Study on Factors Influencing Pulverized Coal Ignition Time

Abstract

Pulverized coal ignition time is one of crucial parameters in coal ignition process. Based on a general heat absorption equation without chemical reaction, this study was focused on some crucial factors which influence pulverized coal ignition time to theoretically explain the mechanism of heat absorption of pulverized coal. The influences of recirculated flue gas (RFG) temperature, flame temperature, primary air temperature, and coal particle diameter on ignition time were discussed. The importance of radiation heat and convection heat was analyzed. The results show that the higher temperatures of RFG, flame, and primary air can lead to the shorter ignition time respectively. The increase of the coal particle diameter greatly increases the ignition time, and as the diameter goes up, the amount of the ignition delay becomes greater. For high accuracy of ignition time calculation, both radiation heat and convection heat should be taken into account. When flame temperature is very high and RFG temperature is very low, radiation is the dominant factor, otherwise convection is more crucial.