Possible effects of coal chlorine on furnace wall fireside corrosion in utility boilers

Fireside corrosion represents a prominent threat to the integrity of furnace wall tubing in many pulverized fuel-fired boilers world-wide. This paper is concerned with establishing the factual basis for the existence of a limitation on chlorine content in coal specifications used by utilities. This limitation currently is based primarily on information reported by U.K. utilities. A sound understanding of the effects of chlorine-if any-on fireside corrosion in utility boilers would provide a rational basis for utility cost-benefit decisions. Such an understanding also could lead to a basis for increasing the interest of utilities in high chlorine coals, which are currently underutilized. The paper summarizes the results of (1) a review of the many years of experience that U.K. utilities have had with high-chlorine coals, (2) a test program in the U.K., employing novel corrosion probe technology in a model test facility, to derive a relationship for use in coal quality evaluation tools and (3) an overview of lessons learned from the U.K. experience that should allow utilities to develop a more informed position when considering use of high-chlorinecoal.