What do you get when you mix eggshells, turkey bones, canola oil, and alcohol?
What Culver Girls Academy junior Mufei Li (Shenzhen, China) cooked up was a cheap, sustainable way to produce biodiesel fuel. Li recently won three awards during the Hoosier Science and Engineering Fair with her project “Using eggshells and turkey bones as catalysts to produce biodiesel through transesterification.”
She won second place overall for Best Use of Chemistry during the competition, which was conducted virtually due to the coronavirus restrictions. She also received awards for Excellence in Environmental Science and Sustainable Development.
She advanced after receiving a blue ribbon at the Northern Indiana Science and Engineering Fair conducted at the University of Notre Dame in February.
Li worked with science instructors Jackie Carrillo and Jessica DeNapoli on the project, which will double as her Honors in Science project. She also created a slide presentation and five-minute video, giving a detailed explanation behind the process.
The transesterification of vegetable oils, animal fats or waste cooking oils is the process behind conventional biodiesel. In the transesterification process a glyceride reacts with an alcohol in the presence of a catalyst forming fatty acid alkyl esters and an alcohol.
“I used canola oil as a source of triglyceride and methanol as a source of alcohol,” Li said. “The eggshells and turkey bones acted as a catalyst because I calcinated them and the calcium carbonate in them turned into calcium oxide under high heat.”
For her experiment, Li ground the eggshells and turkey bones into powder form. They were selected because they are a cheap source of calcium and do not dissolve when mixed with methanol. She used two temperature settings, 25 and 37 degrees Celsius, while running the experiment to compare which catalyst and temperature combination provided the best results.
Her results showed the eggshells served as a better catalyst than the turkey bones because they contain a higher concentration of calcium carbonate. The highest level of biodiesel was produced when using the eggshells at 25 C (just 77 degrees Fahrenheit).
Theoretically, biodiesel is carbon neutral because the amount of carbon dioxide it produces upon combustion is roughly equal what is taken in by the plants by photosynthesis, Li explained. Production of the fuel sometimes involves emitting carbon dioxide, due to the “thermal decomposition reaction of calcium carbonate.”
Still, she added, it is closer to “carbon neutral” than traditional fossil fuels.