Pulverized coal flame structures at elevated pressures. Part 2. Interpreting NOX production with detailed reaction mechanisms

This study develops equivalent reactor networks from the CFD simulations for the pressurized coal flames described in Part 1, and quantitatively interprets the data by applying detailed reaction mechanisms across the reactor networks. These simulations depict all the important trends in the database with both coal quality and increasing pressure. The only quantitative discrepancy is that CO yields were under-predicted by roughly a factor of two throughout, although the predictions correctly indicate higher CO levels for coals of progressively lower rank. he reaction mechanisms were validated against the database, they were used to assess the impact of pressure on NOX production for realistic fuel injector configurations. These simulations, in conjunction with the test results, establish that (1) coal-N conversion to NO diminishes for progressively higher pressures under typical burner operating conditions; and (2) HCN tends to persist to higher stoichiometric ratios (S.R.) for progressively higher pressures, although it would not be present in flue gas prepared at a S.R. of 1.15 or greater at pressures to 3.0 MPa.