NOx control through reburning using biomass in a laboratory furnace: Effect of particle size
NOx control through reburning using biomass in a laboratory furnace: Effect of particle size
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DOI：
10.1016/j.proci.2008.06.138
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
C. Casaca;Mário Costa
中科院分区：
文献类型：
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作者：
C. Casaca;Mário Costa
本文描述了一项实验研究，旨在评估再烧燃料的粒度分布对大型实验室炉中再燃烧过程减少氮氧化物排放的有效性的影响。稻壳具有三种不同的粒度分布，被用作再燃烧燃料。最初，烟气数据（气态污染物和颗粒燃尽）是通过“三”稻壳在各种实验条件下获得的。随后，为了加深对再烧效率与再烧燃料颗粒尺寸之间关系的理解，对使用“三”稻壳的三种炉子运行条件下的再烧区局部平均 O2、CO、CO2、HC 和 NOx 浓度以及气体温度进行了详细测量。结果表明，对于目前的燃烧器和操作条件，存在通过再燃烧增强氮氧化物还原的最佳颗粒尺寸范围。低于或高于稻壳的最佳粒度范围，再燃烧机制不太有效，可能是因为生物质脱挥发分过程分别在再燃烧区域末端之前完成或延伸远远超出再燃烧区域的末端，从而阻碍了 NO 与 CHi 和 HCCO 的接触，并促进了 CHi 和 HCCO 与氧气的相互作用。此外，结果表明，无论稻壳颗粒尺寸范围如何，随着NOx还原量的增加，颗粒燃尽略有下降。鉴于目前的燃烧室只有顶部部分和上面四个部分衬有一层耐火材料，可以预期，在全尺寸设备中使用稻壳作为再燃燃料的再燃烧对颗粒燃尽的影响甚至比本研究中观察到的还要低。
This article describes an experimental study to evaluate the effect of the particle size distribution of the reburn fuel on the effectiveness of the reburning process to reduce NOxemissions in a large-scale laboratory furnace. Rice husk, with three distinct particle size distributions, was used as reburn fuel. Initially, flue-gas data (gaseous pollutants and particle burnout) was obtained for a wide range of experimental conditions with the “three” rice husks. Subsequently, in order to improve the understanding of the relationship between reburning effectiveness and reburn fuel particle size, detailed measurements of local mean O2, CO, CO2, HC and NOxconcentrations, and gas temperatures have been gathered from the reburn zone for three furnace operating conditions that used the “three” rice husks. The results suggest that, for the present combustor and operating conditions, there is an optimum particle size range for enhanced NOxreduction through reburning. Below or above the optimum particle size range of the rice husk the reburn mechanism is less effective probably because the biomass devolatilization process either finishes before or extends well beyond the end of the reburn zone, respectively, impeding the exposure of NO to CHiand HCCO and facilitating the CHiand HCCO interaction with oxygen. In addition, the results show that the particle burnout decreases slightly as the NOxreduction increases, regardless of the rice husk particle size range. Given that the present combustor has only the roof section and the upper four segments lined with a layer of refractory, it can be anticipated that reburning using rice husk as reburn fuel in full-scale equipment would have even a lower impact in particle burnout than that observed in this study.