Biodiesel
ATTENTION: You are using a browser that is out of date and not supported. Please note that the page may not display properly. It is recommended that you upgrade your browser to its most recent version.
Liquid fuels from low grade crops and farm wastes
The principle liquid fuels that can be produced from agricultural crops and wastes are alcohols (ethanol) and oils (biodiesel). The production and use of ethanol from agricultural crops and wastes is significantly more complex than biodiesel. Background information on ethanol production can be found elsewhere (http://www.greenfuels.org/). The current note is limited to the production of biodiesel.
Invented in the 1850's, the conversion of vegetable oils and waste vegetable oil products into a usable fuel, commonly referred to as biodiesel, was commercially developed in Europe in the early 1990's. Before the vegetable oils and waste vegetable oil products can be used as a fuel, they must be processed to make them less viscous, or sticky. Through a process called transesterification, the oils are blended with an alcohol - usually methanol, although ethanol can be used - and a catalyst such as sodium hydroxide. The resulting chemical reaction produces glycerin and an ester called biodiesel. An example of the process is represented by the following: 100kg of a fat or oil are reacted with 10kg or methanol (or ethanol) and a catalyst - this produces 10kg of glycerin and 100kg of biodiesel.
Biodiesel can be blended with conventional diesel fuel at any concentration. There are numerous blends ranging from pure biodiesel or B100 (i.e. 100% biodiesel) down to B1 (blend containing 1% biodiesel and 99% diesel). The blend level depends on economics, availability, the desired emissions level, material compatibility and combustion characteristics. Pure biodiesel (B100) must meet the American Standard for the Testing of Materials ASTM D6751 or the European EN-14214 specifications. There is also a Canadian standard for on-road vehicles using low blends such as B1 to B5: this is the Canadian General Standards Board specification CAN/CGSB-3.250 Automotive Low-Sulfur Diesel Fuel Containing Low Levels of Biodiesel Esters. These industry standards have been put in place to ensure the production process satisfies the following points: complete reaction and absence of free fatty acids, removal of glycerin, removal of catalyst, removal of alcohol, and low sulfur content. Only fuels produced that meet those criteria can truly be labeled biodiesel.
Another process called hydrotreating can also produce a petroleum fuel equivalent from biomass; often called renewable diesel, this fuel has properties even closer to those of diesel and usually meets or exceeds the fuel specifications in place. The process adapts conventional petroleum refining equipment to produce this material.
Production of biodiesel is well established in Europe, the US and South America (Brazil) however it remains an emerging sector in Canada where annual production is approximately 100 million liters. By comparison, the US production in 2006 was 945 million liters while European production was expected to reach 6,897 million liters that same year.
Use of biodiesel can apply to many sectors such as the transportation sector for on and off-road vehicles, rail, marine, mining and also the energy sector in the form of heat and/or power. The potential impacts of a biodiesel industry on the agriculture sector are substantial when considering the feedstocks required for biodiesel production. The biodiesel industry in Europe is mostly based on rapeseed oil, while in the US soybean is the crop of choice. Currently in Canada, yellow grease (recycled frying oils), soybean oil and distressed canola oil make up the majority of feedstocks.
Use on the farm is certainly possible, from machinery to heating systems to backup power generators, with no or very little modifications in most cases. That being said there are some technical issues to consider regarding the fuel; these will be discussed in the next section.
Modified: 04-03-2008
