Students hit on more efficient, bubbly way of making biodiesel
By GRACE CHUA
SINGAPORE Polytechnic (SP) student Kenneth Lai spent the better part of his final year hauling jugs of waste cooking oil to school from his Jurong West neighbourhood.
His labour - mercifully, using a classmate's car - was not wasted: At the end of the year, Mr Lai, 19, and two classmates had come up with a way to make biodiesel production from waste oil much more efficient.
Waste oil can be turned into a form of biofuel, one of the many fuels derived from plants or other living organisms, and is touted as an alternative energy source which can reduce the world's fossil-fuel consumption and carbon emissions.
But it cannot be used as it is be-cause waste cooking oil will wreck an ordinary diesel engine. It must first be filtered to get the burnt food bits out, then broken down into smaller fatty acids. A catalyst chemical called sodium hydroxide speeds up the reaction.
But these fatty acids can combine with sodium hydroxide to form clumps of soap, so biodiesel production becomes less efficient.
Under the supervision of School of Chemical and Life Sciences senior lecturer Andrew Kon and SP's Technology Development manager Desmond Lim, the students tested various methods of mixing the waste oil more evenly.
After observing bubbles in a fish tank, they hit upon the idea of bubbling air through the oil in a tall, column-like tank, to mix it more evenly with the sodium hydroxide.
The size and speed of bubbling - and thus the degree of mixing - can easily be controlled.
Mr Allan Lim, chief executive of Alpha Biofuels, which turns waste cooking oil into biodiesel, said: "If they can make it work in the lab, it would be interesting to see if they can scale it up."
He is not connected with the SP project. On a commercial scale, biodiesel plants have to work with thousands of litres of oil at a time. For example, Alpha Biofuels produces about 200 tonnes per month.
At the moment, the SP students' system can handle 10 to 12 litres of oil at one go. Next, the school aims to find a commercial partner to help scale up the system, or offer consultancy services for biodiesel manufacturers.
SP's Mr Lim pointed out that Singapore's biofuels landscape is growing fast.
For example, Finnish refiner Neste Oil has a massive plant here that can handle 800,000 tonnes of the fuel a year.
