Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Environmental challenges: Biofuels
Transcript
Biofuels Developed by Beth Morgan Dept. of Plant Biology Types of Biofuel: Ethanol Ethanol can be produced using: Corn stover Sugar cane bagasse Hybrid poplar Switchgrass Miscanthus Biggest Suppliers Increase in Production Making Ethanol From Seed 1. Grow and collect grain. 2. Grind kernels into meal. 3. Heat and enzymes convert starch to sugar. 4. Anaerobic respiration by yeast. 5. Alcohol (ethanolº is distilled out of mixture. Ethanol Energy Yield Making Ethanol From Cellulosics: Cell Wall Breakdown Making Ethanol From Cellulosics 1. Collection, storage & transportation to refinery. 2. Dirt & debris removed from material and then shredded into small particles. 3. Heat, pressure or acid treatment. Enzymes in solution are used to breakdown cellulose, hemicellulose to sugars. Lignin is removed. 4. Syrup of sugars is filtered from solids. 5. Anaerobic fermentation by bacteria to produce alcohol (and carbon dioxide). 6. Further enzymatic breakdown of cellulose and lignin. 7. Anaerobic fermentation by bacteria to produce alcohol (and carbon dioxide). 8. Alcohol is distilled. 9. More water removed. 10. Stored for distribution and use. Types of Biofuel: Biodiesel Bio-diesel can be produced using: Algae Jatropha tree Palm oil Camelina Making Biodiesel Waste Vegetable Oil Lye Methoxide Methanol WVO Washed Biodiesel Water Biodiesel Glycerin Washed Biodiesel Water Biodiesel Biodiesel BioFuel from Vegetable Oil Pros: Energy Yield Pros: Energy Yield For every unit of fossil energy used in the entire biodiesel production cycle, 3.2 units of energy are gained when the fuel is burned, or a positive energy balance of 320 percent. Pros: Energy Yield Fuel Gasoline Diesel Energy yield 0.805 0.843 Net (loss) or gain (19.5%) (15.7%) Ethanol Biodiesel 1.34 3.2 34% 320% (gain is from photosynthesis) Pros: Reduced Emissions Emissions of major air pollutants from diesel engines Cons: Loss of Land for Food Production Loss of Rainforests Water Use Increases Soil Fertility Poplar trees Switchgrass harvest in the Netherlands Soybean harvest Price of Corn Food vs. Fuel?
