Glossary of terms
Aerosol - A dispersion of a liquid or solid in a gas.
Acid esterification - A common approach for removing free fatty acids from the feedstock is via acid catalyzed esterification in the presence of methanol. This converts the free fatty acids to methyl esters (e.g., biodiesel). Acid esterification equipment requires the use of stainless steel equipment due to the corrosive nature of the process.
- 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 - An environmentally safe, low polluting fuel for most diesel internal combustion and turbine engines, containing methyl or ethyl esters made from fresh or waste vegetable oils (triglycerides).
Biodiesel Recipe - Like a recipe for making a cake, a biodiesel recipe specifies the ingredients required, and the steps for combining and processing them to make biodiesel fuel. The most common recipe uses waste vegetable oil (WVO), methanol (wood alcohol), and sodium hydroxide (caustic soda) to produce biodiesel and glycerine. 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) waiting for separation, (6) separating the biodiesel from the wastes, (7) washing and drying the biodiesel, (8) disposing of the wastes.
Bubble Wash - A method of final washing of biodiesel through air agitiation. 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 soluable 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.
Blending vegetable oils with petro diesel - A number of methods exist to blend vegetable oil with petro diesel and create a low viscosity fuel oil with similar properties to diesel. One such method results in a product called AGTANE and this is the result of mixing recycled Yellow Grease with hydrogen in the presence of steam, later blended with heavy diesel oil.
Canola - a trademarked hybrid of rape initially bred in Canada. Rape Seed Oil was produced in the 19th century as a source of a lubricant for steam engines, and the oil has a bitter taste due to high levels of acids. Canola has been bred to reduce the amount of acid, yielding a palatable oil. Canola = CANadian Oil Low Acid. (unverified)
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.
Cetane Number - Measure of fuel ignition characteristics. Like the octane number used for gasoline, the higher the value, the better the fuel performance. A higher cetane number correlates with improved combustion, improved cold starting, reduced noise, white smoke, HC, CO and particulate emissions particularly during early warm-up phase. The EPA uses this parameter as a measure of aromatic content in fuel. Typical Cetane numbers around the world are as follows: Europe: 43 - 57, average 50 U.S. lower, minimum 40, average 43.
Cloud point - The temperature at which the first wax crystals appear and a standardized ASTM test protocol is used to determine this temperature.
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 is typically .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...as in mixing oil and vinegar in a blender. voila: salad dressing.
Emulsion - a usually unstable dispersion of two liquids which do not normally mix (they are immiscible). Emulsions can be formed either by mechanical aggitation, or by chemical processes. Unstable emulstions will separate over time or temperature, stable emulsions will not separate.
Esters - a product of the reaction of acids (usually organic) and alcohols. ch3cooch3 - methyl acetate is the simplest ester. one of the oxygens has a double bond. you can replace the 'ch3' part on the right with more ch2 chunks, and you get other methyl esters, including biodiesel's methyl stearate. many of the esters smell good.
Ethanol - ethyl alcohol - c2h5oh - ch3-ch2-oh = the intoxicating stuff in beer, and a good solvent. "beer is proof that god loves us and wants us to be happy" :: ben franklin.
Foam - A dispersion of a gas in a liquid or solid.
Glycerine - A byproduct of biodiesel production: ch2-oh--ch-oh--ch2-oh each of the "oh" sites is one of the three places where an ester is broken off of the triglyeride molecule (veg. oil).
Gum Number - The measure of the tendency of a fuel to form gums via oxidation.
Iodine # - Standard natural oil assay to measure the degree of unsaturation (or the number of double bonds present) in vegetable oils and fats.
Kerosene - A thin oil distilled from petroleum or shale oil, used as a fuel for heating and cooking, in lamps, and as a denaturant for alcohol, diesel or WVO.
KOH - Potassium Hydroxide. used to make biodiesel from ethanol. a metallic base.
Lye - a quaint american term for NaOH - Sodium Hydroxide
Methanol - methyl alcohol - ch3oh - the stuff they burn in top fuel eliminator dragsters and toy airplane engines. a good solvent and a component of gasahol. lethal if consumed. In biodiesel production, methanol is used to make methoxide. 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. solvent or paint grade methanol may not be anhydrous, and you will run the risk of making soap.
Methoxide - a.k.a. sodium methoxide a.k.a. 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, seek medical attention immediately. also highly explosive. making sodium methoxide is the most dangerous step you deal with when making biodiesel. for this reason, you should carefully consider the safety of the design of your equipment and workspace before using, and you should wear protective clothing and a respirator when handling. you should also make only what you intend to use immediately.
NaOH - Lye, Sodium Hydroxide, Caustic Soda, a.k.a. 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 - 7 (seven)...neutral, same as distilled water (and most tap water).
pH - (mirriam - webster) a measure of acidity and alkalinity of a solution that is a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity and on which each unit of change represents a tenfold change in acidity or alkalinity and that is the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity in gram equivalents per liter of the solution; also : the condition represented by a pH number.
Pyrolysis - The Pyrolysis cracking vegetable oil method uses heat and pressure to change the nature of vegetable oil. The Pyrolysis refining process does produce reduced viscosity oil and an acceptable diesel fuel replacement.
Pour point - The temperature at which the fuel is no longer pumpable.
Rape - Rape Seed - Rape Seed Oil - a.k.a. Cole seed. A member of the Mustard family. Any of a number of crops grown for oil from the seeds. Canola is a member of this family. 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.
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.
Titration - as 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. by knowing how much base neutralizes an amount of WVO, we discern how much base to add to the entire batch.
Transesterfication - Process of creating esters from vegetable oil (a triglyceride), and sodium methoxide. Products are Glycerine, Methyl Stearate, Methyl Oleate, Methyl Linoleate. (assuming soy veg oil)
Viscosity - the "thickness" or "thinness" of a fluid. methanol is "thin", having a low viscosity, while vegetatable oil is "thick" having a high viscosity. (mirriam - webster) the ratio of the tangential frictional force per unit area to the velocity gradient perpendicular to the direction of flow of a liquid.
WVO - Waste Vegetable Oil - WVO is the usual starting product for the making of biodiesel.