Abstract:

As a key performance index of lithopone calcination, the achromic power in a rotary kiln process is fluetuant. In order to ascertain the reasons for the fluctuation, a data series of the achromic power is analyzed. In the investigation, first, strong harmonics in the power signal are revealed via Fourier transform （FT） , which means that there is a certain periodicity of the achromic power fluctuation. Next, in order to find out the details of the fluc- tuation and deal with the non-stationarity, Hilbert-Huang transform （HHT） is used to analyze the marginal spectrum and spatial time-frequency distribution of the signal. Then, by the analysis of Hilbert spectrum, the time and duration of the fluctuation are obtained. Finally, on the basis of practical data, the reasons for the fluctuation are pointed out from the viewpoints of management and technique, thus helping to trace the quality accidents.

Key words: rotary kiln, achromic power, fluctuation, Fourier transform, Hilbert-Huang transform, marginal spectrum