Diagnosis method of rotary kiln interior

Abstract

A method for diagnosing the interior of a rotary kiln, which method permits one to make a correct determination as to the state of deposit of ash on the inner wall of the rotary kiln. According to the method, a detector is inserted into a gas stream from the rotary kiln and kept there for a certain period of time so as to allow ash to deposit thereon. Then, the weight, density and composition of the thus-formed deposit of ash are determined. The weight is corrected in view of the ash present in pulverized coal which was used as a fuel for burners, thereby obtaining corrected ash deposit weight (Wa). The weight is also corrected in accordance with the percentage of fine iron ores present in prefired pellets and the percentage of fine iron ores present in the deposit of ash and determined by the composition of the deposit and that of the fine iron ores, thereby obtaining corrected weight (Wd) of the deposited fine iron ores. The weight of ash deposited at an elevated temperature zone in the kiln is also determined as 'Ri' from Wd and the density of the deposit of ash. The extent of deposit of ash on the inner wall of the kiln is determined by comparing either one of the weight of the deposit of ash, Wa and Wd with its corresponding reference value while taking its density and optionally Ri into consideration. The above method permits one to enlarge the range of usable coal sources.