Method and apparatus for cooling high temperature components in a gas turbine

A combustion turbine system comprising:

• a) A compressor for compressing air from an air source and delivering the compressed air to a compressor output;
• b) A combustion for igniting a fuel, received from a fuel source, in a mixture of compressed air received from the compressor output to form a working gas which is communicated to an output section of the combustion:
• c) A transition member coupled at an upstream end to the output section of the combustion for receiving and directing the working gas to a downstream end of the transition member:
• d) A turbine connected at one end to the downstream end of the transition section, for receiving and expanding the working gas:
• e) A compressed air conduit connected at one point to the compressor for bleeding off at least a portion of the air compressed in the compressor, and at a second point to a cooling conduit that is in flow communication with a cooling circuit in at least one of said combustion, transition member and turbine for cooling a component thereof;
• f) A nitrogen source;
• g) A nitrogen conduit connected at one point to the nitrogen source and at a second point to the cooling conduit;
• and
• h) A device for metering the volume of air flow through said compressed air conduit to said cooling conduit and the volume of nitrogen flow through said nitrogen conduit to said cooling conduit for controlling the proportion of nitrogen to air content of a cooling gas delivered to cool said component.