Simultaneous Determination of Na Concentration and Temperature during Zhundong Coal Combustion using the Radiation Spectrum

In this paper, a new measurement method based on flame emission spectrometry (FES) is applied to establish a functional model between Na concentration (C-Na), the temperature (T), and the radiation intensity of Na (I-Na589), namely I-Na589 = 1.2966 center dot I-b(lambda(589),T)center dot C-Na, in which the temperature and C-Na 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 C-Na of Zhundong coal pellets (raw, 40 degrees C water-washed, and 80 degrees 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 C-Na values of the raw, 40 degrees C water-washed, and 80 degrees C water-washed coal were 3.48, 1.91, and 1.43 ppm during the devolatilization phase, and the maximum C-Na 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.

Automated summary

This paper establishes a functional model between sodium concentration, temperature, and sodium radiation intensity using flame emission spectrometry. It is found that washing Zhundong coal pellets can effectively reduce the release of sodium, shorten ignition time, and improve combustion characteristics.