| OCR Text |
Show Gaseous species are sampled continuously from the convective pass section outlet through a heated sample line. After filtering and drying, C O , C 0 2 , 02, and N O x concentrations are measured by calibrated analyzers. Fly ash is sampled across the duct via a multi-point probe with equally-spaced holes and analyzed for loss on ignition (LOI). Previous work [4] has shown that LOI measurements closely approximate the fly ash unburned carbon levels. Flue gas and fly ash sampling locations are shown in Figure 1. BURNER HARDWARE Two full-size, 100 MBtu/hr, unstaged, DRB-XCL® low-NOx PC burners with different throat velocities were tested in this program. Both burners had the same coal nozzle diameter and thus, the primary air velocity was held constant. But the overall barrel diameter of the plug-in burner was 1 5 % smaller than that of the full-diameter D R B - X C L burner. Figure 2 shows the main components of the standard DRB-XCL low-NOx PC test burner including the swirl vanes, conical diffuser, flame stabilizer, and air separation vane. Detailed description of the burner hardware can be found in an earlier paper [5] and therefore will not be repeated here. Briefly, the burner creates conditions that are conducive for converting fuel-N to molecular nitrogen by controlled mixing of fuel and air. Commercial installation of full-diameter DRB-XCL® P C burners in units previously equipped with circular burners has reduced N O x emissions by more than 5 0 % [6]. SUDE ADJUSTABLE DAMPER VANES Figure 2. DRB-XCL low-NOx P C burner - Standard configuration. 4 |
