Simultaneous Determination of Na Concentration and Temperature during Zhundong Coal Combustion using the Radiation Spectrum
Kuangyu Li, Weijie Yan, Lingbo Yu, Xianliang Huang, Yumin Chen, Huaichun Zhou, Shu Zheng, Chun Lou
Abstract
In this paper, a new measurement method based on flame emission spectrometry (FES) is applied to establish a functional model between Na concentration (CNa), the temperature (T), and the radiation intensity of Na (INa589), namely INa589 = 1.2966·Ib(λ589,T)·CNa, in which the temperature and CNa are simultaneously measured by the radiation spectrum. A combustion experiment was carried out to study the influence of water-washing on the combustion characteristics and the CNa of Zhundong coal pellets (raw, 40 °C water-washed, and 80 °C water-washed) at the heating environment temperature of 1600 K. The results show that water-washing effectively reduces the maximum and the total amount of Na released both in the devolatilization phase and the char phase. Among them, the maximum CNa values of the raw, 40 °C water-washed, and 80 °C water-washed coal were 3.48, 1.91, and 1.43 ppm during the devolatilization phase, and the maximum CNa values were 11.01, 6.57, and 5.18 ppm during the char phase, respectively. Moreover, water-washing was found to shorten the ignition time, lengthen the duration of the devolatilization phase and the char phase, and reduce the maximum temperature of the devolatilization phase and the average temperature of the char phase.