Refining of Petroleum Petroleum is a complex mixture of many sized mostly linear hydrocarbon molecules First step is separating out different size groups –Fractional distillation –A fraction is a portion of the crude oil in which the molecules fall in a range of sizes or boiling points.
Petroleum Refining Straight-run gasoline is low quality –Octane rating of ~55 Catalytic reforming –Uses a catalyst –Converts straight chain HC’s to branched ones and aromatics and other unsaturated HC’s –Boosts octane rating
Reformulated Gasoline Add oxygen containing compounds –Ethanol –Methanol –MTBE –ETBE Required in high pollution areas –In Utah?
Oil Spills Many natural ones – California coast Can harm the environment, at least short term Long term, nature has ways of cleaning up –Mostly consumed by bacteria and oxidized. Other sources – –Normal tanker operations, tanker accidents –Blow-outs, changing oil
Coal Largest supply 250 - 1500 years worth Different types of coal - age Much more complex
Coal 88% of coal burned in US generates electricity Dirtier burning – ash, sulfur, etc. Not very mobile Best bet: Gasification or Liquifaction –Break up into smaller molecules and add hydrogen –Central removal of pollution –Held back by economics –Called “clean coal technologies”
Coal Mining Dangerous –Over 100,000 killed in US in last century –Getting safer all the time Strip mining – “stripping” off covering and scooping out coal –Less dangerous –Harder on the environment
Alternatives Methanol –½ the energy content of gasoline –½ the cost of gasoline –Very corrosive to the fuel system –M85 and M100 –E85 and E100 –FFV’s
Alternatives Electricity – secondary source (converted) –36% of energy in the US is used to produce electricity –Average efficiency – 31% Lost? –More mobile and clean Garbage, burn or ferment Geothermal Wind Temperature difference in oceans Biomass, burn or ferment Solar