Automatic can cutting method for liquid storage tank

Abstract

The present application belongs to the technical field of safe operation of liquid storage tank, and in particular to an automatic tank cutting method for liquid storage tank, comprising a first liquid storage tank and a second liquid storage tank, which are provided with automatic liquid level meters, high-low liquid level switches, electromagnetic valves, central control room automatic control systems, sound-light alarm devices, monitoring operation stations in central control watch rooms and corresponding oil depot integrated management systems. The present application is provided with two functions of soft reporting and hard reporting in the system. In the production operation of the storage tank, any one of the soft reporting and hard reporting is triggered, and the system will automatically complete the tank cutting operation, which fundamentally solves the technical problems of roof collapse prevention and vacuumization prevention, and ensures the safe and stable operation of the oil depot storage tank.

Description

Technical Field

[0001] This invention relates to the field of safe operation technology of liquid storage tanks, specifically to an automatic tank switching method for liquid storage tanks. Background Technology

[0002] Enterprises engaged in the production, operation, and storage of hazardous chemicals must consciously comply with laws, regulations, and standards related to safe production. Tank collapse and cavitation are significant risks in oil depot operations. A tank collapse not only results in oil loss but can also trigger oil fires, explosions, and environmental pollution, causing serious casualties and property damage, and severely impacting the storage company—even leading to devastating consequences. Tank cavitation and the resulting cavitation also pose significant risks to oil depot operations. Tank collapse and cavitation have become crucial aspects of current oil depot safety management and the daily supervision of emergency management departments.

[0003] The existing technology has the following defects or problems: 1. During the oil depot's oil receiving process, when the liquid level reaches the high-high level of the tank, the high-high level alarm simultaneously interlocks and closes the control valve of the tank's inlet pipeline. However, the system does not interlock with the various oil pumps used for oil delivery at this time. Even with the tank inlet closed, the pumps continue to operate and deliver oil, often causing pressure buildup in the receiving pipeline. While mitigating the risk of tank overflow, this increases the numerous risks associated with pipeline pressure buildup (such as pipeline rupture, gasket failure, and pump damage). The consequences and losses from these risks are no less than those from a tank overflow. This is especially true for long-distance pipeline oil delivery to depots; accidents caused by pipeline pressure buildup result in even greater losses. 2. When oil products are received into the storage facility, the interlocking of the oil tank inlet pipeline's electric valve will cause the oil depot to suspend its oil receiving operations, affecting the depot's operational efficiency. This is especially true for oil depots that use pipeline transportation for receiving oil, where the depot and the transportation company are often two separate entities. Resuming pipeline transportation after a suspension requires simultaneous contact and confirmation from multiple departments and companies, increasing workload and significantly impacting efficiency. 3. Oil depot design specifications clearly state that external and internal floating roof tanks with a capacity of 50,000 cubic meters or more should be equipped with low-level alarms and interlocked pump shutdown mechanisms. Therefore, tanks with a capacity less than 50,000 cubic meters face the risk of tank evacuation and frequent floating roof adjustments. Furthermore, if tank evacuation or floating roof adjustments occur, in addition to increasing the associated risks, it also affects the operational efficiency of the oil depot. 4. In most oil product storage and trading companies, the technical measures to prevent overflow at oil tank inlets and to prevent cavitation during oil dispensing rely solely on operator monitoring. The comprehensive quality and sense of responsibility of the operators play a crucial role, and the two major risks of overflow and cavitation in liquid storage tanks are not fundamentally controlled. It should be noted that the above content falls within the inventor's technical knowledge and does not necessarily constitute prior art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an automatic tank-switching method for liquid storage tanks, solving the current problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an automatic tank switching method for liquid storage tanks, comprising a first liquid storage tank and a second liquid storage tank, wherein the first liquid storage tank and the second liquid storage tank are equipped with an automatic liquid level gauge, a high and low liquid level switch, a solenoid valve, a central control room automatic control system, an audible and visual alarm device, a central control duty room monitoring and operation station, and a corresponding oil depot integrated management system; The first liquid storage tank and the second liquid storage tank are different storage tanks for the same type of oil. The inlet lines, outlet lines, and guide pipes of all storage tanks for the same type of oil are interconnected, and the inlet lines, outlet lines, and guide pipes are set independently. The bus of the solenoid valve adopts one of MODBUS ring network and PROFIBUS / DP tree network, and is automatically controlled and monitored by PLC. The automatic level gauge is connected to the central control room's automatic control system via fieldbus to detect the tank's liquid level, water level, temperature, and density. The central control room's automatic control system collects data and calculates density, volume, and mass in real time, displaying the tank's status and inventory in graphical and data formats. For moving tanks, the system issues an audible and visual alarm and automatically switches the tank when the liquid level reaches the set height. For stationary tanks, the system alarms when the liquid level changes beyond the set range. The high and low liquid level detection device adopts an external tuning fork liquid level switch, with an external tuning fork switch for high liquid level and an external tuning fork switch for low liquid level installed respectively. When the liquid level of the storage tank is detected to be higher than the high-high alarm position or lower than the low alarm position, the information is transmitted to the central control room automatic control system to trigger the automatic tank switching interlock process. This detection is called hard alarm. The central control room's automatic control system is responsible for signal acquisition, data analysis, command issuance, and operation monitoring, and it interfaces with the superior information management system. The system supports remote control of electric valves and automated process flow; the system provides advance voice announcements when the electric valves are activated; the operating room automation system database is isolated from other management system databases, and the industrial control network is separated from the office network; The monitoring station is located in the central control room and can execute commands issued by the central control room's automatic control system. The audible and visual alarm device is installed in the central control room and is used to issue audible and visual alerts when the storage tank is abnormal.

[0006] In some embodiments, the power supply cable used is an armored cable, and the information communication signal line has a shielding function; the level gauge, high and low level switch, solenoid valve, central control room automatic control system, audible and visual alarm device, monitoring operation station and integrated management system are equipped with dual power supply and UPS uninterruptible power supply. The system power supply adopts redundant configuration, and the uninterruptible power supply is switched through a dual-circuit power switching device. The system is also equipped with an automatic isolation voltage regulator.

[0007] In some embodiments, the electric valve body is equipped with local, stop, remote, and on / off selection operation keys, enabling on-site and remote operation; the opening and closing data of the electric valve are stored in the database of the central control room's automatic control system; the operation adopts an operating system of one person operating remotely from the central control room, one person verifying on-site, and the duty leader confirming in the central control room; the electric valve body has a switch travel indicator, with the switch position expressed as a percentage, and the valve status is marked with different colors on the monitoring operation station computer; when the electric valve is switched to local operation, the monitoring operation station computer cannot perform remote operation.

[0008] In some embodiments, the automatic level gauge measures the total oil-water level, water level, oil density, and temperature in real time, and the system automatically calculates the volume and weight. The storage tank is also equipped with a multi-point average thermometer, a differential pressure transmitter, and a level alarm switch to achieve centralized monitoring, alarm linkage, data sharing, and inventory management. The level gauge data is crucial for the system to implement soft reporting and tank-switching commands. The high and low level detection device serves as the second line of defense for hard reporting; when the level gauge malfunctions, the system automatically matches a storage tank that meets the requirements for receiving and dispatching operations for automatic tank switching.

[0009] In some embodiments, the central control room automation system uses a high-capacity dedicated server with redundant configuration. The network is isolated by a hardware firewall, and the CPU, power module, and communication module are all 1:1 redundant. It is configured with one set of historical database servers and one set of real-time database servers, each with two servers for mutual redundancy. The system includes a PLC, controller, server, operator station, and industrial Ethernet equipment. The PLC is responsible for connecting field devices and performing data acquisition and monitoring. The automation system is set with high alarm, high-high alarm, low alarm, and low-low alarm data. When the level gauge data reaches the set value, it automatically alarms and cuts off the tank. When the level gauge fails and an external tuning fork switch signal is received, it initiates automatic tank cutting operation.

[0010] In some embodiments, the monitoring station uses an industrial control computer, configured with at least a dual-core CPU with a main frequency of 2.2GHz, 2MB Cache, 2G SDRAM, 516GB HDD, a read / write optical drive, dual 100Mbps network cards, multiple graphics cards, 512MB display memory, a keyboard and mouse, and a 22" LCD screen; the station provides a graphical operation mode, allowing operators to perform operations and monitoring through the monitoring station computer.

[0011] In some embodiments, the audible and visual alarm device is installed directly in front of the monitoring personnel in the central control room. When the system receives abnormal or fault information, it issues an audible and visual alarm to prompt human intervention. In some embodiments, the method specifically involves the following steps: Step 1: The oil depot's hardware and software meet the technical requirements for automatic tank switching, and the system is operating normally. When the tank switching conditions are triggered, the system will automatically switch tanks. Step 2: Start with soft interlock for tank switching, start with hard interlock for tank switching; Step 3: During production operation, if the oil receiving tank level is higher than the high alarm setting height and the oil dispensing tank level is lower than the low alarm setting height, the audible and visual alarm device will issue an audible and visual alarm. Step 4: As the oil receiving tank level continues to rise, it will report the set height when it reaches the high-high level and the oil issuing tank level will report the low-low level. The system will automatically match the standby tank, and the standby tank will be displayed on the tank switching screen and a timer will start for 120 seconds. Step 5: The timing and oil collection system automatically opens the electric valve for oil inlet of the spare tank, and the oil dispensing system automatically opens the electric valve for oil dispensing from the spare tank. Step Six: Open the electric valve for the oil receiving backup tank and the electric valve for the oil dispensing backup tank, and close the electric valves of the original receiving and dispensing tanks. Step 7: After the electric valves of the original receiving and dispatching oil tanks are closed, the automatic tank switching is completed; Step 8: If the liquid level of the receiving and dispatching tanks fails or malfunctions, and the liquid level of the receiving tank reaches the high alarm position of the external tuning fork switch installed on the storage tank or the liquid level of the dispatching tank is lower than the low alarm position of the external tuning fork switch installed on the storage tank, the system will execute the automatic tank switching process to complete the tank switching operation.

[0012] Compared with the prior art, the present invention provides an automatic tank switching method for liquid storage tanks, which has the following beneficial effects: This invention discloses an automatic tank switching method for liquid storage tanks. It avoids various risks arising from pipeline pressure buildup caused by the interlocking of inlet and outlet valves required by existing standards and regulations. Simultaneously, automatic tank switching during liquid storage tank operation fundamentally eliminates the risks of tank overflow and cavitation, while also improving work efficiency. The monitoring station in the central control room can present the real-time status of the liquid storage tank to the control room personnel in a graphical format, making monitoring more intuitive and operation more convenient. The application of automatic tank switching technology, including voice broadcasts of valve opening and closing and audible and visual alarms, alerts control room personnel to abnormal situations during oil depot production operations. This invention fundamentally solves the risk of liquid storage tank overflow and cavitation, and possesses high adaptability, applicable to any liquid storage tank scenario. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the automatic tank cutting mechanism for liquid storage tanks according to the present invention.

[0014] In the diagram: 1. First liquid storage tank; 2. Second liquid storage tank; 3. Oil receiving pipeline; 4. Oil dispensing pipeline; 5. Guide pipeline; 6. Oil receiving pipeline solenoid valve A; 7. Guide pipeline solenoid valve A; 8. Oil dispensing pipeline solenoid valve A; 9. Tank root solenoid valve A; 10. Second liquid storage tank high level switch; 11. Second liquid storage tank low level switch; 12. Second liquid storage tank automatic level gauge; 13. Oil receiving pipeline solenoid valve B; 14. Guide pipeline solenoid valve B; 15. Oil dispensing pipeline solenoid valve B; 16. Tank root solenoid valve B; 17. First liquid storage tank high level switch; 18. First liquid storage tank low level switch; 19. First liquid storage tank automatic level gauge; 20. Central control room automatic control system; 21. Audible and visual alarm device; 22. Central control duty room monitoring and operation station; 23. Oil depot integrated management system. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0017] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0018] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0019] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0020] Please see Figure 1In this embodiment: an automatic tank switching method for liquid storage tanks includes a first liquid storage tank 1 and a second liquid storage tank 2. The first liquid storage tank and the second liquid storage tank are respectively equipped with an automatic liquid level gauge 19 for the first liquid storage tank, an automatic liquid level gauge 12 for the second liquid storage tank, a low liquid level switch 18 for the first liquid storage tank, a low liquid level switch 11 for the second liquid storage tank, an oil receiving pipeline solenoid valve A6; an oil guiding pipeline solenoid valve A7; an oil dispensing pipeline solenoid valve A8; a tank root solenoid valve A9; a tank root solenoid valve B16; a central control room automatic control system 20; an audible and visual alarm device 21; a central control duty room monitoring and operation station 22; and a corresponding oil depot integrated management system 23. The first liquid storage tank 1 and the second liquid storage tank 2 are connected by an oil receiving pipeline 3, an oil dispensing pipeline 4, and a tank guiding pipeline 5. The first liquid storage tank 1 and the second liquid storage tank 2 are different storage tanks for the same type of oil. The oil receiving pipeline 3, oil dispensing pipeline 4 and guide tank pipeline 5 of all oil storage tanks with the same type of oil are interconnected and set up independently. The bus of each group of solenoid valves adopts one of MODBUS ring network and PROFIBUS / DP tree network, and is automatically controlled and monitored by PLC. The automatic level gauges 19 and 12 of the first and second liquid storage tanks are connected to the central control room's automatic control system 20 via fieldbus. They detect the tank's liquid level, water level, temperature, and density. The central control room's automatic control system 20 collects data and calculates density, volume, and mass in real time, displaying the tank's status and inventory in graphical and data formats. For moving tanks, the system issues an audible and visual alarm 21 and automatically switches the tank when the liquid level reaches the set height. For stationary tanks, the system alarms when the liquid level changes beyond the set range. The low level switch 18 for the first liquid storage tank and the low level switch 11 for the second liquid storage tank are externally mounted tuning fork level switches. They are respectively installed with externally mounted tuning fork switches for high level and externally mounted tuning fork switches for low level. When the liquid level of the storage tank is detected to be higher than the high-high alarm position or lower than the low alarm position, the information is transmitted to the automatic control system 20 in the central control room to trigger the automatic tank switching interlock process. This detection is called hard alarm. The central control room's automatic control system 20 is responsible for signal acquisition, data analysis, command issuance, and operation monitoring, and it also interfaces with the superior information management system. The system supports remote control of electric valves and automated process flow; the system provides advance voice announcements when electric valves are activated; the central control room's automation system 20 is isolated from other management system databases, and the industrial control network is separate from the office network; The monitoring and operation station 22 in the central control room is located in the central control room and can execute the instructions issued by the central control room's automatic control system. The audible and visual alarm device 21 is installed in the central control room and is used to issue audible and visual prompts when the storage tank is abnormal.

[0021] In this embodiment, the power supply cable used is an armored cable, and the information communication signal line has a shielding function. The first liquid storage tank and the second liquid storage tank are respectively equipped with an automatic liquid level gauge 19 for the first liquid storage tank, an automatic liquid level gauge 12 for the second liquid storage tank, a low liquid level switch 18 for the first liquid storage tank, a low liquid level switch 11 for the second liquid storage tank, an oil receiving pipeline solenoid valve A6, an oil guiding pipeline solenoid valve A7, an oil discharging pipeline solenoid valve A8, a tank root solenoid valve A9, a tank root solenoid valve B16, a central control room automatic control system 20, an audible and visual alarm device 21, a central control duty room monitoring operation station 22, and the corresponding oil depot integrated management system 23. All of these adopt dual power supply and are equipped with UPS uninterruptible power supply. The system power supply adopts redundant configuration, and the uninterruptible power supplies are switched through a dual-circuit power switching device. The system is also equipped with an automatic isolation voltage regulator.

[0022] In this embodiment, the electric valve body is equipped with local, stop, remote, and on / off selection operation keys, enabling both on-site and remote operation. The opening and closing data of the electric valve are stored in the database of the automatic control system in the central control room. During operation, a system is adopted in which one person operates remotely from the central control room, one person verifies on-site, and the duty leader confirms in the central control room. The electric valve body has a switch travel indicator, and the switch position is expressed as a percentage. The valve status is marked with different colors on the monitoring and operation station computer. When the electric valve is switched to local operation, the monitoring and operation station computer cannot perform remote operation.

[0023] In this embodiment, the automatic level gauge 19 of the first liquid storage tank and the automatic level gauge 12 of the second liquid storage tank measure the total oil-water level, water level, oil density, and temperature in real time, and the system automatically calculates the volume and weight. The storage tanks are also equipped with multi-point average thermometers, differential pressure transmitters, and level alarm switches to achieve centralized monitoring, alarm linkage, data sharing, and inventory management. The level gauge data is the key data for the system to realize soft reporting and tank switching commands. The high and low level detection device is the second barrier to realize hard reporting. When the level gauge fails, the system automatically matches the storage tank that meets the receiving and sending operations and automatically switches the tank.

[0024] In this embodiment, the central control room automatic control system 20 adopts a high-capacity dedicated server with redundant configuration. The network is isolated by a hardware firewall, and the CPU, power module, and communication module are all redundant in a 1:1 ratio. It is configured with one set of historical database server and one set of real-time database server, each with two servers for mutual redundancy. The system includes PLC, controller, server, operator station, and industrial Ethernet equipment. The PLC is responsible for connecting field devices and performing data acquisition and monitoring. The automatic control system is set with high alarm, high-high alarm, low alarm, and low-low alarm data. When the liquid level gauge data reaches the set value, it automatically alarms and cuts off the tank. When the liquid level gauge fails and receives information from the external tuning fork switch, it starts the automatic tank cutting operation.

[0025] In this embodiment, the central control room monitoring station 22 adopts an industrial control computer, configured with at least a dual-core CPU with a main frequency of 2.2GHz, 2MB Cache, 2G SDRAM, 516GB HD, a read / write optical drive, dual 100Mbps network cards, multiple graphics cards, 512MB display memory, a keyboard and mouse, and a 22" LCD. The station provides a graphical operation mode, and operators can operate and monitor through the monitoring station computer.

[0026] In this embodiment, the audible and visual alarm device 21 is installed directly in front of the monitoring personnel in the central control room. When the system receives abnormal or fault information, it will issue an audible and visual alarm to prompt human intervention. The specific steps in this embodiment are as follows: Step 1: The oil depot's hardware and software meet the technical requirements for automatic tank switching, and the system is operating normally. When the tank switching conditions are triggered, the system will automatically switch tanks. Step 2: Start with soft interlock for tank switching, start with hard interlock for tank switching; Step 3: During production operation, if the oil receiving tank level is higher than the high alarm setting height and the oil dispensing tank level is lower than the low alarm setting height, the audible and visual alarm device will issue an audible and visual alarm. Step 4: As the oil receiving tank level continues to rise, it will report the set height when it reaches the high-high level and the oil issuing tank level will report the low-low level. The system will automatically match the standby tank, and the standby tank will be displayed on the tank switching screen and a timer will start for 120 seconds. Step 5: The timing and oil collection system automatically opens the electric valve for oil inlet of the spare tank, and the oil dispensing system automatically opens the electric valve for oil dispensing from the spare tank. Step Six: Open the electric valve for the oil receiving backup tank and the electric valve for the oil dispensing backup tank, and close the electric valves of the original receiving and dispensing tanks. Step 7: After the electric valves of the original receiving and dispatching oil tanks are closed, the automatic tank switching is completed; Step 8: If the liquid level of the receiving and dispatching tanks fails or malfunctions, and the liquid level of the receiving tank reaches the high alarm position of the external tuning fork switch installed on the storage tank or the liquid level of the dispatching tank is lower than the low alarm position of the external tuning fork switch installed on the storage tank, the system will execute the automatic tank switching process to complete the tank switching operation.

[0027] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0028] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automatic tank-switching method for liquid storage tanks, characterized in that, It includes a first liquid storage tank and a second liquid storage tank. The first liquid storage tank and the second liquid storage tank are equipped with an automatic liquid level gauge, a high and low liquid level switch, a solenoid valve, a central control room automatic control system, an audible and visual alarm device, a central control duty room monitoring and operation station, and a corresponding oil depot integrated management system. The first liquid storage tank and the second liquid storage tank are connected by an oil receiving pipeline, an oil dispensing pipeline, and a tank guide pipeline. The first liquid storage tank and the second liquid storage tank are different storage tanks for the same type of oil. The inlet lines, outlet lines, and guide pipes of all storage tanks for the same type of oil are interconnected, and the inlet lines, outlet lines, and guide pipes are set independently. The bus of the solenoid valve adopts one of MODBUS ring network and PROFIBUS / DP tree network, and is automatically controlled and monitored by PLC. The automatic level gauge is connected to the central control room's automatic control system via fieldbus to detect the tank's liquid level, water level, temperature, and density. The central control room's automatic control system collects data and calculates density, volume, and mass in real time, displaying the tank's status and inventory in graphical and data formats. For moving tanks, the system issues an audible and visual alarm and automatically switches the tank when the liquid level reaches the set height. For stationary tanks, the system alarms when the liquid level changes beyond the set range. The high and low liquid level detection device uses an external tuning fork switch (or other liquid level detection instrument), with an external tuning fork switch for high liquid level and an external tuning fork switch for low liquid level installed respectively. When the liquid level in the storage tank is detected to be higher than the high-high alarm position or lower than the low alarm position, the information is transmitted to the central control room automatic control system to trigger the automatic tank switching interlock process. This detection is called hard alarm. The central control room's automatic control system is responsible for signal acquisition, data analysis, command issuance, and operation monitoring, and it interfaces with the superior information management system. The system supports remote control of electric valves and automated process flow; the system provides advance voice announcements when the electric valves are activated. The operating room automation system database is isolated from other management system databases, and the industrial control network is separated from the office network. The monitoring station is located in the central control room and can execute commands issued by the central control room's automatic control system. The audible and visual alarm device is installed in the central control room and is used to issue audible and visual alerts when the storage tank is abnormal.

2. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The power supply cables used are armored cables, and the information communication signal lines are shielded. The level gauges, high and low level switches, solenoid valves, central control room automatic control system, audible and visual alarm devices, monitoring operation station and integrated management system are powered by dual power supplies and equipped with UPS uninterruptible power supplies. The system power supply adopts redundant configuration, and the uninterruptible power supplies are switched through a dual-circuit power switching device. The system is also equipped with an automatic isolation voltage regulator.

3. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The electric valve body is equipped with local, stop, remote, and on / off selection operation keys, enabling both on-site and remote operation. The opening and closing data of the electric valve are stored in the database of the central control room's automatic control system. During operation, a system is adopted in which one person operates remotely from the central control room, one person verifies on-site, and the duty leader confirms in the central control room. The electric valve body has a switch travel indicator, with the switch position expressed as a percentage. The valve status is marked with different colors on the monitoring and operation station computer. When the electric valve is switched to local operation from the field, the monitoring and operation station computer cannot perform remote operation.

4. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The automatic level gauge measures the total oil-water level, water level, oil density, and temperature in real time, and the system automatically calculates the volume and weight. The storage tank is also equipped with a multi-point average thermometer, a differential pressure transmitter, and a level alarm switch to achieve centralized monitoring, alarm linkage, data sharing, and inventory management. The level gauge data is the key data for the system to realize soft reporting and tank switching commands. The high and low level detection device is the second barrier to realize hard reporting. When the level gauge fails, the system automatically matches the storage tank that meets the receiving and sending operations and automatically switches the tank.

5. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The central control room automation system uses a high-capacity dedicated server with redundant configuration. The network is isolated by a hardware firewall. The CPU, power module, and communication module are all redundant in a 1:1 ratio. It is equipped with one set of historical database server and one set of real-time database server, each with two servers for mutual redundancy. The system includes PLC, controller, server, operator station, and industrial Ethernet network equipment. The PLC is responsible for connecting field equipment and collecting and monitoring data. The automatic control system is set with high alarm, high-high alarm, low alarm, and low-low alarm data. When the liquid level gauge data reaches the set value, it will automatically alarm and switch tanks. When the liquid level gauge fails and receives information from the external tuning fork switch, it will start the automatic tank switching operation.

6. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The monitoring and operation station uses an industrial control computer, configured with at least a dual-core CPU with a main frequency of 2.2GHz, 2MB cache, 2G SDRAM, 516GB HDD, a read / write optical drive, dual 100Mbps network cards, multiple graphics cards, 512MB display memory, a keyboard and mouse, and a 22" LCD screen. The operation station provides a graphical operation mode, allowing operators to perform operations and monitoring through the monitoring and operation station computer.

7. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The audible and visual alarm device is installed directly in front of the monitoring personnel in the central control room. When the system receives abnormal or fault information, it will issue an audible and visual alarm to prompt human intervention.

8. The automatic tank switching method for a liquid storage tank according to claim 1, characterized in that: The specific steps of this method are as follows: Step 1: The oil depot's hardware and software meet the technical requirements for automatic tank switching, and the system is operating normally. When the tank switching conditions are triggered, the system will automatically switch tanks. Step 2: Start with soft interlock for tank switching, start with hard interlock for tank switching; Step 3: During production operation, if the oil receiving tank level is higher than the high alarm setting height and the oil dispensing tank level is lower than the low alarm setting height, the audible and visual alarm device will issue an audible and visual alarm. Step 4: As the oil receiving tank level continues to rise, it will report the set height when it reaches the high-high level and the oil issuing tank level will report the low-low level. The system will automatically match the standby tank, and the standby tank will be displayed on the tank switching screen and a timer will start for 120 seconds. Step 5: The timing and oil collection system automatically opens the electric valve for oil inlet of the spare tank, and the oil dispensing system automatically opens the electric valve for oil dispensing from the spare tank. Step Six: Open the electric valve for the oil receiving backup tank and the electric valve for the oil dispensing backup tank, and close the electric valves of the original receiving and dispensing tanks. Step 7: After the electric valves of the original receiving and dispatching oil tanks are closed, the automatic tank switching is completed; Step 8: If the liquid level of the receiving and dispatching tanks fails or malfunctions, and the liquid level of the receiving tank reaches the high alarm position of the external tuning fork switch installed on the storage tank or the liquid level of the dispatching tank is lower than the low alarm position of the external tuning fork switch installed on the storage tank, the system will execute the automatic tank switching process to complete the tank switching operation.

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