Biodiesel are biofuels used in operation of engines. They contain vegetable oil and animal fats (biomass). Biomass is composed of organic compounds such as esters, methyl and ethyl groups. Biodiesel is a renewable source of energy. The basis of production of biodiesel is by chemical reaction between an alcohol and fats to produce fatty acid esters.
Alcohol are organic homologous series, having functional group of (-ROH). Alcohol can be primary, secondary and tertiary. Ethanol as an example of alcohol is basic constituent of biodiesel. It can be extracted from grains such as rice, potatoes skin, tree bark, sugar cane and many more. It can also be extracted from cassava.
Biodiesel are meant to operate on engine without knocking. Pure biodiesel can be use without blending. They are non toxic, biodegradable and less harm to life. Also, biodiesel can be blended with petroleum product (petrol diesel) in different proportions. Many measurement systems use “B” as a conventional symbol for biodiesel mix. The common examples are B20, B100.
|Specification||B composition %|
|B5||5 biodiesel & 95 petro disel|
|B20||20 biodiesel & 80 petro diesel|
|B99||99 biodiesel & 1 petro diesel|
ASTM has developed various specifications for production and conventional diesel (ASTM D995). Low level biodiesel (B5 &B20) are considerably safe in engine operations. That means, biodiesel can operates on both light and heavy duty truck.
B5 & B20
These are the most prevalent blend used in USA. B20 is produced in the specification under ASTM D7467-17. The low level blend requires no modification. ASTM has approved new specification between 6%-20% biodiesel. Many corporations accepted this blend but it is necessary that any producer should enquire of energy policy Acts of 1992 and ASTM regulations.
B99 and B100 is the common blend in this category. They are commercially available; but B100 is less sold in USA. B100 can operate in engines as hoses and gaskets. These engines have biodiesel compatibility parts. For production, B100 should meet the ASTM D6751-5cel specification. The operating engine of B100 requires modification.
Biodiesel has solvent properties in vehicles. It also has water contaminants. This is because of the presence of mono and diglycerides. Water can cause corrosion of fuel parts of an engine. It is advised that fuel filters should be changed once an engine starts using biodiesel blends. They have lubricating properties and cetane rating. Cetane is an aliphatic hydrocarbon C16H34 used as a standard diesel fuel. Biodiesel should have good performance limit compatibility. It should have good emission properties.
Other uses of biodiesel
Oil spillage cleanser:
In river line areas where oil spillage is common; biodiesel can be used to cleanse such damages. This is possible because of the presence of methyl esters constituent and this reduces the viscosity of crude oil.
Biodiesel can serve as a heating fuel for domestic and industrial applications. The combination of heating oil and biofuel is called bio-heat. This is a recognized fuel under National Biodiesel Board (NBB) and NORA. Bioheat can be found in various blends eg 5% and 20% biodiesel.
Some designs fuel engines are not based on biodiesel accommodation. Notice that heavy duty engine can operate on biodiesel blends. Biodiesel should combust efficiently with low emission properties. EPA tells us more about the emission regulation. In an injection engine, atomization control has a greater yield to emission of diesel engines.
The energy emitted by a fuel (biodiesel) depends on the blend, quality and system condition. The thermal efficiency of different blend differs because of difference in flash point, specific gravity and viscosity (physical properties). The physical properties can be studied under the American Society of Testing and Material for quality purpose. ASTM table for biodiesel blends