Patent ID: 6474984
Filing Date: 2002-11-05
Classification: C04B,F27B

Abstract:
A calcining system operating in a substoichiometric mode for reducing nitrogen oxide generation and removing sulfur from materials to be processed by creating an oxygen deficient atmosphere, the calcining system comprising:a rotary kiln rotating on a slightly inclined horizontal axis, the rotary kiln having a feed end introducing material to be processed and a discharge end; a preheating/precalcining device positioned adjacent the feed end wherein the material passes through the device prior to entering the rotary kiln; a stationary hood positioned adjacent the discharge end of the rotary kiln; a burner protruding the stationary hood, the burner introduces combustible fuel and combustion air into the rotary kiln through the discharge end and operating in a substoichiometric mode; and at least one air nozzle spaced between the feed and discharge ends of the rotary kiln, the air nozzles injecting combustion air into the rotary kiln wherein the combustion air introduced by the air nozzles completely combusts the combustible fuel introduced by the burner before the combustible fuel exits the feed end.