Continuous Measurement and Control of Sinter Mix Moisture for Decrease in Sintering Fluctuation

Abstract

To decrease carbon dioxide emission in iron ore sintering process through reduction of carbon consumption as sintering agent, reduction of fluctuation in iron ore sintering was studied. Transition phenomena of the sintering fluctuation through a sintering plant were observed and studied using a frequency analysis.The sintering fluctuation was defined as the cyclic change in the exhaust gas temperatures at a certain wind-box. The observation of the wind box temperatures showed that the temperature changes of several minute cycles existed. To search for upstream causes, charging behavior of the sinter mix to pallet cars was observed using an index of “charging level”. Comparison of the charging level and the wind box temperature showed that the fluctuations of them were almost coincident in the occurring time and position. To search for further upstream causes, a near-infrared moisture meter was introduced to measure sinter mix moisture with high frequency. To investigate the relationship between the wind box temperature, the charging and the sinter mix moisture, a frequency analysis of the fluctuations of them was carried out. It showed that some frequency elements were almost coincident and that fluctuation transferred from the fluctuation in the sinter mix moisture to the sintering.Then, a test operation of more precise control of the sinter mix moisture using the near-infrared moisture meters in a sintering plant was carried out. It successfully reduced sintering fluctuation.