A Fuel Gas Supply System of Liquefied Natural Gas and Method for Refueling Liquefied Natural Gas

摘要

The present invention relates to an LNG supply system and an LNG refueling method. The LNG supply system of the present invention comprises an LNG storage tank, which stores LNG supplied to an engine; a pump unit, which compresses LNG discharged from the LNG storage tank; a heat exchanger, which heats LNG compressed by the pump unit and supplies the LNG to the engine; and LNG refueling equipment, which is connected to the LNG storage tank and is combined to a LNG refueling tank. The LNG refueling equipment is arranged in a vent line connected to the upper part of the LNG storage tank. The LNG refueling equipment includes a pressure control valve, which controls inner pressure of the LNG storage tank; and an LNG refueling valve unit equipped in an LNG refueling line unit, which is combined to the LNG refueling tank in one end and is connected to the upper and lower parts of the LNG storage tank in the other end. According to the present invention, the LNG storage tank has the LNG refueling equipment, which lowers inner pressure of the LNG storage tank while LNG is being refueled, using a pressure control valve connected to the upper part of the LNG storage tank and a second LNG refueling valve, and which prevents LNG from being automatically discharged while LNG is being refueled, using an outlet valve connected to the lower part of the LNG storage tank. Therefore, pressure difference between the LNG refueling tank and the LNG storage tank can be maintained while LNG is being refueled, and LNG can be easily refueled into the LNG storage tank.