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Show I Page 9 3. With the top burners blocked off, the flow from the lower burners extended horizontally toward the rear of the boiler and turned up the rear wall, over the nose and followed the noise; and turned toward the furnace exit. The overall shape was the desired liS" with the flames taking advantage of the entire furnace. 4. With the lower burners blocked off, the flow from the upper burners split exactly as described in Paragraph (1.) above. The observed reverse rollover in the flow model would affect the performance, flame length and location of the flames in the furnace. 5. With the upper burners reduced to 50% mass flow rate and the lower burners maintained at rated flow, the flow path through the furnace approached the ideal shape seen and described in Paragraph (3) above. 6. With the pilots removed and the center primary tube removed, the flow through the model appeared to fan out, soften and lengthen toward the rear wall. This reduced the impact of the nose's influence on the upper burners. 7. The test to demonstrate smaller burners, thus higher burner air loss and higher velocities, was worse than the existing installation. 8. The installation of a furnace floor deflector wall did not improve the flow path. After a joint review of the conclusions from the cold air flow testing, the boiler manufacturer and John Zink jointly presented to the owner on February 20, 1992 a program consisting of four possible improvements to be evaluated to lower the Nox without needing FGR and improve the flame pattern. |
