Biofuels are an increasingly admired source of alternative energy in times of unstable gas prices.
Production of biofuels, however, is quite slow -- about an hour to produce a few hundred milliliters in a laboratory, which is not efficient, especially when demand is high. That is why researchers at University of Missouri’s Agricultural Engineering department are working on a unique way to speed up the production process to mere minutes, allowing supply to meet that high demand.
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Ultrasound Speeds up Biodiesel Production
When gas prices skyrocket, people look to alternatives that will get them off oil. Biofuels, fuels made from biological sources such as plants, vegetables and even algae, are one such option. Making a biofuel is a complicated and time-consuming process that ultimately drives up the costs. Assistant Professor Bulent Koc of the University of Missouri may have a solution. He’s investigating how ultrasound technology, the same kind used to image fetuses in a mother’s womb, can speed up biofuel production. If it works, it could lead to higher supply in the marketplace at a potentially lower cost.
The conventional process of making a biofuel involves mixing the oil derived from the plant with an alcohol, usually methanol. During mixing, the alcohol reacts chemically with the oil, stripping away fatty acids that make the oil too thick for use in a fuel tank as is. The mixing process usually takes an hour to produce just a few hundred milliliters of biofuel because the mixers are not very efficient.
Koc, an agricultural and biological engineer, had used ultrasound technology as part of his research in the past to look at different properties of food. For example, he figured out concentrations of alcohol in wine by measuring the velocity of the sound waves within the wine and how long they took to bounce back. When he came to the University of Missouri, the agricultural engineering department required him to focus on energy rather than food, so he applied it to biofuel production.
The ultrasonic wave process works like this: a desktop computer-sized device, known as an ultrasound generator, drives an ultrasound transducer, the machine that makes ultrasonic waves pass through a mixture of methanol and vegetable oil. These waves heat the mixture of oil and alcohol, creating bubbles that eventually burst. The bursts release high pressure and temperature, which break the molecular bonds in the fluids, allowing the two liquids to mix at a much faster pace. After the molecular bonds break, the fatty acids release, producing the by-product glycerin, and the remaining molecules recombine into a biodiesel.
“We wanted to see the effects of ultrasonic energy on glycerin separation time, that means reducing the production time of biodiesel.
Unlike the conventional process that takes an hour to produce a few milliliters, this process takes just five minutes to make about the same amount.
Leon Schumacher, a collaborative researcher who has worked with biofuels since the early 90’s and is the department head of Agricultural Engineering at the University of Missouri, believes one of the main problems of biodiesel production is its cost. He’s hoping that the use of ultrasonic waves can help make biodiesel cheaper for both consumers and producers.
“It does cost money to convert to a biodiesel. It’s not a free process, and the end result is that if we can minimize that, that would be a huge win for the biodiesel industry.”
Koc has used the technique on different vegetable and cooking oils, including soybean, sesame, peanut, and canola oils, with notable success. The main challenge with using ultrasonic waves, however, is that the machine transmitting the waves heats up quickly and can become damaged. Koc thinks this problem could be fixed with a machine that circulates a cooling liquid around the ultrasonic device.
“You would have a cooling jacket around the ultrasonic transducer. This way you could maintain the temperature of the device itself so that it doesn’t overheat or get damaged.”
Koc has not yet made the cooling device. Currently, Koc and Schumacher are testing the ultrasonic biodiesels in diesel engines.
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