Pre-fired, refractory block slag dams for wet bottom furnace floors

Slagging (wet bottom), Utility boilers count on a refractory coating over the furnace floor tube structure for protection from corrosion damage from both the harsh, hot gas atmosphere from the burning fuel and the acidic, coal slag. To protect and extend the life of this protective refractory coating, the boiler original equipment manufacturers (OEMs) utilized a water-cooled "Monkey Ring" or slag "Chill Ring" (typically a 6"-8" high ring of small diameter tubes, see Sketch #1, below) surrounding the slag tap locations on most wet bottom furnace floors (both Utility and package boilers). The old water-cooled tube ring was such a high maintenance item, however, that it's use has been discontinued in all but the most extreme environments throughout both Utility and Industrial applications. Where the use of the ring was discontinued, there has been a corresponding shortening of life on the protective floor refractory coatings (high maintenance cost), further aggravated by recent OSHA restrictions limiting the use of chrome oxide refractory materials in these types of boilers. This paper describes the developmental process and the final resultant product (a non-watercooled, slag dam made from pre-fired refractory shapes), undertaken by the inventors. Derived operational benefits and a Concept II project, with NOx Title IV & Title I significance (which is currently underway) will also be detailed.