A Simplified One-Dimensional Model of Low NOx Ignition for the Direct Flow of Pulverized Coal

This study developed a new model for the low NOx ignition for the direct flow of pulverized coal, which enabled the influence of the primary air and internally recirculated flue gas (RFG) on NOx formation to be investigated. A model of the preignition zone was discussed in detail. Three new parameters, the Local Stoichiometric Ratio of Volatiles(LSRV), the Virtual Temperature of Ignition (VTI) and a Gxnumber to indicate NOx reduction potential were introduced to analyze the influence of the primary air/RFG parameters on low NOx ignition. It was found that coal volatiles and size had a major impact on establishing the primary air parameters and ignition position which are favorable for low NOx combustion. The model can be used to determine the necessary mixing parameters for the design or modification of boilers for low NOx coal combustion.