The document discusses different types of fuels produced from crude oil and their combustion properties. It then explains the environmental impacts of burning fossil fuels, including global warming, acid rain, and global dimming. Strategies to reduce these impacts through the use of emission control devices and alternative fuels like biodiesel and hydrogen are also summarized.

1. © SSER Ltd. Chemistry (14 - 16) Fuels (Effects of Burning)

2. Oil refineries produce large volumes of fuel to power modern forms of transport, and for many other uses. The different fuels are produced from the fractional distillation of crude oil. Petrol ignites below 0ºC Diesel ignites above 50ºC Fuel oil ignites above 100ºC Ethanol ignites above 13ºC Combustion of Fuels Produced From Crude Oil These combustion properties affect how each fuel is used... Different fuels have different sized molecules. The size of the molecules affect how easily the fuel ignites and burns, e.g.

3. Jet engines of modern aeroplanes burn light jet fuel...

4. Motorcycles burn petrol...

5. Cars burn petrol or diesel. Some are even being modified to run on biofuels such as ethanol or biodiesel...

6. Public transport would grind to a halt without diesel...

7. Trains burn diesel...

8. Power stations like this one at Immingham, next to a major oil refinery, now burn diesel fuel to generate electricity for the National Grid.

9. Large ships burn heavy fuel oil.

10. The Burning of Fuels The burning of fuels in air is called combustion. As heat energy is given out, this is an exothermic reaction. Example: methane is a fuel used in many homes... CH 4(g) + 2O 2(g)  CO 2(g) + 2H 2 O (g) + energy All fuels will burn in air (combustion) to produce carbon dioxide and water. Other chemicals products may be made, e.g. carbon monoxide, sulfur dioxide and carbon. + oxygen  carbon dioxide + water + energy methane (fuel)

11. The Complete Combustion of Methane in Air 90% Methane 5% Ethane 3% Nitrogen 1.0% Propane 0.5% Carbon dioxide 0.5% Butane Natural gas consists of...

12. For safety reasons, a sulfurous additive is combined with natural gas to give it its characteristic smell of bad eggs. Natural gas is mostly methane, so when it is combusted in air, we consider it to effectively be the combustion of methane. Natural Gas or Methane?

13. In excess oxygen, the equation for combustion of methane is: CH 4 + 2O 2  CO 2 + 2H 2 O methane oxygen carbon dioxide water The Complete Combustion of Methane in Air

14. The Complete Combustion of Methane in Air In excess oxygen, the equation for combustion of methane is: CH 4 + 2O 2  CO 2 + 2H 2 O methane oxygen carbon dioxide water

15. The photograph shows a bunsen flame where complete combustion is taking place. The Complete Combustion of Methane in Air The blue flame is characteristic of complete combustion. The air hole is fully open and so there is ample air (oxygen) supply. CH 4 + 2O 2  CO 2 + 2H 2 O methane oxygen carbon dioxide water

16. Where oxygen levels are limited, incomplete combustion occurs. This is a more complex process made up of a number of possible reactions. This word equation shows the possible products: 2CH 4 + 3O 2  2CO + 4H 2 O methane oxygen carbon monoxide water The Incomplete Combustion of Methane in Air CH 4 + O 2  C + 2H 2 O methane oxygen carbon water Incomplete combustion may have these additional reactions taking place at the same time: methane + oxygen  carbon + carbon + carbon + water dioxide monoxide

17. Many people die in their homes or whilst on holiday, as a result of carbon monoxide poisoning, due to faulty gas fires and central heating boilers - carbon monoxide is a colourless, odourless gas! Carbon Monoxide Poisoning 2CH 4 + 3O 2  2CO + 4H 2 O methane oxygen carbon monoxide water

18. The Incomplete Combustion of Methane in Air The photograph shows a bunsen flame where incomplete combustion is taking place. The air hole is closed and so the air (oxygen) supply is restricted. It is the carbon atoms that give the safety flame its characteristic yellow colour. As the electrons of the carbon atoms lose energy they emit light. CH 4 + O 2  C + 2H 2 O methane oxygen carbon water

19. Although most fuels are mainly hydrocarbons, they also contain low levels of sulfur. This means that during combustion, in excess levels of oxygen, the following reaction also takes place: S + O 2  SO 2 sulfur dioxide oxygen sulfur The sulfur dioxide, carbon dioxide and carbon particles produced by combustion are all linked to environmental problems... The Combustion of Sulfur within Fuels

20. Carbon dioxide is linked to the greenhouse effect. Increased levels of carbon dioxide are trapping the Sun’s energy, causing the climate to warm up. Sulfur dioxide is linked to acid rain. Increased levels of sulfur dioxide are turning rain water acidic, causing fish and trees to die. Carbon particles are linked to global dimming. Increased levels of carbon particles are causing more sunlight to be reflected, which reduces the total sunlight reaching the Earth. Environmental Impact Carbon Dioxide Sulfur Dioxide Carbon Particles

21. Acid Rain Acid rain is caused by burning fossil fuels, which contain small amounts of sulfur and nitrogen. During the burning, sulfur and nitrogen are converted to sulfur dioxide and nitrogen dioxide.

22. When it rains, these acids fall to the Earth as acid rain. This process decreases the pH of soil and the water in lakes and rivers, which kills trees and fish. Acid Rain Acid rain also increases the rate at which carbonate rocks and ancient buildings made of limestone, are being weathered.

23. Acid Rain Use the interactive diagram to find out more about acid rain...

24. The following Pie Chart shows the various UK contributors to atmospheric SO 2 . What can be done to reduce these emissions? Reducing Acid Rain - SO 2 Emissions

25. To reduce the levels of sulfur dioxide produced by burning fuels, a number of strategies have been adopted: Many refineries remove sulfur during the refining process allowing fuel stations to offer low sulfur fuels to their customers. Power stations are fitted with a scrubber, a device which removes sulfur dioxide... Reducing Acid Rain - SO 2 Emissions

26. A scrubber (fluid gas desulfuriser or FGD unit) is a device fitted to fossil fuel power stations, which removes the sulfur dioxide from waste gases. The FGD sprays the flue gases with a limestone/water mixture producing gypsum, which is used in the building industry. Reducing Acid Rain - Using a Scrubber

27. Reducing Acid Rain - Using a Scrubber A scrubber (fluid gas desulfuriser or FGD unit) is a device fitted to fossil fuel power stations, which removes the sulfur dioxide from waste gases. The FGD sprays the flue gases with a limestone/water mixture producing gypsum, which is used in the building industry.

28. Catalytic converters are now fitted as standard to all car exhausts. Normal car exhaust gases contain unburnt petrol, oxides of nitrogen (which contribute to acid rain) and carbon monoxide. Reducing Acid Rain - Catalytic Converters Catalytic converters, containing the transition metal platinum, cause a reaction between these polluting gases to produce harmless gases, such as nitrogen, oxygen, carbon dioxide and water vapour.

29. Catalytic Converter Move the cursor over the red circles to find out more...

30. Sources of SO 2 in the UK (1999) Discuss the data in the table... % SO 2 Produced in UK SO 2 Source 65 Power Stations 6 Domestic & Commercial 4 Other 3 Transport 10 Other Industry 12 Oil Refineries, Iron & Steel Production

31. The Greenhouse Effect Move the cursor over the diagram to find out more...

32. Greenhouse gases within the Earth’s atmosphere absorb some of this outgoing radiation and reflect it back to the Earth’s surface. As levels of CO 2 and other air pollutants increase, they trap even more of the outgoing heat radiation causing even more global warming. Some of this radiation is re-emitted from the earth as long wave radiation. About 80% of the short wave, infra red radiation emitted by the Sun penetrates the Earth’s outer atmosphere and warms the Earth. CO 2 The Greenhouse Effect CO 2 CO 2 CO 2 CO 2 CO 2 CO 2

33. Global Dimming Global dimming is caused by the burning of organic material such as fossil fuels and wood. Many sources contribute to global dimming, e.g. in power stations, car engines, burning forests and even wood for cooking. The burning releases particles of soot and ash which reflect sunlight back into space - thus preventing the sunlight from reaching the Earth’s surface. It is this effect whereby less light penetrates the atmosphere which is known as global dimming.

34. Global Dimming The soot and ash particles also trigger the formation of water droplets in clouds and cause the production of many more droplets, which increases a cloud’s reflective properties. This further increases the amount of solar radiation reflected into space.

35. Global Dimming - Summary Move your cursor over the diagram to find out more...

36. Global Warming v Global Dimming Scientists now believe that global dimming has been working against global warming. The dimming caused by pollution has reduced the effect of global warming, which would have been much worse otherwise. A worrying consequence of cleaning up pollution, is that the full effect of global warming will be felt, and the planet will warm up at an even faster rate. The effect of global dimming was clearly shown, immediately after the 9/11 terrorist attacks, after which all flights were cancelled for a few days. During this time, because there was less pollution and cloud formation, the temperature of the Earth rose significantly.

37. Reducing the Environmental Impact One suggestion is not to fly so often - perhaps we will only be allowed to go abroad once every few years or a new tax will be put on non essential flights. One flight abroad on a summer holiday produces more CO 2 per passenger than the all the rest of the annual CO 2 production allocated per person.

38. As fossil fuel supplies run out, newer types of fuels are being developed, such as biodiesel, ethanol and hydrogen. Alternative Fuels - Ethanol A supply of sugar beet, used for making ethanol.

39. This reaction is called transesterification. Biodiesel can be made from rapeseed, soybean, palm oil or even recovered cooking oils. Biodiesel is used as a fuel in diesel engines. However, if this biofuel is dissolved in petrol or ethanol, it can be used in petrol engines. Straight vegetable oil (SVO) can be used in place of ordinary diesel. Vegetable oil can be improved as a fuel by reacting it with methanol, using sodium hydroxide or potassium hydroxide as a catalyst. This produces biodiesel. Alternative Fuels - Biodiesel

40. Alternative Fuels - Hydrogen Hydrogen can be produced from either water or natural gas. It is then combined with oxygen inside a fuel cell to produce electricity, which can power a car. Move your cursor over the diagram to find out more...

41. Alternative Fuels - Hydrogen Hydrogen can be produced from either water or natural gas. It is then combined with oxygen inside a fuel cell to produce electricity, which can power a car. However, the production of electricity (non-renewable energy sources) used to produce the hydrogen (from water) releases large volumes of CO 2 . The hydrogen is also difficult to store safely. Move your cursor over the diagram to find out more...

42. Alternative Fuels: Hydrogen This concept car with a hydrogen engine may be the way forward for land transport. It certainly is modern technology...

43. Energy Use Environmentalists argue for energy conservation, to reduce the effects of global warming. Move your cursor over each student to see their points of view...

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