An LNG carrier which uses natural gas generated by vaporization of LNG as propulsive fuel and including cargo tank, spray apparatus, and carrier communication device; land-based equipment including land-based communication device and processing device; processing device including: first vapor quantity estimating section which estimates total quantity of natural vapor generated from the LNG remaining in the cargo tank in a case where the LNG carrier is traveling on planned ballast course, based on sea weather data; a second vapor quantity estimating section which estimates a total quantity of spray vapor generated by performing spraying operations in a case where the LNG carrier is traveling on planned ballast course, based on the sea weather data; and heel quantity calculating section which calculates required heel quantity, by summing the total quantity of natural vapor and spray vapor, and the land-based communication device transmits the required heel quantity to the carrier communication device.

A ship including a gas re-vaporizing system according to the present invention includes: a ship body; a vaporizer which is arranged in an upper portion of the ship body, and vaporizes liquefied gas and supplies the vaporized liquefied gas to a demander; and a heat source supply apparatus which is arranged inside the ship body and supplies a heat source to the vaporizer.

According to one aspect of the present disclosure, a floating vessel, particularly an LNG carrier, is described. The floating vessel comprises: a gas turbine engine-generator assembly configured to generate a first electrical power and to supply the first electrical power to an electrical distribution system; a steam turbine engine-generator assembly configured to generate a second electrical power and to supply the second electrical power to the electrical distribution system; a propulsion system configured to propel the floating vessel using a propulsion power supplied from the electrical distribution system, wherein the gas turbine engine-generator assembly is configured to generate a maximum first electrical power between 10 MW and 18 MW, particularly between 14 MW and 15 MW at 25 C. According to a further aspect, a method of operating a floating vessel is described.

A gas processing system according to an embodiment of the present invention includes a heater which is configured to increase a temperature of liquefied gas compulsorily vaporized by a forcing vaporizer before the liquefied gas is joined with Boil Off Gas (BOG) compressed by a BOG compressor.

A ship includes: a boil-off gas heat exchanger installed on a downstream of a storage tank and heat-exchanges a compressed boil-off gas (a first fluid) by a boil-off gas discharged from the storage tank as a refrigerant, to cool the boil-off gas; a compressor installed on a downstream of the boil-off gas heat exchanger and compresses a part of the boil-off gas discharged from the storage tank; an extra compressor installed on a downstream of the boil-off gas heat exchanger and in parallel with the compressor and compresses the other part of the boil-off gas discharged from the storage tank; a refrigerant heat exchanger which additionally cools the first fluid which is cooled by the boil-off gas heat exchanger; and a refrigerant decompressing device which expands a second fluid, which is sent to the refrigerant heat exchanger, and then sends the second fluid back to the refrigerant heat exchanger.

A ship includes: a boil-off gas heat exchanger which is installed on a downstream of a storage tank and heat-exchanges a compressed boil-off gas (a first fluid) by a boil-off gas discharged from the storage tank as a refrigerant to cool the boil-off gas; a compressor installed on a downstream of the boil-off gas heat exchanger and compresses a part of the boil-off gas from the storage tank; an extra compressor which is installed on a downstream of the boil-off gas heat exchanger and in parallel with the compressor and compresses the other part of the boil-off gas from the storage tank; a refrigerant heat exchanger which additionally cools the first fluid; and a refrigerant decompressing device which expands a second fluid, which is sent to the refrigerant heat exchanger, and then sends the second fluid back to the refrigerant heat exchanger.

A tank state estimating method of estimating a state in a tank at a predetermined point in time on a sailing course of an LNG carrier is provided. The LNG carrier carrying LNG stored in the tank as a cargo. The tank state estimating method includes: a first step of acquiring information related to specification of the tank; a second step of acquiring information related to a state in the tank at a start point of a target section on the course; a third step of acquiring information on a predictive value of liquid fluctuation of the LNG in the tank during the section, the predictive value being obtained on a basis of a weather forecasting value during the section and information on the weather forecasting value; and a fourth step of calculating the state in the tank at an end point of the section by thermal transfer calculation based on thermodynamics on a basis of the information acquired in the first to third steps in assuming that a heat input to the tank during the section is used for vaporization of the LNG in the tank.

A ship including a liquefied gas storage tank includes: first and second compressors which compresse a boil-off gas discharged from a storage tank; a boost compressor which compresses one part of the boil-off gas that is compressed by at least any one of the first compressor and/or the second compressor; a first heat exchanger which heat exchanges the boil-off gas compressed by the boost compressor and the boil-off gas discharged from the storage tank; a refrigerant decompressing device which expands the other part of the boil-off gas that is compressed by at least any one of the first compressor and/or the second compressor; a second heat exchanger which cools, by a fluid expanded by the refrigerant decompressing device as a refrigerant; and an additional compressor which is compresses the refrigerant that passes through the refrigerant decompressing device and second heat exchanger.

An apparatus, system and method for capture, utilization and sendout of latent heat in boil off gas (BOG) onboard a cryogenic storage vessel is described. A liquefied gas vessel comprises a cryogenic cargo tank onboard a liquefied gas vessel, the cargo tank comprising a liquefied gas and a BOG, a latent heat exchanger fluidly coupled to a stream of the liquefied gas and a stream of the BOG, wherein the latent heat exchanger transfers a heat between the BOG stream and the liquefied gas stream to produce a condensed BOG, means for combining the condensed BOG and the liquefied gas stream to obtain a combined stream, the means for combining the condensed BOG and the liquefied gas stream fluidly coupled to the latent heat exchanger, and a liquefied gas regasifier onboard the vessel and fluidly coupled to the combined stream, wherein the liquefied gas regasifier regasifies the combined stream.

A system for reliquefying a boil off gas generated in a storage tank includes a first compressor compressing a partial amount (hereinafter, referred to as fluid a) of boil off gas discharged from the storage tank, a second compressor compressing another partial amount (hereinafter, referred to as fluid b) of boil off gas discharged from the storage tank, a second expanding unit expanding a partial amount (hereinafter, referred to as fluid c) of a flow formed as the fluid a and the fluid b join, a heat-exchanger cooling another partial amount (hereinafter, referred to as fluid d) of the flow formed as the fluid a and the fluid b join, and a first expanding unit expanding the fluid d cooled by the heat-exchanger, wherein the heat-exchanger heat-exchanges the fluid d with the fluid c as a coolant expanded by the second expanding unit to cool the fluid d.