Yilmaz Nadir, Vigil Francisco M, Donaldson Burl
Department of Mechanical Engineering, Howard University, Washington, DC, USA.
Los Alamos National Laboratory, NM, USA.
Sci Total Environ. 2022 Nov 25;849:157839. doi: 10.1016/j.scitotenv.2022.157839. Epub 2022 Aug 4.
Blends of biodiesel and high-carbon alcohols have the potential to increase the rate of biofuel use in diesel engines, while reducing harmful and toxic compounds such as polycyclic aromatic hydrocarbons (PAHs). Since biodiesel and alcohols do not contain aromatic ingredients in their chemical structures, this study examined biodiesel blends with propanol, n-butanol, and 1-pentanol (5 %, 20 % and 35 % by vol.) and the effects of these aromatic-free fuels on regulated emissions, PAH formation and toxicity as compared to straight diesel fuel in a diesel engine operating at a constant speed and varying engine loads. PAH samples were meticulously processed and extensively analyzed using rigorous analytical chemistry methodology (gas chromatography-mass spectrometry (GC-MS)). Biodiesel and biodiesel-alcohol blends significantly reduced NO emissions and the level of formation of PAHs and toxicity levels when compared to diesel fuel. Overall, adding 5 % alcohol to biodiesel decreased total PAH emissions. However, with the exception of 20 % propanol, adding 20 % and 35 % alcohol to biodiesel increased total PAH emissions as compared to neat biodiesel. In contrast, all blended fuels resulted in a decrease in the toxicity of PAH compounds (up to 70 %) and the percentage of higher-ring PAHs. Among higher alcohols, propanol blends stood out as reducing PAH formation as compared to n-butanol and pentanol blends. Overall, biodiesel-alcohol blends that emit less carcinogenic pollutants and primarily low-rings PAHs were found to be advantageous for reducing the likelihood of wetstacking in diesel engines under low load or cold operating conditions.
生物柴油与高碳醇的混合燃料有潜力提高柴油发动机中生物燃料的使用比例，同时减少多环芳烃（PAHs）等有害和有毒化合物。由于生物柴油和醇类在其化学结构中不含有芳香成分，本研究考察了生物柴油与丙醇、正丁醇和1-戊醇的混合燃料（体积分数分别为5%、20%和35%），以及这些无芳香燃料与直馏柴油相比，在恒定转速和不同发动机负荷下运行的柴油发动机中对常规排放、PAH生成和毒性的影响。使用严格的分析化学方法（气相色谱 - 质谱联用仪（GC - MS））对PAH样品进行了精心处理和广泛分析。与柴油相比，生物柴油和生物柴油 - 醇混合燃料显著降低了NO排放、PAH生成水平和毒性水平。总体而言，向生物柴油中添加5%的醇类可降低PAH总排放量。然而，除了20%丙醇外，与纯生物柴油相比，向生物柴油中添加20%和35%的醇类会增加PAH总排放量。相比之下，所有混合燃料都导致PAH化合物的毒性降低（高达70%）以及高环PAH的比例降低。在高级醇中，与正丁醇和戊醇混合燃料相比，丙醇混合燃料在减少PAH生成方面表现突出。总体而言，发现排放较少致癌污染物且主要为低环PAH的生物柴油 - 醇混合燃料有利于降低低负荷或冷运行条件下柴油发动机发生湿堆积的可能性。
