Experimental research on ignition characteristics of pulverized coal

The effects of pressure, oxygen concentration, char structure and coal types on the ignition characteristics of Datong bituminous coal and Shenhuo anthracite under pressurized O2/CO2 atmosphere were investigated, two combustion characteristic indexes were used to evaluate the coal ignition and combustion characteristics. The results of pressurized thermogravimetric experiments indicate that the ignition temperature decreases firstly and then increases with increasing pressure from 0.1 MPa to 2 MPa, and it is lowest at 1 MPa. Under atmospheric and pressurized conditions, the ignition temperature decreases with the increase of oxygen concentration. At atmospheric pressure, the decrease of the ignition temperature is slow with increasing oxygen concen- tration, while at elevated pressure, the decrease of the ignition temperature is significant at higher oxygen concentration along with the transformation of the ignition mechanism. The scanning electron microscopy (SEM) micrographs suggest that the elevated pressure enhances the coal fragmentation during devolatilization, thus more surfaces are available for reaction, the oxidation rate is improved, and the ignition temperature dec- reases. The decrease of the ignition temperature with the increase of volatile content indicates that coal types also affect the ignition of coal. The results show that the pressurized oxy-fuel combustion is superior to the atmospheric oxy-fuel combustion. © 2013 Chinese Society for Electrical Engineering.