Effect of Heavy Fuel Impurities on Hot Corrosion of Inconel ۶۱۷

The use of heavy fuels containing impurities such as sulfur and vanadium can lead to the destruction of components gas turbine, exposed to combustion environments at high temperature, through hot corrosion. In this study, the effect of sulfur, vanadium, potassium, calcium and lead in heavy fuel oil on the hot corrosion behavior of Inconel ۶۱۷ alloy were investigated. For this purpose, hot corrosion experiments were carried out in the presence of various corrosive compounds including ۶۰%Na۲SO۴+ ۴۰%V۲O۵, ۲%K۲SO۴+ ۵۸%Na۲SO۴+۴۰%V۲O۵, ۱% CaCl۲+ ۲% K۲SO۴+ ۵۷%Na۲SO۴+۴۰%V۲O۵ and ۰.۲% PbCl۲+ ۱% CaCl۲+ ۲% K۲SO۴+ ۵۶.۸%Na۲SO۴+۴۰%V۲O۵ salts at two temperatures of ۷۰۰ °C and ۱۰۰۰ °C for ۸, ۱۶, ۲۴, ۳۲ and ۴۰ hours. The exposed samples were investigated with measurement of weight changes, SEM, EDS and XRD analysis. The results showed that the impurities of potassium, calcium and lead did not have any remarkable effect on the hot corrosion of inconel ۶۱۷. It was also observed that the weight of the specimens increased with increasing hot corrosion time at testing temperature of ۷۰۰ °C. However, a decrease in the weight of specimens was observed after ۸ h hot corrosion at ۱۰۰۰ °C that was due to severe destruction of the surface. The cross-sectional images of the samples corroded at ۷۰۰ °C indicated that there were two layers containing chromium oxide and salt compounds. Nevertheless, the cross-sectional analysis of samples corroded at ۱۰۰۰ °C indicated that there were porous and non-continuous oxide scales on the surface. X-ray diffraction analysis of corrosion products, formed on the corroded specimens at ۱۰۰۰ °C, showed the presence nickel oxide (NiO), chromium oxide (Cr۲O۳), nickel sulfide (NiS), chromium sulfate (Cr۲(SO۴)۲), and sodium chromium oxide (Na۲CrO۴).

Keywords:

Heavy fuel impurities , Hot corrosion , Inconel ۶۱۷ , ناخالصی سوخت سنگین , خوردگی داغ , اینکونل ۶۱۷