an old water heater tank can be adapted to make a safe and inexpensive biodiesel homebrewing apparatus. An HDPE carboy (white jug in photo) or other tank can become a passive small-scale methanol-catalyst mixer, and an inexpensive centrifugal pump (blue motor in photo) from Harbor Freight tools mixes the two liquids to enable the biodiesel reaction to take place. After a day of settling, the glycerol byproduct can be drained out fairly well- the tanks have a wine-bottle-bottom profile, with a drain at the ‘pointed’ edge, so separation of two liquids can be reasonably clean. The processor costs about $150 in plumbing and electrical, and about a day or less of work. The tank can be an ancient lime-crusted one scavenged from a dump, or can be bought new for about $200 more.
March 13, 2007
