Fossil Fuels and Biofuels powerpoint slide deck

Fossil Fuels and Biofuels slides

1. Fossil Fuels and Biofuels U3 AOS1 Chapter 1.2

2. Energy transformations Fuels contain energy in the chemical bonds. When chemical reactions occur energy can be transformed from one form to another. Energy efficiency – measure of the % of energy converted into useful energy

3. Electricity production Electricity from coal – 35% efficient due to heat loss when burning fuel C(s) + O 2(g)  CO 2(g) Δ H = -32kJ g -1

4. Electricity production Electricity from natural gas CH 4(g) + 2O 2(g)  2H 2 O (l) + CO 2(g) Δ H = -55.6kJg -1 Approx 40% efficient Fewer particulate emissions Less CO 2 per unit of energy

5. Electricity production Electricity from Biogas – works the same way as natural gas but biogas has less energy released as it has a smaller % of methane in the fuel Often found in small scale generators instead of large power plants

6. Fuel for transport Most fuel for transport is derived from crude oil Liquid petroleum gas – LPG Petrol Kerosene Petrodiesel

7. Petrol Petrol is s mixture of hydrocarbons including octane C 8 H 18 (l) + 25/2 O 2 (g)  8CO 2 (g) + 9 H 2 O (l) Δ H = -2450 kJ mol -1 or 47.8 kJg -1 Efficiency is approx. 25%

8. LPG LPG is s mixture of hydrocarbons including propane C 3 H 8 (g) + 5 O 2 (g)  3CO 2 (g) + 4 H 2 O (l) Δ H = -2220 kJ mol -1 or 50.5 kJg -1 Conversion to use LPG is expensive and the canister to store it under pressure takes up space

9. Bioethanol Ethanol can be blended in cars to make up to 10% of the petrol (E10) C 2 H 5 OH (l) + 3O 2 (g)  2CO 2 (g) + 3H 2 O (g) Δ H = -1367 kJmol -1 or 29.7 kJg -1 Energy content is approx. 62% of petrol so a larger mass or greater volume of fuel is needed to provide the same energy

10. Environmental impact Emissions from fuel combustion Other emissions Environmental impact of sourcing fuels

11. Renewability Coal Cruse Oil Natural gas Biofuels

12. Comparisons of fuels