Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159966. doi: 10.1016/j.scitotenv.2022.159966. Epub 2022 Nov 5.
In China, natural gas (NG) is the main vehicle fuel after gasoline and diesel, and the number of NG vehicles ranks first in the world. At present, there are many studies on the conventional gaseous pollutants and particulate matter of NG vehicles, but very few studies on their VOCs. In this study, the chassis dynamometer is used to test CNG/E10 bi-fuel light-duty vehicles, analyze the advantages of CNG in CO, fuel thermal efficiency, and cost, and discuss its disadvantages in NO emission. Most importantly, the emission characteristics and ozone formation potential of VOCs in the exhaust of CNG vehicles were analyzed in the study. Compared with E10, CNG fuel can reduce CO emission by about 20 %, improve thermal efficiency by about 13 %, and save fuel costs by about 50 %. However, it will increase NO and NO emissions by about 10 % and 13 % respectively. As for VOCs, the emission factor of VOCs from CNG fuel is about 54 % of E10 fuel. The VOCs group with the highest proportion in the exhaust of CNG-fueled vehicles is alkanes, >80 %. while the alkanes and alkenes with the highest proportion in E10 fuel are 30 % and 23 % respectively. C2 VOCs emitted by CNG account for >70 %, while C2 VOCs emitted by E10 are <60 %, followed by C4 VOCs, about 10 % - 30 %. The OFPs of VOCs in CNG exhaust is about 13.7 % of E10. Alkenes contribute the most to ozone, and the OFPs of alkenes in CNG and E10 vehicle exhaust accounts for about 55.3 % and 78.8 % of TVOCs respectively. The results of this study are helpful to improve people's understanding of the environmental value of using NG vehicles.
在中国，天然气（NG）是继汽油和柴油之后的主要车辆燃料，NG 车辆的数量位居世界第一。目前，针对 NG 车辆的常规气态污染物和颗粒物已有很多研究，但对其挥发性有机化合物（VOCs）的研究却很少。在本研究中，使用底盘测功机对 CNG/E10 双燃料轻型车进行了测试，分析了 CNG 在 CO、燃料热效率和成本方面的优势，并讨论了其在 NO 排放方面的劣势。最重要的是，本研究分析了 CNG 车辆尾气中 VOCs 的排放特征和臭氧形成潜力。与 E10 相比，CNG 燃料可将 CO 排放量减少约 20%，热效率提高约 13%，燃料成本降低约 50%。然而，它将分别增加约 10%和 13%的 NO 和 NOx 排放。对于 VOCs，CNG 燃料的 VOCs 排放因子约为 E10 燃料的 54%。在 CNG 燃料车辆尾气中排放比例最高的 VOCs 组是烷烃，>80%。而 E10 燃料中比例最高的烷烃和烯烃分别为 30%和 23%。CNG 排放的 C2 VOCs 占>70%，而 E10 排放的 C2 VOCs 则<60%，其次是 C4 VOCs，约为 10%-30%。CNG 尾气中 VOCs 的 OFP 约为 E10 的 13.7%。烯烃对臭氧的贡献最大，CNG 和 E10 车辆尾气中烯烃的 OFP 分别约占 TVOCs 的 55.3%和 78.8%。本研究的结果有助于提高人们对使用 NG 车辆的环境价值的认识。
