What is Bio Diesel?

Bio diesel (fatty acid alkyl esters) is a cleaner burning diesel replacement fuel made from natural, renewable sources such as new and used vegetable oils, animal fats, and in particular from the seeds of the Jatropha Curcas tree. Just like petroleum diesel, bio diesel operates in compression-ignition engines. Blends of up to 20% bio diesel (mixed with petroleum diesel fuels) can be used in nearly all diesel equipment and are compatible with most storage and distribution equipment. These low-level blends (20% and less) generally do not require any engine modifications. Bio diesel can provide the same payload capacity and as diesel.

Higher blends, even pure bio diesel (100% bio diesel, or B100), may be able to be used in some engines

Using bio diesel in a conventional diesel engine substantially reduces emissions of unburned hydrocarbons, carbon monoxide, sulphates, polycyclic aromatic hydrocarbons, nitrated polycyclic aromatic hydrocarbons, and particulate matter. These reductions increase as the amount of bio diesel blended into diesel fuel increases. The best emission reductions are seen with B100.

The use of bio diesel decreases the solid carbon fraction of particulate matter (since the oxygen in bio diesel enables more complete combustion to CO₂) and reduces the sulphate fraction (bio diesel contains less than 15 ppm sulphur), while the soluble, or hydrocarbon, fraction stays the same or increases. Therefore, bio diesel works well with emission control technologies such as diesel oxidation catalysts (which reduce the soluble fraction of diesel particulate but not the solid carbon fraction).

Emissions of nitrogen oxides increase with the concentration of bio diesel in the fuel and the increase is roughly 2% for B20. Some bio diesel produces more nitrogen oxides than others, and some additives have shown promise in reducing the increases. More R&D is needed to resolve this issue.

Bio diesel has physical properties very similar to conventional diesel

How is Bio Diesel Made?

Bio diesel fuel can be made from new or used vegetable oils and animal fats, which are non-toxic, biodegradable, renewable resources. Fats and oils are chemically reacted with an alcohol (methanol is the usual choice) to produce chemical compounds known as fatty acid methyl esters. Bio diesel is the name given to these esters when they're intended for use as fuel. Glycerol (used in pharmaceuticals and cosmetics, among other markets) is produced as a co product.

Bio diesel can be produced by a variety of esterification technologies. The oils and fats are filtered and pre-processed to remove water and contaminants. If free fatty acids are present, they can be removed or transformed into bio diesel using special pre-treatment technologies. The pre-treated oils and fats are then mixed with an alcohol (usually methanol) and a catalyst (usually sodium hydroxide). The oil molecules (triglycerides) are broken apart and reformed into methyl esters and glycerol, which are then separated from each other and purified.

Approximately 55% of the bio diesel industry can use any fat or oil feedstock, including recycled cooking grease. The other half of the industry is limited to vegetable oils, the least expensive of which is soy oil. The soy industry has been the driving force behind bio diesel commercialization because of excess production capacity, product surpluses, and declining prices. Similar issues apply to the recycled grease and animal fats industry, even though these feedstocks are less expensive than soy oils.

Bio Diesel Benefits

One of the biggest factors of rising costs is the cost of electricity from oil. The advantage of having one’s own supply of bio fuel is to give a major reduction in the cost of fuel to create electricity, helping to save valuable foreign exchange.

It appears that the strongest motive for most of the bio diesel producers is that it is a renewable form of energy, especially when it has become obvious that fossil fuels are finite and supply security of mineral oils is an increasing risk, especially where a country has no control over the costs and importation of crude oil in an ever changing world.

Because little fossil energy is required to move bio diesel, it is a substitute or extender for traditional petroleum diesel, and special pumps or high-pressure equipment for fuelling are not needed. In addition, it can be used in conventional diesel engines, so special vehicles or engines to run bio diesel do not need to be purchased.

Scientists believe carbon dioxide is one of the main greenhouse gases contributing to global warming. Neat bio diesel (100% bio diesel) reduces carbon dioxide emissions by more than 75% over petroleum diesel. Using a blend of 20% bio diesel reduces carbon dioxide emissions by 15%.

Bio diesel also produces fewer particulate matter, carbon monoxide, and sulphur dioxide emissions (all air pollutants under the Clean Air Act). Since bio diesel can be used in conventional diesel engines, the renewable fuel can directly replace petroleum products; reducing the country's dependence on imported oil.

Bio diesel offers safety benefits over petroleum diesel because it is much less combustible, with a flash point greater than 150°C, compared to 77°C for petroleum diesel. It is safe to handle, store, and transport.

Increased production of agricultural crops for non-food purposes has offered the opportunity to utilise land, which otherwise would be set-aside as an unexploited resource. It is not a surprise that this argument is seen as a strong motive in favour of bio diesel