DF 11: Other Fuels

Question 1

Why do we need fuels of the future?

Answer 1

Fuels of the future should reduce emissions, pollution and be much more economical and reduce global warming.

Question 2

What is the main alternative to the use of fossil fuels?

Answer 2

Biofuels

Question 3

What are biofuels?

Answer 3

Biofuels are fuels derived from renewable plant and animal material.

Question 4

What are the main biofuels that scientists are working on?

Answer 4

Ethanol, biodiesel and biogas

Question 5

How is ethanol made?

Answer 5

Bioethanol is made by the fermentation process of carbohydrate crops such as sugar cane

Question 6

What are the advantages of using bioethanol?

Answer 6

Bioethanol is said to be carbon neutral, this is because the carbon dioxide produced in the fermentation and combusting of the ethanol matches the carbon dioxide absorbed in growing the plant (such as sugar cane)

Question 7

What are the disadvantages of bioethanol?

Answer 7

One of the main disadvantages of bioethanol is that a huge amount of land is required to grow the amount of crops needed for the fuel, this land could be used for other purposes such as food

Question 8

Why is growing crops for bioethanol a problem in developing countries?

Answer 8

This is a problem because developed countries such as the UK will create a huge demand as they try to find fossil fuel alternatives. Developing countries may see this as a way of getting money, which means land that could be used for growing crops would be lost :(

Question 9

How is biodiesel made?

Answer 9

Biodiesel is made by chemically reducing fats and oils with an alcohol producing fatty acids and esters

Question 10

What is the process of biodiesel manufacturing called?

Answer 10

Trans-esterification

Question 11

What are the advantages of using biodiesel over diesel?

Answer 11

• Biodiesel can be made from waste oil rather than using fossil fuelled based oil, which would only go to waste in landfills (Bio gas also has this advantage)
• It is carbon neutral
• It is biodegradable if spilled
• It contains virtually no sulphur so it reduces oxides of sulphur in the emissions which can cause problems such as acid rain
• It produces less particulates, carbon monoxide and hydrocarbons than petrol and diesel

Question 12

What are the disadvantages of using biodiesel?

Answer 12

The use of biodiesel produces more nitrogen oxides than conventional fossil fuels

Question 13

What is another problem with biofuels?

Answer 13

One problem with switching from fossil fuels to biofuels in transport is that petrol car engines would have to be modified to use fuels with high ethanol concentrations = Lots of money

Question 14

Why are there negatives associated with fuels that are said to be carbon neutral?

Answer 14

There are negatives because fossil fuels are still used in the production of fuels that are carbon neutral such as in the factories that make them and in the lorry’s that transport them.

Question 15

How is biogas made?

Answer 15

Biogas is produced by the breakdown of organic waste matter

Question 16

Name the other main potential fuel of the future (its a gas)

Answer 16

Hydrogen

Question 17

How is hydrogen produced?

Answer 17

Hydrogen can be produced by the electrolysis of sea water

Question 18

When combusted, what does hydrogen produce?

Answer 18

Just water

Question 19

What are the advantages of using hydrogen?

Answer 19

• It is renewable and can be made by the electrolysis of water
• It can be stored and sent down pipelines (in much the same way that methane is)
• It can be used in internal combustion engines or in a fuel cell to generate electricity
• It produces no carbon dioxide, carbon monoxide or hydrocarbons when combusted

Question 20

What are the disadvantages of using hydrogen?

Answer 20

• It is less energy dense than petrol - so it doesn’t release as much energy per gram as petrol
• Oxides of nitrogen are still produced at the high temperatures a hydrogen internal combustion engine runs at
• Its production from water often depends on the use of electricity from fossil fuel power stations

Question 21

How can hydrogen be used?

Answer 21

Hydrogen can either be burned in a modified engine, or used in a fuel cell, (a fuel cell converts hydrogen an oxygen into water, and this chemical process produces electricity)

Question 22

What is a problem of obtaining hydrogen?

Answer 22

It takes energy to extract hydrogen from water/seawater

Question 23

What are the difficulties associated with transporting and storing hydrogen?

Answer 23

Hydrogen is highly flammable and it has to be liquified due to the low energy to volume ratio of hydrogen gas. This means building a whole new infrastructure (Chemical plants to produce the hydrogen fuel)