High temperature corrosion during use of chlorine

Abstract

The goal of this project is to characterize the role of chlorine in coal on the high temperature corrosion processes which can occur in coal combustion and conversion processes. The experience include laboratory tests performed in well-controlled high temperature environments and field tests in industrial coal fired boilers. Evaluation of samples of boiler tubes which have been recovered from boilers which used both high and low chlorine coals does not indicate that the higher chlorine levels are associated with accelerated corrosion of either water wall tubes or superheater tubes in pulverized coal boilers. Laboratory testing of metal coupons in combustion gas environments produced from low sulfur, high chlorine coal IBC-109 and high sulfur-low chlorine coal IBC-101 has been performed at 700 and 800{degree}C. Initial results indicate that more overall corrosion is produced in the high sulfur environment than in the high chlorine environment. Internal attack in the highly alloyed metals alloy 800 and 310 stainless steel is accelerated by the presence of chlorine in the environment, but the level of chlorine required to produce this attack has not yet been determined. Further testing at other temperatures and gas compositions is in progress.