Methods and apparatus for a combustion turbine fuel recirculation system and nitrogen purge system

A method of operating a dual-fuel system, said method comprising:

• shifting from a liquid fuel mode of operation to a gas fuel mode of operation comprising:
• removing liquid fuel from at least a portion of the dual-fuel system using a gravity drain process, such that substantially all of the liquid is removed from the at least a portion of the dual-fuel system;
• channeling nitrogen into at least a portion of the dual-fuel system to facilitate removing air and residual liquid fuel from at least a portion of the dual-fuel system;
• removing air and nitrogen from at least a portion of the dual-fuel system during a liquid fuel refilling process using a venting process, such that at least a header of the dual-fuel system is substantially refilled with the liquid fuel removed from the at least a portion of the dual-fuel system and is substantially evacuated of air and nitrogen;
• removing air from at least a portion of the refilled liquid fuel system using a venting process;
• and
• recirculating liquid fuel from the header through at least a portion of the dual-fuel system, to facilitate removing heat from at least a portion of the dual-fuel system such that a formation of carbonaceous precipitate particulates within the dual-fuel system is mitigated.