Product category:
General lab equipment
News Release from: Labtex | Subject: Biodiesel testing
Edited by the Laboratorytalk Editorial
Team on 21 March 2006
Biodiesel fuel testing equipment
The properties of commercial biodiesel fuel depends upon the refining practices employed and the nature of the renewable lipids from which it is produced
Biodiesel can be produced from a variety of vegetable oils or animal fats which produce similar volatility characteristics and combustion emissions with varying cold flow properties There are a number of suggested standard test methods to be used in the development and QA of biodiesel fuel : Flash Point
This article was originally published on Laboratorytalk on 30 Sep 2005 at 8.00am (UK)
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The flash point for biodiesel is used as the mechanism to limit the level of unreacted alcohol remaining in the finished fuel.
The flash point is also of importance in connection with legal requirements and safety precautions involved in fuel handling and storage, and is normally specified to meet insurance and fire regulations.
Viscosity.
Further reading
Promoting Diehm glassware in UK and Ireland
Diehm manufactures glass reaction and distillation systems and plain or jacketed vessels in flat or round bottom designs with capacities to 100 litres and using standard Schott flanges up to DN450
Flash point testers from the original Mr Pensky
Fully automatic Pensky Martens flash point tester is pre-programmed with 14 standard test methods and user definable search programs for the examination of oils, fuels, lubricants and bitumens
Low temperature cooling to -180C
This method produces a coolant in the form of a gas stream with an exactly defined volume and temperature as it exits the heat exchanger
For some engines it may be advantageous to specify a minimum viscosity because of power loss due to injection pump and injector leakage.
Maximum allowable viscosity, on the other hand, is limited by considerations involved in engine design and size, and the characteristics of the injector system.
The upper limit for the viscosity of biodiesel (6.0 mm2/s at 40C) is higher than the maximum allowable viscosity in Specification D 975 Grad 2-D and 2-D low sulphur (4.1 mm/s at 40C).
Blending biodiesel with diesel fuel close to its upper limit could result in a biodiesel blend with viscosity above the upper limits contained in Specification D 975.
Sulphated Ash.
Ash-forming materials may be present in biodiesel in three forms: (1) abrasive solids, (2) soluble metallic soaps, and (3) unremoved catalysts.
Abrasive solids and unremoved catalysts can contribute to injector, fuel pump, piston and ring wear, and also to engine deposits.
Soluble metallic soaps have little effect on wear but may contribute to filter plugging and engine deposits.
Sulphur.
The effect of sulphur content on engine wear and deposits appears to vary considerably in importance and depends largely on operating conditions.
Fuel sulfur can also affect emissions control systems performance and various limits on sulfur have been imposed for environmental reasons.
Copper Strip Corrosion.
This test serves as a measure of possible difficulties with copper and brass or bronze parts of the fuel system.
The presence of acids or sulphur-containing compounds can tarnish the copper strip, thus indicating the possibility for corrosion.
Cetane Number.
Cetane number is a measure of the ignition quality of the fuel and influences white smoke and combustion roughness.
The cetane number requirements depend on engine design, size, nature of speed and load variations, and on starting and atmospherie conditions.
The calculated cetane index,Test Methods D 976 or D 4737, may not be used to approximate the cetane number with biodiesel or its blends.
There is not substantiating data to support the calculation of cetane index with biodiesel or biodiesel blends.
Cloud Point Cloud point is of importance in that it defines the temperature at which a cloud or haze of crystals appears in the fuel under prescribed test conditions which generally relates to the temperature at which crystals begin to precipitate from the fuel in use.The cloud point of biodiesel and its impact on the cold flow properties of the resulting blend should be monitored by the user to ensure trouble free operation in cold climates.
Carbon Residue Carbon residue gives a measure of the carbon depositing tendencies of a fuel oil.
While not directly correlating with engine deposits, this property is considered an approximation.
Although biodiesel is in the distillate boiling range, most biodiesel boils at approximately the same temperature and it is difficult to leave a 10% residual upon distillation.
Thus, a 100% sample is used to replace the 10% residual sample, with the calculation executed as if it were the 10% residual.
Acid Number.
The acid number is used to determine the level of free fatty acids or processing acids that may be present in biodiesel.
Biodiesel with a high acid number has been shown to increase fueling system deposits and may increase the likelihood for corrosion.
Acid number measures a different phenomenon for biodiesel than petrodiesel.
Increased recycle temperatures in new fuel system designs may increase filter plugging potential.
Free Glycerin.
The free glycerin method is used to determine the level of unbonded glycerin in the fuel.
High levels of free glycerin can cause injector deposits, as well as clogged fueling systems, and result in a buildup of free glycerin in the bottom of storage and fueling systems.
Total Glycerin.
The total glycerin method is used to determine the level of unbonded and bonded glycerin in the fuel.
Low levels of total glycerin ensure that high conversion of the oil or fat into its mono-alkyl esters has taken place.
High levels of mono-, di-, and triglycerides can cause intjector deposits and may adversely affect cold weather operation and filter plugging. Request a free brochure from Labtex ...
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