Class18

Class18 - Chemistry 83 Current Energy Technologies Fossil...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemistry 83 Class18 1 Current Energy Technologies http://www.countercurrents.org/world_energy.jpg Fossil fuels (coal, oil, natural gas) serve as the source for ~88% of current world energy production
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chemistry 83 Class18 2 http://resources.edb.gov.hk/biology/english/images/environment/carbon_cycle2.jpg Fossil fuels are produced very slowly (millions of years) by the carbon cycle Heat (45%) Transportation (25%) Electricity (30%) There are three broad uses of energy
Background image of page 2
Chemistry 83 Class18 3 Science for production of heat from fossil fuels • Combustion is reaction with O 2 • Combustion converts chemical energy to heat energy: Fossil fuel + O 2 CO 2 + H 2 O; H H = BE(reactants) - BE(products) • Highlighted term always dominates since the products of combustion each have two strong bonds: CO 2 (2BE C=O = 374 kcal) and H 2 O (2BE O-H = 220 kcal) H < 0 for combustion of all fossil fuels making them good sources for heat energy • Average H for fossil fuels is -9 kcal/g Energy can also be obtained from directly or indirectly from biomass by combustion Solar energy Stoker et al, Energy, Scott Foresman,IL, 1975, 285 Advantages Disadvantage (Biomass)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chemistry 83 Class18 4 Tro, 220 1 Natural gas provides the most heat/g of all fossil fuels since it has largest (number of C-H bonds/C): C n H 2n+2 ; (2n+2)/n = 2+2/n 2 Hydrogen is likely replacement for fossil fuels for storing energy due to high heat of combustion (3 times that of natural gas). 1 2 http://www.nykline.co.jp/engliSH/seascope/200604/image/photo_01.gif Oil is used for transportation (easy to store) C 1 -C 4 C 5 -C 13 C 10 -C 16 C 15 -C 25 C 20 -C 70 >C 70
Background image of page 4
Chemistry 83 Class18 5 http://www.howstuffworks.com/engine.htm Mixture of gasoline (C5- C13) and air is ignited by a spark from spark plug (K). Explosion forces piston downward and causes crankshaft and ultimately the car wheels to rotate. Technology: internal combustion engine converts chemical energy heat energy mechanical energy http://www.ueet.nasa.gov/StudentSite/engines.html Aircraft burn jet fuel (C10-C16) in jet engine Brings air in Raises air pressure Raises air T and P Provides energy for fan and compressor Adds by- pass air Provides thrust Spark plug ignition
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chemistry 83 Class18 6 http://auto.howstuffworks.com/diesel.htm Trucks and trains burn diesel fuel (C15- C25) explosively in diesel engine Diesel engine has
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/19/2011 for the course CHEM 83 taught by Professor Bonk,j during the Fall '08 term at Duke.

Page1 / 18

Class18 - Chemistry 83 Current Energy Technologies Fossil...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online