Education Standards
Student Observation Sheet
"Growing" Renewable Biofuel
Overview
How can we manufacture environmentally friendly fuels using renewable sources? In this lesson, students will explore the process used to produce biodiesel from soybeans and test the efficiency of their fuel.
Overview
Essential Question
- What process can we use to manufacture renewable fuel?
Learning Objectives
- Students will be able to provide the definition of a renewable fuel.
- Students will be able to explain how biodiesel fuel is made from vegetable oil.
- Students will be able to assess the efficiency of biodiesel to determine quality.
Career Connections
- Biochemist
- Biosystems Engineer
- Renewable Energy Specialist
Equipment and Materials
Equipment (per group)
- 200mL Beaker (1)
- Graduated Cylinder (1)
- Glass Jar w/ Lid (1)
- Hot Plate (1)
- Magnetic Stirrer (1)
- Glass Thermometer (1)
- Electronic Scale (1)
- Weigh Boat (1)
- Serological Pump (1)
- Serological Pipette Tips (2-3)
- Putt Putt Boats w/ Wicks (1)
- Lighter (1)
- Chemical Hood (under ideal circumstances)
Consumable Materials
- Corn Oil
- Vegetable (Soybean Oil)
- Methanol (HEET Gas-Line Antifreeze)
- Sodium Hydroxide or Potassium Hydroxide
- Distilled Water
*CAUTION - Methanol is a dangerous substance that causes irritation when it comes in contact with skin, and has highly flammable fumes. Always wear gloves and goggles when working with this chemical and keep away from any sparks or flames. Work under a chemical hood or other well ventilated space if possible.
Per Student
- Pen/Pencil
- Lab Notebook
- Safety Goggles
- Disposable Gloves
Lesson Plan
Background Information
Biodiesel is a renewable fuel made from any biologically based oil, and can be used to power any diesel engine. Biodiesel has become a widely used fuel source around the world and is recognized as an environmentally friendly alternative to petroleum diesel. It is made commercially from soybeans and other oilseed crops in an industrial setting, but it is also commonly made in home shops from waste fryer grease.
Dr. Rudolf Diesel first demonstrated his diesel engine, which ran on peanut oil, to the world in the early 1900's. The high compression of diesel engines creates heat in the combustion chamber, and thus does not require highly flammable fuel such as that used in gasoline engines. The diesel engine was originally promoted to farmers as one for which they could "grow their own fuel." The practice of running engines on vegetable oil become less common over time as petroleum diesel became cheap and readily available.
Interest Approach
Facilitate a discussion with students about the last time they went to fuel up their vehicles. Ask them what type of fuel they dispensed into their vehicle and what their reasoning was behind using that specific type of fuel. Use the attached powerpoint to show an image of a fuel pump and then ask students if they know what the numbers mean. More than likely students know that there is ethanol in their fuel which is manufactured from corn, but what students may not know is that there is another type of renewable fuel called biodiesel which is manufactured using soybeans. The second image in the powerpoint was taken at a fuel pump used for dispensing different blends of biodiesel.
Experimental Procedure
*Prior to the activity, students need to put on their safety goggles and a pair of disposable gloves.
Part 1 - Synthesis of Renewable Diesel (Day 1)
- Measure out 150mL of vegetable oil or corn oil into a 200mL beaker.
- Place the beaker onto a hot plate and warm your chosen oil to 50°C.
- One member of each group should use a glass thermometer to routinely monitor the temperature to ensure that the oil does not overheat. *Proceed to Step 3 while waiting.
- Measure 60mL of methanol into a graduated cylinder under a chemical hood and then quickly transfer it into a glass jar. Cap the methanol bottle and seal the glass jar.
- Use an electronic scale to weigh out 1.5g of KOH (potassium hydroxide) into a weigh boat, and then quickly transfer it into the glass jar with the methanol.
- Reseal the jar and then shake for a few minutes until all of the potassium hydroxide has dissolved. *The mixture in the glass jar is now called methoxide.
- Once the mixture inside the glass jar has become methoxide and the oil sample is up to 50°C, add the warmed oil to the methoxide along with a magnetic stir bar and loosely seal the glass jar.
- CAUTION - Be certain that the oil is not over 60°C, or the methoxide may boil.
- Set the magnetic stirrer to high speed and stir for approximately fifteen minutes.
- Alternatively, tighten the lid on the glass jar and shake vigorously for fifteen minutes.
- Allow the mixture to sit for 24 hours.
Your jar now contains biodiesel, glycerin, mono- and di- glycerides, soap, methol and lye. The glycerides are all oil-soluble, so they will reside predominantly in the upper, biodiesel layer. The thin layer of glycerin, which is water-soluble, will sink to the bottom.
Part 2 - Washing Renewable Diesel (Day 2)
- Use a sterological pipette to drain the glycerin from the renewable diesel into a waste flask.
- Use a sterological pipette to slowly add 20mL of distilled water down the side of the glass jar.
- Pick up the jar and gently rotate end over end for approximately five minutes. (*Do not shake the jar!)
- Allow the jar to settle for approximately ten minutes or until the mixture has separated into two layers.
- Remove the soap/glycerin waste from the bottom layer using a sterological pipette and dispose of into a waste flask.
- Add more distilled water and keep repeating the sloshing and draining process until the end of class.
- Each time the mixture is 'rinsed', there will be less soap - keep washing and diluting until the water becomes clear and separates out quickly.
- After draining the last of the wash water away, allow the biodiesel to 'dry' exposed to open air overnight.
- In general, the better the washing was conducted, the faster the fuel will clear.
- Answer Analysis Questions 1 and 2 on the 'Student Observation Sheet'.
Part 3 - Testing the Biofuel (Day 3)
Performance is an important factor when manufacturing fuel of any type. Putt putt boats may be used to test the length of time that a specific volume of fuel burns as well as the speed at which the boat travels.
- Obtain a putt putt boat with a metal basin and candle wick prior to beginning the activity.
- Use a pipette to transfer 1mL of biodiesel from the topmost layer of the glass jar to the metal basin where the candle wick rests.
- Place the putt putt boat into a basin of water and then light the candle wick using a lighter.
- Use a timer to record how long the putt putt boat is able to be propelled in the water.
- Record your data in Table 1.
- Compare your data with that collected by other groups.
- Return all materials to their designated areas and pour out water into a sink.
- Answer Analysis Questions 3-5 on the 'Student Observations Sheet'.
Conclusion/Check for Understanding
After the conclusion of student data collection and cleaning up of materials, bring the class together and have students discuss their results in small groups. Discussion should be focused on the performance of their biodiesel and what factors they believe may have an influence on performance. Have students share their results with the whole class and have them hypothesize what they may have been able to change to improve their fuel efficiency.
Extension Activity
Yield Test - To test for glycerine yield, the contents of the glass jar can be poured into a graduated cylinder, and the relative volume of each layer measured. Comparison can be made between the results from different batches of oil, or by changing variables between batches of the same oil.