H_(2)对NH_(3)在空气中燃烧影响的反应分子动力学

Effects of Hydrogen on Ammonia Combustion in Air:A Reactive Molecular Dynamics Study

氨被认为是一种具有发展前景的新型清洁能源,但其自燃温度高,不易燃烧。在NH_(3)中加入H_(2)可以改善其燃烧特性。采用基于反应力场的分子动力学方法研究H_(2)对NH_(3)在空气中燃烧反应的影响,揭示反应过程中NH_(3)分子数、氮氧化物(NO_(x))生成量、中间产物种类随温度和H_(2)添加量的变化规律,重点阐述NO_(x)的生成路径和H_(2)参与的反应路径。结果表明,H_(2)的加入降低了NH_(3)燃烧反应的活化能;随着H_(2)添加量的增加,体系中生成更多利于NH_(3)反应的H和HO自由基,从而提高NH_(3)燃烧速率;H_(2)对NO_(x)生成量的影响呈非线性变化,给出了能够降低NO_(x)排放的H_(2)掺混比例范围。

Ammonia is regarded as a promising new clean energy,but its spontaneous combustion temperature is high and it is not easy to burn.Adding H_(2)can enhance the combustion characteristics of NH_(3).The molecular dynamics method based on reactive force field was used to study the effect of H_(2)on NH_(3)combustion reaction in air,revealing the law of changes of NH_(3)molecular number,nitrogen oxide(NO_(x))generation,and intermediate species with temperature,and the H_(2)content.The reaction pathways relating to the production of NO_(x)and the reactions in which H_(2)participated were revealed.The results showed that the addition of H_(2)lowered the activation energy of NH_(3)combustion.Meanwhile,the addition of H_(2)can induce more H and HO radicals and thereby accelerate the NH_(3)combustion.The effect of H_(2)on the yield of NO_(x)was non-linear.A range of H_(2)addition was suggested to reduce NO_(x)emissions.