生物质废弃物的再燃脱硝实验研究

Experimental study on NO reduction by reburning of biomass wastes

利用模拟烟气在两段式管式炉中对树皮、锯末、污泥等生物质废弃物的再燃脱硝特性进行了实验研究,在再燃和燃烬温度分别为1 250,1 150℃下进行再燃+燃烬两段完整的热态脱硝实验。结果表明,再燃时的空气系数在0.90～0.95时,树皮、锯末、污泥等生物质废弃物的再燃脱硝效率可达90%。对再燃中间产物HCN/NH3的生成特点进行了检测,并采用Fe2O3来控制HCN/NH3的生成,进一步完成了Fe2O3与上述燃料混合后的再燃+燃烬脱硝实验。结果表明,当Fe2O3的摩尔比超过4×10-3时,造纸污泥和锯末的再燃+燃烬的最终脱硝效率超过70%,并逐渐接近天然气在相同条件下的脱硝效率,表明这些废弃物可以作为替代再燃燃料。

The NO reduction by reburning of biomass wastes, i. e. , wood bark, wood fine and paper mill sludge, was ex- perimentally studied in a two-stage furnace with simulated flue gas. NO reduction efficiency was tested at reburning temperature of i 250 ℃and burnout temperature of i 150 ℃ respectively. The results show that NO reduction efficien- cy during reburning of these biomass wastes achieves 90% when the reburning stoichiometrie ratio is in the range of 0. 90-0.95. The intermediate products during reburning,HCN/NH3 ,were examined and Fe203 was selected to con- trol the formation of HCN/NH3. A further test on both reburning and burnout was conducted by mixing Fe2O3 with above biomass fuels. The results show that the final NO reduction efficiency after reburning and burnout of wood fine and paper mill sludge exceeds 70% and finally comes close to the efficiency of methane when the mole fraction of Fe2O3 is higher than 4×10-3 ,which demonstrates that the biomass wastes can be used as alternative reburning fuels.