There’s nothing here about the energy balance, which is worrisome when you read the details of the process.

But, presuming that is OK, then this might be attractive. Like all petro-alternatives, the problem is scale—most people have no feel for the sorts of immense quantities of oil we blow through every day and, therefore, no intuition about how unlikely it will be that anything like the current system can be maintained once peak oil is clearly apparent.

(The moral issue of industrial farming of chickens is a whole ‘nother thing, but seeing as how industrial animal husbandry doesn’t seem to trouble some people now, I expect they will be even less troubled by it later.)

If the resultant fuel was used wisely–such as dedicated to helping farmers by ensuring they have the fuel necessary for running their machines, rather than given over to try and maintain the two-cars-in-every-driveway model–then this might be a nice breakthrough.

Research: Supercritical Method of Converting Chicken Fat Into Biodiesel
Submitted by News Account on 19 December 2007 – 11:39am. Energy

Chemical engineering researchers at the University of Arkansas have investigated supercritical methanol as a method of converting chicken fat into biodiesel fuel. The new study also successfully converted tall oil fatty acid, a major by-product of the wood-pulping process, into biodiesel at a yield of greater than 90 percent, significantly advancing efforts to develop commercially viable fuel out of plentiful, accessible and low-cost feedstocks and other agricultural by-products.

“Major oil companies are already examining biodiesel as an alternative to petroleum,” said R.E. “Buddy” Babcock, professor of chemical engineering. “With the current price of petroleum diesel and the results of this project and others, I think energy producers will think even more seriously about combining petroleum-based diesel with a biodiesel product made out of crude and inexpensive feedstocks.”

Under Babcock’s guidance, Brent Schulte, a chemical-engineering graduate student in the university’s College of Engineering, subjected low-grade chicken fat, donated by Tyson Foods, and tall oil fatty acids, provided by Georgia Pacific, to a chemical process known as supercritical methanol treatment. Supercritical methanol treatment dissolves and causes a reaction between components of a product – in this case, chicken fat and tall oil – by subjecting the product to high temperature and pressure. Substances become “supercritical” when they are heated and pressurized to a critical point, the highest temperature and pressure at which the substance can exist in equilibrium as a vapor and liquid. The simple, one-step process does not require a catalyst.

Schulte treated chicken fat and tall oil with supercritical methanol and produced biodiesel yields in excess of 89 and 94 percent, respectively. With chicken fat, Schulte reached maximum yield at 325 degrees Celsius and a 40-to-1 molar ratio, which refers to the amount of methanol applied. The process also produced a respectable yield of 80 percent at 300 degrees Celsius and the same amount of methanol. At 275 degrees Celsius and the same amount of methanol, the process was ineffective. Ideal results using tall oil fatty acid were achieved at 325 degrees Celsius and a 10-to-1 molar ratio. At 300 degrees Celsius and the same amount of methanol, the conversion produced a yield of almost 80 percent. Again, at 275 degrees Celsius, the process was ineffective.

. . .

“The supercritical method hit the free fatty-acid problem head on,” Babcock said. “Because it dissolves the feed material and eliminates the need for the base catalyst, we now do not have the problems with soap formation and loss of yield. The supercritical method actually prefers free fatty acid feedstocks.”

Biodiesel is a nonpetroleum-based alternative diesel fuel that consists of alkyl esters derived from renewable feedstocks such as plant oils or animal fats. The fuel is made by converting these oils and fats into what are known as fatty acid alkyl esters. The conventional processes require the oils or fats be heated and mixed with a combination of methanol and sodium hydroxide as a catalyst. The conversion process is called transesterification.

Most biodiesel is produced from refined vegetable oils, such as soybean and rapeseed oil, which are expensive; they generally account for 60 to 80 percent of the total cost of biodiesel. Due to these high feedstock prices, biodiesel production struggles to be economically feasible. Currently, as Babcock alluded, biodiesel cannot compete with petroleum diesel unless the per-gallon price of diesel remains higher than $3. For these reasons, researchers recently have focused efforts on less refined and less-expensive feedstocks as a more viable competitor to conventional diesel. . . .

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