Various methods of producing biodiesel

A recent article by Jennifer Bogo in Popular mechanics tells how Dave Hubbard makes his own biofuel; he makes this biodiesel from the vegetable oil used at a nearby tavern for cooking wings.  Fatty acids from burned food must be removed from the oil before fuel is available for use.  These acids are converted to glycerin using a solution of sodium hydroxide (NaOH (aq)) to titrate.  A small additional amount of NaOH is needed to catalyze the reaction of “virgin bean oil.”  According to Hubbard, most restaurants produce chemically consistent cooking oil if they change it on a regular basis.  Conversely, other restaurants that do not change their oil frequently produce oil that either is no longer usable for biofuel or conversion of it to biofuel is no longer cost-effective.  That oil which is suitable for conversion to fuel is mixed with methanol (45 gallons of oil with 9 gallons methanol), kept at a temperature of 120ْ F, and stirred for 45 minutes using a modified drill press.  The final yield is typically around 40 gallons of biodiesel and 5 gallons of glycerin.  Hubbard leaves the mixture sitting overnight.  During this period, the glycerin precipitates out.  The biodiesel is then washed and ready to use.  Hubbard claims that the total cost of materials, heat, and power add up to a grand total of 50 cents per gallon.  He sells this fuel to local farmers and uses it in his diesel Volkswagen Jetta.

An article by Chris Ladd, another writer for Popular Mechanics, a slightly more sophisticated, albeit much more expensive, method of producing biodiesel is being developed in California by LS9 Inc. and Amyris Biotechnologies.  These companies are engineering the genetic make-up of bacteria to produce hydrocarbons rather than triethylglycerides.  Amyris first determined the properties that make good biofuels and are now genetically modifying E. coli and other micro-organisms (yeast and bacteria) to produce these fuels.  With approximately 2 million tons of sugar (used as feed for the bacteria), Amyris claims to be able to produce 30 million gallons of diesel.

According to Ladd, J. Craig Venter, who was involved with the mapping of the human genome, is currently working with LS9 on designing bacteria to produce hydrocarbons from atmospheric CO2.  LS9 recently purchased a “state-of-the-art production facility.”  They are now updating it and should have it ready to produce between 50 and 100 million gallons of fuel by next year.  However, this fuel will be more conventional in production methods, using “renewable raw materials.”  This plant is located on the opposite side of the country in southern Florida.  Here, they will also use sugar cane as a feedstock; but, this feedstock will be feeding fuel, not bacteria.  Nothing is mentioned on the company’s page for the facility about the use of bacteria in the method being developed by Venter.


Comments are closed.

%d bloggers like this: