With increasing uncertainty in the global fuel market, the search for gasoline substitutes is becoming more and more important. One viable option is using ethanol as an alternative fuel, unlike fossil fuels, it is a renewable energy source. There are many chemical compounds that make up ethanol; the molecules contain a hydroxyl group, and are bonded to a Carbon atom. Ethanol that is made from cellulosic biomass instead of the usual starch crops is known as Bioethanol. Ethanol is in a liquid state, and is clear and colorless. As a diluted aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions, it has a burning taste.
The shift toward ethanol-based fuel has positive social, economic, and environmental effects. The combination of better efficiency with cleaner emissions yields makes it a promising future source of fuel. For transportation, ethanol can be blended with petroleum-based gasoline or can be used on its own. It has a chemical component that consists of ethyl alcohol, grain alcohol, and EtOH; it is also ethane with a hydrogen molecule replaced by a hydroxyl radical. When ethanol alone is used as fuel, it is mixed with a small amount of water, usually 5 percent of the total mixture.
SOURCES AND PRODUCTION PROCESSES
Ethanol is derived from several sources. Food products such as corn, wheat, sugar cane, and rice are all viable candidates for ethanol production. Ethanol is produced through the fermentation of the sugars supplied from these foods. Materials used in ethanol production are wood chips, yard waste, crop residues, and solid animal waste. It can be made from just about any feedstock that has ample amounts of sugar, or materials that can be converted to sugar, such as sugar beets, sugar cane, or organic materials containing high levels of sugar such as starch and cellulose. Corn is widely used to produce ethanol. There are certain elements that are not as easily converted to sugar, such as trees and grasses, which are made of cellulose. Ethanol is also made from a wet-milling process. Many larger ethanol producers use this process, which also yields products such as high-fructose corn sweetener. These other materials are viewed as potential sources of low-cost ethanol production, because corn may not always be practical for ethanol because land needed to grow corn is needed for food and feed corn.
There are several ways to produce ethanol. One method is to convert lignocellulosic materials to ethanol. This method involves two processes. The first step is the hydrolysis of cellulose in the lig-nocellulosic materials to fermentable reducing sugars. After hydrolysis comes the fermentation of the sugars to ethanol. Another mode of production involves cereal grains. The grains are milled, which produces amylase and heat. The results go through a gelatinization process, resulting in amyloglucosi-dase and yeast. Next, saccharification and fermentation are conducted, and the product is heated, and then distilled. This produces ethanol, as well as stillage. When heat is added to the stillage, dry grain is produced.
Ethanol can be manufactured from a variety of different naturally-growing carbon-based organisms. For instance, in India, sugar cane molasses, a byproduct of the sugar industry, contains 45-50 percent fermentable sugars, allowing India to efficiently produce a significant amount of ethanol. Fermentation represents an ideal way to produce ethanol, as it is easy to ferment these sugars, and quite cost effective.
USES And EFFECTS
Ethanol is used mainly as a fuel additive, replacing methyl tertiary butyl ether (MTBE). Thailand’s government has passed regulations to reduce MTBE emissions, and they are looking to ethanol for the answer. A 10 percent ethanol fuel mixed with gas, coined gas-ohol, is currently used, decreasing the amount of toxic volatile organic compound emissions. Diesel engines can use a 15 percent mixture of ethanol and gasoline, resulting in a visible reduction in fumes.
It is not feasible to completely replace gasoline with ethanol. It costs more for the United States to produce ethanol than gasoline. Turning to ethanol as a substitute, and possibly a primary fuel, has the potential to positively affect the environment, however. Ethanol burns cleaner than gas, releasing fewer volatile organic compounds into the atmosphere. Ethanol also runs up to one-third more efficiently than gasoline, while polluting less. Pure eth-anol fuel (95 percent ethanol, 5 percent water) has numerous benefits because of low pressure and the reduced emission of ethanol into the atmosphere, along with clean burning characteristics. Although there is some environmental benefit from using ethanol, there are also some environmental concerns, because ethanol is listed as a carcinogen for humans. The use of ethanol can lead the raising of peroxyacl nitrates (PAN), which is extremely toxic for plants. Ethanol combustion emits formaldehyde, also dangerous to humans. Health issues related to this include eye irritation, respiratory complaints, and nervous disorders.
The large-scale production of ethanol would have other effects. Because cars will need specialized parts, workers will be required to make and install them, Ethanol could create jobs in rural areas. There could also be a large swing from oil to agriculture if ethanol becomes a highly-sought resource. Different forms of agriculture may be developed to handle the demand for corn to produce ethanol. One such form is called biotech; however, its corn has not been proven healthy. There are limits to its production, also, as only a few companies comprise the entire ethanol business, and only one company in California holds the patent.
Another agricultural issue deals with the land requirements for corn production. One study estimated that almost one-fourth of the United States would need to be used to produce enough ethanol to replace gasoline. This raises issues of converting land from other uses to that of corn production. While the change from gasoline to ethanol is partially environmentally stimulated, the destruction of other environmental sites such as forests seems counter-productive.
Besides Thailand, many countries around the world are using ethanol in combination with gasoline. In the United States, Michigan produces and consumes the most ethanol. Many states are adopting a requirement that ethanol to be used as a fuel additive in place of MTBE. Brazil is a large producer and consumer of ethanol. Ethanol use in the United States is 10 percent, and 22 percent in Brazil.
Brazil and the United States intend to create an ethanol market to meet the needs of citizens. Last year, the United States produced 5.3 billion gallons of ethanol and imported another 720 million gallons, almost two-thirds of it from Brazil. Both the United States and Brazil have begun spreading agriculture and ethanol refinement technology to parts of the Caribbean and Central America to enhance sugar cane production, which, in turn, will enhance the production of ethanol. There are also many other sources of ethanol throughout the world; the top five areas are the United States, Brazil, China, France, and India. The United States not only imports from Brazil, but also from Jamaica, El Salvador, China, and Costa Rica. By 2010, it is estimated that Brazil will provide key ethanol resources with at least 77 more ethanol plants; this will help boost the production of ethanol by one-third, for a total of 7 billion gallons a year.
BENEFITS AND DRAWBACKS
Despite its advantages over MTBE, ethanol does have limitations. It has a lower BTU than gasoline, making it less powerful. It costs more to produce a gallon of ethanol fuel than it does to produce a gallon of gasoline. Ethanol is also corrosive to some metals, gaskets, and seals, and ethanol air mixtures can be explosive in the ambient temperature range. Land space is also a limiting factor, as large amounts of land are required for corn production.
Also, the substitution of ethanol has been noted to cause negative impacts on climate change. Despite the fact that it does not emit carbon dioxide into the atmosphere, it does release other toxins, and it does not reduce air pollution. Brazil’s air quality worsened during the big ethanol push in the 1970s. Compared to gasoline, ethanol produces less benzene and butadiene when burned, but more acetaldehyde and formaldehyde.
Driving the strong political backing for ethanol are energy security concerns, agricultural interests, and environmentalists. In the future, a drive for better efficiency could force ethanol to compete with electric cars and fuel cells, as well as gasoline. The trend for fuel seems to be shifting toward ethanol. In India, the blend of ethanol in gas is expected to double in the next few years. Brazil, because of their efficient sugar cane production, already produces ethanol for about 40 percent less than gasoline. More testing is needed on the health and environmental issues surrounding ethanol. As testing increases, cheaper ways of producing etha-nol will be implemented. Engines will likely become more efficient, and more cars are likely to come with ethanol-ready parts.
Ethanol also enhances the performance and maintenance of many old and new cars. Since etha-nol burns at cooler temperatures than gasoline, it does not burn valves. It may loosen noxious wastes and residues, usually in older cars, which have been deposited by previous gasoline fuels. However, changing the fuel filter will correct the problem and increase the performance of the car. Ethanol is used in aircraft as well, because it offers a low volatility, high-octane fuel to replace gasoline. Unlike many other fuel types, such as regular unleaded, unleaded plus, diesel, and premium, it can be used in any type of engine. Ethanol decreases the amount of water accumulated in an engine while providing better engine longevity. However, many people question whether ethanol provides good performance if used without gas line antifreeze.
Ethanol appears to be viable as an alternative fuel. Once solutions are found to its pollutant problems, ethanol may become even more desirable. It appears to be better for the environment than gasoline. It may create jobs, and free the United States from dependence on foreign oil. An electric hybrid using etha-nol fuel may be the future of the automobile industry. Ethanol as an alternative fuel is a good, currently available solution to the problem of diminishing fossil fuel supplies.
