Earlier the set point used to maintain between 90 oc to 110 oc , Can any one explain how the variation in gas composition affecting the GT inlet fuel gas temperature setpoint. The wobbe index used to maintain around 1150 n/d but now around 1205 n/d. we contacted gas supplier is there any change in gas composition , they said there is no change..How it affeting the gas fuel temperature can any one explain to me.

 

It would seem you are using an on-site gas chromatograph to measure some gas constituents?

Are you certain of the calibration of the instrument?

If there is doubt about the gas supply, then it would seem prudent to have a gas sample tested by an independent third party. That would also be a good check on the calibration of the on-site instrument.