Deep inside the University of Connecticut’s chemical engineering building in Storrs, Professor Richard Parnas and a team of students quietly monitor a murky brown emulsion bubbling inside an enormous 6-inch diameter glass tube, like doctors carefully observing a patient undergoing surgery.

Moving among an array of flexible tubing and metal rods surrounding the nearly floor-to-ceiling device, Parnas keeps a watchful eye on a series of multi-colored charts blinking on a nearby laptop. The display represents the real-time readings of a high-tech fiber-optic probe monitoring the chemical reactions taking place inside the tube. It helps Parnas, a UConn professor of chemical, materials, and biomolecular engineering, maintain the precise recipe he needs to turn a mixture of methanol, potassium hydroxide, and waste vegetable oil into nearly pure, cheap, environmentally-friendly biodiesel fuel.

One-step process

Parnas’ patented biodiesel reactor is unique in both its simplicity and efficiency. In conventional biodiesel production, vegetable oil is converted into biodiesel fuel and glycerol, a by-product of the conversion process. Then, the glycerol must be mechanically separated from the diesel fuel, as part of a two-step process. Parnas’ reactor is different in that it uses gravity, heat, and natural chemical reactions to make the biodiesel and separate the glycerol in one step.

As the chemical reactions take place inside the giant tube, temperatures reach more than 100 degrees Fahrenheit. The glycerol starts to coagulate in opaque swirls inside the tube. Because the glycerol droplets are heavier than the biodiesel fuel, they gradually sink to the bottom, where they are siphoned off. At the same time, the biodiesel fuel floats to the top of the tube and is pumped into a holding tank, where it undergoes refinement before being mixed with petroleum-based diesel fuel and used in the University’s bus fleet.