DF 7 & DF 8 DF 7 & DF 8 Changing the fuelChanging the fuel

Current problemsCurrent problems

Aromatic hydrocarbons up to 40% of petrolAromatic hydrocarbons up to 40% of petrol

Give higher CO, CxHy & NO emissionsGive higher CO, CxHy & NO emissions

Some may cause cancer, e.g. benzeneSome may cause cancer, e.g. benzene

Volatile components evaporate, causing Volatile components evaporate, causing ozone formation & photochemical smogozone formation & photochemical smog

Other considerationsOther considerations

Butane and aromatic hydrocarbons have Butane and aromatic hydrocarbons have high octane numbers – so must be high octane numbers – so must be replaced by other high octane componentsreplaced by other high octane components

Oxygenates offer high octane and less Oxygenates offer high octane and less pollution pollution

Which oxygenates?Which oxygenates?

MTBEMTBE

MethanolMethanol

EthanolEthanol

MTBEMTBE

May be carcinogenicMay be carcinogenic

Banned in parts of USABanned in parts of USA

MethanolMethanol Burns cleanlyBurns cleanly Octane number 114Octane number 114 CheapCheap

BUT - BUT - Does not mix readily with petrolDoes not mix readily with petrol Very hygroscopic – absorbs water Very hygroscopic – absorbs water

vapour, leading to corrosion of vapour, leading to corrosion of engine partsengine parts

ToxicToxic

EthanolEthanol

Burns cleanlyBurns cleanly

Octane number 111Octane number 111

Readily produced by fermentation Readily produced by fermentation

The future?The future?

Hydrogen?Hydrogen?

Can be produced by electrolysis of waterCan be produced by electrolysis of water

This needs energy, but solar energy or This needs energy, but solar energy or wind power could be used, thus replacing wind power could be used, thus replacing fossil fuel use with use of renewable fossil fuel use with use of renewable energy sourcesenergy sources

• Renewable Energy: Is enough being Renewable Energy: Is enough being done?done?

• The government has released its Energy The government has released its Energy White Paper. The paper announced plans White Paper. The paper announced plans to radically cut the pollution linked to to radically cut the pollution linked to global warming. global warming.

• The paper suggestsThe paper suggests that that It also It also announced the running down of nuclear announced the running down of nuclear power stations, which currently supply power stations, which currently supply about 25% of all UK electricity. about 25% of all UK electricity.

• 10% of electricity should come from 10% of electricity should come from renewable power such as wind and wave renewable power such as wind and wave energy by 2010. energy by 2010.

•November 2003

•The first British off-shore wind farm opens off the Welsh coast

•16 more are planned

How would hydrogen be used?How would hydrogen be used?

Hydrogen can be storedHydrogen can be stored

It can be used in the internal combustion It can be used in the internal combustion engine engine

A fuel cell in the car would use hydrogen A fuel cell in the car would use hydrogen to generate electricityto generate electricity

The Fuel Cell is a device which converts The Fuel Cell is a device which converts hydrogen and oxygen into electricity. It hydrogen and oxygen into electricity. It achieves this using a process which is the achieves this using a process which is the reverse of electrolysis of water reverse of electrolysis of water

As a result of hydrogen and oxygen combining As a result of hydrogen and oxygen combining to make water, electricity flows.to make water, electricity flows.

Problems with hydrogenProblems with hydrogen

A gas with a small relative formula massA gas with a small relative formula mass

A large volume is needed to power a A large volume is needed to power a vehiclevehicle

If hydrogen is compressed, a very strong If hydrogen is compressed, a very strong fuel tank is needed (this would be heavy).fuel tank is needed (this would be heavy).

Assignment 12Assignment 12

Have a go!Have a go!