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What is biodiesel? Biodiesel is a fuel similar to #2 diesel fuel that is made from the chemical breakdown of vegetable oil. It can be used as a straight fuel (100% biodiesel = B100) or mixed at any ratio with #2 diesel fuel (i.e. 20% biodiesel in diesel would be called B20). Green Technologies sells only B100 and cold-weather blends. Why should I use biodiesel? There are several advantages to using biodiesel and biodiesel blends:
What does "off-road" mean? "Off road" simply means that our fuel is not currently tested according to ASTM protocols, although we have developed our own batch testing. The purity of our fuel is about 95%- the major impurities are fatty acids and unreacted oil. ASTM-grade fuel is 98%. "Off-road" uses include heating oil, heavy machinery, maple syrup evaporators, diesel boat engines, generators and farm equipment. In addition, road taxes (currently about 50 cents/gallon) are not assessed, which results in savings for our customers. Because we only sell B100, our prices do not include the 50 cent blenders rebate either. For customers who want to use biodiesel on roads (i.e. car, truck or bus) we offer ASTM-grade biodiesel. This fuel is made from virgin oil and is imported from out of state. The price includes road taxes. How is biodiesel made? It is created in a process called transesterification. Green Technologies uses waste vegetable oil (WVO) as a starting material, but virgin oil (VO) can also be used. The oil is mixed at warm temperatures with methanol and potassium hydroxide. The oil molecules are broken into four pieces- three methyl esters (the biodiesel) and one glycerol molecule. These are then separated. The photo on the left is WVO-biodiesel (left) and VO-biodiesel (right). The color of the WVO product varies from batch to batch and is generally darker than VO-derived biodiesel. The photo on the right is the "glycerol layer" from a WVO reaction, which contains glycerol, water, some fatty acids, salts, excess methanol and the bulk of the burned bits from the WVO starting material.
What are the potential applications of biodiesel? Biodiesel can be used in any diesel engine. This includes generators, heavy equipment, buses, automobiles, boat engines, trucks and oil-burning home furnaces (home heating oil is actually #2 diesel fuel). Do I need to modify my engine to run biodiesel? No modifications to the engine are necessary at low biodiesel blends (less than B40). However, if you live in a very cold location, you may want to invest in heaters for the fuel system (see below). For blends over B40, we have found that certain rubber gaskets, hoses, and o-rings swell with constant biodiesel exposure, including the components of some fuel pumps. Please contact us for more information. How do I make the switch to biodiesel? If you plan to switch to B100 (100% biodiesel), it is recommended that you start with B5 (5%) and gradually increase the biodiesel concentration over a period of several months. The reasons are two-fold. First, biodiesel has strong solvent properties. It tends to dissolve material that has deposited inside the fuel system from the petroleum diesel fuel. Second, it allows you to optimize the diesel to biodiesel ratio for your weather conditions (see below). You should be aware that in the coldest months of the year, the biodiesel ratio will probably have to be decreased, unless you add strategic heating. Of course the reverse is also true- as the temperature rises, so can your biodiesel concentration. Are there any problems with biodiesel? The main problems that we have seen involve switching too quickly to a high biodiesel ratio. We have also encountered problems at low (below freezing) temperatures. Most problems can be reversed by heating the clogged part up to about 35o C (95o F). Filters will also have to be replaced often when higher biodiesel blends are used because particulate deposits in the system are released by biodiesel. Will biodiesel work in cold weather? Cold weather is definitely an issue here in northern Vermont, where temperatures routinely reach -20o F. Biodiesel is characterized by the cloud point (where microcrystals begin to form and nozzles begin to clog) and the pour or gel point (the point at which the fuel freezes solid). (more about cloud and gel points) Because our company makes biodiesel from waste vegetable oil, the cloud point of our newly synthesized fuel is relatively high. This is because of animal fat contaminants in the feedstock. We offer a line of antigel agents to help combat this problem, however we have only found them to be effective in the spring and fall (not in the coldest months of the year). Another option is to simply decrease the biodiesel ratio during the winter. For instance, B5 behaves identically to straight petroleum diesel fuel at low temperatures. One could also heat the entire fuel system, including the tank, supply lines and injectors. We supply several heating options. For more information http://en.wikipedia.org/wiki/Biodiesel Biodiesel in Vermont Biodiesel in the US
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Last Updated 5/2/06
Copyright 2006, Green Technologies, LLC
