When we make biodiesel we create an annoying “cocktail” of co-products. The cocktail includes methanol, free fatty acids, and glycerin. We recover the methanol using heat. And we break apart the free fatty acids and the glycerin phase using an acid wash in our glass lined reactor. We take the free fatty acids and burn them in boilers. And we use our boiler heat to power most of our bio-refinery. In doing so we have managed to turn off some of our electrical heaters–which improves the carbon footprint of our operation.
Burning free fatty acids in a boiler is not trivial. We had to get a unit that had change the spray pattern, and when it did not work as promised we had to customize the system ourselves. Little things, like pump seals and gaskets, and an electric eye which looks for a petroleum colored flame. It wasn’t a problem, really, after we pulled the fire box and spray painted it to “fake out” the electric eye.
We putzed around with making our boilers work for six months. We ended up pre-heating, and homogenizing, and wrestling with the system, but we now have it spinning like a top. It’s all custom. But it works beautifully. And we deliver a million BTUs an hour into our process.
We’ve been selling these systems. Free fatty acids are cheap as a fuel source. This picture is of a system we built for Screech Owl Greenhouse, in which he will use free fatty acids for district heating of a big greenhouse project.