Lime kiln preheaters are used to “preheat” the limestone prior to the limestone being fed into the kiln. Hot kiln exit gases that might otherwise be exhausted to the environment are used to heat the limestone. This improves operating efficiency and reduces operating costs.
Lime preheater floors are very abrasive service environments. Limestone is preheated and pushed along the floor by hydraulic rams. This action is extremely abrasive, and wear on the refractory floor is common. The use of high-wear-resistant refractories is a necessity. HarbisonWalker International offers a number of products containing silicon carbide and alumina-zirconia-silica (AZS), such as HARBIDE, THOR® AZS, and THOR® AZSP. Our THOR® product line offers superior wear resistance in a variety of application methods. THOR® AZS CASTABLE and THOR® AZSP PLUS both offer outstanding wear resistance for preheater floors.
The limestone leaves the preheater and enters the kiln through the transfer chute. Abrasion and buildup are the main concerns within this area. Limestone continually falls through the transfer chute, where it can erode refractories easily unless the right refractories are installed in this area. HWI offers abrasion-resistant products such as THOR® AZS, THOR® 60, and VERSAFLOW® 80 C PLUS, which are all outstanding products for this application.
The bullnose is a general term that refers to a corner or edge. In preheaters, the corner connects the flat surface of the ceiling to the vertical wall of the internal chamber of the preheater. This area is prone to failure from abrasion due to dust-laden air and buildup, causing air and material-flow restrictions. HWI’s THOR® 30 products contain silicon carbide and offers a high degree of wear and buildup resistance in an economical package. THOR® AZS products offer our highest degree of wear and buildup resistance through the use of both silicon carbide and zirconia. The result is an outstanding product that delivers protection in the severest of service environments.
The throat is the top portion of the transfer chute in the preheater floor. Again, this is an area of high abrasion, and refractory choices must take this into consideration. THOR® AZS, THOR® 60, and VERSAFLOW® 80 C PLUS products offer the abrasion-resistant properties ideal for this environment.