Alternative Fuels

Ethanol

Ethanol

• Ethyl Alcohol

• Grain alcohol

• Solution with water – 95% alcohol fuel

• Fermentation produces a mash

• Alcohol has a lower boiling point than water

• Evaporates & condensed in a coil

Term: Ethanol

• Wheat or corn kernels are ground in a hammermill to expose the starch.

• The ground grain is mixed with water, cooked briefly and enzymes are added to convert the starch to sugar using a chemical reaction called hydrolysis.

• Yeast is added to ferment the sugars to ethanol. • The ethanol is separated from the mixture by

distillation and the water is removed from the mixture using dehydration

Economic Problems with Ethanol

• Major bankruptcies in largest producers

• Cost more to produce than it sells for even with subsidized corn

• Corn-based ethanol is a transition to cellulosic ethanol

• 60% less energy dense than gasoline

Engine Problems with ethanol

• Ethanol alcohol is an excellent SOLVENT– Dissolves rubber, certain types of fiberglass.– Many engine hoses of older engines are not resistant to alcohol.

• Ethanol will ABSORB WATER • Ethanol ignites at a higher temperature, compared to

conventional non-alcohol gasoline, causing damage to pistons.

• E10 can not be added to a tank or pump that contains oyxygenators MTBE or ETBE.

• Over 10% ethanol will cause damage to most conventional engines.

Carbohydrate Review

• Sugar needed for ethanol

• Cellulose or Lignin

• Very difficult to break the bond between the glucose molecules – requires expensive pretreatments

Cellulysis

• Breaking the bonds that connect the individual glucose molecules– Enzymes– Concentrated Acids– Steam– Microbes

• Solving this step is where the research and the money is right now.

Sources of Cellulose

• Switchgrass – grows on poor quality soil

• Corn stover – leftover corn stalks from corn grain harvesting

• Waste paper

• Yard wastes

• Timber waste

Crops grown for cellulose

• Switch grass, Poplar trees, etc

• The US uses 142 billion gallons of gas/year = 200 billion gallons of ethanol

• 1 acre of poplar trees can produce 650 gal of ethanol

• Would take 307 million acres to grow enough cellulose

• 3X larger than the entire corn crop

Solutions?

• Where will our motor fuel come from in 10 to 20 years?

Today

• Start biodiesel

• Tomorrow - Clean the biodiesel

Homemade Biodiesel

• Uses very toxic chemicals• Must use goggles & gloves• Make methoxide: methanol (Heet) & lye (NaOH)

– extremely toxic– & corrosive– & exothermic

• Add methoxide to warm vegetable oil.• Shake for 5 seconds every 10 minutes for 1 hour• Let settle overnight• Clean & separate it tomorrow