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采用Chemkin4.1化学动力学软件,基于详细反应机制的柱塞流反应模型对生物质热解气及其成分气再燃还原NO反应过程进行机制分析和数值模拟研究。给出再燃燃料不同成分气CH4、CO、H2反应还原NO的特性和主要反应,得出CH4具有NO最佳还原效率,并给出最佳反应温度。由于秸秆更高的气相产率和热解气中更多的CH4含量,一定反应条件下,秸秆的热解气脱硝率比稻壳高。入口烟气中的氧气含量对脱硝率具有重要影响,氧量较高时对NO还原影响大的反应活化基团将大量被氧化而减少,使脱硝率降低。计算结果表明,热解气成分中对再燃还原NO起主要作用的是CH4,而CO和H2等成分影响较弱。通过敏感性分析得出:生物质热解气反应中,O和OH为诱导反应发生的主要自由基,CHi+NO和HCCO+NO为消耗NO的主要途径。
Chemkin4.1 chemical kinetics software and plunger reaction model based on detailed reaction mechanism were used to study the mechanism and numerical simulation of the NO reaction of biomass pyrolysis gas and its component gas for reburning reduction. The characteristics and main reactions of NO reduction of CH4, CO and H2 with different components of the re-fueling gas were obtained. The optimal NO reduction efficiency of CH4 was obtained and the optimum reaction temperature was given. Due to the higher gas phase yield of straw and the more CH4 content in the pyrolysis gas, the denitrification rate of straw by pyrolysis gas is higher than that of rice husk under certain reaction conditions. The oxygen content in the inlet flue gas has an important effect on the denitrification rate. When the oxygen content is higher, the reactive groups that greatly affect the NO reduction will be oxidized to a large extent, reducing the denitrification rate. The calculated results show that CH4 is the main component of the pyrolysis gas for reburning NO, while the composition of CO and H2 is less affected. Through sensitivity analysis, we found that O and OH are the main free radicals during biomass pyrolysis gas reaction, and CHi + NO and HCCO + NO are the main ways to consume NO.