Fuel gas supply system and method of an LNG carrier
View Patent ↗A fuel gas supply system of a vessel, such as an LNG carrier, is provided for supplying fuel gas to a high-pressure gas injection engine of an LNG carrier, wherein LNG is extracted from an LNG storage tank of the LNG carrier, compressed at a high pressure, gasified, and then supplied to the high-pressure gas injection engine. In one embodiment, the system is operated to supply fuel to an MEGI engine.
1. A fuel gas supply system of an LNG transportation vessel, the system comprising:
an LNG storage tank configured to store LNG;
a high-pressure gas injection of the LNG vessel;
a fuel gas supply line connected from the LNG storage tank to the high-pressure gas injection engine;
a first pump device configured to compress the LNG stored in the LNG storage tank and communicate the compressed LNG downstream along the fuel gas supply line;
a second pump device in fluid communication with the first pump device to receive the compressed LNG, the second pump device including a high pressure pump installed outside of the LNG storage tank along the fuel gas supply line, the second pump device configured to compress LNG compressed by the first pump, to a high-pressure of 200 to 300 bar, and supply the compressed LNG toward the engine;
a gasifying device installed downstream of the second pump device along the fuel gas supply line and configured to gasify the compressed LNG: and
a discharge device configured to discharge from the LNG storage tank, boil-off gas generated in the LNG storage tank.
2. The fuel gas supply system according to claim 1 wherein the gasifying means includes a heater.
3. A method for supplying fuel gas to a high-pressure gas injection engine of an LNG transportation vessel, the method comprising:
compressing LNG stored in an LNG storage tank of the LNG carrier by a first pump and communicating the compressed LNG along a fuel supply line to a second pump:
compressing the compressed LNG by the second pump to meet the pressure requirements of the high-pressure gas injection engine of 200-300 bar, the second pump being a high pressure pump and installed outside of the LNG storage tank:
gasifying the compressed LNG;
supplying the gasified LNG to the high-pressure gas injection engine; and
discharging from the LNG storage tank, boil-off gas generated in the LNG storage tank.
4. The method according to claim 3 wherein gasifying the compressed LNG includes heating the compressed LNG.