Influence of temperature of raw material into rotary kiln on temperature field distribution of kiln inlet system

Abstract

The residual decomposition reaction of calcium carbonate and the process of slow rise in material temperature in rotary kilns remain a bottleneck, which limits the growth in kiln capacity and reduction in energy consumption. Some researchers have put forward the idea of increasing the temperature of the raw material entering the rotary kiln. It was therefore considered worthwhile to study the influence of the temperature of raw material entering a rotary kiln on temperature field distribution of the kiln inlet system, including cyclone preheaters and a calciner. The characteristics were investigated by comparison of the calcination condition between a ‘six-level preheater + calciner’ and a ‘five-level preheater + calciner’ process. The data regarding temperature field distribution were obtained through numerical simulation. The results showed that when the ratio of calciner feed coal of the ‘six-level preheater + calciner’ process increased from 60 to 80%, the temperature of the raw material into the rotary kiln rose from 915 to 1220°C. The appropriate ratio of calciner feed coal for this was about 70%, and the temperature of raw material into the rotary kiln could reach 1070°C.