Serpentine maintenance pipeline system for protecting thin-film tanks and thin-film tank maintenance method

Abstract

The present invention discloses a serpentine maintenance pipeline system for protecting a thin-film tank and a method for maintaining a thin-film tank, belonging to the technical field of natural gas transportation and storage. It includes a gas input end, a gas output end, and a protection pipeline. The protection pipeline is arranged to surround and wrap the outer periphery of the thin-film tank. One end of the protection pipeline is connected to the gas input end, and the other end is connected to the gas output end. The protection pipeline includes straight sections and elbow sections, which are arranged alternately with each other, and expansion joints and air vents are also provided on the straight sections or elbow sections. By adjusting the structure of the protection pipeline, the present application solves the connection problem of the existing maintenance pipeline during thermal expansion and contraction, ensures that the protection pipeline is always in an integral structure, ensures the stability of the maintenance pipeline system under different temperature conditions such as thermal expansion and contraction, guarantees the stable output of the protection gas and the stability of the discharge of the liquid cargo gas, facilitates the staff to master the working conditions of the thin-film tank, and ensures the safety of liquid cargo storage and transportation.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural gas transportation and storage, and particularly relates to a serpentine maintenance pipeline system for protecting a thin-film tank and a method for maintaining a thin-film tank. Background Art

[0002] As a clean and efficient energy source, liquefied natural gas is mainly stored and transported through cryogenic atmospheric storage tanks or pressure storage tanks. Due to its own low temperature and highly compressed state characteristics, the transportation of liquefied natural gas has high requirements for sealing and stability. Based on the transportation regulations of liquefied natural gas, it is usually required that the natural gas storage tank has a cargo containment system with a complete or partially complete secondary shielding space, and the secondary shielding space needs to be filled with dry protective gas to ensure the safety of the transportation vehicle in case of cargo leakage.

[0003] In the existing thin-film tank, the secondary shielding space mainly uses straight pipes distributed on the outer periphery of the thin-film tank, and the protective gas is transported through the straight pipes to form a protective gas atmosphere on the outer periphery of the thin-film tank. When the liquefied natural gas in the thin-film tank leaks, the low-temperature liquefied natural gas will cause thermal expansion and contraction of the straight pipes, which may cause damage to the overall pipeline. To avoid the damage problem of the protective gas pipeline under thermal expansion and contraction, the straight pipes are usually segmented and cut, and then a smaller pipe is nested between two straight pipes. One end of the smaller pipe is welded to one of the straight pipes, and the other end is sleeved in the other straight pipe. The smaller pipe can expand and contract in the straight pipe to avoid damage to the overall pipeline. However, since the overall protective gas transmission pipeline forms a multi-segment pipeline structure, this makes the protective gas leak from the joints of each straight pipe; and when natural gas leaks, the natural gas entering the secondary shielding space can also enter the inside of the protective gas pipeline from the joints of the straight pipes, and the thermal expansion and contraction of the straight pipes will cause the size of the straight pipe joint gap to change, resulting in uneven distribution of the protective gas transmission in the secondary shielding layer, or unstable gas extraction when extracting natural gas through the protective gas pipeline. Summary of the Invention

[0004] In view of one or more of the above defects or improvement requirements in the prior art, the present invention provides a serpentine maintenance pipeline system for protecting a thin-film tank to solve the problems of uneven distribution of protective gas transmission and unstable extraction of natural gas when the existing protective gas pipeline leaks natural gas.

[0005] To achieve the above object, the present invention provides a serpentine maintenance pipeline system for protecting a thin-film tank, including:

[0006] A gas input end for introducing a protective gas;

[0007] A gas output end for outputting the protective gas and / or the liquid cargo gas to the outside;

[0008] A protective pipeline is arranged around and wrapped around the outer periphery of the film tank; one end of the protective pipeline is connected to the gas input end, and the other end is connected to the gas output end;

[0009] The protective pipeline includes a straight section and a bent section, and the straight section and the bent section are alternately connected to be spirally arranged around the outer periphery of the film tank;

[0010] An expansion joint is provided on the straight section, and the expansion joint is telescopically arranged; and, air outlet holes are formed on the straight section and / or the bent section to output the protective gas in the protective pipeline to the outer periphery of the film tank.

[0011] As a further improvement of the present invention, there are multiple protective pipelines, and each protective pipeline is respectively arranged in different areas on the outer periphery of the film tank;

[0012] Both ends of each protective pipeline are respectively connected to the gas input end and the gas output end, and valves are provided on the connecting pipelines where the protective pipelines are connected to the gas input end and the gas output end respectively.

[0013] As a further improvement of the present invention, the outer periphery of the film tank includes multiple primary monitoring areas, and each primary monitoring area includes multiple protective pipelines;

[0014] Each primary monitoring area includes multiple secondary monitoring areas, and each protective pipeline is arranged in one-to-one correspondence with each secondary monitoring area.

[0015] As a further improvement of the present invention, a branch pipe is connected between two of the protective pipelines located in different primary monitoring areas, and a first differential pressure detection device is provided on the branch pipe, and the distances from both ends of the first differential pressure detection device to the gas output end are the same.

[0016] As a further improvement of the present invention, a branch pipe is connected between two of the protective pipelines located in different secondary monitoring areas, and a second differential pressure detection device is provided on the branch pipe, and the distances from both ends of the second differential pressure detection device to the gas output end are the same.

[0017] As a further improvement of the present invention, the protective pipeline is spirally arranged from the top of the film tank to the bottom of the film tank;

[0018] The protective pipeline includes a plurality of straight sections arranged at intervals in sequence in the vertical direction, each straight section is arranged in the horizontal direction, each bent section is arranged in the vertical direction, and each bent section connects two adjacent straight sections.

[0019] As a further improvement of the present invention, the air outlet holes are distributed on each of the straight sections, and the distances between every two adjacent air outlet holes are arranged in a gradually decreasing form along the pipeline path from the gas input end to the gas output end.

[0020] As a further improvement of the present invention, a third differential pressure detection device is also connected between at least two of the straight sections.

[0021] As a further improvement of the present invention, a temperature detection device is also provided between at least two of the straight sections.

[0022] This application also includes a method for maintaining a thin-film tank, which is maintained by the serpentine maintenance pipeline system for protecting the thin-film tank, and includes the following steps:

[0023] S1. Input a protective gas into the peripheral space of the thin-film tank through the protective pipeline, and evacuate the air in the peripheral space of the thin-film tank to achieve air replacement in the peripheral space of the thin-film tank.

[0024] S2. Continuously input a protective gas into the peripheral space of the thin-film tank through the protective pipeline.

[0025] S3. Continuously input a protective gas into the leakage area, and extract the protective gas and the liquid cargo gas from the protective pipeline adjacent to the leakage area to complete the leakage detection of the leakage area.

[0026] S4. Increase the output amount of the protective gas in the leakage area, and extract the protective gas and the liquid cargo gas from the protective pipeline adjacent to the leakage area to complete the suppression of the liquid cargo leakage in the leakage area.

[0027] As long as the above-mentioned improved technical features do not conflict with each other, they can be combined with each other.

[0028] Generally speaking, compared with the prior art, the beneficial effects of the above technical solutions conceived by the present invention include:

[0029] (1) The serpentine maintenance pipeline system for protecting thin-film tanks in the present invention has a combined structure of straight sections and elbow sections for its protection pipelines. The straight sections are used to form the main body of the pipeline, and the elbow sections are used to connect the straight sections to achieve a spiral distribution around the thin-film tank. At the same time, the protection pipeline has expansion joints. By utilizing the self-expansion and contraction characteristics of the expansion joints, the connection problem of the existing maintenance pipelines during thermal expansion and contraction is solved, ensuring that the protection pipeline is always in an integral structure and will not have problems such as an increase or decrease in the pipeline interval due to thermal expansion and contraction. Moreover, in this application, air vents are opened on the straight sections or elbow sections to output the protection gas transported in the protection pipeline to the external space of the thin-film tank, so as to form a protection gas atmosphere around the thin-film tank. By adjusting the structure of the protection pipeline, this application ensures the stability of the maintenance pipeline system under different temperature conditions such as thermal expansion and contraction, guarantees the stable output of the protection gas and the stability of the discharge of liquid cargo gas, facilitates the staff to master the working conditions of the thin-film tank, and ensures the safety of liquid cargo storage and transportation.

[0030] (2) The serpentine maintenance pipeline system for protecting thin-film tanks in the present invention forms multiple partition protections around the thin-film tank through multiple protection pipeline structures. When the thin-film tank leaks, the fixed-point input of the protection gas can be realized through the protection pipeline in the area where the leak occurs, and the directional output of the protection gas and liquid cargo gas can be realized through the adjacent protection pipelines, so as to achieve the removal of the leaked liquid cargo gas, avoid the leakage of the liquid cargo gas to the entire peripheral area of the thin-film tank, reduce the difficulty of cleaning up the leaked liquid cargo gas, and reduce the maintenance cost of the thin-film tank.

[0031] (3) The method for maintaining a thin-film tank in the present invention forms a protection around the thin-film tank through multiple protection pipelines, realizes the removal of the air around the thin-film tank, the directional injection of the protection gas, the accurate monitoring of the liquid cargo gas, and the accurate removal during liquid cargo leakage. Through the serpentine maintenance pipeline system, the stable output of the protection gas and the stable discharge of the leaked liquid cargo gas are realized. Description of the Drawings

[0032] Figure 1 is the overall structural schematic diagram of the serpentine maintenance pipeline system for protecting thin-film tanks in the embodiment of the present invention;

[0033] Figure 2 is the overall structural schematic diagram of the protection pipeline in the embodiment of the present invention;

[0034] Figure 3 is the flow schematic diagram of the method for maintaining a thin-film tank in the embodiment of the present invention;

[0035] Figure 4 is the gas flow schematic diagram of one of the embodiments of the present invention for inputting the protection gas from the protection pipeline into the peripheral space of the thin-film tank;

[0036] Figure 5It is a schematic diagram of the gas flow direction for inputting protective gas into the peripheral space of the thin-film tank through a protective pipeline in one embodiment of the present invention;

[0037] Figure 6 It is a schematic diagram of the gas flow direction for removing the liquid cargo gas at the leakage area of the thin-film tank in one embodiment of the present invention.

[0038] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0039] 1. Gas input end; 2. Gas output end; 3. Protective pipeline; 4. Second differential pressure detection device; 5. Inlet pressure regulating valve; 6. Inlet pressure and temperature detection device;

[0040] 301. Straight section; 302. Elbow section; 303. Expansion joint; 304. Air outlet hole; 305. Third differential pressure detection device; 306. Temperature detection device. Detailed implementation manners

[0041] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] In the description of the present invention, it should be understood that unless otherwise specified, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", 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 the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0043] In addition, unless otherwise specified, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0044] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0046] Embodiment:

[0047] Please refer to Figures 1 to 6 , Figure 1 which shows a schematic structural view of the serpentine maintenance pipeline system for protecting the thin-film tank of the present application on one side of the thin-film tank. It can be understood that the respective protection pipelines 3 in the circumferential direction of the thin-film tank together form the serpentine maintenance pipeline system for protecting the thin-film tank; Figure 2 which shows a specific structural schematic view of the protection pipeline 3 of the present application; Figure 3 which shows an overall process schematic view of the method for maintaining the thin-film tank of the present application; Figure 4 which shows a schematic view of the gas flow direction in the pipeline when the present application outputs protection gas to one area of the thin-film tank. In the figure, blue represents the schematic view of the flow direction of the input protection gas in the protection pipeline 3, and red represents the protection pipeline 3 discharging the protection gas to the periphery of the thin-film tank through the air outlet 304; Figure 5 which shows a schematic view of the gas flow direction when the present application outputs protection gas to one area of the thin-film tank and sucks the protection gas and air through the side protection pipeline 3. In the figure, blue represents the gas flow direction when the protection gas is input into the protection pipeline 3, and red represents the gas flow direction of discharging the gas to the peripheral space of the thin-film tank and sucking the peripheral space of the thin-film tank into the protection pipeline 3; Figure 6It shows a schematic diagram of the gas flow when the present application inputs a protective gas into this area and sucks the protective gas and the liquid cargo gas through the protective pipelines 3 on both sides when the thin film tank leaks. In the figure, blue represents the gas flow when the protective gas is input into the protective pipeline 3, and red represents the gas flow when the gas is discharged from the peripheral space of the thin film tank and when the peripheral space of the thin film tank is pumped into the protective pipeline 3.

[0048] As Figure 1 shown, the serpentine maintenance pipeline system for protecting the thin film tank in the preferred embodiment of the present invention is arranged on the outer periphery of the thin film tank, and it includes a gas input end 1 and a gas output end 2. Among them, the gas input end 1 is used to introduce a protective gas, and the gas output end 2 is used to output the protective gas and / or the liquid cargo gas to the outside. And a protective pipeline 3, which is arranged around and wrapped on the outer periphery of the thin film tank, and one end of the protective pipeline 3 is connected to the gas input end 1, and the other end thereof is connected to the gas output end 2. Specifically, the protective pipeline 3 includes a straight section 301 and a bent section 302, and the straight section 301 and the bent section 302 are arranged alternately to be spirally arranged on the outer periphery of the thin film tank; at the same time, an expansion joint 303 is correspondingly provided on the straight section 301, and the expansion joint 303 is telescopically arranged; and, air outlet holes 304 are also opened on the straight section 301 and / or the bent section 302, and the protective gas in the protective pipeline 3 can be output to the outer periphery of the thin film tank through the air outlet holes 304 to form a protective gas atmosphere outside the thin film tank.

[0049] Specifically, the serpentine maintenance pipeline system for protecting a thin-film tank in this application adopts a combined structure of a straight section 301 and a bent section 302. The straight section 301 is used to form the main body of the pipeline, and the bent section 302 is used to connect the straight sections 301 to achieve a spiral distribution around the thin-film tank, so as to arrange the pipeline on the outer periphery of the thin-film tank. At the same time, by utilizing the self-expansion and contraction characteristics of the expansion joint 303, the connection problem during thermal expansion and contraction of the existing maintenance pipeline is solved, ensuring that the protection pipeline 3 is always in an integral structure and there will be no problem of increasing or decreasing the pipeline interval due to thermal expansion and contraction. At the same time, in this application, air holes 304 are opened on the straight section 301 and / or the bent section 302 to output the protective gas conveyed in the protection pipeline 3 to the external space of the thin-film tank, so as to form a protective gas atmosphere around the thin-film tank. By adjusting the structure of the protection pipeline 3 in this application, the stability of the maintenance pipeline system under different temperature conditions such as thermal expansion and contraction is ensured, the stable output of the protective gas and the stability of the discharge of the liquid cargo gas are guaranteed, which is convenient for the staff to master the working conditions of the thin-film tank and ensure the safety of liquid cargo storage and transportation. It should be noted that the core of this application is to adjust the maintenance pipeline system into a stable and controllable structure, realizing the quantification of the input and output of the protective gas, and solving the problem that the input and output amounts of the protective gas in the traditional straight pipeline system are uncontrollable during thermal expansion and contraction. By stably monitoring the gas output volume in this application, the effective monitoring of the gas leakage situation of the thin-film tank can be realized, ensuring the safety of liquid cargo storage and transportation.

[0050] Specifically, the serpentine maintenance pipeline system for protecting a thin-film tank in this application is arranged in the shielding layer on the outer periphery of the thin-film tank, and it is provided between the tank body and the thin-film tank.

[0051] It should be noted that thin-film tanks are usually used to store compressed refrigerated liquid cargo, which will quickly vaporize after leakage. Therefore, the liquid cargo leaked to the outside of the thin-film tank is represented by liquid cargo gas in this application.

[0052] Optionally, the thin-film tanks in this application are usually used for the storage and transportation of liquid cargo such as LNG, methanol, ethanol, and ethane. The protective gas input end 1 in this application usually introduces nitrogen and argon as the protective gas. In one embodiment of this application, nitrogen is used as the protective gas.

[0053] Optionally, a negative pressure suction device is provided at the gas output end 2 of this application. Through the negative pressure suction device, active pumping can be achieved to extract the liquid cargo gas leaked from the thin-film tank through the air holes 304 on the protection pipeline 3. Optionally, the gas input end 1 and the gas output end 2 in this application are respectively connected to a protective gas supply source and an exhaust gas treatment device.

[0054] Further, as an optional embodiment of the present invention, there are multiple protective pipelines 3 in the present application, and the multiple protective pipelines 3 are respectively arranged in different areas of the periphery of the membrane tank; the two ends of each protective pipeline 3 are respectively connected to the gas input end 1 and the gas output end 2, and valves are provided on the connecting pipelines between the protective pipeline 3 and the gas input end 1 and the gas output end 2. When a set of protective pipelines 3 is used to protect the periphery of the membrane tank, the protective gas can only reach various places on the outer wall of the membrane tank through a single line, and when the protective gas is discharged to the periphery of the membrane tank through the gas outlet 304, the protective gas cannot be discharged at a fixed point. When the membrane tank leaks, the protective gas protection and the leakage of liquid cargo gas can only be completed by increasing the protective gas input and extraction amount, which will cause a large amount of protective gas waste and be time-consuming and labor-intensive. Based on this, the present application sets up multiple sets of protection pipelines 3 to cover different areas on the periphery of the membrane tank. When there is a liquid cargo leakage, the valve on the protection pipeline 3 in the corresponding area can be adjusted to increase the input and extraction amount of the protection gas in the leakage area at a fixed point, so as to achieve precise protection against liquid cargo leakage, improve the protection efficiency of the membrane tank and reduce the consumption of the protection gas.

[0055] Further, as an optional embodiment of the present invention, the periphery of the membrane tank in the present application includes a plurality of primary monitoring areas, and each primary monitoring area includes a plurality of protective pipelines 3; and each primary monitoring area includes a plurality of secondary monitoring areas, and each protective pipeline 3 is arranged in a one-to-one correspondence with the secondary monitoring area. In order to further improve the efficient fixed-point protection of the external area of ​​the membrane tank by the protective pipeline 3, the present application divides the periphery of the membrane tank into a plurality of primary monitoring areas, and divides the plurality of primary monitoring areas into a plurality of secondary monitoring areas, in this way, a one-to-one correspondence between the protective pipeline 3 and each secondary monitoring area is achieved. Through the refined zoning form, the fixed-point input of the protective gas can be achieved; at the same time, by dividing the primary monitoring area into a plurality of secondary monitoring areas, when a leak occurs in one of the secondary monitoring areas, suction can be performed through the adjacent secondary monitoring area, so as to achieve rapid removal of liquid cargo in the leaking area.

[0056] Further, as an alternative embodiment of the present invention, a branch pipe is connected between one of the protection pipelines 3 located in different primary monitoring areas in this application, and a first differential pressure detection device is provided on the branch pipe, and the distances from both ends of the first differential pressure detection device to the gas output end 2 are the same. When monitoring the leakage condition of the outer periphery of the thin-film tank, under normal working conditions, the protection gas input into each protection pipeline 3 flows at a stable rate, and the first differential pressure detection device between each protection pipeline 3 is in a stable state. By monitoring the differential pressure data of the first differential pressure detection device, the working condition of the thin-film tank can be known. When the thin-film tank leaks, the liquid cargo gas increases in the leakage area, the pressure in the external area corresponding to the protection pipeline 3 increases, resulting in difficulty in discharging the protection gas through the air outlet 304. Eventually, the protection gas output from the protection pipeline 3 to the gas output end 2 increases, and the gas flow rate in the protection pipeline 3 in the leakage area is greater than that in the protection pipeline 3 in the non-leakage area. The first differential pressure detection device correspondingly generates differential pressure data, and based on this, it can be determined whether the thin-film tank leaks and the leakage area.

[0057] Further, as an alternative embodiment of the present invention, a branch pipe is also connected between two protection pipelines 3 located in different secondary monitoring areas in this application, and a second differential pressure detection device 4 is provided on the branch pipe, and the distances from both ends of the second differential pressure detection device 4 to the gas output end 2 are the same. The second differential pressure detection device 4 has a similar function to the first differential pressure detection device. The second differential pressure detection device 4 is mainly used to monitor the differential pressure fluctuation in a smaller area range, so as to more accurately determine the leakage point of the thin-film tank.

[0058] It should be noted that since there are multiple air outlets 304 distributed on the protection pipeline 3 and the gas output pressure of the gas input end 1 is constant, as the protection gas is gradually discharged through the air outlet 304, the gas flow rate in the pipeline closer to the gas input end 1 is faster, and the gas flow rate in the pipeline closer to the gas output end 2 is slower. Therefore, by limiting the positions where the first differential pressure detection device and the second differential pressure detection device 4 are connected to the protection pipeline 3, it is ensured that the gas flow rates at both ends of the differential pressure detection device are nearly the same under the normal maintenance state of the thin-film tank, so as to realize the stable monitoring of the thin-film tank.

[0059] Further, as Figure 2As shown, as an alternative embodiment of the present invention, the protection pipeline 3 in the present application is spirally arranged from the top of the thin-film tank to the bottom of the thin-film tank, wherein the straight sections 301 are arranged vertically at intervals from top to bottom in sequence, and the bent pipe sections 302 connect the straight sections 301. The straight section 301 serves as the main body of the protection pipeline 3. By arranging the straight section 301 in a horizontal layout, when the thin-film tank leaks, each straight section 301 is basically in the same temperature region. The straight section 301 expands and contracts in the horizontal direction, without affecting the overall shape and structure of the protection pipeline 3, ensuring stable monitoring of the leakage situation of the thin-film tank. The bent pipe section 302 serves as the connecting part of the straight section 301 and is arranged in the vertical direction. The bending structure of the bent pipe section 302 itself can eliminate the stress of the protection pipeline 3 in the vertical direction, so as to realize the overall stable connection of the protection pipeline 3. It should be noted that the protection pipeline 3 at the side walls around the thin-film tank in the present application is arranged in this form. The straight sections 301 and the bent pipe sections 302 in the protection pipelines 3 at the top and bottom of the thin-film tank are in the same horizontal plane, and their forms are basically the same as the arrangement form of the protection pipeline 3 at the side walls around the thin-film tank. Moreover, when the thin-film tank in the present application is a cylindrical tank structure, in order to realize that the protection pipeline 3 is wrapped around the outer periphery of the thin-film tank, the straight section 301 and the bent pipe section 302 form an arc-shaped structure to wrap around the outer periphery of the thin-film tank. At this time, the straight section 301 has a certain curvature and forms a quasi-arc-shaped structure.

[0060] Furthermore, as an alternative embodiment of the present invention, the air outlet holes 304 in the present application are distributed on each straight section 301, and the air outlet holes 304 are arranged on the straight section 301 in a non-uniform distance form. The adjacent two air outlet holes 304 are arranged in a form that the distance gradually decreases on the pipeline path from the gas input end 1 to the gas output end 2, so that the amount of protection gas output from each part of the distribution area of the protection pipeline 3 is the same. As mentioned above, the gas flow rate near the gas input end 1 of the protection pipeline 3 is larger, and the gas flow rate near the gas output end 2 is smaller. In order to balance the gas output amount in the area where the protection pipeline 3 is located, the air outlet holes 304 are arranged in a non-uniform distance form, that is, the number of air outlet holes 304 near the gas input end 1 is less, and the number of air outlet holes 304 near the gas output end 2 is more, so as to achieve the balance of the protection gas output amount in the unit area and ensure the uniform distribution of the protection gas around the thin-film tank.

[0061] Further, as an alternative embodiment of the present invention, a third differential pressure detection device 305 is also provided between at least two straight sections 301 in the present application. The third differential pressure detection device 305 is used to identify the differential pressure at different regions inside the protection pipeline 3. In the case where the thin film tank does not leak, the differential pressure between adjacent or alternately arranged straight sections 301 is basically constant. By judging the differential pressure parameter of the third differential pressure detection device 305, it is determined whether there is a leak in the area where the protection pipeline 3 is located. At the same time, when the third differential pressure detection device 305 is arranged between adjacent straight sections 301, the third differential pressure detection device 305 can accurately locate the leak point of the thin film tank. In addition, in order to prevent the leak point from covering the regions where the two straight sections 301 are located, resulting in the second differential pressure detection device 4 being unable to accurately obtain the differential pressure, the third differential pressure detection device 305 can be arranged between multiple alternately arranged straight sections 301 to achieve accurate identification of the leak of the thin film tank. Optionally, the third differential pressure detection device 305 can also be arranged between adjacent straight sections 301 and at the same time between alternately arranged straight sections 301. In the form of cooperation by multiple third differential pressure detection devices 305, the leak point of the thin film tank is comprehensively determined.

[0062] The serpentine maintenance pipeline system for protecting the thin film tank in the present application realizes the zonal and sectional monitoring of the peripheral area of the thin film tank through the cooperative detection of the first differential pressure detection device, the second differential pressure detection device 4, and the third differential pressure detection device 305 at different positions. It can effectively monitor the stability of the air pressure in the initial stage of the leak of the thin film tank, the spreading process, and the subsequent absorption and treatment process, etc., and achieve accurate monitoring during the daily protection, leak detection, and liquid cargo gas removal of the thin film tank.

[0063] Further, as an alternative embodiment of the present invention, a temperature detection device 306 is also provided between at least two straight sections 301 in the present application. In addition to using the pressure detection method to judge whether the thin film tank leaks, it can also be directly judged whether the thin film tank leaks through the temperature detection device 306. When the thin film tank leaks, the pressure in the leak area increases, and the liquid cargo gas leaking from the thin film tank will enter the inside of the protection pipeline 3 through the air outlet 304. The liquid cargo gas is cooler than the protection gas. The temperature detection device 306 can identify whether there is liquid cargo gas entering the protection pipeline 3, so as to judge whether the thin film tank leaks.

[0064] Further, as an alternative embodiment of the present invention, the gas input end 1 in the present application is further connected with an intake pressure regulating valve 5 and an intake pressure and temperature detection device 6. The intake pressure regulating valve 5 is used to increase the gas input volume of the gas input end 1 to meet the high input pressure requirement when the thin-film tank leaks; the intake pressure and temperature detection device 6 is used to detect the temperature and pressure of the protective gas input into the gas input end 1. The protective gas temperature detection is used to compare with the gas temperature detected by the temperature detection device 306 when the thin-film tank leaks to confirm whether the thin-film tank leaks; the protective gas pressure detection is used to determine the input volume of the protective gas, so as to realize the reasonable use of the protective gas while achieving the stable protection of the thin-film tank and avoid excessive waste of the protective gas.

[0065] Further, as an alternative embodiment of the present invention, the present application further includes a method for maintaining a thin-film tank, which is maintained by the above-mentioned serpentine maintenance pipeline system for protecting the thin-film tank. Among them, there are multiple protective pipelines 3, and it includes the following steps:

[0066] S1. Input protective gas into the peripheral space of the thin-film tank through the protective pipeline 3 and evacuate the air in the peripheral space of the thin-film tank to realize the air replacement in the peripheral space of the thin-film tank;

[0067] S2. Continuously input protective gas into the peripheral space of the thin-film tank through the protective pipeline 3;

[0068] S3. Continuously input protective gas into the leakage area, and extract protective gas and liquid cargo gas from the protective pipeline 3 adjacent to the leakage area to complete the leakage detection of the leakage area;

[0069] S4. Increase the output volume of the protective gas in the leakage area, and extract protective gas and liquid cargo gas from the protective pipeline 3 adjacent to the leakage area to complete the suppression of the liquid cargo leakage in the leakage area.

[0070] Specifically, the present application sets a serpentine maintenance pipeline system for protecting the thin-film tank around the thin-film tank, and uses the serpentine pipeline structure to solve the connection stability of the existing pipeline during thermal expansion and contraction, and realizes the stable transportation of the protective gas from the pipeline system to the periphery of the thin-film tank; at the same time, in the method for maintaining the thin-film tank in the present application, through the serpentine maintenance pipeline system for protecting the thin-film tank, a plurality of protective pipelines 3 arranged in a partitioned manner are formed on the periphery of the thin-film tank, realizing the fixed-point and directional input and output of the protective gas, and realizing the directional evacuation and pressure output of the leakage area of the thin-film tank; the directional evacuation of the leakage area of the thin-film tank can prevent the leaked liquid cargo gas from spreading to the entire peripheral area of the thin-film tank, reducing the maintenance cost of the thin-film tank; at the same time, the protective pipeline 3 in the leakage area can separately increase the output of the protective gas in the leakage area to reduce the pressure difference between the inside and outside of the thin-film tank at the leakage point, thereby suppressing the leakage of the liquid cargo and reducing the loss caused by the breakage of the thin-film tank, realizing the precise maintenance of the leakage area of the thin-film tank.

[0071] Further, as an alternative embodiment of the present invention, the air replacement in the peripheral space of the thin-film tank in step S1 of the present application specifically includes:

[0072] S101. The gas input end 1 sequentially inputs protective gas into each protective pipeline 3 to inject protective gas into each area outside the thin-film tank; the gas output end 2 sequentially extracts the protective gas and the air in each area outside the thin-film tank through the protective pipeline 3.

[0073] S102. Sort each protective pipeline 3 in sequence. The gas input end 1 inputs protective gas into one of the protective pipelines 3, and the gas output end 2 extracts the protective gas and the air outside the thin-film tank from the protective pipeline 3 beside this protective pipeline 3.

[0074] S103. The gas input end 1 inputs protective gas through the protective pipeline 3 from which the protective gas was extracted last time, and the gas output end 2 extracts the protective gas and the air outside the thin-film tank from the next protective pipeline 3 beside this protective pipeline 3.

[0075] S104. Repeat step S103 until the input of protective gas is completed for each protective pipeline 3.

[0076] In the present application, first, protective gas is respectively input into each area outside the thin-film tank through each protective pipeline 3 and the air is extracted, so as to realize the preliminary input of protective gas and the preliminary evacuation of air, as Figure 4 shown; secondly, by inputting protective gas through one protective pipeline 3 and extracting the protective gas and air from the adjacent protective pipeline 3, the air in each area outside the thin-film tank is evacuated at fixed points for carpet-like evacuation, ensuring the evacuation of the air outside the thin-film tank and ensuring that the thin-film tank is in an atmosphere of protective gas, as Figure 5 shown.

[0077] Further, as an alternative embodiment of the present invention, in step S2 of the present application, the protective gas is continuously injected into the area outside the thin-film tank mainly through each protective pipeline 3, and at the same time, the gas output end 2 continuously extracts the protective gas in the protective pipeline 3 and the protective gas outside the thin-film tank, so as to realize the dynamic balance of the protective gas in the area outside the thin-film tank and make the thin-film tank in an atmosphere of flowing protective gas.

[0078] Further, as an alternative embodiment of the present invention, in step S3 of the present application, the present application can use the first differential pressure detection device, the second differential pressure detection device 4 and the third differential pressure detection device 305 to judge the leakage area of the thin-film tank; in order to ensure the accuracy of judging the leakage area of the thin-film tank, the present application also needs to continuously input protective gas into the leakage area, and extract the protective gas and the liquid cargo gas through the protective pipeline 3 adjacent to the leakage area, and analyze the gas components at the gas output end 2 to further determine whether there is a leakage problem with the thin-film tank.

[0079] Optionally, this application can also determine whether there is a leakage problem in the thin-film tank through the temperature detection device 306.

[0080] Further, as an optional embodiment of the present invention, after the liquid cargo gas is pumped out and identified in step S3 of this application, it is necessary to pump out the liquid cargo gas that enters the peripheral area of the thin-film tank and suppress the leakage of the liquid cargo. Specifically, in step S4, this application increases the amount of protective gas in the protection pipeline 3 at the leakage area by the gas input end 1 directionally, so that more protective gas is output from the air outlet 304 to increase the amount of protective gas at the leakage area of the thin-film tank, realizing fixed-point pressurization at the leakage area, thereby reducing the internal and external pressure difference of the thin-film tank at the leakage position, and further reducing the leakage amount of the liquid cargo. At the same time, air is pumped through the protection pipeline 3 adjacent to the leakage point to pump away the liquid cargo gas discharged from the leakage area to the periphery, avoiding the pollution of the entire peripheral space of the thin-film tank by the leaked liquid cargo gas and reducing the maintenance cost of the thin-film tank, as Figure 6 shown. It should be noted that when it is necessary to increase the output amount of the protective gas in the protection pipeline 3 of the leakage area of the thin-film tank, the valve between the gas input end 1 and the protection pipeline 3 can be opened, and the valve between the protection pipeline 3 and the gas output end 2 can be closed, so that the protective gas is discharged from the air outlet 304 to increase the amount of protective gas in the peripheral area of the thin-film tank; correspondingly, the valves between the two protection pipelines 3 on the side of the leakage area and the gas input end 1 are closed, and the valves between the two protection pipelines 3 and the gas output end 2 are opened to form a suction area on both sides of the leakage area of the thin-film tank to remove the leaked liquid cargo gas.

[0081] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A serpentine maintenance pipeline system for protecting a thin-film tank, characterized in that, Comprising: A gas input end for introducing a protective gas; A gas output end for outputting the protective gas and / or the liquid cargo gas to the outside; A protective pipeline which is arranged around the outer periphery of the membrane tank; one end of the protective pipeline is connected to the gas input end, and the other end thereof is connected to the gas output end; there are multiple protective pipelines, and each of the protective pipelines is arranged in a different area on the outer periphery of the membrane tank; Both ends of each of the protective pipelines are respectively connected to the gas input end and the gas output end, and valves are provided on the connecting pipelines connecting the gas input end and the gas output end for each of the protective pipelines; The protective pipeline includes a straight section and a bent section, and the straight section and the bent section are alternately connected to be spirally arranged on the outer periphery of the membrane tank; An expansion joint is provided on the straight section, and the expansion joint is telescopically arranged; and, air outlet holes are formed in the straight section and / or the bent section to output the protective gas in the protective pipeline to the outer periphery of the membrane tank.

2. The serpentine maintenance pipeline system for protecting a thin-film tank according to claim 1, wherein, The outer periphery of the membrane tank includes a plurality of primary monitoring areas, and each of the primary monitoring areas includes a plurality of the protective pipelines; Each of the primary monitoring areas includes a plurality of secondary monitoring areas, and each of the protective pipelines is arranged in one-to-one correspondence with each of the secondary monitoring areas.

3. The serpentine maintenance pipeline system for protecting a thin-film tank according to claim 2, wherein, A branch pipe is connected between one of the protective pipelines located in different primary monitoring areas, and a first differential pressure detection device is provided on the branch pipe, and the distances from both ends of the first differential pressure detection device to the gas output end are the same.

4. The serpentine maintenance pipeline system for protecting the thin-film tank according to claim 2, characterized in that, A branch pipe is connected between two of the protective pipelines located in different secondary monitoring areas, and a second differential pressure detection device is provided on the branch pipe, and the distances from both ends of the second differential pressure detection device to the gas output end are the same.

5. The serpentine maintenance pipeline system for protecting a thin-film tank according to claim 1, wherein The protective pipeline is spirally arranged from the top of the membrane tank to the bottom of the membrane tank; The protective pipeline includes a plurality of the straight sections arranged at intervals in sequence in the vertical direction, each of the straight sections is arranged in the horizontal direction, each of the bent sections is arranged in the vertical direction, and each of the bent sections connects two adjacent straight sections.

6. The serpentine maintenance pipeline system for protecting film cans according to claim 5, characterized in that, The air outlet holes are distributed on each of the straight sections, and the distances between each two adjacent air outlet holes are arranged in a gradually decreasing form on the pipeline path from the gas input end to the gas output end.

7. The serpentine maintenance pipeline system for protecting a thin film tank according to claim 5, characterized in that, A third differential pressure detection device is further connected between at least two of the straight sections.

8. The serpentine maintenance pipeline system for protecting a thin-film tank according to claim 5, characterized in that, A temperature detection device is further provided between at least two of the straight sections.

9. A method for maintaining a thin-film tank, which is maintained by the serpentine maintenance pipeline system for protecting the thin-film tank described in any one of claims 1 to 8, characterized in that, Including the following steps: S1. Input a protective gas into the peripheral space of the membrane tank through the protective pipeline, and evacuate the air in the peripheral space of the membrane tank to realize the air replacement of the peripheral space of the membrane tank; S2. Continuously input a protective gas into the peripheral space of the membrane tank through the protective pipeline; S3. Continuously input a protective gas into the leakage area, and extract the protective gas and the liquid cargo gas from the protective pipeline adjacent to the leakage area to complete the leakage detection of the leakage area; S4. Increase the output amount of the protective gas in the leakage area, and extract the protective gas and the liquid cargo gas from the protective pipeline adjacent to the leakage area to complete the suppression of the liquid cargo leakage in the leakage area.

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