In the Green Room: Chuck's biodiesel explainer, part two

Transcript

Chuck: Tell us, how do you make biodiesel? Is it a simple thing? Is it very complicated?
Rob: Ah, it’s simple to do. It’s difficult to do it right. But basically there’s not a whole lot to it. What we do is we go out and we collect the fryer oil. So we’ve got a truck that’s basically a big vacuum cleaner on wheels. We vacuum up the used fryer oil from the containers behind the restaurant. We’ve got a lot of independent and locally owned restaurants and that’s sort of our bread and butter, for sure, is working with the independent restaurants. We also have some chains. We have, are working with about 50, 60 Chick-fil-A’s in the Atlanta area.

Chuck: Oh, that’s cool.

Rob: They’ve been very supportive. Ted’s Montana Grills, they committed a long time ago, been big supporters of our program. We bring it back to our facility where we filter out all the French fries and chicken bones and food bits that are gonna be in there. We dehydrate it, so we get the water out of it. We’re interested in just the oil. Then what we basically do is we heat up the oil and we react that oil, we mix it with methanol, a small amount of methanol and a chemical catalyst. We use potassium hydroxide, which is very similar to lye that you use as drain cleaner, so a little bit of that material mixed with methanol, introduce it to the oil, mix that up at an elevated temperature for a while. So what happens is a reaction occurs where the glycerin breaks off. The methanol molecules bond to these chains, give you methyl esters which is biodiesel, and the glycerin portion, which is heavier and denser, settles to the bottom of the tank. So we stop. We turn everything off. We let it sit for a while. And then we’ll notice it’ll be glycerin on, you know, the bottom portion will be glycerin. We’ll drain off that glycerin. Now we’ve got methyl esters on top. We evaporate off the methanol and reuse it, so the excess we recycle. We pull the water off and dispose of the water and we absorb the soaps and residual catalyst so that doesn’t make it into the fuel tank. After that purification stage, we’re done. We’ve got biodiesel ready to go in the tank.

Chuck: Voila.

Rob: Voila.

Chuck: And I’d like to point out that it’s a musician that figured all this out.

Rob: Well, I didn’t figure it out at first, but I learned how to do it. It’s not exotic technology and that’s one of the great things about it.