The invention discloses a bimetallic cryogenic membrane storage compartment for liquefied natural gas (LNG) storage. The invention is based on the design of bimetallic membrane panels and two insulating panels to achieve two completely independent insulation spaces, fully meeting the relevant requirements of the amendments to the International Code for the Construction and Equipment of Ships Carrying Liquefied Natural Gas in Bulk (“IGC CODE”) adopted on May 22, 2014. The invention improves the safety of the cryogenic membrane storage compartment, reduces the limitation of free liquid level loading of liquid cargo in the cargo compartment, reduces the application and time consuming of low-temperature resistant glue in the construction process, and adopts the more mature and safe design method of welding bimetallic membrane panels and the environmental protection method of prefabricated foam insulation panels, thus reducing the construction workload, shortening the construction cycle and improving the safety of the equipment.

An apparatus for reliquefaction of boil-off gas for a vessel, comprises: a compression unit for compressing the boil-off gas discharged from the storage tank; and a heat exchanger for heat-exchanging the compressed boil-off gas compressed by the compression unit with the boil-off gas discharged from the storage tank; a first expansion means for dividing the boil-off gas passing through the heat exchanger into at least two flows including a first flow and a second flow, and expanding the divided first flow; a first intercooler for cooling the second flow remaining after the division of the first flow by using the first flow expanded by the expansion means as a refrigerant; and a receiver for receiving a second flow having passed through the first intercooler, in which a downstream pressure of the compression unit is controlled by a flow discharged from the receiver.

An apparatus for reliquefaction of boil-off gas for a vessel, comprises: a compression unit for compressing the boil-off gas discharged from the storage tank; and a heat exchanger for heat-exchanging the compressed boil-off gas compressed by the compression unit with the boil-off gas discharged from the storage tank; a first expansion means for dividing the boil-off gas passing through the heat exchanger into at least two flows including a first flow and a second flow, and expanding the divided first flow; a first intercooler for cooling the second flow remaining after the division of the first flow by using the first flow expanded by the expansion means as a refrigerant; and a receiver for receiving a second flow having passed through the first intercooler, in which a downstream pressure of the compression unit is controlled by a flow discharged from the receiver.

Disclosed herein are a diagnostic method using laser induced breakdown spectrum analysis and a diagnostic device for performing the same. The diagnostic device may include a laser projection module projecting a pulsed laser to a specimen, a light receiving module receiving a light generated by a plasma ablation induced at the specimen by the pulsed laser, a spectral member receiving and dividing the light generated by the plasma ablation; a sensor array including a plurality of sensors arranged to receive the divided light for each wavelength, and a controller obtaining spectrum data of the light generated by the plasma ablation from a specific exposure period, and determining whether or not the specimen is diseased based on the spectrum data of the light generated by the plasma ablation.

Disclosed herein are a diagnostic method using laser induced breakdown spectrum analysis and a diagnostic device for performing the same. The diagnostic device may include a laser projection module projecting a pulsed laser to a specimen, a light receiving module receiving a light generated by a plasma ablation induced at the specimen by the pulsed laser, a spectral member receiving and dividing the light generated by the plasma ablation; a sensor array including a plurality of sensors arranged to receive the divided light for each wavelength, and a controller obtaining spectrum data of the light generated by the plasma ablation from a specific exposure period, and determining whether or not the specimen is diseased based on the spectrum data of the light generated by the plasma ablation.

Disclosed herein is a BOG reliquefaction method for LNG ships. The BOG reliquefaction method for LNG ships includes: 1) compressing BOG; 2) cooling the BOG compressed in Step 1) through heat exchange between the compressed BOG and a refrigerant using a heat exchanger; 3) expanding the BOG cooled in Step 2); and 4) stably maintaining reliquefaction performance regardless of change in flow rate of the BOG compressed in Step 1) and supplied to the heat exchanger to be used as a reliquefaction target.

Disclosed herein is a BOG reliquefaction method for LNG ships. The BOG reliquefaction method for LNG ships includes: 1) compressing BOG; 2) cooling the BOG compressed in Step 1) through heat exchange between the compressed BOG and a refrigerant using a heat exchanger; 3) expanding the BOG cooled in Step 2); and 4) stably maintaining reliquefaction performance regardless of change in flow rate of the BOG compressed in Step 1) and supplied to the heat exchanger to be used as a reliquefaction target.

A BOG reliquefaction system includes: a compressor; a heat exchanger cooling the BOG compressed by the compressor through heat exchange using BOG not compressed by the compressor; a pressure reducer disposed downstream of the heat exchanger and reducing a pressure of fluid cooled by the heat exchanger; and a combination of a first temperature sensor disposed upstream of a cold fluid channel of the heat exchanger and a fourth temperature sensor disposed downstream of a hot fluid channel of the heat exchanger, combination of a second temperature sensor disposed downstream of the cold fluid channel of the heat exchanger and a third temperature sensor disposed upstream of the hot fluid channel of the heat exchanger, or combination of a first pressure sensor disposed upstream of the hot fluid channel of the heat exchanger and a second pressure sensor disposed downstream of the hot fluid channel of the heat exchanger.

A BOG reliquefaction system includes: a compressor; a heat exchanger cooling the BOG compressed by the compressor through heat exchange using BOG not compressed by the compressor; a pressure reducer disposed downstream of the heat exchanger and reducing a pressure of fluid cooled by the heat exchanger; and a combination of a first temperature sensor disposed upstream of a cold fluid channel of the heat exchanger and a fourth temperature sensor disposed downstream of a hot fluid channel of the heat exchanger, combination of a second temperature sensor disposed downstream of the cold fluid channel of the heat exchanger and a third temperature sensor disposed upstream of the hot fluid channel of the heat exchanger, or combination of a first pressure sensor disposed upstream of the hot fluid channel of the heat exchanger and a second pressure sensor disposed downstream of the hot fluid channel of the heat exchanger.

A cold energy recovery facility includes a liquid hydrogen tank configured to store liquid hydrogen a first circuit configured to circulate a first working medium, a second circuit configured to circulate a second working medium having a freezing point higher than the first working medium, a first turboexpander provided in the first circuit, the first turboexpander being configured to be driven by the first working medium in a gas state, a second turboexpander provided in the second circuit, the second turboexpander being configured to be driven by the second working medium in a gas state, a first heat exchanger configured to vaporize the liquid hydrogen from the liquid hydrogen tank by heat exchange with the first working medium, a second heat exchanger configured to vaporize the first working medium in a liquid state by heat exchange with the second working medium, and a third heat exchanger configured to vaporize the second working medium in a liquid state by heat exchange with a heat medium, wherein the first circuit and the first turboexpander form a part of a first thermodynamic cycle that uses the liquid hydrogen as a low-temperature heat source in the first heat exchanger, and the second circuit and the second turboexpander form a part of a second thermodynamic cycle that uses the first working medium as a low-temperature heat source in the second heat exchanger.