Ships

Abstract

The ship of the present invention comprises a cargo tank for storing liquefied gas to be transported as cargo of the ship, a reforming section to which methane, carbon dioxide and water are supplied and which produces synthesis gas containing hydrogen and carbon monoxide, an FT treatment section to which the synthesis gas produced in the reforming section is supplied and which converts the synthesis gas into liquid hydrocarbons, and a gas discharge line connecting the cargo tank and the reforming section, wherein evaporated gas generated from the liquefied gas in the cargo tank is supplied from the gas discharge line to the reforming section, and synthesis gas is produced.

Description

[Technical Field]

[0001] The present invention relates to a ship, and more particularly to a ship in which evaporated gas generated from liquefied gas in a cargo tank is supplied to a reforming section to generate synthesis gas, and this synthesis gas is converted into liquid hydrocarbons in an FT processing section to supply the liquid hydrocarbons to onboard consumers as fuel. [Background technology]

[0002] As global warming becomes more serious, efforts are being made around the world to reduce greenhouse gas emissions.

[0003] With the 1997 Kyoto Protocol, which stipulated the obligations of developed countries to reduce greenhouse gas emissions, set to expire in 2020, the Paris Climate Change Accord was adopted at the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change held in Paris, France in December 2015, and came into effect in November 2016. Under this agreement, the 195 signatory countries agreed to take various measures to reduce greenhouse gas emissions.

[0004] In line with this global trend, there is growing interest in renewable energy (or regenerative energy) such as wind power, sunlight, solar heat, bioenergy, tidal power, and geothermal energy as non-polluting alternatives to fossil fuels and nuclear power, and various technological developments are being carried out in these fields.

[0005] The International Maritime Organization (IMO) is a specialized agency of the United Nations established for the purpose of international harmonization of shipping routes, traffic regulations, port facilities, etc. It predicts that greenhouse gas emissions from ships worldwide will increase from 2.7% of the 2007 level to 12-18% by 2050, and in order to prevent air pollution from ships, it added "Prevention of Air Pollution" to Annex VI of the MARPOL Convention, and designated SOx (sulfur oxides), NOx (nitrogen oxides), ODS (ozone-depleting substances), etc. as substances subject to regulation.

[0006] For this reason, in recent years, technology that uses liquefied gases such as LNG, LPG, CNG, and DME as ship fuels has been attracting attention. In particular, LNG emits more than 20% less carbon dioxide than petroleum fuels such as bunker C oil, and emits almost no nitrogen oxides or sulfur oxides, which are the main causes of air pollution, so it is valued as a fuel with superior environmental benefits compared to other fossil fuels. For this reason, with the strengthening of international emission regulations, an increasing number of ships, other than LPG and LNG carriers, are using LNG as a propulsion fuel.

[0007] Although LNG is considered to be more environmentally friendly than other fossil fuels, carbon dioxide is still emitted when LNG is burned, and therefore, carbon dioxide is emitted during the operation of ships that use LNG as fuel. Summary of the Invention [Problem to be solved by the invention]

[0008] The International Maritime Organization (IMO) has set a goal of reducing greenhouse gas emissions by 50% compared to 2008 levels by 2050, and by 100% (GHG Zero Emissions) by 2100, and it is expected that regulations will be strengthened in each country and region in response to this goal.

[0009] The IMO's Energy Efficiency Design Index (EEDI) is a set of carbon dioxide reduction regulations for newly constructed ships. The initial EEDI publication called for EEDI Phase 1, which required a 10% reduction in 2015 carbon dioxide emissions based on 2013-2015 CO2 emissions. The regulations were then strengthened every five years, with EEDI Phase 3 scheduled for 2025. However, for LPG carriers, EEDI Phase 2 was applied, followed by EEDI Phase 3 two years later in 2022. Ships ordered from 2030 onward were required to achieve a 40% reduction in CO2 emissions compared to ships ordered by 2008, and a 50% reduction by 2050. As such, amid growing international concern about climate change and greenhouse gas emissions, CO2 emissions regulations for ships are rapidly becoming stricter.

[0010] Accompanying this trend toward stricter regulations, various technological developments are underway, including the development of environmentally friendly fuel technologies that do not emit carbon dioxide, and technologies that capture carbon dioxide from fossil fuel combustion gases and convert or liquefy it into methane, methanol, etc. In particular, because the use of fossil fuels is unavoidable until economical renewable energy technologies are developed, there is a need for technological developments that capture and effectively process the carbon dioxide generated by the use of fossil fuels.

[0011] On the other hand, LNG, LPG, liquefied carbon dioxide (LCO2), etc. are cooled and liquefied to facilitate storage and transportation on ships. However, heat transferred to the cargo tank during transportation causes the liquefied gas to continue to vaporize naturally, generating boil-off gas (BOG). The generation of boil-off gas in the cargo tank increases the pressure inside the cargo tank, and if the pressure inside the cargo tank exceeds the set safe pressure, it may lead to tank rupture. Furthermore, since boil-off gas is a type of cargo loss, it is a serious problem from the perspective of liquefied gas transportation efficiency, and a method for safely and effectively disposing of boil-off gas generated in cargo tanks is required.

[0012] An object of the present invention is to provide a method that can effectively treat carbon dioxide and also can effectively treat evaporative gases generated in cargo tanks. [Means for solving the problem]

[0013] In order to solve the above problems, the ship of the present invention comprises a cargo tank for storing liquefied gas to be transported as cargo on the ship, a reforming unit that is supplied with methane, carbon dioxide, and water and produces a synthesis gas containing hydrogen and carbon monoxide, an FT treatment unit that is supplied with the synthesis gas produced in the reforming unit and converts the synthesis gas into liquid hydrocarbons, and a gas discharge line that connects the cargo tank and the reforming unit, and is characterized in that evaporated gas generated from the liquefied gas in the cargo tank is supplied to the reforming unit through the gas discharge line, and synthesis gas is produced.

[0014] Preferably, the ship is an LNG carrier and the liquefied gas in the cargo tank is LNG, the evaporated gas generated from the LNG in the cargo tank is supplied to the reforming section through a gas discharge line, and the liquid hydrocarbons generated in the FT treatment section are supplied as fuel to onboard consumers.

[0015] Preferably, the ship further comprises a carbon dioxide tank for storing liquefied carbon dioxide gas, and a fuel supply line for connecting the carbon dioxide tank to the reforming unit and supplying evaporated gas generated from the liquefied carbon dioxide gas in the carbon dioxide tank to the reforming unit.

[0016] Preferably, the system further includes a liquefied carbon dioxide supply pump provided in the carbon dioxide tank for supplying liquefied carbon dioxide, and an in-line mixer provided in the fuel supply line, and when the amount of evaporated gas generated in the carbon dioxide tank is less than the amount of carbon dioxide required in the reforming section, the liquefied carbon dioxide gas pumped by the liquefied carbon dioxide supply pump is mixed with the evaporated gas in the in-line mixer and supplied to the reforming section.

[0017] Preferably, the system further includes a liquid supply line that supplies LNG stored in the cargo tank to the outside of the cargo tank, and an LNG supply pump that is provided in the cargo tank and supplies LNG to the liquid supply line, and when the amount of evaporated gas generated in the cargo tank is less than the amount of methane required in the reforming section, LNG pressurized by the LNG supply pump is supplied to the reforming section.

[0018] Preferably, the ship further comprises an LNG pressure pump provided in the liquid supply line for pressurizing LNG in accordance with the fuel supply pressure of the main propulsion engine, and a forced vaporizer for heating the LNG pressurized by the LNG pressure pump in accordance with the fuel supply temperature of the main propulsion engine and supplying it to the main propulsion engine, and the LNG consumed on board is at least one of a power generation engine and a boiler.

[0019] Preferably, the onboard consumers are at least one of a power generation engine and a boiler, and the main propulsion engine.

[0020] Preferably, the ship is a liquefied carbon dioxide gas carrier, the liquefied gas in the cargo tank is liquefied carbon dioxide gas, and the ship further includes a fuel tank for storing LNG to be supplied as fuel to onboard consumers.

[0021] Preferably, the fuel cell further includes a gas supply line connecting the fuel tank and the reforming section to supply evaporated gas generated from LNG in the fuel tank to the reforming section.

[0022] Preferably, the system further includes a liquid supply line that supplies LNG stored in the fuel tank to the outside of the fuel tank, and an LNG supply pump that is provided in the fuel tank and supplies LNG to the liquid supply line, and when the amount of evaporated gas generated in the fuel tank is less than the amount of methane required in the reforming section, LNG pressurized by the LNG supply pump is supplied to the reforming section.

[0023] Preferably, the ship further comprises an LNG pressure pump provided in the liquid supply line for pressurizing LNG in accordance with the fuel supply pressure of the main propulsion engine, and a forced vaporizer for heating the LNG pressurized by the LNG pressure pump in accordance with the fuel supply temperature of the main propulsion engine and supplying it to the main propulsion engine, and the LNG consumed on board is at least one of a power generation engine and a boiler.

[0024] Preferably, the ship further comprises a liquefied carbon dioxide supply pump provided in the cargo tank for supplying liquefied carbon dioxide, and an in-line mixer provided in the gas discharge line, and when the amount of evaporated gas generated in the cargo tank is less than the amount of carbon dioxide required in the reforming section, the liquefied carbon dioxide pressurized by the liquefied carbon dioxide supply pump is mixed with the evaporated gas in the in-line mixer and supplied to the reforming section, and the onboard consumers are at least one of the power generation engine and boiler, and the main propulsion engine.

[0025] Preferably, carbon dioxide contained in exhaust gas generated in at least one of the power generation engine, the boiler, and the main propulsion engine is recovered and supplied to the reforming section. [Effects of the Invention]

[0026] According to the present invention, synthesis gas is produced using evaporated gas generated from LNG in a cargo tank as a raw material, and the synthesis gas is converted into liquid hydrocarbons, which are then supplied as fuel to onboard consumers for processing.

[0027] Furthermore, according to the present invention, by effectively treating the evaporated gas generated from LNG in the cargo tank, the pressure increase in the cargo tank can be suppressed, thereby ensuring the safety of the ship.

[0028] Furthermore, according to the present invention, the evaporated gas (i.e., carbon dioxide gas) generated from the liquefied carbon dioxide gas in the cargo tank is used as a raw material to generate synthetic gas, which is then converted into liquid hydrocarbons and supplied as fuel to onboard consumers for processing.

[0029] Furthermore, according to the present invention, by effectively treating the evaporated gas generated from the liquefied carbon dioxide gas in the cargo tank, the pressure increase inside the cargo tank can be suppressed and the safety of the ship can be ensured. Furthermore, by using the evaporated gas (carbon dioxide gas) as fuel for onboard consumption such as power generation engines, the operating costs of the ship can be reduced and energy efficiency can be improved.

[0030] Furthermore, according to the present invention, carbon dioxide contained in exhaust gases generated by the main engine, power generation engine, etc. is recovered and used as a raw material for synthesis gas, thereby minimizing carbon dioxide emissions during ship operation. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic diagram showing a vessel according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a schematic diagram showing a vessel according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a schematic diagram showing a vessel according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram showing a vessel according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] For a full understanding of the operating advantages and objects attained by the embodiments of the present invention, reference should be made to the accompanying drawings and the contents thereof, which illustrate the embodiments of the present invention.

[0033] Hereinafter, the configuration and operation of an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0034] The ship in the embodiments of the present invention described below refers to any ship equipped with an LNG cargo tank that generates methane gas as an evaporative gas, and includes, for example, self-propelled ships such as LNG carriers and LNGRVs (Regasification Vessels), as well as floating offshore structures that do not have self-propelling capabilities, such as LNG FPSOs (Floating Production Storage Offloading).

[0035] Figures 1 and 2 show ships according to first and second embodiments of the present invention. More specifically, Figure 1 is a schematic diagram of a fuel supply system provided on an LNG carrier according to the first embodiment of the present invention, and Figure 2 is a schematic diagram of a fuel supply system provided on an LNG carrier according to the second embodiment of the present invention.

[0036] Referring to FIG. 1, the fuel supply system provided on the LNG carrier of the first embodiment includes a plurality of cargo tanks CTa, CTb, and CTc in which LNG to be transported as cargo of the ship is stored, a reforming unit 100 that is supplied with methane, carbon dioxide, and water and produces a synthesis gas containing hydrogen and carbon monoxide, an FT treatment unit 200 that is supplied with the synthesis gas produced in the reforming unit 100 and converts the synthesis gas into liquid hydrocarbons, and a gas discharge line BL that connects the cargo tanks CTa, CTb, and CTc to the reforming unit 100.

[0037] The evaporated gas (mainly methane gas) generated from the LNG in each cargo tank CTa, CTb, and CTc is supplied to the reforming section 100 via the gas discharge line BL, and the liquid hydrocarbons produced in the FT processing section 200 are supplied as fuel to the onboard consumer C.

[0038] The LNG carrier is provided with a carbon dioxide tank FT for storing liquefied carbon dioxide (LCO2) in order to supply the carbon dioxide used in the reforming section 100 to generate synthesis gas.

[0039] The carbon dioxide tank FT is composed of a pressure vessel capable of maintaining its internal pressure at or above the triple point of carbon dioxide, and stores carbon dioxide in a liquid state. The triple point of carbon dioxide is approximately 5.18 bara, or -56.7°C. Normally, when carbon dioxide gas is cooled at atmospheric pressure, it changes phase to a solid and becomes dry ice. Therefore, by providing a carbon dioxide tank FT composed of a pressure vessel and maintaining the pressure inside the carbon dioxide tank FT at or above the triple point of carbon dioxide, and maintaining the temperature inside the carbon dioxide tank FT at a low temperature below the boiling point of carbon dioxide, it is possible to store carbon dioxide in a liquid state, which is more suitable for storage and transportation than a solid state.

[0040] The evaporated gas (carbon dioxide gas) generated from the liquefied carbon dioxide gas in the carbon dioxide tank FT is discharged from the carbon dioxide tank FT and supplied to the reforming section 100, where it is used as a raw material for synthesis gas. For this reason, the carbon dioxide tank FT and the reforming section 100 are connected by a fuel supply line FL.

[0041] The reforming section 100 is supplied with methane gas, which is an evaporated gas of LNG, supplied from each cargo tank CTa, CTb, and CTc via a gas discharge line BL, carbon dioxide (carbon dioxide gas) supplied from a carbon dioxide tank FT via a fuel supply line FL, and water, and generates synthesis gas containing hydrogen and carbon monoxide by reforming gasification as follows.

[0042] 2CH4+CO2+H2O→5H2+3CO

[0043] The synthesis gas produced in the reforming section 100 is supplied to the FT processing section 200, where it is converted into liquid hydrocarbons such as diesel and naphtha (GTL; Gas to Liquid) by the Fischer-Tropsch Synthesis Reaction in the presence of a catalyst such as cobalt (Co) or iron (Fe). The liquid hydrocarbons, including diesel, produced in the FT processing section 200 are supplied to the onboard consumer C as fuel.

[0044] 5H2+3CO→GTL Fuel

[0045] In the LNG carrier of the first embodiment, LNG stored in cargo tanks CTa, CTb, and CTc is supplied as fuel to the main engine ME for propelling the ship, and liquid hydrocarbons produced in the reforming section 100 and the FT processing section 200 are supplied as fuel to onboard consumption destinations C such as power generation engines and boilers (Aux. Boilers).

[0046] The LNG carrier of the first embodiment is also provided with a liquid supply line LL that supplies LNG stored in the cargo tanks CTa, CTb, and CTc to the outside of the cargo tanks CTa, CTb, and CTc, and an LNG supply pump CP is provided in the cargo tank CTa that supplies LNG to the liquid supply line LL. The liquid supply line LL is provided with an LNG pressure pump 300 that pressurizes LNG in accordance with the fuel supply pressure of the main propulsion engines ME, and a forced vaporizer 350 that heats the LNG pressurized by the LNG pressure pump 300 in accordance with the fuel supply temperature of the main engines ME and supplies the LNG to the main engines ME. These devices allow the pressurized and heated LNG discharged from the cargo tanks CTa, CTb, and CTc to be supplied to the main engines ME as fuel.

[0047] Furthermore, when the amount of evaporated gas generated from the LNG in the cargo tanks CTa, CTb, and CTc is less than the amount of methane required by the reforming section 100, LNG pressure-fed by the LNG supply pump CP is supplied to the reforming section 100. For this reason, the liquid supply line LL branches into a line LL1 and a line LL2 upstream of the LNG pressure pump 300, with the line LL1 connected to the reforming section 100 and the line LL2 connected to the LNG pressure pump 300.

[0048] On the other hand, when the evaporated gas (carbon dioxide gas) generated in the carbon dioxide tank FT is supplied to the reforming section 100, if the amount of evaporated gas generated in the carbon dioxide tank FT is less than the amount of carbon dioxide required in the reforming section 100, the liquefied carbon dioxide gas delivered by the liquefied carbon dioxide gas supply pump FP provided in the carbon dioxide tank FT is mixed with the evaporated gas by the inline mixer 150 provided in the fuel supply line FL and supplied to the reforming section 100.

[0049] Furthermore, hydrocarbon fuels are used in the propulsion main engine ME, the power generation engine, and the boiler, and their exhaust gases contain carbon dioxide. The carbon dioxide contained in these exhaust gases may be recovered and supplied to the reforming unit 100, or the recovered carbon dioxide may be liquefied and stored in the carbon dioxide tank FT.

[0050] The fuel supply system provided on the LNG carrier of the second embodiment shown in FIG. 2 is configured so that the liquid hydrocarbons produced in the FT processing unit 200 are also supplied to the main engines ME for propulsion.

[0051] That is, in the above-described first embodiment, LNG is supplied from cargo tanks CTa, CTb, and CTc to the main engine ME, and liquid hydrocarbons are supplied to the power generation engine, boilers, etc., but in the second embodiment, the onboard consumers to which liquid hydrocarbons are supplied include the main engine in addition to the power generation engine and boilers.

[0052] In the second embodiment, the liquid supply line LL connected to the cargo tanks CTa, CTb, and CTc does not branch, but is connected only to the reforming section 100, and the LNG pressurized by the LNG supply pump CP is supplied to the reforming section 100 and used as a raw material for synthesis gas and liquid hydrocarbons.

[0053] The reforming section 100 is first supplied with evaporated gas generated from LNG in multiple cargo tanks CTa, CTb, and CTc, and if the amount of evaporated gas generated in the cargo tanks CTa, CTb, and CTc is less than the amount of methane required by the reforming section 100, LNG pressurized by the LNG supply pump CP is supplied to the reforming section 100.

[0054] As described above, in the fuel supply system installed on the LNG carrier of the first and second embodiments, the pressure inside the cargo tanks CTa, CTb, CTc is safely maintained by effectively processing the evaporative gas generated in the cargo tanks CTa, CTb, CTc of the LNG carrier, and by producing the necessary fuel on board and supplying it to the onboard consumer C, the operating costs of the ship can be reduced and carbon dioxide emissions during ship operation can be reduced.

[0055] The ships of the third and fourth embodiments of the present invention described below are liquefied carbon dioxide carriers, and are any type of ship that is provided with cargo tanks for storing liquefied carbon dioxide and fuel tanks for storing LNG, which is used as a raw material for synthesis gas and as fuel on board the ship.

[0056] Figures 3 and 4 show ships according to third and fourth embodiments of the present invention. More specifically, Figure 3 is a schematic diagram of an evaporative gas treatment system provided on a liquefied carbon dioxide carrier according to the third embodiment of the present invention, and Figure 4 is a schematic diagram of an evaporative gas treatment system provided on a liquefied carbon dioxide carrier according to the fourth embodiment of the present invention.

[0057] As shown in Figures 3 and 4, the evaporative gas treatment system installed on the liquefied carbon dioxide carrier of the third and fourth embodiments is installed to treat evaporative gas (carbon dioxide gas) generated in a cargo tank that stores liquefied carbon dioxide gas transported as cargo on the ship.

[0058] The liquefied carbon dioxide carrier is provided with a plurality of cargo tanks CTa, CTb, and CTc in which liquefied carbon dioxide is stored, and a fuel tank FT in which LNG is stored to be used as fuel on board. In the third and fourth embodiments, the LNG stored in the fuel tank FT is supplied as fuel to the main engine ME for propelling the ship.

[0059] The evaporative gas treatment system installed on a liquefied carbon dioxide carrier according to a third embodiment of the present invention includes a reforming section 100 that is supplied with methane, carbon dioxide, and water and produces a synthesis gas containing hydrogen and carbon monoxide, an FT treatment section 200 that is supplied with the synthesis gas produced in the reforming section 100 and converts the synthesis gas into liquid hydrocarbons, and a gas discharge line BL that connects cargo tanks CTa, CTb, and CTc to the reforming section 100. Also included is a gas supply line GL that connects a fuel tank FT to the reforming section 100, and evaporative gas generated from LNG in the fuel tank FT is supplied to the reforming section 100.

[0060] The evaporated gas (carbon dioxide) generated from the liquefied carbon dioxide gas in the cargo tanks CTa, CTb, and CTc is discharged from the cargo tanks CTa, CTb, and CTc and supplied to the reforming section 100 via the gas discharge line BL, where it is used as a raw material for synthesis gas.

[0061] Each cargo tank CTa, CTb, and CTc is constructed as a pressure vessel capable of maintaining its internal pressure at or above the triple point of carbon dioxide, and stores carbon dioxide in a liquid state. The triple point of carbon dioxide is approximately 5.18 bara and -56.7°C, and when carbon dioxide is cooled at atmospheric pressure, it typically changes phase to solid and becomes dry ice. Therefore, by providing cargo tanks CTa, CTb, and CTc constructed as pressure vessels and maintaining the internal pressure at or above the triple point of carbon dioxide, and maintaining the internal temperature at a low temperature below the boiling point of carbon dioxide, carbon dioxide can be stored in a liquid state, which is more suitable for storage and transportation than a solid state.

[0062] The evaporated gas generated from the liquefied carbon dioxide gas in the cargo tanks CTa, CTb, and CTc is discharged from the cargo tanks CTa, CTb, and CTc and supplied to the reforming unit 100, where it is used as a raw material for synthesis gas. For this reason, each of the cargo tanks CTa, CTb, and CTc and the reforming unit 100 are connected by a gas discharge line BL.

[0063] The reforming section 100 is supplied with methane gas, which is an evaporated gas of LNG, supplied from the fuel tank FT via the gas supply line GL, carbon dioxide (carbon dioxide) supplied from each cargo tank CTa, CTb, and CTc via the gas discharge line BL, and water, and generates synthesis gas containing hydrogen and carbon monoxide by reforming gasification as follows.

[0064] 2CH4+CO2+H2O→5H2+3CO

[0065] The synthesis gas produced in the reforming section 100 is supplied to the FT processing section 200, where it is converted into liquid hydrocarbons such as diesel and naphtha (GTL; Gas to Liquid) by the Fischer-Tropsch synthesis reaction in the presence of a catalyst such as cobalt (Co) or iron (Fe). The liquid hydrocarbons, including diesel, produced in the FT processing section 200 are supplied to the onboard consumer C as fuel.

[0066] 5H2+3CO→GTL Fuel

[0067] In the liquefied carbon dioxide carrier of the third embodiment, LNG stored in a fuel tank FT is supplied as fuel to the main engine ME for propelling the ship, and liquid hydrocarbons produced in the reforming section 100 and the FT processing section 200 are supplied as fuel to onboard consumption destinations C such as a power generation engine and a boiler (Aux. Boiler).

[0068] The liquefied carbon dioxide carrier of the third embodiment is provided with a liquid supply line FL that supplies LNG stored in a fuel tank FT to the outside of the fuel tank FT, and the fuel tank FT is provided with an LNG supply pump FP that supplies LNG to the liquid supply line FL. The liquid supply line FL is provided with an LNG pressure pump 300 that pressurizes the LNG in accordance with the fuel supply pressure of the main propulsion engine ME, and a forced vaporizer 350 that heats the LNG pressurized by the LNG pressure pump 300 in accordance with the fuel supply temperature of the main engine ME and supplies it to the main engine ME, and these devices allow the pressurized and heated LNG discharged from the fuel tank FT to be supplied to the main engine ME as fuel.

[0069] When the evaporated gas generated from the LNG in the fuel tank FT is supplied to the reforming section 100 as a raw material for synthesis gas, if the amount of evaporated gas generated in the fuel tank FT is less than the amount of methane required by the reforming section 100, LNG pressurized by the LNG supply pump FP is supplied to the reforming section 100. For this reason, the liquid supply line FL branches into a line FL1 and a line FL2 upstream of the LNG pressure pump 300, and the line FL1 is connected to the reforming section 100 and the line FL2 is connected to the LNG pressure pump 300.

[0070] On the other hand, if the amount of evaporated gas generated from the liquefied carbon dioxide gas in the cargo tanks CTa, CTb, and CTc is less than the amount of carbon dioxide required in the reforming section 100, a portion of the liquefied carbon dioxide gas stored in the cargo tanks CTa, CTb, and CTc is supplied to the reforming section 100.

[0071] Furthermore, hydrocarbon fuels are used in the propulsion main engine ME, the power generation engines, and the boilers, and their exhaust gases contain carbon dioxide. The carbon dioxide contained in these exhaust gases may be recovered and supplied to the reforming unit 100, or the recovered carbon dioxide may be liquefied and stored in the cargo tanks CTa, CTb, and CTc.

[0072] Furthermore, the liquefied carbon dioxide carrier of this embodiment may further be provided with a storage tank (not shown) for storing liquid hydrocarbons that remain unused after being supplied as fuel to the onboard consumer C.

[0073] The evaporative gas treatment system provided on the liquefied carbon dioxide gas carrier of the fourth embodiment shown in FIG. 4 is configured so that the liquid hydrocarbons produced in the FT treatment unit 200 are also supplied to the main engine ME for propulsion.

[0074] That is, in the above third embodiment, LNG is supplied from the fuel tank FT to the main engine ME, and liquid hydrocarbons are supplied to the power generation engine, boiler, etc., but in the fourth embodiment, the onboard consumers to which liquid hydrocarbons are supplied include the main engine in addition to the power generation engine and boiler.

[0075] In the fourth embodiment, the liquid supply line FL connected to the fuel tank FT does not branch off but is connected only to the reforming section 100, and the LNG pumped by the LNG supply pump FP is supplied to the reforming section 100 and used as a raw material for synthesis gas and liquid hydrocarbons.

[0076] Moreover, in the fourth embodiment, a liquefied carbon dioxide supply pump CP that supplies liquefied carbon dioxide is provided in the cargo tank CTa, and an in-line mixer 150 is provided in the gas discharge line BL. Evaporated gas generated from liquefied carbon dioxide in the multiple cargo tanks CTa, CTb, and CTc is first supplied to the reforming section 100, and if the amount of evaporated gas generated in the cargo tanks CTa, CTb, and CTc is less than the amount of carbon dioxide required by the reforming section 100, the liquefied carbon dioxide pressure-fed by the liquefied carbon dioxide supply pump CP is mixed with the evaporated gas in the in-line mixer 150 and supplied to the reforming section 100.

[0077] As described above, in the evaporative gas treatment system installed on the liquefied carbon dioxide carrier of the third and fourth embodiments, during the transportation of liquefied carbon dioxide, the evaporative gas generated from the liquefied carbon dioxide in the cargo tanks CTa, CTb, and CTc of the liquefied carbon dioxide carrier is effectively treated without being released into the atmosphere, thereby safely maintaining the pressure in the cargo tanks CTa, CTb, and CTc, and by generating the necessary fuel on board from carbon dioxide and supplying it to the onboard consumer C, the operating costs of the ship can be reduced and carbon dioxide emissions during ship operation can be reduced.

[0078] The present invention is not limited to the above-described embodiments, and it will be obvious to those skilled in the art to which the present invention pertains that various changes or modifications can be made without departing from the technical gist of the present invention.

Claims

1. Cargo tanks for storing liquefied gases carried as cargo on the ship; and a reforming section that receives methane, carbon dioxide, and water and produces a synthesis gas containing hydrogen and carbon monoxide; and an FT processing unit that receives the synthesis gas produced in the reforming unit and converts the synthesis gas into liquid hydrocarbons; and a gas discharge line connecting the cargo tank and the reforming unit; A ship characterized in that evaporated gas generated from liquefied gas in a cargo tank is supplied to a reforming section through a gas discharge line, and synthetic gas is produced.

2. the ship is an LNG carrier and the liquefied gas in the cargo tank is LNG; Evaporated gas generated from the LNG in the cargo tank is supplied to the reforming unit through the gas discharge line, 2. The ship according to claim 1, wherein the liquid hydrocarbons produced in the FT treatment unit are supplied as fuel to onboard consumers.

3. a carbon dioxide tank provided on the ship for storing liquefied carbon dioxide gas; and 3. The vessel according to claim 2, further comprising: a fuel supply line connecting the carbon dioxide tank with the reforming unit, for supplying evaporated gas generated from the liquefied carbon dioxide gas in the carbon dioxide tank to the reforming unit.

4. a liquefied carbon dioxide gas supply pump provided in the carbon dioxide tank and supplying liquefied carbon dioxide gas; and an in-line mixer provided in the fuel supply line; 4. A ship as described in claim 3, characterized in that when the amount of evaporated gas generated in the carbon dioxide tank is less than the amount of carbon dioxide required in the reforming section, liquefied carbon dioxide gas pressurized by a liquefied carbon dioxide gas supply pump is mixed with the evaporated gas in an in-line mixer and supplied to the reforming section.

5. a liquid supply line that supplies the LNG stored in the cargo tank to the outside of the cargo tank; and an LNG supply pump provided in the cargo tank for supplying LNG to the liquid supply line; 5. The ship according to claim 4, wherein when the amount of evaporated gas generated in the cargo tank is less than the amount of methane required in the reforming section, LNG pressurized by an LNG supply pump is supplied to the reforming section.

6. an LNG pressure pump provided in the liquid supply line for pressurizing LNG in accordance with the fuel supply pressure of the main propulsion engine; and a forced vaporizer that heats the LNG pressurized by the LNG pressure pump in accordance with a fuel supply temperature of the main propulsion engine and supplies the LNG to the main propulsion engine; 6. The ship according to claim 5, wherein the onboard consumer is at least one of a power generation engine and a boiler.

7. 6. The ship according to claim 5, wherein the onboard consumers are at least one of a power generation engine and a boiler, and a main propulsion engine.

8. The ship is a liquefied carbon dioxide gas carrier, and the liquefied gas in the cargo tank is liquefied carbon dioxide gas, 2. The vessel of claim 1, further comprising a fuel tank for storing LNG to be supplied as fuel to onboard consumers.

9. 9. The ship according to claim 8, further comprising: a gas supply line connecting the fuel tank and the reforming unit, for supplying evaporated gas generated from LNG in the fuel tank to the reforming unit.

10. a liquid supply line that supplies LNG stored in the fuel tank to the outside of the fuel tank; and an LNG supply pump provided in the fuel tank for supplying LNG to the liquid supply line; 10. The ship according to claim 9, wherein when the amount of evaporated gas generated in the fuel tank is less than the amount of methane required in the reforming section, LNG pressurized by an LNG supply pump is supplied to the reforming section.

11. an LNG pressure pump provided in the liquid supply line for pressurizing LNG in accordance with the fuel supply pressure of the main propulsion engine; and a forced vaporizer that heats the LNG pressurized by the LNG pressure pump in accordance with a fuel supply temperature of the main propulsion engine and supplies the LNG to the main propulsion engine; 11. The ship according to claim 10, wherein the onboard consumer is at least one of a power generation engine and a boiler.

12. a liquefied carbon dioxide gas supply pump provided in the cargo tank and configured to supply liquefied carbon dioxide gas; and an in-line mixer provided in the gas discharge line; When the amount of evaporated gas generated in the cargo tank is less than the amount of carbon dioxide required in the reforming section, liquefied carbon dioxide gas pressure-fed by a liquefied carbon dioxide gas supply pump is mixed with the evaporated gas in an in-line mixer and supplied to the reforming section, 11. The ship according to claim 10, wherein the onboard consumers are at least one of a power generation engine and a boiler, and a main propulsion engine.

13. carbon dioxide contained in exhaust gas generated in at least one of the power generation engine, the boiler, and the main propulsion engine is recovered and supplied to the reforming section, 13. A watercraft according to any one of claims 6, 7, 11 and 12.

Images