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Show Oxy-Gas-Fired Glass Melter Field Test The Johns Manville, Cleburne, Texas furnace # 1902 was converted to oxygen firing in June 1997. This furnace is used for making glass marbles, which are converted into fiberized wool insulation. There are 10 Air Liquide A L G L A S S™ burners with a total firing rate capacity of 18.7 MMBtu/h. The burners are placed in a staggered configuration on both North and South sides. The furnace burner placement schematic is shown in Figure 14. The back wall burners 1-N and 1-S were not installed during the tests. Hue gas - \ \ \ \ * 1-N Bt*ncrto<n»o#« I" *" \ Batch .- ' --z. 1 „ A I H cin» CHCAGO BE3ARCH Cf' Figure 14. B U R N E R P L A C E M E N T IN T H E G L A S S M E L T ER A series of oscillating combustion tests were conducted on the furnace in the Summer of 1998 . The existing burner fuel piping was modified to include a bypass manifold with necessary isolation valves. The bypass piping was then retrofitted with CeramPhysics SSP valves (one per burner) upstream of each burner. Each SSP valve was thermally insulated and pairs of valves on opposite sides of the furnace were connected to an CeramPhvsics valve controller The furnace is generally run at a baseline oxygen/fuel ratio of about 2.20 and furnace pressure of 0.03" water column. Here the furnace flue gas has about 9.5 % excess oxygen and zero C O emissions. The furnace emissions were measured in the flue using a water-cooled sample probe, flue gas conditioning system and analytical instrumentation for N O , C O . C 0 2 and 02. Stack measurements were also performed to verify C O burnout. A series of parametric tests was conducted to define the oscillating amplitude, frequency and oxygen/fuel ratio for the maximum N O x reduction. The oscillating frequency was varied by an order of magnitude at the optimum amplitude level to optimize N O x reduction. The furnace operating parameters such as fuel and oxygen use. refractory and glass temperatures, bridge-wall optical temperatures, furnace pressure and levels were monitored as well as a continuous video recording of furnace interior. The fuel flow oscillations were centered at revised oxygen/fuel ratio of 2.00 to best reduce NOx emissions. Due to more fuel-rich operation, the average C O in the flue was 5000 ppmv. but the stack C O was less then 5 ppmv. This value would be much higher in the flue (>1.5%) if furnace was operated steady (without oscillations) at an oxygen/fuel ratio of 2.00, but excess air infiltration during oscillating combustion allowed the C O to burn out in the flue. Preliminary analysis of the emissions data at baseline and oscillating combustion conditions is shown in Table 6. The data in Table 6 indicate that oscillating combustion reduced N O x emission by 5 7 % from the regular baseline operation. The effects of various oscillating parameters on furnace emissions such as frequency and amplitude are still being analyzed, but lower oscillating frequencies and amplitudes provided higher N O x reduction and vice-versa. In addition, changing duty cycle should provide additional N O x reduction. Further, an extended (2-month) test is planned to get additional results on N O x reduction, fuel savings, improvement in productivity, and any changes in furnace operation. (afrc98pdoc) 11 |