Department of Mechanical Biosystems, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O.Box 9177948974, Mashhad, Iran.
Department of Mechanical Biosystems, Faculty of Agriculture, Ferdowsi University of Mashhad, P.O.Box 9177948974, Mashhad, Iran.
Ultrason Sonochem. 2020 Jan;60:104672. doi: 10.1016/j.ultsonch.2019.104672. Epub 2019 Jul 4.
In the present study, the effect of ultrasound irradiation on the transesterification parameters, biodiesel properties, and its combustion profiles in the diesel engine was investigated. Moreover, date seed oil (DSO) was firstly utilized in the ultrasound-assisted transesterification reaction. DSO was extracted from Zahidi type date (Phoenix dactylifera) and was esterified to reduce its Free Fatty Acid (FFA) content. Biodiesel yield was optimized in both heating methods, so that the yield of 96.4% (containing 93.5% ester) at 60 °C, with 6 M ratio of methanol/oil, 1 wt% of catalyst (NaOH) and at 90 min of reaction time was reported. The ultrasound irradiation did not influence the reaction conditions except reaction time, reduced to 5 min (96.9% yield and 91.9% ester). The ultrasonic irradiation also influenced on the physicochemical properties of DSO biodiesel and improved its combustion in the diesel engine. The analysis results related to the engine and gas emission confirmed that the ultrasound-assisted produced biodiesel has lower density and viscosity, and higher oxygen content facilitating injection of fuel in the engine chamber and its combustion, respectively. Although, B40 (biodiesel blend consisting of 40% biodiesel and 60% net diesel fuel) as a blend of both fuels presented higher CO and lower CO and HC in the emissions, the DSO biodiesel produced by ultrasound irradiation presented better specifications (caused about 2-fold improvement in emissions than that of conventional method). The findings of the study confirmed the positive effect of the ultrasound irradiation on the properties of the produced biodiesel along with its combustion properties in the diesel engine, consequently reducing air pollution problems.
在本研究中，研究了超声辐射对酯交换参数、生物柴油性能及其在柴油机中燃烧特性的影响。此外，首次利用超声辅助酯交换反应从枣椰（Phoenix dactylifera）中提取枣椰籽油（DSO）并酯化以降低其游离脂肪酸（FFA）含量。在两种加热方法中优化了生物柴油产率，使得在 60°C 下，甲醇/油比为 6M，催化剂（NaOH）用量为 1wt%，反应时间为 90min 时，产率达到 96.4%（含 93.5%酯）。超声辐射除反应时间外，不影响反应条件，反应时间缩短至 5min（产率 96.9%，酯含量 91.9%）。超声辐射还影响 DSO 生物柴油的物理化学性质，并改善其在柴油机中的燃烧。与发动机和气体排放相关的分析结果证实，超声辅助生产的生物柴油具有较低的密度和粘度，以及较高的含氧量，分别有利于燃料在燃烧室中的喷射和燃烧。尽管 B40（由 40%生物柴油和 60%净柴油燃料组成的生物柴油混合物）作为两种燃料的混合物表现出较高的 CO 和较低的 CO 和 HC 排放，但通过超声辐射生产的 DSO 生物柴油具有更好的规格（比常规方法的排放改善了约 2 倍）。该研究的结果证实了超声辐射对所生产的生物柴油的性能及其在柴油机中的燃烧性能的积极影响，从而减少了空气污染问题。
