| As the global warming and climate change due to greenhouse effects are continuing serious, oxyfuel combustion, which can achieve the capture of CO2 and removal of multipollutants synchronization, has been given the growing worldwide interest as a potential option for climate change mitigation.The numerous simulations with FLUENT and pilot scale tests are carried out to research the aerodynamic performance and combustion characteristics of the oxyfuel burner. A single-register, swirl-stabilized burner with the primary stream being admitted to an annulus located inside the swriled secondary stream. Small amounts of O2 is admitted directly to the combustor through the central O2 pipes; most O2 is added to the secondary streams. A lot of numerous simulations with CFD are carried out to find out the best swirl strength. The axail velocity field is drawn to study the central recirculation region of the burner; the stream mixing condition is photographed and observed in the flow visualization. The good aerodynamic performance of the burner are shown in the cold-state experiments.The combustion tests in air condition and recycled flue gas condition(RFG) are carried out. It indicates that, pulverized coal ignition and combustion is quick and stable. The NO, SOx volumetric concentration is 1.8 times and 3 times of that in air case respectively. When the O2 rate is lower in the central O2 pipes, which means the O2 rate in the second stream is higher, the NO volumetric concentration is decreased significantly; the SOx is almost unchanged. While the unit mg/MJ is used for the NO, SOx amount, the denitrification and desulfurzation percent is 60% and 30% (based on the air condition). When the O2 rate in the central O2 pipes is lower, the denitrification rate is further improved to 67.1%; the SOx is almost unchanged.The research shows when the reduced O2 in the central O2 pipes is added to the second stream, the NO formation drops significantly, which is useful for the design of the oxyfuel burner. |
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