Cryogenic full containment tank

Abstract

A cryogenic full containment tank, comprising an outer tank (11), an inner tank (12), a suspended deck (16), a heat preservation and insulation system, and a discharging pump column (15), and being further provided with a safety extraction system (14). The safety extraction system (14) comprises an extraction device (141), a filtration device (142), a liquid level detector (146) and a controller (147). The extraction device (141) passes through the top of the outer tank (11) and extends into a hot corner region (132) at the bottom through an interlayer space (13) between the inner tank (12) and a tank wall of the outer tank (11). Once leakage occurs at the inner tank (12), liquid collected at the hot corner region (132) can be extracted, and the extraction flow rate of the liquid is greater than the leakage flow rate required by leak protection standards. The filtration device (142) is arranged on a top platform of the outer tank (11), is connected between the extraction device (141) and the inner tank (12), and can filter extracted liquid and then send the filtered liquid back to the inner tank (12) or output the filtered liquid outwards. In the cryogenic full containment tank, when leakage occurs at the inner tank (12), the safety extraction system (14) can control the liquid level of the liquid leaked into the hot corner region (132) at the bottom of the interlayer space (13) from the inner tank (12) to an extremely low level that does not affect the safety of a storage tank for a long time, the extracted liquid is subjected to impurity removal by means of the filtration device (142), and then sent back to the inner tank (12) and outputted outwards.

Description

Low temperature full containment tank

[0001] This application claims priority to Chinese patent application No. 202410125561.8, filed on January 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the technical field of cryogenic liquefied gas storage, and in particular to a cryogenic full-containment tank. Background Art

[0003] Cryogenic full-containment storage tanks are the primary equipment for storing liquefied gases such as liquefied natural gas (methane), ethylene, ethane, propylene, propane, butene, and liquid ammonia. They are widely used in the petrochemical, energy, and chemical industries and are crucial for ensuring national production and energy supply. Because most of the materials stored in cryogenic full-containment tanks are flammable, explosive, or toxic and hazardous substances, and their capacities currently range from tens of thousands to over two hundred thousand cubic meters, the consequences of a leak are extremely serious.

[0004] Currently, the technical standards for the design and construction of cryogenic storage tanks require that in the event of a leak in the inner tank, the outer tank must be able to withstand the cryogenic liquid leaking from the inner tank and seal the evaporated gas to achieve orderly and controllable discharge. However, the current specifications for the design requirements of cryogenic storage tanks are not rigorous. If a leak occurs in the inner tank and the material cannot be transferred in time to reduce the inner tank liquid level to below the height of the hot corner protection structure (hot corner area), the liquid level in the annular space between the inner and outer tanks may exceed the hot corner protection height. At this time, the safe operation or safe shutdown of the cryogenic tank is difficult to ensure.

[0005] Public content

[0006] The present application provides a cryogenic full-containment tank, which includes an outer tank, an inner tank and a suspended ceiling arranged inside the outer tank, a discharge pump column for discharging liquid in the inner tank to the outside, a thermal insulation system for thermally insulating the cryogenic full-containment tank, and a safety extraction system; the inner peripheral side wall of the outer tank and the outer peripheral side wall of the inner tank enclose a mezzanine space;

[0007] The safety extraction system comprises:

[0008] an extraction device, which is in communication with the hot corner area at the bottom of the interlayer space and extends upward from the bottom of the interlayer space and through the top of the outer tank, and is used to extract liquid leaking from the inner tank into the hot corner area; the extraction flow rate of the extraction device is greater than the maximum flow rate corresponding to the leakage condition required by the design specifications;

[0009] A filtering device is provided at the top of the outer tank; the filtering device is connected between the extraction device and the inner tank, and is used to filter the liquid extracted by the extraction device and transport the filtered liquid back to the inner tank or output it to the outside.

[0010] Compared with the prior art, the extraction device of the safety extraction system of the full-containment tank provided by the present application can extract the liquid leaked from the inner tank into the hot corner area at the bottom of the interlayer space when the inner tank leaks, and its extraction flow rate is greater than the maximum flow rate corresponding to the leakage working condition required by the design specifications to control the liquid level in the hot corner area of ​​the interlayer space; and the extracted liquid is filtered by the filtering device and then transported back to the inner tank or transported to the outside to ensure that the liquid transported back to the inner tank or the liquid transported to the outside is free of impurities. In this way, the low-temperature full-containment tank with a leaking inner tank can be maintained in operation for a long time without the need to use other empty tanks to empty the materials, which buys time for transferring materials and safely shutting down. That is, the present application can enable the low-temperature full-containment tank to maintain long-term controllable and safe operation by starting the safety extraction system after the inner tank leaks without the need for emergency rescue until the materials are unloaded. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic structural diagram of a low-temperature full-containment tank in this embodiment.

[0012] FIG2 is a schematic diagram of the structure of a cryogenic full containment tank in some embodiments.

[0013] FIG3 is a schematic structural diagram of a modified embodiment of the low-temperature full containment tank shown in FIG2 .

[0014] FIG4 is a schematic structural diagram of a cryogenic full containment tank in some other embodiments.

[0015] FIG5 is a schematic structural diagram of a modified embodiment of the low-temperature full containment tank shown in FIG4 .

[0016] Implementation of the present disclosure

[0017] This application provides a cryogenic full containment tank. To make the purpose, technical solution, and effects of this application more clear and explicit, the application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain this application and are not intended to limit this application.

[0018] Currently, the most widely used full containment tank, the type of cryogenic storage tank with the highest safety rating, was introduced in the 1980s. Whether bimetallic or concrete, the height of the thermal protection features (hot corners) in these full containment tanks is typically only 5 meters. If a leak occurs in the inner tank and there is no time to drain the contents to lower the liquid level, the liquid level in the annular space between the inner and outer tanks will exceed the height of the thermal protection features, causing a high rate of evaporation (especially in metal outer tanks) and damage to the outer tank (especially concrete outer tanks).

[0019] For bimetallic outer tanks, while the tank wall material can withstand low temperatures, cryogenic liquid leaking into the annular space directly contacts the metal outer tank. Due to the metal's strong thermal conductivity, the cryogenic liquid inevitably undergoes rapid flash vaporization. Simultaneously, the infiltration of the cryogenic liquid into the pearlescent sand filler negates its cooling effect, significantly increasing the evaporation rate of the cryogenic liquid in the inner tank. The overpressure relief facility does not account for the possibility of the rapidly evaporating gas carrying large amounts of pearlescent sand, raising significant questions about its safe and effective operation during an emergency. If the overpressure relief line becomes clogged with pearlescent sand, the pressure within the tank will rapidly rise, triggering ruptures in weak links and leakage of the medium gas, leading to explosions and fires. Furthermore, the rapid vaporization of the cryogenic liquid in the annular space, coupled with the flow resistance of the insulation material, will cause a localized pressure increase in the annular space, posing a risk of external pressure instability in the upper portion of the inner tank where no liquid is stored.

[0020] For prestressed concrete outer tanks, the inner wall of the outer tank is sealed with a conventional low-alloy steel liner. Under normal operation, the outer tank's inner wall temperature remains constant and is significantly higher than the inner tank's temperature, thanks to the pearlescent sand's primary insulation function. However, if cryogenic liquid leaks into the annular space, the pearlescent sand, soaked by the liquid, loses its insulating properties. Furthermore, the pearlescent sand not directly immersed in the liquid will also be wetted by capillary action for a considerable period, significantly reducing its insulating capacity. Therefore, if the inner tank leaks and the liquid level in the annular space exceeds the thermal protection height, the lining of the concrete outer tank's inner wall will shrink rapidly due to the cryogenic liquid, becoming brittle and likely developing multiple cracks in the welds, rendering the original air- and liquid-tight properties ineffective. Cryogenic liquid that penetrates the gap between the concrete tank wall and the liner rapidly vaporizes, further tearing the liner's welds and even causing the liner to fall off. Direct contact with the cryogenic liquid can lead to frost cracking of the concrete tank wall and subsequent leakage, significantly increasing the risk of fire and explosion. For concrete tank-type cryogenic storage tanks, there is also the risk of local pressure increase caused by rapid vaporization of liquid in the annular space and instability of the upper tank wall under external pressure.

[0021] Therefore, once the inner tank of a cryogenic full-containment tank leaks and the liquid level in the annular space is higher than the height of the thermal corner protection facility, it will be difficult to operate safely regardless of whether it is a bimetallic tank type or a concrete tank type.

[0022] Article 7.2.2.1 of the EU cryogenic tank standard EN14620-1 provides the requirement that the leakage rate of a Φ20 equivalent hole at the bottom of the tank wall should be considered in case of severe leakage of the inner tank. Based on this rule, the maximum possible leakage rate set by the standard can be calculated. For 20,000 to 40,000 m 3 For storage tanks with the same specifications, the highest liquid level in the inner tank is generally in the range of 25 to 30m; 50000m 3 For the above-mentioned tanks, the highest liquid level in the tank is generally in the range of 30-35m. Based on the 30m liquid level, the leakage rate of the Φ20 aperture will reach about 27m 3 / h. The annular gap between the inner and outer tanks is generally around 1000mm. The height of the thermal corner protection facility is generally 5m. The insulation layer between it and the inner wall of the outer tank will occupy a thickness of 200-300mm. Therefore, the annular gap width between the thermal corner protection facility and the inner tank wall is about 700mm. Based on the inner tank diameters of 48m, 57m, 70m, and 80m (corresponding to the specifications of 50,000, 80,000, 120,000, and 160,000 cubic meters respectively) and an annular gap width of 700mm, the annular gap volume of the thermal corner protection facility is approximately 535, 634, 777, and 887m3 respectively. 3 If the leakage flow is 27m 3 / h, the time required to fill the 5m high thermal angle protection annular gap is approximately 19.8, 23.5, 28.8 and 32.9 hours respectively (if calculated based on a half-tank liquid level of 15m, it is approximately 28 to 45 hours). This shows that if the maximum leakage situation set by the EN14620 standard occurs, the leakage at the 30m liquid level in the inner tank will fill the thermal angle protection annular gap in about one day (no more than two days at a 15m liquid level). If there are no other storage tanks with sufficient space nearby to store the same material and transfer the tank in time, or if the liquid level in the tank is high when the accident occurs, it will take more than two days even if there is a place to transfer the material. In this case, it is inevitable that the leaked material level will exceed the thermal angle protection height, and the tank will face a very dangerous state.

[0023] It can be seen that once a major leak occurs in the existing cryogenic full-containment tank, the thermal corner protection facilities can provide operators with very limited time for safety rescue and troubleshooting. As the tank capacity continues to expand, the time required to empty the tank is getting longer and longer. Large cryogenic tanks, which are used as storage equipment in the raw material tank area of ​​receiving stations or large petrochemical enterprises, require small flow rates for transportation by tank trucks or small inland vessels, as well as for supplying materials to production equipment. The output capacity of the configured discharge pump column is almost inadequate compared to the demand for emergency tank emptying. Faced with the rapidly rising liquid level in the thermal corner protection annular gap, the tank will be helpless, and there is indeed a risk that the tank will be difficult to shut down safely.

[0024] Therefore, the present disclosure provides a full-containment tank with higher safety performance to solve the above problems and reduce safety hazards.

[0025] The specific embodiment of the low-temperature full-containment tank of the present application is described in detail below with reference to the accompanying drawings.

[0026] FIG1 is a schematic structural diagram of a low-temperature full-containment tank in this embodiment.

[0027] Referring to Figure 1 , the cryogenic full-containment tank includes an outer tank 11, an inner tank 12, a discharge pump column 15, a suspended ceiling 16, a thermal insulation system, and a safety extraction system 14. Safety extraction system 14 includes an extraction device 141 and a filtration device 142. Extraction device 141 is connected to the bottom of the interlayer space 13 and extends upward from the bottom of the interlayer space 13 through the top of the outer tank 11. Filter device 142 is located at the top of the outer tank 11 and connects the extraction device to the inner tank 12.

[0028] The present application sets up a safety extraction system 14. When the inner tank 12 leaks, the extraction device 141 can extract the liquid that leaks from the inner tank 12 into the bottom of the interlayer space 13. The extraction flow rate is greater than the maximum flow rate corresponding to the leakage condition required by the design specifications, so as to control the liquid level in the interlayer space 13 so that the liquid level in the interlayer space 13 is always below the safety warning level 133 in the hot corner area 132. In addition, the extracted liquid is filtered by the filter device 142 and then transported back to the inner tank 12 or output to the outside, so as to ensure that the liquid transported back to the inner tank 12 or output to the outside is free of impurities. In this way, the cryogenic full-containment tank with a leak in the inner tank 12 can be maintained in operation for a long time without the need to use other empty tanks to empty the material, thereby buying time for transferring materials and safely shutting down the tank. That is, the present application can enable the cryogenic full-containment tank to maintain long-term controllable and safe operation by activating the safety extraction system 14 after a leak in the inner tank 12, without the need for emergency rescue. Until the material is unloaded, the tank can be discharged.

[0029] The outer tank 11 is hollow. The inner tank 12 is disposed inside the outer tank 11 with a gap between the outer peripheral sidewall of the inner tank 12 and the inner peripheral sidewall of the outer tank 11. The inner tank 12 is used to contain liquefied gases such as liquefied natural gas (methane), ethylene, ethane, propylene, propane, butene, and liquid ammonia.

[0030] The inner circumferential sidewalls of the outer tank 11 and the outer circumferential sidewalls of the inner tank 12 enclose an interlayer space 13. Interlayer space 13 is divided vertically into an insulation zone 131 and a hot corner zone 132. The insulation zone 131 is provided with an insulation layer to keep the inner tank 12 cool and prevent the low-temperature liquid inside from evaporating. The hot corner zone 132 is divided from bottom to top into a lower portion, a middle portion, and an upper portion. The lower portion is a liquid collection area 1321, the middle portion is a safe zone 1322 for liquid level fluctuations during extraction operations, and the upper portion is an isolation zone 1323 separated from the insulation zone 131. A safety warning level 133 is located in the upper portion, separated from the junction of the middle and upper portions. It should be noted that the upper portion is where the liquid level should not reach during normal operation of the safety extraction system 14. If the liquid level reaches the safety warning level 133, it indicates that the extraction rate is less than the leakage rate and the extraction volume needs to be increased. A heat insulation layer is provided in the hot corner area 132 , and the heat insulation layer is provided in close contact with the inner wall of the outer tank 11 .

[0031] When the inner tank 12 leaks, the lower part is the leaked liquid collection area 1321, and the middle part is the liquid level fluctuation safety area 1322 of the leaked liquid. At this time, the safety extraction system 14 is used to ensure that the liquid level in the hot corner area 132 is below the safety warning liquid level 133 to prevent the low-temperature liquid leaking into the hot corner area 132 from contacting the pearlescent sand located in the insulation area 131, thereby preventing the heat insulation and cold preservation effect of the pearlescent sand from failing.

[0032] The discharge pump column 15 passes through the inner tank 12 and the outer tank 11 from bottom to top, and extends upward from the top of the outer tank 11. The discharge pump column is used to discharge the liquid in the inner tank 12 to the outside. Specifically, the discharge pump column 15 includes a discharge pipe and a discharge pump arranged inside the discharge pipe. The liquid inlet of the discharge pipe is connected to the bottom of the inner tank 12, and the discharge pipe passes through the top of the inner tank 12 and the outer tank 11 in the vertical direction. There is a vertical gap between the liquid inlet of the discharge pipe and the bottom of the inner tank 12, so that the liquid in the inner tank 12 can enter the discharge pipe through the liquid inlet of the discharge pipe. A discharge pipeline 151 is connected to the liquid outlet of the discharge pipe. The discharge pipeline 151 is used to communicate with the outside, and the material transportation to the outside can be achieved through the discharge pipeline 151.

[0033] The discharge pump is arranged inside the discharge pipe and is connected to the bottom of the inner tank 12. The discharge pump is used to provide power to pump the liquid in the inner tank 12 into the discharge pipe and transport it outward through the discharge pipe.

[0034] The suspended ceiling 16 is provided inside the outer tank 11 and is located above the inner tank 12. Specifically, the suspended ceiling 16 is connected to the top wall inside the outer tank 11.

[0035] The thermal insulation system is used to insulate the low-temperature full-containment tank. It includes a ceiling insulation layer, a mezzanine insulation layer, and a bottom insulation layer. The mezzanine insulation layer is the aforementioned insulation layer located within insulation zone 131 and within hot corner zone 132. Each insulation layer is composed of one or more materials, such as pearlescent sand, elastic felt, thermal insulation cotton, and foam glass bricks, and is used to insulate the inner tank 12.

[0036] The following is a detailed description of the safety extraction system 14 in this embodiment.

[0037] The safety extraction system 14 includes an extraction device 141 , a filtering device 142 , a liquid level detector 146 and a controller 147 .

[0038] The extraction device 141 is connected to the hot corner area 132 at the bottom of the interlayer space 13. The extraction device 141 extends upward from the bottom of the interlayer space 13 and passes through the top of the outer tank 11. The extraction device 141 is used to extract liquid that leaks from the inner tank 12 into the hot corner area 132 to control the liquid level in the interlayer space 13. Specifically, the extraction device 141 is connected to the lower portion of the hot corner area 132, that is, the extraction device 141 is connected to the liquid collection area 1321.

[0039] The extraction flow rate of the extraction device 141 is greater than the maximum possible leakage flow rate of the inner tank 12 protected by the standard, and can control the liquid level of the cryogenic liquid leaking into the hot corner area 132 within the safe area 1322 when a leakage accident occurs in the inner tank 12. For example, taking the cryogenic full containment tank with a liquid level of 30m and an equivalent leakage aperture of Φ20 as an example, the leakage rate will reach about 27m 3 / h, at this time, the extraction flow rate of the extraction device 141 should be greater than 27m 3 / h.

[0040] In this embodiment, the extraction device 141 is a specially made small pump column. Specifically, the extraction flow rate of the small pump column 141 is smaller than the discharge flow rate of the discharge pump column 15 conventionally configured in a low-temperature full-capacity tank, and the inner diameter of the pump barrel is smaller than the inner diameter of the discharge pipe.

[0041] The extraction device 141 includes a pump barrel and a cryogenic submersible pump.

[0042] The liquid inlet of the pump barrel is located in and communicates with the hot corner area 132. The pump barrel extends vertically upward and passes through the top of the outer tank 11, so that its liquid outlet is located above the outer tank 11. Specifically, the liquid inlet of the pump barrel is located at the lower part of the hot corner area 132 and communicates with the liquid collection area 1321. There is a vertical gap between the liquid inlet of the pump barrel and the bottom wall of the outer tank 11, so that the liquid in the hot corner area 132 can enter the pump barrel through the liquid inlet.

[0043] The cryogenic submersible pump is disposed inside the pump barrel and is in communication with the hot corner area 132 . The cryogenic submersible pump is used to provide power to draw the liquid in the hot corner area 132 into the pump barrel and transport it through the pump barrel.

[0044] FIG2 is a schematic diagram of the structure of a cryogenic full containment tank in some embodiments.

[0045] With reference to FIG2 , it should be noted that the embodiment shown in FIG2 is identical to the embodiment shown in FIG1 in terms of other structures, including the outer tank 11, inner tank 12, interlayer space 13 and its insulation area 131 and hot corner area 132, discharge pump column, and ceiling 15. For reference, the above description is provided and will not be further elaborated here. Furthermore, the embodiment shown in FIG2 differs from the embodiment shown in FIG1 in terms of the safety extraction system 14. These differences will be explained below with reference to FIG2 .

[0046] In some embodiments, the extraction device 241 includes an extractor 2411 , a circulation pump 2412 , a liquid inlet line 2413 , and an outlet line 2414 .

[0047] The extractor 2411 is provided in the hot corner area 132. The suction port of the extractor 2411 is communicated with the hot corner area 132, and the liquid outlet of the extractor 2411 is communicated with the liquid inlet of the filter device 242. In this embodiment, the extractor 2411 is a Venturi pump.

[0048] There may be multiple extractors 2411 , and multiple extractors 2411 are arranged in series, as shown in FIG3 .

[0049] The circulation pump 2412 is provided at the top of the outer tank 11. The liquid inlet of the circulation pump 2412 is connected to the filter device 242, and the liquid outlet of the circulation pump 2412 is connected to the liquid inlet of the extractor 2411, for pumping liquid into the extractor 2411 to realize the extraction operation of the extractor 2411.

[0050] One end of the liquid inlet line 2413 is connected to the liquid outlet of the circulation pump 2412. The other end passes through the top of the outer tank 11, enters the interlayer space 13, and extends downward to the lower portion of the hot corner area 132 of the interlayer space 13. It is connected to the liquid inlet of the extractor 2411, thereby connecting the liquid outlet of the circulation pump 2412 with the liquid inlet of the extractor 2411. Optionally, a third control valve 246 is provided on the liquid inlet line 2413 for controlling its on / off function.

[0051] One end of the output pipe 2414 is connected to the liquid outlet of the extractor 2411 , and the other end extends upward and passes through the top of the outer tank 11 and is connected to the liquid inlet of the filtering device 242 .

[0052] When extracting the liquid in the interlayer space 13, the liquid in the filter device 242 enters the extractor 2411 through the circulation pump 2412 and the liquid inlet pipe 2413, so that the liquid in the hot corner area 132 of the interlayer space 13 can enter the extractor 2411 through the suction hole under the action of the pressure difference, and after mixing, enter the filter device 242 through the output pipe 2414.

[0053] FIG4 is a schematic structural diagram of a cryogenic full containment tank in some other embodiments.

[0054] Referring to FIG4 , it should be noted that the embodiment shown in FIG4 is identical to the embodiment shown in FIG1 in terms of other structures, including the outer tank 11, inner tank 12, interlayer space 13 and its insulation area 131 and hot corner area 132, discharge pump column, and ceiling 15. For reference, the above description can be used and will not be further elaborated here. Furthermore, the embodiment shown in FIG4 differs from the embodiment shown in FIG1 in terms of the safety extraction system 14. These differences will be explained below with reference to FIG4 .

[0055] 4 , in some other embodiments, the extraction device 341 includes an extractor 3411 , a power pump column 3412 , a liquid inlet pipeline 3413 , and an output pipeline 3414 .

[0056] The extractor 3411 is disposed at the bottom of the interlayer space 13 . The suction port of the extractor 3411 is communicated with the interlayer space 13 , and the liquid outlet of the extractor 3411 is communicated with the liquid inlet of the filter device 342 .

[0057] There may be multiple extractors 3411 , and the multiple extractors 3411 are arranged in series, as shown in FIG5 .

[0058] The liquid inlet of the power pump column 3412 communicates with the inner tank 12, and the liquid outlet of the power pump column 3412 communicates with the liquid inlet of the extractor 3411, thereby pumping liquid into the extractor 3411 to perform the extraction operation of the extractor 3411. Specifically, the power pump column 3412 passes through the ceiling 15 of the inner tank 12 and the outer tank 11 from bottom to top, and extends upward from the top of the outer tank 11, so that the liquid outlet of the power pump column 3412 is located above the outer tank 11.

[0059] Optionally, the power pump column 3412 includes a feed pipe and a power pump disposed inside the feed pipe. The liquid inlet of the feed pipe is connected to the bottom of the inner tank 12, and there is a vertical gap between the liquid inlet of the feed pipe and the bottom of the inner tank 12, so that the liquid in the inner tank 12 can enter the feed pipe through the liquid inlet of the feed pipe. The feed pipe passes vertically upward through the ceiling 15 of the inner tank 12 and the top of the outer tank 11, and the liquid outlet of the feed pipe is connected to the liquid inlet of the extractor 3411. The power pump is disposed inside the feed pipe and is connected to the inner tank 12. The power pump is used to provide power to draw the liquid in the inner tank 12 into the feed pipe, and then transport it to the extractor 3411 through the feed pipe.

[0060] It should be noted that the power pump column 3412 refers to the feed pump column 15, that is, the discharge pump column 15 in this embodiment also serves as the power pump column 3412 of the extraction device 341. At this time, the liquid outlet of the discharge pump column 15 is connected to the liquid inlet of the extractor 3411. The extractor 3411 uses the discharge pump column 15 configured for the low-temperature full-containment tank during normal production operations as a power source to provide power to the extractor 3411 to extract liquid that leaks from the inner tank 12 into the bottom of the interlayer space 13.

[0061] In other embodiments, a power pump column 3412 independent of the discharge pump column 15 may be provided as a power source.

[0062] One end of the liquid inlet line 3413 is connected to the liquid outlet of the power pump column 3412, and the other end passes through the top of the outer tank 11 into the interlayer space 13, and extends downward to the lower part of the hot corner area 132 of the interlayer space 13, and is connected to the liquid inlet of the extractor 3411, thereby realizing the connection between the liquid outlet of the power pump column 3412 and the liquid inlet of the extractor 3411. Specifically, the liquid inlet line 3413 is connected to the liquid outlet of the discharge pump column 15. At this time, the liquid outlet of the power pump column is located above the outer tank, which facilitates the connection between the liquid inlet line 3413 and the liquid outlet of the power pump column 3412, and facilitates the maintenance of the connection between the two. Optionally, a third control valve 346 is provided on the liquid inlet line 3413 for controlling its on and off.

[0063] One end of the output pipe 3414 is connected to the liquid outlet of the extractor 3411 , and the other end extends upward and passes through the top of the outer tank 11 and is connected to the liquid inlet of the filter device 342 .

[0064] When extracting the liquid in the interlayer space 13, the liquid in the inner tank 12 enters the extractor 3411 through the power pump column 3412 (discharge pump column 15) and the liquid inlet pipeline 3413, so that the liquid in the hot corner area 132 of the interlayer space 11 can enter the extractor 3411 through the suction hole under the action of the pressure difference, and after mixing, enter the filtering device 342 through the output pipeline 3414.

[0065] Continuing to refer to FIG. 1 , in this embodiment, the filter device 142 includes a filter tank and a filter element disposed inside the filter tank.

[0066] The filter tank body is provided with a liquid inlet and a return port, both communicating with the interior thereof. The liquid inlet is connected to the liquid outlet of the extraction device 141, while the return port is connected to the inner tank 12. Specifically, the liquid inlet is located at the top of the filter tank body and communicates with the pump barrel via a liquid inlet line 1431. The return port is located at the bottom of the filter tank body and communicates with the inner tank 12 via a return line 1432.

[0067] Optionally, a first control valve 144 is provided on the return line 1432 for controlling the on-off of the return line.

[0068] The filter tank is also provided with an infusion port, located at the bottom of the filter tank, which communicates with the outside via a delivery line 1433. Optionally, a second control valve 145 is provided on delivery line 1433 to control its on / off function. In other embodiments, a reflux port can also be connected to the outside via delivery line 1433.

[0069] Referring to Figure 2 , in some embodiments, the reflux port is located at the lower portion of the filter tank. Optionally, the reflux port overlaps with the infusion port. Specifically, the delivery line 2432 is connected to the infusion port, and the reflux line 2431 is connected to the delivery line 2432. The connection point between the reflux line 2431 and the delivery line 2432 is located between the second control valve 245 and the filter tank.

[0070] In some embodiments, the filter tank is further provided with a communication port communicating with its interior, which is connected to the liquid inlet of the extraction device 241. Optionally, the communication port is the reflux port in the embodiment shown in Figure 1, and the communication port is connected to the circulation pump 2412 through a pipeline.

[0071] 4 , in some other embodiments, the liquid inlet of the filter tank is connected to the output pipeline 3414 .

[0072] Referring to Figure 1 , the filter element is disposed within the filter tank body, dividing the interior of the filter tank body into a space to be filtered and a storage space along the upper and lower sides, with the liquid inlet and reflux port located on opposite sides of the filter element. The liquid inlet communicates with the space to be filtered, while the reflux port and the liquid inlet both communicate with the storage space. Liquid extracted by the extraction device 141 enters the space to be filtered through the liquid inlet, where impurities are blocked by the filter element above, filtering the liquid within the space to be filtered. The filtered liquid then flows down to the storage space and back into the inner tank 12 through the reflux port and reflux line 1432. Alternatively, the filtered liquid can be transported externally through the infusion port and delivery line 1433.

[0073] Referring to Figure 2 , the communication port, the reflux port, and the infusion port are located on the same side of the filter element, wherein the communication port communicates with the accommodating space. At this point, liquid extracted by the extraction device 241 enters the filtration space through the liquid inlet. The filter element blocks impurities above it, thereby filtering the liquid in the filtration space. The filtered liquid then flows down to the accommodating space and can be transported to the circulation pump 2412 through the communication port and pipeline. Simultaneously, it can flow back into the inner tank 12 through the reflux port and reflux pipeline 2431. Alternatively, the filtered liquid can be transported outward through the infusion port and delivery pipeline 2432.

[0074] 1 , the filter tank body is optionally provided with a cleaning port 1421 communicating with the interior of the filter tank body. Specifically, the cleaning port 1421 is located at the upper portion of the filter tank body and above the filter element. Impurities on the filter element can be cleaned through the cleaning port 1421 to ensure the filtering effect of the filter element.

[0075] In other embodiments, the filter device 142 may also be other forms of components, such as a pipe filter, etc., which is not limited here, and the specific configuration depends on the needs.

[0076] The liquid level detector 146 is used to detect the liquid level signal of the interlayer space 13 and output the liquid level signal. Optionally, the liquid level detector 146 can detect the liquid level at the bottom of the interlayer space 13 in a contact or non-contact manner. Specifically, the liquid level detector 146 is used to detect the liquid level at the bottom of the hot corner area 132.

[0077] Controller 147 is electrically connected to extraction device 141 and liquid level detector 146. Controller 147 receives liquid level signals and controls the opening and closing of extraction device 141 based on the liquid level signals. Furthermore, controller 147 is electrically connected to first control valve 144 and second control valve 145 to control their opening and closing, as well as their degree of opening. Specifically, controller 147 is electrically connected to a cryogenic submersible pump.

[0078] The controller 147 has the functions of monitoring the liquid level and giving an alarm, and issues an alarm signal when the monitored liquid level is higher than the set warning liquid level.

[0079] The controller 147 has a first liquid level preset value, a second liquid level preset value and a third liquid level preset value set in sequence from low to high, wherein the first liquid level preset value indicates that a liquid level appears in the hot corner area 132 and liquid accumulation is formed, the second liquid level preset value is the liquid level for closing the extraction device 141, and the third liquid level preset value is the liquid level for starting the extraction device 141. At this time, the vertical spacing between the liquid inlet of the pump barrel and the bottom wall of the outer tank 11 is smaller than the liquid level height represented by the second liquid level preset value.

[0080] In the embodiment shown in FIG2 , the controller 248 is electrically connected to the circulation pump 2412. When the circulation pump is activated at the third preset liquid level value, the vertical spacing between the suction port of the extractor 2411 and the bottom wall of the outer tank 11 is less than the liquid level indicated by the second preset liquid level value.

[0081] In the embodiment shown in FIG4 , controller 348 is electrically connected to power pump column 3412 (discharge pump column 15). The controller is also electrically connected to third control valve 346 to control the opening and closing and degree of opening of third control valve 346. When third control valve 346 is opened at the third preset liquid level, the vertical spacing between the suction port of extractor 3411 and the bottom wall of outer tank 11 is less than the liquid level indicated by the second preset liquid level.

[0082] Referring to Figure 1 , controller 147 is electrically connected to liquid level detector 146 to receive liquid level signals. When the liquid level reaches a first preset level, controller 147 issues an alarm signal to alert personnel. It should be noted that other technologies can detect and issue an alarm at an early stage of leakage in hot corner 132, even before a liquid level has formed. The alarm signal issued by controller 147 when the liquid level in hot corner 132 reaches the first preset level is intended to indicate that the safety extraction system 14 may be activated, and is not intended to detect whether there is a leak in the inner tank 12.

[0083] The working principle of the above-mentioned safe extraction systems 14, 24, and 34 is as follows:

[0084] In the embodiment shown in FIG1 , the liquid level detector 146 can detect the liquid level signal in the hot corner 132 of the interlayer space 13 in real time using either contact or non-contact methods, and display and upload the signal locally to the controller 147. When the liquid level signal detected by the liquid level detector 146 is greater than or equal to a first preset liquid level value, it indicates that the inner tank 12 is leaking and liquid has accumulated in the hot corner 132. At this point, the controller 147 receives the liquid level signal and issues an alarm.

[0085] When the liquid level signal received by the controller 147 from the liquid level detector 146 reaches the third preset liquid level value for activating the extraction device 141, the controller 147 sends a control signal to control the cryogenic submersible pump of the extraction device 141 to start, and at the same time controls the first control valve 144 to open, so that the cryogenic submersible pump cooperates with the pump barrel to extract the liquid from the hot corner area 132, and transports it to the filter device 142 for filtration through the liquid inlet pipe 1431. The filtered liquid then flows back to the inner tank 12 through the return pipe 1432. When the liquid level signal detected by the liquid level detector 146 drops to the second preset liquid level value for shutting down the extraction device 141, the controller 147 sends a control signal to shut down the cryogenic submersible pump of the extraction device 141.

[0086] Alternatively, controller 147 controls the cryogenic submersible pump, first control valve 144, and second control valve 145 to open, so that the cryogenic submersible pump and the pump barrel cooperate to extract liquid from hot corner area 132 and transport it to filter device 142 for filtration through liquid inlet pipe 1431. The filtered liquid then flows back to inner tank 12 through return pipe 1432 and is simultaneously transported outward through delivery pipe 1433. When the liquid level signal detected by liquid level detector 146 drops to a second preset liquid level value for shutting down extraction device 141, controller 147 sends a control signal to shut down the cryogenic submersible pump of extraction device 141.

[0087] Alternatively, controller 147 controls the cryogenic submersible pump and opens second control valve 145, so that the cryogenic submersible pump and the pump barrel cooperate to extract liquid from hot corner area 132, and deliver it to filter device 142 for filtration through liquid inlet pipe 1431. The filtered liquid is then delivered to the outside through delivery pipe 1433. When the liquid level signal detected by liquid level detector 146 drops to a second preset liquid level value for shutting down extraction device 141, controller 147 sends a control signal to shut down the cryogenic submersible pump of extraction device 141.

[0088] In the embodiment shown in FIG2 , the liquid level detector 247 detects the liquid level signal in the hot corner region 132 of the interlayer space 13 in real time and transmits it to the controller 248. When the liquid level signal detected by the detection probe of the liquid level detector 247 is greater than or equal to a first preset liquid level value, it indicates that the inner tank 12 has leaked and liquid has accumulated in the hot corner region 132. At this point, the controller 248 receives the liquid level signal and issues an alarm.

[0089] When the liquid level signal received by the controller 248 from the liquid level detector 247 reaches the third preset liquid level value for activating the extraction device 241, the controller 248 sends a control signal to control the circulation pump 2412 and the first control valve 244 of the extraction device 241 to start, so that the circulation pump 2412 extracts the liquid in the accommodating space of the filter tank of the filtration device 242 and transports it to the extractor 2411 through the liquid inlet pipe 2413. Under the action of the pressure difference, the liquid in the hot corner area 132 of the interlayer space 13 can enter the extractor 2411 through the suction hole. After mixing, it enters the filtration device 242 through the output pipe 2414 and the liquid inlet for filtration. The filtered liquid then flows back to the inner tank 12 through the return pipe 2431. When the liquid level signal detected by the liquid level detector 247 drops to the second preset liquid level value for shutting down the extraction device 241, the controller 248 sends a control signal to shut down the circulation pump 2412 of the extraction device 241.

[0090] Alternatively, controller 248 controls circulation pump 2412, first control valve 244, and second control valve 245 to open, so that circulation pump 2412 cooperates with liquid inlet pipe 2413 to introduce liquid from the filter tank into extractor 2411. Liquid in hot corner region 132 of interlayer space 13 can enter extractor 2411 through suction holes under the action of pressure differential, and after mixing, enter filter device 242 through outlet pipe 2414 for filtration. The filtered liquid then flows back to inner tank 12 through reflux pipe 2431 and is simultaneously transported outward through delivery pipe 2432. When the liquid level signal detected by liquid level detector 247 drops to a second preset liquid level value for shutting down extraction device 241, controller 248 sends a control signal to shut down circulation pump 2412 of extraction device 241.

[0091] Alternatively, controller 248 controls circulation pump 2412 and second control valve 245 to open, so that circulation pump 2412 cooperates with liquid inlet pipe 2413 to introduce liquid from the filter tank into extractor 2411. Liquid in hot corner region 132 of interlayer space 13 can enter extractor 2411 through suction holes under the action of a pressure differential, and after mixing, enter filter device 242 through output pipe 2414 for filtration. The filtered liquid is then transported outward through delivery pipe 2432. When the liquid level signal detected by liquid level detector 247 drops to a second preset liquid level value for shutting down extractor 241, controller 248 sends a control signal to shut down circulation pump 2412 of extractor 241.

[0092] In the embodiment shown in FIG4 , the liquid level detector 347 can detect the liquid level of the hot corner area 132 of the interlayer space 13 in real time by contact or non-contact means, and transmit the signal to the controller 348. When the liquid level detected by the liquid level detector 347 is greater than or equal to the first liquid level preset value, it indicates that the inner tank 12 has leaked and liquid has accumulated in the hot corner area 132. At this time, the controller 348 issues an alarm signal. When the power pump column 3412 is used for extraction, the power pump column 3412 will be opened first, and it can transport materials to the outside. When the liquid level in the hot corner area rises to the third liquid level preset value, the control valve 346 is opened to allow a portion of the material to enter the extractor for extraction.

[0093] When the liquid level signal received by the controller 348 from the liquid level detector 347 reaches the third liquid level preset value for starting the extraction device 341, the power pump column 3412 is in the working state and extracts the liquid in the inner tank 12 and transports it outward, at this time, the controller 348 sends a control signal to control the first control valve 344 and the third control valve 346 to start, or, when the power pump column 3412 is in the closed state, the controller 348 controls the first control valve 344 and the third control valve 346 to start. In addition, it is necessary to control the activation of the power pump column 3412 so that the power pump column 3412 (discharge pump column 15) extracts the liquid from the inner tank 32 and transports it to the extractor 3411 via the liquid inlet line 3413. This allows the liquid in the hot corner area 132 of the interlayer space 13 to enter the extractor 3411 through the suction hole under the action of the pressure difference. After mixing, it enters the filter device 342 through the output line 3414 and the liquid inlet for filtration. The filtered liquid then flows back to the inner tank 32 via the return line 3431. When the liquid level signal detected by the liquid level detector 347 drops to the second liquid level preset value that shuts down the extraction device 341, the controller 348 sends a control signal to shut down the power pump column 3412 (discharge pump column 15) and / or the third control valve 346. In other words, if it is still necessary to transport material outward via the power pump column 3412, only the third control valve 346 needs to be closed.

[0094] Alternatively, the controller 348 controls the discharge pump column 15, the first control valve 344, and the third control valve 346 to open, so that the power pump column 3412 (discharge pump column 15) cooperates with the liquid introduction pipeline 3413 to introduce the liquid in the inner tank 32 into the extractor 3411. This allows the liquid in the hot corner area 132 of the interlayer space 13 to enter the extractor 3411 through the suction hole under the action of the pressure difference. After mixing, it enters the filter device 342 for filtration through the output pipeline 3414. The filtered liquid then flows back to the inner tank 32 through the return pipeline 3431 and is simultaneously transported outward through the delivery pipeline 3432. When the liquid level signal detected by the liquid level detector 347 drops to the second liquid level preset value for shutting down the extraction device 341, the controller 348 sends a control signal to close the power pump column 3412 (discharge pump column 15) and / or the third control valve 346.

[0095] Alternatively, the controller 348 controls the power pump column 3412 (discharge pump column 15) and the third control valve 346 to open, so that the power pump column 3412 (discharge pump column 15) cooperates with the liquid introduction pipeline 3413 to introduce the liquid in the inner tank 32 into the extractor 3411. This allows the liquid in the hot corner area 132 of the interlayer space 13 to enter the extractor 3411 through the suction hole under the action of the pressure difference. After mixing, it enters the filter device 342 through the output pipeline 3414 for filtration. The filtered liquid is then directly transported outward through the delivery pipeline 3432. When the liquid level signal detected by the liquid level detector 347 drops to the second preset liquid level value for shutting down the extractor 341, the controller 348 sends a control signal to close the power pump column 3412 (discharge pump column 15) and / or the third control valve 346.

[0096] In summary, the present application sets up a safety extraction system. When the inner tank leaks, the extraction device 341 can extract the liquid that leaks from the inner tank into the bottom of the interlayer space to control the liquid level in the hot corner area at the bottom of the interlayer space. Moreover, the extracted liquid is filtered by the filter device and then transported back to the inner tank or output to the outside to ensure that the liquid transported back to the inner tank or the liquid output to the outside is free of impurities. In this way, the cryogenic full-containment tank with a leaking inner tank can be maintained in operation for a long time without the need to use other empty tanks to empty the material, thus buying time for transferring materials and shutting down safely. That is, the present application can enable the cryogenic full-containment tank to maintain long-term controllable and safe operation by activating the safety extraction system after a leak accident in the inner tank, without the need for emergency rescue until the material is unloaded.

[0097] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this application, and all these changes or substitutions should fall within the scope of protection of the claims attached to this application.

Claims

1. A cryogenic full containment tank comprising an outer tank, an inner tank and a suspended ceiling disposed within the outer tank, a discharge pump column for discharging liquid from the inner tank, a thermal insulation system for thermally insulating the cryogenic full containment tank, and a safety extraction system; An inner circumferential side wall of the outer tank and an outer circumferential side wall of the inner tank enclose a sandwich space; The safety extraction system comprises: an extraction device, which is in communication with the hot corner area at the bottom of the interlayer space and extends upward from the bottom of the interlayer space and through the top of the outer tank, and is used to extract liquid leaking from the inner tank into the hot corner area; the extraction flow rate of the extraction device is greater than the maximum flow rate corresponding to the leakage condition required by the design specifications; A filtering device is provided at the top of the outer tank; the filtering device is connected between the extraction device and the inner tank, and is used to filter the liquid extracted by the extraction device and transport the filtered liquid back to the inner tank or output it to the outside.

2. The cryogenic full containment tank according to claim 1, wherein: The extraction device includes a pump barrel and a cryogenic submersible pump, wherein the liquid inlet of the pump barrel is located in the hot corner area and communicates with the hot corner area, and the pump barrel extends vertically upward and passes through the top of the outer tank; The low-temperature submersible pump is arranged inside the pump barrel and is communicated with the hot corner area. The low-temperature submersible pump is used to provide power to pump out the liquid in the hot corner area.

3. The cryogenic full containment tank according to claim 1, wherein: The extraction device includes an extractor and a circulation pump, the extractor is arranged in the hot corner area, the suction port of the extractor is communicated with the hot corner area, and the liquid outlet of the extractor is communicated with the liquid inlet of the filtration device; The circulation pump is arranged on the top of the outer tank, the liquid inlet of the circulation pump is connected to the filtering device, and the liquid outlet of the circulation pump is connected to the liquid inlet of the extractor. The circulation pump is used to pump liquid into the extractor to realize the extraction operation of the extractor.

4. The cryogenic full containment tank according to claim 1, wherein: The extraction device includes an extractor and a power pump column; The extractor is arranged at the hot corner area at the bottom of the interlayer space, the suction port of the extractor is communicated with the hot corner area, and the liquid outlet of the extractor is communicated with the liquid inlet of the filtration device; The liquid inlet of the power pump column is communicated with the inner tank, and the liquid outlet of the power pump column is communicated with the liquid inlet of the extractor, so as to pump liquid into the extractor to realize the extraction operation of the extractor.

5. The cryogenic full containment tank according to claim 4, wherein: The power pump column passes through the inner tank and the outer tank in sequence from bottom to top, and the liquid outlet of the power pump column is located above the outer tank.

6. The cryogenic full containment tank according to claim 3 or 4, wherein: The extraction device includes a plurality of extractors; A plurality of the extractors are arranged in series.

7. The cryogenic full containment tank according to claim 1, wherein: The filtering device includes a filter tank body and a filter element arranged inside the filter tank body. The filter tank body is provided with a liquid inlet and a reflux port connected to its interior, and the liquid inlet and the reflux port are arranged on opposite sides of the filter element; the liquid inlet is connected to the liquid outlet of the extraction device, the reflux port is connected to the inner tank, and the reflux port is connected to the outside.

8. The cryogenic full containment tank according to claim 7, wherein: The filter tank body is also provided with an infusion port, which is communicated with the outside through a delivery pipeline.

9. The cryogenic full containment tank according to claim 1, wherein: The filtering device includes a filter tank body and a filter element arranged inside the filter tank body. The filter tank body is provided with a liquid inlet and a communication port connected to its interior, and the liquid inlet and the communication port are arranged on opposite sides of the filter element; the liquid inlet is connected to the liquid outlet of the extraction device, and the communication port is connected to the liquid inlet of the extraction device.

10. The cryogenic full containment tank according to claim 9, wherein: The filter tank body is also provided with a reflux port and an infusion port, and the reflux port, the infusion port and the communication port are located on the same side of the filter element; the reflux port is connected to the inner tank through a reflux pipeline, and the infusion port is connected to the outside through a delivery pipeline.

11. The cryogenic full containment tank according to any one of claims 7 to 10, wherein: The filter tank body is also provided with a cleaning port communicated with the interior thereof, and the cleaning port is arranged correspondingly above the filter element.

12. The cryogenic full containment tank according to claim 1, wherein: The safety extraction system further includes a liquid level detector and a controller, wherein the liquid level detector is used to detect a liquid level signal inside the hot corner area and output the liquid level signal; The controller is electrically connected to the extraction device and the liquid level detector, and receives the liquid level signal and controls the opening and closing of the extraction device according to the liquid level signal; The controller has the functions of monitoring the liquid level and giving an alarm, and sends out an alarm signal when the monitored liquid level is higher than the set warning liquid level.

13. The cryogenic full containment tank according to claim 1, wherein: The interlayer space is divided into a heat insulation area and a hot corner area along the upper and lower sides; The hot corner area is divided into a lower part, a middle part and an upper part from bottom to top, the lower part is a liquid collection area, the middle part is a liquid level fluctuation safety area for extraction operation, and the upper part is an isolation area; The extraction device is in communication with the liquid collection area.

14. The cryogenic full containment tank according to claim 13, wherein: Insulation layers are provided in both the insulation area and the hot corner area; the insulation layer in the hot corner area is arranged closely to the inner wall of the outer tank.

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