Biofuels are produced from biomass. Biomass includes living organisms such as plants, trees and crops, as well as half of all trash. The major potential of biomass is for production of liquid transportation fuels. These fuels include ethanol and methanol, two alcohol fuels made from corn, wheat and other crops, and methane, a colorless, odorless and flammable gas made from waste. Ethanol, methanol and methane offer an attractive alternative to petroleum-based gasoline and diesel fuels. There are more than 185 million vehicles in the U.S., and these vehicles are responsible for two-thirds of the nation’s total oil consumption. The quantity of biomass currently available could produce enough liquid transportation fuel to replace all the gasoline we currently use in these vehicles. By the end of the decade, technological advancements will make these fuels as affordable and easy to use as today’s petroleum-based gasoline and diesel fuels.
PROJECT #1 WHAT IS THE EFFICIENCY OF ETHANOL PRODUCTION FROM VARIOUS SOURCES?
Reference A procedure for preparing ethanol is given in many organic chemistry laboratory manuals. For example, see Pavia et al. Introduction to Organic Laboratory Techniques, Saunders College Publishing, 3rd ed., 1988 “Ethanol from Sucrose,”
- Compare the relative yields of ethanol produced from various sources: table sugar, grain crops, fruits, cellulose, corncobs, corn silage, etc. One way to do this is to use rate or total volume of carbon dioxide production as an indirect indicator of ethanol production. For a more accurate measurement, contact the chemistry department at a college/university to see if someone would let you use a gas chromatography unit. Demonstrate the energy of the distillate fuel by soaking it in cotton wool and setting it alight. Don’t forget to run a control.
2. Develop a procedure for determining the percentage of alcohol you can prepare from the various sources. One method might be to use potassium dichromate standards. This substance is the basis for some commercial kits for determining alcohol levels before and after consuming alcoholic beverages.
3. Investigate optimum temperature for fermentation.
4. Investigate aerobic and anaerobic conditions for producing ethanol.
5. Investigate methods of quantifying ethanol production from one or more sources.
Caution Methane gas is explosive when mixed with air! Extreme care must be taken when generating large quantities of methane. Don’t attempt this project in a laboratory or home basement if flames from a laboratory burner or furnace are around. Be sure to purge the system of air before attempting to burn methane!
Materials Source of biomass (e.g. animal dung. garbage, food wastes, etc.).
Equipment : Methane generator as shown below.
Resources (I) Williams, D.I. and D. Anglesea, 1978, Experiments on Air Pollution, Hove, England: Wayland Publishers Limited, p. 50-51. (2) “Larry J. Romeesberg Cooks with Bio-gas.” December 1975, from Adventures in Alternative Energy, Popular Science.
Ideas to Study
1. Compare the volume of methane gas produced from equal amounts of biomass. Fill the jar with biomass and make sure it is well pressed down to remove as much air as possible. Biomass must be moist (add water if necessary). Be sure that the delivery tube is above the biomass in the generator. The best incubation temperature is 36-37°C.
2. Investigate the effects of temperature on methane generation. CAUTI0N: do not use a laboratory burner of any type to raise the temperature of the contents in the jar .To raise of lower the temperature, place a pan of hot or ice cold water beneath the gas generator. You made need to devise a safe way to keep the temperature warmer or colder than the optimum temperature.
Equipment Laboratory balance and a calorimeter (see diagram below):
Safety Work in a well-ventilated area. Be extremely careful of burns because a lot of heat energy will be generated. Reference A college level general chemistry text will have a chapter on thermo chemisty that will be useful in seeing some of the calculations needed to do in this project.
Ideas for Study
1. Conduct preliminary tests to determine the best size of plant material to test. Compare the heat energy in a given quantity of plant materials (e.g., peanuts, pecans, walnuts, castor beans, sunflowers, corn, and milkweed). Calculate he amount of calories per gram. Use equal volumes of water in the test tube for each test and record the beginning and ending temperatures.
2. You can improve your results by using a bomb calorimeter. Check with the chemistry department at a college or university.
3. Determine the usable heat energy that could be produced on an acre of land if certain crops were raised. Choose peanuts and sunflowers, for example. This would require one to know the caloric value (cal/g) and the amount of biomass produced per unit area.
4. Devise a procedure for extracting the oil from the plant and determine the oil’s heat energy. For example, milkweed contains latex, an unsaturated hydrocarbon.
Materials Use the set up for the calorimeter as described in Project #3, but use an alcohol burner as the source of heat. Caution Alcohols are very flammable. Work in the science laboratory under supervision of your teacher or another adult.
Ideas for Study
1. Compare the heat energy from burning alcohols (e.g., methanol, ethanol, propanol, rubbing alcohol, etc). Measure the weight of alcohol before and after the burning alcohol raises the temperature of 100 mL (equals 100 g) of water at least SOOC. Calculate the calories per gram for each alcohol tested.
2. Devise a more efficient procedure that reduces heat loss. Determination of heat values and efficiencies as related to cost would be important to know. How could these fuels be used?
Caution Handle fertilizers, pesticides, and plant hormones with care. Procedure Grow plants from seeds in cups or pots. Measure height and width daily or measure dry weight after several days or weeks. Use a variety of plant types -food and nonfood, grasses, and weeds. Weigh soil to see how much “earth” is used.
Ideas to Study
1. Investigate plant growth utilizing one of these factors. Keep in mind each factor can be a study in
a. Type of light.
b. Amount of light.
c. Spacing of seedlings.
d. Soil type.
e. Frequency of watering.
f. Fertilizer vs. no fertilizer.
g. Pesticide vs. no pesticide.
h. Salt content of water [use varying concentrations of salt water and measure dry weight after days or weeks].
i. Plant hormone vs. no plant hormone. [Apply plant hormone with aspirator or a perfume bottle or small paint brush, but apply evenly. Biomass can be determined as fresh weight and dry weight (dry in oven) for 24 hrs at 90″C -include roots.]
j. Orientation of a single seed when planted. [Replicate the orientation of seeds planted several times. Remember the greater the sample size the more reliable the data. Plant each seed at the same depth as the others. Make sure that the light source is equally distributed on each tray containing the seeds.]
k. Depth seed is planted in soil.
l. Effect of increased amount of carbon dioxide (see diagram below and handle dry ice with care). [plants should have a minimum of 5-6 leaves and be of approximately equal size. Calculate total leaf at the beginning and end of the experiment for each plant. If dry ice is used, consider that carbon dioxide is heavier than air and also consider the temperature effect on plants. Use same soil provide equal amounts of water and light. Could use sodium bicarbonate and monitor pH.]
m. Effect of temperature on the rate of photosynthesis [Assemble the apparatus as shown in the diagram below and take care assembling the apparatus, specifically the insertion of a glass tube into a rubber stopper. Be careful of the hypodermic syringe. Many general biology lab manuals give directions for measuring gas production in photosynthesis. Don’t forget to set up a control (minus the plant). Keep light intensity the same and remember that most light sources produce heat.