BIODIESEL FUEL GLOSSARY

 

Aerosol - A dispersion of a liquid or solid in a gas.

 

Anhydrous- "Without water" - transesterification of biodiesel must be an anhydrous process or funny things hapen. Water in the vegetable oil causes either no reaction or cloudy biodiesel, and water in lye or methanol renders it less useful or even useless, depending on how much water is present. Either let your vegetable oil settle for 2-3 days before using and drain the water off the bottom, or heat the oil and boil off the water. Store lye and methanol in (separate) air-tight containers.

 

Biodiesel - "Biofuel" "McDiesel" - An environmentally safe, low polluting fuel for most diesel internal combustion and turbine engines. Can be mixed with petroleum fuel and stored anywhere petroleum is. Made from fresh or waste vegetable oils (triglycerides) that are a renewable energy source. Both commercially and privately made around the world. Relatively safe and easy to process when conscientiously approached. Benefits are substantially reduced engine emissions with as little as 20% biodiesel with 80%petroleum.

 

Biodiesel Recipe - The most common recipe uses waste vegetable oil (WVO), methanol (wood alcohol), and sodium hydroxide (caustic soda/lye) to produce biodiesel and glycerin. The most common steps are: (1) cleaning/heating WVO, (2) titration of WVO sample, (3) combining methanol and sodium hydroxide in exact amounts, (4) combining (3) with (1) and mixing at 50c, (5) settling (6) separating the biodiesel from the wastes, (7) washing and drying the biodiesel, (8) disposing of wastes.

 

Bubble Wash - A method of final washing of biodiesel through air agitation. Biodiesel floats above a quantity of water. Bubbles from an aquarium air pump and air stone are injected into the water causing the bubbles to rise. At the water/biodiesel interface, the air bubbles carry water up through the biodiesel by surface tension. Simple diffusion causes water soluble impurities in the biodiesel to be extracted into the water. As the bubble reaches the surface and breaks, the water is freed and percolates back down through the biodiesel again.

 

Canola- See Rape

 

Colloid - A stable system of small particles dispersed in something else. A multi-phase system in which one dimension of a dispersed phase is of colloidal size. Colloids are the liquid and solid forms of aerosols, foams, emulsions, and suspensions within the colloidal size class. Milk and smoke are both colloids.

 

Colloidal size - .001 micron to 1 micron in any dimension. Dispersions where the particle size is in this range are referred to as colloidal aerosols, colloidal emulsions, colloidal foams, or colloidal suspensions.

 

Dispersion - A stable or unstable system of fine particles, larger than colloidal size, evenly distributed in a medium.

 

Emulsification - to emulsify - to form an emulsion.

 

Emulsion - A suspension of small drops of 1 liquid in a 2nd with which the 1st will not mix. Emulsions can be formed either by mechanical agitation, or by chemical processes. Unstable emulsions will separate with time or temperature. Stable emulsions will not separate.

 

Esters - Any of a large group of organic compounds formed when an acid and alcohol is mixed. CH3COOCH3 (Methyl acetate) is the simplest ester. Biodiesel contains methyl stearate.

 

Ethanol - Ethyl alcohol - C2H5OH - CH3-CH2-OH. A good solvent.

 

Foam - A dispersion of a gas in a liquid or solid.

 

Glycerin - CH2-OH--CH-OH--CH2-OH. A byproduct of biodiesel production. Each of the "OH" sites is one of the three places where an ester is broken off of the triglyeride molecule (veg. oil).

 

KOH - Potassium Hydroxide. Used to make biodiesel from ethanol. A metallic base.

 

Lye - See NaOH

 

McDiesel - Promoting your biodiesel with this name may bring you a lawsuit. Used vegetable oil from McDonald's or other fast food chains is not what you want to use, anyway. If you're going the used route, you have enough problems filtering it and gettting the water out without worrying about your oil being solid at room temperature (McDonald's and other fast food places use the cheapest vegetable oil possible - a low-quality palm oil). Better to avoid McDonald's altogether (vegetarians - remember, even their fries have beef in them!) and check out the grease dumpsters behind small restuarants. Chinese restaurants usually have high quality veg. oil, and oil that was used to make doughnuts is the best! And smells good, too!

 

Methanol - Methyl Alcohol - CH3OH - Good solvent and a component of gasohol. Burned in top fuel eliminator dragsters and toy airplane engines. Lethal if consumed. Used to make methoxide in biodiesel production. Methanol absorbs water from the air, so keep the container closed tightly, and purchase methanol which is known to be dry (anhydrous) or is 99.9% pure.

 

Methoxide - Sodium Methoxide - Sodium Methylate - (CH3-O+ Na-). An organic salt, in pure form a white powder. In biodiesel production, "methoxide" is a product of mixing methanol and sodium hydroxide, yielding a solution of sodium methoxide in methanol, and a significant amount of heat. Sodium Methoxide in methanol is a liquid that kills nerve cells before you can feel the pain. Rinse with water and seek medical attention immediately. Also highly explosive. Making sodium methoxide is the most dangerous step when making biodiesel. Carefully consider the safety of the design of your equipment and workspace before producing, and wear protective clothing and a respirator when handling. Use immediately as methoxide loses reactive properties with time.

 

NaOH - Sodium Hydroxide, lye, caustic soda (Red Devil Drain Cleaner). A metallic base. Strongly alkaline and extremely corrosive. Mixing with fluids usually causes heat, and can create enough heat to ignite flammables (such as methanol), so add slowly. For biodiesel, this is one of the main reactants. Make sure you are purchasing "anhydrous sodium hydroxide." Anhydrous means it's dry, and water turns biodiesel into soap. Store this product in an airtight container to prevent NaOH from absorbing water and CO2 from the air. Store separately.

 

Optimal pH for Biodiesel - Seven. Neutral as distilled water (and most tap water).

 

pH - A measure of acidity and alkalinity of a solution on a scale with 7 representing neutrality. Lower numbers indicate increasing acidity, and higher numbers increasing alkalinity. Each unit of change represents a tenfold change in acidity or alkalinity. pH is mathematically found by taking the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity. The units are gram equivalents per liter of the solution.

 

Rape - Rape Seed - Rape Seed Oil - Food grade oil produced from rape seed is called Canola oil. Canola is a name taken from "Canada oil" due to the fact that much of the development of the oil was performed in Canada. Another early term for this oil is Colza. Makes good biodiesel.

 

Saponification - The reaction of an ester with a metallic base and water. The making of soap. This happens sometimes when you use too much lye in a biodiesel reaction... No worries - you can re-react the resulting top layer of unreacted liquid, and if you wish you can turn the semi-solid bottom layer into soap by adding more lye (make sure you know how much to add...).

 

Soy - Soy Oil, a vegetable oil pressed from soy beans.

 

Soy Diesel - A media term for biodiesel which accentuates the renewable nature of biodiesel. Popular in soy producing regions.

 

Suspension - A dispersion of a solid in a gas, liquid, or solid.

 

SVO - Straight Vegetable Oil. Burns well in many diesels, but does not start engine, and will coke in the injectors as a hot engine cools. A separate tank of petro diesel or biodiesel is often used during starting and stopping engine, and an electric valve allows transfer to the SVO tank. See links to SVO sites at the Maui Biodiesel main page.

 

Titration - Applied to biodiesel, titration is the act of determining the acidity of a sample of WVO by the dropwise addition of a known base to the sample while testing with pH paper for the desired neutral pH=7 reading. The amount of base needed to neutralize an amount of WVO determines how much base to add to the entire batch.

 

Transesterfication - Process of creating esters from vegetable oil (a triglyceride), and sodium methoxide. Products are Glycerin, Methyl Stearate, Methyl Oleate, Methyl Linoleate (assuming soy oil is used).

 

Viscosity - How a liquid is resistant to flow; "thickness" or "thinness". Methanol has a low viscosity, while vegetable oil has a high viscosity.

 

WVO - Waste Vegetable Oil. WVO is the usual starting product for the making of biodiesel. May be hot-water-washed for use as SVO.

 

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