Möglichkeiten der Verwendung von Pflanzenöl als Kraftstoff für Dieselmotoren

Potential of Vegetable Oil as a Fuel for Diesel Engines Vegetable oils seem, not only under agricultural aspects, to be an alternative fuel because of their properties similar to Diesel fuel. For such renewable resources there exists principally an almost closed and also fast CO₂-cycle. For the time being rape oil methyl ester which will not be competitive from the economical point of view in a medium term range is predominantly used in small scale projects. The less expensive raw rape oil can only be used in special Diesel engines which was the result of special investigations carried out on behalf of the Federal Ministry for Research and Technology. There are only small advantages in the emission of air pollutants of vegetable oil engines at the place of operation. Because of the limited availability of vegetable oils there is only a limited potential for the substitution of Diesel fuel. Under long term aspects such bio fuels can contribute, however, to a substitution of the limited crude oil resources.     

Emulsification of Chemically Modified Vegetable Oils for Lubricant Use

Oil in water emulsions of several vegetable oils were studied in order to prepare a useful lubrication fluid. Several previously uncharacterized systems were studied in this paper, including those made from epoxidized vegetable oils. A series of different surfactants were studied in order to obtain emulsions suitable for lubrication applications. The epoxidized oils were found to form stable oil in water emulsions using several different surfactant systems. Only the (4) lauryl ether dodecyl polyethoxylated nonionic surfactant and a modified palm stearin methoxy ester ethoxylate were able to stabilize ordinary soybean oil for 1 week under our test conditions. Overall, the best surfactants were those with an HLB value slightly above 9. The droplet size of emulsions made with surfactants formed submicron droplets, whereas only droplets of larger diameter were obtained when surfactants were not added. Most importantly, a lubrication study was performed showing that even a 1% emulsion of the vegetable oils used in this study can reduce friction nearly as well as using the base oil alone.     

The effects of vegetable oil properties on injection and combustion in two different diesel engines

Four different vegetable oils, each in at least 3 different stages of processing, have been characterized according to their physical and chemical properties, their injection and atomization characteristics, and their performance and combustion characteristics in both a direct-injection and an indirect-injection diesel engine. The injection and atomization characteristics of the vegetable oils are significantly different than those of petroleum-derived diesel fuels, mainly as the result of their high viscosities. Heating the oils, however, results in spray characteristics more like those observed with diesel fuel. The 2 engine types demonstrated different sensitivities to the composition of the various oils. The combustion characteristics and the durability of the direct-injection engine were affected by the oil composition. The indirect-injection engine, however, was not greatly affected by composition. Two different preliminary specifications have been proposed: a stringent specification including compositional requirements for direct-injection engines, and a less stringent specification for indirect-injection engines. The specifications are discussed in terms of the data and the rationale used in their development. Some precautions concerning the application of the specifications are also presented. Presented at the AOCS Annual Meeting in Chicago, May 1983.     

Oleochemicals as a fuel: Mechanical and economic feasibility

The status of vegetable oils as diesel fuel substitutes is currently dubious. Although it is fair to consider them as short-term emergency fuels (or, more desirably, low proportion supplements to diesel fuels), they present mechanical problems in long-term use that have not yet been solved. It is preferable to use these oils blended in small proportions with diesel fuels. Indirect-injection diesel engines have had fewer problems than direct-injection engines, whether the tests were performed with pure vegetable oil fuel or with vegetable oil/diesel fuel blends. The economic prospect for these fuels is not promising. In general, they are not and have not been economical alternatives to diesel fuel. Exceptions appear to have occurred recently in Brazil and the Philippines where low local prices for vegetable oils combined with high petroleum prices encouraged officials to use low proportion vegetable oil/diesel fuel blends. Nonetheless, current and long-term trends in petroleum and oilseed prices indicate that these fuels will probably not be price competitive within the near future. Emergency disruption of petroleum supplies completely changes the economic situation. Vegetable oils would be worth much more as a fuel during disruptions than otherwise; thus incentives could be strong to include these oils in the fuel supply, diverting them from the food supply.     

Winter rape oil fuel for diesel engines: Recovery and utilization

Although vegetable oil cannot yet be recommended as a fuel for general use, considerable progress in recovery and use of rapeseed oil (Brassica napus L.) for diesel operation has been made. Operation of a small-scale screwpress plant (40 kg/hr) was demonstrated. Maintenance of screw and end rings was a major problem. The plant has operated with a recovery efficiency of 77% and has processed 10,100 kg of seed in 230 hr. High viscosity of the rapeseed oil and its tendency to polymerize within the cylinder were major chemical and physical problems encountered. Attempts to reduce the viscosity of the vegetable oil by preheating the fuel were not successful in sufficiently increasing the temperature of the fuel at the injector to be of value. Short-term engine performance with vegetable oils as a fuel in any proportion show power output and fuel consumption to be equivalent to the diesel-fueled engines. Severe engine damage occurred in a very short time period in tests of maximum power with varying engine rpm. Additional torque tests with all blends need to be conducted. A blend of 70/30 winter rape and No. 1 diesel has been used successfully to power a small single-cylinder diesel engine for 850 hr. No adverse wear, effect on lubricating oil or effect on power output were noted. Approved as Paper No. 8237 of the Idaho Agricultural Experiment Station.     

Evaluation of Methyl Esters of Mahua Oil (<Emphasis Type="Italic">Madhuca Indica</Emphasis>) as Diesel Fuel

There is increasing interest in India for suitable alternative fuels that are environment friendly. This search has led to mahua oil (MO) as one alternative for diesel fuel in India. Mahua oil methyl esters (MOME) were prepared by transesterification using potassium hydroxide (KOH) as catalyst and nuclear magnetic resonance (NMR) testing was done to determine the conversion of vegetable oil to biodiesel (MOME). The properties of MOME were close to those of diesel oil. Engine testing was conducted using a single-cylinder 4-stroke direct-injection, constant-speed compression-ignition diesel engine using MO, MOME and B20 as fuels. The engine ran smoothly with MOME and B20, but heavy smoke emissions were observed when MO was used as fuel.     

环氧植物油基增塑剂的发展状况

介绍了无毒、环保型增塑剂环氧植物油的制备原理、方法,以及环氧化过程中的影响因素如反应时间、有机酸和氧化剂的配比、反应温度、双氧水浓度等。简述了国内植物油的环氧化工艺的发展状况,重点讨论了国外先进的植物油环氧化催化工艺。     

Die wirkungsweise der viskositätsindex-verbesserer

One of the major reasons for using polymeric additives is to obtain a product which has better viscosity-temperature characteristics than a comparable pure mineral oil. Extensive measurements of the viscosity-temperature behaviour of motor oils with and without polymer addition show the necessity of a revision of the generally accepted concept of the mechanism of viscosity index improvement. By addition of polymer the better viscosity-temperature characteristics of light oils, which are however of very limited value for lubrication of engines because of their low viscosity at high temperatures, can be maintained partially in the range of higher viscosities. So it becomes obvious how it is possible to produce multigrade oils both from polymers the polymer coil dimensions of which expand, as well as from polymers, the polymer coils of which contract with increasing temperature. In fact, coil expansion promotes viscosity index improvement to some extent but in no way does this effect play a decisive part.     

植物油改性技术及在醋纤纺丝油剂中应用

文章综述了天然植物油改性及其衍生物产品开发研究与在化纤纺丝油剂领域应用现状,介绍了植物油深度改性获得的脂肪酸乳酸酯和氢化植物油产品在醋纤工业纺丝油剂中的替代矿物油的应用研究,用作内油时浆液粘度下降,用作外油时纺丝断头率略有下降,并对环境友好的植物油基产品在化纤领域的应用研究进行了展望。     

Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil

One of the major difficulties in using crude vegetable oils as substitute fuels in diesel engines is their relatively high viscosities. Increasing the temperature of the crude vegetable oil, blending it with diesel oil, or the combination of both offers a simple and effective means of controlling and lowering the viscosities of vegetable oils. This work reports viscosity data, determined with a rotational bob-and-cup viscometer, for crude palm oil and cononut oil blended with diesel oil over the temperature range of 20–80°C and for different mixture compositions. All the test oil samples showed a time-independent newtonian type of flow behavior. The reduction of viscosity with increasing liquid temperature followed an exponential relationship, with the two constants of the equation being a function of the volume percentage of the vegetable oil in the mixture. A single empirical equation was developed for predicting the viscosity of these fuel mixtures under varying temperatures and blend compositions.     

Friction properties of vegetable oils

Vegetable oils are a renewable and an environmentally friendly alternative to petroleum-based oils in lubrication and other important application areas. Vegetable oils fall into two broad chemical categories: triesters (or TG) and monoesters. Most vegetable oils are triesters of glycerol with FA, whose characteristics are dependent on the chemistry and composition of the FA residues. A small percentage of vegetable oils are monoesters of long-chain FA and fatty alcohols of varying chemistries. In this work, the free energy of adsorption (ΔG _ads) of safflower (SA), high-oleic safflower (HOSA), and jojoba (JO), methyl oleate (MO), and methyl palmitate (MP) on steel were investigated. SA and HOSA are TG of vegetable oils with FA residues of radically different degrees of unsaturation. JO is a monoester vegetable oil. ΔG _ads is one of the major factors affecting the boundary friction properties of lubricant ingredients. ΔG _ads was found to increase in the order: HOSA≤SA<JO<MO≤MP. The results are consistent with the degree of functionality and other chemical properties of the oils studied.     

Flow properties of vegetable oil-diesel fuel blends

Straight vegetable oils provide cleaner burning and renewable alternatives to diesel fuel, but their inherently high viscosity compared to petroleum based diesel is undesirable for diesel engines. Lowering the viscosity can be simply achieved by either increasing the temperature of the oil or by blending it with diesel fuel, or both. In this work the rheological properties of diesel fuel and vegetable oil mixtures at different compositions were studied as a function of temperature to determine a viscosity-temperature-composition relationship for use in design and optimization of heating and fuel injection systems used in diesel engines. The vegetable oils used were corn, canola, olive, peanut, soybean and sunflower oils which are of commercial food grade. All the vegetable oils and their blends with No. 2 diesel fuel showed time-independent Newtonian behaviour within the test temperatures between 20 °C and 80 °C. Viscosities of the pure oils and diesel were satisfactorily correlated with temperature by means of the Arrhenius typed relationship. The Arrhenius blending rule was found applicable to describing the composition dependence of viscosity all vegetable oils-diesel blends at a fixed temperature. These relations were combined to develop a simple mixture viscosity model to predict the viscosity of the vegetable oil-diesel blends as functions of temperature and composition based on properties of the pure components.     

Umweltrelevante Kriterien zur Anwendung von Pflanzenölen und deren Derivaten im Schmierstoffbereich

Environmental criteria for the use of vegetable oils and their derivates in lubricants The motive behind the use of harvestable raw materials and their derivates in lubricants is their extraordinary environmental compatibility, and the substitution of mineral oil with biodegradable base oils is a primary objective. In the meantime, environmentally friendly, biodegradable alternatives are available for almost all mineral oil-based lubricants. In 1997, about 40000 tons of rapidly biodegradable lubricants were sold in Germany alone, about 4.5% of total lubricant consumption. An increase in this share is the aim of various measures taken by governments and authorities. In general, it is accepted that potentially more than 90% of all lubricants could be manufactured from harvestable raw materials.     

Experimental study of the effects of vegetable oil methyl ester on DI diesel engine performance characteristics and pollutant emissions

Vegetable oil methyl ester (VOME) is produced through the transesterification of vegetable oil and can be used as biodiesel in diesel engines as a renewable, nontoxic, and potentially environmentally friendly fossil fuel alternative in light of growing concerns regarding global warming and increasing oil prices. This study used VOME fuels produced from eight commonly seen oil bases to conduct a series of engine tests to investigate the effects of VOME on the engine performance, exhaust emissions, and combustion characteristics. The experimental results showed that using VOME in an unmodified direct injection (DI) diesel engine yielded a higher brake specific fuel consumption (BSFC) due to the VOME fuel’s lower calorific value. The high cetane number of VOME also imparted a better ignition quality and the high intrinsic oxygen content advanced the combustion process. The earlier start of combustion and the rapid combustion rate led to a drastic increase in the heat release rate (HRR) and the in-cylinder combustion pressure (ICCP) during the premixed combustion phase. A higher combustion rate resulted in higher peaks of HRR and ICCP as well as near the top dead center (TDC) position. Thus, it was found that a diesel engine fueled with VOME could potentially produce the same engine power as one fueled with petroleum diesel (PD), but with a reduction in the exhaust gas temperature (EGT), smoke and total hydrocarbon (THC) emissions, albeit with a slight increase in nitrogen oxides (NO_x) emissions. In addition, the VOME which possesses shorter carbon chains, more saturated bonds, and a higher oxygen content also yields a lower EGT as well as reduced smoke, NO_x, and THC emissions. However, this is obtained at the detriment of an increased BSFC.     

Detection of adulteration of sesame and peanut oils via volatiles by GC × GC–TOF/MS coupled with principal components analysis and cluster analysis

The method of headspace coupled with comprehensive two‐dimensional GC–time‐of‐flight MS (HS‐GC × GC–TOF/MS) was applied to differentiate the volatile flavor compounds of three types of pure vegetable oils (sesame oils, peanut oils, and soybean oils) and two types of adulterated oils (sesame oils and peanut oils adulterated with soybean oils). Thirty common volatiles, 14 particular flavors and two particular flavors were identified from the three types of pure oils, from the sesame oils, and from the soybean oils, respectively. Thirty‐one potential markers (variables), which are crucial to the forming of different vegetable oil flavors, were selected from volatiles in different pure and adulterated oils, and they were analyzed using the principal component analysis (PCA) and cluster analysis (CA) approaches. The samples of three types of pure vegetable oil were completely classified using the PCA and CA. In addition, minimum adulteration levels of 5 and 10% can be differentiated in the adulteration of peanut oils and sesame oils with soybean oils, respectively. Practical applications: The objective was to develop one kind of potential differentiated method to distinguish high cost vegetable oils from lower grade and cheaper oils of poorer quality such as soybean oils. The test result in this article is satisfactory in discriminating adulterated oils from pure vegetable oils, and the test method is proved to be effective in analyzing different compounds. Furthermore, the method can also be used to detect other adulterants such as hazelnut oil and rapeseed oil. The method is an important technical support for public health against profit‐driven illegal activities.     

Emission Reduction of Regenerative Fuel Powered Co-Generation Plants with SCR- and Oxidation-Catalysts

Since the beginning of combustion engine development in this recent century various different fuels have been successfully tested. Diesel engines have been adapted to fuels made from mineral oils because of the rising importance and the cheapness in comparison to other fuels. On the other hand, it is possible to burn regenerative fuels in engines and achieve some significant advantages in comparison to fossil diesel fuel. This is, for example, a closed carbon dioxide (CO₂) cycle which causes no green house effect. It is possible to extract oil from various seeds like rapeseed. It is also possible to burn used oil from the food processing industry or waste grease and oil from food recycling companies. The great advantages: (1) food recycling oils can produce energy instead of use as animal food, and (2) as nobody knows exactly the consistency of the collected oils, poisonous pollution is possible. These regenerative fuels can be burned without any further processing in special adapted diesel engines, for example an Elsbett engine, or in precombustion engines with large swept volumes. Most researchers focused on operating diesel engines with regenerative fuels and reducing the emissions caring only about regulated exhaust components. In comparison to these studies it is necessary to learn more about the emissions beyond the exhaust regulations. Additionally emission reduction is possible by using an SCR-catalyst (selective catalytic reduction) to reduce the NO₂ combined with an oxidation-catalyst which reduces any kind of oxidisable emissions. The TU München, Lehrstuhl für Energie- und Umwelttechnik der Lebensmittelindustrie, operates a small co-generation plant with the ability of analysing the standard emission components (CO, NO₂, HC, particles, CO₂, O₂) and unregulated components (SO₂, NH₃, polycyclic aromatic hydrocarbons (PAH), aldehyde, ketone). The emissions show some significant differences in comparison to fossil diesel fuel which is caused by the diversity of each fuel. Results of an investigation on four different fuels (wastefat methyl ester (WME), rapeseed methyl ester (RME), rapeseed oil and diesel fuel) burned in a small co-generation plant with a SCR- and oxidation-catalyst will be presented. A comparison to the emissions before and after the catalysts will be shown additionally to the results of the different reduction potential of diesel fuel, methyl ester or untreated oils. The combination of regenerative fuel and catalyst shows good potential for reducing the emissions. Furthermore the use of regenerative fuels is a sustainable production of energy with an overall efficiency of almost 90%. Regenerative fuels based on vegetable oils and waste fat are a valuable form of energy and have some significant advantages in comparison to diesel fuel, like an almost closed carbon dioxide cycle, rapid biological decomposition and lower CO, HC and particle emissions. Regenerative fuels should also meet minimum standards discussed in the paper to avoid the risk of engine damage and to reduce emissions.     

Enzymatische Phosphatidentfernung aus Pflanzenölen

The Enzyme-Catalyzed Degumming Process of Vegetable Oils The new degumming process EnzyMax is the first to use a natural enzyme as a biocatalyst for phosphatide removal from vegetable oils. The enzyme Phospholipase A2 splits off the fatty acid linked in the sn-2 position of the phospholipid molecule thus imparting oil-insolubility to the remaining 1-acyl-lysophospholipid and making it amenable to separation. The EnzyMax degumming process can be used on all kinds of oil seed and varying oil qualities with consistently good performance. Even the addition of small enzyme amounts of abt. 700 lecitase units per kg of oil reduces the residual phosphorus concentration to below 10 ppm. As a result, chemical refining can be replaced by physical refining thus eliminating the need for neutralization, soapstock splitting and waste water treatment.     

The production of fatty acid isopropyl esters and their use as a diesel engine fuel

Biodiesel is an alternative fuel for diesel engines that consists of the monoalkyl esters of vegetable oils or animal fats. Currently, most biodiesel consists of methyl esters, which have poor cold-flow properties. Methyl esters of soybean oil will crystallize and plug fuel filters and lines at about 0°C. However, isopropyl esters have better cold-flow properties than methyl esters. This paper describes the production of isopropyl esters and their evaluation in a diesel engine. The effects of the alcohol amount, the catalyst amount, and two different catalysts on producing quality biodiesel were studied. Both sodium isopropoxide and potassium isopropoxide were found to be suitable for use in the transesterification process. A 20∶1 alcohol/TG molar ratio and a catalyst amount equal to 1% by weight (based on the TG amount) of sodium metal was the most cost-effective way to produce biodiesel fuel. The emissions from a diesel engine running on isopropyl esters made from soybean oil and yellow grease were investigated by comparing them with No. 2 diesel fuel and methyl esters. For nitrogen oxide emission, the difference between the biodiesel produced from soybean oil and yellow grease was greater than the difference between the methyl and isopropyl esters of both feedstocks. The other emissions from using isopropyl esters were about 50% lower in hydrocarbons, 10–20% lower in carbon monoxide, and 40% lower in smoke number when compared with No. 2 diesel fuel.     

Über den Einfluß von Licht auf den oxydativen Verderb von Speiseölen V: Reaktionskinetik

Influence of Light on the Oxidative Deterioration of Edible Oils V: Kinetics of Reaction A time law for the photochemical oxidation without the decomposition of hydroperoxides has been derived from the radical chain mechanism in the oxidation of edible oils. Quantum yield of the photochemical start reaction and of the chain length can be calculated from the experimental results for soybean oil in the first phase. Using these kinetic values as well as from the quantum yield of the brutto reaction it is proven that the first phase in the autoxidation of soybean oil does not proceed by autocatalysis. Autocatalytic oxidations, e. g. soybean oil in the second phase, sunflower oil, and peanut oil, are discussed on the basis of investigations on the oxidation rate as a function of absorbed quantum current. It is found that owing to the presence of antioxidants, the degree of unsaturation of oils alone is not responsible for the readiness with which the oil is oxidized.     

Canola and high erucic rapeseed oil as substitutes for diesel fuel: Preliminary tests

A cooperative project using the facilities of the POS Pilot Plant Corporation, the Saskatchewan Research Council and the Agricultural Engineering Department, University of Saskatchewan, and funded by Agriculture Canada, was initiated in 1980 to investigate the feasibility of using canola and high erucic rapeseed oil as a replacement/extender to diesel fuel in direct-injection diesel engines. Work carried out included the documented production and refining of canola and R500 (high erucic) vegetable oils, preparation of methyl ester and of blends of all these fuels with methanol and ethanol. These fuels were evaluated by ASTM and improvised tests to determine their usefulness as diesel fuel. Engine tests involved a 2-cylinder Petter diesel and a 6-cylinder John Deere turbocharged diesel. Results were similar for both engines in short-term performance tests, and indicated that: (a) maximal power was essentially the same when burning canola oil as when burning diesel fuel; (b) specific fuel consumption was ca. 6% higher when burning canola oil, but because canola oil has a heating value 14% less than diesel fuel, the thermal efficiency is somewhat higher when operating on canola oil; (c) there were no starting problems down to 10 C; (d) there were fewer particulates in the exhaust when burning canola oil; and (e) there was generally less combustion noise when burning canola oil. The high viscosity of canola oil (ca. 35 times that of disel fuel at 20 C) poses a major problem in using the oil at low temperature. Blending with diesel fuel and the creation of a methyl ester from the canola oil both proved effective in reducing viscosity, but neither lowered the pour point apprecibly. Efforts on reduction of pour points and further work on blends and on heating the fuel are described.