Patent ID: 7950238

Claim:
A method for performing a transfer from gas fuel operation to liquid fuel operation for a gas turbine, including a compressor; combustors; a turbine; a turbine control system with a controller; and a gas fuel delivery system and a liquid fuel delivery system arranged to deliver fuel to the combustors wherein during the transfer from gas fuel operation to liquid fuel operation the gas fuel delivery system is purged of air with a liquid fuel prefill flow; and further wherein the prefill liquid fuel flow reaching the combustors is not recognized by the controller in fuel demand signals for the gas turbine control and is termed uncontrolled liquid fuel, the method comprising: initiating by a controller of a predetermined liquid fuel prefill flow rate through the liquid fuel system for filling of liquid fuel lines with liquid fuel; sensing by the controller of an onset of uncontrolled liquid fuel flow to combustor nozzles; and initiating by the controller of a transfer from gas fuel operation to liquid fuel operation when the flow of uncontrolled liquid fuel at the combustor nozzles is sensed.