E. Lois
National Technical University of Athens
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Featured researches published by E. Lois.
Biomass & Bioenergy | 2003
S. Kalligeros; F. Zannikos; S. Stournas; E. Lois; G. Anastopoulos; Ch Teas; F Sakellaropoulos
Vegetable oils are produced from numerous oil seed crops. While all vegetable oils have high-energy content, most require some processing to assure safe use in internal combustion engines. Some of these oils already have been evaluated as substitutes for diesel fuels. With the exception of rape seed oil which is the principal raw material for biodiesel fatty acid methyl esters, sunflower oil, corn oil and olive oil, which are abundant in Southern Europe, along with some wastes, such as used frying oils, appear to be attractive candidates for biodiesel production. In this paper, fuel consumption and exhaust emissions measurements from a single cylinder, stationary diesel engine are described. The engine was fueled with pure marine diesel fuel and blends containing two types of biodiesel, at proportions up to 50%. The two types of biodiesel appeared to have equal performance, and irrespective of the raw material used for their production, their addition to the marine diesel fuel improved the particulate matter, unburned hydrocarbons, nitrogen oxide and carbon monoxide emissions.
Desalination | 2001
C. Teas; S. Kalligeros; F. Zanikos; S. Stournas; E. Lois; Georgios Anastopoulos
The present study examines the absorption capacity of five different types of materials for oil spills clean up. The absorbents were a commercial cellulosic material from processed wood, a commercial synthetic organic fiber from polypropylene and three commercial types of local expanded perlite from the island of Milos. The absorption capacities of the above materials were evaluated in a wet as well as a dry environment with different types of petroleum products. The results showed that commercial types of perlite, in some cases, have absorption capacities comparable to natural and synthetic organic materials used for clean-up applications. The enhancement of the hydrophobic properties of perlite can result in better performance in a water bath. The nature of the spilled oil proved to play an important role in the selection of the proper absorbing material. Overall, the results suggested that partial substitution of commercial synthetic sorbents by mineral materials widely produced in Greece for oil spill clean-up operations is possible, given their friendliness to the environment and their local abundancy.
Fuel Processing Technology | 1995
F. Zannikos; E. Lois; S. Stournas
Abstract The known ability of several solvents to extract sulfur compounds selectivity from petroleum fractions can be dramatically improved by oxidizing the sulfur from the divalent state (sulfide) to the hexavalent (sulfone). The oxidation process itself leads to the removal of a substantial portion of the existing sulfur and makes the remaining sulfur compounds amenable to efficient removal even by solvents such as methanol which are not effective in selective extraction of the unoxidized sulfur compounds. Thus this combination process is capable of removing up to 90% of the sulfur compounds in petroleum fractions at acceptable yields. The oxidation process has no deleterious effects on the distillation profile and other characteristics of the middle distillate fractions that were examined.
Industrial Crops and Products | 2002
P.N. Giannelos; F. Zannikos; S. Stournas; E. Lois; G. Anastopoulos
Abstract Tobacco seed is a byproduct of tobacco leaves production in Greece. This oil seed was evaluated in the present study, as a renewable and potential source of energy. Successive tobacco seed oil extraction indicated that almost 38% of the seed was oil. The major constituents observed by GC analysis were linoleic acid (18:2), oleic acid (18:1) and palmitic acid (16:0). The physical, chemical and fuel related properties of tobacco seed oil were investigated in this work. These properties were comparable to those of other vegetable oils and to current European specifications for automotive diesel fuel. This study suggests that this non edible oil may be an appropriate substitute for diesel fuel. The environmental advantages of tobacco seed oil as a fuel can be exploited for specific niche markets such as inner city vehicles or tractors. On the other hand, tobacco seed oil as a fuel represents one possible hope for the future of EU tobacco agriculture.
Energy Conversion and Management | 2003
P. Arkoudeas; S. Kalligeros; F. Zannikos; G. Anastopoulos; Dimitrios Karonis; Dimitrios M. Korres; E. Lois
Abstract The first jet fuels were aviation gasoline (avgas), and the characteristics of subsequent jet fuels have evolved from this original choice, the available supply infrastructure, and the refiners’ capabilities. Earlier on, it was evident that avgas would have to be altered to operate satisfactorily in jet powered aircraft. The present contribution outlines the various requirements that led to development of various operational jet fuels, including United States Jet A (European Jet A-1), JP-4 (NATO code, F-40), JP-5 (NATO code, F-44), JP-7 (US only), JP-8 (F-34), JP-TS (US only), and JP-8+100. To reduce this fuel logistic burden, the NATO Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment. To this end, F-34 is replacing distillate Diesel fuel in many applications. In order to make this type of fuel compatible with direct injection compression engines, the Fuels and Lubricants Laboratory of the National Technical University of Athens, used a stationary Diesel engine fueled with fuel blends containing two different types of biodiesel, at proportions up to 50%. In this paper, fuel consumption and exhaust emission measurements from a single cylinder, stationary, Diesel engine are described. The two types of biodiesel appeared to have equal performance, and irrespective of the raw material used for their production, their addition to the JP-8 aviation fuel improved the particulate matter emissions.
Tribology International | 2001
G. Anastopoulos; E. Lois; F. Zannikos; S. Kalligeros; C. Teas
This paper presents the impact of acetoacetic esters and di-carboxylic acid esters on the lubrication properties of automotive diesel. Three alkyl acetoacetates and seven di-carboxylic esters were used as lubricating additives on two low sulfur diesel fuels, at seven different concentrations of 50, 100, 500, 750, 1000, 1500 and 2000 ppm. Tribological experiments carried out on the high frequency reciprocating rig (HFRR) showed that only two of the three acetoacetic esters used, provide satisfactory mean wear scar diameter (WS 1.4) of less than 460 μm, at the concentration level of 750 ppm. In the case of di-carboxylic acid esters, the effective concentration was 500 ppm or higher.
Journal of Engineering for Gas Turbines and Power-transactions of The Asme | 2000
A. Serdari; K. Fragioudakis; S. Kalligeros; S. Stournas; E. Lois
With the exception of rape seed oil which is the principal raw material for biodiesel Fatty Acid Methyl Esters, (FAME) production, sunflower oil, corn oil, and olive oil, which are abundant in Southern Europe, along with some wastes, such as used frying oils, appear to be attractive candidates for biodiesel production. In this paper fuel consumption and exhaust emission measurements from a single cylinder, stationary diesel engine are described, The engine was fueled with fuel blends containing four different types of biodiesel, at proportions up to 100 percent; the further impact of the usage of two specific additives was also investigated. The four types of biodiesel appeared to have equal performance and irrespective of the raw material used for their production, their addition to the traditional diesel fuel improved the particulate matter emissions, The results improve further when specific additive combinations are used.
Tribology International | 2002
G. Anastopoulos; E. Lois; F. Zannikos; S. Kalligeros; C. Teas
Abstract To reduce their fuel related logistic burden, NATO Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment. To this end, F-34 is replacing distillate diesel fuel in many applications. However, tests conducted with kerosene on High Frequency Reciprocating Rig, showed that it causes unacceptable wear due to the poor lubricity of aviation fuel. In order to make this type of fuel compatible with direct injection compression engines, tests were carried out with ten mono–carboxylic acid esters to improve the lubricity of kerosene. Tribological results showed that all esters tested, were suitable for increasing the kerosene lubricity to a satisfactory level. Among the esters of the same molecular type, those having the ester group around the middle of the molecule appear to have better lubrication performance.
Energy | 2003
S. Kalligeros; F. Zannikos; S. Stournas; E. Lois
The fuel adulteration problem is associated with environmental pollution, problems with engine performance, and tax losses. Here, results are presented of a survey in leaded gasoline and automotive diesel, obtained from service stations representative of all the oil companies operating in Greece. For this purpose, 165 samples of gasoline and 420 samples of automotive diesel were collected from various parts of the country during the years 1998, 1999, and 2000. The gasoline samples were subsequently analyzed for their key properties and for any adulteration with cheaper unleaded gasoline. Octane number, benzene, olefins, and total aromatics were determined with the mid-IR method, and the sulfur content with a UVF elemental analyzer. The analysis of the automotive diesel samples concerned some key properties such as the cetane index, density, sulfur content, and the distillation properties of the fuel. The results indicate that there is a large fluctuation of fuel properties among the oil marketers. Examination of the quinizarin content (the tracer of unleaded gasoline) has shown that 11 leaded gasoline samples (8.8%) were mixed with unleaded gasoline, 5 leaded gasoline samples (4%) were mixed with aromatic solvents, whereas about 28% of the automotive diesel samples suffered from some degree of adulteration, mainly with cheaper heating fuel; and one automotive diesel sample was adulterated with a lighter fraction. Fuel misuse is a common problem not only for European countries but for practically every nation in the world. The European Union recently expressed its concern on this issue, mandating that by the year 2002 all the member states will promote the development of a uniform system for fuel quality monitoring.
SAE transactions | 2004
Dimitrios M. Korres; E. Lois; Dimitrios Karonis
The present paper aims to discuss the quality characteristics of Jet Fuels used in the Greek market in comparison with fuels used in other countries and to evaluate jet fuels along with diesel and biodiesel on a diesel engine. To establish the quality characteristics for Jet Fuels of the Greek market, fuel samples were collected from the local refineries on a regular basis, thus monitoring the fuel quality fluctuation over time. JP8, along with diesel and biodiesel, were used alone and in mixtures on a single cylinder stationary diesel engine. Emissions and volumetric fuel consumption were measured under various loads.