Heat conduction oil system

Abstract

The heat conduction oil system comprises a heat conduction oil boiler, an oil return pipeline and an auxiliary starting device, the auxiliary starting device comprises a starting tank, the height of the starting tank is higher than the highest point of the oil return pipeline, and the starting tank communicates with the highest point of the oil return pipeline through an oil conveying pipe; the highest point of the oil return pipeline is provided with a first node and a second node in the flowing direction of heat conduction oil in the oil return pipeline, and a first valve for switching connection and disconnection of the oil return pipeline is arranged between the first node and the second node. A second valve arranged on the first oil conveying pipe is configured to switch on-off of the first oil conveying pipe, outlets of the starting tanks are connected with the second node through a second oil conveying pipe, and a third valve arranged on the second oil conveying pipe is configured to switch on-off of the second oil conveying pipe. By means of the heat conduction oil system, heat conduction oil can more easily climb over the highest point of the oil return pipeline, and the starting pressure and the operation pressure of the heat conduction oil system are reduced.

Description

Technical Field

[0001] This application relates to the field of heating technology, and more particularly to a heat transfer oil system. Background Technology

[0002] New energy batteries are being used more and more widely in daily life and industry. For example, new energy vehicles equipped with batteries are already widely used. In addition, batteries are being used more and more in the field of energy storage.

[0003] In battery manufacturing, heating systems capable of stable heating are typically used, and thermal oil systems are a common industrial heating system for this purpose. However, in actual production scenarios, thermal oil systems often experience insufficient starting pressure. Therefore, improving the starting pressure of thermal oil systems is one of the research topics in the industry. Utility Model Content

[0004] To solve the above-mentioned technical problems, this application provides a heat transfer oil system.

[0005] This application is achieved through the following technical solution.

[0006] This application provides a thermal oil system, including a thermal oil boiler for heating thermal oil, a return oil pipeline configured to connect the thermal oil boiler to a heat-using device, and an auxiliary start-up device. The auxiliary start-up device includes a start-up tank, the height of which is higher than the highest point of the return oil pipeline. The start-up tank is connected to the highest point of the return oil pipeline via an oil delivery pipe. Along the flow direction of the thermal oil in the return oil pipeline, the highest point of the return oil pipeline has a first node and a second node. A first valve for switching the on / off state of the return oil pipeline is provided between the first node and the second node. The inlet of the start-up tank is connected to the first node via a first oil delivery pipe. A second valve located on the first oil delivery pipe is configured to switch the on / off state of the first oil delivery pipe. The outlet of the start-up tank is connected to the second node via a second oil delivery pipe. A third valve located on the second oil delivery pipe is configured to switch the on / off state of the second oil delivery pipe.

[0007] Because the auxiliary starting device is located at the highest point of the return oil pipeline, the first valve can switch the on / off state of the return oil pipeline, the second valve can switch the on / off state of the first oil delivery pipeline, and the third valve can switch the on / off state of the second oil delivery pipeline. Therefore, when the heat transfer oil system is started, the second oil delivery pipeline is connected to the return oil pipeline of the heat transfer oil system, and the first valve can keep the return oil pipeline in a conductive state. The gravity of the heat transfer oil in the starting tank and the second oil delivery pipeline increases the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline, making it easier for the heat transfer oil to cross the highest point of the return oil pipeline, reducing the starting pressure and operating pressure of the heat transfer oil system, and also reducing the operating energy consumption of the heat transfer oil system.

[0008] In some embodiments, the auxiliary starting device has a pre-start state; in the pre-start state, the first valve is in a closed state, the return oil line is in a closed state, the second valve and the third valve are in a connected state, and the first oil supply line and the second oil supply line are in a connected state.

[0009] Since the return oil pipeline is closed and the first and second oil pipelines are connected before startup, the heat transfer oil can fill the first and second oil pipelines under gravity and connect to the return oil pipeline through the first and second nodes. This helps to increase the flow pressure of the heat transfer oil in the highest point of the return oil pipeline when it is connected, further reducing the startup pressure of the heat transfer oil system.

[0010] In some embodiments, the auxiliary starting device has a post-start state; in the post-start state, the first valve is in the open state, the return oil line is in the open state, the second valve and the third valve are in the closed state, and the first oil supply line and the second oil supply line are in the closed state.

[0011] Since the return oil pipeline is in the open state and the first and second oil supply pipelines are in the closed state after startup, the heat transfer oil in the heat transfer oil system is already circulating after startup. It does not need to flow through the first oil supply pipeline, the start-up tank and the second oil supply pipeline, which reduces the impact of the auxiliary start-up device on the normal circulation of the heat transfer oil and further reduces the operating pressure of the heat transfer oil system.

[0012] In some embodiments, the auxiliary starting device also has a stop state; in the stop state, the first valve, the second valve and the third valve are in a conducting state, and the return oil line, the first oil supply line and the second oil supply line are in a conducting state.

[0013] Since the return oil line, the first oil supply line, and the second oil supply line are in a conductive state when the system is stopped, the heat transfer oil can refill the first oil supply line and the second oil supply line under the action of gravity when the system is stopped. This prevents air from entering the return oil line through the auxiliary starting device, reduces the risk of heat transfer oil oxidation or water vapor entering the heat transfer oil system, and improves the stability of the heat transfer oil system.

[0014] In some embodiments, the auxiliary starting device includes an oil replenishment pipeline connected to the starting tank, the oil replenishment pipeline is provided with a fourth valve, the fourth valve is used to switch the oil replenishment pipeline on and off, and the starting tank is provided with a level gauge.

[0015] Since the auxiliary starting device includes a replenishment oil pipeline connected to the starting tank, it helps to keep the heat transfer oil level in the starting tank at a position higher than the highest point of the return oil pipeline. This is more conducive to increasing the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline when the return oil pipeline is in a conductive state, and further reduces the starting pressure of the heat transfer oil system.

[0016] In some embodiments, in the pre-start state, the fourth valve is in the open state, and the oil replenishment line is connected to the start-up tank.

[0017] Therefore, in the pre-start state, the first oil supply pipe and the second oil supply pipe are in a conductive state, and the oil replenishment line injects oil into the heat transfer oil system, which can eliminate the need for the oil injection pump of the heat transfer oil system, reduce costs, and simplify the system structure. In addition, in other states, such as the post-start state and the stop state, since the heat transfer oil in the auxiliary starting device does not participate in the circulation of heat transfer oil in the heat transfer oil system, the fourth valve can be in a closed state, and the oil replenishment line does not replenish oil to the auxiliary starting device.

[0018] In some embodiments, the auxiliary starting device further includes an overflow branch, which includes an overflow tank connected to the starting tank, the overflow tank being used to receive heat transfer oil overflowing from the starting tank.

[0019] Since the overflow branch includes an overflow tank connected to the starter tank, it helps the starter tank maintain a liquid level higher than the highest point of the return oil pipeline. The heat transfer oil expands to a certain extent after heating, which can reduce the risk of overflow caused by excessive liquid level and improve the stability of the heat transfer oil system. It also prevents the starter tank from overpressure, further improving the stability of the heat transfer oil system.

[0020] In some embodiments, in the overflow branch, a flow stabilizer is disposed between the starter tank and the overflow tank, and a safety valve is disposed between the flow stabilizer and the starter tank. The safety valve is used to discharge gas from the heat transfer oil system.

[0021] Therefore, the safety valve installed in the overflow branch can release the pressure in the start-up tank and discharge gases in the heat transfer oil system, such as air, nitrogen, water vapor, light components of the heat transfer oil, and low-boiling substances, thereby improving the reliability of the heat transfer oil system.

[0022] In some embodiments, a nitrogen source is connected to the start-up tank via a pipeline.

[0023] Since the nitrogen source is connected to the start-up tank through a pipeline, nitrogen can be used to cover the heat transfer oil inside the start-up tank, preventing the heat transfer oil from coming into contact with air, reducing the risk of heat transfer oil oxidation or water vapor entering the heat transfer oil system, and also reducing the evaporation loss of heat transfer oil to a certain extent, avoiding the risk of environmental pollution. At the same time, it can also reduce the risk of explosion in the confined space of the container.

[0024] In some embodiments, the return oil pipeline has multiple highest points of equal height, and along the flow direction of the heat transfer oil in the return oil pipeline, the auxiliary starting device is located at the highest point closest to the heat transfer oil boiler.

[0025] Since the auxiliary start-up device is located at the highest point closest to the thermal oil boiler, it can easily discharge the gas in the long return oil pipeline on the side of the heat-using equipment, while reducing the mechanical energy loss of the thermal oil in the process.

[0026] In some embodiments, the first valve, the second valve, and the third valve are an integrated valve assembly.

[0027] This reduces the number of pipeline connections and simplifies the pipeline of the auxiliary starting device. At the same time, the integrated valve assembly also facilitates the switching of multiple valve states and improves the operation speed of valve switching.

[0028] In some embodiments, the return oil pipeline connecting the heat-using equipment and the auxiliary starting device is inclined at an upward slope along the flow direction of the heat transfer oil in the return oil pipeline.

[0029] Therefore, the return oil pipeline can traverse undulating terrain and better adapt to the actual installation environment; in addition, when oil is injected into the return oil pipeline, it can better push the gas in the return oil pipeline to move towards the highest point of the system, which is beneficial for the exhaust of the heat transfer oil system.

[0030] In some embodiments, the auxiliary starting device also has a shutdown state; in the shutdown state, the first valve is in a closed state, the second valve and the third valve are in a conducting state, the return oil line is in a closed state, and the first oil supply line and the second oil supply line are in a conducting state.

[0031] Therefore, when the machine is stopped, the return oil pipeline is closed, the heat transfer oil in the heat transfer oil system stops circulating, and the first oil supply pipe and the second oil supply pipe are in a conductive state, so that the auxiliary starting device is connected to the return oil pipeline, which makes it easier for the heat transfer oil system to maintain positive pressure, improves the stability of the heat transfer oil system, and also facilitates the restart of the heat transfer oil system.

[0032] The beneficial effects of this disclosure include: by using this application, the flow pressure of heat transfer oil in the highest point section of the return oil pipeline can be increased, making it easier for the heat transfer oil to cross the highest point of the return oil pipeline, which reduces both the start-up pressure and operating pressure of the heat transfer oil system, and also reduces the operating energy consumption of the heat transfer oil system. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 This is a schematic diagram of the structure of a heat transfer oil system provided in some embodiments of this application;

[0035] Figure 2 This is a schematic diagram of the structure of an auxiliary starting device provided in some embodiments of this application.

[0036] Explanation of reference numerals in the attached figures

[0037] 1-Heat transfer oil system, 1A-Heating section, 1B-Heat application section, 2-Functional unit, 3-Heat transfer oil boiler, 4-Return oil pipeline, 5-Highest point of return oil pipeline, 5A-First node, 5B-Second node, 6-Circulating pump, 7-High-level oil tank, 8-Low-level oil tank, 9-Heat application equipment, 10-Auxiliary starting device, 11-First valve, 12-Second valve, 13-Third valve, 14-Fourth valve, 15-Fifth valve, 16-Starting tank, 16A-Level gauge, 17-First oil supply pipeline, 18-Second oil supply pipeline, 19-Maintenance oil pipeline, 20-Nitrogen source, 21-Overflow tank, 22-Stabilizing tank, 23-Safety valve, 24-First pressure reducing valve, 25-Second pressure reducing valve. Detailed Implementation

[0038] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having”, and any variations thereof, in the specification and the foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0040] In the description of the embodiments of this application, the technical terms "first," "second," "third," "fourth," "fifth," etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0043] In the description of the embodiments of this application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0044] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0045] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0046] The following is a detailed description of this application.

[0047] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0048] In battery manufacturing, heating systems capable of stable heating are typically used. Thermal oil systems are a commonly used industrial heating system for stable heating. Compared to steam heating systems, they offer advantages such as high heat transfer efficiency, strong thermal stability, and low operating costs, and are widely used in industrial heating systems requiring strict temperature control, such as in battery manufacturing.

[0049] Because the operating temperature of heat transfer oil is usually higher than its flash point, it poses certain risks during operation and requires strict control of flow rate and pressure. Therefore, heat transfer oil systems typically employ a high-level oil tank combined with a circulating pump to ensure stable oil supply pressure and flow rate.

[0050] Height of the high-level heat transfer oil tank: H0 = H1 + H2 + H3 + H4;

[0051] H1—Net Positive Suction Head (NPSH) of the circulating pump, in meters;

[0052] H2—Resistance of supply and return oil pipelines and fittings, in meters;

[0053] H3—Elevation difference between the end oil consumption point and the oil supply outlet of the thermal oil boiler, in meters;

[0054] H4—Excess pressure, in meters (m). H4 is usually taken as a constant of 0.5m.

[0055] In actual production scenarios, when the pipelines of the heat transfer oil system need to be raised to higher elevations, if the elevation difference H5 between the highest point of the elevation rises and the oil supply outlet of the heat transfer oil boiler is greater than H0, the heat transfer oil system will not have sufficient pressure to rise above the highest point of the pipeline. Increasing the height of the elevated oil tank will increase the operating pressure and energy loss of the entire system. Therefore, how to increase the starting pressure of the heat transfer oil system is one of the research and development topics in the industry.

[0056] Through research and design, an auxiliary starting device is installed at the highest point of the return oil pipeline of the heat transfer oil system. The gravity of the heat transfer oil in the auxiliary starting device can increase the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline, making it easier for the heat transfer oil to cross the highest point of the return oil pipeline and reducing the starting pressure of the heat transfer oil system.

[0057] Based on this design concept, this application designs a thermal oil system, including a thermal oil boiler for heating thermal oil, a return oil pipeline configured to connect the thermal oil boiler and the heat-using equipment, and an auxiliary starting device including a starting tank. The height of the starting tank is higher than the highest point of the return oil pipeline, and the starting tank is connected to the highest point of the return oil pipeline through an oil supply pipe. Along the flow direction of the thermal oil in the return oil pipeline, the highest point of the return oil pipeline has a first node and a second node. A first valve for switching the on / off state of the return oil pipeline is provided between the first node and the second node. The inlet of the starting tank is connected to the return oil pipeline through a first oil supply pipe. A second valve located on the first oil supply pipe is configured to switch the on / off state of the first oil supply pipe. The outlet of the starting tank is connected to the return oil pipeline through a second oil supply pipe. A third valve located on the second oil supply pipe is configured to switch the on / off state of the second oil supply pipe.

[0058] Because the auxiliary starting device is located at the highest point of the return oil pipeline, the first valve can switch the on / off state of the return oil pipeline, the second valve can switch the on / off state of the first oil delivery pipeline, and the third valve can switch the on / off state of the second oil delivery pipeline. Therefore, when the heat transfer oil system is started, the second oil delivery pipeline is connected to the return oil pipeline of the heat transfer oil system, and the first valve can keep the return oil pipeline in a conductive state. The gravity of the heat transfer oil in the starting tank and the second oil delivery pipeline increases the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline, making it easier for the heat transfer oil to cross the highest point of the return oil pipeline, reducing the starting pressure and operating pressure of the heat transfer oil system, and also reducing the operating energy consumption of the heat transfer oil system.

[0059] Below, refer to Figures 1 to 2 Some embodiments of this application will be described in detail.

[0060] Figure 1 This is a schematic diagram of the structure of a heat transfer oil system provided in some embodiments of this application; Figure 2 This is a schematic diagram of the structure of an auxiliary starting device provided in some embodiments of this application.

[0061] A first aspect of this application provides a heat transfer oil system 1, including a heat transfer oil boiler 3 for heating heat transfer oil, a return oil pipeline 4 configured to connect the heat transfer oil boiler 3 and a heat-using device 9, and an auxiliary start-up device 10 including a start-up tank 16, the height of which is higher than the highest point 5 of the return oil pipeline, and the start-up tank 16 being connected to the highest point 5 of the return oil pipeline via an oil delivery pipe; along the flow direction of the heat transfer oil in the return oil pipeline 4, the highest point 5 of the return oil pipeline has a first A first valve 11 is provided between node 5A and the second node 5B, and between the first node 5A and the second node 5B, to switch the on / off state of the return oil pipeline 4. The inlet of the starter tank 16 is connected to the return oil pipeline 4 through the first oil supply pipeline 17. The second valve 12 provided on the first oil supply pipeline 17 is configured to switch the on / off state of the first oil supply pipeline 17. The outlet of the starter tank 16 is connected to the return oil pipeline 4 through the second oil supply pipeline 18. The third valve 13 provided on the second oil supply pipeline 18 is configured to switch the on / off state of the second oil supply pipeline 18.

[0062] In the embodiments of this application, the heat transfer oil system 1, namely the heat transfer oil heating furnace system, refers to a system in which heat transfer oil is heated by a heating furnace and then subjected to forced circulation to exchange heat with crude oil, natural gas or other media passing through a heat exchanger.

[0063] In the embodiments of this application, the heat transfer oil is an organic heat carrier used for indirect heat transfer. In the embodiments of this application, the heat transfer oil can be an alkylbenzene type heat transfer oil or a mineral type heat transfer oil, and this application does not limit it.

[0064] In the embodiments of this application, the thermal oil boiler 3 refers to a heater, the heat carrier of which is thermal oil, and the thermal oil boiler 3 is disposed in the heating part 1A of the thermal oil system 1.

[0065] Optionally, the thermal oil boiler 3 can be an electric heating boiler, a coal-fired boiler, or a gas-fired boiler; this application does not limit this.

[0066] Alternatively, the number of thermal oil boilers 3 can be one or more. When there are multiple boilers, a spare thermal oil boiler 3 can be set up for use during maintenance or rotation.

[0067] In the embodiments of this application, the return oil pipeline 4 is a pipeline that guides the flow of heat transfer oil between the hot oil boiler 3 and the heat-using part 1B of the heat transfer oil system 1, and the flow direction of the heat transfer oil in the return oil pipeline 4 is from the heat-using part 1B to the heat transfer oil boiler 3.

[0068] In the embodiments of this application, the return oil pipeline 4 has a certain slope to facilitate crossing the functional unit 2 outside the heat transfer oil system 1. This application does not limit the range of the slope of the return oil pipeline 4.

[0069] For example, such as Figure 1As shown, functional unit 2 can be a factory, living area, laboratory or other area where the return oil pipeline 4 is not allowed to pass through. The return oil pipeline 4 has a certain slope and can extend from above the functional unit 2 and cross over it.

[0070] In the embodiments of this application, it can be understood that the upper part of the functional unit 2 refers to the side of the functional unit 2 opposite to the direction of gravity, the height refers to the length along the direction of gravity, and the highest point 5 of the return oil pipeline refers to the section of the return oil pipeline 4 that is farthest from the installation surface of the heat transfer oil system 1 along the direction of gravity.

[0071] For example, such as Figure 1 As shown, the shape of the return oil line 4 can be over the functional unit 2. Of course, those skilled in the art should understand that the slope of the return oil line 4 can be adjusted according to the height of the functional unit 2 and the actual installation position, and is not limited to the situation shown in the figure.

[0072] Optionally, the heat transfer oil system 1 may have only one highest point 5 of the return oil pipeline, or it may have multiple highest points 5 of the return oil pipelines at the same height.

[0073] In the embodiments of this application, the heat-using device 9 refers to the device within the heat-using part 1B, which may be a heat exchanger or other heat-requiring devices connected to the heat exchanger. This application does not limit this.

[0074] In the embodiments of this application, it can be understood that, for circulating heat transfer oil, the heat transfer oil system 1 may be equipped with a circulating pump 6 in the heating section 1A. In this application, the circulating pump 6 refers to the pump used to transport the circulating liquid for reaction, absorption, separation, and absorption liquid regeneration in the system.

[0075] Optionally, the circulating pump 6 can be installed on the inlet pipe side of the thermal oil boiler 3 and connected in series with the thermal oil boiler 3. Of course, the circulating pump 6 can also be installed at other locations in the heating section 1A.

[0076] Optionally, the number of circulating pumps 6 can be one or more. When there are multiple circulating pumps, a spare circulating pump 6 can be set up for use during maintenance or rotation.

[0077] For example, the type of circulating pump 6 can be a centrifugal pump, screw pump, gear pump, etc. This application does not limit this.

[0078] In the embodiments of this application, such as Figure 1 As shown, the heating unit 1A can also be equipped with a high-level oil tank and a low-level oil tank 8, both of which are connected to the thermal oil boiler 3 through pipelines.

[0079] It is understandable that the installation height of the high-level oil tank is higher than that of the low-level oil tank 8.

[0080] For example, the low-level oil tank 8 can be an oil storage tank, which is placed horizontally. The volume of the low-level oil tank 8 should be able to receive the heat transfer oil in the largest isolation space of the system and the appropriate amount of replenishment required by the system.

[0081] For example, the low-level oil tank 8 can be installed at the lowest position of the heat transfer oil system 1, which is beneficial for the heat transfer oil in the system to return to the low-level oil tank 8 when the heat transfer oil system 1 stops working.

[0082] Optionally, the low-level oil tank 8 can be equipped with a vent pipe, a breather valve, or other venting devices.

[0083] For example, the height of the elevated oil tank can be calculated using the following formula:

[0084] Height of the elevated oil tank: H0 = H1 + H2 + H3 + H4;

[0085] H1—Net Positive Suction Head (NPSH) of Circulating Pump 6, in meters;

[0086] H2—Resistance of supply and return oil pipelines and fittings, in meters;

[0087] H3—Elevation difference between the end oil supply point and the oil supply outlet of thermal oil boiler 3, in meters;

[0088] H4—Excess pressure, in meters (m). H4 is usually taken as a constant of 0.5m.

[0089] Optionally, the high-level oil tank can be an expansion tank or expansion vessel, used to store the total amount of heat transfer oil that expands after being heated from room temperature to operating temperature.

[0090] Optionally, the high-level oil tank may also be equipped with a liquid level (low level, high level) alarm device, etc., but this application does not limit this.

[0091] In the embodiments of this application, such as Figure 2 As shown, the auxiliary starting device 10 includes a starting tank 16. The height of the starting tank 16 is higher than the highest point 5 of the return oil pipeline. The starting tank 16 is connected to the highest point 5 of the return oil pipeline through the oil supply pipeline.

[0092] Optionally, the starter tank 16 is a pressure vessel capable of withstanding a certain pressure and storing liquid.

[0093] For example, such as Figure 2 As shown, the starter tank 16 can be equipped with a monitoring device, such as a level gauge 16A, to monitor the liquid level in the starter tank 16 when storing liquid.

[0094] It is understandable that the height of the starting tank 16 is higher than the highest point 5 of the return oil pipeline, meaning that when storing liquid, the liquid level in the starting tank 16 is also higher than the highest point 5 of the return oil pipeline.

[0095] In the embodiments of this application, such as Figure 1 , Figure 2 As shown, along the flow direction of the heat transfer oil in the return oil pipeline 4, the highest point 5 of the return oil pipeline has a first node 5A and a second node 5B. A first valve 11 is provided between the first node 5A and the second node 5B to switch the on / off state of the return oil pipeline 4.

[0096] Optionally, the first valve 11 can be a gate valve, a globe valve, a butterfly valve, a solenoid valve, or other valves, and this application does not limit this.

[0097] In the embodiments of this application, such as Figure 2 As shown, the inlet of the starting tank 16 is connected to the first node 5A of the return oil pipeline 4 through the first oil supply pipe 17. The second valve 12 located on the first oil supply pipe 17 is configured to switch the on / off state of the first oil supply pipe 17. The outlet of the starting tank 16 is connected to the second node 5B of the return oil pipeline 4 through the second oil supply pipe 18. The third valve 13 located on the second oil supply pipe 18 is configured to switch the on / off state of the second oil supply pipe 18.

[0098] This application embodiment does not limit the shape and size of the inlet and outlet of the starting tank 16. Their structures can be the same or different. It is understood that the only difference may be their location.

[0099] Optionally, the second valve 12 can be a gate valve, a globe valve, a butterfly valve, a solenoid valve, or other valves, and this application does not limit this.

[0100] Optionally, the third valve 13 can be a gate valve, a globe valve, a butterfly valve, a solenoid valve, or other valves, and this application does not limit this.

[0101] Alternatively, the first valve 11, the second valve 12, and the third valve 13 may be of the same type or different types. This application does not impose any restrictions on this.

[0102] In the embodiments of this application, the first valve 11, the second valve 12, and the third valve 13 are valves that can independently switch states.

[0103] Since the auxiliary starting device 10 is located at the highest point of the return oil pipeline 4, the first valve 11 can switch the on / off state of the return oil pipeline 4, the second valve 12 can switch the on / off state of the first oil supply pipeline 17, and the third valve 13 can switch the on / off state of the second oil supply pipeline 18. Therefore, when the heat transfer oil system 1 is started, the second oil supply pipeline 18 is connected to the return oil pipeline 4 of the heat transfer oil system 1, and the first valve 11 can keep the return oil pipeline 4 in a conductive state. The gravity of the heat transfer oil in the starting tank 16 and the second oil supply pipeline 18 increases the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline 4, making it easier for the heat transfer oil to cross the highest point 5 of the return oil pipeline, reducing the starting pressure and operating pressure of the heat transfer oil system 1, and also reducing the operating energy consumption of the heat transfer oil system 1.

[0104] In the embodiments of this application, the auxiliary starting device 10 has a pre-start state; in the pre-start state, the first valve 11 is in the closed state, the return oil line 4 is in the closed state, the second valve 12 and the third valve 13 are in the open state, and the first oil supply line 17 and the second oil supply line 18 are in the open state.

[0105] For example, when the auxiliary start-up device 10 is in the pre-start state, the heat transfer oil system 1 is also not started, and the circulating pump 6 is not in the conducting state.

[0106] Since the return oil pipeline 4 is in the off state before startup, and the first oil pipeline 17 and the second oil pipeline 18 are in the conducting state, the heat transfer oil can fill the first oil pipeline 17 and the second oil pipeline 18 under the action of gravity before startup, and connect with the return oil pipeline 4 through the first node 5A and the second node 5B. This is beneficial to increase the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline 4 when the return oil pipeline 4 is in the conducting state, and further reduces the startup pressure of the heat transfer oil system 1.

[0107] In the embodiments of this application, the auxiliary starting device 10 has a post-start state; in the post-start state, the first valve 11 is in the open state, the return oil line 4 is in the open state, the second valve 12 and the third valve 13 are in the closed state, and the first oil supply line 17 and the second oil supply line 18 are in the closed state.

[0108] For example, when the auxiliary start-up device 10 is in the start-up state, the heat transfer oil system 1 is in the start-up state, and the circulating pump 6 is operating normally.

[0109] For example, when the auxiliary starting device 10 changes from the pre-start state to the post-start state, the state of the circulating pump 6 of the heat transfer oil system 1 changes from off to on.

[0110] Since the return oil line 4 is in the open state after startup, and the first oil supply line 17 and the second oil supply line 18 are in the closed state, the heat transfer oil in the heat transfer oil system 1 is already circulating after startup. It does not need to flow through the first oil supply line 17, the start-up tank 16 and the second oil supply line 18, which reduces the impact of the auxiliary start-up device 10 on the normal circulation of the heat transfer oil and further reduces the operating pressure of the heat transfer oil system 1.

[0111] In the embodiments of this application, the auxiliary starting device 10 also has a stop state; in the stop state, the first valve 11, the second valve 12 and the third valve 13 are in the conducting state, and the return oil line 4, the first oil supply line 17 and the second oil supply line 18 are in the conducting state.

[0112] For example, when the auxiliary start-up device 10 changes from the start-up state to the stop state, the circulating pump 6 of the heat transfer oil system 1 stops working.

[0113] Since the return oil line 4, the first oil supply line 17, and the second oil supply line 18 are in a conductive state when the system is stopped, the heat transfer oil can be refilled by gravity in the stopped state. This prevents air from entering the return oil line 4 through the auxiliary starting device 10, reduces the risk of heat transfer oil oxidation or water vapor entering the heat transfer oil system 1, and improves the stability of the heat transfer oil system 1.

[0114] In the embodiments of this application, the auxiliary starting device 10 includes an oil replenishment line 19 connected to the starting tank 16. The oil replenishment line 19 is provided with a fourth valve 14, which is used to switch the on / off state of the oil replenishment line 19. The starting tank 16 is provided with a level gauge 16A.

[0115] For example, such as Figure 2 As shown, the oil replenishment line 19 is connected to the starter tank 16 and can inject oil into the starter tank 16.

[0116] Optionally, the oil replenishment line 19 can inject oil into the starter tank 16 through other oil trucks or oil tanks outside the heat transfer oil system 1.

[0117] Since the auxiliary starting device 10 includes a replenishing oil pipeline 19 connected to the starting tank 16, it is beneficial to keep the liquid level of the heat transfer oil in the starting tank 16 above the highest point 5 of the return oil pipeline. This is more conducive to increasing the flow pressure of the heat transfer oil in the highest point section of the return oil pipeline 4 when the return oil pipeline 4 is in the conducting state, and further reducing the starting pressure of the heat transfer oil system 1.

[0118] In the embodiments of this application, in the pre-start state, the fourth valve 14 is in the conducting state, and the oil replenishment pipeline 19 is connected to the start-up tank 16.

[0119] For example, in the pre-start state, the first oil supply pipe 17 and the second oil supply pipe 18 are in a conductive state, and the oil replenishment pipe 19 injects oil into the heat transfer oil system 1, which can eliminate the need for the oil injection pump of the heat transfer oil system 1, reduce the oil injection cost, and simplify the system structure.

[0120] Optionally, in other states, such as the start-up state and the stop state, since the heat transfer oil in the auxiliary start-up device 10 does not participate in the circulation of the heat transfer oil in the heat transfer oil system 1, the fourth valve 14 can be in the closed state, and the oil replenishment line 19 does not replenish the auxiliary start-up device 10.

[0121] In the embodiments of this application, the auxiliary starting device 10 also has a shutdown state; in the shutdown state, the first valve 11 is in the closed state, the second valve 12 and the third valve 13 are in the open state, the return oil line 4 is in the closed state, and the first oil supply line 17 and the second oil supply line 18 are in the open state.

[0122] For example, the auxiliary starting device 10 can switch from a stopped state to a stopped state, and the first valve can switch from being open to being closed.

[0123] Therefore, when the system is shut down, the heat transfer oil system 1 stops, the return oil pipeline 4 is closed, the heat transfer oil in the heat transfer oil system 1 stops circulating, and the first oil pipeline 17 and the second oil pipeline 18 are in a conductive state, so that the auxiliary starting device 10 is connected to the return oil pipeline 4, which makes it easier for the heat transfer oil system 1 to maintain positive pressure, improves the stability of the heat transfer oil system 1, and also makes it easier for the heat transfer oil system 1 to be restarted.

[0124] In the embodiments of this application, the auxiliary starting device 10 further includes an overflow branch, which includes an overflow tank 21 connected to the starting tank 16. The overflow tank 21 is used to receive the heat transfer oil overflowing from the starting tank 16.

[0125] Optionally, the overflow tank 21 is connected to the start-up tank 16, and the overflowing heat transfer oil enters the overflow tank 21 through a pipeline.

[0126] For example, in the pre-start state, the oil replenishment line 19 fills the starter tank 16 with oil, and the overflowing heat transfer oil enters the overflow tank 21.

[0127] Optionally, a fifth valve 15 can be set to control the connection between the overflow tank 21 and the start-up tank 16.

[0128] For example, the fifth valve 15 can be a gate valve, a globe valve, a butterfly valve, a solenoid valve, etc., and this application does not limit it.

[0129] Optionally, the overflow tank 21 may also be equipped with an exhaust valve to release internal pressure.

[0130] Since the overflow branch includes an overflow tank 21 connected to the starter tank 16, it helps the starter tank 16 to maintain the liquid level above the highest point 5 of the return oil pipeline. In addition, the heat transfer oil has a certain amount of expansion after heating, and the overflow tank 21 can reduce the risk of overflow caused by the liquid level in the starter tank 16 being too high, thus improving the stability of the heat transfer oil system 1.

[0131] In the embodiments of this application, in the overflow branch, the flow stabilizer tank 22 is disposed between the starter tank 16 and the overflow tank 21, and the safety valve 23 is disposed between the flow stabilizer tank 22 and the starter tank 16. The safety valve 23 is used to discharge the gas in the heat transfer oil system 1.

[0132] For example, in the pre-start state, the auxiliary starting device 10 is positioned higher than the highest point 5 of the return oil pipeline, and the safety valve 23 can discharge gases such as air, water vapor, light components of the heat transfer oil, and low-boiling substances from the heat transfer oil system 1, thereby improving the reliability of the heat transfer oil system 1. This application does not limit the method for venting and dehydrating the heat transfer oil system 1.

[0133] Optionally, a first pressure reducing valve 24 is provided between the flow stabilizing tank 22 and the starting tank 16.

[0134] For example, in the post-start state, the flow stabilizing tank 22 is connected to the starting tank 16 via the first pressure reducing valve 24. Since the oil replenishment line 19 can no longer replenish oil in the post-start state, when the internal pressure of the starting tank 16 is insufficient or the liquid level drops, heat transfer oil can be replenished to the starting tank 16 through the flow stabilizing tank 22 and the first pressure reducing valve 24 to maintain the liquid level at a predetermined position, reducing the risk of gas entering the return oil pipeline or the heat transfer oil system 1. In addition, the first pressure reducing valve 24 can reduce the pressure of the heat transfer oil flow, facilitating regulation.

[0135] Optionally, a flow regulating valve or other components may be installed between the flow stabilizing tank 22 and the starting tank 16; this application does not limit this.

[0136] Optionally, the flow stabilizing tank 22 may be equipped with one or more vent valves, and vent valves may be installed at both the top and bottom of the flow stabilizing tank 22 to release pressurized gas and liquid inside the tank.

[0137] In embodiments of this application, the first pressure-reducing valve 24 may be connected in parallel with the fifth valve 15.

[0138] For example, in the pre-start state, the oil replenishment line 19 fills the starter tank 16 with oil, and the fifth valve 15 is opened to connect the overflow tank 21 with the starter tank 16. The overflowing heat transfer oil enters the overflow tank 21 through the fifth valve 15 and the flow stabilizer 22. It can be understood that after detecting the flow of heat transfer oil into the overflow tank 21, the fourth valve 14 can be closed to stop the oil replenishment from the oil replenishment line 19.

[0139] For example, after startup, the fifth valve 15 is closed, and the flow stabilizing tank 22 is connected to the starting tank 16 through the pipeline where the first pressure reducing valve 24 and the safety valve 23 are located, so as to achieve vapor-liquid balance in the overflow branch.

[0140] Therefore, the safety valve 23 installed in the overflow branch can release the pressure in the starter tank 16 and discharge gases such as air, nitrogen, water vapor, light components of heat transfer oil, and low-boiling substances from the heat transfer oil system 1, thereby improving the reliability of the heat transfer oil system 1.

[0141] In the embodiments of this application, such as Figure 2 As shown, nitrogen source 20 is connected to starter tank 16 via a pipeline.

[0142] Optionally, a second pressure reducing valve 25 and a shut-off valve for controlling the on / off state are installed on the pipeline connecting the nitrogen source 20 to the starter tank 16.

[0143] Alternatively, one or more of the aforementioned shut-off valves may be installed.

[0144] For example, in the pre-start state, after the gas is discharged, the nitrogen source 20 is turned on to continuously introduce nitrogen into the starter tank 16.

[0145] Since the nitrogen source 20 is connected to the start-up tank 16 via a pipeline, nitrogen can be used to cover the heat transfer oil inside the start-up tank 16, preventing the heat transfer oil from contacting air and reducing the risk of oxidation or water vapor entering the heat transfer oil system 1. It can also reduce evaporation loss of the heat transfer oil to some extent, avoiding environmental pollution risks, and further reducing the risk of explosion within the confined space of the container. In addition, the nitrogen source 20 can also be used for fire extinguishing, improving the reliability of the heat transfer oil system 1.

[0146] In the embodiments of this application, the return oil pipeline 4 has multiple highest points 5 of the same height. Along the flow direction of the heat transfer oil in the return oil pipeline 4, the auxiliary starting device 10 is set at the highest point closest to the heat transfer oil boiler 3.

[0147] For example, the highest point 5 of the return oil pipeline is a long pipe section, and the auxiliary start-up device 10 can be set in the pipe section closest to the thermal oil boiler 3.

[0148] As another example, the heat transfer oil system 1 can traverse multiple functional units 2, and the highest point 5 of multiple return oil pipelines at the same height, and the auxiliary start-up device 10 can be set at the highest point closest to the heat transfer oil boiler 3.

[0149] Since the auxiliary start-up device 10 is located at the highest point closest to the thermal oil boiler 3, it is easy to discharge the gas in the long return oil pipeline 4 of the heat-using section 1B, while reducing the mechanical energy loss of the thermal oil in the process.

[0150] In the embodiments of this application, the first valve 11, the second valve 12, and the third valve 13 are integrated valve assemblies.

[0151] This reduces the number of pipe connections and simplifies the piping of the auxiliary starter 10. At the same time, the integrated valve assembly also facilitates switching the status of multiple valves and improves the operation speed of switching valves.

[0152] In the embodiments of this application, the return oil pipeline 4, which connects the heat transfer oil in the return oil pipeline 4, is inclined at an upward slope along the flow direction of the heat transfer oil in the return oil pipeline 4.

[0153] It is understandable that the upward slope of the above-mentioned pipe section in the return oil pipeline 4 can be adjusted according to the actual application environment, and this application does not limit it.

[0154] Therefore, the return oil pipeline 4 can traverse undulating terrain, such as over functional unit 2, and better adapt to the actual installation environment; in addition, when oil is injected into the return oil pipeline 4, it can better push the gas in the return oil pipeline 4 upward along the pipeline and move towards the highest point of the system, which is beneficial for the exhaust of the heat transfer oil system 1.

[0155] The second aspect of this application discloses an auxiliary start-up method for a heat transfer oil system 1, comprising the following steps:

[0156] Preparation steps: Exhaust and fill the heat transfer oil system 1; the auxiliary starting device 10 is in the pre-start state, the first valve 11 is in the closed state, and the second valve 12, the third valve 13, the fourth valve 14 and the fifth valve 15 are all in the open state. The oil replenishment pipeline 19 fills the starting tank 16 with oil until the overflow tank 21 is detected and the fourth valve 14 is closed.

[0157] Start-up steps: Circulation pump 6 starts, auxiliary start-up device 10 is in the pre-start state, first valve 11 switches from closed state to open state, second valve 12 and third valve 13 both switch from open state to closed state, fifth valve 15 is in the open state, heat transfer oil circulates in heat transfer oil system 1, and heat transfer oil boiler 3 heats heat transfer oil.

[0158] Stopping procedure: Circulation pump 6 stops, and valves 11, 12, 13 and 15 are in the open state.

[0159] Shutdown procedure: The first valve 11 and the return oil line 4 are closed, while the first oil supply line 17 and the second oil supply line 18 are open.

[0160] The specific embodiments of this application will now be described with reference to the accompanying drawings.

[0161] This application aims to solve the problem that during the startup process of the heat transfer oil system 1, when the pipeline is partially raised to a higher position, the startup pressure is insufficient, and the system cannot start normally.

[0162] In this embodiment of the application, an auxiliary starting device 10 is provided in the heat transfer oil system 1. The device includes a starting tank 16, the height of which is higher than the highest point 5 of the return oil pipeline. The starting tank 16 is connected to the highest point 5 of the return oil pipeline through a first oil supply pipe 17 and a second oil supply pipe 18. An isolation valve (first valve 11) is provided on the return oil pipeline 4 between the first oil supply pipe 17 and the second oil supply pipe 18 of the starting tank 16. The second valve 12 provided on the first oil supply pipe 17 is configured to switch the on / off state of the first oil supply pipe 17, and the third valve 13 provided on the second oil supply pipe 18 is configured to switch the on / off state of the second oil supply pipe 18.

[0163] Furthermore, the auxiliary starting device 10 is also equipped with a safety valve 23, an overflow branch, a nitrogen seal and other components connected to the starting tank 16.

[0164] Furthermore, the first valve 11, the second valve 12, and the third valve 13 can be integrated into a valve group.

[0165] By setting an auxiliary starting device 10 at the highest point of the heat transfer oil pipeline, during the heat transfer oil start-up process, the nitrogen seal is opened, the first valve 11 is closed, and the second valve 12, the third valve 13, the fourth valve 14 and the fifth valve 15 are opened. After the oil is injected to the standard liquid level of the start-up tank 16, the return oil pump group (circulation pump 6) is started, the second valve 12, the third valve 13, the fourth valve 14 and the fifth valve 15 are quickly closed, and the first valve 11 is opened. At this time, the heat transfer oil system 1 is siphoned, and the heat transfer oil can circulate stably in the system, realizing the start-up of the heat transfer oil system 1.

[0166] This solution is applicable to large-scale industrial heat transfer oil circulation systems. It adds components such as a start-up tank 16, nitrogen sealing, and safety valve 23. Based on the siphon principle, it lowers the height of the high-level oil tank 7, reduces the overall operating pressure, reduces operating energy consumption, lowers the start-up pressure of the heat transfer oil system 1, and improves the safety of starting the heat transfer oil system 1.

[0167] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0168] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0169] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0170] The above embodiments are merely illustrative of the technical solutions of this application and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and all should be covered within the scope of protection claimed in this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of protection claimed in this application.

Claims

1. A heat transfer oil system, characterized in that, include Thermal oil boilers are used to heat thermal oil. The return oil pipeline is configured to connect the thermal oil boiler to the heat-consuming equipment. An auxiliary starting device, comprising a starting tank, the height of which is higher than the highest point of the return oil pipeline, and the starting tank being connected to the highest point of the return oil pipeline via an oil supply pipeline; Along the flow direction of the heat transfer oil in the return oil pipeline, the highest point of the return oil pipeline has a first node and a second node, and a first valve for switching the on / off state of the return oil pipeline is provided between the first node and the second node. The inlet of the start-up tank is connected to the first node via a first oil supply pipe, and a second valve located on the first oil supply pipe is configured to switch the on / off state of the first oil supply pipe. The outlet of the start-up tank is connected to the second node via a second oil pipeline, and a third valve located on the second oil pipeline is configured to switch the on / off state of the second oil pipeline.

2. The heat transfer oil system according to claim 1, characterized in that, The auxiliary starting device has a pre-start state; In the pre-start state, the first valve is in the closed state, the return oil line is in the closed state, the second valve and the third valve are in the open state, and the first oil supply line and the second oil supply line are in the open state.

3. The heat transfer oil system according to claim 2, characterized in that, The auxiliary starting device has a post-start state; In the initial state, the first valve is in the open state, the return oil pipeline is in the open state, the second valve and the third valve are in the closed state, and the first oil delivery pipeline and the second oil delivery pipeline are in the closed state.

4. The heat transfer oil system according to claim 3, characterized in that, The auxiliary starting device also has a stop state; in the stop state, the first valve, the second valve and the third valve are in the conducting state, and the return oil pipeline, the first oil supply pipeline and the second oil supply pipeline are in the conducting state.

5. The heat transfer oil system according to claim 2, characterized in that, The auxiliary starting device includes an oil replenishment pipeline connected to the starting tank. The oil replenishment pipeline is equipped with a fourth valve, which is used to switch the oil replenishment pipeline on and off. The starting tank is equipped with a level gauge.

6. The heat transfer oil system according to claim 5, characterized in that, In the pre-start state, the fourth valve is in the open state, and the oil replenishment pipeline is connected to the start-up tank.

7. The heat transfer oil system according to any one of claims 1 to 6, characterized in that, The auxiliary starting device also includes an overflow branch, which includes an overflow tank connected to the starting tank. The overflow tank is used to collect the heat transfer oil overflowing from the starting tank.

8. The heat transfer oil system according to claim 7, characterized in that, In the overflow branch, the flow stabilizer is located between the starter tank and the overflow tank, and the safety valve is located between the flow stabilizer and the starter tank. The safety valve is used to discharge gas from the heat transfer oil system.

9. The heat transfer oil system according to any one of claims 1 to 6, characterized in that, The nitrogen source is connected to the start-up tank via a pipeline.

10. The heat transfer oil system according to any one of claims 1 to 6, characterized in that, The return oil pipeline has multiple highest points at the same height. Along the flow direction of the heat transfer oil in the return oil pipeline, the auxiliary starting device is located at the highest point closest to the heat transfer oil boiler.

11. The heat transfer oil system according to any one of claims 1 to 6, characterized in that, The first valve, the second valve, and the third valve are an integrated valve assembly.

12. The heat transfer oil system according to any one of claims 1 to 6, characterized in that, The return oil pipeline, which connects the heat-using equipment and the auxiliary starting device, is inclined with an upward slope along the flow direction of the heat transfer oil in the return oil pipeline.

13. The heat transfer oil system according to any one of claims 1 to 6, characterized in that, The auxiliary starting device also has a shutdown state; in the shutdown state, the first valve is in the closed state, the second valve and the third valve are in the open state, the return oil line is in the closed state, and the first oil supply line and the second oil supply line are in the open state.

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