生物柴油的抗氧化研究进展

生物柴油的氧化稳定性是影响生物柴油贮存与使用的关键问题。本文作者对生物柴油的组成特点、影响生物柴油氧化稳定性的因素及国内外生物柴油抗氧化性能的改善方法进行了分析,重点阐述了抗氧化剂对生物柴油抗氧化性能的影响。     

CA文摘

具有良好的储存稳定性的成膜液体清洁合成物及其使用方法,复合型柴油乳化剂配方,混合生物合成的生物可吸收支架,一种PVA吸水胶棉及其制备方法,通过喷射制造含对照剂和稳定剂的微球     

以生物柴油为介质的4%烟嘧磺隆油悬浮剂的配方研制

进行了以生物柴油作为分散介质的4%烟嘧磺隆油悬浮剂的研究,通过对乳化剂、稳定剂的筛选得到优化反应条件：以生物柴油作为分散介质;乳化剂m（农乳500）∶m（农乳600）=5∶5,总量为15%;稳定剂为有机膨润土,用量为2%。     

GX-105柴油稳定剂在催化裂化装置的应用

研究了GX-105柴油稳定剂对催化柴油的氧化沉渣和色度的稳定作用。结果表明,当温度为170℃,GX- 105柴油稳定剂的加注量为0．25 Kg/t时,催化柴油的稳定性较好,氧化沉渣和色度分别为2．5 mg/100 mL和3．0,与不加稳定剂时相比氧化沉渣和色度分别降低了17．5 mg/100 mL和4．5。     

生物柴油制备脂肪酸镧及其应用研究

用生物柴油即脂肪酸甲酯与氧化镧熔融反应制备脂肪酸镧,考察脂肪酸镧与硬脂酸锌、辅助稳定剂的配比和用量对聚氯乙烯热稳定性和机械性能的影响,结果表明：由生物柴油制备脂肪酸镧是可行的,亚磷酸二苯-季戊四醇酯与镧锌皂之间有协同作用,合成的镧锌复合稳定剂具有良好的热稳定性,优于某些其他工业产品。     

柴油稳定剂的研究进展

综述了柴油稳定刑的种类,指出柴油稳定剂主要是曼尼希缩合物、胺、氮杂环和醚类化合物等。并详细介绍了各稳定剂的性能及作用机理。另外,结合柴油稳定刑的现状,提出柴油稳定剂的未来发展方向。     

柴油-生物柴油-乙醇溶解性及其调和燃料特性的研究

以自制的生物柴油为助溶剂,研究了生物柴油对乙醇和柴油调和燃料的助溶作用;研究了不同比例的柴油-生物柴油-乙醇调和燃料的理化特性及稳定性。结果表明,当生物柴油含量为12.55%时,柴油和燃料乙醇可以以任意比例互溶;乙醇含量过高会导致燃料的各种理化性能下降;乙醇含量为10%,生物柴油含量>12.55%为混合燃料较为适宜的调和比列。     

提高柴油安定性的研究进展

论述了影响催化裂化柴油的氧化安定性的因素,介绍了多种非临氢精制方法的原理及最新的工艺技术进展,如酸碱精制、溶剂精制、吸附精制、加稳定剂法、盐精制和生物精制等,对各种精制方法进行了评价,提出FCC柴油非加氢精制的发展趋势是将各种精制工艺进行有机组合,形成新的非加氢精制工艺,以改善柴油的质量。     

催化合成生物柴油技术综述

生物柴油因具有优越的环保性、可再生性及使用安全性而受到广泛关注,是优质的石化柴油替代品,具有重要的经济和社会效益。本文介绍了生物柴油的国内外标准化现状,综述了通过酯化反应制备生物柴油的方法,包括均相及非均相的酸碱催化法、生物酶催化法及超临界催化法,分析了各种方法的制备过程、反应结果以及存在的问题,提出了生物柴油规模化发展的关键是开发高活性、高稳定性、高利用率的廉价催化剂以及环保且性价比高的生产工艺。     

生物柴油在制备PVC助剂中的应用

简单介绍绿色能源生物柴油深加工在制备增塑剂、稳定剂及润滑剂等PVC助剂中的应用。其中以制备环氧脂肪酸甲酯和氯代甲氧基脂肪酸甲酯最为经济可行。指出利用环氧脂肪酸甲酯制备多功能PVC助剂是重要的发展方向。     

生物柴油在制备PVC助剂中的应用

简单介绍绿色能源生物柴油深加工在制备增塑剂、稳定剂及润滑剂等PVC助剂中的应用。其中以制备环氧脂肪酸甲酯和氯代甲氧基脂肪酸甲酯最为经济可行。指出利用环氧脂肪酸甲酯制备多功能PVC助剂是重要的发展方向。     

Analysis of Sterol Glycosides in Biodiesel and Biodiesel Precipitates

Biodiesel is produced by the transesterification of vegetable oils with short chain alcohols, usually in the presence of an alkali catalyst. Minor components in biodiesel exist as a result of unreacted reagents, by-products, additives, and auto-oxidation products, such as water, free glycerin, bonded glycerin, free fatty acids, catalysts, residual alcohol, unsaponifiable matter (plant sterols, antioxidants, and hydrocarbons), soaps and polymers. The biodiesel properties, such as cold flow properties, acid number, cetane number, and oxidative stability are oftentimes significantly affected by these minor components. Sterol glycosides, as one of the most important minor components in biodiesel, and due to their polarities and limited solubility, can accelerate precipitate formation even at room temperature and possibly block fuel filters. In this paper, reversed phase high-performance liquid chromatography with an Evaporative Light Scattering Detector (ELSD) is evaluated for the analysis of sterol glycoside (SG) content in not only biodiesel precipitates but also in biodiesel. SG was found to be a major component in soy biodiesel precipitates and an SG peak was found in biodiesel after concentration by centrifugation.     

生物柴油氧化安定性的测定

本文研究了采用AOM法测定生物柴油的氧化安定性。试验结果表明,方法的标准偏差为0.152,变异系数为2.76%,并分别用AOM法和Rancimat法对六种生物柴油的氧化安定性进行测定,两法测定结果差绝对值为0.12～0.63h。     

The Effect of Natural and Synthetic Antioxidants on the Oxidative Stability of Biodiesel

A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. This study investigates the effectiveness of various natural and synthetic antioxidants [α-tocopherol (α-T), butylated hydroxyanisole (BHA), butyl-4-methylphenol (BHT), tert-butylhydroquinone (TBHQ), 2, 5-di-tert-butyl-hydroquinone (DTBHQ), ionol BF200 (IB), propylgallate (PG), and pyrogallol (PY)] to improve the oxidative stability of soybean oil (SBO-), cottonseed oil (CSO-), poultry fat (PF-), and yellow grease (YG-) based biodiesel at the varying concentrations between 250 and 1,000 ppm. Results indicate that different types of biodiesel have different natural levels of oxidative stability, indicating that natural antioxidants play a significant role in determining oxidative stability. Moreover, PG, PY, TBHQ, BHA, BHT, DTBHQ, and IB can enhance the oxidative stability for these different types of biodiesel. Antioxidant activity increased with increasing concentration. The induction period of SBO-, CSO-, YG-, and distilled SBO-based biodiesel could be improved significantly with PY, PG and TBHQ, while PY, BHA, and BHT show the best results for PF-based biodiesel. This indicates that the effect of each antioxidant on biodiesel differs depending on different feedstock. Moreover, the effect of antioxidants on B20 and B100 was similar; suggesting that improving the oxidative stability of biodiesel can effectively increase that of biodiesel blends. The oxidative stability of untreated SBO-based biodiesel decreased with the increasing indoor and outdoor storage time, while the induction period values with adding TBHQ to SBO-based biodiesel remained constant for up to 9 months.     

添加剂对橡胶籽油生物柴油氧化稳定性的改进

测定了橡胶籽油的物化性能及组成. 加入6种抗氧化剂,采用Rancimat法研究了其添加量及复配、温度、0#柴油添加量、金属铜、铁等对橡胶籽油生物柴油氧化稳定性能的影响. 结果表明,橡胶籽油所制生物柴油不饱和脂肪酸含量达82.1%,诱导期为0.81 h,达不到国家标准(6 h). 6种抗氧化剂在添加量为4000′10-6(w)时对橡胶籽油生物柴油的氧化稳定性能均有提升,其中TBHQ效果最好,使其氧化稳定性诱导期达13.09 h,6种抗氧化剂的抗氧化效果为TBHQ>BHT>D-TBHQ>OG>PG>BHA. PG与其他抗氧化剂复配后效果较好,而TBHQ与其他抗氧化剂复配后效果降低. 温度和0#轻柴油添加量对橡胶籽油生物柴油的氧化稳定性能影响很大,随温度升高,诱导期明显缩短,而随0#柴油添加量增大,诱导期增加,添加量较大时诱导期增幅很大. 铁、铜对其氧化稳定性能也有一定影响.     

微藻生物柴油的制备及其性能指标评价分析

以微藻毛油为原料,采用近临界醇解(SRCA)工艺制备微藻生物柴油,并分析了微藻生物柴油的各项指标.分析结果表明:微藻生物柴油的密度、运动黏度、闪点、含硫量、硫酸盐灰分、含水量、机械杂质、铜片腐蚀、十六烷值、酸值、游离甘油和总甘油等12项指标符合GB/T 20828-2007对调和用生物柴油BD100的要求;10％蒸余物...     

Soybean and Soybean/Beef-Tallow Biodiesel: A Comparative Study on Oxidative Degradation During Long-Term Storage

Vegetable oils are the primary raw materials used in biodiesel production; however, they usually present oxidative stabilities inferior to the EN 14214 specifications. An alternative to improve the oxidative quality of vegetable oil biodiesel is blending it with animal fat biodiesel. In this paper, we studied the oxidative degradation of soybean/beef-tallow biodiesel (SB) 70/30 and 50/50 (w/w) during long-term storage. Soybean biodiesel (SO) was used as a control sample. The biodiesel samples were stored for 350 days and analyzed periodically via oxidative stability, tocopherol content, peroxide value, polar compounds, and kinematic viscosity. The results showed that SB 70/30 and 50/50 biodiesel samples presented higher oxidative stabilities than SO biodiesel. Additionally, the blends met the limits proposed by EN 14214 for oxidative stability (8 h). During long-term storage, the SB biodiesel showed greater resistance to oxidative degradation, which was indicated by the lower formation of hydroperoxides and polar compounds. Similarly, the decline in the tocopherol content was slower in SB biodiesel. Blends of soybean and beef-tallow biodiesel at levels of 70/30 and 50/50 are, therefore, proper alternatives to improve the oxidative quality of this biofuel.     

The Effect of Antioxidants on Corn and Sunflower Biodiesel Properties under Extreme Oxidation Conditions

Biodiesel is an alternative to mineral fuels, with advantages such as biodegradability. However, this makes biodiesel unstable to oxidation. In this way, the use of natural or synthetic antioxidants is necessary. Although many studies have paid attention to the effect of these antioxidants on oxidation stability, not much literature about their effect of them on other properties (before and during storage) was found. The aim of this research study was to characterize biodiesel from corn and sunflower by adding two antioxidants, butylated hydroxyanisole (BHA) and tert-butylhydroquinone (TBHQ), in order to improve its oxidation stability. Moreover, the effect of oxidation on the parameters of biodiesel was studied by using extreme oxidation conditions to accelerate the oxidation process. Both antioxidants improved the oxidation stability of biodiesel, whereas some parameters were altered (viscosity and acid number), which could make this biofuel, if high concentrations of antioxidants are used, unsuitable for commercialization according to standards.     

Determination of Acid Number of Biodiesel and Biodiesel Blends

Due to an increase in the commercial use of biodiesel and biodiesel blends, both ASTM D 6751 and EN 14214 include the acid number (AN) as an important quality parameter. It was found that determination of AN of biodiesel and biodiesel blends using the ASTM D 974 results in large values of repeatability (up to 73.41%) and larger percentage error (up to 42.88%). Therefore, ASTM D 974 has been modified using a lower concentration of base (0.02 M KOH instead of 0.1 M KOH) as well as reducing the amount of toxic titration solvent from 100 mL to only 10 mL. This makes the modified ASTM D 974 as a green analytical method which uses a reduced amount of toxic solvent. This modified method significantly reduced the maximum percentage error from 42.88 to 5.92%. The application of this modified ASTM D 974 for the determination of AN of biodiesel and biodiesel blends was studied. The accuracy of this modified ASTM D 974 for biodiesel (B100) was measured to be within 3.51% over the AN range of 0.313–0.525 mg KOH/g and maximum repeatability was decreased from 8.37 to 2.75% within this AN range which is far below the ASTM D 974 stated repeatability specifications. For B20, B10, B5, B2, and B1, the most accurate values were measured at AN values of 0.177, 0.067, 0.072, 0.126, and 0.096 mg KOH/g, respectively. Excellent linearity values of R ² for calculated and experimentally determined AN were obtained. The difference between the experimental and the calculated AN for all biodiesel and biodiesel blend samples was within ± 0.018 mg KOH/g. This extensive study has demonstrated that this modified ASTM D 974 is a reliable method for the determination of AN and could be used for establishing the specifications of AN for biodiesel and biodiesel blends ranging from B1 to B20 in quality standards.