加EVAP前后柴油中蜡生长形态变化

利用低温显微技术对添加降凝剂EVAP前后柴油中蜡的生长形态变化进行了实时观测研究,同时利用X射线衍射技术研究了加剂前后蜡晶微观结构的变化。研究表明,在柴油中添加降凝剂后,蜡的分散度、完整度、结晶度都得到了明显的提高,从而改善了柴油的低温流动性能。     

生物柴油低温流动性及改进方法研究进展

综述了生物柴油低温流动性评价指标、主要影响因素及改进方法等相关研究进展。介绍了生物柴油中的脂肪酸组成和分布、酯基结构及杂质组成与生物柴油低温流动性能的关系。论述了改善生物柴油低温流动性的几种主要方法:加入添加剂法、改变生物柴油结构、冬化处理等。其中加入添加剂法成本低,操作方便,将成为改进生物柴油低温流动性能的研究方向。     

铁刷镀层低温渗硫试验研究

利用光学显微镜，电子显微镜Ｘ射线衍射技术，显微硬度计和磨损试验对铁镀层低温渗硫前后的组织与性能进行了研究。结果表明：铁刷镀层经低温渗硫后，镀层表面渗入一层黑色物质，呈层状结构，组织均匀，渗硫层深度为１５－２０μｍ，该层主要成分为ＦｅＳ及少量的其它硫化物。同时镀层的显微硬度升高，磨损率显著下降。     

显微分析技术在涂料中的应用研究

显微分析技术为研究微观结构提供了强有力的技术支持,目前显微分析技术大致可以分为两类,一类是光学显微分析技术,另外一类是电子显微分析技术。在涂料行业中最常用的是光学显微镜、扫描电镜能谱和显微红外光谱分析技术,本文就这几类技术的原理和应用展开讨论。     

304奥氏体不锈钢低温盐浴氮化处理及其耐蚀性

采用低温(430°C)盐浴对304奥氏体不锈钢进行氮化处理,研究了氮化时间对渗氮层组织、显微硬度及耐蚀性的影响。分别用X射线衍射仪(XRD)、表面显微硬度计、光学显微镜分析了渗氮层的相组成、显微硬度、截面形貌和厚度。结果表明,304不锈钢表面的渗氮层厚度和显微硬度都随处理时间的延长而增大。氮化处理1h得到的渗氮层由单一的S相组成。经盐浴渗氮处理的304不锈钢,其耐Cl-点蚀性能得到改善,430°C下氮化4h得到的渗氮层耐蚀性能最好。     

LDY柴油降凝剂的性能评价

在分析中国石油辽化炼油厂0^#柴油的烃族组成、蜡碳分布的基础上，研制出一种柴油低温流动性改进剂。实验结果表明，这种柴油低温流动性改进剂能十分有效地提高中国石油辽化炼油厂0^#柴油的低温使用性能。并在实验室评价了LDY柴油降凝剂对几种0^#柴油的低温流动性能的改进效果。     

降凝剂加剂量对组成不同的-35号车用柴油冷滤点的影响分析

通过实验数据对比分析,对添加柴油低温流动性改进剂后的-35号车用柴油的冷滤点进行分析断判,通过降凝降滤效果,找出炼油化工生产低温性能柴油的最佳调配比,改善油品低温性能,为柴油调和生产提高经济效益。     

生物柴油低温流动改进剂复配研究

采用碱催化法制备菜籽油生物柴油和棕榈油生物柴油,对其主要品质指标进行分析;考察了添加不同的柴油低温流动改进剂及其复配物对生物柴油低温流动性能的影响。结果表明,柴油低温流动改进剂能够改善生物柴油低温流动性能;将其进行复配后,能表现出协同效应,取得更好的降滤效果,尤其能使饱和脂肪酸甲酯含量高的棕榈油生物柴油冷滤点降低8℃;不同生物柴油对柴油低温流动改进剂或其复配物感受性存在较大差异,不饱和脂肪酸甲酯含量高,且脂肪酸甲酯种类较多、分布较广的菜籽油生物柴油对单一低温流动改进剂感受性好,而饱和脂肪酸甲酯含量高,且脂肪酸甲酯种类分布较集中的棕榈油生物柴油对复配物感受性好。     

生物柴油低温流动性能研究进展

生物柴油是清洁可再生燃料,越来越多的国家开始研究和使用生物柴油替代石化柴油。然而生物柴油凝点和冷滤点很高,低温情况下容易结晶析出,堵塞发动机的管道和过滤器而无法正常使用。如何降低生物柴油凝点和冷滤点成为生物柴油研究的一个十分重要的课题,本文综述了目前国内外改进生物柴油低温流动性能的研究进展,生物柴油降凝剂及其降凝机理研究。     

北方地区冬季输送0#柴油探讨

为解决低温环境柴油析蜡问题,满足北方地区冬季对0#柴油的迫切需求,从管输柴油的工艺运行分析、柴油析蜡特性实验研究和安全保障措施方面,提出了一套柴油低温输送方法,建立了0#柴油进线的关键控制指标,实现了冬季0#柴油的常态化运行。该技术已写入运行规程,在北方地区成品油管道推广应用,对进一步提高中石油在北方地区的市场占有率有意义。     

柴油低温流动改进剂感受性的影响因素

选择南阳柴油以及T1804、XLT-1808(103#)、PAE等几种柴油低温流动改进剂进行了感受性的实验研究.结果表明:不同的低温流动改进剂对同一种柴油感受性存在差别;存在差别的影响因素主要表现在低温流动改进剂的化学结构方面,如:分子结构、碳数分布、支链长度、极性基团、非极性基团;柴油中正构烷烃含量高使低温流动改进剂感受性变差.     

Low-temperature property and engine performance evaluation of ethyl and isopropyl esters of tallow and grease

Three monoalkyl fatty acid esters derived from tallow and grease were prepared by lipase-catalyzed transesterification and evaluated as prospective diesel engine fuels. The low-temperature properties of the esters, both neat and as 20% blends in No. 2 diesel fuel, were evaluated. Those properties included cloud point, pour point, cold filter plugging point, low-temperature flow test, and crystallization onset temperature. Other properties of the esters, such as kinematic viscosity, heating value, and calculated cetane number, also were determined. All three esters had acceptable physical and low-temperature properties, as well as acceptable fuel properties at the 20% level in diesel blends. Engine performance and emissions for the ester blends were determined in a direct-injection, matched two-cylinder diesel engine. Among the monoalkyl esters studied, ethyl greasate had better properties and engine performance characteristics than the two tallow esters. For the latter esters, isopropyl tallowate had better properties than ethyl tallowate. Presented in part at the 88th Annual Meeting of American Oil Chemists’ Society, Seattle, WA, May 1997.     

Low-temperature property and engine performance evaluation of ethyl and isopropyl esters of tallow and grease

Three monoalkyl fatty acid esters derived from tallow and grease were prepared by lipase-catalyzed transesterification and evaluated as prospective diesel engine fuels. The low-temperature properties of the esters, both neat and as 20% blends in No. 2 diesel fuel, were evaluated. Those properties included cloud point, pour point, cold filter plugging point, low-temperature flow test, and crystallization onset temperature. Other properties of the esters, such as kinematic viscosity, heating value, and calculated cetane number, also were determined. All three esters had acceptable physical and low-temperature properties, as well as acceptable fuel properties at the 20% level in diesel blends. Engine performance and emissions for the ester blends were determined in a direct-injection, matched two-cylinder diesel engine. Among the monoalkyl esters studied, ethyl greasate had better properties and engine performance characteristics than the two tallow esters. For the latter esters, isopropyl tallowate had better properties than ethyl tallowate. Presented in part at the 88th Annual Meeting of American Oil Chemists’ Society, Seattle, WA, May 1997.     

Partial hydrothermal oxidation of unsaturated high molecular weight carboxylic acids for enhancing the cold flow properties of biodiesel fuel

Biodiesel fuel has become more attractive recently because of its environmental benefits and the fact that it is a product made from renewable resources. However the less favorable cold flow properties or the low temperature operability of biodiesel fuel compared to conventional diesel is a major drawback limiting its use. The poor flow properties of biodiesel at cold temperatures are mainly due to biodiesel fuel being composed of long-chain fatty acids with an alcohol molecule attached. If the double bond of unsaturated fatty acids in these long-chain fatty acids could be ruptured selectively, then the cold flow properties of biodiesel fuel would be enhanced by reducing its viscosity.In this study, the selective hydrothermal oxidation of oleic acid, as a model compound of unsaturated high molecular weight carboxylic acids, was studied experimentally. The objective was to use this as a model to investigate whether the double bond of unsaturated fatty acids can be ruptured selectively by partial hydrothermal oxidation. Demonstration of this method could then be used to show the potential to improve the cold flow properties of biodiesel. Results showed that the amount of mono-carboxylic acids, aldehyde, di-carboxylic acids, and aldehyde-acids with a carbon number of 9 was significantly higher than other oxidative products. This suggests that the oxidative cleavage may principally occur at the double bond in hydrothermal conditions. The cloud and pour points for biodiesel fuel (B100) and B100 blend with a mixture of methyl esters or acetals were measured. These are the most important indicators for the cold flow properties of biodiesel fuel. The methyl esters or acetals used were made from the esterification of carboxylic acids or aldehydes by simulating the major oxidation products. These were obtained from the hydrothermal oxidation of oleic acid at different oxygen supply rates. Results showed that the cloud and pour points of the blend were significantly enhanced compared to those of B100.     

Effects of fatty acid derivatives on the ignition quality and cold flow of diesel fuel

The biodiesel that is considered as a possible substitute or extender of conventional automotive diesel fuel is commonly composed of fatty acid methyl esters that are prepared from the glycerides in vegetable oils by transesterification with methanol. This form of biodiesel is compatible with diesel fuel but offers no improvement in its ignition quality. This work describes the results of a series of experiments aimed at assessing other common fatty acid derivatives that could provide the desired biofuel component and, at the same time, improve the performance of the fuel. It was found that tertiary fatty amines and amides are significantly more effective than methyl esters in enhancing the ignition quality of the finished diesel fuel without having any negative effect on its cold flow properties.     

Computer Modeling System of the Industrial Diesel Fuel Catalytic Dewaxing Process

An unsteady mathematical model and a computer modeling system of the diesel fuel catalytic dewaxing process (mild hydrocracking) were developed. The modeling system allows for calculating the optimal technological mode to produce low‐freezing diesel fuel with the required cold filter plugging point taking into account the feedstock composition and catalyst activity. The modeling system consists of the main blocks: database, knowledge base, unsteady mathematical model of the diesel fuel catalytic dewaxing process, and application program package. Using the developed computer modeling system, the influence of the feedstock composition and flow rate as well as of the catalyst activity on the cold filter plugging point and the yield of diesel fuel is demonstrated.     

Physical and chemical properties of ethanol-diesel fuel blends

This paper discusses the physical-chemical properties of ethanol-diesel fuel blends. The attention is focused on the properties which influence the injection and engine characteristics significantly. Main properties have been investigated experimentally. The analysis of experimentally obtained fuel properties of tested fuels and their influence on engine characteristics are presented. Physical and chemical properties of diesel fuel and ethanol-diesel fuel blends were measured according to requirements and test methods for diesel fuel (EN590, 2003). The tested fuels were neat mineral diesel fuel (D100), 5% (v/v) ethanol/diesel fuel blend (E05D95), 10% (v/v) ethanol-diesel fuel blend (E10D90) and 15% (v/v) ethanol-diesel fuel blend (E15D85). It has been proved that, for ethanol-diesel fuel blends, some additives are necessary to keep stability under low temperature conditions. Also, cold weather properties test, such as cloud point and pour point tests are negatively affected by phase separation. The rest of the properties, excepting flash point, were within diesel fuel standard specifications. Based on this study, it can be concluded that using additives to avoid phase separation and to raise flash point, blends of diesel fuel with ethanol up to 15% can be used to fuel diesel engines if engine performance tests corroborate it.     

Thermal Evaluation of Diesel/Hydrogen Peroxide Fuel Blend

Thermal properties of fossil fuel are the key fundamental characteristics, which can distinguish any compound as a potential fuel. The performance of diesel fuel blend along with stability and solubility parameter designs are evaluated. The results from the experimental study indicate that the increase in hydrogen peroxide (H₂O₂) amount enhances the cetane number of diesel fuel blend significantly. However, the calorific value decreases as compared to pure diesel fuel. All values performed well according to the ASTM D‐975 diesel testing method. The thermodynamics of the prepared fuel blends also revealed that substantial solubility and diesel/H₂O₂ blend stability are provided even at lower temperatures. Such blends can be used as a feasible replacement of pure diesel fuel.     

生物柴油低温流动性改进方法研究进展

随着工业发展,人口增长,世界能源需求增加,石油资源却正面临枯竭的危机,在石油馏分油中消耗最大的柴油资源不可再生,生物柴油作为柴油替代燃料得到广泛发展,但其较差的低温流动性影响其在实际中使用,因此改善生物柴油低温流动性是一个亟需解决的问题。论述了生物柴油的低温流动性的评价指标和改进方法的研究进展。