涡桨飞机VOCs排放特征的质子迁移反应飞行时间质谱(PTR-TOF-MS)分析

The proton transfer reaction time of flight mass spectrometer (PTR-TOF-MS) analysis of the turboprop aircraft emission of VOCs

涡轮螺旋桨飞机广泛应用于军事和民用通用航空领域,其发动机排放对区域大气VOCs浓度会产生重要影响,而我国目前几乎没有针对航空涡轮发动机VOCs排放的观测研究.基于此,本研究于2017年9月9日、14日和15日在北京沙河机场停机坪,利用质子迁移反应飞行时间质谱仪(PTR-TOF-MS)对运-12飞机涡轮发动机地面开车过程尾气中16类VOCs的排放开展了观测分析.结果表明,3次排放实验中VOCs的相对组成特征具有很高的一致性,甲醛和异戊二烯是占VOCs总浓度最高的两种物质,占比分别为30%和15%,乙醛、9碳芳香烃、10碳芳香烃和单萜的浓度占比在6%~8%之间,其它10种VOCs每种的占比都低于5%.发动机尾气中的VOCs与甲醛浓度具有很好的线性关系.VOC与甲醛排放量的比值与国外研究结果比较接近的VOCs有甲醇、乙醛和丙酮,比值分别为0.18、0.38和0.16 g·g^(-1),而芳香烃类物质与甲醛排放量的比值明显高于国外排放实验的结果.因此,未来有必要开展更多的研究以增进对国内航空发动机VOCs排放的认识.

Turboprop aircrafts are widely used in military and general aviation fields. Emission of VOCs from the engine of turboprop aircraft could impact the local air of VOCs significantly. However, there is almost no research concerning the emissions of VOCs from turboprop engines in China. On September 9, 14 and 15 of 2017, at the parking apron of Beijing Shahe airport, PTR-TOF-MS was used to measure the 16 VOCs of the Y-12 turboprop engine exhaust when running on the ground. Results show that the relative compositions of the VOCs among these three experiments have a high consistency: formaldehyde and isoprene account for the highest of the VOC concentrations and their concentration shares are 30% and 15%, respectively. Acetaldehyde, C9-aromatics, C10-aromatics and monoterpene accounts for the concentration of 6%~8% individually and the other ten VOCs accounts for no more than 5%, individually. The VOCs of the engine exhault have a good linear relationship with the concentration of formaldehyde. The VOCs having the VOC/formaldehyde emission ratios close to the ratios from the researches conducted in other countries are: methanol, acetaldehyde and acetone, with the ratios of 0.18, 0.38 and 0.16 g·g^(-1), respectivley. However, the ratios of aromatics emissions to formaldehyde emission are evidently larger than the values of the experiments finished in other countries. Therefore, it is needed to conduct more researches to enhance the comprehending of VOC emissions from aircraft engine in China.