PURPOSE: To obtain efficiently a gas turbine fuel which does not evolve CO2 during combustion by reforming liquefied natural gas successively in a reformer and by the shift reaction, separating CO2 from the reformed gas, and liquefying the CO2 by the cold heat of the liquefied natural gas.

CONSTITUTION: After the recovery of the cold heat of liquefied natural gas (hereinafter referred to an LNG) in cold-heat-recovery heat-exchangers 1 and 2, the LNG is gasified in an LNG vaporizer 3 and fed to a reformer 4. Steam is fed to the reformer 4 at the same time to reform CH4 in the feed gas to H2 and CO. Then, the reformed gas is introduced into a high-temperature CO shift reactor 5 and a low-temperature shift reactor 6 to reform the CO through the shift reaction with steam to H2 and CO2. Thereafter, the reformed gas is fed into PSA11 for CO2 absorption to separate and remove the CO2 which is then liquefied in a CO2 liquefier 13 making use of the cold heat of the LNG. On the other hand, the reformed gas, from which CO2 has been separated, is used as a fuel in a gas turbine 15.