Parallel-flow regenerative lime kilns and processes for burning and cooling carbonate rock in same

Abstract

Burning and cooling carbonate rock in cocurrent regenerative lime kilns may involve alternately operating two shafts such that a first shaft operates as a burning shaft and a second shaft operates as a regenerative shaft during a first period and such that the first shaft operates as the regenerative shaft and the second shaft operates as the burning shaft during a second period. Carbonate rock introduced to upper regions of the shafts may be preheated and calcined. The carbonate rock may then be cooled in lower regions of the shafts before being discharged through discharge devices. The cooling of the carbonate rock may comprise introducing cooling air into the shafts partially through central displacement bodies in the shafts and partially through the discharge devices. Amounts of air entering through the central displacement bodies compared to the discharge devices may vary widely from the burning shaft to the regenerative shaft.