Time-Series Temperature Measurement during Combustion of Volatile Matter and Coal Char of a Single Pulverized Coal Particle via Magnified Two-Color Pyrometry with Blue Backlit Imaging

摘要

In this study, a new technique was developed to measure time-series temperature during the combustion of volatile matter and coal char using magnified two-color pyrometry with high-speed blue backlit imaging. A steep temperature gradient was reproduced by supplying pulverized coal particles to a high-temperature region formed by a counterflow hydrogen/air diffusion flame. The time-series temperature measurement of the volatile matter combustion and surface combustion of a single pulverized coal particle was successfully performed with high-speed magnified imaging and two-color pyrometry. The results indicate that the particle size affects the volatile matter and char combustion. The estimation of the duration of the combustion of volatile matter from the existence of soot particles resulted in an average combustion duration of 3 ms and an average flame temperature of 2000 K under the 21% oxygen condition. The volatile matter combustion duration and flame size increased as the particle size of the coal increased due to an increase in the amount of volatile matter. The combustion temperature of the coal char decreased because the heat capacity of coal particles increased with an increase in the coal particle size.