A pump-free pressure boosting system for LNG fuel gas supply system

Abstract

This study proposed a concept of a pump-free type system for the LNG fuel gas supply for large-size carriers. Fuel LNG was loaded in one of IMO type ‘C’ tank insulated by R-PUF. The stored LNG fuel was supplied into two heaters which vaporized and boosted LNG up to the target condition of -120 ℃ and 6.5 bara, replacing the role of pumps in conventional systems. The two heaters were adapted to continuous supply the fuel gas in a way that one was vaporizing while the other was loaded with LNG. Process dynamic simulation indicated that the pressure of the LNG storage tank was significantly increased when it was connected with the heaters for LNG filling, allowing the vapor flow into the LNG storage tank and ultimately giving rise to an increase in the pressure of the LNG storage tanks. Long-term dynamic process simulation, however, demonstrated that the increase in the tank pressure would be so slow that the new concept might guarantee steady and slow supply of fuel gas to the engines.