Gasoline

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Gasoline

  1. 1. Gasoline
  2. 2. Chemistry of Petroleum <ul><li>Petroleum is composed of organic compounds containing Carbon and Hydrogen </li></ul><ul><ul><li>Hydrocarbon Molecules </li></ul></ul><ul><li>CH 4 Methane, the simplest Hydrocarbon </li></ul>CH 4 + 2 O 2  2 H 2 0 + CO 2 + Energy
  3. 3. More Hydrocarbons 2 Carbon Atoms ETHANE (C 2 H 6 ) 3 Carbon Atoms PROPANE (C 3 H 8 ) 4 Carbon Atoms BUTANE (C 4 H 10 ) And so on. Five Carbon Atoms give you PENTANE (C 5 H 12 ) Six Carbon Atoms give you HEXANE (C 6 H 14 ) Seven give you HEPTANE (C 7 H 16 ).
  4. 4. The World’s Favorite Hydrocarbon Octane: Eight Carbons (C 8 H 18 ). The main ingredient in gasoline
  5. 5. <ul><li>Use the formula below to determine the number of Hydrogen Atoms busing the number of Carbon atoms (n). </li></ul>C n H 2n+2 Hydrocarbons
  6. 6. Chemistry of Petroleum <ul><li>Temperature and number of carbon atoms determine the form of petroleum </li></ul><ul><li>At Ordinary surface temperatures: </li></ul><ul><ul><li>Less than 5 Carbon atoms </li></ul></ul><ul><ul><ul><li>Gas </li></ul></ul></ul><ul><ul><li>5 to 15 Carbon Atoms </li></ul></ul><ul><ul><ul><li>Free-Flowing Liquids. </li></ul></ul></ul><ul><ul><ul><li>CRUDE OIL </li></ul></ul></ul><ul><ul><li>Greater than 15 </li></ul></ul><ul><ul><ul><li>Thick viscous liquids to waxy solids. </li></ul></ul></ul>
  7. 7. Crude Oil <ul><li>Liquid petroleum recovered directly from the well is called crude (unrefined or unprocessed) oil. </li></ul><ul><li>Crude oil is comprised of a mixture of hydrocarbon molecules </li></ul><ul><li>Light (sweet) Crude </li></ul><ul><ul><li>low S impurities </li></ul></ul><ul><ul><li>Can easily be refined to gasoline </li></ul></ul><ul><ul><li>Produced in Nigeria, U.S. Gulf States, Canada  </li></ul></ul><ul><li>Heavy (sour) Crude </li></ul><ul><ul><li>high S impurities </li></ul></ul><ul><ul><li>Difficult to refine to gasoline </li></ul></ul><ul><ul><li>Produced in Saudi Arabia, Mexico, Venezuela, Iraq </li></ul></ul>
  8. 8. Petroleum Refining <ul><li>An oil refinery is an industrial plant where crude oil is processed and refined into more useful petroleum products. </li></ul>Every barrel of crude oil can be refined into many products or fractions.
  9. 9. Crude Oil Fractions <ul><li>Petroleum gas (1-4 Carbons) </li></ul><ul><ul><li>used for heating, cooking, making plastics </li></ul></ul><ul><li>Naphtha (8 Carbons) </li></ul><ul><ul><li>dry cleaning solution; intermediate that will be further processed to make gasoline </li></ul></ul><ul><li>Gasoline (8 Carbons) </li></ul><ul><ul><li>motor fuel </li></ul></ul><ul><li>Kerosene (12 Carbons) </li></ul><ul><ul><li>fuel for jet engines and tractors; starting material for making other products </li></ul></ul>
  10. 10. Crude Oil Fractions <ul><li>Gas Oil or Diesel (16 Carbons) </li></ul><ul><ul><li>used for diesel fuel and heating oil; starting material for making other </li></ul></ul><ul><li>Lubricating Oil (36 Carbons) </li></ul><ul><ul><li>used for motor oil, grease, other lubricants </li></ul></ul><ul><li>Heavy gas or Fuel oil (44 Carbons) </li></ul><ul><ul><li>used for industrial fuel; starting material for making other products </li></ul></ul><ul><li>Residuals (80 Carbons) </li></ul><ul><ul><li>coke, asphalt, tar, waxes; starting material for making other products </li></ul></ul>
  11. 11. Components of a Refinery
  12. 12. Fractional Distillation <ul><li>The hydrocarbons in crude oil have different boiling points, according to the number of carbon atoms their molecules contain and how they are arranged. </li></ul><ul><li>Fractional distillation uses the difference in boiling point to separate the hydrocarbons in crude oil. </li></ul><ul><li>The fractionating column is cooler at the top than the bottom, so the vapors cool as they rise. </li></ul>
  13. 13. Fractional Distillation
  14. 14. Fractional Distillation <ul><li>Vapors condense onto a tray when they reach the part of the column which is cooler than their boiling point. </li></ul><ul><li>As the last gases from the bottom of the column pass through the holes in a tray, any lighter hydrocarbons still in the condensed liquid are boiled off, and rise through the column. </li></ul>
  15. 15. Chemical Processing <ul><li>Very few of the components come out of the fractional distillation column ready for market. </li></ul><ul><li>Many of them must be chemically processed to make other fractions. </li></ul><ul><ul><li>For example, only 40% of distilled crude oil is gasoline </li></ul></ul><ul><li>After distillation, one fraction can be changed into another by two methods of chemical processing: Cracking and Unification </li></ul>
  16. 16. Cracking <ul><li>Cracking breaks large chains into smaller chains. </li></ul><ul><li>After various hydrocarbons are cracked into smaller hydrocarbons, the products go through another fractional distillation column to separate them. </li></ul>
  17. 17. Unification <ul><li>Unification combines smaller hydrocarbons into larger ones </li></ul><ul><li>A reformer combines chains to make naphtha into gasoline. </li></ul><ul><li>A significant by-product of this reaction is hydrogen gas, which is then either used for hydrocracking or sold. </li></ul>
  18. 18. Refineries and the Environment <ul><li>The refining process releases numerous different chemicals into the atmosphere; consequently, there are substantial air pollution emissions. </li></ul><ul><li>Due to pollution problems there is strong pressure to prevent the development of new refineries, and no major refinery has been built in the U.S. since 1976. </li></ul><ul><li>However, many existing refineries have been expanded during that time. </li></ul>
  19. 19. <ul><li>Illinois leads the Midwest in crude oil refining capacity with four refineries. </li></ul><ul><li>About 5.2% of U.S. Petroleum is refined in Illinois and is mainly supplied by the Tar Sands on Canada. </li></ul>Illinois Refineries
  20. 20. Cost of Gasoline <ul><li>While it isn't represented in the diagram, some of the actual money you spend at the pump does go to the service station. </li></ul><ul><li>Service stations add on a few cents per gallon. </li></ul><ul><li>Gas prices mainly rise when there are changes in refining and the price of crude oil </li></ul>
  21. 21. Gasoline (4-Stroke) Engine <ul><li>Burns fuel and air in enclosed space producing hot gases </li></ul><ul><li>Allows heat to flow from hot engine to cold outside air </li></ul><ul><li>Converts some of this heat into useful work </li></ul><ul><li>Example of a Heat Engine </li></ul>
  22. 22. Gasoline (4-Stroke) Engine <ul><li>The four strokes of the cycle are induction, compression, power, and exhaust.  </li></ul><ul><li>Each corresponds to one full stroke of the piston, therefore the complete cycle requires two revolutions of the crankshaft to complete. </li></ul>
  23. 23. Induction Stroke <ul><li>During the induction stroke, the piston moves downward, drawing a fresh charge of vaporized fuel/air mixture. </li></ul><ul><li>The carburetor mixes the fuel and air. </li></ul>
  24. 24. Compression Stroke <ul><li>As the piston rises the poppet valve is forced shut by the increased cylinder pressure.  </li></ul><ul><li>Flywheel momentum drives the piston upward, compressing the fuel/air mixture. </li></ul><ul><li>Compressed Fuel is easier to ignite. </li></ul>
  25. 25. Power Stroke <ul><li>At the top of the compression stroke the spark plug fires, igniting the compressed fuel.  </li></ul><ul><li>As the fuel burns it expands, driving the piston downward. </li></ul><ul><li>Chemical energy converted to thermal energy converted to mechanical energy. </li></ul>
  26. 26. Exhaust Stroke <ul><li>At the bottom of the power stroke, the exhaust valve is opened by the cam/lifter mechanism.  </li></ul><ul><li>The upward stroke of the piston drives the exhausted fuel out of the cylinder. </li></ul>
  27. 27. Gasoline (4-Stroke) Engine <ul><li>Power stroke: heat in, work out </li></ul><ul><li>Exhaust stroke: heat out </li></ul><ul><li>Some of the extra work out is used during induction and compression </li></ul><ul><li>Some heat lost to conduction and convection in and around the engine. </li></ul>
  28. 28. Gasoline and 4-stroke Engines <ul><li>A 4-stroke engine is designed to run on a refined mixture of hydrocarbons from C7–Heptane and C8–Octane. </li></ul><ul><li>This mixture is called Gasoline </li></ul><ul><li>C7 and C8 vaporize at temperatures below the boiling point of water. </li></ul><ul><ul><li>That's why if you spill gasoline on the ground it evaporates very quickly. </li></ul></ul>
  29. 29. Octane Rating <ul><li>The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. </li></ul><ul><li>Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane </li></ul><ul><li>Most gas stations offer three octane grades: </li></ul><ul><ul><li>regular, usually 87 octane </li></ul></ul><ul><ul><li>mid-grade, usually 89 octane </li></ul></ul><ul><ul><li>premium usually 92 or 93. </li></ul></ul><ul><li>The ratings must be posted on bright yellow stickers on each gasoline pump. </li></ul>
  30. 30. Knocking <ul><li>Knocking occurs when gas ignites by compression rather than because of the spark from the spark plug. </li></ul><ul><li>Problems </li></ul><ul><ul><li>Annoying </li></ul></ul><ul><ul><li>Reduces efficiency </li></ul></ul><ul><ul><li>Damages engine </li></ul></ul><ul><li>Heptane handles compression very poorly </li></ul><ul><li>Octane handles compression very well </li></ul>
  31. 31. Solutions to Knocking <ul><li>Increase the octane rating of the gasoline </li></ul><ul><li>This costs $$$$$ </li></ul><ul><li>Requires chemical processing techniques to be done numerous times </li></ul><ul><li>Almost impossible to refine 100% octane. </li></ul><ul><li>Most car engines today are designed to run effectively on an octane rating of 87. </li></ul>
  32. 32. Gasoline Additives <ul><li>During WWI, it was discovered that you can add a chemical called tetraethyl lead to gasoline and significantly improve its octane rating. </li></ul><ul><li>Lower octane grades of gasoline could be made usable by adding this chemical. </li></ul><ul><li>This led to the widespread use of &quot;ethyl&quot; or &quot;leaded&quot; gasoline. </li></ul>
  33. 33. Tetraethyl Lead (TEL) <ul><li>TEL was cheap to manufacture. </li></ul><ul><li>Most oil companies could process TEL at their refineries. </li></ul><ul><li>This increased profits for the oil company. </li></ul><ul><li>However……. </li></ul>
  34. 34. Tetraethyl Lead (TEL) <ul><li>Due to the combustion of TEL in gasoline, the Earth became covered in a thin layer of lead. </li></ul><ul><li>Even glacial ice at the north pole recorded an alarming increase of lead during the mid to late 1900s. </li></ul>
  35. 35. Health Risks of TEL Exposure <ul><li>Acute Exposure in Adults </li></ul><ul><li>Blindness </li></ul><ul><li>Brain Damage </li></ul><ul><li>Kidney disease </li></ul><ul><li>Cancers </li></ul><ul><li>Death </li></ul><ul><li>Low Level Exposure in Children </li></ul><ul><li>Lowered IQ </li></ul><ul><li>Reading and Learning Disablities </li></ul><ul><li>Impaired hearing </li></ul><ul><li>Hyperactivity </li></ul><ul><li>Impaired Growth </li></ul>
  36. 36. Removal of TEL <ul><li>In the early 1970s, catalytic converters were required in vehicles by the Clean Air Act to reduce smog forming pollutants. </li></ul><ul><li>Lead from gasoline additives clogs a catalytic converter. </li></ul>Note: Leaded Gasoline was not phased out due to health concerns directly from the lead!
  37. 37. Removal of TEL <ul><li>Leaded gasoline was phased out in the United States staring in 1973 due to the Clean Air Act. </li></ul><ul><li>Illegal to sell leaded gasoline for on-road vehicles as of January 1, 1996. </li></ul><ul><li>Fuel containing lead may continue to be sold for off-road uses, including aircraft, racing cars, farm equipment, and marine engines until 2008 </li></ul>
  38. 38. Lead is Still a Problem Most of the 7 million tons of lead burned in the gasoline in the United States in the twentieth century remains --- in the soil, air, and water and in the bodies of living organisms.
  39. 39. MTBE <ul><li>MTBE has been used in U.S. gasoline at low levels since 1979 to replace TEL to increase its octane rating and help prevent engine knocking. </li></ul><ul><li>A hydrocarbon molecule that is created at a refinery from methanol. </li></ul><ul><ul><li>Big money maker for petrochemical companies </li></ul></ul><ul><li>Gasoline can contain as much as 10 percent to 15 percent MTBE. </li></ul>
  40. 40. MTBE Use and Releases
  41. 41. MTBE <ul><li>The main problem with MTBE is that it is thought to be carcinogenic and it mixes easily with water. </li></ul><ul><li>If gasoline containing MTBE leaks from an underground tank at a gas station, it can get into groundwater and contaminate wells. </li></ul><ul><li>Twenty seven states have passed laws to ban MTBE in certain areas. </li></ul>

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