Bio-diesel is a generic name for methyl or ethyl esters made from any tri-glyceride oil molecule. Tri-glyceride oils include all plant oils such as Canola, Mustard, Sunflower, Safflower, Soy, Corn oil, etc. Used cooking oils can also be used as well as fats and tallows. A chemical process called “transesterification” is used to “crack” the glycerol molecule and replace it with an alcohol molecule. A catalyst is used such as Sodium hydroxide (Caustic Soda) or Potassium hydroxide and an alcohol such as methanol or ethanol.
The benefits of Biodiesel
Fuel made from vegetable oil has a number of distinct advantages over fossil fuel. Firstly, it is renewable and has positive environmental benefits. Instead of releasing stored carbon into the atmosphere, we are basically cycling carbon. Sunlight and CO2 are two important inputs that a plant needs to grow, and essentially the amount of carbon that is stored by the plant during its growing cycle is the same as what is released during combustion. This fact gives us a distinct production advantage in that photosynthesis occurs naturally, in which the majority of the energy requirements are provided free by the environment. This results in a net energy benefit or a positive energy balance ratio.
An energy balance ratio is a comparison of the energy stored in a fuel to the energy required to grow, process and distribute that fuel. The energy balance ratio of bio-diesel is at least 2.5 to 1. For every one unit of energy put into the fertiliser, pesticides, fuel, feedstock, extraction, refining, processing and transporting of bio-diesel, there are at least 2.5 units of energy contained in the bio-diesel. Bio-diesel has a positive energy balance ratio because it is an efficient carrier of solar energy.
Extensive tests have demonstrated that the use of a B20 blend (20%bio-diesel, 80% diesel) can reduce unburned hydrocarbons by 14%, decrease carbon monoxide by 9%, reduce particulate matter by 8%, decrease sulphates by 20%,and decrease PAH (Polycyclic Aromatic Hydrocarbons) emissions by between 13% to 50% .
At a 20% blend, there is an increase of Nitrous Oxide by 1% (a noxious greenhouse gas).
Research in a paper entitled, “Fueling diesel engines with blends of methyl ester soybean oil and diesel fuel”, concluded that “Fueling with bio-diesel/diesel fuel blends effectively reduced particulate matter, unburned hydrocarbons and carbon monoxide while increasing oxides of nitrogen emissions. The optimum blend of bio-diesel and diesel fuel, based on the trade-off of PM decrease and NOx increase was a 20/80 bio-diesel/diesel fuel blend.
Increased NOx emissions can be reduced by retarding engine timing while subsequently maintaining emission reductions associated with fueling a diesel engine with a 20/80 bio-diesel/diesel fuel blend. The retarded timing lengthened the ignition delay time. This reduced the peak pressure and temperature that enhanced the formation of NOx emissions.” With the introduction of low sulphur fuel the possibility exists to also use a catalytic converter in conjunction with retarded timing to reduce NOx emissions.
Safe for us and the environment
Bio-diesel also degrades rapidly in the environment and is non-toxic. The LD 50 test (lethal dose) is greater than 17.4 g/kg body weight. In comparison, table salt is nearly 10 times more toxic.
Bio-diesel degrades at the same rate as sugar. Within 28 days, pure bio-diesel degrades 85 to 88 percent in water. Blending bio-diesel with diesel also accelerates its biodegradability. A blend of 20% bio-diesel and 80 % diesel degrades twice as fast as diesel alone. It is the low toxicity, degradability and safety of bio-diesel that make it a safe fuel to use in environmentally sensitive areas. There have been reports of companies actually using bio-diesel to breakdown and degrade oil spills.
Bio-diesel is also extremely safe to store. It has a flash point of over 300 degrees Fahrenheit whereas petro diesel has a flash point of around 125 degrees Fahrenheit.
Storage and handling requirements are virtually the same as for diesel storage, except that copper, brass, lead, tin and zinc storage containers should be avoided
The best part of all this, is that bio-diesel can be used in any diesel engine at any ratio, with little or no engine modification necessary. However, as with all good things, bio-diesel has a downside. Bio-diesel has solvent like properties which may release accumulated deposits on fuel tank walls and fuel pipes. Bio-diesel at high concentrations over a period of time may also soften natural and synthetic rubber seals and hoses, and it is advisable to eventually replace these components with “viton” or similar parts.
Initially there may be some inconvience as fuel filters become clogged. Once the deposits have been removed, there will be no further problems.
The road ahead?
Importantly, there is no need to move away from the existing internal combustion engine technology and infrastructure. Billions of dollars of investment has been spent in the current engine technology and the use of bio-diesel will allow the world the continued use of this infrastructure.
The necessary infrastructure to distribute bio-diesel is already in place and simply uses the existing fossil fuel network. Joshua Tickell, in a recent presentation explained, “there is approximately 15 trillions dollars invested in the current fossil fuel infrastructure. To change to a totally new infrastructure would bankrupt every country in the world.”
The skills and technology to produce oilseed crops also exist. Since the introduction of rapeseed, we have seen the phenomenal growth in the oilseed industry with numerous Canola varieties being released…almost one to suit every application of broardacre farming. The dawn of the Genetic enhancement era may also lead to major advancements in breeding, benefits that may not be achievable with conventional techniques.
With a vegetable oil based energy economy, all of a sudden, the whole energy market is de-centralised. Every nation either has the capacity to grow vegetable oil, fats and tallows or access them. The few multi-nationals who have control over exploration, extraction, refining and distribution of the worlds energy loose their power. All of a sudden, it is possible even for the worlds poorest countries to be able to grow and produce their own energy demands and reduce their ever growing national debt. Wealth has a more equitable distribution, and with that comes new opportunities.
> back to top