A process to increase capacity of LNG plants and minimize fuel gas production.
LNG from the main cryogenic heat exchanger at –140°C, 40 bar is expanded in T1 turbine to produce electric power. It is mixed with liquefied fuel gas recycle before entering the LNG flash drum V1 at 1.2 bars. The LNG is pumped to storage tank through P1.
Cold flash gas is reheated to –30°C and compressed to 30 bar, thus producing fuel gas for gas turbines in K1. Part of the fuel gas is further compressed to 40 bars in K2. A portion of this stream is cooled to –80ºC in E1, expanded to 8 bars at 130ºC in T2. It is then reheated to 30ºC and sent to the fuel gas compressor as a side stream. The second stream portion is liquefied and subcooled in E1 down to –155ºC.
Economics: Additional LNG production investment of about $60/tpy for additional LNG.