Anti-icing system at gas turbine compressor bell-mouth and Inlet Guide Vane (IGV)

Abstract

Anti-icing system is generally used in order to prevent ice formation at gas turbine compressor bell-mouth and inlet guide vanes (IGV) in cold climates, which is caused by air pressure drop and velocity rise and consequent mechanical damage and performance deterioration. Ice formation at the compressor bell-mouth and on the inlet guide vanes is depended on variant parameters including: ambient air temperature, relative humidity of the environment, air velocity at compressor bell-mouth and IGV and metal surface temperature of ice formation location. In two frequent conditions ice may be formed; 1-water droplet existence in liquid or solid phase and in the shape of snow, rain and other precipitations. 2-Existence of vapor condensation in inlet air way that is because of temperature depression and velocity rise. Anti-Icing system by which extracting of hot gas from mid/last-stage of compressor (this method is the most popular methods for anti-icing system), increase inlet air temperature till inlet air in bell-mouth and IGV location gets far from ice forming condition. Extraction of air from compressor is caused performance degrading of gas turbine approximately 2∼5% in power and 1∼2% in efficiency depend on extracted flow rate. So accurate determination of operation limit of Anti-Icing system has great effect on gas turbine performance and its fuel consumption