High Temperature Corrosion Behavior of DS GTD-111 in Oxidizing and Sulfidizing Environments

摘要

Recent advances in coal combustion have made coal a cleaner,more viable source for power generation. Integrated GasificationCombined Cycle (IGCC) plants pair conventional steam turbinesand coal gas turbines. The overall efficiency of each system islargely dependent on the maximum operating temperature of thesystem, which is limited by the available materials. Superalloyshave long been used as a turbine material due to their hightemperature strength and general resistance to oxidation.Superalloy GTD-111 DS is currently being used as components insteam turbine engine such as turbine blades and discs and is nowbeing introduced to the syngas environment, which consists of H2,CO, CH4, and H2S in addition to H2O. H2S is highly corrosiveand complicates the corrosion process. The high temperaturecorrosion behavior of a directionally solidified superalloy, GTD-111 DS has been studied using thermogravimtric analysis coupledwith metallographic studies. Parabolic oxidation behavior wasobserved for test environments including dry and wet air.Simulated syngas environments show aggressive sulfidization thatleads to massive sample damage. In the case of wet syngasenvironments, a protective oxide layer was observed which seemto increase the samples ability to resist further corrosion.