Biodiesel ahead in fuel race
By Rodney Magazinovic
The recent hike in petrol prices has reinforced just how precarious our fuel reserves are becoming. With future prices only likely to increase, governments worldwide are encouraging the development of alternative fuels that are both cheaper and more environmentally friendly..
Since joining UniSA in 2002, senior lecturer Dr Saiful Bari from the School of Advanced Manufacturing and Mechanical Engineering, has led a research team developing alternative fuels such as biodiesel.
The project is supported by the South Australian Department of Transport and is investigating the efficiency of using biodiesel blends as a replacement for petroleum diesel in vehicles. Two-thirds of Adelaide buses run on biodiesel. Dr Bari says modern diesel engines require a clean-burning, stable fuel that performs well under a variety of operating conditions.
“Biodiesel is the only alternative fuel that can be used directly in any existing, unmodified diesel engine. As it has similar properties to petroleum diesel, biodiesel can be blended in any ratio with petroleum diesel,” Dr Bari said.
Biodiesel can be created from raw vegetable oils such as canola, animal fats and waste cooking oil. The most common manufacturing technique is to react the raw oil with methanol in the presence of a catalyst. The resultant product is biodiesel and glycerine, with the latter being removed. This process has many advantages, including the fact that both the methanol and catalyst can be recovered and reused.
With most diesel engine manufacturers permitting the use of B20 (a 20 per cent biodiesel to 80 per cent petroleum diesel blend) only before engine warranties are voided, maximising the efficiency of existing diesel engines running on B20 biodiesel has been a priority.
“Biodiesel is the perfect fuel for engines. Previous studies have shown that the more biodiesel used in the blend, the greater the reduction in engine power. The key has been to make some modifications to current diesel engines so that its use is optimised. We have been able to show that when changes are made to the ignition timing in the engine there is no power loss with B20,” Dr Bari said.
While producing biodiesel from domestic crops has such economic benefits as reducing Australia’s dependence on foreign petroleum, increasing agricultural revenue, and creating jobs, Dr Bari says that there are also significant positives for the environment.
“With waste cooking oil not being easily disposed of, any process in which it can be re-used is obviously going to be beneficial to the environment,” he said.
“Canola is a renewable source. The plants are harvested and converted to biodiesel. Any carbon dioxide emissions from the burning of the fuel in the engine are then absorbed by the next generation canola crop – there is no net carbon dioxide contribution to the environment.”
Emissions from biodiesel are much less than petroleum diesel. Particulate matter is reduced by about 60 per cent with hydrocarbon and sulphur dioxide emissions also significantly lower. The only downside is that nitrous oxides emissions are higher. A future project to be supported by South Australian Farmers Fuel will investigate the effectiveness of a nitrous oxides inhibitor that is added to biodiesel.
While Dr Bari concedes that biodiesel is not the only solution to future fuel shortages, he believes it will be a combination of alternative fuels that will power our transportation needs.
“Biodiesel has the potential to fuel 10 to 15 per cent of the demand of powered vehicles on the road so there is still a need to develop other complementary alternative fuel sources for the remainder.”