Part II
Brian Appel, CEO of Changing World Technologies, strolls through a thermal depolymerization plant in Philadelphia. Experiments at the pilot facility revealed that the process is scalable—plants can sprawl over acres and handle 4,000 tons of waste a day or be "small enough to go on the back of a flatbed truck" and handle just one ton daily, says Appel.
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 everything."
Because depolymerization takes apart materials at the molecular level, Appel says, it is "the perfect process for destroying pathogens." On a wet afternoon in Carthage, he smiles at the new plant—an artless assemblage of gray and dun-colored buildings—as if it were his favorite child. "This plant will make 10 tons of gas per day, which will go back into the system to make heat to power the system," he says. "It will make 21,000 gallons of water, which will be clean enough to discharge into a municipal sewage system. Pathological vectors will be completely gone. It will make 11 tons of minerals and 600 barrels of oil, high-quality stuff, the same specs as a number two heating oil." He shakes his head almost as if he can't believe it. "It's amazing. The Environmental Protection Agency doesn't even consider us waste handlers. We are actually manufacturers—that's what our permit says. This process changes the whole industrial equation. Waste goes from a cost to a profit."
He watches as burly men in coveralls weld and grind the complex loops of piping. A group of 15 investors and corporate advisers, including Howard Buffett, son of billionaire investor Warren Buffett, stroll among the sparks and hissing torches, listening to a tour led by plant manager Don Sanders. A veteran of the refinery business, Sanders emphasizes that once the pressurized water is flashed off, "the process is similar to oil refining. The equipment, the procedures, the safety factors, the maintenance—it's all proven technology."
And it will be profitable, promises Appel. "We've done so much testing in Philadelphia, we already know the costs," he says. "This is our first-out plant, and we estimate we'll make oil at $15 a barrel. In three to five years, we'll drop that to $10, the same as a medium-size oil exploration and production company. And it will get cheaper from there."
"We've got a lot of confidence in this," Buffett says. "I represent ConAgra's investment. We wouldn't be doing this if we didn't anticipate success." Buffett isn't alone. Appel has lined up federal grant money to help build demonstration plants to process chicken offal and manure in Alabama and crop residuals and grease in Nevada. Also in the works are plants to process turkey waste and manure in Colorado and pork and cheese waste in Italy. He says the first generation of depolymerization centers will be up and running in 2005. By then it should be clear whether the technology is as miraculous as its backers claim.
EUREKA: 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.
— Brad Lemley
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."
Appel says a modified version of thermal depolymerization could be used to inject steam into underground tar-sand deposits and then refine them into light oils at the surface, making this abundant, difficult-to-access resource far more available. But the coal industry may become thermal depolymerization's biggest fossil-fuel beneficiary. "We can clean up coal dramatically," says Appel. So far, experiments show the process can extract sulfur, mercury, naphtha, and olefins—all salable commodities—from coal, making it burn hotter and cleaner. Pretreating with thermal depolymerization also makes coal more friable, so less energy is needed to crush it before combustion in electricity-generating plants.
— B.L. 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?
Carbon is the major chemical constituent of most organic matter—plants take it in; animals eat plants, die, and decompose; and plants take it back in, ad infinitum. Since the industrial revolution, human beings burning fossil fuels have boosted concentrations of atmospheric carbon more than 30 percent, disrupting the ancient cycle. According to global-warming theory, as carbon in the form of carbon dioxide accumulates in the atmosphere, it traps solar radiation, which warms the atmosphere—and, some say, disrupts the planet's ecosystems.
But if there were a global shift to thermal depolymerization technologies, belowground carbon would remain there. The accoutrements of the civilized world—domestic animals and plants, buildings, artificial objects of all kinds—would then be regarded as temporary carbon sinks. At the end of their useful lives, they would be converted in thermal depolymerization machines into short-chain fuels, fertilizers, and industrial raw materials, ready for plants or people to convert them back into long chains again. So the only carbon used would be that which already existed above the surface; it could no longer dangerously accumulate in the atmosphere. "Suddenly, the whole built world just becomes a temporary carbon sink," says Paul Baskis, inventor of the thermal depolymerization process. "We would be honoring the balance of nature."
— B.L. |
