Gas turbine with water injection

Abstract

A gas turbine comprises a compressor for compressing a gas supplied therein and discharging the compressed gas, a combustor in which the discharged gas from the compressor and a fuel are combusted, a turbine to be driven by a combustion gas from the combustor, and a water injection unit which injects water into the gas to be supplied to the compressor, thereby lowering the temperature of the gas to be introduced into the compressor to a temperature lower than the atmospheric temperature, and causing water droplets having been injected in the gas and within the compressor to be vaporized while flowing down therein, wherein the quantity of water spray injection is controlled while monitoring operational conditions of the gas turbine.

1. A gas turbine having a compressor for compressing air supplied thereto and discharging the compressed air, a combustor for combusting the compressed air from said compressor and a fuel and a gas turbine to be driven by a combustion gas from said combustor, comprising:
 an injection unit, arranged within an intake air duct at an upstream side of said compressor and constructed so that water droplets are sprayed into the air to be supplied to the compressor to decrease the temperature of the air to be supplied into said compressor to a temperature lower than an atmospheric temperature and the sprayed water droplets introduced into said compressor with the air having been decreased in temperature are evaporated during passage through said compressor;  
 a NOx concentration detection unit for detecting NOx concentration in said combustion gas;  
 a pressure variation detecting unit for detecting pressure variation in said combustor; and  
 a controlling unit for controlling a quantity of spray of said water droplets so as to suppress the NOx concentration and the pressure variation in said combustor to be in allowable value ranges, respectively.  
 
     
     
       2. A gas turbine according to  claim 1 , wherein said controlling unit increases the quantity of spray of said water droplets when the NOx concentration detected by said NOx concentration detection unit reaches a prescribed value or more and decreases the quantity of spray of said water droplets when the pressure variation in said combustor, detected by said pressure variation detection unit reaches a prescribed value or more.