IGNITION CHARACTERISTICS OF BIAS PULVERIZED COAL JETS AT DIFFERENT INITIAL PULVERIZED COAL CONCENTRATIONS IN A REDUCING ATMOSPHERE

To further advance low NO_x pulverized-coal (PC) ignition theory, guide the parameter design of PC burner of bias combustion technologies and enable the related numerical simulation work, combustion experiments for an Indonesian coal were conducted in a 250-kW pilot-scale Bias Combustion Simulator (BCS); multiple research means of combustion temperatures and flame spectra were used. The effects of initial Pulverized Coal Concentration (PCC) on the standoff distance, ignition mode and continuous flame region of bias PC jets in a reducing atmosphere were investigated. The results indicate that with increasing initial PCC for bias PC jets in the experiments, the standoff distance gradually decreased, the peaks of subsequent combustion temperature and light emission intensity gradually increased, the continuous flame regions became gradually concentrated, the flame stability became gradually stronger, and the ignition characteristics gradually improved. The initial PCCs changed the ignition mode of bias PC jets; there was homogeneous– heterogeneous combined ignition mode at initial PCCs of 0.33 and 0.41kg/kg; there was homogeneous ignition mode at an initial PCC of 0.53kg/kg. At different initial PCCs, the continuous flame region of bias PC jets leant obviously in the direction of the fuel-rich jet.