DISCOVER Vol. 24 No. 5 (May 2003)
In an industrial park in Philadelphia sits a new machine that can change almost anything into oil.
"This is a solution to three of the biggest problems facing mankind," says Brian Appel, chairman and CEO of Changing World Technologies, the company that built this pilot plant and has just completed its first industrial-size installation in Missouri. "This process can deal with the world's waste. It can supplement our dwindling supplies of oil. And it can slow down global warming."
Pardon me, says a reporter, shivering in the frigid dawn, but that sounds too good to be true.
"Everybody says that," says Appel. He is a tall, affable entrepreneur who has assembled a team of scientists, former government leaders, and deep-pocketed investors to develop and sell what he calls the thermal depolymerization process, or TDP. The process is designed to handle almost any waste product imaginable, including turkey offal, tires, plastic bottles, harbor-dredged muck, old computers, municipal garbage, cornstalks, paper-pulp effluent, infectious medical waste, oil-refinery residues, even biological weapons such as anthrax spores. According to Appel, waste goes in one end and comes out the other as three products, all valuable and environmentally benign: high-quality oil, clean-burning gas, and purified minerals that can be used as fuels, fertilizers, or specialty chemicals for manufacturing.
Unlike other solid-to-liquid-fuel processes such as cornstarch into ethanol, this one will accept almost any carbon-based feedstock. If a 175-pound man fell into one end, he would come out the other end as 38 pounds of oil, 7 pounds of gas, and 7 pounds of minerals, as well as 123 pounds of sterilized water. While no one plans to put people into a thermal depolymerization machine, an intimate human creation could become a prime feedstock. "There is no reason why we can't turn sewage, including human excrement, into a glorious oil," says engineer Terry Adams, a project consultant. So the city of Philadelphia is in discussion with Changing World Technologies to begin doing exactly that.
"The potential is unbelievable," says Michael Roberts, a senior chemical engineer for the Gas Technology Institute, an energy research group. "You're not only cleaning up waste; you're talking about distributed generation of oil all over the world."
"This is not an incremental change. This is a big, new step," agrees Alf Andreassen, a venture capitalist with the Paladin Capital Group and a former Bell Laboratories director.
Andreassen and others anticipate that a large chunk of the world's agricultural, industrial, and municipal waste may someday go into thermal depolymerization machines scattered all over the globe. If the process works as well as its creators claim, not only would most toxic waste problems become history, so would imported oil. Just converting all the U.S. agricultural waste into oil and gas would yield the energy equivalent of 4 billion barrels of oil annually. In 2001 the United States imported 4.2 billion barrels of oil. Referring to U.S. dependence on oil from the volatile Middle East, R. James Woolsey, former CIA director and an adviser to Changing World Technologies, says, "This technology offers a beginning of a way away from this."
But first things first. Today, here at the plant at Philadelphia's Naval Business Center, the experimental feedstock is turkey processing-plant waste: feathers, bones, skin, blood, fat, guts. A forklift dumps 1,400 pounds of the nasty stuff into the machine's first stage, a 350-horsepower grinder that masticates it into gray brown slurry. From there it flows into a series of tanks and pipes, which hum and hiss as they heat, digest, and break down the mixture. Two hours later, a white-jacketed technician turns a spigot. Out pours a honey-colored fluid, steaming a bit in the cold warehouse as it fills a glass beaker.
It really is a lovely oil.
"The longest carbon chains are C-18 or so," says Appel, admiring the liquid. "That's a very light oil. It is essentially the same as a mix of half fuel oil, half gasoline."
Private investors, who have chipped in $40 million to develop the process, aren't the only ones who are impressed. The federal government has granted more than $12 million to push the work along. "We will be able to make oil for $8 to $12 a barrel," says Paul Baskis, the inventor of the process. "We are going to be able to switch to a carbohydrate economy."
Making oil and gas from hydrocarbon-based waste is a trick that Earth
mastered long ago. Most crude oil comes from one-celled plants and animals
that die, settle to ocean floors, decompose, and are mashed by sliding
tectonic plates, a process geologists call subduction. Under pressure and
heat, the dead creatures' long chains of hydrogen, oxygen, and
carbon-bearing molecules, known as polymers, decompose into short-chain
petroleum hydrocarbons. However, Earth takes its own sweet time doing
this—generally thousands or millions of years—because subterranean heat
and pressure changes are chaotic. Thermal depolymerization machines
turbocharge the process by precisely raising heat and pressure to levels
that break the feedstock's long molecular bonds.
The technicians here have spent three years feeding different kinds of waste into their machinery to formulate recipes. In a little trailer next to the plant, Appel picks up a handful of one-gallon plastic bags sent by a potential customer in Japan. The first is full of ground-up appliances, each piece no larger than a pea. "Put a computer and a refrigerator into a grinder, and that's what you get," he says, shaking the bag. "It's PVC, wood, fiberglass, metal, just a mess of different things. This process handles mixed waste beautifully." Next to the ground-up appliances is a plastic bucket of municipal sewage. Appel pops the lid and instantly regrets it. "Whew," he says. "That is nasty."
Experimentation revealed that different waste streams require different cooking and coking times and yield different finished products. "It's a two-step process, and you do more in step one or step two depending on what you are processing," Terry Adams says. "With the turkey guts, you do the lion's share in the first stage. With mixed plastics, most of the breakdown happens in the second stage." The oil-to-mineral ratios vary too. Plastic bottles, for example, yield copious amounts of oil, while tires yield more minerals and other solids. So far, says Adams, "nothing hazardous comes out from any feedstock we try."
"The only thing this process can't handle is nuclear waste," Appel says. "If it contains carbon, we can do it." à
This Philadelphia pilot plant can handle only seven tons of waste a day, but 1,054 miles to the west, in Carthage, Missouri, about 100 yards from one of ConAgra Foods' massive Butterball Turkey plants, sits the company's first commercial-scale thermal depolymerization plant. The $20 million facility, scheduled to go online any day, is expected to digest more than 200 tons of turkey-processing waste every 24 hours.
The north side of Carthage smells like Thanksgiving all the time. At
the Butterball plant, workers slaughter, pluck, parcook, and package
30,000 turkeys each workday, filling the air with the distinctive tang of
boiling bird. A factory tour reveals the grisly realities of large-scale
poultry processing. Inside, an endless chain of hanging carcasses clanks
past knife-wielding laborers who slash away. Outside, a tanker truck
idles, full to the top with fresh turkey blood. For many years, ConAgra
Foods has trucked the plant's waste—feathers, organs, and other nonusable
parts—to a rendering facility where it was ground and dried to make animal
feed, fertilizer, and other chemical products. But bovine spongiform
encephalopathy, also known as mad cow disease, can spread among cattle
from recycled feed, and although no similar disease has been found in
poultry, regulators are becoming skittish about feeding animals to
animals. In Europe the practice is illegal for all livestock. Since 1997,
the United States has prohibited the feeding of most recycled animal waste
to cattle. Ultimately, the specter of European-style mad-cow regulations
may kick-start the acceptance of thermal depolymerization. "In Europe,
there are mountains of bones piling up," says Alf Andreassen. "When
recycling waste into feed stops in this country, it will change
Chemistry, not alchemy, turns (A) turkey offal—guts, skin, bones, fat, blood, and feathers—into a variety of useful products. After the first-stage heat-and-pressure reaction, fats, proteins, and carbohydrates break down into (B) carboxylic oil, which is composed of fatty acids, carbohydrates, and amino acids. The second-stage reaction strips off the fatty acids' carboxyl group (a carbon atom, two oxygen atoms, and a hydrogen atom) and breaks the remaining hydrocarbon chains into smaller fragments, yielding (C) a light oil. This oil can be used as is, or further distilled (using a larger version of the bench-top distiller in the background) into lighter fuels such as (D) naphtha, (E) gasoline, and (F) kerosene. The process also yields (G) fertilizer-grade minerals derived mostly from bones and (H) industrially useful carbon black.
Garbage In, Oil Out
Feedstock is funneled into a grinder and mixed with water to create a
slurry that is pumped into the first-stage reactor, where heat and
pressure partially break apart long molecular chains. The resulting
organic soup flows into a flash vessel where pressure drops dramatically,
liberating some of the water, which returns back upstream to preheat the
flow into the first-stage reactor. In the second-stage reactor, the
remaining organic material is subjected to more intense heat, continuing
the breakup of molecular chains. The resulting hot vapor then goes into
vertical distillation tanks, which separate it into gases, light oils,
heavy oils, water, and solid carbon. The gases are burned on-site to make
heat to power the process, and the water, which is pathogen free, goes to
a municipal waste plant. The oils and carbon are deposited in storage
tanks, ready for sale.
A Boon to Oil and Coal Companies
One might expect fossil-fuel companies to fight thermal
depolymerization. If the process can make oil out of waste, why would
anyone bother to get it out of the ground? But switching to an energy
economy based entirely on reformed waste will be a long process, requiring
the construction of thousands of thermal depolymerization plants. In the
meantime, thermal depolymerization can make the petroleum industry itself
cleaner and more profitable, says John Riordan, president and CEO of the
Gas Technology Institute, an industry research organization. Experiments
at the Philadelphia thermal depolymerization plant have converted heavy
crude oil, shale, and tar sands into light oils, gases, and graphite-type
carbon. "When you refine petroleum, you end up with a heavy solid-waste
product that's a big problem," Riordan says. "This technology will convert
these waste materials into natural gas, oil, and carbon. It will fit right
into the existing infrastructure."
Can Thermal Depolymerization Slow Global Warming?
If the thermal depolymerization process WORKS AS Claimed, it will clean
up waste and generate new sources of energy. But its backers contend it
could also stem global warming, which sounds iffy. After all, burning oil
creates global warming, doesn't it?
RELATED WEB SITES:
To learn more about the thermal depolymerization process, visit Changing World Technologies' Web site: http://www.changingworldtech.com/.
A primer on the natural carbon cycle can be found at www.whrc.org/science/carbon/carbon.htm.
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