EGR组分对煤液化柴油颗粒排放的影响

为研究废气再循环（EGR）对煤液化柴油颗粒粒径分布，微观形貌，组成元素以及氧化特性的影响，运用扫描电镜（SEM），透射电镜（TEM）和热重试验的方法，通过改变EGR率（0% EGR，15% EGR）和废气组分（15% N₂，15% CO₂和30% CO₂）采集了柴油机燃用煤液化柴油的颗粒，分析了颗粒微观结构和氧化特性.结果表明，EGR率小于15%时，颗粒粒径呈单峰正态分布.在0% EGR，15% EGR，15% N₂，15% CO₂氛围下，颗粒粒径分布的峰值粒径分别为60.4，60.4，69.8，52.3nm.引入30% CO₂时，颗粒粒径呈双峰正态分布，粒径分别在14.3nm和52.3nm.引入EGR和N₂后，颗粒群变得紧凑，不易氧化.引入CO₂后，颗粒群变得疏松，易于氧化.不采用EGR，颗粒结构主要呈链状，引入15% EGR和15% N₂，颗粒结构主要呈团簇状.

Effects of EGR components on particle of coal liquefied diesel

The aim of this study is to evaluate the effects of exhaust gas recirculation (EGR) on particle size distribution, microscopic morphology, compositional elements, and oxidation characteristics of particles from coal liquefied fuel engine. Particles from the engine fueled with coal liquefied fuel were collected under different EGR ratio (0% EGR, 15% EGR) and exhaust gas composition (15% N₂, 15% CO₂ and 30% CO₂). The micro structure and oxidation characteristics of the particles were analyzed by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analyzer. The results showed that when the EGR rate is less than 15%, the particle size shows a single peak normal distribution. The peak diameters of particle size distribution were 60.4, 60.4, 69.8 and 52.3 nm in the condition of different EGR ratio of 0% and 15%,different composition of 15% N₂ and 15% CO₂ respectively. When 30% CO₂ was introduced, the particle size showed a bimodal normal distribution with particle sizes of 14.3 nm and 52.3 nm respectively. After the introduction of EGR and N2, the particle group becomes compact and was not easily oxidized. After the introduction of CO₂, the particle group became loose and easily oxidized. Without EGR, the particle structure was mainly chain-like, and introducing 15% EGR and 15% N₂, the particle structure was mainly clustered.