a concentration exceeding the standard, the first argon gas is sent to a purification device for treating the impurity to remove the impurities and purify it again. If the first argon gas contains oxygen with a concentration exceeding the standard, the sixth valve 9 and the fourth valve 7 corresponding to the oxygen absorption system 16 are opened, and the first argon gas containing oxygen with a concentration exceeding the standard enters the oxygen absorption system 16 through the second gas channel 21 to absorb oxygen again (the sixth valve 9 is closed when the first argon gas containing oxygen is sent to the oxygen absorption system 16). The first argon gas after the secondary deoxygenation is sent to the gas detection system 17 for re-detection through the first gas channel 20 (if the first argon gas after the secondary deoxygenation directly enters the gas detection system 17 through the N switch valve, it does not need to pass through the first gas channel 20). If the first argon gas meets the recovery standard, the P switch valve is opened and the booster pump 18 is used to send the first argon gas to the recovery storage tank 19.

[0048] If the first argon gas contains multiple impurities with concentrations exceeding the standard, the path of impurity removal and purification in the purification system is determined according to the types of impurities with concentrations exceeding the standard contained in the first argon gas, and the impurities are removed and purified in sequence again. After the impurities are removed and purified again, the second argon gas is obtained. If the first argon gas contains carbon dioxide gas and oxygen with concentrations exceeding the standard, the sixth valve 9 and the fourth valve 7 corresponding to carbon dioxide are opened, and the first argon gas containing carbon dioxide gas and oxygen is first sent to the adsorption system 15 to remove carbon dioxide, and then the second valve 5 between the adsorption system 15 and the oxygen absorption system 16 is opened, and the mixed gas is sent to the oxygen absorption system 16 to remove oxygen (the gas containing When the first argon gas of oxygen is sent to the oxygen absorption system 16, the sixth valve 9 and the fourth valve 7 corresponding to the oxygen absorption system 16 are closed. Then, the third valve 6 and the fifth valve 8 corresponding to the oxygen absorption system 16 are opened (or the N switch valve is directly opened). The first argon gas after the secondary removal of carbon dioxide and oxygen is sent to the gas detection system 17 for re-detection (if the first argon gas after the secondary removal of carbon dioxide and oxygen enters the gas detection system 17 directly through the N switch valve, it does not need to pass through the first air channel 20). If the first argon gas meets the recovery standard, the P switch valve is opened and the booster pump 18 is used to send the first argon gas to the recovery storage tank 19.

[0049] In this embodiment, the first air duct 20 is a channel for the first argon gas to enter the purification treatment system from the gas detection system 17 for further impurity removal and purification, and the second air duct 21 is a channel for the first argon gas after further purification and impurity removal to enter the gas detection system from the purification treatment system, but the present invention is not limited to this. The second air duct 21 can also be a channel for the first argon gas to enter the purification treatment system from the gas detection system 17 for further impurity removal and purification, and the first air duct 20 is a channel for the first argon gas after further purification and impurity removal to enter the gas detection system from the purification treatment system.

[0050] The present invention provides a readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method steps described in the mixed gas recovery method are implemented.

[0051] The protective gas recovery system, method and readable storage medium of the present invention can also be applied to high-temperature purification equipment to recover the mixed gas discharged from the high-temperature purification equipment, and the purification treatment device in the purification treatment system can be adaptively adjusted according to the impurities to be purified.

[0052] Regarding the specific structure of the present invention, it should be noted that the connection relationship between the various component modules adopted in the present invention is definite and feasible. Except for those specifically described in the embodiments, the specific connection relationship can bring about corresponding technical effects and solve the technical problems raised by the present invention without relying on the execution of corresponding software programs. The components, modules, models of specific components appearing in the present invention, the connection methods between each other, and the conventional usage methods and expected technical effects brought about by the above-mentioned technical features, except for those specifically described, all belong to the disclosed contents in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by technical personnel in this field before the application date, or belong to the existing technologies such as conventional technology and common knowledge in this field. There is no need to elaborate, so that the technical solution provided in this case is clear, complete, and feasible, and the corresponding physical products can be reproduced or obtained based on this technical means.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protective gas recovery method based on a protective gas recovery system, characterized in that: The protective gas recovery system comprises a plurality of silicon carbide coating devices (1), each of the plurality of silicon carbide coating devices (1) is connected to a first vacuum pump (2), and a first valve (4) is connected between each silicon carbide coating device (1) and the first vacuum pump (2); The first vacuum pump (2) is further connected to a purification treatment system via an H switch valve, and the purification treatment system is further connected to a gas detection system (17) via an N switch valve. The gas detection system (17) is further connected to a first gas channel (20), a second gas channel (21) and a booster pump (18), and the booster pump (18) is connected to a recovery storage tank (19); The purification treatment system includes a plurality of purification treatment devices, a second valve (5) is provided between each of the purification treatment devices, each purification treatment device is connected to the first airway (20) through a third valve (6), and each purification treatment device is connected to the second airway (21) through a fourth valve (7); A fifth valve (8) is provided between the gas detection system (17) and the first air channel (20), a sixth valve (9) is provided between the gas detection system (17) and the second air channel (21), and a P switch valve is provided between the gas detection system (17) and the booster pump (18); The purification treatment device comprises a precision filter (12), a catalytic system (13), a condensing device (14), an adsorption system (15) and an oxygen absorption system (16), wherein the precision filter (12), the catalytic system (13), the condensing device (14), the adsorption system (15) and the oxygen absorption system (16) are connected in sequence, the precision filter (12) is connected to the first vacuum pump (2), and the oxygen absorption system (16) is connected to the gas detection system (17); A recovered gas buffer tank (3) is further connected between the precision filter (12) and the first vacuum pump (2); an I switch valve is provided between the recovered gas buffer tank (3) and the precision filter (12); the recovered gas buffer tank (3) is connected to the first vacuum pump (2) via the H switch valve; a seventh valve (10) is provided between the recovered gas buffer tank (3) and the first air channel (20); and an eighth valve (11) is provided between the recovered gas buffer tank (3) and the second air channel (21); Each silicon carbide coating device (1) is connected to a second vacuum pump group (22), and a ninth valve (23) is provided between the silicon carbide coating device (1) and the second vacuum pump group (22); The protective gas recovery method based on the protective gas recovery system includes the following steps: Step 1: Open the first valve (4) corresponding to the silicon carbide coating device (1) from which the mixed gas needs to be discharged, and the mixed gas passes through the recovery gas buffer tank (3) and enters the purification system for impurity removal and purification to obtain the first argon gas; Step 2: Send the first argon gas to the gas detection system (17) for detection. In the gas detection system (17), detect whether the first argon gas meets the recovery standard. If the first argon gas contains an impurity with a concentration exceeding the standard, send the first argon gas to a purification device for treating the impurity to remove the impurities and purify it again. If the first argon gas contains multiple impurities with a concentration exceeding the standard, determine the path of impurity removal and purification in the purification system according to the types of impurities with a concentration exceeding the standard contained in the first argon gas, remove the impurities and purify them again in order, and obtain the second argon gas after the impurity removal and purification again. The second argon gas is sent to the gas detection system (17) for detection. When it is detected that the second argon gas contains an impurity with a concentration exceeding the standard, the second argon gas is sent to the purification device for treating the impurity to remove the impurities and purify it again. When it is detected that the second argon gas still contains multiple impurities with a concentration exceeding the standard, the path of the impurity removal and purification in the purification system is determined according to the types of impurities with a concentration exceeding the standard contained in the second argon gas, and the impurities are removed and purified again in sequence. If it is detected that the second argon gas meets the recovery standard, the second argon gas that meets the recovery standard is sent to the recovery storage tank (19) through the booster pump (18).

2. The protective gas recovery method based on the protective gas recovery system according to claim 1, characterized in that: The control mode of the first valve (4), the second valve (5), the third valve (6), the fourth valve (7), the fifth valve (8), the sixth valve (9), the seventh valve (10), the eighth valve (11), the ninth valve (23), the H switch valve, the N switch valve, the P switch valve and the I switch valve is manual control and / or electrical control.

3. The protective gas recovery method based on the protective gas recovery system according to claim 1, characterized in that: The silicon carbide coating devices (1) are provided in seven numbers.

4. A readable storage medium, characterized in that: The readable storage medium stores a computer program, which implements the method steps described in claim 1 when executed by a processor.

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