By Zach Pociask and Javaun Crane-Bonnell
By Zach Pociask and Javaun Crane-Bonnell

Biodiesel Background

Biodiesel is a renewable fuel created for diesel engines that is produced using natural oils such as animal fats, soy bean oil or other vegetable oils. It’s made up mono-alkyl esters of long fatty chain acids and is produced using a chemical process that removes glycerin from the triglyceride fat or oil. When produced it contains an alcohol such as methanol or ethanol to serve as a catalyst to yield the mono-alkyl esters. Biodiesel doesn't contain any petroleum yet it can be combined in any concentration with petroleum based diesel fuel to create a new mixture and can be used in regular diesel engines with little or even no modification.[1]

Chemistry used in Biodiesel production
This is the first reaction in the biodiesel production process.
This is the first reaction in the biodiesel production process.

The most economical way to produce biodiesel is through base catalyzed transesterification because it requires only low temperatures and pressures for production and yields a 98% energy conversion. In the transesterification process reaction a triglyceride reacts with an alcohol to form esters and alcohol. Triglycerides have a single glycerine molecule at their base attached to three long fatty acid chains, which affect the characteristics of the fat/oil and also the characteristics of the biodiesel. The triglyceride reacts with alcohol (methanol or ethanol in most cases) in the presence of a catalyst, usually a strong alkaline such as sodium hydroxide. Because the reaction between the fat or oil and the alcohol is a reversible reaction, the alcohol must be added in excess to make sure the reactants go through a complete conversion.[2]

The alcohol and fatty acids react to produce the mono-alkyl ester (biodiesel) and glycerin. If methanol was used, the product would be methyl esters, and if ethanol was used the product would be ethyl esters. The ester is then based catalyzed by either potassium hydroxide or sodium hydroxide. Both bases can be used to catalyze methyl ester, however, potassium hydroxide has been found to be more suitable for the ethyl esters process. The biodiesel and glycerin phases are gravity separated because the glycerin phase is much more dense and can be drawn off the bottom of the settling vessel the reaction took place in. Both phases then undergo a flash evaporation process or distillation (in some cases the alcohol is removed before the biodiesel and glycerin phases are separated). The alcohol that's removed is then used again in the base catalyzed transesterification process.
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The glycerin by-product contains unused catalyst and soaps which are neutralized using an acid so the by-product can be stored as a crude glycerin. Water and alcohol can be removed to produce a 80-88% pure glycerin which is then sold as crude glycerin. However, more sophisticated methods of removal can produce up to 99% pure glycerin, which can then be sold to cosmetic and pharmaceutical markets.

A small biodiesel mixing machine in Argentina.
A small biodiesel mixing machine in Argentina.

The final crude biodiesel can be purified by being gently washed with warm water to remove residual catalyst or soaps, dried, and then stored as an amber-yellow liquid with a viscosity similar to petroleum based diesel. Usually this is the final step in the distillation process but another step can be taken to distill the biodiesel and produce a colorless liquid. [3]

mportance of the Catalyst

A catalyst is a substance that increases the speed at which a reaction happens but remains unchanged throughout the reaction. Reactions only occur when the particles of combined reactants collide with each other with enough energy to start the reaction. The minimum energy required to start a reaction is known as the activation energy, and particles without this minimal amount will bounce apart instead of reacting together. [4] external image mbdistrib5.gif

To increase the rate of a reaction, the number of successful collisions between particles needs to be increased. Adding a catalyst to the reaction can do this because it provides an alternative route for the reaction that contains a lower activation energy for the particles.[5] In the case of sodium hydroxide in the base catalyzed transesterification reaction, the substance is a homogeneous base catalyst that catalyzes roughly 4000 times quicker than acid catalyzed transesterification.[6] It dissolves quickly in the alcohol used in transesterification, and increases the rate at which the triglyceride and alcohol exchange hydrogen atoms to form glycerin and either methyl ester or ethyl ester.[7] It's pH level of 14 makes it highly basic,[8] and as a result is highly reactive in transferring hydrogen ions between the two molecules.

History of Biodiesel
Rudolf Diesel
Rudolf Diesel

In the 1890s the diesel engine was invented by Rudolf Diesel. The engine ran on vegetable oil and many other types of fuel but the use of vegetable oil in the engine was ignored.
Beginning in the 1930s scientist began to alter vegetable oil in order to make it similar to petroleum. In order to make vegetable oil comparable to petroleum scientist split the fatty acids from the glycerin in vegetable oil. In 1937 G. Chavanne claimed a patent for the ethyl ester of palm oil. This is known as a biodiesel. During World War II vegetable oil was used for fuel, but shortly after it was forgotten. In the 1970s vegetable oil was used as fuel, as a result of the petroleum crisis; but it became problematic in engines since the vegetable oil was too thick. Scientists then figured out how to make the vegetable oil biodiesel, so it could be safely used in engines. The first biodiesel plant to make fuel was constructed in Austria in 1985. Biodiesel was first manufactured in Kansas City in 1991. Governments soon began to reward those that used biodiesel, since biodiesel is a healthy alternative to petroleum. Governments even required biodiesel to be used, this lead to an increase in the amount of biodiesel plants and production of biodiesel. The decrease in petroleum has lead to an increase in the demand of biodiesel. The only downside of biodiesel is the increase need of crops that are required for biodiesel.[9]
Biodiesel Plant
Biodiesel Plant

Applications in Real Life

external image 04387443735b93eac3d2e421f70a3c80.jpg The primary advantage of biodiesel is its reduced impact on the environment. Using biodiesel as an alternative to diesel will significantly reduce global warming. The production and use of biodiesel produces 78.5% less CO2 emissions than petroleum diesel. Biodiesel has been proven to be the best technology to be used in diesel applications. Biodiesel is also non-toxic, biodegradable, and free of sulfur and aromatics, which can cause harm to the environment.[10] Since there are an abundance of resources that biodiesel can be made from, it is more economically friendly when compared to petroleum. Petroleum has to be imported into our country. This is costly and harmful to the environment. Biodiesel can be made from simple substances such as vegetable oil, which means that products for biodiesel do not need to be imported. The process to make bio-diesel is so simple that you can even make biodiesel yourself . The simplicity of biodiesel makes it substantially cheaper than petroleum. Since biodiesel is composed of waste products, the use of biodiesel helps to use waste products that would be disposed of instead of being used.[11] In the world of biodiesel there are many different types of biodiesel for different applications. Biodiesel is characterized by the letter B and a number (for example B20). The number after the B explains the percent of biodiesel compared to the percent of petroleum in the fuel. For some that would want to be more green when buy fuel they would get a B80 fuel or above. The higher the number, the higher the performance of the biodiesel is.[12] external image 34083190_c53eea9020.jpg

Cool Stuff

Earthrace is a 100% biodiesel driven boat. Earthrace, holds the record for the time it takes for a motorized boat to travel completely around the globe. Earthrace completed the journey around the earth in just 60 days. The boat can travel 13,000 nautical miles on just one tank of biodiesel, that is more than half way around the earth. The boat can also travel 23 feet underwater. Aside from traveling around the world in 60 days, the boat is planned to be used as a transportation device to track illegal hunters and poachers in the ocean.[13]

external image bullet_485.jpg
The biodiesel bike was created by Micheal Stuart and his team. The 'bullet bike' is intended to reach extremely fast speeds even though it is street legal. The bike was hand made and has reached 130 miles per hour. The bike releases 78% less net CO2 compared to a regular diesel engine.[14]

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Recently Amtrak created a biodiesel train that runs completely off of a fuel that is made from beef byproducts. Biodiesel has been used as fuel for other trains but Amtrak's train runs on much more biodiesel than other trains. Trains that have been completely remodeled to run on biodiesel, can run on B20 biodiesel (20% biodiesel/80% petroleum). Amtrak's train is beneficial to the environment but scientists are pondering how enough fuel based off of entirely beef byproducts will be found.[15]

Works Cited

"Advantages Of Biodiesel." Make Biodiesel Fuel At Home | Save Money On Gas. 2008. Web. 02 June 2010. <>.

"Biodiesel 101."
National Biodiesel Board - - Web. 02 June 2010. <>.

Clark, Jim. "The Effect of Catalysts on Rates of Reaction."
Chemguide. 2002. Web. 05 June 2010. <>.

"Dow Caustic Soda."
DOW. The Dow Chemical Company. Web. 4 June 2010. <>.

Earthrace - Racing Around The World For A Better Planet
. Web. 04 June 2010. <>.
"History of Biodiesel." EXtension. 14 Apr. 2010. Web. 03 June 2010. <>.

Hsu, Jeremy. "Get on the Beef Train: Amtrak Unveils First Biodiesel Commuter Train, Powered By Animal By-Products."
Popular Science. Bonnier Corporation, 26 Apr. 2010. Web. 04 June 2010. <>.

Mone, Gregory. "The Biodiesel Bullet Bike | Popular Science."
Popular Science. Bonnier Corporation, 6 July 2007. Web. 04 June 2010. <>.

"Sample Application Letter for Biodiesel."
California Department of Food and Agriculture. 2010. Web. 2 June 2010. <>.

"Sodium Hydroxide."
Scorecard Home. Web. 05 June 2010. <>.

Viswanathan, B., and A.V. Ramaswamy.
Selection of Solid Heterogeneous Catalysts for Transesterification Reaction. Rep. Indian Institute of Technology. Web. 4 June 2010. <>.

"What Is Biodiesel."
ESRU Web Site. Web. 03 June 2010. <>.
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