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Show V. Combustion Experiments For this part of the experimental program, a 0.352 m ID bed, refractory lined and water jacketed, (with two observation ports) was modified to be used for the swirl experiments. Since no external heat transfer surfaces were used, the flue gas was cooled by injecting water mist into the gas stream after the gas exit port. The freeboard swirl generator was installed between the two sections of the bed column. The optimized location of the swirl chamber ( 650mm above the distributor plate) was determined from the cold model, and gas traversing experiments. The swirl chamber was 152 mm high, and had four tangential air inlet ports. They were made from 2' galvanized pipes. See Figure 7 The fuel was delivered to the bed from the side of the bed through a horizontally placed, water cooled fuel nozzle; as opposed to vertically placed fuel nozzles located at the top of the column. This configuration eliminates the possibility of fuel particles being thrown at the column wall by the vonexing air flow, see Figure 8. The results obtained from the experiments carried out using secondary swirling air are presented in Figure 9 through Figure 11 . Although, because of the time constraints, we were not able to test the FBC unit for the whole range of variables considered, the results clearly indicate the staged combustion reduces NOx emissions considerably. More testing is needed in order to draw specific conclusions; i.e. swirl number settings, nozzle configuration, etc. WA TEA JAO<ET ...---520 ---~ ·····: 100 mm 7S mm \' '! ----1'-000----,;;::---000-.. - II • 1 Figure 7. The swirl block and the air nozzle 7 E E ,o.. . (>I |