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How To: Fuel Your Car With Thanksgiving Leftovers
by Maggie Koerth-Baker - March 20, 2007 - 7:59 AM

turkey_legs.jpgQuestion: What’s greasy, grimy, and surprisingly useful?

Answer: Turkey guts…and a lot of other stuff, too. It just depends on how you process it.

If you’re reading this, you’re probably hip to the concept that Americans (and pretty much everybody else in world) have a bit of an oil addiction and that, unlike some things you could get yourself addicted to, the supplies aren’t limitless. So, wouldn’t it be great if we could make it ourselves? Produce oil just like the Earth does—through pressure and heat—only faster? No, we haven’t been painting in an unventilated room again…


It turns out that DIY oil is not only possible, it’s a reality. As you read this, a factory near Carthage, Missouri is turning tons of waste from a nearby turkey slaughterhouse into diesel fuel and fertilizer. How? A little thing called thermal depolymerization.

See, oil is made naturally when carbon (usually in the form of dead plants and animals) gets buried under tons of earth and is then smooshed and heated by the movement of techtonic plates. Needless to say, this takes a while. But, in 2003, a company called Changing World Technologies perfected a way to duplicate this process in a factory in a fraction of a fraction of the time—as little as 15 minutes in some cases. Better yet, because of the way the process works, it’s far more energy efficient than any other available method of producing biofuel, yielding 100 British Thermal Units of energy for every 15 BTUs spent in production.

But wait, this gets better. Not only can thermal depolymerization turn turkey into black gold, it can do the same thing with just about any carbon-containing substance—from raw sewage, to old car tires, to cast-off computers. Annnnd, what doesn’t get made into oil ends up as other handy products, such as the aforementioned fertilizer or useful industrial chemicals.

So why haven’t you heard of this? Frankly, we have no idea. Part of the problem, though, is that when Congress drew up regulations to give biofuel-producing companies a tax break in 2005, they wrote the legislation in a way that excludes thermal depolymerization. This makes it difficult to get investors and to compete with the tax-break-advantaged. Nevertheless, we like thermal depolymerization—with every fiber of our gizmo-loving, tree-hugging being—so we’re hoping that if we explain more about how this works, maybe you’ll spread the gospel.

250px-Turkeys_on_path.jpg

YOU WILL NEED
Pressure
Heat
Some sort of carbon-based waste material

Step 1: Grind it up
Whatever you’re starting with, from computer parts to turkey giblets, will need to be chopped and churned into a fine, grainy mess.

Step 2: Add Water
According to a May 2003 Discover magazine article, this is the step that makes Changing World Technology’s version of thermal depolymerization unique. Other attempts to recreate the process tried to siphon water away from the waste. CWT figured out that if they add more, then they don’t have to heat or pressurize the sludgy glop nearly as much as they would for dry materials—the water helps spread the effect of the heat more efficiently.
Step 3: Depressurize
By quickly pumping the heated, pressurized slop into a depressurization chamber, CWT makes most of the water instantly evaporate out, a necessary step that would take a lot longer and a lot more energy to do by boiling. If you’re making oil from turkey, this is the point where powdery fertilizer, chock full of minerals from the bones, settles out.
Step 4: Keep it Hot, Hot, Hot
The remaining liquid is heated to about 900 degrees F and sent through a series of distillers that separate it into natural gas, two different qualities of oil, and powdered carbon. The gas is used to fuel the process and the rest goes up for sale. For about 200 tons of turkey bits, the whole shebang takes less than 24 hours.

Comments (9)
  1. I actually did hear about this a long time ago, and I still don’t understand why a plant has’t replaced every single waste processing facility in the nation. It is the only means of treating solid waste that destroys all organic life — even down to viruses like HIV.

    Now I know why it hasn’t spread like wildfire — Congress is full of idiots. (Well, we already knew that.) Hopefully if the information becomes more widespread the technology will too.

  2. wikipedia has this to say about the tax credit:

    “A biofuel tax credit of roughly $1 per US gallon (26 ¢/L) on production costs was not available because the oil produced did not meet the definition of “biodiesel” according to the relevant American tax legislation. The Energy Policy Act of 2005 specifically added thermal depolymerization to a $1 renewable diesel credit, which became effective at the end of 2005.”

    i’m hoping that’s true…

  3. if it sounds to good to be true, it usually is!
    from all the reading/studying that I have done on “making petroleum products” always claim that the cost would be much more than what we are paying today. maybe someone somewhere can tinker some more???

  4. I remember reading the orginal Discover article. I was intrigued by it. Kudos on bringing it up in Mental_Floss. I can’t wait until we start doing something with this technology.

  5. I first heard about thermal depolymerization more than 5 years ago. I have followed the company off and on since then.

    At the time, they had a small-scale working reactor that could process anything, just as advertised. The turkey plant was their first large-scale attempt. If that worked well, they had 100’s of customers waiting to buy a thermal depolymerization plant. (Eliminate the waste disposal bills and produce energy; who wouldn’t?)

    Well the first trial was to take a year. That was about 4 years ago. When I last contacted them they explained that there were still some kinks to work out. I take it to mean that the project did not scale up as well as had been anticipated.

    Over the years I have maintained hope for TD, but I grow more skeptical. Remember, the promise of Cold Fusion?

  6. Right now the oil from TDP costs about $80/barrel, whereas oil pulled from the earth runs

  7. Runs what?

  8. Laen meant to say that oil per barrel runs at about $60 today. At that price, gas is ~$2.80/gallon. TDP produces diesel oil, supposedly, that costs ~$80/barrel. Or about 30% more than current world oil prices.

    Do you think that majority of people, not to mention businesses, which will use the oil, would pay $3.5o/gal of more for gas? Voluntarily? The answer is no.

    Give TDP a credit of a $1/gal and it’s somewhat equal, but as consumers the credit comes out of another one of our pockets. Either the process has to stand on it’s own two legs and be cost worthy, or we have to wait until oil is more expensive. Just like with wind, solar, etc.

  9. to hell with the money we can clean the entire world with this process an stop polluting streams with sewer an stop and fills an dissassemble anthrax believe it or not an might even dissassemble radioactive waste too

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