High temperature corrosion of boiler steels in hydrochloric atmosphere under oil shale ashes

High temperature corrosion in power plants is a main breakdown criterion in boiler applications. This study is focused on the high-temperature corrosion resistance of several boiler steels used in Estonian power plants, which were experimentally tested in gaseous hydrochloric environment combined with Estonian oil shale ashes in a high temperature corrosion test up to 600 °C. Scanning electron microscopy supported by energy dispersive X-ray spectroscopy was used to reveal different corrosion mechanisms. Results indicate a strong dependence of the boiler steel corrosion to the present anions in the oil shale ash and their removal in the boiler.