生物柴油燃料特性参数对NO_x排放影响的分析

Study of Influence of Biodiesel Properties on NO_x Emission

分析了生物柴油的燃料特性及脂肪酸组成结构,结合发动机燃烧生物柴油的试验,分析了燃料的十六烷值、密度、运动黏度、氧化安定性、不饱和双键的数量和位置等因素对NO_x排放的影响;运用FIRE软件分别模拟了生物柴油与柴油燃烧时的温度场、氧浓度场、黏度场以及十六烷值对滞燃期的影响规律。结果表明:生物燃料较低的十六烷值、较大的密度和运动黏度、较差的氧化安定性、存在双键且双键位置偏向脂肪链中间等,均会导致生物柴油NO_x排放升高。提出了降低NO_x排放的方法。

Based on analysis of the biodiesel properties and its fatty acid composition, the influences of fuel properties such as eetane number, density, kinematic viscosity, oxidation stability and number and position of unsaturated double bonds on NOx emission were investigated by engine test. The effects of temperature field, oxygen concentration field, viscosity field and cetane number on ignition delay period were simulated by using Fire software when fuelled with diesel and biodiesel respectively. The results show that low cetane number, high density and kinematic viscosity, poor oxidation stability, double bond and its position of the biodiesel fuel can lead to high NOx emission. Some measures to reduce NOx emission were also proposed.