Paul Painter¹ and Lucas McConnell²
¹Materials Science and Engineering and The Energy Institute
²Renewergy Corporation, Erie PA.
Presently, biofuels in this country usually means one of two things, ethanol (in the U.S. principally produced from corn) or biodiesel (largely from oilseeds or yellow grease). However, large-scale production of these fuels will inevitably lead to the displacement of croplands used to produce food and there will clearly be a limit on the quantity of ethanol and biodiesel that can be obtained from these sources. Furthermore, although both biodiesel and ethanol have a number of attractive properties (in addition to being derived from a renewable source), they are not without problems (lower energy content, clogging of fuel lines and filters because of their ability to dissolve gums and other deposits, etc.).
It would clearly be advantageous if a cheap, relatively simple method were available to produce a predominantly hydrocarbon fuel (i.e., largely decarboxylated oils) from feedstocks that contain high contents of free fatty acids. One source that we wish to particularly focus on is algae, for the purposes of this project being produced on by Renewergy Corporation. Renewergy has developed a proprietary, “aeroponic algalculture” technique that uses a fraction of the water needed by conventional processes and a simple way of increasing surface area for light and CO2 absorption.
In preliminary work, we have applied Kolbe electrolysis to the processing of algal oil. Kolbe electrolysis of fatty (alkanoic) acids was the first known electrochemical synthesis. Faraday had originally observed (in 1834) that hydrocarbons are formed upon electrolysis of acetate solutions, but it was H. Kolbe who performed the first detailed investigations of the reactions of carboxylic acids at an anode some fifteen years later. Essentially, the reaction involves the electrochemical oxidative decarboxylation of carboxylic acid salts that leads to radicals, which can then combine to form simple hydrocarbons. We have found that a number of side reactions occur, but these can be advantageous in producing biofuels.