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Energies, Volume 1, Issue 1 (June 2008), Pages 1-40

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Editorial

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Open AccessEditorial Distinguishability, Information and Useful Energies
Energies 2008, 1(1), 1-2; doi:10.3390/en1010001
Received: 1 April 2008 / Published: 7 April 2008
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Open AccessEditorial Energies and Policies
Energies 2008, 1(1), 38-40; doi:10.3390/en1010038
Received: 18 June 2008 / Published: 20 June 2008
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Research

Jump to: Editorial, Other

Open AccessArticle Waste Cooking Oil as an Alternate Feedstock for Biodiesel Production
Energies 2008, 1(1), 3-18; doi:10.3390/en1010003
Received: 27 March 2008 / Accepted: 9 April 2008 / Published: 10 April 2008
Cited by 104 | PDF Full-text (171 KB) | HTML Full-text | XML Full-text
Abstract
As crude oil price reach a new high, the need for developing alternate fuels has become acute. Alternate fuels should be economically attractive in order to compete with currently used fossil fuels. In this work, biodiesel (ethyl ester) was prepared from waste cooking
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As crude oil price reach a new high, the need for developing alternate fuels has become acute. Alternate fuels should be economically attractive in order to compete with currently used fossil fuels. In this work, biodiesel (ethyl ester) was prepared from waste cooking oil collected from a local restaurant in Halifax, Nova Scotia, Canada. Ethyl alcohol with sodium hydroxide as a catalyst was used for the transesterification process. The fatty acid composition of the final biodiesel esters was determined by gas chromatography. The biodiesel was characterized by its physical and fuel properties including density, viscosity, acid value, flash point, cloud point, pour point, cetane index, water and sediment content, total and free glycerin content, diglycerides and monoglycerides, phosphorus content and sulfur content according to ASTM standards. The viscosity of the biodiesel ethyl ester was found to be 5.03 mm2/sec at 40oC. The viscosity of waste cooking oil measured in room temperature (at 21° C) was 72 mm2/sec. From the tests, the flash point was found to be 164oC, the phosphorous content was 2 ppm, those of calcium and magnesium were 1 ppm combined, water and sediment was 0 %, sulfur content was 2 ppm, total acid number was 0.29 mgKOH/g, cetane index was 61, cloud point was -1oC and pour point was -16oC. Production of biodiesel from waste cooking oils for diesel substitute is particularly important because of the decreasing trend of economical oil reserves, environmental problems caused due to fossil fuel use and the high price of petroleum products in the international market. Full article
Open AccessArticle Effect of Temperature, Wettability and Relative Permeability on Oil Recovery from Oil-wet Chalk
Energies 2008, 1(1), 19-34; doi:10.3390/en1010019
Received: 23 April 2008 / Revised: 30 May 2008 / Accepted: 2 June 2008 / Published: 6 July 2008
Cited by 11 | PDF Full-text (205 KB) | HTML Full-text | XML Full-text
Abstract
It is customary, for convenience, to use relative permeability data produced at room temperature. This paper shows that this practice underestimates oil recovery rates and ultimate recovery from chalk rocks for high temperature reservoirs. Above a certain temperature (80°C in this work) a
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It is customary, for convenience, to use relative permeability data produced at room temperature. This paper shows that this practice underestimates oil recovery rates and ultimate recovery from chalk rocks for high temperature reservoirs. Above a certain temperature (80°C in this work) a reduction of oil recovery was observed. The reduction in oil recovery is reflected by the shift of relative permeability data towards more oil-wet at high temperature (tested here 130°C). However, both IFT and contact angle measurements indicate an increase in water wetness as temperature increases, which contradict the results obtained by relative permeability experiments. This phenomenon may be explained based on the total interaction potential, which basically consists of van der Waals attractive and short-range Born repulsive and double layer electrostatic forces. The fluid/rock interactions is shown to be dominated by the repulsive forces above 80°C, hence increase fine detachment enhancing oil trapping. In other words the indicated oil wetness by relative permeability is misleading. Full article
(This article belongs to the Special Issue Oil Recovery)

Other

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Open AccessOpinion Corn and Cellulosic Ethanol Cause Major Problems
Energies 2008, 1(1), 35-37; doi:10.3390/en1010035
Received: 6 June 2008 / Accepted: 16 June 2008 / Published: 17 June 2008
Cited by 10 | PDF Full-text (22 KB) | HTML Full-text | XML Full-text
Abstract Crops for biofuels squanders cropland, water, and energy resources vital for food production needed for people. Full article
(This article belongs to the Special Issue Energy Policy)

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