Film can insulating layer gas maintenance device and maintenance method

Abstract

The invention discloses a film can insulating layer gas maintenance device and method, and belongs to the technical field of natural gas transportation and storage, the film can insulating layer gas maintenance device comprises a gas input end, a gas output end and a first circulation pipeline, and the gas input end and the gas output end are connected with the first circulation pipeline; a plurality of monitoring sub-pipelines, wherein each monitoring sub-pipeline is connected with the first circulation pipeline; the second circulating pipeline is connected with the monitoring sub-pipelines through branch pipes, valves are arranged between the second circulating pipeline and the monitoring sub-pipelines, and the second circulating pipeline is further connected with a sampling pump. Through the redundancy design mechanism of the first pressure difference detection mechanism and the sampling pump, rapid judgment on the liquid cargo leakage pressure difference is achieved through the first pressure difference detection mechanism, then gas at the possible leakage position is accurately judged through gas analysis of the sampling pump, refined monitoring of the thin film tank is achieved, and the safety of liquid cargo transportation is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural gas transportation and storage, and particularly relates to a gas maintenance device and a maintenance method for the insulation layer of a thin-film tank. Background Art

[0002] As a clean and efficient energy source, liquefied natural gas (LNG) is mainly transported through low-temperature atmospheric or pressure storage tanks. Due to its own low temperature and highly compressed state characteristics, LNG requires high sealing and stability requirements during transportation. Based on the transportation regulations of LNG, 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 layer is filled with dry protective gas to ensure that when the liquid cargo leaks, it is filled in the protective gas atmosphere to avoid the explosion caused by the mixture of liquid cargo and air.

[0003] Existing LNG storage tanks mainly add pressure monitors and gas monitors in the cargo containment system, and judge whether there is leaked liquid cargo invading the cargo containment system by analyzing the gas pressure and components of the cargo containment system. Existing cargo containment systems usually set monitoring devices at a certain point or several points. However, the overall size of the LNG storage tank is large. When the monitoring device detects a leak, the liquid cargo has spread in the maintenance system space for a period of time, resulting in untimely monitoring. In addition, this monitoring method can only know whether the thin-film tank leaks, but the specific leak point of the thin-film tank cannot be known. Summary of the Invention

[0004] In view of one or more of the above-mentioned defects or improvement requirements in the prior art, the present invention provides a gas maintenance device for the insulation layer of a thin-film tank to solve the problem that the existing cargo containment system cannot accurately monitor the leakage area of the thin-film tank.

[0005] To achieve the above object, the present invention provides a gas maintenance device for the insulation layer of a thin-film tank, which includes:

[0006] A gas input end for inputting protective gas;

[0007] A gas output end for outputting protective gas;

[0008] A first circulation pipeline that is arranged around the outer periphery of the thin-film tank in a circular shape. The gas input end and the gas output end are respectively connected to the first circulation pipeline, and the gas input end and the gas output end are symmetrically arranged on both sides of the first circulation pipeline;

[0009] Monitoring sub-pipeline, there are multiple monitoring sub-pipelines, and each monitoring sub-pipeline is distributed around the circumferential direction of the film tank; multiple monitoring sub-pipelines are all connected to the first circulation pipeline, and a valve is provided between each monitoring sub-pipeline and the first circulation pipeline;

[0010] Each monitoring sub-pipeline includes two pipeline openings, the two pipeline openings are arranged towards the outer wall of the film tank, and the two pipeline openings are arranged at intervals, and a first differential pressure detection mechanism is connected in parallel between the two pipeline openings;

[0011] Second circulation pipeline, the second circulation pipeline is connected to each monitoring sub-pipeline through a branch pipe, a valve is provided between the second circulation pipeline and each monitoring sub-pipeline, and a sampling pump is also connected to the second circulation pipeline.

[0012] As a further improvement of the present invention, there are multiple first circulation pipelines, and each first circulation pipeline is vertically stacked in sequence along the side wall of the film tank, and multiple monitoring sub-pipelines are provided on each first circulation pipeline;

[0013] There are multiple second circulation pipelines, and each second circulation pipeline is arranged corresponding to the monitoring sub-pipelines on each first circulation pipeline.

[0014] As a further improvement of the present invention, the sampling pump is also connected to a first incineration unit.

[0015] As a further improvement of the present invention, the first circulation pipeline is also connected to a vacuum pump through a branch pipe, and the vacuum pump is connected to a second incineration unit.

[0016] As a further improvement of the present invention, it further includes a third circulation pipeline, one end of the third circulation pipeline is connected to the vacuum pump, the other end is connected to the gas input end, a pressure swing adsorption module is provided on the third circulation pipeline, and the pressure swing adsorption module is connected to a third incineration unit through a branch pipe.

[0017] As a further improvement of the present invention, the gas input end includes a first input part and a second input part arranged side by side, a second differential pressure detection mechanism is connected in parallel between the first input part and the second input part, both the first input part and the second input part are connected to the first circulation pipeline, and the first input part and the second input part are arranged at intervals on the horizontal plane;

[0018] The gas output end includes a first output part and a second output part arranged side by side, a third differential pressure detection mechanism is connected in parallel between the first output part and the second output part, both the first output part and the second output part are connected to the first circulation pipeline, and the first output part and the second output part are arranged at intervals on the horizontal plane.

[0019] The present application further includes a method for maintaining the gas in the thin-film tank insulation layer, which is maintained by the above-mentioned thin-film tank insulation layer gas maintenance device, and includes the following steps:

[0020] S1. The gas input end inputs protective gas to each monitoring sub-pipeline through the first circulation pipeline, and the gas output end outputs protective gas to each monitoring sub-pipeline through the first circulation pipeline. The protective gas forms a protective gas atmosphere around the thin-film tank through the pipeline openings of each monitoring sub-pipeline;

[0021] S2. The first differential pressure detection mechanism on each monitoring sub-pipeline monitors the air pressure difference between the two pipeline openings. When the air pressure fluctuation at one of the first differential pressure detection mechanisms exceeds the threshold, the second circulation pipeline closes the valves connecting to other monitoring sub-pipelines, and the sampling pump sucks and analyzes the gas in the monitoring sub-pipeline at the air pressure fluctuation point to determine whether there is a leak at the air pressure fluctuation point;

[0022] S3. When a leak occurs, the gas input end inputs protective gas through the monitoring sub-pipeline at the leak point, and the sampling pump sucks the gas in the monitoring sub-pipelines on both sides of the air pressure fluctuation point through the second circulation pipeline;

[0023] When no leak occurs, the second circulation pipeline remains connected to each monitoring sub-pipeline, and the gas input end inputs protective gas to each monitoring sub-pipeline at a uniform speed.

[0024] As a further improvement of the present invention, there are multiple first circulation pipelines, and each of the first circulation pipelines is vertically stacked in sequence along the side wall of the thin-film tank; before the step S1, it further includes protective gas purging:

[0025] Adjust the input differential pressure between the first circulation pipelines, increase the input differential pressure of the gas input end located at the upper end, and reduce the output differential pressure of the gas output end located at the upper end; reduce the input differential pressure of the gas input end located at the lower end, and increase the output differential pressure of the gas output end located at the lower end.

[0026] As a further improvement of the present invention, the gas input end includes two first input parts arranged side by side, and the gas output end includes two first output parts arranged side by side; before the step S1, it further includes protective gas purging: increase the input pressure of the first input part, reduce the input pressure of the second input part, reduce the output pressure of the first output part, and increase the output pressure of the second output part.

[0027] As a further improvement of the present invention, the leak point of the thin-film tank is located on one side of the second input part and the second output part; when a leak occurs in the step S3, it further includes:

[0028] Increase the input pressure of the first input part and reduce the output pressure of the first output part; reduce the input pressure of the second input part and reduce the output pressure of the second output part;

[0029] The sampling pump sucks gas from both sides of the monitoring sub-pipeline at the air pressure fluctuation through the second circulation pipeline.

[0030] As long as the above-mentioned improved technical features do not conflict with each other, they can be combined with each other.

[0031] Generally speaking, compared with the prior art, the beneficial effects of the above technical solutions conceived by the present invention include:

[0032] (1) For the gas maintenance device of the thin-film tank insulation layer of the present invention, through the first circulation pipeline and the monitoring sub-pipeline, the protective gas input from the gas input end is transported to all parts of the periphery of the thin-film tank, so as to form a protective gas atmosphere around the thin-film tank to ensure the safe transportation of the liquid cargo; secondly, when the thin-film tank leaks, the liquid cargo at the leakage position vaporizes and expands, so that the pressure at the leakage position increases, and the pressure difference between the two pipeline openings of the corresponding monitoring sub-pipeline is unbalanced. The first pressure difference detection mechanism can monitor the pressure fluctuation, and then realize the preliminary judgment of the liquid cargo leakage of the thin-film tank; then, through the second circulation pipeline, suction is carried out at the monitoring sub-pipeline at the leakage position to pump the gas at the leakage position into the sampling pump for analysis, so as to further determine whether the corresponding area of the thin-film tank leaks. Through the redundant design mechanism of the first pressure difference detection mechanism and the sampling pump in this application, rapid judgment on the liquid cargo leakage pressure difference and accurate judgment on the gas analysis of the sampling pump are realized, so as to realize the refined monitoring of the thin-film tank and ensure the safety of the liquid cargo transportation.

[0033] (2) For the gas maintenance device of the thin-film tank insulation layer of the present invention, by arranging a plurality of first circulation pipelines vertically along the side wall of the thin-film tank, the monitoring sub-pipelines connected to each first circulation pipeline can monitor the pressure differences in different areas around the thin-film tank, realizing the comprehensive monitoring of the periphery of the thin-film tank; secondly, the arrangement of the first circulation pipelines in different layers enables the input and output of the protective gas in different areas to be separately controllable. By controlling the input and output amounts of the protective gas in different areas around the thin-film tank, the directional flow of the protective gas can be realized, the directional purging of the area around the thin-film tank can be realized, the gas replacement of the insulation layer of the thin-film tank can be completed, and it is convenient to form a protective atmosphere around the thin-film tank subsequently.

[0034] (3) For the gas maintenance device of the thin-film tank insulation layer of the present invention, by setting a third circulation pipeline, the vacuum pump is connected to the gas input end, and a pressure swing adsorption module is arranged between the two. On the one hand, the pressure swing adsorption module can collect the leaked natural gas and separate it from the protective gas, so that the output protective gas can be recycled to the gas input end again to reduce the consumption of the protective gas; on the other hand, it can purify the leaked natural gas so that the natural gas output by the pressure swing adsorption module meets the incineration energy supply standard, so as to use the leaked natural gas for energy supply, avoid the problem of waste caused by the conventional incineration of leaked natural gas, improve the utilization rate of the leaked natural gas, and reduce waste. Brief Description of the Drawings

[0035] Figure 1 is a schematic diagram of the overall structure of the gas maintenance device for the insulation layer of the thin film tank in an embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of the structure of the monitoring sub - pipeline in an embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of the gas flow direction in step S1 in an embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of the gas flow direction in step S3 in an embodiment of the present invention;

[0039] Figure 5 is a schematic diagram of the gas flow direction when a certain protective gas purges the thin film tank in an embodiment of the present invention;

[0040] Figure 6 is a schematic diagram of the gas flow direction when the thin film tank leaks in an embodiment of the present invention;

[0041] Figure 7 is a schematic diagram of the gas flow direction when the thin film tank leaks in an embodiment of the present invention.

[0042] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0043] 101, gas input end; 102, gas output end; 103, first circulation pipeline; 104, monitoring sub - pipeline; 105, second circulation pipeline; 106, sampling pump; 107, first incineration unit; 108, vacuum pump; 109, second incineration unit; 110, third circulation pipeline; 111, pressure swing adsorption module; 112, third incineration unit; 113, first input part; 114, second input part; 115, first output part; 116, second output part; 117, second pressure difference detection mechanism; 118, third pressure difference detection mechanism; 119, thin film tank;

[0044] 1041, pipeline opening; 1042, first pressure difference detection mechanism. Detailed Embodiments

[0045] In order to make the objectives, technical solutions and advantages of the present invention clearer, 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.

[0046] 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. It is 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 should not be construed as a limitation to the present invention.

[0047] 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, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0048] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "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 elements or the interaction relationship between two elements, unless otherwise clearly limited. 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.

[0049] In the present invention, unless otherwise clearly defined and 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.

[0050] Examples:

[0051] Please refer to Figures 1 to 7, in the gas maintenance device for the insulation layer of the thin-film tank 119 in the preferred embodiment of the present invention, it includes a gas input end 101 and a gas output end 102. The gas input end 101 is used for the input of protective gas, and the gas output end 102 is used for the output of protective gas; and a first circulation pipeline 103, which is arranged around the outer periphery of the thin-film tank 119, and the first circulation pipeline 103 is arranged in a ring shape. The gas input end 101 and the gas output end 102 are respectively connected to the first circulation pipeline 103, and the gas input end 101 and the gas output end 102 are symmetrically arranged on both sides of the first circulation pipeline 103; a monitoring sub-pipeline 104, and there are multiple such monitoring sub-pipelines 104, and each monitoring sub-pipeline 104 is distributed around the circumferential direction of the thin-film tank 119; multiple monitoring sub-pipelines 104 are all connected to the first circulation pipeline 103, and a valve is provided between each monitoring sub-pipeline 104 and the first circulation pipeline 103. Each monitoring sub-pipeline 104 includes two pipeline openings 1041, the two pipeline openings 1041 are arranged towards the outer wall of the thin-film tank 119, and the two pipeline openings 1041 are arranged at intervals, and a first differential pressure detection mechanism 1042 is connected in parallel between the two pipeline openings 1041. Further, the second circulation pipeline 105 is connected to each monitoring sub-pipeline 104 through a branch pipe, a valve is provided between the second circulation pipeline 105 and each monitoring sub-pipeline 104, and a sampling pump 106 is also connected to the second circulation pipeline 105. And the first circulation pipeline 103 and the second circulation pipeline 105 do not interfere with each other, and both can complete the gas input or output through the monitoring sub-pipeline 104.

[0052] The gas maintenance device for the insulation layer of the thin-film tank 119 in the present invention transports the protective gas in the gas input end 101 to each monitoring sub-pipeline 104 through the first circulation pipeline 103, and then outputs the protective gas to different areas outside the thin-film tank 119 through the two pipeline openings 1041 of the monitoring sub-pipeline 104 respectively. When the thin-film tank 119 is damaged and leaks, the liquid cargo at the damaged position leaks into the insulation layer area and vaporizes and expands, resulting in an increase in gas pressure at the leakage position, and the pressure at the two pipeline openings 1041 at the leakage position becomes unbalanced. At this time, it can be detected by the first differential pressure detection mechanism 1042, realizing the preliminary monitoring of the leakage of the thin-film tank 119. At the same time, when the thin-film tank 119 leaks, the second circulation pipeline 105 can be used to suck at the monitoring sub-pipeline 104 at the leakage position, and the leaked gas is pumped out to the sampling pump 106 for analysis to further confirm whether the corresponding area of the thin-film tank 119 leaks. Through the redundant design mechanism of the first differential pressure detection mechanism 1042 and the sampling pump 106 in this application, it is avoided that the increase in the flash steam inside the thin-film tank 119 causes the thin-film tank 119 to expand, resulting in a decrease in the distance between the thin-film tank 119 and the pipeline opening 1041, causing the first differential pressure detection mechanism 1042 to misjudge as liquid cargo leakage. This application first uses the first differential pressure detection mechanism 1042 to quickly judge the differential pressure during liquid cargo leakage; then, the sampling pump 106 is used to extract gas at a fixed point for analysis to achieve accurate judgment of liquid cargo leakage, realizing the refined monitoring of the thin-film tank 119 and ensuring the safety of liquid cargo transportation.

[0053] Further, as an alternative embodiment of the present invention, there are multiple first circulation pipelines 103 in the present application, and each first circulation pipeline 103 is arranged vertically and stacked in sequence along the side wall of the thin film tank 119. In the present application, the annular first circulation pipeline 103 can only monitor the leakage of the thin film tank 119 on one horizontal plane, and the leakage of the thin film tank 119 at the upper and lower ends of the first circulation management needs to spread for a period of time before it can be detected by the monitoring sub-pipeline 104. Based on this, the present application provides a structure with multiple first circulation pipelines 103 arranged on the outer periphery of the thin film tank 119, and multiple monitoring sub-pipelines 104 are arranged on each first circulation pipeline 103. By arranging the monitoring sub-pipelines 104 in various circumferential regions of the thin film tank 119, comprehensive monitoring of the circumference of the thin film tank 119 can be achieved. On the other hand, in addition to monitoring various parts of the thin film tank 119, the monitoring sub-pipeline 104 in the present application can also control the gas input and output amounts of the first circulation pipeline 103 at different heights, so as to realize the air pressure difference at different positions of the insulation layer of the thin film tank 119, realize the directional flow of the protective gas, and complete the protective gas purging operation. It should be noted that there are also multiple second circulation pipelines 105, and each second circulation pipeline 105 is arranged in one-to-one correspondence with the monitoring sub-pipelines 104 on each first circulation pipeline 103, so as to realize separate monitoring of the periphery of the thin film tank 119 at different levels. Optionally, multiple second circulation pipelines 105 are all connected to the same sampling pump 106; or each second circulation pipeline 105 is respectively provided with a sampling pump 106.

[0054] Optionally, the protective gas in the present application is nitrogen or argon, preferably nitrogen. It should be noted that other non-combustible gases that do not react with natural gas can also be used as the protective gas.

[0055] Further, as an alternative embodiment of the present invention, the sampling pump 106 is also connected to a first incineration unit 107. When a liquid cargo leak occurs, the gas extracted by the sampling pump 106 contains natural gas. To avoid air pollution and explosion hazards caused by the direct discharge of natural gas, it is necessary to set up a first incineration unit 107 to burn the natural gas in the extracted gas and then discharge it.

[0056] Further, as an alternative embodiment of the present invention, the first circulation pipeline 103 is also connected to a vacuum pump 108 through a branch pipe, and the vacuum pump 108 is connected to a second incineration unit 109. Although the incineration treatment of leaked natural gas can be achieved through the second circulation pipeline 105, the sampling pump 106, and the first incineration unit 107, the sampling analysis requirement of the sampling pump 106 will result in a relatively low extraction efficiency of the sampling pump 106; when a large amount of natural gas leaks, the leaked liquid cargo can be directly extracted through the first circulation pipeline 103 and the vacuum pump 108, and then burned through the second incineration unit 109 to prevent the natural gas at the leakage point from spreading to other areas of the insulation layer of the thin film tank 119, causing a larger range of gas pollution in the insulation layer.

[0057] Further, as an alternative embodiment of the present invention, the thin film tank 119 insulation layer gas maintenance device further includes a third circulation pipeline 110. One end of the third circulation pipeline 110 is connected to the vacuum pump 108, and the other end is connected to the gas input end 101. A pressure swing adsorption module 111 is also provided on the third circulation pipeline 110. The pressure swing adsorption module 111 is connected to a third incineration unit 112 through a branch pipe. Among the leaked gases extracted from the vacuum pump 108, the main component is still the protective gas. The natural gas with a low concentration cannot reach the energy supply standard and can only be burned as waste gas. At the same time, the protective gas will be discharged to the outside, resulting in a large waste of the protective gas. Based on this, the present invention provides the third circulation pipeline 110. The pressure swing adsorption module 111 separates the protective gas from the natural gas, enabling the protective gas to circulate normally to the gas input end 101 and reducing the waste of the protective gas, as Figure 7 shown. On the other hand, the pressure swing adsorption module 111 can enrich the natural gas in the leaked gas. When the natural gas adsorbed by the pressure swing adsorption module 111 reaches the energy supply concentration, the natural gas is transported to the third incineration unit 112 for combustion to supply energy, realizing the effective utilization of the leaked natural gas. Optionally, the pressure swing adsorption module 111 is a device for gas separation, purification, and purification based on pressure swing adsorption technology. It belongs to a conventional gas separation device in the art and will not be elaborated here.

[0058] Furthermore, as an alternative embodiment of the present invention, the gas input end 101 includes a first input part 113 and a second input part 114 arranged side by side. A second differential pressure detection mechanism 117 is connected in parallel between the first input part 113 and the second input part 114. Both the first input part 113 and the second input part 114 are connected to the first circulation pipeline 103, and the first input part 113 and the second input part 114 are arranged at intervals in the horizontal plane. Correspondingly, the gas output end 102 includes a first output part 115 and a second output part 116 arranged side by side. A third differential pressure detection mechanism 118 is connected in parallel between the first output part 115 and the second output part 116. Both the first output part 115 and the second output part 116 are connected to the first circulation pipeline 103, and the first output part 115 and the second output part 116 are arranged at intervals in the horizontal plane. The use of multiple first circulation pipelines 103 can achieve the control of the air flow in the vertical direction of the thin film tank 119, so as to realize the directional purging of the insulation layer area of the thin film tank 119 in the vertical direction; the arrangement form of the gas input end 101 and the gas output end 102 can complete the purging of the gas input end 101 in the horizontal direction of the insulation layer of the thin film tank 119 towards the direction of the gas output end 102, but the purging in the vertical direction between the gas input end 101 and the gas output end 102 cannot be realized. Therefore, the present invention provides the first input part 113 and the second input part 114. By respectively controlling the air flow of the first input part 113 and the second input part 114, the differential pressure on both sides of the first input part 113 and the second input part 114 in the horizontal plane is realized, so that the protective gas flows from one side of the first input part 113 to the other side of the second input part 114, realizing the directional purging of the protective gas in the horizontal plane. Correspondingly, by controlling the suction force of the first output part 115 and the second output part 116, the directional flow of the protective gas can also be completed.

[0059] At the same time, the second differential pressure detection mechanism 117 and the third differential pressure detection mechanism 118 can quantitatively detect the differential pressure between the first input part 113 and the second input part 114, and between the first output part 115 and the second output part 116, so as to adjust the input or output differential pressure and stabilize the purging efficiency and quality of the insulation layer of the thin film tank 119.

[0060] Optionally, booster pumps are correspondingly provided on both the first input part 113 and the second input part 114 to control the gas flow rate of the first input part 113 and the second input part 114; suction pumps are correspondingly provided on both the first output part 115 and the second output part 116 to control the suction pressure of the first output part 115 and the second output part 116.

[0061] Optionally, valves are provided on each pipeline of the gas maintenance device for the insulation layer of the thin film tank 119 in this application.

[0062] Furthermore, the present invention also includes a method for maintaining the gas in the insulation layer of the thin-film tank 119, which is maintained by using the above-mentioned device for maintaining the gas in the insulation layer of the thin-film tank 119, and it includes the following steps:

[0063] S1. The gas input end 101 inputs protective gas to each monitoring sub-pipeline 104 through the first circulation pipeline 103, and the gas output end 102 outputs protective gas to each monitoring sub-pipeline 104 through the first circulation pipeline 103. The protective gas forms a protective gas atmosphere around the thin-film tank 119 through the openings of each monitoring sub-pipeline 104. As Figure 3 shown, the blue lines in the figure represent the flow direction of the protective gas input from the gas input end 101, and the red lines in the figure represent the flow direction of the gas in the insulation layer of the thin-film tank 119 when it is extracted from the gas output end 102. It should be noted that the red and blue lines only represent the flow direction of the gas, and the overall flow of the protective gas in the actual thin-film tank 119 does not have an absolute distinction between inflow and outflow;

[0064] S2. The first differential pressure detection mechanism 1042 on each monitoring sub-pipeline 104 monitors the air pressure difference between the two pipeline openings 1041. When the air pressure fluctuation at one of the first differential pressure detection mechanisms 1042 exceeds the threshold, the second circulation pipeline 105 closes the valves connected to other monitoring sub-pipelines 104, and the sampling pump 106 sucks and analyzes the gas from the monitoring sub-pipeline 104 at the air pressure fluctuation point to determine whether there is a leak at the air pressure fluctuation point;

[0065] S3. When a leak occurs, the gas input end 101 inputs protective gas through the monitoring sub-pipeline 104 at the leak point, and the sampling pump 106 sucks the gas from the monitoring sub-pipelines 104 on both sides of the air pressure fluctuation point through the second circulation pipeline 105. As Figure 4 shown, the blue lines in the figure represent the flow direction of the protective gas input from the gas input end 101, and the red lines in the figure represent the flow direction of the gas in the insulation layer of the thin-film tank 119 when it is extracted from the gas output end 102;

[0066] When no leak occurs, the second circulation pipeline 105 remains connected to each monitoring sub-pipeline 104, and the gas input end 101 inputs protective gas to each monitoring sub-pipeline 104 at a constant speed.

[0067] The method for maintaining the gas in the insulation layer of the thin-film tank 119 in the present invention inputs the protective gas into the insulation layer area of the thin-film tank 119 through the cooperation of the gas input end 101 and the monitoring sub-pipeline 104, and extracts the gas in the insulation layer of the thin-film tank 119 through the cooperation of the gas output end 102 and the monitoring sub-pipeline 104, so as to achieve the dynamic balance of the protective gas in the insulation layer of the thin-film tank 119, making the thin-film tank 119 in an atmosphere of flowing protective gas; when the pressure difference of the first pressure difference detection mechanism 1042 on the monitoring sub-pipeline 104 fluctuates, it means that natural gas leakage may occur in the area where the monitoring sub-pipeline 104 is located. At this time, the valve between the second circulation pipeline 105 and other monitoring sub-pipelines 104 can be closed, and the sampling pump 106 is used to suck at the fixed point of the possible leakage position. By analyzing the gas extracted by the sampling pump 106, it is judged whether a real leakage occurs at the pressure fluctuation point. When the thin-film tank 119 leaks, the protective gas can be input into the monitoring sub-pipeline 104 at the leakage point through the gas input end 101. The way of increasing the pressure of the protective gas can inhibit the leakage of natural gas; at the same time, the sampling pump 106 sucks the gas from the monitoring sub-pipelines 104 on both sides of the pressure fluctuation point through the second circulation pipeline 105. The form of increasing the output of the protective gas at the leakage point and extracting the gas on both sides of the leakage point can prevent the leaked natural gas from spreading to other areas, and suck and discharge the leaked natural gas for treatment, avoiding potential safety hazards caused by the subsequent accumulation of natural gas in the insulation layer.

[0068] Further, as an optional embodiment of the present invention, there are multiple first circulation pipelines 103, and each first circulation pipeline 103 is vertically stacked in sequence along the side wall of the thin-film tank 119. Before step S1, it also includes purging with the protective gas:

[0069] Increase the input pressure of the gas input end 101 at the upper end and decrease the output pressure of the gas output end 102 at the upper end; decrease the input pressure of the gas input end 101 at the lower end and increase the output pressure of the gas output end 102 at the lower end, as Figure 5 shown. The blue lines in the figure represent the flow direction of the protective gas input from the gas input end 101, and the red lines in the figure represent the flow direction of the gas in the insulation layer of the thin-film tank 119 when the gas is extracted from the gas output end 102. By increasing the input amount of the protective gas on the upper side of the thin-film tank 119 and decreasing the output amount of the protective gas on the lower side of the thin-film tank 119, a directional air flow is formed on the upper and lower sides of the thin-film tank 119 to achieve purging of the protective gas from top to bottom, so as to remove the air in the insulation layer of the thin-film tank 119 and make the insulation layer of the thin-film tank 119 in an atmosphere of protective gas.

[0070] Furthermore, as an alternative embodiment of the present invention, the gas input end 101 includes a first input part 113 and a second input part 114 arranged side by side, and the gas output end 102 includes a first output part 115 and a second output part 116 arranged side by side. Before step S1, it further includes a purge with protective gas: increasing the input pressure of the first input part 113, reducing the input pressure of the second input part 114, reducing the output pressure of the first output part 115, and increasing the output pressure of the second output part 116. By increasing the input pressure of the first input part 113 and reducing the input pressure of the first output part 115, the amount of protective gas on the side of the first input part 113 and the first output part 115 increases; by reducing the input pressure of the second input part 114 and increasing the output pressure of the second output part 116, a negative pressure suction is formed on the side of the second input part 114 and the second output part 116 to form a directional flowing air current on both sides, completing the purge with protective gas.

[0071] Furthermore, as an alternative embodiment of the present invention, the air pressure fluctuation is located on the side of the second input part 114 and the second output part 116; when a leak occurs in the thin film tank 119 in step S3, it further includes: increasing the input pressure of the first input part 113 and reducing the output pressure of the first output part 115; reducing the input pressure of the second input part 114 and reducing the output pressure of the second output part 116; the sampling pump 106 sucks gas from both sides of the monitoring sub-pipeline 104 at the air pressure fluctuation through the second circulation pipeline 105, as Figure 6 shown. In the figure, the blue line represents the flow direction of the protective gas input from the gas input end 101, and the red line in the figure represents the flow direction of the gas when the gas in the insulating layer of the thin film tank 119 is extracted from the gas output end 102. When a leak occurs in the thin film tank 119, in order to prevent the natural gas at the leak point from spreading to other areas, the concentration of the protective gas at the location far from the leak point can be increased, so that the protective gas flows towards the leak point, facilitating the sampling pump 106 to pump the natural gas at the leak point away through the second circulation pipeline 105.

[0072] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas maintenance device for a thin-film tank insulation layer, characterized in that, Comprising: A gas input end for inputting protective gas; A gas output end for outputting protective gas; A first circulation pipeline, which is arranged around the outer periphery of the film tank in a circular arrangement. The gas input end and the gas output end are respectively connected to the first circulation pipeline, and the gas input end and the gas output end are symmetrically arranged on both sides of the first circulation pipeline; Monitoring sub-pipelines, there are multiple monitoring sub-pipelines, and each monitoring sub-pipeline is distributed around the circumferential direction of the film tank; multiple monitoring sub-pipelines are all connected to the first circulation pipeline, and a valve is provided between each monitoring sub-pipeline and the first circulation pipeline; Each monitoring sub-pipeline includes two pipeline openings, the two pipeline openings are arranged towards the outer wall of the film tank, and the two pipeline openings are arranged at intervals, and a first differential pressure detection mechanism is connected in parallel between the two pipeline openings; A second circulation pipeline, which is connected to each monitoring sub-pipeline through a branch pipe. A valve is provided between the second circulation pipeline and each monitoring sub-pipeline, and a sampling pump is also connected to the second circulation pipeline.

2. The gas maintenance device for the thin-film tank insulation layer according to claim 1, wherein There are multiple first circulation pipelines, and each first circulation pipeline is vertically stacked in sequence along the side wall of the film tank. A plurality of monitoring sub-pipelines are provided on each first circulation pipeline; There are multiple second circulation pipelines, and each second circulation pipeline is arranged corresponding to the monitoring sub-pipelines on each first circulation pipeline.

3. The gas maintenance device for the thin film tank insulation layer according to claim 1, wherein, The sampling pump is also connected to a first incineration unit.

4. The gas maintenance device for the thin film tank insulation layer according to claim 1, characterized in that The first circulation pipeline is also connected to a vacuum pump through a branch pipe, and the vacuum pump is connected to a second incineration unit.

5. The gas maintenance device for the thin film tank insulation layer according to claim 4, characterized in that, It further includes a third circulation pipeline, one end of the third circulation pipeline is connected to the vacuum pump, and the other end is connected to the gas input end. A pressure swing adsorption module is provided on the third circulation pipeline, and the pressure swing adsorption module is connected to a third incineration unit through a branch pipe.

6. The gas maintenance device for the film tank insulation layer according to claim 1 or 2, characterized in that The gas input end includes a first input part and a second input part arranged side by side. A second differential pressure detection mechanism is connected in parallel between the first input part and the second input part. The first input part and the second input part are both connected to the first circulation pipeline, and the first input part and the second input part are arranged at intervals on the horizontal plane; The gas output end includes a first output part and a second output part arranged side by side. A third differential pressure detection mechanism is connected in parallel between the first output part and the second output part. The first output part and the second output part are both connected to the first circulation pipeline, and the first output part and the second output part are arranged at intervals on the horizontal plane.

7. A method for maintaining the gas in the insulating layer of a thin-film tank, which is maintained by the gas maintenance device for the insulating layer of the thin-film tank as described in any one of claims 1 to 6, characterized in that, Including the following steps: S1. The gas input end inputs protective gas to each monitoring sub-pipeline through the first circulation pipeline, and the gas output end outputs protective gas to each monitoring sub-pipeline through the first circulation pipeline. The protective gas forms a protective gas atmosphere around the film tank through the pipeline openings of each monitoring sub-pipeline; S2. The first differential pressure detection mechanism on each monitoring sub-pipeline monitors the air pressure difference between the openings of the two pipelines. When the air pressure fluctuation at one of the first differential pressure detection mechanisms exceeds the threshold, the second circulation pipeline closes the valve connecting to other monitoring sub-pipelines, and the sampling pump sucks gas through the second circulation pipeline into the monitoring sub-pipeline where the air pressure fluctuation occurs and analyzes it to determine whether there is a leak at the air pressure fluctuation location. S3. When a leak occurs, the gas input end inputs protective gas through the monitoring sub-pipeline at the leak location, and the sampling pump sucks gas through the second circulation pipeline into the monitoring sub-pipelines on both sides of the air pressure fluctuation location. When no leak occurs, the second circulation pipeline remains connected to each monitoring sub-pipeline, and the gas input end uniformly inputs protective gas into each monitoring sub-pipeline.

8. The method for maintaining the gas in the thin-film tank insulation layer according to claim 7, characterized in that, There are multiple first circulation pipelines, and each of the first circulation pipelines is arranged vertically and stacked in sequence along the side wall of the thin film tank; before S1, it also includes purging with protective gas: Increase the input pressure of the gas input end at the upper end and decrease the output pressure of the gas output end at the upper end; decrease the input pressure of the gas input end at the lower end and increase the output pressure of the gas output end at the lower end.

9. The method for maintaining the gas of the thin film tank insulation layer according to claim 7, characterized in that, The gas input end includes two first input parts and two second input parts arranged side by side, and the gas output end includes two first output parts and two second output parts arranged side by side; before S1, it also includes purging with protective gas: increase the input pressure of the first input part, decrease the input pressure of the second input part, decrease the output pressure of the first output part, and increase the output pressure of the second output part.

10. The method for maintaining the gas in the thin film tank insulation layer according to claim 7, characterized in that, The leak location of the thin film tank is on one side of the second input part and the second output part; when a leak occurs in S3, it also includes: Increase the input pressure of the first input part and decrease the output pressure of the first output part; decrease the input pressure of the second input part and decrease the output pressure of the second output part; The sampling pump sucks gas through the second circulation pipeline into the monitoring sub-pipelines on both sides of the air pressure fluctuation location.

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