Glossary
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Alternative Fuel [top] - Sustainable, non-petroleum fuel with energy, security, and environmental benefits. Examples include methanol, denatured ethanol, natural gas, hydrogen, electricity from solar, hydro, or wind energy.
ASTM [top] - The American Society for Testing Materials is a non-profit organization that has created standards, referred to as ASTM specifications, for commercial biodiesel. ASTM's "Standard Specifications for Biodiesel Fuel (B100) Blending Stock for Distillation Fuels," D6751-02, includes results and measurable fuel qualities as well as testing methods.
Biodiesel [top] - Biodiesel is composed of monoalkyl esters (methyl/ethyl esters), a long chain of fatty acids derived from renewable lipid sources. It is an ester based, renewable fuel made from vegetable oils, recycled fryer oils, tallow and other biological products which have had their viscosity reduced using a process called tranestrification, by which glycerin (thick component of vegetable oil) is removed. Biodiesel is biodegradable, non-toxic, and essentially free of sulfur and aromatics. Originally biodiesel was considered a by-product of glycerin soap production.
Biodiesel Blend [top] - Blend of biodiesel and diesel fuels. The blend can be with Diesel #1, Diesel #2, or JP8. One standard blend that meets the minimum requirements of the federal EPAct clean air criteria is B20. The number after "B" indicates the percentage of biodiesel included in the blend. In B20, there would be 20% biodiesel and 80% diesel in the fuel blend. A biodiesel blend can come in any mixture percentage, i.e., B2, B5, B50, B85 and so on.
Biofuel [top] - Alcohols, esters, ethers, and other chemicals (biodiesel, ethanol, and methane) made from cellulosic biomass sources or organic matter (herbaceous and woody plants, animal fats, agricultural and forest waste, or municipal solid and industrial waste) within an active carbon cycle. Production and combustion of biofuels take and replenish the CO² in a circular, sustainable fashion. These fuels are used for stationary and mobile applications, i.e., electricity and transportation. Two commonly used biofuels are ethanol and biodiesel.
Biomass [top] - Plant material, vegetation, tallow and other animal fats, or other agricultural and forest wastes used as fuel or energy sources. Biomass also includes municipal solid and industrial wastes and crops grown solely for energy purposes.
B100 [top] - B100 indicates that the biodiesel is pure biodiesel since it is 100% biodiesel. See Biodiesel Blend for explanation of B and 100.
Cetane Number [top] - A measure of ignition quality of diesel fuel. The higher the cetane number, the easier the fuel ignites when it is injected into the engine.
Diesel #1 and Diesel #2 [top] - Diesel #1 is also called kerosene and is not generally used as a fuel oil in diesel vehicles. Diesel #1 has a lower viscosity (it is thinner) than Diesel #2. Diesel #2 is the typical diesel vehicle fuel. Biodiesel replaces Diesel #2 or a percentage.
Esters [top] - Methyl and ethyl esters produced from any vegetable (hemp, corn, soybean, sunflower) or tree (almond, walnut, palm, coconut) oils, animal fats (beef tallow), used oils (recycled fryer oils) or other fat sources from organic compounds. Esters are formed by combining an acid with an alcohol and eliminating the water. In the biodiesel reaction, esters are formed as a result of combining fatty acids and methanol or ethanol. See Transesterification.
Ethanol - Ethyl alcohol [top] - also known as "grain alcohol." Not commonly used in making biodiesel because of its low reactivity (higher quantity required) than menthanol. Usually made from corn as a by-product of the feed industry, but can be produced from numerous other feedstocks (i.e. hemp or artichoke). There is a lot of interest in commercial biodiesel from ethanol because it can be produced more sustainably. Today ethanol is blended with gasoline as an "extender" and "octane enhancer". E10 is 10% ethanol. Ethanol can replace more harmful gasoline additives such as MTBE.
Feedstock [top] - The source of the oil used to make biodiesel, commonly denoted as "_______methyl/ethyl esters." Rapeseed Methyl Esters (RME), Soy Methyl Esters (SME), and Fatty Acid Methyl Esters (FAME) are variants of biodiesel produced from different feedstocks.
Flashpoint [top] - The lowest temperature in °C at which a liquid will produce enough vapor to ignite, if the vapor is flammable. The lower the flashpoint, the higher the risk of fire. Biodiesel has an abnormally high flashpoint (for a fuel), making it very safe to handle and store. Where diesel #2's flashpoint is standardized at 60°-80° C, biodiesel's standard is 100°-170° C.
Fluorinated Polyethylene/Polypropylene [top] - Two types of plastic that have been specially modified to withstand certain chemicals, including biodiesel.
Fossil Fuel [top] - A hydrocarbon deposit, such as petroleum, coal, or natural gas, derived from living matter of a previous geologic time and used for fuel. Production and combustion of fossil fuels dump large amounts of CO² into the air that were not meant to be unearthed, resulting in a non-sustainable formation of the "Greenhouse Effect", which is destructive to all life on earth.
Glycerin [top] - The "thick" component of all biodiesel feedstocks. It is separated from the esters during the biodiesel reaction process, combining together with the catalyst to form glycerin soap, the by-product of making biodiesel. See Transesterification.
High Compression Ignition Engine [top] - Also know as a Diesel engine. Unlike gasoline engines which use a spark plug to ignite the fuel, there is no external ignition spark in a high compression engine. Air is compressed, driving its temperature up to a point that it ignites fuel which has been injected into the chamber.
Hydrocarbons [top] - Compounds containing various combinations of hydrogen and carbon atoms (see VOCs). Hydrocarbons contribute heavily to smog.
Lubricity [top] - The "smoothness" of a fuel which affects wear-and-tear on the engine. The higher the lubricity, the easier a fuel can move through an engine, resulting in longer engine life. Lubricity is measured as "kinetic viscosity." Biodiesel is known for its lubricity.
Methanol [top] - Methyl alcohol, also known as "wood alcohol," is commonly used in biodiesel for its reactivity. Generally, it is easier to find than ethanol. Sustainable methods of production are currently not economically viable. Usually, methyl alcohol is a by-product of the petroleum industry, and is often used as a "racing fuel."
Mutagenicity [top] - The property of chemical or physical agents inducing changes in genetic material that are transmitted during cell division. Fundamentally, a measure of cancer risk. The mutagenicity of biodiesel emissions is 75% - 90% less than its petroleum counterpart.
Nitrile [top] - Also called "Buna-N." Nitrile is a low grade rubber common in older vehicles' fuel systems and is not as ideal for use with biodiesel as the higher grade synthetics. For this reason, it is recommended that nitrile and natural rubber fuel system components be replaced with more suitable fluoropolymers.
NREL [top] - The National Renewable Energy Laboratory, responsible for our government's alternative fuel research. See www.nrel.gov.
Particulates [top] - Very small liquid and solid particles floating in the air. A component of smog.
Renewable Energy [top] - Designated commodity or resource, such as solar energy, biodiesel fuel, or firewood, that is inexhaustible or replaceable by new growth.
Silicon and Teflon [top] - Fluoropolymers that can withstand high heat, especially useful in replacing older rubber fuel lines.
Transesterification [top] - The process by which the vegetable oil molecule is "cracked" and the glycerin is removed, resulting in glycerin soap and methyl/ethyl esters (biodiesel). Organic fats and oils are triglycerides which are three hydrocarbon chains connected by glycerol. The bonds are broken hydrolyzing them to form free fatty acids. These fatty acids are then mixed or reacted with methanol or ethanol forming methyl or ethyl fatty acid esters. The mixture separates and settles out leaving the glycerin on the bottom and the methyl/ethyl ester or biodiesel on the top. The glycerin is then used for soap or any one of several hundred other products and the biodiesel is filtered and washed to be used as a fuel in a diesel engine.
Viton [top] - The most recommended fluoropolymer for replacing nitrile or natural rubber in older vehicles' fuel systems. It is very similar in functionality and appearance to rubber.
VOCs [top] - Stands for Volatile Organic Compounds. Carbon containing compounds that evaporate into the air (see hydrocarbons). VOCs are a major component of air pollution, and are beginning to receive public attention as more and more products labeled "Low VOCs" hit the market.