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.
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.
This article examines the possibility of measuring lift maintenance through analysis of used hydraulic oil. Hydraulic oils have proved to be a reliable indicator for the maintenance performed on ...elevators. It has also been proved that the end users or the maintenance personnel do not always conform to the instructions of the elevators' hydraulic machine manufacturer. Furthermore, by examining the proportion of the metals, an estimation of the corrosion and the wear resistance of the joined moving parts can be observed. Additionally, the presence of chlorine and calcium in hydraulic oils demonstrates their function in a highly corrosive environment.
Investigation of the Natural Gas Quality in Greece Vourliotis, P.; Pallis, P.; Kalligeros, S. ...
Energy sources. Part A, Recovery, utilization, and environmental effects,
10/2015, Letnik:
37, Številka:
19
Journal Article
Recenzirano
Recently the European Commission started a project in order to harmonize the gas quality in the European Union. In 2007, a mandate was published to the European Committee for Standardization for ...drawing up standards for gas quality parameters for group H-gas. This mandate was in close relation with the Directive 2003/55/EC of the European Parliament. This article presents the results of a survey for the quality of the natural gas, which is distributed in Greece. Random samples were tested for 20 days and the main parameters were recorded and examined. The results indicate a significant fluctuation in the examined gas characteristics.
This paper presents the impact of oxygen and nitrogen compounds on the lubrication properties of low sulfur diesel fuels. It discusses the most recent results, concerning the influence of adding low ...amounts of 4 specific types of biodiesel, 5 aliphatic amines, 2 tertiarty amides, 10 mono-carboxylic acid esters, 3 acetoacetates and 7 esters of di-carboxylic acids on the tribological behaviour of the steel-on-steel systems, lubricated with low sulfur automotive diesel fuel. Experiments were carried out on the HFRR (high frequency reciprocating rig). The obtained wear results showed that all the various classes of additives improved fuel lubricity.
In this study, fatty acid ethyl esters (FAEE) were produced from four different vegetable oils (sunflower, cotton seed, olive oil, and used frying oil) using calcium ethoxide as a heterogeneous solid ...base catalyst. The ester preparation involved a two-step transesterification reaction, followed by purification. The effects of the mass ratio of catalyst to oil, the molar ratio of ethanol to oil, and the reaction temperature were studied on conversion of sunflower oil to optimize the reaction conditions in both stages. The rest of the vegetable oils were converted to ethyl esters under optimum reaction parameters. The optimal conditions for first stage transterification were an ethanol/oil molar ratio of 12:1, catalyst amount (3.5%), and 80°C temperature, whereas the maximum yield of ethyl esters reached 80.5%. In the second stage, the yield of ethyl esters showed signs of improvement of 16% in relation with the one-stage transesterification, which was obtained under the following optimal conditions: catalyst concentration 0.75% and ethanol/oil molar ratio 6:1. Property analysis of prepared ethyl ester samples was done, in order to examine their quality parameters. The results obtained showed that the density, viscosity, and calorific value of the produced ethyl esters had values close to those of a no. 2 diesel. On the contrary, the cold filter plugging points were higher than the conventional diesel fuel.
To reduce their fuel related logistic burden, North Atlantic Treaty Organization (NATO) Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment. To this end, F-34 ...(the commercial equivalent is Jet A-1) is replacing distillate diesel fuel in many applications. However, tests conducted with this kerosene type on high frequency reciprocating rig showed that this type of fuel causes unacceptable wear. This excessive wear is caused by the poor lubricity of aviation fuel. In order to make this type of fuel compatible with direct injection compression engines, seven di-carboxylic acid esters have tested to improve the lubricity of kerosene. Tribological results showed that all esters tested in this series of experiments seem to be suitable for increasing the kerosene lubricity to a satisfactory level.
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.
This work examines the production of briquettes for household use from biomass in combination with plastic materials from different sources. Additionally, the combustion characteristics of the ...briquettes in a common open fireplace were studied. It is clear that the geometry of the briquettes has no influence on the smoke emissions. When the briquettes have a small amount of polyethylene terephthalate (PET), the behavior in the combustion is steadier because of the increase of oxygen supply. The smoke levels are between the 3rd and 4th grades of the smoke number scale. Measuring the carbon monoxide emission, it was observed that the burning of the plastic in the mixture with biomass increases the carbon monoxide emissions from 10% to 30% as compared to carbon monoxide emission from sawdust biomass emissions which was used as a reference.
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.
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