Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C13/00—Details of vessels or of the filling or discharging of vessels
  • F17C13/005—Details of vessels or of the filling or discharging of vessels for medium-size and small storage vessels not under pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/01—Shape
  • F17C2201/0104—Shape cylindrical
  • F17C2201/0109—Shape cylindrical with exteriorly curved end-piece
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/03—Orientation
  • F17C2201/035—Orientation with substantially horizontal main axis
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/05—Size
  • F17C2201/054—Size medium (>1 m3)
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/03—Thermal insulations
  • F17C2203/0304—Thermal insulations by solid means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0602—Wall structures; Special features thereof
  • F17C2203/0612—Wall structures
  • F17C2203/0626—Multiple walls
  • F17C2203/0629—Two walls
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
  • F17C2205/01—Mounting arrangements
  • F17C2205/0153—Details of mounting arrangements
  • F17C2205/0176—Details of mounting arrangements with ventilation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
  • F17C2205/03—Fluid connections, filters, valves, closure means or other attachments
  • F17C2205/0302—Fittings, valves, filters, or components in connection with the gas storage device
  • F17C2205/0323—Valves
  • F17C2205/0332—Safety valves or pressure relief valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
  • F17C2205/03—Fluid connections, filters, valves, closure means or other attachments
  • F17C2205/0302—Fittings, valves, filters, or components in connection with the gas storage device
  • F17C2205/0338—Pressure regulators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2221/00—Handled fluid, in particular type of fluid
  • F17C2221/03—Mixtures
  • F17C2221/032—Hydrocarbons
  • F17C2221/033—Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
  • F17C2223/0146—Two-phase
  • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
  • F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, PLNG
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
  • F17C2223/033—Small pressure, e.g. for liquefied gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/04—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by other properties of handled fluid before transfer
  • F17C2223/042—Localisation of the removal point
  • F17C2223/046—Localisation of the removal point in the liquid
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2225/00—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel
  • F17C2225/04—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel characterised by other properties of handled fluid after transfer
  • F17C2225/042—Localisation of the filling point
  • F17C2225/043—Localisation of the filling point in the gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2225/00—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel
  • F17C2225/04—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel characterised by other properties of handled fluid after transfer
  • F17C2225/042—Localisation of the filling point
  • F17C2225/043—Localisation of the filling point in the gas
  • F17C2225/044—Localisation of the filling point in the gas at several points, e.g. with a device for recondensing gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/01—Propulsion of the fluid
  • F17C2227/0107—Propulsion of the fluid by pressurising the ullage
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/01—Propulsion of the fluid
  • F17C2227/0128—Propulsion of the fluid with pumps or compressors
  • F17C2227/0135—Pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/03—Heat exchange with the fluid
  • F17C2227/0302—Heat exchange with the fluid by heating
  • F17C2227/0309—Heat exchange with the fluid by heating using another fluid
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/03—Heat exchange with the fluid
  • F17C2227/0367—Localisation of heat exchange
  • F17C2227/0388—Localisation of heat exchange separate
  • F17C2227/0393—Localisation of heat exchange separate using a vaporiser
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/04—Methods for emptying or filling
  • F17C2227/044—Methods for emptying or filling by purging
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/04—Methods for emptying or filling
  • F17C2227/048—Methods for emptying or filling by maintaining residual pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
  • F17C2250/04—Indicating or measuring of parameters as input values
  • F17C2250/0404—Parameters indicated or measured
  • F17C2250/0408—Level of content in the vessel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
  • F17C2250/04—Indicating or measuring of parameters as input values
  • F17C2250/0404—Parameters indicated or measured
  • F17C2250/043—Pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
  • F17C2250/04—Indicating or measuring of parameters as input values
  • F17C2250/0404—Parameters indicated or measured
  • F17C2250/0439—Temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
  • F17C2250/04—Indicating or measuring of parameters as input values
  • F17C2250/0404—Parameters indicated or measured
  • F17C2250/0447—Composition; Humidity
  • F17C2250/0452—Concentration of a product
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
  • F17C2250/06—Controlling or regulating of parameters as output values
  • F17C2250/0605—Parameters
  • F17C2250/0626—Pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2260/00—Purposes of gas storage and gas handling
  • F17C2260/02—Improving properties related to fluid or fluid transfer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2265/00—Effects achieved by gas storage or gas handling
  • F17C2265/03—Treating the boil-off
  • F17C2265/032—Treating the boil-off by recovery
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2265/00—Effects achieved by gas storage or gas handling
  • F17C2265/06—Fluid distribution
  • F17C2265/066—Fluid distribution for feeding engines for propulsion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2270/00—Applications
  • F17C2270/01—Applications for fluid transport or storage
  • F17C2270/0102—Applications for fluid transport or storage on or in the water
  • F17C2270/0105—Ships

Definitions

• the present invention relates to a fuel tank arrangement for such a gas fuelled marine vessel that uses as its sole source of fuel liquefied natural gas (LNG).
• LNG fuel liquefied natural gas
• the present invention is mostly concerned of fulfilling the requirements the pure gas-fuelling sets to the construction of the LNG- fuel tank. More particularly, the present invention relates to such an LNG- fuel tank arrangement that the tank comprises at least one shell, a heat insulation and a tank connection space being formed of a plurality of compartments ar- ranged at an end or at a side of the LNG- fuel tank.
• NG natural gas
• CH4 methane
• NG In liquid form the specific volume is reduced significantly, which allows a reason- able size of storage tanks relative to energy content.
• the burning process of NG is clean. Its high hydrogen-to-coal ratio (the highest among the fossil fuels) means lower CO2 emissions compared with oil-based fuels. When NG is liquefied, all sulphur is removed, which means zero SOx emissions.
• the clean burning properties of NG also significantly reduce NOx and particle emissions compared with oil-based fuels. Particularly in cruise vessels, ferries and so called ro-pax vessels, where passengers are on board, the ab- sence of soot emissions and visible smoke in the exhaust gases of ship's engines is a very important feature.
• Non-pressurized prior art LNG- tanks have normally only a single wall or shell covered with a heat insulation of, for instance, polyurethane.
• Pressurized prior art LNG- tanks have an inner wall or shell of stainless steel and an outer wall or shell spaced at a distance from the inner shell. The inner and outer shells define an insulation space there- between.
• the LNG- tank is provided, for emptying the tank, with at least one pipe of stainless steel connected at its first end to the LNG- tank and at its second end to a tank connection space arranged at a side or at an end of the tank, either as an extension of the tank or as a separate chamber at a short distance from the tank.
• the tank connection space is normally a gas tight enclosure containing all tank connections, fittings, flanges and tank valves. It is constructed of cryogenic temperature resistant materials, it has a bilge well with a high level indicator and a low temperature sensor.
• the tank connection space (TCS) is not normally accessible, it may not be entered by personnel unless checked for sufficient oxygen and absence of explosive atmosphere. For safety reasons the TCS is provided with permanent gas detection, fixed fire detection and mechanical forced ventilation, which changes air 30 times an hour.
• the second type of LNG- tank is the choice for marine vessels, especially for those having at least two engines. It is much more cost- efficient to build a single leakage-free large-sized LNG- tank than a number of smaller tanks with multiplied instrumentation and equipment for the delivery of fuel to each en- gine.
• an object of the present invention is to design such an LNG- fuel tank ar- rangement for a gas fuelled marine vessel that the various pieces of instrumentation and equipment used for handling the LNG- fuel are divided in practical manner into more than one tank connection space.
• Another object of the present invention is to design such an LNG- fuel tank ar- rangement for a gas fuelled marine vessel that a problem in feeding LNG- fuel to one engine is isolated from other engine/s such that the other engine/s may continue their problem-free operation.
• a further object of the present invention is to design such an LNG- fuel tank ar- rangement that the tank connection space thereof is provided with inert atmosphere whenever the TCS is closed, i.e. not occupied by service and/or maintenance personnel.
• At least one object of the present invention is substantially met by a fuel tank arrangement in a gas fuelled marine vessel for storing LNG- fuel, the arrangement corn- prising an LNG- fuel tank, a tank connection space provided in communication with the LNG- fuel tank, the tank connection space being formed of at least three isolated com- partments, i.e. one bunkering compartment and at least two LNG- fuel feed compart- ments.
• the fuel tank arrangement of the present invention offers at least some of the following advantages: • only one LNG- tank needed for storing fuel for one or more engines,
• Figure 1 illustrates schematically a side view of a marine vessel having an LNG- fuel tank of the present invention on the deck thereof
• FIGS. 2a and 2b illustrate schematically two longitudinal and horizontal cross-sectional variations of an LNG- fuel tank in accordance with a preferred embodiment of the present invention
• Figure 3 illustrates schematically a partial cross sectional side view of a tank connection space of the LNG- fuel tank along line A-A of Figure 2a, i.e. the bunkering compartment thereof,
• Figure 4 illustrates schematically a partial cross sectional side view of a tank connection space of the LNG- fuel tank along line B-B of Figure 2a, i.e. a first variation of the LNG- fuel feed compartment thereof,
• Figure 5 illustrates schematically a partial cross sectional side view of a tank connection space of the LNG- fuel tank along line B-B of Figure 2a, i.e. a second variation of the LNG- fuel feed compartment thereof,
• Figure 6 illustrates schematically a further development of the bunkering compartment of the LNG- fuel tank of Figure 3.
• Figure 7 illustrates schematically a further development of the LNG- fuel feed compart- ment of the LNG- fuel tank of Figure 4.
• Figure 1 illustrates schematically and in a very simplified manner a marine vessel 10 with an LNG- fuel tank 12 provided on the deck thereof.
• the LNG- fuel tank may also be positioned below the deck.
• the Figure shows also the internal combustion engine 14 receiving fuel from the LNG- fuel tank 12 and the drive means 16 coupled to both the engine 14 and the propeller 18.
• the drive means may here comprise either a mechanical gear or a generator - electric drive combination.
• FIG. 2a illustrates schematically the basic constructions of the LNG- fuel tank 12 in accordance with a first variation of the preferred embodiment of the present inven- tion.
• the fuel tank 12 is, as an example, formed of an inner shell 20, an outer shell 22 and a heat insulation 24 therebetween.
• a so called tank connection space, or TCS, 26.1 is arranged at an end of the fuel tank 12 .
• the tank connection space 26.1 may as well be located at a side of the LNG- fuel tank, and not necessarily as an exten- sion of the shell of the tank but also at a distance from the shell of the tank, i.e. as a separate chamber at a side or at an end of the LNG- fuel tank.
• the tank connection space 26.1 is, preferably, but not necessarily, provided with heat insulation 28.
• the tank connection space 26.1 is formed of one bunkering compartment 30.1 , and two LNG- fuel feed compartments 70.1 and 70.2.
• FIG. 2b illustrates schematically the basic constructions of the LNG- fuel tank 12 in accordance with a second variation of the preferred embodiment of the present invention.
• the fuel tank 12 is, as already earlier, formed of an inner shell 20, an outer shell 22 and a heat insulation 24 therebetween.
• a so called tank connection space 26.2 is arranged at an end of the fuel tank 12 .
• the tank connection space may as well be located at a side of the LNG- fuel tank, and not necessarily as an extension of the shell of the tank but also at a distance from the shell of the tank, i.e. as a separate cham- ber at a side or at an end of the LNG- fuel tank.
• the tank connection space 26.2 is, preferably, but not necessarily, provided with heat insulation 28.
• the tank connection space 26.2 is formed of one bunkering compartment 30.2, and two LNG- fuel feed com- partments 70.3 and 70.4.
• the tank connection space 26.1 of Figure 2a has a small sized bunkering compartment 30.1 that is surrounded at one side by the LNG- tank and from three sides by the LNG- fuel feed compartments 70.1 and 70.2. Thereby the access to the bunkering compartment 30.1 is from above or from below.
• the tank connection space 26.2 of Figure 2b has a larger sized bunkering compartment 30.2 that is sur- rounded at one side by the LNG- tank 12 and from two sides by the LNG- fuel feed com- partments 70.3 and 70.4 and the fourth side, i.e.
• the end of the bunkering compartment 30.2 opposite the LNG- tank 12 extends to the level of the ends of the LNG- fuel feed compartments, whereby the end wall of the bunkering compartment 30.2 ensures free access (however, through the wall thereof) to the bunkering compartment from the side thereof, too.
• FIG. 3 illustrates a cross section A-A of Figure 2a, and discusses the instru- mentation and equipment needed for filling the LNG- fuel tank 12 with LNG.
• Such equip- ment is provided, in accordance with the present invention, in the bunkering compartment 30.1 of the tank connection space.
• the bunkering compartment 30.1 has a bunkering line 32 for receiving LNG from one of land based bunkering stations, tanker trucks, coastal tankers or bunker barges.
• the bunkering line 32 terminates to a bunkering valve 34, which is used to deliver LNG to a bottom filling line 36 leading from the bunkering com- partment 30.1 to the bottom of the LNG- tank 12 or to a top filling line 38 leading to the LNG sprays 40 in the upper part of the LNG- tank 12.
• the LNG filling lines 36 and 38 lead directly from the bunkering compartment 30.1 through the walls or shells of the tank inside the LNG- tank 12.
• corresponding lines may also be arranged to first leave the bunkering compartment 30.1 through the top wall thereof, and then enter the tank through the top wall thereof, whereby the lines need to be provided with double walls.
• the bunkering valve 34 may also be used to deliver LNG to both filling lines sim- ultaneously.
• the bunkering compartment 30.1 has also a vapour return valve 42 with a vapour return line 44 for collecting vapour from the LNG- tank 12 when filling such.
• the vapour return line 44 takes the vapour for recovery outside the bunkering compartment 30.1 ,
• the bunkering compartment 30.1 has further an emergency pressure relief valve 46, which opens a vent connection along a safety relief line 48 from the top or gas space of the LNG- fuel tank 12 to the vent mast 50 in case pressure in the tank 12 exceeds a predetermined value.
• Instruments 52 for measuring the LNG level L in the LNG- tank 12 are also provided in the bunkering compartment 30.1.
• the bunkering compartment 30.1 further includes ventilation equipment including an air or ventilation inlet line 54 with a first fire damper valve 56 and a ventilation outlet line 58 with a second fire damper valve 60 leading from the bunkering compartment 30.1 to the vent mast 50, and a blower 62, which is positioned in either the ventilation inlet line 54 or the ventilation outlet line 58 for ventilating the bunkering compartment 30.1.
• the first and the second fire damper valves 56 and 60 are in normal operating conditions always open and are automatically closed only if fire is detected in the bunkering compartment 30.1.
• the bunkering compartment 30.1 comprises also a pressure relief valve 64, which connects the interior of the bunkering compartment 30.1 via a pressure relief line 66 to the vent mast 48.
• the pressure relief valve 64 is set to open when the pressure in the bunkering compartment 30.1 exceeds, for instance due to a raised temperature, the maximal allowed bunkering compartment pressure pO.
• the maximal allowed pressure pO in the bunkering compartment 30.1 is usually between 0.1 and 0.5 barg (gauge pres- sure) or 1.1 - 1.5 bar absolute pressure, preferably between 0.2 - 0.4 barg.
• the bunkering compartment 30.1 has a drain 68 at the bottom of the bunkering compartment for collecting any liquid formed or leaked (Glycol/Water in heat exchange circuit/s) in the bunkering compartment 30.1.
• Figure 4 illustrates a cross section B-B of Figure 2a, and discusses the instru- mentation and equipment needed for providing an engine with NG and provided, in ac- cordance with the present invention, in the LNG- fuel feed compartment 70.1 of the tank connection space.
• the LNG- fuel feed compartment has a number of same pieces of equipment than the bunkering compartment, now such are marked with the same refer- ence numerals except for being preceded by‘2’.
• the ventilation of the LNG- fuel feed compartment thus, includes an air or ventilation inlet line 254 with a first fire damper valve 256 and a ventilation outlet line 258 with a second fire damper valve 260 leading from the LNG- fuel feed compartment 70.1 to the vent mast 250, and a blower 262, which is positioned in either the ventilation inlet line 254 or the ventilation outlet line 258 for ventilating the LNG- fuel feed compartment 70.1.
• the first and the second fire damper valves 256 and 260 are in normal operating conditions always open and are automatically closed only if fire is detected in the LNG- fuel feed compartment 70.1.
• the LNG- fuel feed compartment comprises also a pressure relief valve 264, which connects the interior of the LNG- fuel feed compartment via a pressure relief line 266 to the vent mast 250.
• the pressure relief valve 264 is set to open when the pressure in the LNG- fuel feed compartment 70.1 exceeds, for instance due to a raised temperature, the maximal al- lowed LNG- fuel feed compartment pressure pO.
• the maximal allowed pressure pO in the LNG- fuel feed compartment is usually between 0.1 and 0.5 barg (gauge pressure) or 1.1 - 1.5 bar absolute pressure, preferably between 0.2 - 0.4 barg.
• the LNG- fuel feed compartment the TCS has a drain 268 at the bottom of the space for collecting any liquid formed or leaked (Glycol/Water in heat exchange circuit/s) in the LNG- fuel feed compartment.
• Equipment located specifically in the LNG- fuel feed compartment i.e. equipment needed for providing an engine with NG fuel, comprise an LNG outlet line 72 taking liquid LNG from the bottom of the LNG- tank 12.
• LNG is taken via an LNG outlet valve 74 to a main LNG evaporator 76.
• the LNG- fuel is vaporized in the evaporator 76 and continues in a gaseous state to a gas heater 78 from where the heated gaseous NG is taken along fuel feed line 80 and via a main gas valve 82 to an engine.
• a line 84 leads from between the LNG outlet valve 74 and the main LNG evap- orator 76 and via a valve 86 to the top or gas space of the LNG- tank 12 for taking liquid LNG to the tank 12.
• a line 88 introduces vaporized LNG from between the main LNG evaporator 76 and the gas heater 78 via a valve 90 to the gas cavity of the LNG- tank 12. Further, a line 92 takes heated NG from the fuel feed line 80 and via valve 94 to the line
• a boil-off gas (BOG) line 96 leads out of the gas space of the LNG- tank 12 via a boil-off gas valve 98 to a compressor room (not shown) outside the LNG- fuel feed compartment 70.1.
• a gas (BOG) heater 100 may be coupled if needed to the BOG line 96.
• the LNG- fuel feed compartment comprises also a pressure build-up arrange- ment 102, which takes LNG from the LNG outlet line 72 at the bottom of the LNG- tank 12 via a pressure build-up valve 104 to a pressure build-up unit 106, i.e. a heat ex- changer, that vaporizes the LNG.
• the vaporized LNG is taken via a pressure build-up line 108 to the gas cavity of the LNG- tank 12 for raising the pressure therein.
• the recir- culation lines 84, 88 and 92 and the pressure build-up line 108 may be arranged to enter via a single line from the LNG- fuel feed compartment 70.1 to the LNG- tank 12.
• FIG. 5 illustrates schematically a second variation of the LNG- fuel feed com- partment 70.1 of Figure 4.
• the only difference compared to the first variation discussed in Figure 4 is the way LNG is taken from the bottom of the tank 12.
• a cryogenic pump 1 10 is provided in the LNG outlet line 72 upstream of the LNG outlet valve 74.
• the pump 110 replaces the pressure build-up arrangement of Figure 4.
• FIG. 6 illustrates schematically a further development of the bunkering compart- ment 30.1 of Figure 3.
• the bunkering compartment 30.1 is here provided, in addition to the equipment needed for filling the LNG- fuel tank 12 with LNG discussed in Figure 3, with means for arranging an inert atmosphere in the bunker- ing compartment 30.1.
• the ventilation inlet line 54 of the bunkering compartment 30.1 of the tank connection space is provided with a first closing valve 112 in addition to the first fire damper valve 56 and the ventilation outlet line 58 is provided with a second closing valve 114 in addition to the second fire damper valve 60 so that the bunkering compart- ment 30.1 may be closed from outside atmosphere for inerting thereof.
• the bunkering compartment 30.1 further comprises an inlet line 1 16 for introducing inert gas from a gas source 1 18 to the bunkering compartment 30.1 and a gas outlet line 120 for discharging gas from the bunkering compartment 30.1 to the vent mast 50.
• the inert gas inlet line 1 16 is provided with a first pressure regulating valve 122, preferably but not necessarily, outside the bunkering compartment 30.1 for controlling the inert atmosphere in the bun- kering compartment 30.1.
• the gas outlet line 120 is connected via a second pressure regulating valve 124 therein to the vent mast 50.
• the gas outlet line 120 is provided with an oxygen analyser 126 for monitoring the oxygen concentration of the gas discharged from the bunkering compartment 30.1.
• the oxygen analyser 126 may also be located in connection with the bunkering compartment 30.1 upstream of the second pressure reg- ulating valve 124 or the gas outlet line 120.
• the first pressure regulating valve 122 is a pilot operated valve that receives its control signal from the pressure of the bunkering compartment 30.1 such that the first pressure regu- lating valve 122 opens when pressure in the bunkering compartment 30.1 goes below upper limit pressure p1 , i.e. the first pressure regulating valve 122 allows inert gas enter the bunkering compartment 30.1 , when the pressure in the bunkering compartment 30.1 is below p1.
• the second pressure regu- lating valve 124 is also a pilot operated valve that receives its control signal from the pressure of the bunkering compartment 30.1. The second pressure regulating valve 124 opens, i.e. bleeds gas from the bunkering compartment 30.1 to the vent mast 50, when the pressure in the bunkering compartment 30.1 is above a predetermined lower limit pressure p2.
• the first pressure reg- ulation valve 122 receives its control signal from the pressure of the bunkering compart- ment 30.1 such that it is adjusted or instructed to close when an upper pressure limit p1 is reached, in other words, it remains open below pressure of p1.
• the second pressure regulating valve 124 receives its control signal from the pressure of the bunkering com- partment 30.1 such that it is adjusted or instructed to open at a pressure of px and remain open until pressure has reduced to p2, whereby px>p2. Pressures p1 and px may be equal or different, the only thing that matters is that p1 and px are greater than p2.
• the opening of the second pressure regulating valve 124 at pressure of px is used to instruct the first pressure regulating valve 122 to close such that the first pres- sure regulating valve 122 remains closed until the second pressure regulating valve 124 closes at a pressure of p2.
• the closing of the second pressure regulating valve 124 re- turns the control of the first pressure regulating valve 122 to the bunkering compartment pressure, whereby the first pressure regulating valve 122 opens and pressure in the bun- kering compartment 30.1 increases until the second pressure regulating valve 124 re- ceives its control signal from the bunkering compartment pressure at px, opens and takes over the control of the first pressure regulating valve 122 closing it.
• the closing of the first pressure regulating valve 122 at a pressure of p1 is used to instruct the second pressure regulating valve 124 to open, to take over the control and to keep the first pressure regulating valve 122 closed until the second pres- sure regulating valve 124 closes at a pressure p2.
• the control of the first pres- sure regulating valve 122’ is given to the bunkering compartment pressure, so that the first pressure regulating valve 122 opens allowing the pressure in the bunkering compart- ment 30.1 to increase and keeps the second pressure regulating valve 124 closed until pressure of p1 is reached.
• the oxygen concentration has an effect on the functioning of the first and the second pressure regulating valves 122 and 124 as will be discussed later on.
• the ventilation inlet line 54 and the ventilation outlet line 58 are closed by means of the first and second fire damper valves 56 and 60 and the first and the second pressure regulating valves 122 and 124 are activated, i.e. the valves 122 and 124 receive their control signal from at least the pilot pressure of the bunkering compartment.
• the inerting of the bunkering compartment 30.1 may be performed by two basically different ways, i.e. by continuous purging or by using pressurization cycles.
• the first way includes keeping both the first and the second pressure regulating valves 122 and 124 open, i.e. continuously purging the bunkering compartment 30.1 until the oxygen concentration of the gas in the bunkering compartment 30.1 , i.e. upstream of the gas outlet line 120, or of the gas discharged from the bunkering compartment 30.1 downstream of the second pressure regulation valve 124 in the discharge line 120 is, determined by the oxygen analyser 126, reduced below maximum allowable oxygen con- centration.
• the first preferred operation scheme is used such that the activation of the pressure regulating valves 122 and 124 means that as long as the oxygen concen- tration in the bunkering compartment 30.1 , i.e.
• valves 122 and 124 remain open, and only after the maximum allowable oxygen concentration is reached either the first pressure regulation valve 122 or the second pressure regulating valve 124 closes, i.e. after having received control signal from the oxygen analyser 126.
• the second pressure regulating valve 124 closes, too, as soon as the pressure in the bunkering compartment 30.1 is reduced below p2, and in the latter instance, the first pressure regulating valve 122 closes when the pressure in the bunker- ing compartment 30.1 reaches p1.
• the bunkering compart- ment pressure after inerting is p2 and in the latter instance p1.
• the oxygen concentration may, optionally, be followed such that the first or the second pressure reg- ulating valve 122 or 124 is manually (instead of automatic control) closed.
• both valves 122 and 124 are inactivated, i.e. set to a stand-by mode from which they would be re-activated by increase in the oxygen concentration or reduction of pressure in the bunkering compartment.
• the pressure control of the bunkering compartment 30.1 is left for the pressure relief valve 64.
• the second way includes utilizing pressurisation cycles which requires that the operation of the valves are set in a manner different from the first operating scheme.
• the first pressure regulat- ing valve 122 used for introducing inert gas into the bunkering compartment 30.1 opens as the pressure in the bunkering compartment 30.1 is atmospheric pressure p1 and the second pressure regulating valve 124 remains closed until the pressure in the bunkering compartment 30.1 exceeds the predetermined pressure p1 causing opening of the sec- ond pressure regulating valve 124 and, as a function thereof, closing of the first pressure regulating valve122, whereby the pressure is allowed to decrease below the second pre- determined value p2, which causes the closing of the second pressure regulating valve 124 and, as a function thereof, opening of the first pressure regulating valve 122.
• the operation is continued until the oxygen concentration of the gas in the bunkering com- partment 30.1 , i.e. upstream of the gas outlet line 120, or of the gas discharged from the bunkering compartment 30.1 downstream of the second pressure regulation valve 124 in the gas outlet line 120 is, determined by the oxygen analyser 126, reduced below max- imum allowable oxygen concentration, i.e. such an oxygen concentration is reached that combustion of NG is not any more possible irrespective of the concentration of the fuel.
• the desired oxygen concentration is reached at least either the first or the second pressure regulating valve 122 or 124 is closed.
• the pressure in the bunkering compartment 30.1 is either p2 or p1 , respectively, and both valves 122 and 124 may be inactivated, i.e. set to a stand-by mode from which they would be re-activated by increase in the oxygen concentration or reduction of pressure in the bunkering compartment 30.1.
• the pressure control of the bunkering compartment 30.1 is left for the pressure relief valve 64.
• the first pressure regulating valve 122 used for introducing inert gas into the bunkering compart- ment 30.1 opens as the pressure in the bunkering compartment 30.1 is atmospheric pressure and thus below p1 and the second pressure regulating valve 124 remains closed until the pressure in the bunkering compartment 30.1 exceeds the predetermined pressure p1 causing closing of the first pressure regulating valve 122 and, as a function thereof, opening of the second pressure regulating valve 124.
• the first pressure regulat- ing valve 122 remains closed, whereby the bunkering compartment pressure is allowed to decrease below the second predetermined value p2, which causes the closing of the second pressure regulating valve 124 and, as a function thereof, opening of the first pres- sure regulating valve 122.
• the operation is continued until the oxygen concentration of the gas in the bunkering compartment 30.1 , i.e. upstream of the gas outlet line 120, or of the gas discharged from bunkering compartment 30.1 downstream of the second pres- sure regulation valve 124 in the gas outlet line 120 is, determined by the oxygen analyser 126, reduced below maximum allowable oxygen concentration, i.e. such an oxygen con- centration is reached that combustion of NG is not any more possible irrespective of the concentration of the fuel.
• both valves 122 and 124 may be inactivated, i.e. set to a stand-by mode from which they would be re-activated by increase in the oxygen concentration or reduction of pressure in the bunkering compartment 30.1.
• the pressure control of the bunkering compartment 30.1 is left for the pressure relief valve 64.
• the checking of the functionality of the fire damper and the closing valves is performed such that first the fire damper valve 56 or 60 is closed and the closing valve 112 or 114 is opened, and the inlet line 54 or the outlet line 58 leading away from the closing valve 1 12 or 114, i.e. in a direction opposite to the bunkering com- partment 30.1 , is monitored to see if any leak from the bunkering compartment 30.1 may be noticed. If not, the fire damper valve 56 or 60 appears to be in good condition, where- after the closing valve 1 12 or 1 14 is closed and the fire damper valve 56 or 60 opened. Next, again the inlet line 54 or the outlet line 58 leading away from the closing valve 112 or 114, i.e.
• the closing valve 1 12 or 114 is also in good condition, and may be closed. Naturally, if any leakage is detected through any one of the fire damper and closing valves 56, 60, 1 12 or 114, or any other problems in their operation is found out, the malfunctioning valve needs to be replaced or maintained.
• FIG. 7 illustrates schematically a further development of the LNG- fuel feed compartment 70.1 of Figure 4.
• the illustrated further development is the same as dis- cussed above in connection with the bunkering compartment. Now the same inerting equipment are brought to or in connection with the LNG- fuel feed compartment 70.1.
• the LNG- fuel feed compartment 30.1 is here provided, in addition to the equipment needed for filling the LNG- fuel tank 12 with LNG discussed in Figure 3, with means for arranging an inert atmosphere in the LNG- fuel feed compart- ment 70.1.
• the ventilation inlet line 254 of the LNG- fuel feed compartment 70.1 of the tank connection space is provided with a first closing valve 212 in addition to the first fire damper valve 256 and the ventilation outlet line 258 is provided with a second closing valve 214 in addition to the second fire damper valve 260 in so that the LNG- fuel feed compartment 70.1 may be closed from outside atmosphere for inerting thereof.
• the LNG- fuel feed compartment 70.1 further comprises an inlet line 216 for introducing inert gas from a gas source 218 to the LNG- fuel feed compartment 70.1 and a gas outlet line 220 for discharging gas from the LNG- fuel feed compartment 70.1 to the vent mast 250.
• the inert gas inlet line 216 is provided with a first pressure regulating valve 222, preferably but not necessarily, outside the LNG- fuel feed compartment 70.1 for controlling the inert atmosphere in the LNG- fuel feed compartment.
• the gas outlet line 220 is connected via a second pressure regulating valve 224 therein to the vent mast 250.
• the gas outlet line 220 is provided with an oxygen analyser 226 for monitoring the oxygen concentration of the gas discharged from the LNG- fuel feed compartment 70.1.
• the oxygen analyser 226 may also be located in connection with the LNG- fuel feed compartment 70.1 upstream of the second pressure regulating valve 224 or the gas outlet line 220.
• the first pressure regulating valve 222 is a pilot operated valve that receives its control signal from the pressure of the LNG- fuel feed compartment 70.1 such that the first pressure regulating valve 222 opens when pressure in the LNG- fuel feed compartment 70.1 goes below upper limit pressure p1 , i.e. the first pressure regulating valve 222 allows inert gas enter the LNG- fuel feed compartment 70.1 , when the pressure in the LNG- fuel feed compartment 70.1 is below p1.
• the sec- ond pressure regulating valve 224 is also a pilot operated valve that receives its control signal from the pressure of the LNG- fuel feed compartment 70.1.
• the second pressure regulating valve 224 opens, i.e. bleeds gas from the LNG- fuel feed compartment 70.1 to the vent mast 250, when the pressure in the LNG- fuel feed compartment 70.1 is above a predetermined lower limit pressure p2.
• the first pressure reg- ulation valve 222 receives its control signal from the pressure of the LNG- fuel feed com- partment 70.1 such that it is adjusted or instructed to close when an upper pressure limit p1 is reached, in other words, it remains open below pressure of p1.
• the second pressure regulating valve 224 receives its control signal from the pressure of the LNG- fuel feed compartment 70.1 such that it is adjusted or instructed to open at a pressure of px and remain open until pressure has reduced to p2, whereby px>p2. Pressures p1 and px may be equal or different, the only thing that matters is that p1 and px are greater than p2.
• the opening of the second pressure regulating valve 224 at pressure of px is used to instruct the first pressure regulating valve 222 to close such that the first pres- sure regulating valve 222 remains closed until the second pressure regulating valve 224 closes at a pressure of p2.
• the closing of the second pressure regulating valve 224 re- turns the control of the first pressure regulating valve 222 to the LNG- fuel feed compart- ment pressure, whereby the first pressure regulating valve 222 opens and pressure in the LNG- fuel feed compartment 70.1 increases until the second pressure regulating valve 224 receives its control signal from the LNG- fuel feed compartment pressure at px, opens and takes over the control of the first pressure regulating valve 222 closing it.
• the closing of the first pressure regulating valve 222 at a pressure of p1 is used to instruct the second pressure regulating valve 224 to open, to take over the control and to keep the first pressure regulating valve 222 closed until the second pres- sure regulating valve 224 closes at a pressure p2.
• the control of the first pres- sure regulating valve 222’ is given to the LNG- fuel feed compartment pressure, so that the first pressure regulating valve 222 opens allowing the pressure in the LNG- fuel feed compartment 70.1 to increase and keeps the second pressure regulating valve 224 closed until pressure of p1 is reached.
• the pressures p2, p1 or px being used when setting the first and the second pressure regulating valves in operative condition are quite low, however it always applies that p2 ⁇ p1 and p2 ⁇ px.
• the oxygen concentration has an effect on the functioning of the first and the second pressure regulating valves 222 and 224 as will be discussed later on.
• the ventilation inlet line 254 and the ventilation outlet line 258 are closed by means of the first and second closing valves 256 and 260 and the first and the second pressure regulating valves 222 and 224 are activated, i.e. the valves 222 and 224 receive their control signal from at least the pilot pressure of the LNG- fuel feed compartment.
• the inerting of the LNG- fuel feed compartment 70.1 may be performed by two basically different ways, i.e. by continuous purging or by using pressurization cycles.
• the first way includes keeping both the first and the second pressure regulating valves 222 and 224 open, i.e. continuously purging the LNG- fuel feed compartment 70.1 until the oxygen concentration of the gas in the LNG- fuel feed compartment 70.1 , i.e. upstream of the gas outlet line 220, or of the gas discharged from the LNG- fuel feed compartment 70.1 downstream of the second pressure regulation valve 224 in the dis charge line 220 is, determined by the oxygen analyser 226, reduced below maximum allowable oxygen concentration.
• the first preferred operation scheme is used such that the activation of the pressure regulating valves 222 and 224 means that as long as the oxygen concentration in the LNG- fuel feed compartment 70.1 , i.e.
• valves 222 and 224 remain open, and only after the maximum allowable oxygen concentration is reached either the first pressure regulation valve 222 or the sec- ond pressure regulating valve 224 closes, i.e. after having received control signal from the oxygen analyser 226.
• the second pressure regulating valve 224 closes, too, as soon as the pressure in the LNG- fuel feed compartment 70.1 is re- symbolized below p2, and in the latter instance, the first pressure regulating valve 222 closes when the pressure in the LNG- fuel feed compartment 70.1 reaches p1.
• the LNG- fuel feed compartment pressure after inerting is p2 and in the latter instance p1.
• the oxygen concentration may, optionally, be followed such that the first or the second pressure regulating valve 222 or 224 is manually (in place of automatic control) closed.
• both valves 222 and 224 are inactivated, i.e. set to a stand-by mode from which they would be re-activated by increase in the oxygen concen- tration or reduction of pressure in the LNG- fuel feed compartment.
• the pressure control of the LNG- fuel feed compartment 70.1 is left for the pressure relief valve 264.
• the second way includes utilizing pressurisation cycles which requires that the operation of the valves are set in a manner different from the first operating scheme.
• the first pres- sure regulating valve 222 used for introducing inert gas into the LNG- fuel feed compart- ment 70.1 opens as the pressure in the LNG- fuel feed compartment 70.1 is atmospheric pressure p1 and the second pressure regulating valve 224 remains closed until the pres- sure in the LNG- fuel feed compartment 70.1 exceeds the predetermined pressure p1 causing opening of the second pressure regulating valve 224 and, as a function thereof, closing of the first pressure regulating valve 222, whereby the pressure is allowed to decrease below the second predetermined value p2, which causes the closing of the second pressure regulating valve 224 and, as a function thereof, opening of the first pres- sure regulating valve 222.
• the operation is continued until the oxygen concentration of the gas in the LNG- fuel feed compartment 70.1 , i.e. upstream of the gas outlet line 220, or of the gas discharged from the LNG- fuel feed compartment 70.1 downstream of the second pressure regulation valve 224 in the gas outlet line 220 is, determined by the oxygen analyser 226, reduced below maximum allowable oxygen concentration, i.e. such an oxygen concentration is reached that combustion of NG is not any more possible irrespective of the concentration of the fuel.
• the desired oxygen concentration is reached at least either the first or the second pressure regulating valve 222 or 224 is closed.
• the pressure in the LNG- fuel feed compartment 70.1 is either p2 or p1 , respectively, and both valves 222 and 224 may be inactivated, i.e. set to a stand-by mode from which they would be re-activated by increase in the oxygen concentration or reduction of pressure in the LNG- fuel feed compartment 70.1.
• the pressure control of the LNG- fuel feed compartment 70.1 is left for the pressure relief valve 264.
• the first pressure regulating valve 222 used for introducing inert gas into the LNG- fuel feed compartment 70.1 opens as the pressure in the LNG- fuel feed compartment 70.1 is atmospheric pressure and thus below p1 and the second pressure regulating valve 224 remains closed until the pressure in the LNG- fuel feed compartment 70.1 exceeds the predetermined pressure p1 causing closing of the first pressure regulating valve 222 and, as a function thereof, opening of the second pressure regulating valve 2124.
• the first pressure regulating valve 222 remains closed, whereby the LNG- fuel feed compart- ment pressure is allowed to decrease below the second predetermined value p2, which causes the closing of the second pressure regulating valve 224 and, as a function thereof, opening of the first pressure regulating valve 222.
• the operation is continued until the oxygen concentration of the gas in the LNG- fuel feed compartment 70.1 , i.e. upstream of the gas outlet line 220, or of the gas discharged from LNG- fuel feed compartment 70.1 downstream of the second pressure regulation valve 224 in the gas outlet line 220 is, determined by the oxygen analyser 226, reduced below maximum allowable oxygen con- centration, i.e. such an oxygen concentration is reached that combustion of NG is not any more possible irrespective of the concentration of the fuel.
• both valves 222 and 224 may be inactivated, i.e. set to a stand-by mode from which they would be re-activated by increase in the oxygen concen- tration or reduction of pressure in the LNG- fuel feed compartment 70.1.
• the pres- sure control of the LNG- fuel feed compartment 70.1 is left for the pressure relief valve 64.
• the checking of the functionality of the fire damper and the closing valves is performed such that first the fire damper valve 256 or 260 is closed and the closing valve 212 or 214 is opened, and the inlet line 254 or the outlet line 258 leading away from the closing valve 212 or 214, i.e. in a direction opposite to the LNG- fuel feed compartment 70.1 , is monitored to see if any leak from the LNG- fuel feed compartment 70.1 may be noticed. If not, the fire damper valve 256 or 260 appears to be in good condition, whereafter the closing valve 212 or 214 is closed and the fire damper valve 256 or 260 opened. Next, again the inlet line 254 or the outlet line 258 leading away from the closing valve 212 or 214, i.e.
• the closing valve 212 or 214 is also in good condition, and may be closed. Naturally, if any leakage is detected through any one of the fire damper and closing valves 256, 260, 212 or 214, or any other problems in their operation is found out, the malfunctioning valve needs to be replaced or maintained.
• the inert gas used for inerting the bunkering or LNG- fuel feed compartments is preferably nitrogen, though also argon may be used.
• the inert gas source 118/218 is either a generator separating the inert gas from air, or a pressurized container carrying the inert gas. In case the generator is used, it is preferable to store the inert gas in a buffer tank for later use.
• pressures p1 , p2, px or pO do not necessarily refer to the same pressure values in each and every example, but they may change.
• p2 ⁇ p1 ⁇ p0 and p2 ⁇ px ⁇ p0 in each exemplary embodiment, running scheme or variation.
• the first and the second pressure regulation valves 122/222 and 124/224 may be positioned either inside or outside the bunkering or the LNG- fuel feed compartment.
• the equipment for filling the LNG- fuel tank with LNG in the bunkering compartment as well as the equipment needed for providing an engine with NG in the LNG- fuel feed compartment comprises such pipelines, valves and other instrumentation that has not been shown in Figures 3 - 7.
• One piece of such equipment is thermal valves and pipelines related thereto for connecting any such parts of the vari- ous lines to the vent mast that warming of the LNG or gaseous NG may increase pressure in.
• all connections and pipelines relating to heating or evaporating of the LNG and heating of NG, i.e. various water or water/glycol lines have been left out.

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