# US 8,783,041 B2 · LNG transport vessel and method for storing and managing excess boil off gas thereon > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,783,041 B2 - Document ID: US8783041B2 - Status: Granted - Kind: B2 - Application number: 12/797,092 - Filed: 2010-06-09 - Published: 2011-12-15 - Granted: 2014-07-22 - Earliest claimed: 2010-06-09 - Assignees: Chevron U.S.A. Inc. - Applicants: John Hartono; Paul Martella - Inventors: John Hartono; Paul Martella - Web page: https://patentgrep.com/patent/US8783041B2 ## CPC - F01K 13/00: General layout or general methods of operation of complete plants - B63J 99/00: Subject matter not provided for in other groups of this subclass - F23K 5/002: {Gaseous fuel} - B63B 17/0027: {Tanks for fuel or the like (constructional features of bunkers B63B11/04); Accessories therefor, e.g. tank filler caps (fuel tanks for vehicles in general B60K15/03; cargo tanks B63B25/08; cleaning of tanks B63B57/00; handling of liquids for use in power plants B63H21/38)} - B63B 25/16: heat-insulated (insulating panelling B63B3/68; heating or cooling B63J) - B63H 21/02: the vessels being steam-driven (B63H21/18 takes precedence) - B63H 21/12: the vessels being motor-driven (B63H21/175, B63H21/18 take precedence; {cooling circuits with liquid-to-liquid heat-exchange relative to marine vessels F01P3/207}) - B63J 2099/003: {of cargo oil or fuel, or of boil-off gases, e.g. for propulsive purposes} - F23K 2400/20: Supply line arrangements - Y02T 70/50: Measures to reduce greenhouse gas emissions related to the propulsion system - F01K: STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D) - B63J: AUXILIARIES ON VESSELS - F23K: FEEDING FUEL TO COMBUSTION APPARATUS (fuel feeders specially adapted for fluidised bed combustion apparatus F23C10/22) - B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06) - B63H: MARINE PROPULSION OR STEERING (propulsion of air-cushion vehicles B60V1/14; specially adapted for submarines, other than nuclear propulsion, B63G; specially adapted for torpedoes F42B19/00) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A liquefied natural gas (LNG) transport vessel for transporting liquefied natural gas (LNG) is disclosed which is capable of storing excess boil off gas BOG until needed for combustion in one or more combustion apparatus on the vessel. A method for managing the delivery of the BOG to the combustion apparatus is also described. The LNG vessel includes at least one insulated LNG storage tank which stores LNG. A first stage LNG receiver receives and stores BOG from the at least one LNG storage tank. A second stage or high pressure BOG storage tank receives compressed BOG from the receiver and stores the BOG as needed for combustion by one or more combustion apparatus of the vessel. A pressure regulator allows BOG gas to be delivered to the combustion apparatus if there is sufficient pressure in the high pressure storage tank to passively deliver the BOG at a predetermined delivery pressure. If the pressure in the high pressure BOG storage tank is insufficient to passively delivery the BOG to combustion apparatus, then a combustion apparatus compressor may be used to actively increase the pressure in BOG such that the BOG is delivered at the necessary delivery pressure. If there is still insufficient BOG in the high pressure BOG storage tank, then it may be necessary to supply supplemental auxiliary fuel to meet the needs of the combustion apparatus. ## Claims ### Claim 1 A method for combusting boil off gas (BOG) on a liquefied natural gas (LNG) transport vessel, the method comprising the steps of: storing LNG in at least one insulated LNG storage tank on a LNG transport vessel; capturing evaporated BOG from the at least one LNG storage tank and compressing and storing the BOG in a high pressure BOG storage tank; delivering the BOG at a calculated delivery pressure to a first combustion apparatus where the BOG is combusted; wherein when the pressure of the BOG in the high pressure BOG storage tank is insufficient to passively deliver the BOG to the first combustion apparatus at the calculated delivery pressure, then BOG from the high pressure BOG storage tank is compressed downstream from the high pressure BOG storage tank such that the BOG is delivered at the calculated delivery pressure. ### Claim 2 (depends on 1) The method of claim 1 wherein: when the pressure of the BOG in the high pressure BOG storage tank is sufficiently high, then the BOG is delivered to the first combustion apparatus through a passive pressure regulator without need to further compress the BOG from the high pressure BOG storage tank. ### Claim 3 (depends on 1) The method of claim 1 further comprising: delivering an auxiliary fuel to the first combustion apparatus. ### Claim 4 (depends on 1) The method of claim 1 wherein: the first combustion apparatus includes a steam boiler for producing steam to drive a steam turbine. ### Claim 5 (depends on 1) The method of claim 1 wherein: the first combustion apparatus includes a dual fuel diesel engine. ### Claim 6 (depends on 1) The method of claim 1 wherein: the first combustion apparatus includes a gas turbine. ### Claim 7 (depends on 1) The method of claim 1 wherein: the BOG is captured from the at least one LNG storage tank and is compressed and stored in a first stage gas storage tank; and the BOG from the first stage gas storage tank is further compressed and stored in a second stage storage tank which serves as the high pressure BOG storage tank.