Vegetable oil refining
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Vegetable oil can be used as feedstock for an oil refinery. There it can be transformed into fuel by hydrocracking (which breaks big molecules into smaller ones using hydrogen) or hydrogenation (which adds hydrogen to molecules). These methods can produce gasoline, diesel, and propane. Some commercial examples of vegetable oil refining are NExBTL, H-Bio, and the ConocoPhilips process. [1]
The majority of plant and animal oils are vegetable oils which are triglycerides and that is the type of oil these processes use. One type of algae, Botryococcus braunii produces a different type of oil, known as a triterpene, which is transformed into alkanes by a different process.
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[edit] Comparison to biodiesel
The normal method of making biodiesel is known as transesterification. It involves mixing vegetable oil, alcohol, and sodium hydroxide. This is simple enough that many people do it at home. [2] The reaction also produces glycerol as a product (~10% by weight). When refining vegetable oil no glycerol is produced, only fuels. Refined diesel is chemically identical to ideal diesel fuel, and does not have the problems specific to transesterified biodiesel. The cloud point can be adjusted to surpass petrodiesel, any blending ratio can be used, and no modifications or checks are required for any diesel engine.
[edit] Market
Germany expects to replace 3% of their diesel with fuel produced by refining vegetable oil by 2010. [3] Petrobras plans to use 256 million liters of vegetable oils in the production of H-Bio fuel in 2007. ConocoPhilips is processing 42,000 gallons per day. Neste Oil completed their first NExBTL plant in the summer 2007 and the second one will be completed in 2009. The annual production capacity of each these two plants will be 170,000 tons. [4]