1109497255 2004 chemistry assessment task sarah colenbrander

8/3/2019 1109497255 2004 Chemistry Assessment Task Sarah Colenbrander

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PART ONE:

(a) Summarise the use of ethanol as an alternative car fuel and assess its

potential to be used as this.

(b) Evaluate the success of current usage of ethanol as a fuel and discuss its

advantages and disadvantages.

Ethanol production is escalating throughout the world, as it becomes increasingly

useful as a fuel, alcohol and/or solvent. Many nations are encouraging the use of pure

ethanol or ethanol blend fuels. The 1970s Pro-Alcohol program in Brazil, for instance,attempted to reduce the country’s dependence on oil imports and thus its vulnerability to

soaring prices. Today, ten percent of total national energy output in Brazil is from ethanol

combustion, while nearly half the cars operate on pure ethanol.

Current use of ethanol as an alternative car fuel:

Henry Ford’s Model T Ford, built in the 1880s, was the first car designed to run

on pure ethanol. However, gasoline fuels became more common because petroleum- powered engines were simpler to construct and operate, and because the discovery of

various extensive oil fields ensured a growing supply of cheap petroleum.Today, the use of ethanol or ethanol-blend fuels is on the increase. This is due to

rising awareness of ethanol’s environmental advantages and greater cost efficiency.

E10 (a blend of 10% ethanol and 90% petroleum) is far more common than pure

ethanol or E85 fuels in Australia. It is reasonably successful because it increases thefuel’s octane rating and acts as an oxygenate, encouraging complete combustion and

hence liberating more heat. Furthermore, adding ethanol to petrol reduces costs for fuel

suppliers. To date, there is no legislation concerning the ethanol:petrol ratio or requiringconsumers to be informed of the proportion of ethanol in a fuel. However, recent media

publicity has called for the Federal Government to set a limit of ten percent ethanol for fuel blends or to ensure that ethanol blends are labeled appropriately.Currently, pure ethanol or E85 (an 85% ethanol, 15% petrol combination) is

rarely used as an alternative car fuel in Australia. Extensive, expensive modifications are

required to run a normal engine on pure ethanol and few engines designed to run onethanol are sold. In many other nations around the world, such as Brazil and the USA,

“Flexible Fuel Vehicles” are becoming increasingly popular. These vehicles run on E85

and are produced by Ford, General Motors, Daimler-Chrysler, and Mazda. 5.5 million

FFVs will be on the roads in the USA during 2004.Another ethanol alternative is the ‘injection method’, which is becoming

gradually more widespread in diesel engines. In this process, gaseous ethanol is injected

into the turbocharger’s air stream. By replacing about twenty-five percent of diesel fuel,ethanol allows similar mileage, increased engine power and diminished toxic and

greenhouse emissions.

Potential use of ethanol as a car fuel:

Ethanol has considerable potential as an alternative car fuel. In environmental

terms, ethanol is a dramatic improvement on petroleum. Furthermore, it has long-term



economic benefits for the consumer and Australia as a whole. These advantages are

described in more depth under the next subheading.

However, it would be a complicated and expensive process to change to ethanol- powered cars. As yet, petrol is still a cheaper and more efficient fuel than ethanol (in

km/L), so consumers would oppose such a change. From an industrial perspective, petrol

is easier to distribute because of a clearly established infrastructure. An immediate supplyis also guaranteed, while Australia’s ethanol industry would need to be considerably

expanded to supply the nation with car fuel.

Therefore, although ethanol has a great deal of potential as a car fuel in the long-term, it is not yet an economically viable alternative. The transition stage from petrol to

ethanol would be both difficult and costly for consumers, suppliers and the Australian

government. Ethanol has little potential as a fuel for the immediate future, but with

further research, it is possible that ethanol will become the fuel of the future.

Advantages of using ethanol:

Ethanol has several advantages as a fuel. However, before these can be described,the structure and combustion reactions of ethanol need to be known, and an explanation

of the production process must be offered.

Chemical formula of ethanol Structure of ethanol

Complete combustion

Ethanol can be produced through the hydration of ethane or by the fermentation

of glucose (from cellulose, starch or sugar, usually from wheat or sugar cane). The production of ethanol through fermentation is illustrated in the flow chart:

Distillation anddehydration

Storage anddistribution

Ethanol fuel to be used in cars

FermentationY east & Enzymes

Acid and Lime

Treatment (Cellulose

-based ethanol only)

Grinding andmashing

Starch- or cellulose-

based feedstock

respectively



1. Ethanol is an environmentally friendly fuel.

• Ethanol is ‘greenhouse neutral’, i.e. when harvested with solar-powered

machinery, the carbon dioxide produced during combustion is equal to thatrequired for production/growth. Since carbon dioxide is partially responsible for

the greenhouse effect, ethanol is an environmentally friendly alternative. By

contrast, when fossil fuels are burnt, carbon (which has been stored undergroundfor millions of years) combusts to release carbon dioxide. Increased carbon

dioxide in the atmosphere is widely accredited for the global warming

phenomenon. Even ethanol-blend fuels such as E10 or E85 reduce greenhouseemissions. Hence, ethanol is a better alternative than fossil fuels.

• Ethanol does not pollute groundwater, so it is an ideal additive to increase theoctane rating. Alternative oxygenates, such as methyl tertiary butyl ether (MTBE),

are severe groundwater pollutants.

• Most hydrocarbon fuels often undergo incomplete combustion in the absence of

oxygen. Since ethanol has an oxygen atom in each molecule, it almost alwaysundergoes complete combustion. Thus, the output of the poisonous pollutant

carbon monoxide is reduced. Many chemists add that the oxygen atom reduces the

formation of carcinogenic polyaromatic hydrocarbons.

• Using ethanol fuels, even E10, reduces the emission of other toxins. The amountof carbon monoxide released into the air is reduced by up to thirty-two percent,

and the emission of non-regulated toxins such as butadiene and benzene isreduced by nineteen and twenty-seven percent respectively. This is beneficial to

both our environment and our health.

• Ethanol is a renewable resource because it can be produced from biomass. Other

fuels, such as oil, coal and gas, are non-renewable because the supply is notreplenished on a human timescale. This is becoming an increasingly critical issue

as deposits are exhausted and a new source of fuel must be found. Ethanol, whilehaving the advantage of being renewable, is also a hydrocarbon-based fuel.

Therefore, less drastic changes are necessary than for solar, wind and similar sources of power.

2. Use of ethanol has many economic benefits.

• Decreased reliance on foreign oil reduces vulnerability to price fluctuations, for instance, during the War on Iraq.

• Producing ethanol stimulates the economy. For instance, in Australia (where 90%

of ethanol is produced through fermentation), encouraging ethanol production

would boost the agricultural industry by opening new markets, increasingemployment in various fields and encouraging scientific research.

•Fossil fuels can be used by the petrochemical industry, rather than being burnt to produce energy.

• Co-products of ethanol production can be valuable. Distillers’ grains are used tofeed livestock because they are high in protein and fibre, and low in fat. These are

high value feeds for which there is currently high demand and low supply. Carbon

dioxide is also produced, which can be sold to soft drink manufacturers. Plants

such as “Amaizing Energy” already have the capacity to market this gas.



3. An infrastructure for ethanol is already established. While not as extensive as the

infrastructure for the distribution of petroleum, a substantial production and

distribution infrastructure is already present in Australia. This could be expanded toadapt to a growing demand for ethanol as a fuel.

4. Massive quantities of wasted starch, sugar and cellulose could be used to produce

ethanol. This would have the benefit of not using arable lands and of utilising waste

products, thus reducing landfill. However, as yet this is only a possibility, currently being researched by independent, government and fuel companies’ scientists.

Disadvantages of ethanol as a fuel:

1. The production of ethanol has negative environmental implications:

• Vast quantities of arable land would be needed for the mass production of ethanolsince technology is not at this stage capable of distilling ethanol from waste

products. Monoculture (growing only one crop in an area) destroys biodiversity;

breaks up soil structure; causes soil erosion, deforestation and – if in coastal areas – salinity; the use of fertilisers and pesticides is toxic to fauna and flora, and may

collect in waterways and groundwater. This is the reason that scientists are

experimenting to find a method of using waste products to produce ethanol.

• The distillation process produces large quantities of stinking wastes and certain

toxins. It is difficult to dispose of these wastes, and their effect arguablycounteracts other environmental benefits of ethanol. Research is currently

underway to increase the efficiency of distillation.

• Using ethanol as a vehicle fuel produces more of certain toxins. When ethanol is

used instead of petroleum, it increases the output of acetaldehyde, formaldehyde,

nitrogen oxides and various other potentially toxic, non-regulated emissions.

2. Ethanol is not yet an economically viable alternative.

• Ethanol has a comparatively low heat of combustion per gram. It produces only30kJ/g compared to (for example) octane at 42.0kJ/g. Therefore, more fuel must

combust to produce the same amount of energy. Fuel economy is reduced andlarger quantities of fuel must be transported and distributed. Consequently, the

costs for consumers, transporters and distributors increase s, making ethanol an

unpopular and arguably uneconomical alternative.

• Engines which are not designed to run on ethanol are damaged by ethanol blends.Fuels with a higher proportion of ethanol than E10 can cause corrosion of metal

parts, damage to rubber parts and increased knocking (due to the different octanerating). Engines must be adjusted to run on ethanol, or use E10 fuels.

• Ethanol is not yet economically viable to produce. The planting, fertilizing,irrigating and harvesting of the crops is quite costly, and there is always the risk of

poor harvests and hence, lowered production of ethanol. The fermentation process

yields only a fifteen percent alcohol concentration before the yeast dies, so

expensive distillation techniques are necessary. Furthermore, existinginfrastructure would have to be considerable expanded to produce adequate

quantities of ethanol, while engines would need to be adapted to run on this



alternative fuel. Therefore, there would be massive initial costs and then higher expenses.

Current uses of ethanol:

Ethanol plants are being built all over the world: China, Canada Spain, Thailand,the USA Germany, India and Brazil, many of the world’s most powerful economies, are

all massively expanding their production of ethanol. If all recently announced ethanol programs are implemented, ethanol production will reach thirty-one billion litres by2006: it was under twenty billion in 2001. The number of vehicles running on E10, E85

or even pure ethanol is on the rise, thanks to media and public demand for a ‘greener’

fuel.Because of its many useful properties, ethanol is used for a variety of purposes,

including as a solvent for toiletries, cosmetics, inks, coatings, cleaners and

pharmaceuticals; to produce various chemical intermediates (such as ethyl acrylate,glycol ethers and ethyl acetate); and to be added to alcoholic beverages. Significantly,

ethanol is more often being produced to be used as a fuel. To prevent this ethanol being

drunk, additives such as gasoline are necessary.

Due to the extensive scientific research and experimentation, the environmental benefits and cost-effectiveness of ethanol are constantly increasing. It has achieved

success as an acknowledged potential alternative fuel.

Production of Ethanol by Continent in 2001

It seems that many of the arguments for and against the use of ethanol as a fuel

are contradictory. On the one hand, it reduces the production of certain toxins; on the

other, different toxins form in larger quantities. There is the possibility that ethanol could be distilled from wastes, but as yet our technology is not adequate so large quantities of

agricultural land are required. These contradictions simply prove that arguments can be

offered both in favour of and against ethanol as a fuel.

Ethanol has potential as an alternative energy source, with many long-termenvironmental and economic advantages. However, the short-term difficulties and

expenses of introducing ethanol as a vehicle fuel or major energy source make this an

unlikely step in the immediate future. Extensive research and experimentation is



developing increasingly environmentally friendly and economically practical method to

produce and use ethanol.

1109497255 2004 chemistry assessment task sarah colenbrander

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