Effects of ambient temperature on the combustion processes of single pulverized coal particle

Abstract

In the pulverized coal combustion, coal particles cross over a steep temperature gradient formed by a diffusion flame. This temperature gradient affects the particle temperature. This study has experimentally investigated effects of field temperature and residence time in high-temperature regions on the flame structure of single coal particles, since the substances of the devolatilization process varied due to the particle heating rate. The inlet velocity and the oxygen concentration of a laminar couterflow vary to control the residence time and the temperature gradient, respectively. A magnified two-color pyrometry was carried out to understand flame structure and the time series of flame and particle temperature. The results showed that the increase of oxygen concentration raises the volatile matter combustion temperature and flame diameter, and prolongs duration of the volatile matter combustion. The char combustion temperature decreases as the flow velocity increases. The maximum effective flame diameter increases linearly with increasing volatile matter combustion temperature regardless of particle size. This suggested an increase in flame interference distance. The maximum flame diameter increases monotonically with increasing volatile matter combustion temperature. the diluent the ignition of single-particle coal prolongs the duration of volatile matter an with a Hencken burner in an oxy-fuel and of coal particles. The simulation showed that it is essential to consider the CO 2 gasification reaction when simulating char combustion in an oxy-fuel combustion environment. Köser et al. performed highly repeated OH-LIF measurements on single coal particles. They used a laminar flow reactor that provided a hot oxygen-rich exhaust gas environment. Time-resolved imaging of the OH distribution at 10 kHz allowed to identify post-reaction and post-combustion zones and visualize the time evolution of coal particles during combustion. These studies show that a an increase in combustion temperature. interact with each other. Both of them change due to changes in field conditions. Therefore, the aim of this study is to clarify the effects of residence time and field temperature on the flame structure and temperature of the coal particle simultaneously. The temperature of the field and the residence time were changed by the O 2 concentration diluted with the inert gas nitrogen and the flow velocity. This study measured the time-series soot temperature, particle temperature, and particle diameter during pulverized coal combustion.