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Start-up duration is important parameter in gas turbine process but the equsetion now what is the best fast or slow ? In old system fast start-up approximittly 6 minits but in
[new like G.E control systems it is be 11mints or 12 minits
The slower start-up and acceleration provides the following benefits:

1) Differential expansion between the casing and rotor is reduced which in turn reduces the chance of damaging the turbine bucket tips during start-up transients.

2) The peak exhaust temperatures during the start sequence is reduced which in turn reduced the low cycle fatigue thermal and mechanical stresses on the combustion hardware.

3) Arch-binding and temperature gradients within the GT compressor are reduced which in turn reduces the chance of a heavy compressor rub.

4) The unit is less likely to experience P2 pressure or combustor flame-out problems.