Piedmont Biofuels Brewtour

A few weeks after the HKF visit I traveled a bit south of Chapel Hill to Piedmont Biofuels Coop in Pittsboro, NC. Every Sunday and Wednesday they give out free tours to anyone interested at 1 pm. It’s also a potluck, so bring some potato salad and enjoy the food and conversation. For $50 bucks you can be a member and bring your car by anytime to fill up with biodiesel at their locations in Pittsboro, Durham, or Carborro. You also can go to Tuesday night brewing sessions. Matt Rudolf, Executive Director of Piedmont Biofuels leads the tours.

It was a dull rainy day when we went, but we were joined by a crowd of at least 15 others, and many members of the coop where outside working in the fields (Piedmont Biofuels has also sorts of sustainable projects other than biofuels, including organic gardening, biofuel wastewater treatment, and hay-bale insulated barns). Everyone was in chipper moods and was ready to learn, Matt was glad to help.

Piedmont Biofuels collects large amounts of waste vegetable oils from local restaurants, and lets them sit for a long period of time so that the water and other wastes form layers that can be removed from the quality oil. They skim a little of the top for the floaty pieces stuck on the oil, drain the water off the bottom (water inhibits the transesterification process), and uses the good stuff in the middle.

Methanol is stored locked away in a separate shelter; a great idea when dealing with such a potentially harmful chemical. Also, they have a large crane capable of picking up heavy barrels of oil or whatever else needs to be lifted, since a 55 gallon drum of oil can way 550 lbs or more.

The methoxide mixing chamber is a HDPE cylindrical bottomed tank, where just like HKF methanol is sprayed onto a basket of KOH and dissolved. The reactor is made of stainless steel; oil is pumped in and heated to a constant 115º F. Then methanol is slowly pumped in using a TEFL pump (nearly explosion proof) and circulated for 2 hours. The increased temperature makes a much higher quality biodiesel than it would be if it wasn’t heated. The resulting biodiesel is then gravity settled to remove the glycerin and other waste products, which is placed in a compost pile to degrade naturally.

Then the crude biodiesel is pumped into another chamber. Instead of water washing, Piedmont Biofuels uses Magnesol, MgSO₄, to clean up the biodiesel. Magnesol is a powder that will clump to impurities and sink to the bottom of the tank. Magnesol also absorbs any water that may be present. The Magnesol is then removed, the biodiesel is filtered down to 5 um, and Piedomont Biofuels has their finished product. Using Magnesol cuts the production time for a batch of biodiesel in half, and the Magnesol waste can then be composted and removed without creating hundreds of gallons of wastewater.

Piedmont Biofuels was a really great place to explore because everyone there is constantly conducting experiments, finding the correct ways to optimize the biodiesel production process. They also showed concerned with the whole life cycle of the process, not just the biodiesel, but all the byproducts and waste generated, and hoped to make the process as ecologically friendly as possible. I was really impressed, and Matt was a fantastic tour guide. For more information on Piedmont Biofuels, visit their open house tour or their webpage: http://www.biofuels.coop/.

A big special thanks to Matt Rudolf for his friendly demeanor and vast biodiesel knowledge which he kindly shares to anyone interested.