For years, waste vegetable oil from restaurant fryers has been processed into fuel for diesel engines. As a fuel, biodiesel is non-toxic, biodegradable, safe to handle and inexpensive. However, manufacturing and engineering technology chairperson Ahmed Elsawy, along with undergraduates Justin Wood, Jared Slayton, Seth Parrott and doctoral candidate Chinyere Mbachu, has developed an improved process for distilling biodiesel fuel. Their innovation has resulted in a form of biodiesel that burns cleaner, combusts better and offers better fuel economy.
“I tend to think in terms of environmental consciousness,” said Elsawy, “and want to move toward a green campus whenever possible. I encourage my students to ‘think green’ as well, and here we’re turning a waste product into something useful.”
The waste vegetable oil involved in this project comes directly from TTU’s food service contractor, Chartwells.
Most biodiesel fuel is waste vegetable oil that has been filtered, but not refined much past that point, hence the familiar French-fry smell in the exhaust of vehicles running on biodiesel. That conventional method for converting waste oil to fuel is time-consuming, involves a human operator to monitor the system, and requires an extra step of chemical titration for each batch produced.
The process developed by Elsawy and his team involves heating the waste oil to separate out contaminants, evaporate water and reduce viscosity. From that point, an additive of methanol and lye is introduced, separating the glycerin content from the oil. An ultrasonic processor is then used to speed up the mixing process, followed by a dry wash that helps filter out the last of any impurities. Any end product that appears cloudy is then filtered and processed again.
What ElSawy and his team envision is a greener campus, with recycled cooking oil being used for diesel equipment.
“The developed unit will provide diesel fuel for campus use, then [we can] sell the surplus to the community at a competitive price, probably in the range of $1.30 to $1.50 per gallon,” said ElSawy. “Furthermore, this project can be used to recycle cooking oil from local restaurants, and animal fats from local meat processors. The team was successful in achieving these project goals.”
The fuel that results is purer than most biodiesel – 95 percent purity vs. 80 percent. The Programmable Logic Controller that governs the various steps also helps cut processing time by more than half, while minimizing the amount of operator interaction involved. If this method for producing biodiesel is adopted on a large scale, it could mean one more step toward disconnecting America’s dependency on fossil fuels.