Numerical Simulation of Low NOx Combustion Technology in a 100 MWe Bituminous Coal-Fired Wall Boiler.

Computational fluid dynamics (CFD) has been applied to evaluate two NOx reducing schemes in a 100 MWe per hour (p/h) boiler that uses double volute burners without over-fire-air (OFA). The new schemes involve: a) changing the double volute burners for centrally fuel rich (CFR) burners, and b) using the OFA system in conjunction with a). In analyzing the results of these two schemes, various conclusions were drawn: 1) gas temperatures and related rise rates in the central zone of burners were higher, O2 and NOx concentrations were lower; and 2) cross-sectional gas temperature distributions through the burner centers in scheme employing b) is higher than that of original furnace set-up, and lower than that of scheme employing a). Comparing the b) scheme with those of the a) scheme and the original set-up, which is 277 mg/m3 (at 6% O2) at the furnace outlet, the peak value of NOx concentration has decreased 571 mg/m3 (67.4%) and 436 mg/m3 (61.2%), respectively. [ABSTRACT FROM AUTHOR]