Gas turbine power augmentation injection system and related method

A method of augmenting power in a gas turbine plant that includes a compressor, at least one combustor, a turbine component and an output shaft, comprising:

• a) supplying air and water to a heat recovery boiler for heat exchange with exhaust gas from the turbine component;
• b) providing a turbine controller that controls supply of air, steam or a mixture of air and steam to the combustor;
• c) storing data in the turbine controller including viscosity and density of air, steam and equations for determining properties of any mixture of air and steam;
• d) measuring a differential pressure of the air, steam or mixture of air and steam across a metering tube located upstream of the combustor;
• e) determining instantaneously the mass flow rate of the air, steam or mixture of air and steam as a function of said differential pressure and desired power output;
• and
• d) supplying the air, steam or mixture of air and steam to the combustor at the flow rate determined in step e);
• wherein step f) is carried out with a control valve downstream of the metering tube, said control valve operatively connected to said turbine controller.

A land based gas turbine plant comprising a compressor, a turbine component, and a combustor between said compressor and said turbine component;

• a heat recovery boiler arranged to receive exhaust gas from the turbine component;
• means for injecting air, steam, or a mixture of air and steam into the combustor;
• a metering tube and differential pressure measurement device for obtaining differential pressure of the air, steam or mixture of air and steam across the metering tube;
• and means for substantially instantaneously calculating mass flow rate of the air, steam or mixture of air and steam.