阅读说明：本技术 Lng船用储罐保温层冷检试验装置及方法 (Cold inspection test device and method for heat insulation layer of LNG (liquefied Natural gas) marine storage tank ) 是由 张�林 孟昌顺 朱月坤 于 2018-06-27 设计创作，主要内容包括：本发明涉及LNG储罐技术领域,具体涉及一种LNG船用储罐保温层冷检试验装置及方法。该LNG船用储罐保温层冷检试验装置,包括：低温介质容器,用于存储低温介质,低温介质的沸点≤-163℃；第一支路,其进口端与低温介质容器连通,其出口端用于与LNG储罐连通；第一支路上设置有气化器和第一调节阀；气化器用于将液相低温介质气化为气相低温介质；第一调节阀与气化器的输出端连通,用于控制流通于第一支路中的气相低温介质的传输；第二支路,其进口端与低温介质容器连通,其出口端用于与LNG储罐连通,以向LNG储罐传输液相低温介质；第二支路上设置有第二调节阀,用于控制流通于第二支路中的液相低温介质的传输。利于技术人员对LNG储罐的保温层进行有效地检测。(The invention relates to the technical field of LNG storage tanks, in particular to a cold inspection test device and method for an insulation layer of a storage tank for an LNG ship. This marine storage tank heat preservation cold check test device of LNG includes: the low-temperature medium container is used for storing a low-temperature medium, and the boiling point of the low-temperature medium is less than or equal to-163 ℃; the inlet end of the first branch is communicated with the low-temperature medium container, and the outlet end of the first branch is communicated with the LNG storage tank; the first branch is provided with a gasifier and a first regulating valve; the gasifier is used for gasifying the liquid-phase low-temperature medium into a gas-phase low-temperature medium; the first regulating valve is communicated with the output end of the gasifier and is used for controlling the transmission of the gas-phase low-temperature medium flowing in the first branch; the inlet end of the second branch is communicated with the cryogenic medium container, and the outlet end of the second branch is communicated with the LNG storage tank so as to transmit liquid-phase cryogenic medium to the LNG storage tank; and a second regulating valve is arranged on the second branch and used for controlling the transmission of the liquid-phase low-temperature medium flowing in the second branch. The heat-insulating layer of the LNG storage tank can be effectively detected by technicians.)

1. The utility model provides a test device is examined to marine storage tank heat preservation of LNG cold, its characterized in that includes:

the low-temperature medium container is used for storing a low-temperature medium, and the boiling point of the low-temperature medium is less than or equal to-163 ℃;

the inlet end of the first branch is communicated with the low-temperature medium container, and the outlet end of the first branch is communicated with the LNG storage tank; the first branch is provided with a gasifier and a first regulating valve; the gasifier is used for gasifying the liquid-phase low-temperature medium into a gas-phase low-temperature medium; the first regulating valve is communicated with the output end of the gasifier and is used for controlling the transmission of the gas-phase low-temperature medium flowing in the first branch;

the inlet end of the second branch is communicated with the low-temperature medium container, and the outlet end of the second branch is communicated with the LNG storage tank so as to transmit liquid-phase low-temperature medium to the LNG storage tank; and the second branch is provided with a second regulating valve for controlling the transmission of the liquid-phase low-temperature medium flowing in the second branch.

2. The LNG marine storage tank insulation layer cold check test device of claim 1, wherein the liquid phase cryogenic medium is liquid nitrogen.

3. The LNG marine storage tank insulation cold check test device of claim 1, wherein a pressurization system is provided on the cryogenic medium container.

4. The LNG marine storage tank insulation layer cold detection test device according to claim 1, wherein a cold detection temperature measuring instrument is arranged on the first branch, and the cold detection temperature measuring instrument is communicated with an input end of the vaporizer; the first branch is also provided with a cold detection pressure measuring instrument which is communicated with the output end of the gasifier; and the first branch is also provided with a cold detection safety valve which is communicated with the output end of the gasifier.

5. The LNG marine storage tank insulation layer cold detection test device of claim 1, wherein a cold detection exhaust pipe communicated with an output end of the gasifier is arranged on the first branch, and a cold detection exhaust valve is arranged on the cold detection exhaust pipe.

6. A cold inspection test method for an insulation layer of a storage tank for an LNG ship is characterized by comprising the following steps:

leading out a low-temperature medium from the low-temperature medium container, gasifying the low-temperature medium, inputting the gasified low-temperature medium into the LNG storage tank, and replacing air in the LNG storage tank; wherein the low temperature medium has a boiling point of not higher than-163 ℃;

inputting a liquid-phase low-temperature medium into the LNG storage tank from the low-temperature medium container, reducing the temperature in the LNG storage tank to a set temperature, and checking the condensate state of a heat insulation layer of the LNG storage tank; the lowest set temperature is not higher than-163 ℃.

7. The LNG marine storage tank insulation layer cold check test method according to claim 6, wherein when the liquid-phase low-temperature medium is input into the LNG storage tank, the LNG storage tank is controlled to be gradually lowered to a plurality of set temperatures, and a condensed water state of the insulation layer when the LNG storage tank reaches each set temperature is checked.

8. The LNG marine storage tank insulation cold check test method according to claim 7, wherein when the set temperature reaches-40 ℃, the cryogenic medium container stops delivering the liquid-phase cryogenic medium to the LNG storage tank, and the condensate state of the storage tank insulation is checked;

if the heat insulation layer of the LNG storage tank does not contain condensed water, the low-temperature medium container continues to convey the liquid-phase low-temperature medium to the LNG storage tank, and when the set temperature reaches-120 ℃, the low-temperature medium container stops conveying the liquid-phase low-temperature medium to the LNG storage tank, and the condensed water state of the heat insulation layer of the LNG storage tank is checked;

if the heat-insulating layer of the LNG storage tank does not contain condensed water, the low-temperature medium container continues to convey the liquid-phase low-temperature medium to the LNG storage tank, and when the set temperature reaches-163 ℃, the low-temperature medium container stops conveying the liquid-phase low-temperature medium to the LNG storage tank, and the condensed water state of the heat-insulating layer of the LNG storage tank is checked.

9. The LNG marine storage tank insulation layer cold check test method according to claim 6, wherein a cooling rate of the LNG storage tank is not more than 10 ℃/h in a process of feeding a liquid-phase cryogenic medium into the LNG storage tank.

10. The LNG marine storage tank insulation cold check test method of claim 6, wherein a pressure difference between the cryogenic medium container and the LNG storage tank is made greater than 3barg before the liquid-phase cryogenic medium is introduced into the LNG storage tank.

11. The cold inspection test method for the insulation layer of the LNG marine storage tank according to claim 6, wherein the input of the gaseous cryogenic medium into the LNG storage tank is stopped when a dew point in the LNG storage tank is less than or equal to-40 ℃.

Technical Field

The invention relates to the technical field of LNG storage tanks, in particular to a cold inspection test device and method for an insulation layer of a storage tank for an LNG ship.

Background

The main component of Liquefied Natural Gas (LNG) is methane. The natural gas is cooled to minus 164 ℃ under normal pressure by a low-temperature refrigeration technology so as to be liquefied. Because the critical temperature of LNG is much lower than ambient temperature, it can only be transported and stored under full refrigeration, i.e., atmospheric boiling point (-164 c). LNG storage tanks are cryogenic storage tanks used to store liquefied natural gas.

Disclosure of Invention

In order to overcome the defects, the invention aims to provide a cold detection test device and method for an insulation layer of a storage tank for an LNG ship.

The purpose of the invention is realized by the following technical scheme:

according to an aspect of the present invention, the present invention provides a cold inspection test apparatus for a thermal insulation layer of a storage tank for an LNG ship, comprising:

the low-temperature medium container is used for storing a low-temperature medium, and the boiling point of the low-temperature medium is less than or equal to-163 ℃;

the inlet end of the first branch is communicated with the low-temperature medium container, and the outlet end of the first branch is communicated with the LNG storage tank; the first branch is provided with a gasifier and a first regulating valve; the gasifier is used for gasifying the liquid-phase low-temperature medium into a gas-phase low-temperature medium; the first regulating valve is communicated with the output end of the gasifier and is used for controlling the transmission of the gas-phase low-temperature medium flowing in the first branch;

the inlet end of the second branch is communicated with the low-temperature medium container, and the outlet end of the second branch is communicated with the LNG storage tank so as to transmit liquid-phase low-temperature medium to the LNG storage tank; and the second branch is provided with a second regulating valve for controlling the transmission of the liquid-phase low-temperature medium flowing in the second branch.

Preferably, the liquid-phase cryogenic medium is liquid nitrogen.

Preferably, a pressurization system is arranged on the low-temperature medium container.

Preferably, a cold-detection temperature measuring instrument is arranged on the first branch path, and is communicated with the input end of the gasifier; the first branch is also provided with a cold detection pressure measuring instrument which is communicated with the output end of the gasifier; and the first branch is also provided with a cold detection safety valve which is communicated with the output end of the gasifier.

Preferably, a cold detection exhaust pipe communicated with the output end of the gasifier is arranged on the first branch, and a cold detection exhaust valve is arranged on the cold detection exhaust pipe.

According to another aspect of the invention, the invention provides a cold inspection test method for an insulation layer of a storage tank for an LNG ship, which comprises the following steps:

leading out a low-temperature medium from the low-temperature medium container, gasifying the low-temperature medium, inputting the gasified low-temperature medium into the LNG storage tank, and replacing air in the LNG storage tank; wherein the low temperature medium has a boiling point of not higher than-163 ℃;

inputting a liquid-phase low-temperature medium into the LNG storage tank from the low-temperature medium container, reducing the temperature in the LNG storage tank to a set temperature, and checking the condensate state of a heat insulation layer of the LNG storage tank; the lowest set temperature is not higher than-163 ℃.

Preferably, when the liquid-phase low-temperature medium is input into the LNG storage tank, the LNG storage tank is controlled to gradually lower to a plurality of set temperatures, and the condensed water state of the heat-insulating layer when the LNG storage tank reaches each set temperature is checked.

Preferably, when the set temperature reaches-40 ℃, the low-temperature medium container stops conveying the liquid-phase low-temperature medium to the LNG storage tank, and the condensed water state of the heat insulation layer of the storage tank is checked;

if the heat insulation layer of the LNG storage tank does not contain condensed water, the low-temperature medium container continues to convey the liquid-phase low-temperature medium to the LNG storage tank, and when the set temperature reaches-120 ℃, the low-temperature medium container stops conveying the liquid-phase low-temperature medium to the LNG storage tank, and the condensed water state of the heat insulation layer of the LNG storage tank is checked;

if the heat-insulating layer of the LNG storage tank does not contain condensed water, the low-temperature medium container continues to convey the liquid-phase low-temperature medium to the LNG storage tank, and when the set temperature reaches-163 ℃, the low-temperature medium container stops conveying the liquid-phase low-temperature medium to the LNG storage tank, and the condensed water state of the heat-insulating layer of the LNG storage tank is checked.

Preferably, the cooling speed of the LNG storage tank is not more than 10 ℃/h in the process of inputting the liquid-phase cryogenic medium into the LNG storage tank.

Preferably, the pressure difference between the cryogenic medium vessel and the LNG storage tank is made to be greater than 3barg before the liquid phase cryogenic medium is introduced into the LNG storage tank.

Preferably, the feeding of the gaseous cryogenic medium into the LNG storage tank is stopped when the dew point in the LNG storage tank is less than or equal to-40 ℃.

According to the technical scheme, the invention has the advantages and positive effects that: according to the test device for the cold detection of the heat insulation layer of the LNG marine storage tank, the low-temperature medium in the low-temperature medium container is sent into the gasifier through the first branch, the low-temperature medium is gasified into low-temperature gas by the gasifier, the low-temperature gas is sent into the LNG storage tank through the first branch, and most of air originally existing in the LNG storage tank is replaced to the external environment by the low-temperature gas; the low-temperature medium in the low-temperature medium container is input into the LNG storage tank through the second branch, and the temperature in the LNG storage tank is reduced to a proper set temperature by utilizing the heat absorption of the low-temperature medium; the boiling point of the low-temperature medium is lower than that of the LNG, so that the set temperature can be lower than that of the LNG; at the moment, if the heat insulation layer of the LNG storage tank flows in a foggy shape or condensed water exists, the heat insulation layer leaks cold, and otherwise, the heat insulation layer of the LNG storage tank is good; technical staff can conveniently and effectively detect the heat-insulating layer of the LNG storage tank in time.

Drawings

For the purpose of easy explanation, the present invention will be described in detail with reference to the following preferred embodiments and the accompanying drawings.

FIG. 1 is a schematic structural diagram of a cold detection test device for an insulation layer of an LNG marine storage tank of the invention;

FIG. 2 is a flow chart of a cold inspection test method for an insulation layer of an LNG marine storage tank.

Description of reference numerals: 1. a cryogenic medium vessel; 11. an outlet valve; 2. a first branch; 22. a first regulating valve; 3. a gasifier; 5. an LNG storage tank; 51. a tank evacuation valve; 52. a tank body; 53. a storage tank exhaust pipe; 54. a tank pressure gauge; 55. a tank temperature measuring instrument; 56. a tank relief valve; 6. a second branch circuit; 61. a second regulating valve; 71. cold checking a temperature measuring instrument; 81. cold testing the pressure measuring instrument; 92. cold checking the exhaust pipe; 93. cold check of the evacuation valve; 94. a safety valve for cold detection.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless otherwise explicitly stated or limited. Either mechanically or electrically. Either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The invention provides a cold detection test device for an insulation layer of a storage tank for an LNG ship, which is used for reducing the temperature of an LNG storage tank 5 to a set temperature so as to perform a detection test on the insulation performance of the insulation layer of the LNG storage tank 5. Referring to fig. 1, the LNG tank 5 includes a tank 52, a tank vent pipe 53 disposed on the tank 52, a tank evacuation valve 51 disposed on the tank vent pipe 53, a tank pressure measuring instrument 54 disposed on the tank 52, a tank temperature measuring instrument 55 disposed on the tank 52, and a tank safety valve 56 disposed on the tank 52.

In this embodiment, marine storage tank heat preservation cold check test device of LNG includes that the low temperature medium container 1, the first branch road 2 and the second branch road 6 that connect in parallel that store low temperature medium (not shown in the figure), and the entrance point of first branch road 2 and second branch road 6 all communicates low temperature medium container 1, and the exit end of first branch road 2 and second branch road 6 all communicates the LNG storage tank 5 of treating the experiment. The cryogenic medium container 1 conveys a gas-phase cryogenic medium to the LNG storage tank 5 through the first branch 2, and the cryogenic medium container 1 conveys a liquid-phase cryogenic medium to the LNG storage tank 5 through the second branch 6.

The low-temperature medium container 1 is provided with a pressurization system (not shown) for adjusting the pressure in the low-temperature medium container 1. The cryogenic medium container 1 is provided with an outlet valve 11. Further, the low-temperature medium container 1 is preferably a tank car; the boiling point of the low-temperature medium is not higher than-163 ℃, the low-temperature medium is preferably liquid nitrogen, the boiling point of the liquid nitrogen is-196.25 ℃, and the low-temperature medium is inert, colorless, odorless, non-corrosive, non-combustible, extremely low in temperature and good in safety and economy. Preferably, the pressurization system is a self-pressurization system, and comprises a pressurization gasifier (not shown), wherein when the pressurization is carried out, part of liquid nitrogen is discharged out of the low-temperature medium container 1, and after the liquid nitrogen is gasified by the pressurization gasifier, the liquid nitrogen returns to the gas phase space of the low-temperature medium container 1, so that the purpose of self-pressurization of the low-temperature medium container 1 is achieved.

The inlet end of the first branch 2 is communicated with the low-temperature medium container 1, the outlet end of the first branch is communicated with an LNG storage tank 5 to be tested, the first branch 2 is provided with a gasifier 3 and a first regulating valve 22, wherein the gasifier 3 is an air-temperature gasifier, and the air-temperature gasifier has the advantages of being good in heat exchange effect, strong in corrosion resistance, long in service life, convenient to operate and maintain and the like. A first regulating valve 22 is in communication with the input of the vaporizer for controlling the delivery of the liquid nitrogen circulating in the first branch 2.

The first branch 2 is also provided with a cold detection temperature measuring instrument 71, a cold detection pressure measuring instrument 81, a cold detection exhaust pipe 92, a cold detection exhaust valve 93 and a cold detection safety valve 94.

Specifically, the cold detection temperature measuring instrument 71 is located between the outlet valve 11 and the vaporizer 3, the cold detection pressure measuring instrument 81 is located between the first regulating valve 22 and the vaporizer 3, and the cold detection safety valve 94 is located between the first regulating valve 22 and the vaporizer 3; cold temperature measuring instrument 71 and cold pressure measuring instrument 81 of examining do benefit to the temperature of the input of technical staff in time knowing vaporizer 3 and the pressure condition of output, cooperate with first cold relief valve 94 of examining, have ensured the marine storage tank heat preservation of LNG cold check test device's security.

A cold check exhaust pipe 92 is provided between the first regulator valve 22 and the vaporizer 3, and a cold check exhaust valve 93 is installed on the cold check exhaust pipe 92. When the air in the LNG storage tank 5 is replaced by the low-temperature nitrogen, the cold inspection exhaust valve 93 on the cold inspection exhaust pipe 92 can be opened, so that the nitrogen can be used for rapidly exhausting the air in the first branch 2.

The inlet end of the second branch 6 is communicated with the low-temperature medium container 1, and the outlet end of the second branch is communicated with an LNG storage tank 5 to be tested; a second regulating valve 61 is mounted on the second branch 6 for controlling the delivery of the liquid nitrogen circulating in the second branch 6.

In this embodiment, the inlet ends of the first branch 2 and the second branch 6 are both connected to the cryogenic medium container 1 via an outlet valve 11. Of course, the inlet ends of the first branch 2 and the second branch 6 can also communicate directly with the cryogenic medium container 1. The first branch 2 and the second branch 6 can adopt low-temperature hoses to transmit low-temperature media.

The method for testing the cold insulation layer of the LNG marine storage tank according to the present invention will be described below. The method can be performed based on the LNG marine storage tank heat-insulating layer cold inspection test device.

Referring to fig. 2, the invention further provides a cold inspection test method for the insulation layer of the LNG marine storage tank, wherein the method can be performed based on the cold inspection test device for the insulation layer of the LNG marine storage tank. For convenience of understanding, referring to fig. 1, the following detailed description is made with reference to a specific structure of the cold testing apparatus for the insulation layer of the LNG ship storage tank, and liquid nitrogen is taken as an example of the low-temperature medium.

A cold inspection test method for an insulation layer of a storage tank for an LNG ship comprises the following steps:

s1, leading out the low-temperature medium from the low-temperature medium container, gasifying the low-temperature medium, inputting the gasified low-temperature medium into the LNG storage tank, and replacing air in the LNG storage tank; wherein the low temperature medium has a boiling point of not higher than-163 ℃;

specifically, the second regulating valve 61 is closed, the outlet valve 11, the first regulating valve 22 and the storage tank evacuation valve 51 on the LNG storage tank 5 are opened, the pressure of the cryogenic medium container 1 is regulated by the pressurization system, so that the liquid nitrogen in the cryogenic medium container 1 is sent into the vaporizer 3 through the first branch 2, the vaporizer 3 vaporizes the liquid nitrogen into nitrogen gas, the nitrogen gas is sent into the LNG storage tank 5 through the second branch 6, the replacement of the nitrogen gas in the LNG storage tank 5 with air is completed, and the air originally existing in the LNG storage tank 5 is discharged to the external environment through the storage tank evacuation valve 51 on the storage tank exhaust pipe 53. When the dew point of the nitrogen discharged from the storage tank exhaust pipe 53 is less than or equal to minus 40 ℃, the outlet valve 11 and the first regulating valve 22 are closed, and the replacement of the air by the nitrogen is stopped. When the dew point is-40 ℃, most of air is replaced by nitrogen, and the moisture is reduced by more than 90% compared with the normal temperature, so that the storage tank is prevented from being damaged by water vapor.

S2, inputting a liquid-phase low-temperature medium into the LNG storage tank from the low-temperature medium container, reducing the temperature in the LNG storage tank to a set temperature, and checking the condensate state of the heat-insulating layer of the LNG storage tank; the lowest set temperature is not higher than-163 ℃.

Specifically, the pressure of the cryogenic medium container 1 is increased through the pressurization system, when the pressure difference between the cryogenic medium container 1 and the LNG storage tank 5 is greater than 3barg and the pressure in the LNG storage tank 5 does not exceed 9barg, the outlet valve 11 and the second regulating valve 61 are opened, the cryogenic medium container 1 conveys liquid nitrogen to the LNG storage tank 5 through the second branch 6, wherein the opening degree of the outlet valve 11 and the second regulating valve 61 can be controlled so that the temperature reduction speed of the storage tank is not greater than 10 ℃/h, preferably 10 ℃/h, and the liquid nitrogen is prevented from intensively entering the tank body 52, so that the temperature of the tank body 52 is reduced unevenly, and the tank body 52 is damaged. Tank pressure gauge 54 facilitates the technician to understand the pressure conditions within tank 52; the tank temperature gauge 55 facilitates the technician to know the temperature inside the tank 52 and thus control the opening of the outlet valve 11 and the second regulating valve 61.

After the temperature of the LNG storage tank 5 reaches-40 ℃, the temperature is stabilized for 10 minutes, the outlet valve 11 or the second regulating valve 61 is closed, and the state of the heat insulation layer of the LNG storage tank 5 is preliminarily checked.

If the mist flow or the condensed water is not found in the heat insulation layer of the LNG storage tank 5, the outlet valve 11 or the second regulating valve 61 is opened again, the liquid nitrogen is continuously input into the LNG storage tank 5, the temperature reduction speed is preferably 10 ℃/h, after the temperature in the tank reaches-120 ℃, the tank is stabilized for 10 minutes, the outlet valve 11 or the second regulating valve 61 is closed, and the state of the heat insulation layer is checked again.

If the thermal insulation layer of the LNG storage tank 5 does not flow in a foggy mode or have condensed water, opening the outlet valve 11 or the second regulating valve 61 again, continuing to spray liquid nitrogen into the LNG storage tank 5 to cool the LNG storage tank 5, wherein the cooling speed is preferably 10 ℃/h until the temperature of the LNG storage tank 5 is-163 ℃, stabilizing for 10 minutes, closing the outlet valve 11 or the second regulating valve 61, checking the state of the thermal insulation layer of the LNG storage tank 5, and judging whether the outer surface of the thermal insulation layer flows in a foggy mode or has condensed water.

In the detection step, if the insulating layer has vaporific flow or condensed water, the insulating layer leaks cold, the mark and the record are made, the LNG storage tank 5 is repaired after being heated to the normal temperature, and the cold detection test is repeatedly carried out. On the contrary, the heat insulating layer of the LNG tank 5 at the set temperature is good.

After the cold detection is finished, the storage tank emptying valve 51 on the LNG storage tank 5 is closed, the first branch 2 is separated from the LNG storage tank 5, and an external protection blind plate and a pressure gauge are installed on the LNG storage tank 5 according to the shipping state. After the nitrogen in the tank absorbs heat, the pressure of the LNG storage tank 5 slowly rises, the storage tank evacuation valve 51 on the LNG storage tank 5 is opened at a proper time to discharge the nitrogen, the gas pressure in the LNG storage tank 5 is maintained at about 0.5barg at normal temperature, and the nitrogen is used as an internal protective gas for shipping the LNG storage tank 5.

The invention has at least the following advantages:

1. according to the cold detection test device for the heat-insulating layer of the storage tank for the LNG ship, disclosed by the invention, the second regulating valve 61 is closed firstly, the outlet valve 11 and the storage tank emptying valve 51 are opened, so that liquid nitrogen in the low-temperature medium container 1 is sent into the vaporizer 3 through the first branch 2, the vaporizer 3 vaporizes the liquid nitrogen into nitrogen, the nitrogen is sent into the LNG storage tank 5 through the first branch 2, the replacement of the air in the LNG storage tank 5 by the nitrogen is completed, and the air originally existing in the LNG storage tank 5 is discharged to the external environment through the storage tank exhaust pipe 53 and the storage tank emptying valve 51; after most of the air in the LNG storage tank 5 is replaced by nitrogen, the first regulating valve 22 is closed, the second regulating valve 61 is opened, the opening degrees of the outlet valve 11 and the second regulating valve 61 are controlled, so as to control the cooling rate of the LNG storage tank 5 within 10 ℃/h, and the liquid nitrogen in the low-temperature medium container 1 is input into the LNG storage tank 5 through the second branch 6, so as to reduce the temperature in the LNG storage tank 5 to the set temperature; the boiling point of the liquid nitrogen is lower than that of the LNG, so that the set temperature can be lower than that of the LNG; at this time, if the heat insulation layer of the LNG storage tank 5 flows in a fog shape or has condensed water, the heat insulation layer leaks cold, otherwise, the heat insulation layer of the LNG storage tank 5 is good; the heat insulation layer of the LNG storage tank 5 can be effectively detected by technicians; the cold check test can be carried out to independent C type LNG storage tank.

2. The safety of the tested storage tank and the tested equipment is ensured through the replacement of nitrogen and the controllable cooling speed, the drying and inerting of the storage tank and the filling of the shipping protective gas can be simultaneously completed, and the corresponding cost and time can be saved.

3. The cold detection temperature measuring instrument 71, the cold detection pressure measuring instrument 81 and the cold detection safety valve 94 ensure the safety of the LNG marine storage tank heat insulation layer cold detection test device. When the air in the LNG storage tank 5 is replaced by nitrogen, the cold inspection exhaust valve 93 on the cold inspection exhaust pipe 92 can be opened, so that the gaseous nitrogen can be used for rapidly exhausting the air in the first branch 2.

In the description of the present specification, reference to the description of the terms "one embodiment", "some embodiments", "an illustrative embodiment", "an example", "a specific example", or "some examples", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.