Leak and outgassing inspection system and method

Abstract

A leak and outgassing inspection system according to an embodiment of the present invention comprises: a vacuum transmitter configured to measure the pressure of an insulation space of a double wall of a liquefied gas storage tank; a vacuum pump mounted on a vacuum pipe connected to the insulation space of the double wall of the liquefied gas storage tank, and configured to operate when the pressure of the insulation space measured by the vacuum transmitter rises above a set pressure; and a determination unit analyzing a component of gas sampled during operation of the vacuum pump, and determining whether a cause of an increase in the pressure of the insulation space is any one of a leak or outgassing of the double wall on the basis of an analysis result.

Description

Leak and Outgassing Inspection System and Inspection Method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0149685 filed on October 29, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to a leak and outgassing inspection system and an inspection method thereof, and more specifically, to a leak and outgassing inspection system and an inspection method thereof capable of determining leaks and outgassing by analyzing gas components sampled when pressure is generated in the double wall of a liquefied gas storage tank.

[0005] As is well known, a liquefied gas storage tank includes a double wall that defines a storage space for storing liquefied gases with low temperatures, such as liquid hydrogen (-253°C), and the double wall is composed of a high-performance vacuum insulation structure to stably maintain the temperature of the liquefied gas and prevent loss.

[0006] Liquefied gas storage tanks can minimize Boil-Off Gas (BOG) naturally generated during use or maintain a low Boil-Off Rate (BOR) through a vacuum insulation structure. The vacuum insulation structure of a liquefied gas storage tank can be manufactured by filling a double-wall jacketed insulation space with powdered insulating materials, such as glass bubbles or perlite, and maintaining it at a vacuum pressure. Powdered insulating materials exhibit high insulation performance by blocking heat transfer caused by radiation and convection.

[0007] If outgassing occurs, where moisture or gaseous components are released to the outside from the insulation space of a double-walled liquefied gas storage tank, or if a leak occurs from the outer wall, the pressure in the insulation space increases, which may degrade the insulation performance of the liquefied gas storage tank.

[0008] However, existing leak detection methods had the disadvantage of being unable to accurately distinguish whether the cause of the pressure rise in the insulated space was outgassing or a leak in the outer wall. Consequently, the inability to accurately identify or determine the cause of the pressure rise in the insulated space prevented proper follow-up treatment of the double walls of liquefied gas storage tanks and resulted in the inability to reliably ensure the quality of the double walls.

[0009] The matters described in this background technology section are written to enhance understanding of the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs.

[0010] The present invention has been devised in consideration of the above points, and aims to provide a leak and outgassing inspection system and an inspection method therewith that can accurately determine whether the cause of a pressure rise is a leak or outgassing of the outer wall by analyzing gas components sampled when the pressure rises in the double wall of a liquefied gas storage tank.

[0011] The problems intended to be solved in the embodiments are not limited thereto, and may also include objectives or effects that can be identified from the means of solving the problems or the forms of implementation described below.

[0012] A leak and outgassing inspection system according to an embodiment of the present invention for achieving the above-mentioned purpose may include: a vacuum transmitter configured to measure the pressure of the insulation space of the double wall of a liquefied gas storage tank; a vacuum pump mounted on a vacuum pipe connected to the insulation space of the double wall of the liquefied gas storage tank and configured to operate when the pressure of the insulation space measured by the vacuum transmitter rises above a set pressure; and a judgment unit that analyzes the components of a sampled gas when the vacuum pump operates and determines whether the cause of the pressure rise in the insulation space is either a leak of the double wall or outgassing based on the analyzed result.

[0013] A sampling unit for sampling gas may be positioned at least one of the upstream and downstream sides of the vacuum pump.

[0014] The above judgment unit may be configured to detect whether a judgment gas exists in the sampled gas. The judgment gas may be a gas with a relatively low freezing point.

[0015] When a judgment gas is present in the sampled gas, the judgment unit may be configured to determine that the cause of the pressure rise in the insulation space is a leak in the outer wall of the double wall.

[0016] When no judgment gas is present in the sampled gas, the judgment unit may be configured to determine that the cause of the pressure rise in the adiabatic space is outgassing.

[0017] A leak and outgassing inspection method according to an embodiment of the present invention measures the pressure in the insulation space of the double wall of a liquefied gas storage tank while the liquefied gas is stored in the storage space of a liquefied gas storage tank, and when the pressure in the insulation space rises above a set pressure, samples the gas in the insulation space by operating a vacuum pump, analyzes the sampled gas, and determines whether the cause of the pressure rise in the insulation space is either a leak in the double wall or outgassing based on the analyzed result.

[0018] Gas can be sampled at at least one of the upstream and downstream of the above vacuum pump.

[0019] It detects whether a judgment gas exists in the sampled gas, and the judgment gas may be a gas with a relatively low freezing point.

[0020] When a gas is present in the sampled gas, it can be determined that the cause of the pressure rise in the insulation space is a leak in the outer wall of the double wall.

[0021] When no judgment gas is present in the sampled gas, it can be determined that the cause of the pressure rise in the adiabatic space is outgassing.

[0022] According to the present invention, by analyzing gas components sampled when pressure rises in the double wall of a liquefied gas storage tank, it is possible to accurately determine whether the cause of the pressure rise is a leak or outgassing of the outer wall of the double wall. In this way, by accurately distinguishing or determining the cause of the pressure rise in the insulation space, appropriate subsequent treatment of the double wall of the liquefied gas storage tank can be smoothly carried out, and the quality of the double wall of the liquefied gas storage tank can be stably ensured.

[0023] FIG. 1 is a drawing illustrating a leak and outgassing inspection system according to an embodiment of the present invention.

[0024] FIG. 2 is a flowchart illustrating a leak and outgassing inspection method according to an embodiment of the present invention.

[0025] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0026] In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are used merely to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms used.

[0027] In an embodiment of the present invention, the singular form may include the plural form unless specifically mentioned in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0028] And, where it is stated that a component is 'connected', 'combined', or 'connected' to another component, this may include not only cases where the component is directly connected, combined, or connected to the other component, but also cases where it is 'connected', 'combined', or 'connected' due to another component located between the component and the other component.

[0029] Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0030] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0031] Referring to FIG. 1, a liquefied gas storage tank (1) may include a plurality of double walls (2) that define a storage space (3) for storing liquefied gas. Each double wall (2) may include an inner wall (2a), an outer wall (2b) surrounding the inner wall (2a), and an insulating space (4) defined between the inner wall (2a) and the outer wall (2b).

[0032] The inner wall (2a) can define a storage space (3), and the storage space (3) can be configured to store liquefied gas such as liquefied ammonia gas, liquefied natural gas (LNG), liquefied petroleum gas (LPG), liquefied hydrogen, etc.

[0033] By separating the outer wall (2b) from the inner wall (2a), the insulation space (4) can be limited between the inner wall (2a) and the outer wall (2b), and powdered insulation materials can be filled into the insulation space (4).

[0034] A plurality of sub-vacuum ports (5) may be provided on the outer wall (2b) of the liquefied gas storage tank (1), and each vacuum port (5) may communicate with the insulation space (4) of the double wall (2). The plurality of sub-vacuum ports (5) may be spaced apart from the outer wall (2b) at regular intervals, and a plurality of sub-vacuum pipes (6) may be individually connected to the plurality of vacuum ports (5). A plurality of vacuum valves (6a) may be individually provided to the plurality of sub-vacuum pipes (6). A plurality of sub-vacuum pipes (6) may be connected in parallel to the main vacuum pipe (7).

[0035] A leak and outgassing inspection system (10) according to an embodiment of the present invention may include a vacuum transmitter (11) for measuring the pressure of the insulation space (4) of the double wall (2), a vacuum pump (12) mounted on the main vacuum pipe (7), a sampling unit (SP1, SP2) for sampling gas when the vacuum pump (12) is operated, and a judgment unit (15) for analyzing and judging the gas sampled by the sampling unit (SP1, SP2).

[0036] A vacuum transmitter (11) may be attached to the outer wall (2b) of the double wall (2) and configured to measure the pressure (P) of the insulation space (4) of the double wall (2). When liquefied gas is stored in the storage space (3) of the liquefied gas storage tank (1), the vacuum transmitter (11) can measure the pressure (P) of the insulation space (4) of the double wall (2).

[0037] The controller (13) can determine whether the pressure (P) of the insulation space (4) of the double wall (2), measured by the vacuum transmitter (11), is higher than the set pressure (P1). The set pressure (P1) may be a pressure corresponding to the set vacuum level of the insulation space (4) of the double wall (2).

[0038] A vacuum pump (12) can be mounted on the main vacuum pipe (7), and as the vacuum pump (12) operates, air can be removed through the main vacuum pipe (7) and a plurality of sub-vacuum pipes (6), thereby vacuuming the insulation space (4) of the double wall (2) to a set vacuum level. When the pressure (P) of the insulation space (4) of the double wall (2), measured by the vacuum transmitter (11), becomes higher than the set pressure (P1), the controller (13) can control the vacuum pump (12) to operate.

[0039] As the vacuum pump (12) operates, gas in the insulation space (4) of the double wall (2) can flow to the vacuum pump (12) through the sub-vacuum pipe (6) and the main vacuum pipe (7), and gas can be sampled upstream or downstream of the vacuum pump (12) by the sampling section (SP1, SP2).

[0040] Sampling units (SP1, SP2) may be configured to sample gas upstream or downstream of the vacuum pump (12). Gas may be sampled upstream of the vacuum pump (12) by positioning the upstream sampling unit (SP1) on the main vacuum pipe (7). Gas may be sampled downstream of the vacuum pump (12) by positioning the downstream sampling unit (SP2) at the vent (12a) of the vacuum pump (12).

[0041] The judgment unit (15) can analyze the components of the gas sampled upstream or downstream of the vacuum pump (12) through the sampling unit (SP1, SP2) and, based on the analyzed results, determine whether the leak or outgassing of the outer wall (2b) is the cause of the pressure increase in the insulation space (4) of the double wall (2). If there is damage or incomplete sealing at the part where the outer wall (2b) and various pipes are connected, a leak may occur, and outgassing may occur in which moisture or gas components are discharged to the outside from the insulation space (4) of the double wall (2).

[0042] Specifically, the judgment unit (15) can detect whether a certain amount of judgment gas exists in the sampled gas.

[0043] The pandan gas may be an inert gas with a relatively low freezing point (or boiling point). Specifically, the pandan gas may be a gas, such as helium (He) or neon (Ne), whose freezing point (or boiling point) is lower than that of nitrogen.

[0044] As liquefied gas is stored in the storage space (3) of the liquefied gas storage tank (1), the inner wall (2a) of the double wall (2) can be lowered to an ultra-low temperature level by the liquefied gas, and the insulation space (4) of the double wall (2) can be affected by the liquefied gas and its temperature can be lowered relatively.

[0045] If a leak occurs in the outer wall (2b) of the double wall (2), external air may flow into the insulation space (4) of the double wall (2), and the composition of the sampled gas may differ from the composition of the air at room temperature due to the liquefied gas stored in the storage space (3). Specifically, if the temperature of the inner wall (2a) is lowered due to the liquefied gas and external air flows into the damaged part of the outer wall (2b), components with a relatively high freezing point (or boiling point), such as nitrogen, oxygen, argon, and carbon dioxide in the air, exist only in the liquid state and not in the gaseous state. Furthermore, components with a relatively low freezing point, such as helium (He) and neon (Ne) in the air, exist only in the gaseous state and not in the liquid state. From this, if a leak occurs in the outer wall (2b), only components with a freezing point (or boiling point) lower than that of nitrogen, such as helium (He) and neon (Ne), may exist as the judgment gas in the sampled gas.

[0046] In addition, when outgassing occurs, outside air does not flow into the insulation space (4) of the double wall (2), so the gas is not present in the sampled gas components.

[0047] If a gas is present in the gas components sampled by the judgment unit (15), it may be determined that a leak has occurred in the outer wall (2b), and the damaged part of the outer wall (2b) needs to be repaired. If no gas is present in the gas components sampled by the judgment unit (15), it may be determined that outgassing has occurred, and the pressure (P) in the insulation space (4) of the double wall (2) may be lower than the set pressure (P1) by operating the vacuum pump (12).

[0048] FIG. 2 is a flowchart illustrating a leak and outgassing inspection method according to an embodiment of the present invention.

[0049]

[0050] * Referring to FIG. 2, when liquefied gas is stored in the storage space (3) of the liquefied gas storage tank (1), the pressure (P) of the insulation space (4) of the double wall (2) is measured by the vacuum transmitter (11) (S1).

[0051] The controller (13) determines whether the pressure (P) of the insulation space (4) of the double wall (2), measured by the vacuum transmitter (11), is higher than the set pressure (P1) (S2).

[0052] When the pressure (P) of the insulation space (4) of the double wall (2), measured by the vacuum transmitter (11) in step S2, is determined by the controller (13) not to be higher than the set pressure (P1), the inspection method of the present invention is terminated.

[0053] When the pressure (P) of the insulation space (4) of the double wall (2) measured by the vacuum transmitter (11) in step S2 is determined by the controller (13) to be higher than the set pressure (P1), the controller (13) operates the vacuum pump (12) (S3).

[0054] As the vacuum pump (12) operates, the gas in the insulation space (4) of the double wall (2) can flow to the vacuum pump (12) through the sub-vacuum pipe (6) and the main vacuum pipe (7), and the sampling unit (SP1, SP2) samples the gas in the insulation space (4) of the double wall (2) upstream or downstream of the vacuum pump (12) (S4).

[0055] The judgment unit (15) analyzes the components of the gas sampled by the sampling unit (SP1, SP2) and, based on the analyzed results, determines whether the cause of the pressure rise is a leak or outgassing of the outer wall (2b) (S5). If there is damage or incomplete sealing in the part where the outer wall (2b) and various pipes are connected, a leak may occur, and outgassing may occur in which moisture or gas components are discharged to the outside from the insulation space (4) of the double wall (2).

[0056] The judgment unit (15) determines whether a certain amount of judgment gas exists in the sampled gas (S6). The judgment gas may be an inert gas with a relatively low freezing point (or boiling point). Specifically, the judgment gas may be a gas with a freezing point (or boiling point) lower than the freezing point (or boiling point) of nitrogen, such as helium (He) or neon (Ne).

[0057] As liquefied gas is stored in the storage space (3) of the liquefied gas storage tank (1), the inner wall (2a) of the double wall (2) can be lowered to an ultra-low temperature level by the liquefied gas, and the insulation space (4) of the double wall (2) can be affected by the liquefied gas and its temperature can be lowered relatively. If a leak occurs in the outer wall (2b) of the double wall (2), external air may flow into the insulation space (4) of the double wall (2), and the composition of the sampled gas may differ from the composition of the air at room temperature due to the liquefied gas stored in the storage space (3). Specifically, if the temperature of the inner wall (2a) is lowered by the liquefied gas and external air flows into the damaged part of the outer wall (2b), components with relatively high freezing points (or boiling points), such as nitrogen, oxygen, argon, and carbon dioxide in the air, exist only in a liquid state and not in a gaseous state. Furthermore, components with relatively low freezing points, such as helium (He) and neon (Ne) in the air, exist only in the gaseous phase and not in the liquid phase. Therefore, in the event of a leak in the outer wall (2b), only components with a freezing point (or boiling point) lower than that of nitrogen, such as helium (He) and neon (Ne), can exist as the judgment gas in the sampled gas. Additionally, in the event of outgassing, since outside air does not flow into the insulation space (4) of the double wall (2), the judgment gas does not exist in the sampled gas components.

[0058] When it is determined that a certain amount of gas is present in the gas sampled by the judgment unit (15) in step S6, it is determined that a leak has occurred in the outer wall (2b) (S7). Accordingly, the outer wall (2b) is repaired in a sealed manner by properly handling the damage or incomplete sealing that occurred in the part where the outer wall (2b) and various pipes are connected (S8).

[0059] When it is determined by the judgment unit (15) in step S6 that a certain amount of gas is not present in the sampled gas, it is determined that outgassing is occurring (S9). Accordingly, the controller (13) operates the vacuum pump (12) (S10). By operating the vacuum pump (12), the pressure (P) in the insulation space (4) of the double wall (2) can be lowered below the set pressure (P1).

[0060] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0061] Accordingly, the embodiments disclosed in this invention are intended to illustrate, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments. The scope of protection of this invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of this invention.

Claims

1. A vacuum transmitter configured to measure the pressure in the insulated space of the double wall of a liquefied gas storage tank; A vacuum pump mounted on a vacuum pipe connected to the insulation space of the double wall of the above-mentioned liquefied gas storage tank, configured to operate when the pressure of the insulation space measured by the vacuum transmitter rises above the set pressure; and A leak and outgassing inspection system comprising: a judgment unit that analyzes the components of a sampled gas during the operation of the above vacuum pump and determines, based on the analyzed results, whether the cause of the pressure rise in the insulation space is a leak or outgassing of the double wall.

2. In Claim 1, A leak and outgassing inspection system in which a sampling unit for sampling gas is positioned at least one upstream and downstream of the vacuum pump.

3. In Claim 1, The above judgment unit is configured to detect whether a judgment gas exists in the sampled gas, and The above-mentioned judgment gas is a leak and outgassing inspection system in which the gas has a relatively low freezing point.

4. In Claim 3, A leak and outgassing inspection system configured such that when a judgment gas is present in the sampled gas, the judgment unit determines that the cause of the pressure rise in the insulation space is a leak in the outer wall of the double wall.

5. In Claim 3, A leak and outgassing inspection system configured such that when no judgment gas is present in the sampled gas, the judgment unit determines that the cause of the pressure rise in the adiabatic space is outgassing.

6. Measure the pressure in the insulation space of the double wall of the liquefied gas storage tank while the liquefied gas is stored in the storage space of the liquefied gas storage tank, and When the pressure in the above-mentioned insulation space rises above the set pressure, the gas in the above-mentioned insulation space is sampled by operating the vacuum pump, and A leak and outgassing inspection method that analyzes a sampled gas and determines, based on the analyzed results, whether the cause of the pressure rise in the insulation space is a double wall leak or outgassing.

7. In Claim 6, A leak and outgassing inspection method for sampling gas at at least one of the upstream and downstream of the above vacuum pump.

8. In Claim 6, Detect whether a judgment gas is present in the sampled gas, and The above-mentioned judgment gas is a leak and outgassing inspection method in which the gas has a relatively low freezing point.

9. In Claim 8, A leak and outgassing inspection method that determines that the cause of the pressure rise in the insulation space is a leak in the outer wall of the double wall when a judgment gas is present in the sampled gas.

10. In Claim 8, A leak and outgassing inspection method that determines that the cause of the pressure rise in the adiabatic space is outgassing when no judgment gas is present in the sampled gas.

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