Patent ID: 7472540

Claim:
A gas turbine system comprising: a control device for adjusting a fuel supply in a gas turbine system having a plurality of burner stages operated in parallel in which a plurality of fuel control valves are allocated to the burner stages and a regulator is allocated to the fuel control valves to compensate for variations in a fuel composition, the control device including an analyzer for analyzing the fuel composition, a computing unit for calculating a current Wobbe index of the fuel composition based on the analysis, and an updating unit for adjusting the regulator and the fuel control valves based on the calculated current Wobbe index to keep the fuel supply split between the burner stages at a constant target value; a fuel line through which a fuel flows, including a branching point on the fuel line for branching off a part of the fuel and for introducing the branched off fuel into a branch line as an analysis sample flow; and the analyzer positioned to receive the analysis sample flow, wherein a distance between the branching point and the fuel control valves is sufficiently elongated to allow: the analyzer to fully analyze the fuel composition of the sample flow, the computing unit to fully calculate the current Wobbe index, and the updating unit to fully adjust the regulator and the fuel control valves before the fuel reaches the fuel control valves.