Normal pressure storage tank closed water cutting device capable of secondary dewatering

Abstract

The utility model relates to a kind of atmospheric storage tank closed water cutting device capable of secondary dewatering, including at least one atmospheric storage tank, pipeline automatic closed water cutting device and secondary dewatering tank, the bottom sidewall of each atmospheric storage tank is connected and communicated with the top sidewall of secondary dewatering tank by conveying pipeline, and pipeline automatic closed water cutting device is equipped on conveying pipeline;Water phase area and oil phase area are formed by partition in secondary dewatering tank, water phase area is connected and communicated with tank area sewage pipe network and tank area waste gas treatment device respectively by drainage pipeline and exhaust pipeline, and oil phase area is connected with the top sidewall or downstream production device of atmospheric storage tank by oil discharge pipeline;Nitrogen gas conveying pipe and pressure transmitter are connected on the top of secondary dewatering tank.The utility model is equipped with pipeline automatic closed water cutting device and secondary dewatering tank, can realize that water cutting process is carried out in closed system, greatly reduces the unorganized emission of volatile organic compounds, avoids the product loss caused by "cutting belt oil".

Description

Technical Field

[0001] This utility model relates to the technical field of oil-water separation, specifically to a closed-type water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration. Background Technology

[0002] Traditional atmospheric pressure storage tanks require manual water cutting, which involves observing the appearance and state of the water flow to determine whether it is water or oil. Operators are exposed to the water inlet for extended periods, directly inhaling high concentrations of toxic and harmful gases (especially benzene and hydrogen sulfide), causing chronic or acute damage to the respiratory and nervous systems, and even posing a risk of poisoning and suffocation.

[0003] The oil-water separation process relies heavily on the operator's experience and sense of responsibility. Manual operation cannot strictly control oil-water separation. If the operator is distracted, fatigued, or inexperienced, and fails to close the valve in time, it can lead to an "oil spill" accident. This means that a large amount of oil is accidentally discharged, which not only causes huge economic losses but also poses a significant safety hazard.

[0004] Oily wastewater, if not properly collected and treated (such as being directly discharged into rainwater systems or onto the ground), can cause serious pollution of soil and groundwater.

[0005] During the water-cutting process, large amounts of toxic and harmful VOCs and malodorous gases, such as benzene, toluene, xylene, and hydrogen sulfide, are directly released into the atmosphere. This not only causes serious air pollution but also violates increasingly stringent environmental regulations (such as the "Standard for the Control of Unorganized Emissions of Volatile Organic Compounds" GB 37822).

[0006] The invention patent application CN105775460A discloses a method and system for automatically achieving clean water shut-off in storage tanks using a multi-opening control valve. The method involves the controller operating a shut-off valve to open wide when the oil-water detection sensor on the automatic shut-off device first detects water as the medium in the container at its installation location. When the oil-water detection sensor detects oil as the medium, the controller stops the shut-off. When the oil-water detection sensor detects water again, the controller stops the shut-off. The automatic water-cutting valve operates at a small opening. When the oil-water detection sensor on the automatic water-cutting device detects oil in the container at its installation location again, the controller stops the water-cutting valve. Alternatively, the automatic water-cutting device for the storage tank has two parallel oil-water detection sensors, one above the other. When the upper oil-water detection sensor detects water in the container at its installation location, the controller controls the water-cutting valve to first operate at a large opening, then at a small opening, or then at a series of progressively smaller openings. When the lower oil-water detection sensor detects oil in the container at its installation location, the controller stops the water-cutting valve. The container can be a storage tank or a water-cutting tank. This method has the advantage of not significantly affecting the water-cutting efficiency while significantly reducing oil entrainment in the final stage of water cutting.

[0007] The utility model patent with authorization announcement number CN209720551U discloses an automatic water-cutting device for oil tanks, including a shell, a partition that divides the inner cavity of the shell into a first dehydration chamber and a second dehydration chamber, the first dehydration chamber and the second dehydration chamber are connected by a connecting pipe at the bottom of the partition, and one end of the connecting pipe is inserted into the second dehydration chamber with its opening facing upward; a water outlet regulating valve is provided at the lower part of the shell, the water outlet regulating valve is controlled by a first oil-water detector and a second oil-water detector, the first oil-water detector and the second oil-water detector are respectively located at the top of the first dehydration chamber and the second dehydration chamber, and a venting valve is also provided at the top of the second dehydration chamber; the top of the first dehydration chamber is connected to the liquid outlet of the oil tank through a water-cutting pipe. The internal structure of the water-cutting device is divided into a first dehydration chamber and a second dehydration chamber by a partition. The first and second dehydration chambers are detected by a first oil-water detector and a second oil-water detector, respectively. Initially, the clear water deposited at the bottom of the oil tank enters the first dehydration chamber from the outlet through the water-cutting pipe at the top of the shell, and then enters the second dehydration chamber through the connecting pipe at the bottom of the partition. At this time, neither the first nor the second oil-water detector detects the presence of oil, and the water outlet regulating valve is open, allowing water to be discharged (the flow rate of the water outlet regulating valve is small, so both the first and second dehydration chambers can be filled). After the clear water has drained from the bottom of the oil tank, the mixture of oil and water in the tank begins to enter the first dehydration chamber. Because oil is lighter than water, it slowly accumulates at the top of the first dehydration chamber, while water enters the second dehydration chamber through the connecting pipe at the bottom of the partition. When the first oil-water detector detects oil, it immediately closes the water outlet regulating valve to prevent the oil from being cut out. As the clear water slowly settles from the bottom of the oil tank, it further enters the first dehydration chamber. The oil in the first dehydration chamber will return to the oil tank through the water-cutting pipe. If the first oil-water detector in the first dehydration chamber malfunctions and fails to detect the presence of oil, the oil will flow into the second dehydration chamber. When the second oil-water detector detects the oil, it will immediately close the water outlet regulating valve, achieving two-stage detection for water cutting and dehydration, which can effectively prevent oil leakage.

[0008] The invention patent with publication number CN117735106A discloses a closed water-cutting and conveying system for storage tanks without oil and gas volatilization. The system includes a storage tank, a storage tank outlet valve connected sequentially to the bottom of the storage tank, and several water cutters. Each water cutter is connected to a sewage main pipe through a corresponding water cutter connecting pipe. The sewage main pipe has a sewage outlet pipe at its outlet end, and several buffer piston cylinders connected in series are connected to the sewage outlet pipe. Each buffer piston cylinder has a piston inside, and each buffer piston cylinder has a piston height sensor at its top that can detect the height inside the buffer piston cylinder. The piston height sensor is connected to a sewage pump through a controller and a frequency converter to discharge sewage. The controller controls the frequency converter to adjust the speed of the sewage pump, thereby controlling the piston within a set stable height range.

[0009] The invention patent with authorization announcement number CN115924833B discloses a method and system for automatic water cutting in atmospheric pressure storage tanks and closed-loop sewage transportation of multiple storage tanks. Multiple parallel storage tanks are connected downstream via an automatic and efficient water cutting device and then connected to a closed sewage collection and oil-water separation unit for closed-loop sewage transportation. The closed sewage collection and oil-water separation unit consists of a closed, horizontally elongated sewage tank with an inner low-level feed pipe, an inner high-level return oil pipe, and a submerged sludge chamber spaced along its long axis on the bottom wall. A high-level medium detection sensor, higher than the inlet of the inner high-level return oil pipe, is installed on the side wall of the horizontal sewage tank in the area between the inner high-level return oil pipe and the submerged sludge chamber. Low-level medium detection sensors are installed at the height of the bottom and the outlet of the inner low-level feed pipe, respectively, and oil sludge medium detection sensors are installed on the side wall of the submerged oil sludge chamber; the top of the horizontal sewage tank is connected to a pressure gauge and a pressure transmitter sensor electrically connected to the intelligent controller; the top of the horizontal sewage tank is connected upward to a liquid level switch and a pressure nitrogen source through a nitrogen-sealed pressure control valve pipeline and an oil and gas recovery pressure control valve pipeline equipped with a flame arrester; the inner low-level feed pipe of the horizontal sewage tank is connected downward to the downstream end of the sewage conveying unit; the inner high-level oil return pipe is connected downward to the sludge return pump valve pipeline of the storage tank; the submerged oil sludge chamber is connected downward to the oil sludge discharge valve pipeline and a variable flow sewage discharge pump valve pipeline leading to the sewage storage facility; Under the control of the intelligent controller, the inner low-level feed pipe feeds wastewater through the connected wastewater conveying unit within the limits of the set gas phase pressure and liquid level switch. When the liquid level is high and the gas phase pressure is low, pressurized nitrogen is introduced through the nitrogen sealing pressure control valve pipeline. When the gas phase pressure is high and the liquid level is low, oil and gas are output through the oil and gas recovery pressure control valve pipeline. The inner high-level return oil pipe returns oil to the storage tank through the sludge return pump valve pipeline when both the high and low level medium detection sensors detect oil. The submerged sludge chamber discharges water at a large flow rate through the variable flow sewage pump valve pipeline when both the high and low level medium detection sensors detect water, and at a small flow rate within the water level range of the low-level medium detection sensor. When the sludge medium detection sensor detects sludge, the intelligent controller sends a sludge removal signal. Automatic high-efficiency water cutting involves multiple parallel storage tanks undergoing a single automatic high-efficiency water cutting operation. The first automatic high-efficiency water cutting involves the top of an oil-water detection container with three horizontally spaced parallel media detection sensors located in the middle, through a return oil pump valve pipeline, returning oil to the middle layer of the storage tank. A water inlet valve pipeline, connected to the front top and bottom of the oil-water detection container, extends downwards from the bottom side of the storage tank to introduce bottom water. The rear top and rear bottom of the oil-water detection container are connected to a water cutting valve pipeline. The automatic high-efficiency water cutting operates in a continuous water cutting mode. Under the control of the intelligent controller, with the water inlet valve pipeline normally open, the water cutting valve opens when any two media detection sensors detect water; and closes when any one media detection sensor detects oil. Oil return occurs when the water cutting valve pipeline is closed, and the oil-water mixture remaining in the oil-water detection container and water inlet valve pipeline is gradually returned to the storage tank through the return oil pump valve pipeline under the forced return oil pump action. Utility Model Content

[0010] In order to solve one or more technical problems existing in the prior art, this utility model provides a closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration.

[0011] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: This utility model provides a closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration, including at least one atmospheric pressure storage tank, a pipeline-type automatic closed-loop water cutter, and a secondary dehydration tank. The bottom sidewall of each atmospheric pressure storage tank is connected and communicated with the top sidewall of the secondary dehydration tank through a conveying pipeline. The pipeline-type automatic closed-loop water cutter is provided on the conveying pipeline. The secondary dehydration tank is divided into an aqueous phase region and an oil phase region by a partition. The aqueous phase region is connected and communicated with the tank area sewage network and the tank area exhaust gas treatment device through a drainage pipeline and an exhaust pipeline, respectively. The oil phase region is connected and communicated with the top sidewall of the atmospheric pressure storage tank or a downstream production device through an oil discharge pipeline. A nitrogen conveying pipeline and a pressure transmitter are connected to the top of the secondary dehydration tank.

[0012] The beneficial effects of this utility model are as follows: This utility model's closed-loop water-cutting device for atmospheric pressure storage tanks, capable of secondary dehydration, enables the water-cutting process to be carried out in a closed system by setting up a pipeline-type automatic closed-loop water-cutting device and a secondary dehydration tank. Compared with manual valve opening for discharge, this greatly reduces the fugitive emission of volatile organic compounds and avoids product loss caused by "oil-carrying" during water-cutting. Over time, the value of the recovered oil is considerable, and the equipment investment payback period is short. The pipeline-type automatic closed-loop water-cutting device and the secondary dehydration tank work together to continuously and accurately control the water level in the tank, avoiding water level fluctuations that may be caused by manual water-cutting. This is conducive to the stable operation of subsequent processes and is an inevitable trend and mandatory requirement for industry development.

[0013] Based on the above technical solution, the present invention can be further improved as follows.

[0014] Furthermore, the aqueous phase area of ​​the secondary dehydration tank is connected to a first level gauge, and a water pump is installed on the drain pipe. The first level gauge is connected to the water pump and interlocks to start and stop the water pump.

[0015] The beneficial effect of adopting the above-mentioned further solution is that by setting a first level gauge and using the first level gauge to interlock the start and stop of the water pump, the liquid level in the secondary dehydration tank can be automatically controlled.

[0016] Furthermore, the oil phase area of ​​the secondary dehydration tank is connected to a second level gauge, and an oil pump is installed on the oil discharge pipeline. The second level gauge is connected to the oil pump and interlocks to start and stop the oil pump.

[0017] The beneficial effect of adopting the above-mentioned further solution is that by setting a second level gauge and using the second level gauge to interlock the start and stop of the water pump, the liquid level in the secondary dehydration tank can be automatically controlled.

[0018] Furthermore, the partition is vertically fixed to the inner wall of the secondary dehydration tank, and an overflow gap is reserved between the partition and the top of the secondary dehydration tank.

[0019] The beneficial effect of adopting the above-mentioned further solution is that secondary oil-water separation can be achieved by setting up a baffle.

[0020] Furthermore, one end of the conveying pipeline extends into the secondary dehydration tank from the top side wall and is arranged near the bottom; one end of the oil discharge pipeline extends into the secondary dehydration tank from the top and is arranged near the bottom.

[0021] The beneficial effect of adopting the above-mentioned further solution is that it enables stable liquid input and output.

[0022] Furthermore, a first pneumatic valve is provided on the nitrogen delivery pipe, and the pressure transmitter is connected to the first pneumatic valve.

[0023] The beneficial effect of adopting the above-mentioned further solution is that by setting the first pneumatic valve, the pressure inside the secondary dehydration tank can be automatically controlled.

[0024] Furthermore, the exhaust pipe is equipped with a second electric valve, a fan, a first flame arrester, and a second flame arrester. The exhaust pipe upstream of the fan is equipped with the second pneumatic valve and the first flame arrester, and the exhaust pipe downstream of the fan is equipped with the second flame arrester.

[0025] The beneficial effect of adopting the above-mentioned further solutions is that by installing flame arresters, the entire system can be prevented from being affected by accidents such as fires and flash explosions.

[0026] Furthermore, the delivery pipeline is equipped with a first manual valve and a third pneumatic valve. The first manual valve is located on the delivery pipeline upstream of the pipeline-type automatic shut-off water cutter, and the third pneumatic valve is located on the delivery pipeline downstream of the pipeline-type automatic shut-off water cutter.

[0027] Furthermore, the secondary dehydration tank is a horizontal tank located underground, while the atmospheric pressure storage tank and the pipeline-type automatic sealed water cutter are both located above ground. Part of the conveying pipeline is located above ground, and another part is located underground; the slope of the conveying pipeline is greater than or equal to 3‰.

[0028] The beneficial effects of adopting the above-mentioned further solution are: the secondary dehydration tank adopts a horizontal structure and is located underground, which enables the liquid to be transported to the secondary dehydration tank by gravity; by setting the slope of the conveying pipeline, it is convenient for the liquid to flow into the secondary dehydration tank by gravity.

[0029] Furthermore, the secondary dehydration tank, conveying pipeline, drainage pipeline, oil discharge pipeline, and exhaust pipeline are all equipped with heat tracing cables.

[0030] The beneficial effect of adopting the above-mentioned further solution is that by setting up a heat tracing cable, the required heat can be provided for the entire system.

[0031] This invention solves the safety hazard problem; the tank water-cutting process is carried out in a closed pipeline and equipment, and the cut-out oily wastewater directly enters the closed recovery system, fundamentally eliminating the unorganized emission of oil and gas into the atmosphere and eliminating the most dangerous fire, explosion, and personnel poisoning links. Operators do not need to manually operate on-site, meeting the safety management regulations for tank farms.

[0032] This invention addresses environmental protection and compliance issues; it significantly reduces VOC emissions, helping businesses meet increasingly stringent environmental regulations. The oil-water mixture is collected in a secondary dehydration tank and then sent to a wastewater treatment plant for centralized, compliant treatment, thus preventing environmental pollution.

[0033] This invention solves the problems of production efficiency and economic benefits. The system automatically determines the oil-water interface through sensors such as resonance, ultrasound, or dielectric constant, achieving precise, automatic, and continuous water separation, thus freeing up labor. It can effectively separate floating oil in the water and recover it to the storage tank, directly reducing product loss.

[0034] The automatic shut-off water-cutting system for atmospheric pressure storage tanks solves more than just the "drainage" operation; it systematically addresses the safety, environmental, and efficiency issues inherent in traditional manual methods through technological upgrades. It is a key component in the petrochemical industry's efforts to promote intelligent manufacturing, build green factories, and create inherently safe enterprises. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the closed-type water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to this utility model; Figure 2 for Figure 1 Schematic diagram of the middle part Figure 1 ; Figure 3 for Figure 1 Schematic diagram of the middle part Figure 2 .

[0036] The attached diagram lists the components represented by each number as follows: 1. Atmospheric pressure storage tank; 2. Pipeline-type automatic sealed water cutter; 3. Secondary dehydration tank; 4. Delivery pipeline; 5. Drainage pipeline; 6. Exhaust pipeline; 7. Oil discharge pipeline; 8. Nitrogen delivery pipeline; 9. Pressure transmitter; 10. First level gauge; 11. Second level gauge; 12. Water pump; 13. Oil pump; 15. Baffle; 16. First pneumatic valve; 17. Second pneumatic valve; 18. Blower; 19. First flame arrester; 20. Second flame arrester; 21. First manual valve; 22. Third pneumatic valve; 23. Heating tape; 24. Second manual valve; 25. Tank farm sewage network; 26. Tank farm exhaust gas treatment device; 27. Nitrogen main pipeline. Detailed Implementation

[0037] The principles and features of this utility model are described below. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0038] Example 1 like Figures 1-3 As shown in this embodiment, a closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration includes at least one atmospheric pressure storage tank 1, a pipeline-type automatic closed-loop water-cutting device 2, and a secondary dehydration tank 3. The bottom sidewall of each atmospheric pressure storage tank 1 is connected and communicates with the top sidewall of the secondary dehydration tank 3 via a conveying pipeline 4. The pipeline-type automatic closed-loop water-cutting device 2 is installed on the conveying pipeline 4. The secondary dehydration tank 3 is divided into an aqueous phase region and an oil phase region by a partition. The aqueous phase region is connected and communicates with the tank area sewage network 25 and the tank area exhaust gas treatment device 26 via a drainage pipeline 5 and an exhaust pipeline 6, respectively. The oil phase region is connected and communicates with the top sidewall of the atmospheric pressure storage tank 1 or a downstream production device via an oil discharge pipeline 7. A nitrogen conveying pipe 8 and a pressure transmitter 9 are connected to the top of the secondary dehydration tank 3. The nitrogen conveying pipe 8 can be connected to the nitrogen main pipe 27.

[0039] like Figure 1 and Figure 3As shown, in this embodiment, one end of the conveying pipeline 4 extends into the secondary dehydration tank 3 from the top side wall and is arranged near the bottom; one end of the oil discharge pipeline 7 extends into the secondary dehydration tank 3 from the top and is arranged near the bottom, enabling stable liquid input and discharge. In this embodiment, the drain pipeline 5 is inserted into the interior of the secondary dehydration tank 3 and communicates with the aqueous phase region, and the drain pipeline 5 is arranged near the bottom of the secondary dehydration tank 3.

[0040] like Figures 1-3 As shown, in one specific embodiment, the secondary dehydration tank 3, the conveying pipeline 4, the drainage pipeline 5, the oil discharge pipeline 7, and the exhaust pipeline 6 are all equipped with heating tapes 23. By setting the heating tapes, the required heat can be provided to the entire system.

[0041] The pipeline-type automatic shut-off water cutter 2 in this embodiment uses a conventional automatic water cutter, which is commercially available. The automatic water cutter uses at least two oil content sensors to simultaneously detect the oil content and control the valve opening. The sensors can be in direct contact with the medium. The oil content in the water affects the viscosity and density of the medium, thus detecting the oil content. The lower the oil content, the stronger the signal. Oil content sensors can be resonant densitometers, electromagnetic wave sensors, capacitive sensors, or ultrasonic sensors. The maximum continuous water cutting speed of the automatic water cutter is >20m / s. 3 The automatic water cutter operates at a rate of / h, with an oil content of no more than 150mg / L, and can completely replace manual water cutting. It reliably returns oil and continuously cuts water; the water cutting process is completely closed.

[0042] Manual water removal from atmospheric pressure storage tanks is a traditional but extremely risky operation. Its core drawback lies in placing operators in a hazardous environment and relying on immediate human judgment. This increases the risk of flammable gas leaks; the volatile flammable gases, mixed with air, can ignite upon contact with an ignition source (such as static electricity or non-explosion-proof tools), potentially causing a fire or even an explosion. Manual water removal is also prone to misjudgment, leading to the discharge of large amounts of oil with the water, causing severe soil and water pollution. Automatic water removal devices, using advanced sensing technologies (such as capacitance, ultrasound, and resonance), accurately detect the oil-water interface, ensuring only water is discharged, not oil. The removed water has an extremely low oil content and can be directly fed into the subsequent wastewater treatment system. This embodiment uses a closed automatic water removal device for the atmospheric pressure storage tank. Utilizing the density difference between oil and water, the automatic water removal device automatically and continuously discharges water while retaining oil within the tank. Operators do not need to be on-site, fundamentally preventing personal injury and human error. The closed-loop water removal process significantly reduces fugitive VOC emissions. It enables continuous 24-hour water cutting, resulting in more thorough drainage and improved oil quality. Remote monitoring and alarm functions are also available.

[0043] This embodiment features a closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration. By incorporating a pipeline-type automatic closed-loop water-cutting device and a secondary dehydration tank, the water-cutting process can be carried out within a closed system. Compared to manual valve opening for discharge, this significantly reduces the fugitive emission of volatile organic compounds and avoids product loss caused by "oil-carrying" during water-cutting. Over time, the recovered oil value is substantial, and the equipment investment payback period is short. The pipeline-type automatic closed-loop water-cutting device and the secondary dehydration tank work together to continuously and accurately control the water level inside the tank, avoiding water level fluctuations that may be caused by manual water-cutting. This is beneficial for the stable operation of subsequent processes and represents an inevitable trend and mandatory requirement for industry development.

[0044] Example 2 Based on Example 1, this example provides a liquid level detection method for a secondary dehydration tank 3. For example... Figure 1 and Figure 3 As shown, in this embodiment, the aqueous phase area of ​​the secondary dehydration tank 3 is connected to a first level gauge 10, and a water pump 12 is installed on the drainage pipe 5. The first level gauge 10 is connected to the water pump 12 and interlocks to start and stop the water pump 12. By setting the first level gauge and using the first level gauge to interlock to start and stop the water pump, automatic control of the liquid level in the secondary dehydration tank can be achieved.

[0045] like Figure 1 and Figure 3 As shown, in this embodiment, the oil phase area of ​​the secondary dehydration tank 3 is connected to a second level gauge 11, and an oil pump 13 is installed on the oil discharge pipeline 7. The second level gauge 11 is connected to the oil pump 13 and interlocks to start and stop the oil pump 13. By setting up the second level gauge and using the second level gauge to interlock the start and stop of the water pump, automatic control of the liquid level in the secondary dehydration tank can be achieved.

[0046] Example 3 Based on Embodiment 1 or Embodiment 2, this embodiment provides a preferred structure for the partition. For example... Figure 1 and Figure 3 As shown, in this embodiment, the partition 15 is vertically fixed on the inner wall of the secondary dehydration tank 3, and a second overflow gap is reserved between the partition 15 and the top of the secondary dehydration tank 3.

[0047] Example 4 Based on any of the above embodiments, this embodiment provides a preferred structure for the nitrogen delivery pipe 8. For example... Figure 1 and Figure 3 As shown, in this embodiment, the nitrogen delivery pipe 8 is equipped with a first pneumatic valve 16. The pressure transmitter 9 is connected to and interlocked with the first pneumatic valve 16 to control the opening degree of the first pneumatic valve 16. By setting the first pneumatic valve, automatic control of the pressure inside the secondary dehydration tank can be achieved. The specific control process is the conventional control process of existing pneumatic valves.

[0048] Example 5 Based on any of the above embodiments, this embodiment provides a preferred structure for the exhaust pipe 6. For example... Figure 1 and Figure 3 As shown, in this embodiment, the exhaust pipe 6 is equipped with a second pneumatic valve 17, a fan 18, a first flame arrester 19, and a second flame arrester 20. The exhaust pipe 6 upstream of the fan 18 is equipped with the second pneumatic valve 17 and the first flame arrester 19, while the exhaust pipe 6 downstream of the fan 18 is equipped with the second flame arrester 20. By installing flame arresters, the entire system can be prevented from being affected in the event of fire, flash explosion, or other accidents.

[0049] The second pneumatic valve 17 can also be interlocked with the pressure transmitter 9 and work in conjunction with the first pneumatic valve 16 to control the pressure inside the secondary dehydration tank. The specific interlocking control process is the existing conventional control technology of pneumatic valves.

[0050] Example 6 Based on any of the above embodiments, this embodiment provides a preferred structure for the conveying pipeline 4. For example... Figure 1 and Figure 3 As shown, in this embodiment, the delivery pipeline 4 is equipped with a first manual valve 21 and a third pneumatic valve 22. The first manual valve 21 is located on the delivery pipeline 4 upstream of the automatic closed-loop water cutter 2, and the third pneumatic valve 22 is located on the delivery pipeline 4 downstream of the automatic closed-loop water cutter 2. The third pneumatic valve 22 can also be interlocked with the first level gauge 10 to control the opening degree of the third pneumatic valve 22, thereby regulating the liquid flow rate. This control process can be implemented using existing conventional technology.

[0051] like Figure 2 As shown, in this embodiment, a second hand valve 24 can also be installed near the interface between the oil drain line 7 and the atmospheric pressure storage tank 1 to control the opening and closing of the pipeline.

[0052] Example 7 Based on any of the above embodiments, this embodiment provides a preferred structure for the conveying pipeline 4. For example... Figure 1 and Figure 3 As shown, in this embodiment, the secondary dehydration tank 3 is a horizontal tank located underground, while the atmospheric pressure storage tank 1 and the pipeline-type automatic sealed water cutter 2 are both located above ground. Part of the conveying pipeline 4 is located above ground, and the other part is located underground; the slope of the conveying pipeline 4 is greater than or equal to 3‰. The secondary dehydration tank adopts a horizontal structure and is located underground, enabling gravity flow of liquid into the secondary dehydration tank; by setting the slope of the conveying pipeline, it is convenient for liquid to flow into the secondary dehydration tank by gravity.

[0053] In this embodiment, the secondary dehydration tank is a horizontal container with baffles inside to further separate the cut-out oily wastewater. The VOC-containing waste gas is connected to an oil and gas recovery unit or a co-incinerator to treat the escaping combustible and toxic gases. The oily waste is pumped back to the tank in a closed system, while the wastewater is pumped to the sewage network in a closed system.

[0054] The working process of the closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration in this embodiment, which includes the structure of the above embodiment, is as follows: An automatic closed-loop water-cutting device 2 is added to the atmospheric pressure storage tank 1. The automatic closed-loop water-cutting device 2 can be of the liquid column resonance type, ultrasonic type, capacitive type, etc., to achieve automatic closed-loop water cutting of the atmospheric pressure storage tank. Oily wastewater is transported to the newly added secondary dehydration tank through a conveying pipeline. The secondary dehydration tank is equipped with a baffle to separate the oily wastewater into an oil phase and a water phase. Level gauges are installed in the oil phase area and the water phase area respectively, and the water pump and oil pump are interlocked for start and stop. The secondary dehydration tank is equipped with a pressure transmitter, which regulates the nitrogen and oil / gas pressures separately via the first pneumatic valve 16 and the second pneumatic valve 17. A flame arrester is installed on the exhaust pipe 6 to ensure system safety. Ultimately, the VOCs-containing oil / gas is transported to existing treatment facilities or co-processed with an incinerator. The recovered oil from the secondary dehydration tank is pumped to an existing atmospheric pressure storage tank or downstream production unit. The wastewater from the secondary dehydration tank is pumped to the existing sewage network, ensuring a completely closed-loop transport of the water, gas, and oil phases during the water-cutting process, enabling VOCs-containing oil / gas recovery and treatment. The secondary separation technology after the closed-loop water-cutting in the atmospheric pressure storage tank achieves the organic separation, collection, and treatment of the water, oil, and gas phases. It also achieves an automated and green upgrade of the closed-loop water-cutting system in the atmospheric pressure storage tank, enabling efficient oil-water separation, reducing environmental pollution risks, and ensuring safe and reliable operation of the production process.

[0055] In the description of this utility model, it should be understood that the terms "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0057] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0058] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration, characterized in that, The system includes at least one atmospheric pressure storage tank, a pipeline-type automatic shut-off water cutter, and a secondary dehydration tank. The bottom sidewall of each atmospheric pressure storage tank is connected to and communicates with the top sidewall of the secondary dehydration tank via a conveying pipeline. The pipeline-type automatic shut-off water cutter is installed on the conveying pipeline. The secondary dehydration tank is divided into an aqueous phase region and an oil phase region by a partition. The aqueous phase region is connected to and communicates with the tank area sewage network and the tank area exhaust gas treatment device via a drainage pipeline and an exhaust pipeline, respectively. The oil phase region is connected to and communicates with the top sidewall of the atmospheric pressure storage tank or a downstream production device via an oil discharge pipeline. A nitrogen conveying pipeline and a pressure transmitter are connected to the top of the secondary dehydration tank.

2. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The aqueous phase area of ​​the secondary dehydration tank is connected to a first level gauge, and a water pump is installed on the drain pipe. The first level gauge is connected to the water pump and interlocks to start and stop the water pump.

3. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The oil phase area of ​​the secondary dehydration tank is connected to a second level gauge, and an oil pump is installed on the oil discharge pipeline. The second level gauge is connected to the oil pump and interlocks to start and stop the oil pump.

4. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The partition is vertically fixed to the inner wall of the secondary dehydration tank, and an overflow gap is reserved between the partition and the top of the secondary dehydration tank.

5. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, One end of the conveying pipeline extends into the secondary dehydration tank from the top side wall and is arranged near the bottom; one end of the oil discharge pipeline extends into the secondary dehydration tank from the top and is arranged near the bottom.

6. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The nitrogen delivery pipe is equipped with a first pneumatic valve, and the pressure transmitter is connected to the first pneumatic valve.

7. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The exhaust pipe is equipped with a second pneumatic valve, a fan, a first flame arrester, and a second flame arrester. The exhaust pipe upstream of the fan is equipped with the second pneumatic valve and the first flame arrester, and the exhaust pipe downstream of the fan is equipped with the second flame arrester.

8. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The delivery pipeline is equipped with a first manual valve and a third pneumatic valve. The first manual valve is located on the delivery pipeline upstream of the automatic closed-loop water cutter, and the third pneumatic valve is located on the delivery pipeline downstream of the automatic closed-loop water cutter.

9. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The secondary dehydration tank is a horizontal tank located underground, while the atmospheric pressure storage tank and the pipeline-type automatic sealed water cutter are both located above ground. Part of the conveying pipeline is located above ground, and another part is located underground. The slope of the conveying pipeline is greater than or equal to 3‰.

10. The closed-loop water-cutting device for atmospheric pressure storage tanks capable of secondary dehydration according to claim 1, characterized in that, The secondary dehydration tank, conveying pipeline, drainage pipeline, oil discharge pipeline, and exhaust pipeline are all equipped with heat tracing cables.

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