Biodiesel - Page 10

Biodiesel

Biodiesel is defined as a fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats. A “mono-alkyl ester” is the product of the reaction of a straight chain alcohol, such as methanol or ethanol, with a fat or oil (triglyceride) to form glycerol (glycerin) and the esters of long chain fatty acids.

Biodiesel is an alternative fuel formulated exclusively for diesel engines. A major application of the BioCRUDE Technology is to synthesize biodiesel from organic waste and manure. The focus for the R & D Department has been to optimize the process of obtaining the oil, designing an adequate transesterification procedure, and to evaluate the advantages and cost-benefits of production. It is important to stress that the BioCRUDE technology is a NEW alternative to obtaining biodiesel from vegetable oils, manure and animal fats. Although the individual processes have been used and tested in other research projects and universities, it is the MIX of processes that is innovative and unique to this product.

Biodiesel can be mixed with petroleum diesel in any percentage, from 1 to 99, which is represented by a number following a B. For example, B5 is 5 percent biodiesel with 95 percent petroleum, B20 is 20 percent biodiesel with 80 percent petroleum, or B100 is 100 percent biodiesel, no petroleum.

 

Biodiesel By-products

Biodiesel is normally produced from either virgin plant oils or waste vegetable oils through a catalytic transesterification process. The typical biodiesel production process uses an alkaline hydrolysis reaction to convert vegetable oil into biodiesel using methanol, potassium hydroxide, and heat. A transesterification reaction splits the glycerol group from the triglyceride oils, producing methyl esters (biodiesel) and glycerol by-product. To purify the biodiesel, a washing process is employed to remove soaps, free fatty acids, and excess methanol, producing a wash water by-product. For every 100 L of oil, approximately 25 L of methanol and 0.8 kg of KOH/NaOH is consumed, yielding around 75 L of biodiesel and 25 L of crude glycerol. The washing process produces another 30 L of biodiesel wash water. Both the crude glycerol and the biodiesel wash water have significant methane production potential. When vegetable oil is pressed from seeds (or algae), there is also a press-cake by-product along with crop residues from harvesting that are both amenable to biogas production. Conversion of biodiesel by-products to methane offers a sustainable treatment solution, while also providing additional energy. Methane can also be converted to methanol, an ingredient used in biodiesel production. Also, digester effluent could be used to grow algae for biodiesel production.

 

Advantages

Biodiesel is closer to being cost competitive with petroleum diesel, but the available supply of recycled oil from other applications will probably limit its use for biodiesel production. Unless alternatives such as the oil extraction from manure and waste make feasible oil prices decline dramatically. The largest market for biodiesel probably will be as a fuel additive. The ultra-low-sulfur diesel program will offer an opportunity for biodiesel as a lubricity additive and perhaps as a cetane booster as well. Biodiesel may also be marketed for applications in which reducing emissions of particulates and unburned hydrocarbons are paramount, such as school and transit buses.

1. Biodiesels are biodegradable.

2. They are non-toxic.

3. They have significantly fewer noxious emissions than petroleum-based diesel when burned.

4. They are renewable.

5. With a much higher flash point than it is for petrodiesel (biodiesels have a flash point of about 160 °C), biodiesel is classified as a non-flammable liquid by the Occupational Safety and Health Administration. This property makes a vehicle fueled by pure biodiesel far safer in an accident than one powered by petroleum diesel or the explosively combustible gasoline.

6. Biodiesel is the only alternative fuel that runs in any conventional, unmodified diesel engine.

7. Biodiesel can be used alone or mixed in any ratio with petroleum diesel fuel. The most common blend, however, is a mix of 20% biodiesel with 80% petroleum diesel, or "B20."

8. Biodiesel is about 10% oxygen by weight and contains no sulfur. The lifecycle production and use of biodiesel produce approximately 80% less carbon dioxide emissions, and almost 100% less sulfur dioxide.

9. Combustion of biodiesel alone provides over 90% reduction in total unburned hydrocarbons and a 75-90% reduction in aromatic hydrocarbons. When burned in a diesel engine, biodiesel replaces the exhaust odor of petroleum diesel with the pleasant smell of popcorn or french fries. Biodiesel further provides significant reductions in particulates and carbon monoxide than petroleum diesel fuel. Thus, biodiesel provides a 90% reduction in cancer risks.