New Technology Turns Waste into Valuable Components
by Kelly Hart
There is a technological revolution quietly brewing new hope for sustainably dealing with the massive waste stream produced by the activities of mankind. Not only does the thermal depolymerization process (TDP) deal with any carbon-based waste effectively, but it creates valuable products as a net result: high-quality oil, clean-burning gas, and purified minerals. In other words, if you put waste material such as chicken guts, old tires, obsolete computers, municipal garbage, sewage, infectious medical waste or even biological weapons into one end of the machine (which looks somewhat like a small oil refinery,) what you end up with is purified water, oil similar to heating fuel, gas that can also be used as fuel, and various useful minerals.
If this sounds too good to be true, then consider this: the Butterball Turkey processing plant in Carthage , Missouri is using a TDP apparatus to reprocess some 200 tons of turkey offal produced each day into about 600 barrels of light oil, which can be used to heat homes. If all of the agricultural waste produced in the U.S. were converted this way, about 4 billion barrels of fossil fuel each year would not have to be pumped out of the ground. This could go a long way toward energy independence and even thwarting the motivation for international warfare, while keeping the existing fossil fuel based infrastructure. This could give us time to get our act together to develop large-scale renewable energy technologies that don't produce so much of the carbon dioxide that contributes to global warming.
The inventor of TDP is Paul Baskis, a microbiologist from Illinois . He sold his patents to Changing World Technologies in 1997, and they are the company now promoting the concept. Paul's brilliant idea was to heat and pressurize organic waste with lots of water as a solvent, rather than trying to dry out or remove the water from the material. Then the slurry is suddenly depressurized, which removes about 90% of the free water. Next, the soup is heated further to help break the polymers (large organic molecules) into smaller ones. After this, the material is sent through a process similar to an oil refinery, where it is distilled into the component gasses, light and heavy oils, water and solid carbon. The water is returned to the front of the process to make a slurry of the next batch, while the gas produced is used to heat it up. In this way the TDP is about 85% efficient.it only takes about 15% of the energy produced to keep the process running!
The temperatures and pressures need only be low as industrial processes go, since the water helps to convey heat into the material. Temperatures of 500 to 900 degrees Fahrenheit and pressures of about 600 psi for most organic material is all that is necessary, and the cooking times are pretty short, usually about 15 minutes. The overall process takes about two hours for most materials.
"We will be able to make oil for $8 to $12 a barrel," says Paul Baskis. "We are going to be able to switch to a carbohydrate economy. Suddenly, the whole built world just becomes a temporary carbon sink. We would be honoring the balance of nature." TDP mirrors the natural process that takes millions of years beneath the surface of the earth to convert organic material into oil; it just speeds the process up.
In addition to private investors, who have contributed $40 million to develop the process, the federal government has granted more than $12 million, partly through the Environmental Protection Agency. They are interested in finding ways to safely deal with toxic substances, such as contaminated animal products, without having to burn them. Because depolymerization takes apart materials at the molecular level, it is the perfect process for destroying pathogens. Nothing hazardous has come out from any materials they have tried. If something contains carbon, the process works, although the process can't handle nuclear waste.
Changing World Technologies is planning to build demonstration plants to process chicken parts and manure in Alabama, crop residuals and grease in Nevada, turkey waste and manure in Colorado, and pork and cheese waste in Italy.
Different materials yield different ratios of output materials. For instance, 100 pounds of plastic bottles might yield 70 pounds of oil, 16 pounds of gas, 6 pounds of carbon solids, and 8 pounds of water; where 100 pounds of old tires might yield 44 pounds of oil, 10 pounds of gas, 44 pounds of carbon and metal solids, and 4 pounds of water. If a 100 pound human happened to fall into the hopper, the yield would be about 22 pounds of oil, 4 pounds of solid minerals, 4 pounds of natural gas, and 70 pounds of water.
The processing of each material can be tweaked in ways that result in more specialized chemicals, such as fatty acids and hydrochloric acid. PVC waste can be processed safely this way, because the hydrogen in water combines with the chlorine in PVC to make it safe. The mixed waste that results from grinding up old computers or refrigerators can be handled with no problem.
The TDP could make the petroleum industry itself cleaner and more profitable. When you refine petroleum, you end up with a heavy solid-waste product that is a big problem, but this technology can convert these waste materials into natural gas, oil, and carbon. The coal industry may become the biggest fossil-fuel beneficiary from the use of TDP; experiments show that the TDP can pre-treat coal and extract sulfur, mercury, naphtha, and olefins, making the coal burn hotter and cleaner.
Since the industrial revolution, human beings burning fossil fuels have boosted concentrations of atmospheric carbon more than 30 percent. 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. But if there were a global shift to TDP technologies, belowground carbon would remain there. On the surface, the accoutrements of the civilized world would then become temporary carbon sinks. At the end of their useful lives, they would be converted in TDP 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. This may slow down the accumulation carbon dioxide in the atmosphere, especially if we focus on ways of creating and utilizing energy that doesn't rely on burning fuels, which is very exciting prospect!
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