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Show Figure 7: ABB PPL's Boiler Simulation Facility The aerodynamic characteristics of a typical ABB C-E utility boiler are also replicated, including the tangential firing pattern. A n arch section separates the lower furnace from the upper furnace. The upper furnace includes simulated superheater and reheater panels. Downstream of these panels, the furnace gases are quenched below practical C O oxidation temperature levels in a convective pass formed from a series of tube bundles. The BSF has demonstrated the ability to generate NOx emissions levels consistent with utility boiler measurements on similar, retrofitable, combustion system arrangements. For example, Grusha and McCartney reported a comparison of the performance of an earlier low N O x firing system design tested in the BSF against its measured performance in a 160-MWe utility boiler in Italy.4 This comparison is shown in Figure 8, in which N O x emissions are plotted against stoichiometry for both field and BSF tests. Similar coals and firing systems were used to collect each set of data. Good correlation between the BSF and field data is evident. Similar comparisons with carbon-in-flyash data have shown that the BSF accurately predicts the field-observed percentage change for the carbon-in-flyash from the baseline to the low N O x conditions. typically less amenable to staged combustion, particularly when striving simultaneously for both low N O x emissions and low unburned carbon-in-flyash. The ASTM classifications for the tested coals are: medium volatile bituminous for Coal A; high volatile A bituminous for Coals B and C. Boiler Simulation Facility (BSF) Description The BSF operates at 15 to 30 MW thermal heat input, and is shown schematically in Figure 7.3 All major aspects of a typical ABB C-E utility boiler are duplicated in the BSF, including the lower furnace, the ash hopper, multiple burners, the arch section, superheater and/or reheater panels, and convective heat transfer surfaces. The furnace walls and heat transfer surfaces are cooled by a surrounding water jacket and are selectively lined with refractory to maintain a typical furnace gas horizontal exit temperature and time/temperature history (i.e. quench rate). This replicates full-scale combustion reaction rates. 9 11-10 |