Introduction
Ethanol is the common name for Ethyl Alcohol (ETOH). If you looked at ethanol at a molecular level, you would see that ethanol is made up of a group of chemical compounds with molecules that contain a hydroxyl group –OH bound to a carbon atom (C2H5OH) (Appendix 1, Figure 1). In diluted form, ethanol has a sweet taste, but in concentrated forms it has a burning taste.
A brief history of ethanol
Ethanol has been used by humans since prehistoric time as the intoxicating ingredient in alcoholic beverages. Dried residues on 9000-year-old pottery found in northern China show the use of alcoholic beverages even among Neolithic peoples. Ethanol’s isolation as a relatively pure compound was first achieved by Islamic alchemists who developed the art of distillation during the Abbasid caliphate (820 A.D.). Distillation of ethanol from water yields a product that is at most 96% ethanol, because ethanol forms an azeotrope with water. Absolute ethanol was first obtained in 1796 by Johann Tobias Lowitz, by filtering distilled ethanol through charcoal. Antoine described ethanol as a compound of carbon, hydrogen, and oxygen, and in 1808, Nicolas de Saussure determined ethanol's chemical formula. In 1858, Archibald Couper published a structural formula for ethanol: this places ethanol among the first chemical compounds to have their chemical structures determined. Ethanol was first prepared synthetically in 1826, through the efforts of Henry Hennel in Britain and S.G. Sérullas in France. Michael Faraday prepared ethanol by the acid-catalysed hydration of ethylene in 1828, in a process similar to that used for industrial ethanol synthesis today.
How is ethanol produced?
Ethanol is produced by fermenting and distilling starch crop that have been broken down into simple sugars. In Canada, the main items used to create ethanol are wheat and corn. Each bushel of corn processed yields 2-1/2 gallons of ethanol and several valuable by-products.
I have summarised different methods of producing ethanol in the following paragraphs:
1. The dry-grind process is the most common method used to make fuel grade ethanol. In this method, the whole corn kernel is ground and converted into ethanol. This method is relatively cost effective and requires less equipment than wet milling, but is not ideal for mass producing and gives off no side products.
2. Ethanol is also produced by the wet milling method. In the wet milling process, corn is separated into its four basic components: starch, germ, fiber, and protein, which are each made into different products. The advantage of wet milling is that, besides ethanol, valuable co-products such as corn oil are also produced (Appendix 1, Figure 2). The disadvantages are that the equipment is expensive and the process uses hazardous sulfur dioxide. During conventional wet milling, corn is steeped for 24 to 36 hours in water and sulfur dioxide to begin the separation of the starch and protein connections. Then the corn is coarsely ground to break the germ loose from other kernel components. Later, the starch is separated out and converted into sweeteners or ethanol.
Vijay Singh, a professor from the University of Illinois, and David B. Johnston has developed a more cost effective way of producing ethanol using wet-milling. The new method includes a 6-hour soaking in water of the corn kernels before milling. After about 3 hours of soaking, the enzymes are added. Then normal wet-milling steps are resumed. In laboratory and pilot-scale trials, the enzyme method separated starch and proteins faster and yielded starch equal to or greater than the conventional process. Currently, ethanol yields 25% more energy output than input to produce it. Scientists around the world are researching less costly ways of producing ethanol, and better ways to blend it with gasoline so that we will not have to destroy Earth’s ecosystem in order to run our vehicles and other machines.
3. Recently, Scientists at the Virginia state Polytechnic Institute have developed a breakthrough method of ethanol production method called Advanced Bioethanol Technology (ABT) which lets producers create ethanol from any biological feedstock that contain enough sugars or materials that can be converted into sugar such as starch or cellulose. ABT breaks long chains of sugars down to be fermented.
History of ethanol as a fuel
Ethanol has been used as a fuel in the United States since at least 1908 with the invention of the Ford Model T which could be modified to run on either gasoline or pure alcohol. Henry Ford designed the famed Model T Ford to run on alcohol saying that it was "the fuel of the future". Ethanol was used well into the 1920's and 1930's to fuel cars alongside an effort to sustain an US ethanol program. Although these early efforts failed, oil supply disruptions in the Middle East and environmental concerns over the use of lead as a gasoline octane booster renewed interest in ethanol in the late 1970s in the western countries.
Now, ethanol has become a formidable force in today’s fuel industry and is viewed as an environmentally friendly renewable fuel. The main reason ethanol is creating an interest as an alternative fuel is due to growing concerns about global warming, climate change and the depletion of non-renewable resources that are used to produce currently used fuels. Ethanol releases less pollution and it is derived from renewable sources such as corn and other starch products, compared to our conventional fuels, diesel and gasoline, which are derived from fossils.
Ethanol: an alternative fuel
The most common blend of fuel ethanol is E10 which is 10% ethanol and 90% gasoline, because most internal combustion engines today are not designed to sustain high levels of ethanol. There needs to be a little bit gasoline in the blend in order for the engine to start on cold days, and to stop the fuel tank and engine from rusting. E10 is not considered an alternative fuel under the Energy Policy Act of 1992 (EPAct). E10 and lower can be used in most vehicles that run on gasoline. Higher blends like E85 and E95 which are considered alternative fuels under the EPAct require special vehicles called FFV’s (Flexible Fuel Vehicles). FFV’s have special engines that can take on high amounts of alcohol which is normally corrosive to metal. Today, ethanol is considered the fuel of the future with 400 pumps in the United States, selling different blends of ethanol and FFV’s already on the road.
In the search of environmentally friendly and sustainable alternatives to fossil based fuel industry, many countries around the world have started ethanol production at commercial level. Currently, Brazil produces 15 billion litres of ethanol per annum with the USA in second place producing close to 14 billion litres per annum. Sadly, Canada is at the 14th place with only 245 million litres production per annum (Appendix 1, Table 1). As of mid-2002, five plants producing fuel ethanol were operating in Canada: one each in Alberta, Saskatchewan and Manitoba and two in Ontario, with a total production capacity of about 175 million litres of fuel ethanol per year. Several other plants were in the planning stage, with the potential to significantly increase Canada's annual production
So, why did I want to do this project?
Even though ethanol is a very promising alternative to conventional fuels, it faces the problems of mass productions and large scale commercialization, due to lack of knowledge about ethanol and its properties pertaining to its fuel efficiency, and burn ratio compared to today’s trusted fuels. Burn ratio/duration is determined by two factors, the amount of oxygen in the fuel, and the octane level of the fuel. The octane level is determined by the number of carbon atoms in the molecule of the fuel. An interesting question is, “What is the trade off between sustainability, environmentally cleanliness and fuel efficiency?” More research is needed to examine the comparative effectiveness of ethanol as a fuel, compared to those available in market today.
My question was: “How does ethanol as a fuel compare to diesel and gasoline, today’s conventional fuels?”
To answer my question, I designed and performed three experiments to compare ethanol with today’s common fuels, diesel and gasoline, for fuel grade (or burn duration), energy content in terms of Btu, and pollution emissions. I hypothesized that diesel would have the highest burn duration, gasoline second, and ethanol the least, because of their respective octane ratings. For comparing energy content of ethanol with diesel and gasoline, I hypothesized that ethanol would have the highest energy content, and gasoline, and diesel would have comparable energy content levels. I based this hypothesis on findings of a study about race cars comparing ethanol to high octane gasoline. For my third experiment dealing with emissions, I hypothesized that ethanol would give off the least pollution, followed by gasoline and diesel. This was based on my first hand experiences from my first two experiments.