Club 80-90 Forums

Can anyone tell me if the sg on bio diesel is the same as normal derv.

Title: The Specific Gravity of Biodiesel and its Blend with Diesel Fuel
Author(s): Mustafa E. Tat and Jon Van Gerpen
Publication Date: Sep 1999
Summary:
The specific gravities of biodiesel and 75, 50, and 20% blends with No. 1 and No.2 diesel fuels were measured as a function of temperature from the onset of crystallization to 100 degrees C. The results indicate that biodiesel and its blends demonstrate temperature-dependent behavior that is qualitatively similar to the diesel fuels. The temperature dependence of the specific gravity for biodiesel and its blends was compared with the ASTM D 1250-80 procedure for the temperature correction of hydrocarbon fuels, and the procedure was found to provide accurate corrections. A blending equation was developed that allows the
specific gravity of blends to be calculated from the specific gravities of the
biodiesel and diesel fuels.
Copyright 2000 by AOCS Press, Paper Number 9143 in JAOCS 77, 115-119,
February 2000

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The Specific Gravity Of Biodiesel Fuels And Their Blends With Diesel Fuel
Wenqiao Yuan, Alan C. Hansen, Qin Zhang
Department of Agricultural and Biological Engineering, University of Illinois at Urbana-
Champaign, 360-AESB, 1304 West Pennsylvania Avenue, Urbana, IL 61801.
Phone: (217) 333-8595; Fax: (217) 244-0323; Email: wyuan@uiuc.edu
Abstract
The specific gravity of fuels is used as a precursor for a number of other fuel properties, such as heating value, viscosity and cetane number. Biodiesel fuel has significantly different properties than petroleum-derived diesel fuel. The objectives of this study were to investigate the relationship between the specific gravity and temperature of biodiesel
fuels and their blends with No.2 diesel fuel, and to determine whether the ASTM D1250 Petroleum Measurement Tables were applicable to these fuels. Also specific gravity data were provided as a reference for different biodiesel fuels and their blends with No.2 diesel fuel. The specific gravity of three biodiesel fuels, two soybean oil based methyl esters and a yellow grease methyl ester, and their 75, 50 and 25% blends with No.2 diesel
fuel were measured in the temperature range from about -5°C or from the onset of crystallization, to 100 °C. The measurements indicated that all the biodiesel fuels and their blends with No.2 diesel fuel had a linear specific gravity-temperature relationship similar to No.2 diesel fuel as expected. The specific gravities of the blends of biodiesel and No.2 diesel were found to be proportional to the mass fraction of the components.
This proportionality was used to estimate the specific gravities of the blends of biodiesel and diesel within 0.15% of measured data for all tested fuels from 0°C to 80°C. The estimated results for specific gravity from the ASTM D1250 Petroleum Measurement
Tables were compared to measured values and were found to be slightly overestimated at high temperatures while the prediction errors were less than 0.43% for all tested fuels from 0°C to 80°C

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I think, basically what they're saying is Yes, its what you would expect it to be based upon the fractionation components.

The graphs in the 2nd paper indicate that some bio-diesels have an s.g. upt o 5% greater than the D2 reference fuel.

You can find that pdf by using this Google search 'biodiesel specific gravity'

Many thanks

Biodiesel and SVO (straight Veg Oil).
Sources of SVO are not just palm oil, they are... oil seed rape (yello fields ) soyabean, sunflower, some types of algae, and recycled chip oil et al,
A recent survey in t'states found there was 4.5 Billion gallons of used veg oil available for recycling
and we scoff more chips than them

The other way to fuel a diesel engine with vegetable oil is to reduce the oil's viscosity before it gets into the tank and in this way, neither the engine or vehicle needs modification. Biodiesel is the name of a variety of ester-based oxygenated fuels made from vegetable oils or animal fats. A Methyl ester of vegetable oil or what we now call Biodiesel is very similar to normal petrochemical based diesel fuel.
Its viscosity is only twice that of diesel fuel and its molecular weight is roughly 1/3 of vegetable oil, hence it can be used as a straight petro-diesel replacement. This reduced viscosity vegetable oil is now called Biodiesel with a number of standards like the European EN 14214 standard and American ASTM standard defining exactly what the properties of that oil should be.

In the short term and until the diesel engine industry fits all engines with fuel heaters, Biodiesel might be the quickest way to drive the fuel's adoption and start displacing some of the petro diesel we use today.