As oil prices continue to rise and the resulting pollution from combustion continues to damage the natural environment, ethanol becomes a viable alternative. Ethanol is a renewable fuel, refined from a variety of organic sources. Ethanol potentially could replace oil, or provide a means to lessen the dependency on these fuels. This paper observes the issues associated with ethanol fuels and aims to answer all of the associated questions.
The sources from which ethanol is produced and some of the modern alternatives are discussed in this paper. These sources include sugar, corn and wheat, along with alternative sources such as biomass and sorghum. The process of refinement of the raw materials is observed through to the final product. First, wet milling and dry grinding to break the materials down to sugars is investigated. Then fermentation to produce alcohol and the dehydration processes to make the fuel acceptable for combustion are discussed along with possible alternatives to current practices. Finally the costs to the consumer of ethanol are considered. This involves both the costs on refinement and the financial incentives in place both here and in other economies where ethanol is consumed in significant quantities.
The interactions between ethanol and the internal combustion, is of the greatest importance for ethanol as a fuel. The physical properties of the fuel, as well as safety and handling issues are highlighted from the material safety data sheets (M.S.D.S.). The fuel properties like the internal energy and flame temperature are considered to help compare the fuel to unleaded petroleum or gasoline. Also the properties of the fuel as the concentration changes is analysed, be it 10% ethanol (E10), 20% (E20), 85% (E85) and 100% (E100). An overview is also provided of the ethanol usage of other countries, in conjunction with vehicle manufacturer recommendations, to help obtain a perspective of the possibilities for ethanol in Australia. The ethanol emissions are analysed and quantified in comparison to an unleaded petroleum engine, these emissions include CO (Carbon Monoxide), HC (Hydro Carbons), CO2 (Carbon Dioxide) and NOX (Nitrous Oxide). Also the performance of ethanol engines and the effect of varying the engine characteristics are discovered.
Another aspect of consideration is the wear on the internal combustion engine with ethanol fuels. In Australia, at the turn of the century the introduction of ethanol in a concentration up to 20% was a seriously considered option. To help the decision making process, the Orbital Engine Company was commissioned to investigate the issues and conduct the required tests to gain a perspective on the wear of the internal combustion engine along with its many associated components. To do this they observed motor vehicles, marine engines and utility motors. They performed operation tests and submersion tests to observe material compatibility. To validate these results, more focused tests were used which observed abrasive wear in ethanol environments and environments where ethanol is being burnt.
A decision has been made about the concentrations of ethanol in fuel, with E10 being the chosen concentration. However, ethanol is used in motor vehicles in concentrations much greater than E20 in countries such as the U.S.A. and Brazil, with E85 and E100 fuels respectively. They use these high ethanol content fuels due to the agricultural productivity of America’s Mid-West and the sugar cane plantations of Brazil. Australia is fortunate enough to grow in large quantities the raw materials for ethanol. Hence an investigation into what is required to introduce high ethanol fuels is required. The benefits of implementing high ethanol fuels is also shown through fleet tests conducted in both Idaho U.S.A. and China.
All of these things were done so that a perspective on all the issues involved with ethanol is given to the reader. Thus an accurate assessment can be made of the effects of ethanol on Australia’s motor vehicles, based on the performance, efficiency, emissions, wear and costs.