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Show Parametric Testing. Four series of subsystem tests have been completed in the CEDF thus ~~ The first round of testing was performed to confirm scale up from pilot -scale and numenc modeling, and to obtain some initial observations of the advanced low-NOx burner near fu~l-scaled The design lllinois #6 coal was used for testing to stay consistent with the pilot-scale test~ng a~ numerical modeling. Minor hardware changes and various mixing devices were tested du~ng this initial round of subsystem testing. Operating conditions, including load and excess alf~ ~ere varied for each hardware configuration and data were collected in terms of operating condItIOnS, stack gaseous emissions, and fly ash samples. The initial round of subsystem testing showed that the advanced 10w-NOx burner provides lower NOx emissions in comparison to the DRB-XCL ®. However, complete conclusions about the advanced 10w-NOx burner were being reserved until further optimization tests could be performed through experimental testing and numerical modeling. Although minor modifications were in order for the advanced low-NOx burner, the general hardware configuration was found to be promising and therefore, the burner was designated DRB-4ZTM. This name provided a continuity with the low NOx DRB product line from which it originated, while still accommodating its uniqueness. The second, third, and fourth series of tests focused on optimization of the DRB-4ZTM burner in an unstaged firing configuration. Various hardware changes were made affecting the air and coal distribution. From these tests, an optimum burner configuration was determined. This design will be used for staging tests scheduled to begin in late October. Parametric testing was performed for each burner configuration. Tests were performed by varying the air distribution, primary air-to-coal ratio, burner stoichiometry and load. The data collected were averaged over the time frame of the test and were plotted for each configuration separately, while the optimum conditions were compared collectively. Two coals were frred during the initial burner testing: the lllinois #6 design coal, and a Mahoning 7 A coal. The Mahoning coal had been used for part of the characterization testing of the CEDF. A Kentucky #9 coal was selected for use during the second series of tests because it had characteristics similar to that of the lliinois #6, but a slightly higher fixed carbon-to-volatile matter ratio. It was determined that the Mahoning 7A coal showed the most sensitivity with respect tq NOx, CO, and UBC values, therefore, it was decided to utilize this coal for the third and fourth series of tests. However, the coal supply company was mining at a different location of the seam, obtaining a coal (Ohio #7) with a higher fixed carbon-to-volatile matter ratio. Consequently, a Ohio #7 coal was utilized for the third and fourth rounds of testing. The DRB- 4ZTM burner was also utilized during the Combustion 2000 SOx subsystem testing, firing an Ohio blend coal from the Horizon Wash Plant. This blend of Ohio coals was also used during a previous test in the CEDF with the DRB-XCL ® burner. Limited data was acquired while firing the Ohio blend (no parametric data), however, this information is being provided for an overall comparison. Table 2 shows the proximate and ultimate analysis for the test coals. Results from the parametric tests involving changes in air distribution tended to show the same preferences for the burner configuration. By changing the air flow pattern definite changes were noted in the emissions performance. This information corresponded to the modeling case studies , Page. 9 |