Inspection method for tank facility

Abstract

A method for inspecting a tank facility provided with: a tank for storing LNG (liquefied natural gas) and piping, connected to the tank, and through which LNG flows, the method comprising the steps of: supplying liquid nitrogen to the tank through the piping; and inspecting the tank device cooled by the liquid nitrogen.

Description

Technical Field

[0001] The invention relates to a method for inspecting tank equipment.

[0002] This application claims priority from Japanese Patent Application No. 2023-038501 filed in Japan on March 13, 2023, the contents of which are incorporated herein by reference. Background Art

[0003] Patent Document 1 discloses a tank facility including a tank capable of carrying LNG (Liquefied Natural Gas) liquid. The LNG liquid is stored in the tank at a low temperature of, for example, -160°C or lower.

[0004] However, in tank facilities such as floating structures and land-based facilities equipped with tanks storing cryogenic LNG, the addition of LNG to the tanks via pipes causes the pipes and tanks to cool. This thermal contraction of the pipes and tanks can lead to defects such as damage to pipe welds, deformation or displacement of pipe bends, deformation of pipe support components, and cracking of the heat-resistant material covering the pipes. Therefore, after installing the tank facility and before actual operation, LNG is actually passed through the pipes to cool them to a temperature equivalent to that in actual operation, and each component is inspected.

[0005] Previous technical literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Publication No. 2020-67139 Summary of the Invention

[0008] Technical issues to be solved by the invention

[0009] To inspect the tank equipment, LNG liquid must be filled into the tank through piping. First, after installing the tank equipment, the air in the piping or tank is replaced with nitrogen or other gas. Next, the piping or tank is filled with LNG gas, which is lower in temperature than nitrogen, and the piping or tank is intermediately cooled to, for example, approximately -20°C. LNG liquid at a temperature below -160°C is then added to the piping, cooling the piping or tank to a temperature equivalent to actual operating conditions, and then various components are inspected.

[0010] However, inspection results indicate that if defects are present, various operations required to address them may be difficult while LNG is present. For example, when repair work is required on pipe welds, welding cannot be performed while flammable LNG is present within the pipes. Consequently, the LNG in the pipes or tanks must be replaced with nitrogen, which is laborious and time-consuming.

[0011] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a tank equipment inspection method that can efficiently perform inspections after the tank equipment is installed and can quickly perform maintenance work when necessary.

[0012] Means for solving technical problems

[0013] To address the above-mentioned issues, the present invention provides a method for inspecting tank equipment comprising a tank and piping. The tank stores LNG. The piping is connected to the tank and allows the LNG to flow through it. The method includes a step of supplying liquid nitrogen and a step of inspecting the tank equipment. In the step of supplying liquid nitrogen, liquid nitrogen is supplied to the tank via the piping. In the step of inspecting the tank equipment, the tank equipment, which is cooled by the liquid nitrogen, is inspected.

[0014] Effects of the Invention

[0015] According to the inspection method of the tank facility of the present invention, it is possible to efficiently perform inspection after the installation of the tank facility, and when maintenance work or the like is necessary, the work can be performed quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a side view of a floating body provided with the tank equipment inspection method according to the embodiment of the present invention.

[0017] Figure 2 It is a diagram showing a schematic configuration of a tank facility according to an embodiment of the present invention.

[0018] Figure 3 This is a flowchart showing the steps of a method for inspecting tank equipment according to an embodiment of the present invention.

[0019] Figure 4 It is a diagram showing a state where nitrogen gas is supplied to the tank facility according to the embodiment of the present invention.

[0020] Figure 5 This is a diagram showing a state where liquid nitrogen is supplied to the tank facility according to the embodiment of the present invention.

[0021] Figure 6 It is a diagram showing a state where LNG gas is supplied to the tank facility according to the embodiment of the present invention.

[0022] Figure 7 This is a diagram showing a state where LNG liquid is supplied to the tank facility according to the embodiment of the present invention. DETAILED DESCRIPTION

[0023] Below, reference Figures 1 to 7The following describes a method for inspecting a tank facility according to an embodiment of the present invention. In this embodiment, a tank facility installed on a floating body floating in water is described as an example.

[0024] (Structure of floating body)

[0025] like Figure 1 As shown, the floating body 1 of this embodiment includes at least a floating body main body 2 and a tank facility 10. Examples of the floating body 1 include a carrier for transporting liquefied gases such as liquefied natural gas (LNG), carbon dioxide, and ammonia, a cargo ship, a ferry, a RORO (Roll-on / Roll-off) ship, a PCTC (Pure Car & Truck Carrier), a passenger ship, and an observation / research ship.

[0026] (Structure of the floating body)

[0027] The floating body 2 has a pair of side panels 3A and 3B, forming its outer shell, a bottom 4, and an upper deck 5. The side panels 3A and 3B have a pair of side plating, forming the port and starboard sides, respectively. The bottom 4 has a bottom plating connecting the side panels 3A and 3B. The pair of side panels 3A and 3B and the bottom 4 form a U-shaped outer shell of the floating body 2 in a cross-section perpendicular to the bow and stern direction Da. The upper deck 5 illustrated in this embodiment is a full-length deck exposed to the outside. On the floating body 2, for example, a superstructure 7 having a living area is formed on the upper deck 5 on the stern 2b side.

[0028] (Structure of tank equipment)

[0029] Figure 2 It is a diagram showing a schematic configuration of a tank facility according to an embodiment of the present invention.

[0030] like Figure 2 As shown, the tank facility 10 includes at least a tank 11 , a pipe 12 , and a safety valve 16 .

[0031] The tank 11 can store LNG. Figure 1 As shown, the tank 11 of this embodiment is housed in the floating body 2. The tank 11 of this embodiment stores LNG as fuel for the combustor 9 such as the main engine, auxiliary engine, and generator engine (none of which are shown) housed in the floating body 2.

[0032] The tank 11 of this embodiment is cylindrical and extends horizontally, and is arranged to extend along the bow-stern direction Da. Furthermore, the tank 11 is not limited to being housed within the main body 2 of the floating structure; for example, it may also be installed on the upper deck 5. Furthermore, there are no restrictions on the number and arrangement of the tanks 11 within the main body 2 of the floating structure. Furthermore, the shape of the tank 11 is not limited to a cylindrical shape; for example, the tank 11 may also be spherical or rectangular.

[0033] Pipe 12 is connected to tank 11. In this embodiment, a loading pipe 13, a discharge pipe 14, and a connecting pipe 15 are provided as pipe 12. Pipe 12 is covered with a heat-insulating material (not shown) outside tank 11. Furthermore, pipe 12 has a double-tube portion outside tank 11, partially covered by an outer pipe (not shown).

[0034] The loading pipe 13 is a pipe used to load LNG supplied from the outside into the tank 11. The loading pipe 13 illustrated in this embodiment penetrates the top of the tank 11 and extends downward from above in the vertical direction Dv inside and outside the tank 11. The front end of the loading pipe 13 (in other words, the lower end in the vertical direction Dv) opens downward at the lower portion of the tank 11.

[0035] The discharge pipe 14 is a pipe used to discharge the LNG within the tank 11 to the outside of the tank 11. The discharge pipe 14 illustrated in this embodiment extends from the outside of the tank 11 through the top of the tank 11 and into the interior of the tank 11. The distal end of the discharge pipe 14 is located in the lower portion of the tank 11. A pump (not shown) is provided at the distal end of the discharge pipe 14. The pump (not shown) is located within the tank 11. The pump (not shown) draws in the LNG within the tank 11 and delivers it to the outside of the tank 11 through the discharge pipe 14.

[0036] The base ends of the loading pipe 13 and the discharge pipe 14 are connected to a fuel storage station 18. External piping such as land-based LNG storage facilities, tank trucks transporting LNG, and coal-loading ships can be detachably connected to the fuel storage station 18. For example, the fuel storage station 18 is installed on at least one of the sides 3A and 3B.

[0037] The safety valve 16 is connected to the tank 11 via the connecting pipe 15. The connecting pipe 15 illustrated in this embodiment is connected to the top of the tank 11 and communicates with the gas flow inside the tank 11. When the pressure inside the tank 11 reaches a preset set pressure, the safety valve 16 releases the pressure inside the tank 11 to the outside.

[0038] (Steps of the inspection method for tank equipment)

[0039] Next, a method for inspecting the tank facility 10 will be described with reference to the drawings.

[0040] Figure 3 This is a flowchart showing the steps of a method for inspecting tank equipment according to an embodiment of the present invention. Figure 4 It is a diagram showing a state in which nitrogen gas is supplied to the tank facility according to the embodiment of the present invention.

[0041] like Figure 3As shown, the inspection method S10 of the tank equipment involved in this embodiment includes a step S11 of supplying nitrogen gas, a step S12 of supplying liquid nitrogen, a step S13 of performing inspection, a step S14 of confirming the inspection result, a step S15 of supplying LNG gas, a step S16 of supplying LNG liquid, and a step S18 of performing maintenance.

[0042] The nitrogen supply step S11 is performed, for example, after the tank facility 10 is installed or modified, and before the tank facility 10 is actually used and LNG is stored in the tank 11. Figure 4 As shown, in the nitrogen supply step S11, nitrogen gas G1 is supplied to the tank 11 via the pipe 12. Nitrogen gas G1 can be supplied to the tank facility 10 from outside the floating body 1 via the fuel storage station 18, for example. Nitrogen gas G1 supplied to the tank facility 10 is supplied to the tank 11 via the loading pipe 13 serving as the pipe 12. If an on-off valve (not shown) is provided on the discharge pipe 14 or the like, it is preferable to open the on-off valve to allow nitrogen gas G1 to flow throughout the tank 11 or the pipe 12 provided in the tank facility 10. Furthermore, to allow nitrogen gas G1 to flow through the discharge pipe 14, a portion of the nitrogen gas G1 flowing from the tank 11 into the discharge pipe 14 can be discharged to the outside of the floating body 1 via the fuel storage station 18.

[0043] In the nitrogen supply step S11, nitrogen gas G1 is fed into the tank 11 via the pipe 12. This replaces the air present in the tank 11 and the pipe 12 that constitute the tank facility 10 after installation with the nitrogen gas G1. In the nitrogen supply step S11, the temperature of the nitrogen gas G1 is adjusted to a predetermined temperature (e.g., -20°C) lower than ambient temperature at the supply source of the nitrogen gas G1. Furthermore, in the nitrogen supply step S11, nitrogen gas G1 at ambient temperature may be initially fed into the tank facility 10, followed by nitrogen gas G1 at a predetermined temperature (e.g., -20°C) lower than ambient temperature. This allows for intermediate cooling of the tank 11 and the pipe 12. The intermediate cooling in the nitrogen supply step S11 need only be completed when the temperature inside the tank 11 drops to a predetermined temperature (e.g., -20°C). The temperature inside the tank 11 can be measured by a temperature sensor (not shown) installed in the tank 11.

[0044] Figure 5 It is a diagram showing a state in which liquid nitrogen is supplied to the tank facility according to the embodiment of the present invention.

[0045] In the step S12 of supplying liquid nitrogen, the tank equipment 10 in which the air is replaced with the nitrogen G1 in the step S11 of supplying nitrogen is Figure 5Liquid nitrogen L1 is supplied as shown. Liquid nitrogen L1 can be supplied to the tank facility 10 from outside the floating body 1 via the fuel storage station 18. The liquid nitrogen L1 supplied to the tank facility 10 is stored in the tank 11 through the loading pipe 13 as the pipe 12. At this time, the nitrogen gas G1 in the loading pipe 13 is pushed by the liquid nitrogen L1 and flows into the tank 11.

[0046] Here, as the storage volume of liquid nitrogen L1 in the tank 11 increases, the pressure of the nitrogen gas G1 in the tank 11 rises. Furthermore, when the pressure of the nitrogen gas G1 in the tank 11 reaches a predetermined set pressure, the safety valve 16 opens. As a result, the nitrogen gas G1 in the tank 11 is released to the outside (e.g., the atmosphere) through the connecting pipe 15.

[0047] In the liquid nitrogen supply step S12, liquid nitrogen L1 is fed into the tank 11 via the pipe 12, thereby replacing the nitrogen gas G1 present in the tank 11 or the pipe 12 with the liquid nitrogen L1. The amount of liquid nitrogen L1 stored can be measured by a liquid level sensor (not shown) that detects the liquid level in the tank 11. In this case, after the liquid nitrogen supply step S12 begins, if the liquid level of liquid nitrogen L1 in the tank 11 detected by the liquid level sensor reaches a predetermined level, the supply of liquid nitrogen L1 can be stopped. Furthermore, to ensure that the liquid nitrogen L1 flows into the discharge pipe 14, a pump (not shown) can be operated to pump the liquid nitrogen L1 stored in the tank 11 into the discharge pipe 14. Furthermore, a portion of the liquid nitrogen L1 pumped into the discharge pipe 14 can be discharged to the exterior of the floating body 1 via the fuel storage station 18.

[0048] When liquid nitrogen L1 is supplied to tank 11 through pipe 12, tank 11 and pipe 12 are cooled by liquid nitrogen L1. Liquid nitrogen L1 is, for example, -180°C or lower, approximately 20°C lower than LNG liquid, which is, for example, -160°C.

[0049] In the inspection step S13, the tank facility 10, cooled by the liquid nitrogen L1 supplied in the liquid nitrogen supply step S12, is inspected. More specifically, in this inspection step S13, personnel visually check for the amount and direction of thermal expansion and contraction of the piping 12 and tank 11, damage to welds of the piping 12 due to thermal expansion and contraction, deformation or displacement of bent portions of the piping 12, deformation of support members of the piping 12, and any defects in the heat shield covering the piping 12 due to thermal expansion and contraction. Liquid nitrogen L1 is, for example, below -180°C, which is lower than the -160°C temperature of LNG liquid. Therefore, the tank facility 10 is inspected under stricter conditions than when the tank 11 is actually in operation, with LNG liquid present within the piping 12 and tank 11. Furthermore, defects in the heat shield can be visually confirmed by checking for so-called cold spots, caused by cooling without heat shielding.

[0050] In step S14 of checking the inspection results, it is determined whether an abnormality has occurred in the tank facility 10 in step S13 of inspecting, the abnormality being caused by thermal expansion (contraction) of the pipe 12 and the tank 11 caused by cooling the cryogenic liquid nitrogen L1 by the tank facility 10 .

[0051] If the result of the inspection result confirmation step S14 indicates that the tank equipment 10 is normal ("YES" in S14), the process proceeds to step S15 for supplying LNG gas. On the other hand, if the result of the inspection result confirmation step S14 indicates that the tank equipment 10 is not normal and some abnormality has occurred ("NO" in S14), the process proceeds to step S18 for performing maintenance.

[0052] In the maintenance step S18, the tank equipment 10 is repaired. Specifically, the parts identified as abnormal in the inspection result confirmation step S14 are repaired. Liquid nitrogen L1 is non-flammable. Therefore, even if the abnormality in the tank equipment 10 is a gas leak, there is no possibility of the leaked gas igniting. Furthermore, maintenance work on the piping 12 or tank 11 using flammable gas, such as welding, can be performed without replacing the liquid nitrogen L1 or nitrogen gas G1 with other inert gases.

[0053] After the tank facility 10 is repaired in step S18, the process returns to step S11 of supplying nitrogen gas. That is, steps S11 to S14 are repeated, and the tank facility 10 is inspected while being cooled with liquid nitrogen L1.

[0054] Figure 6 It is a diagram showing a state in which LNG gas is supplied to the tank facility according to the embodiment of the present invention.

[0055] In the LNG gas supply step S15, LNG gas G2 is supplied to the tank 11 via the pipe 12. The LNG gas G2 is delivered from the outside of the floating body 1 to the tank facility 10 via the fuel storage station 18. The LNG gas G2 delivered to the tank facility 10 is supplied to the tank 11 via the loading pipe 13 as the pipe 12.

[0056] The supplied LNG gas G2 pushes the liquid nitrogen L1 in the pipe 12 and tank 11 out of the tank facility 10 and discharges it. At this time, the temperature of the LNG gas G2 is higher than that of the liquid nitrogen L1. Therefore, the supplied LNG gas G2 vaporizes the liquid nitrogen L1 and discharges it to the outside through the connecting pipe 15.

[0057] Figure 7 It is a diagram showing a state in which LNG liquid is supplied to the tank facility according to the embodiment of the present invention.

[0058] Next, in the LNG liquid supply step S16, LNG liquid L2 is supplied to the tank 11 via the pipe 12. The LNG liquid L2 is delivered from outside the floating body 1 to the tank facility 10 via the fuel storage station 18. The LNG liquid L2 delivered to the tank facility 10 is supplied to the tank 11 via the loading pipe 13 serving as the pipe 12. At this time, the pipe 12, tank 11, and other components of the tank facility 10 are cooled by the liquid nitrogen L1. Therefore, even if the temperature of the pipe 12, tank 11, and other components rises after step S13, the supply of LNG liquid L2 rapidly lowers the temperature. Then, a predetermined amount of LNG liquid L2 is supplied to the tank 11, completing step S16.

[0059] Thereafter, with the LNG liquid L2 stored in the tank facility 10 , the operation of the tank facility 10 is started.

[0060] (Effect)

[0061] In the tank facility inspection method of the above-described embodiment, after liquid nitrogen L1 is supplied to the tank 11 via the pipe 12, the tank facility 10, cooled by the liquid nitrogen L1, is inspected. Liquid nitrogen L1 is, for example, below -180°C, much colder than the LNG liquid L2, which is, for example, -160°C. Therefore, the tank facility 10 can be inspected under more stringent conditions than when the tank 11 is actually in operation, with the LNG liquid L2 present within the pipe 12 and the tank 11. Furthermore, liquid nitrogen L1 is non-flammable. Therefore, the inspection results of the tank facility 10 can prevent the spread of flammable gases around the tank facility 10, even when the liquid nitrogen L1 within the tank facility 10 is drained. Furthermore, the inspection results of the tank facility 10 can prevent ignition of residual gases within the pipe 12 and the tank 11, even when maintenance work involving flames such as welding is required. Consequently, inspections after the installation of the tank facility 10 can be performed efficiently, and maintenance work, etc., can be performed quickly.

[0062] Furthermore, in the above embodiment, based on the results of the inspection of the tank facility 10, if the tank facility 10 is normal, the LNG liquid L2 is supplied to the tank 11 through the pipe 12. This allows the tank facility 10 to be inspected efficiently while the pipe 12 and the tank 11 are thermally contracted by the liquid nitrogen L1, which is lower in temperature than the LNG liquid L2, and then the LNG liquid L2 is supplied to the tank 11 through the pipe 12, effectively transitioning to the operation of the tank facility 10.

[0063] Furthermore, in the above embodiment, if an abnormality is discovered in the tank facility 10 based on the results of the inspection of the tank facility 10, the abnormality can be resolved by repairing the tank facility 10. Furthermore, since liquid nitrogen L1 exists within the piping 12 and the tank 11 during the inspection of the tank facility 10, the release of LNG gas G2, which is a flammable gas, into the surrounding area can be suppressed.

[0064] Furthermore, in the above embodiment, the liquid nitrogen L1 can be vaporized by supplying LNG gas G2 having a higher temperature than the liquid nitrogen L1 in the pipe 12 and the tank 11. This allows the liquid nitrogen L1 in the pipe 12 and the tank 11 to be vaporized and easily discharged outside the tank facility 10.

[0065] Furthermore, in the above embodiment, nitrogen gas G1 is supplied to the tank 11 through the pipe 12 before the step S12 of supplying liquid nitrogen to the tank 11 , thereby cooling the interior of the pipe 12 and the tank 11 to, for example, approximately -20°C.

[0066] Furthermore, in the above-described embodiment, the tank equipment 10 is installed on the floating body 1. In the floating body 1, the movement (swaying) of the floating body 1 causes deformation in the floating body main body 2, resulting in loads being applied to various components of the tank equipment 10. With the tank equipment 10 installed on the floating body 1, inspections of the tank equipment 10 after installation can be performed efficiently, and if maintenance work is required, the work can be performed quickly.

[0067] (Other Implementation Methods)

[0068] While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments and includes design changes that do not depart from the spirit of the present invention.

[0069] Furthermore, in the above embodiment, the tank 11 is exemplified as a tank storing LNG as fuel supplied to the main engine, auxiliary engines, and generator engines (none of which are shown), but the present invention is not limited thereto. The tank facility inspection method of this embodiment may also be applied to tank facilities equipped with tanks storing LNG as cargo.

[0070] Furthermore, the tank equipment 10 is not limited to the floating body 2 of the floating body 1, and may be provided in a floating body of an offshore floating facility, an LNG storage facility on land, or the like.

[0071] Furthermore, the steps of the tank equipment inspection method S10 shown in the above embodiment can be modified as appropriate.

[0072] <Note>

[0073] The inspection method S10 of the tank facility 10 described in the embodiment can be understood as follows, for example.

[0074] (1) In a first embodiment, a method S10 for inspecting a tank facility 10 includes a tank 11 storing LNG (liquefied natural gas) and a pipe 12 connected to the tank 11 and through which the LNG flows. The method S10 includes a step S12 of supplying liquid nitrogen to the tank 11 through the pipe 12 and a step S13 of inspecting the tank facility 10 while it is cooled by the liquid nitrogen L1.

[0075] In the inspection method S10 of the tank facility 10 , liquid nitrogen L1 is supplied to the tank 11 through the pipe 12 , and then the tank facility 10 cooled by the liquid nitrogen L1 is inspected.

[0076] The liquid nitrogen L1 is, for example, -180°C or lower, which is lower than the LNG liquid L2, for example, -160°C.

[0077] Therefore, when the tank 11 is actually used, the tank facility 10 can be inspected under stricter conditions than when the LNG liquid L2 exists in the pipe 12 and the tank 11 .

[0078] Furthermore, liquid nitrogen L1 is non-flammable.

[0079] Therefore, even when the liquid nitrogen L1 in the tank facility 10 is discharged based on the inspection result of the tank facility 10 , for example, it is possible to suppress the flammable gas from diffusing around the tank facility 10 .

[0080] Furthermore, even when maintenance work using hot gases such as welding is required based on the inspection results of the tank facility 10 , ignition of the pipes 12 of the tank facility 10 and residual gas in the tanks 11 can be suppressed.

[0081] Therefore, inspection after installation of the tank facility 10 can be performed efficiently, and when maintenance work or the like is necessary, the work can be performed quickly.

[0082] (2) The inspection method S10 of the tank equipment 10 according to the second embodiment includes, in the inspection method S10 of the tank equipment 10 according to (1), a step S16 of supplying the LNG liquid L2 to the tank 11 through the piping 12 in a case where the tank equipment 10 is normal based on the inspection result of the tank equipment 10.

[0083] Thus, based on the inspection result of the tank facility 10 , when the tank facility 10 is normal, the LNG liquid L2 is supplied to the tank 11 through the pipe 12 .

[0084] Thus, after the tank equipment 10 is inspected effectively while the pipes 12 and tanks 11 are thermally contracted by liquid nitrogen L1, which is lower in temperature than the LNG liquid L2, the LNG liquid L2 is supplied to the tanks 11 through the pipes 12, and the operation of the tank equipment 10 can be effectively transferred to the operation.

[0085] (3) The inspection method S10 of the tank equipment 10 according to the third embodiment is the method S10 of the tank equipment 10 according to (2), and further includes the following step S18 in the step S13 of performing the inspection: if an abnormality is found in the tank equipment 10 based on the result of the inspection of the tank equipment 10, repairing the tank equipment 10.

[0086] Thus, when an abnormality is found in the tank facility 10 based on the results of the inspection of the tank facility 10 , the abnormality in the tank facility 10 can be resolved by performing maintenance on the tank facility 10 .

[0087] Furthermore, when the tank facility 10 is inspected, since the liquid nitrogen L1 exists in the pipe 12 and the tank 11 , it is possible to suppress the release of the LNG gas G2 , which is a flammable gas, into the surroundings.

[0088] (4) The inspection method S10 of the tank facility 10 according to the fourth embodiment is the inspection method S10 of the tank facility 10 according to (2) or (3), further comprising a step S15 of supplying the LNG gas G2 to the tank 11 through the pipe 12 before the step S16 of supplying the LNG liquid L2 to the tank 11.

[0089] Thus, by supplying the LNG gas G2 having a higher temperature than the liquid nitrogen L1 present in the pipe 12 and the tank 11 , the liquid nitrogen L1 can be vaporized.

[0090] This allows the liquid nitrogen L1 in the pipe 12 and the tank 11 to be gasified and easily discharged to the outside of the tank facility 10 .

[0091] (5) The inspection method S10 of the tank facility 10 according to the fifth embodiment is the inspection method S10 of any one of (1) to (4), further comprising a step S11 of supplying nitrogen gas to the tank 11 through the pipe 12 before the step S12 of supplying liquid nitrogen to the tank 11 .

[0092] Thus, before the step S12 of supplying liquid nitrogen to the tank 11 , the nitrogen gas G1 is supplied to the tank 11 through the pipe 12 , whereby the interior of the pipe 12 and the tank 11 can be cooled to, for example, approximately −20° C.

[0093] (6) A sixth aspect of the inspection method S10 for the tank facility 10 is the inspection method S10 for the tank facility 10 according to any one of (1) to (5), wherein the tank facility 10 is installed on a floating structure.

[0094] Examples of the floating body include a floating body of a ship and a floating body of an offshore floating equipment.

[0095] Thus, in the tank facility installed on the floating structure, inspection after the tank facility 10 is installed can be efficiently performed, and when maintenance work or the like is necessary, the work can be performed quickly.

[0096] Industrial applicability

[0097] According to the inspection method of the tank facility of the present invention, it is possible to efficiently perform inspection after the installation of the tank facility, and when maintenance work or the like is necessary, the work can be performed quickly.

[0098] Explanation of symbols

[0099] 1-Floating body, 2-Floating body body, 2b-Stern, 3A, 3B-Side, 5-Upper deck, 7-Superstructure, 9-Burner, 10-Tank equipment, 11-Tank, 12-Piping, 13-Loading piping (piping), 14-Discharge piping (piping), 15-Connecting piping (piping), 16-Safety valve, 18-Fuel storage station, G1-Nitrogen gas, G2-LNG gas, L1-Liquid nitrogen, L2-LNG liquid, S10-Inspection method of tank equipment, S11-Nitrogen gas supply process, S12-Liquid nitrogen supply process, S13-Inspection process, S14-Inspection result confirmation process, S15-LNG gas supply process, S16-LNG liquid supply process, S18-Maintenance implementation process.

Claims

1. A method for inspecting a tank device, the tank device comprising: Tanks for storing LNG (liquefied natural gas); and a pipe connected to the tank and allowing the LNG to flow through; The inspection method of the tank equipment includes the following steps: supplying liquid nitrogen to the tank through the pipe; and An inspection of the tank equipment cooled by the liquid nitrogen is performed.

2. The method for inspecting tank equipment according to claim 1, wherein: The step of performing the inspection further includes the step of supplying LNG liquid to the tank through the pipe when the tank equipment is normal based on the inspection result of the tank equipment.

3. The method for inspecting tank equipment according to claim 2, wherein: The step of performing the inspection further includes a step of repairing the tank equipment if an abnormality is found in the tank equipment based on a result of the inspection of the tank equipment.

4. The method for inspecting tank equipment according to claim 2 or 3, wherein: The method further includes the step of supplying LNG gas to the tank through the pipe before supplying the LNG liquid to the tank.

5. The method for inspecting tank equipment according to claim 1 or 2, wherein: The method further includes the step of supplying nitrogen gas to the tank through the pipe before supplying liquid nitrogen to the tank.

6. The method for inspecting tank equipment according to claim 1 or 2, wherein: The tank equipment is arranged on a floating body.

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