基于化学动力学的方法,建立了煤与生物质燃烧过程中氯化物和碱金属化合物的释放模型.以氯元素为例,将模型计算的结果与实验结果进行比较,验证了模型的可靠性.模拟生物质再燃过程时,将该释放模型补充到详细反应机理中,研究不同温度和浓度下,氯化物和碱金属化合物对NO释放的影响.结果表明,对NO的还原效果,碱金属化合物高于氯化物,NaOH高于KOH.氯化物和碱金属化合物通过影响自由基的浓度,进而影响NO的释放.以大同煤中的碱金属为例,用ηNO=AT-BT2+DC-E的形式拟合得到温度和浓度影响NO还原率的规律.
Based on the chemical kinetics, a model is proposed to describe the release rate of chloride and alkali-metal hydroxides in combustion of biomass and coal, which is validated through the comparison of calculating and experimental results of chloride. In the simulation of biomass rebuming, the model is extended into detailed reaction mechanism, which is applied to analyze the effects of chloride and alkali-metal hydroxides on NO reduction rate at different temperatures and concentrations. The results show that the effect of alkali-metal hydroxides is more obvious than that of chloride; the effect of NaOH is more obvious than that of KOH. These compounds may affect NO emission via the effect on the concentrations of some radicals. Taking Datong coal as an example, the effects of temperature (T) and concentration (C) of alkali-metal hydroxides on the NO reduction rate (no) can be expressed as r/No=A T-B T2 + DC-E.