Gas turbine inlet temperature suppression during under frequency events and related method

Abstract

A method is provided for augmenting power output in a gas turbine electrical power-generating plant including a multistage compressor, a combustor and a multistage turbine component, during events when grid frequency drops below a predetermined target frequency. The method is carried out by a) providing a supply of liquified air arranged to permit selective addition of liquified air to an ambient air inlet to the compressor; and b) flowing controlled amounts of the liquified air into the ambient air inlet during such events.

1 . A method of augmenting power output in a gas turbine electrical power-generating plant comprising a multistage compressor, a combustor and a multistage turbine component, during events when grid, or gas turbine frequency, drops below a predetermined target frequency, or gas turbine load is anticipated to transiently exceed capability, the method comprising:
 a) providing a supply of liquified air arranged to permit selective addition of liquified air to an ambient air inlet to the compressor; and   b) flowing controlled amounts of the liquified air into the ambient air inlet during said events.   
   
   
       2 . The method of  claim 1  including providing at least one control valve in a conduit supplying the liquified air to said ambient air inlet. 
   
   
       3 . The method of  claim 2  wherein step (b) comprises injecting liquified air through plural nozzles located proximate said ambient air inlet of said compressor. 
   
   
       4 . The method of  claim 3  wherein step (b) further comprises mounting said nozzles to a manifold and locating said manifold within a plenum adjacent said ambient air inlet. 
   
   
       5 . The method of  claim 1  wherein step (b) is carried out as a function of grid frequency. 
   
   
       6 . The method of  claim 1  wherein step (b) is carried out as a function of compressor air inlet temperature and turbine power output. 
   
   
       7 . The method of  claim 1  wherein step (b) is carried out to provide a minimum amount of liquified air to maintain a required power output at predetermined frequency levels. 
   
   
       8 . A gas turbine electric power generating plant comprising:
 a multi-stage compressor having an ambient air inlet;   a multi-stage turbine component;   a combustor arranged to receive compressed air from the compressor and to supply gaseous combustion products to the multi-stage turbine component; and   a source of liquified air arranged to supply liquified air to said ambient air inlet of the compressor.   
   
   
       9 . The gas turbine electric power generating plant of  claim 8  comprising a liquified air injection manifold with one or more injection nozzles located proximate said ambient air inlet. 
   
   
       10 . The gas turbine electric power generating plant of  claim 9  and further comprising a conduit arranged between said source of liquified air and said ambient air inlet, with a control valve located in said conduit, upstream of said manifold. 
   
   
       11 . The gas turbine electric power generating plant of  claim 10  wherein said manifold is located within a plenum adjacent said ambient air inlet.