生物质再燃过程中气相成分浓度的变化规律

Variation Law of Gaseous Composition During Biomass Reburning Process

在一维恒温沉降炉上,采用1200℃的再燃温度对木屑、秸秆、稻壳3种生物质再燃区烟气中的主要成分随过量空气系数的变化规律进行了研究.结果表明:再燃脱硝效率及CxHy、CO的浓度随过量空气系数的增大而降低,NH3、HCN的浓度也呈明显的降低趋势;在相同的过量空气系数条件下,木屑的脱硝效率最高,其次是秸秆,稻壳最低;木屑再燃区的CxHy和CO浓度最高,氧浓度最低,表明其再燃区还原性气氛强于其他2种生物质;木屑再燃烟气中的NH3、HCN浓度明显高于秸秆和稻壳.对3种生物质再燃烟气中的TFN进行了计算,得出由于NH3、HCN在燃尽区氧化导致总脱硝效率降幅较小的结论.

Taking sawdust, straw and rice husk 3 kinds of biomass as an object of study, the law governing the variation of main gaseous composition in flue gas at reburning areas with excess air ratio was researched in a one-dimensional thermostatic drop tube furnace at a reburning temperature of 1 200 ℃. Results show that with the rise of excess air ratio, the reburning denitrification efficiency and the concentration of both CxHy and CO are all reduced, while NH3 and HCN show the same trend. For a same excess air ratio, sawdust produces the highest denitrification efficiency, followed by straw, and then rice husk. The high Cx Hy and CO concentration, and the low oxidation concentration measured in the reburning area of sawdust indicates that the reducing atmosphere of sawdust in that area is obiously stronger than other two species. In the flue gas of sawdust reburning area, the concentration of NH3 and HCN are obviously higher than that of other two kinds. Calculation results on TFN in reburning flue gas of the 3 biomass prove that the oxidation of NHa and HCN in the burnout zone has little influence in reducing the general denitrification efficiency.