March 7, 2007

Plasma...that's the ticket

It's becoming increasingly clear that we cannot continue to produce a prodigious amount of waste and simply bury it all in landfills. We are running out of room, and the economic and environmental costs of continuing our landfilling scheme are growing exponentially.

Four years ago, Discover magazine published an article that seemed to offer an amazingly viable option to deal with the millions of pounds of trash we produce everyday. The first small-scale thermal depolymerization plant was just then coming online, using a technology that ground up, heated, pressurized, heated, and eventually distilled any sort of waste into reusable materials. A quote from the article that has stuck with me reports that
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.
The initial entries into the small-scale plant were to be 200 tons of turkey offal from a Butterball plant in Missouri.

The process was reported to be 85% efficient, meaning that of 100 BTU of energy in the waste put into the process, 85% could be recovered and reused - an absolute miracle level of recapture for any waste process.

A year later, Discover published an update on the process suggesting that things would be running along in just a short while. A 2006 update, then suggested that there were a few more hurdles to be overcome - most of them legislative as the process was competing for scarce funding dollars with other alternative energy source lobbies in Washington, DC. The technology isn't dead, but it has been much slower to come to fruition than initial excitement suggested.

This past month, then, Popular Science published an article about another alternative for trash disposal involving a plasma decomposition process. The trash is initiall chopped up in huge grinders and then placed into a vessel that has a 650-volt current passing between electrodes, heating the air in the vessel to high enough temperatures that the trash is broken down into very small molecules and pure elements. Two products come out of the reactor vessel - syngas ("a mizture of primarily hydrogen and carbon monoxide that can be converted into a variety of marketable fuels, including ethanol, natural gas, and hydrogen") and "an obsidian-like glass used as a raw material for numerous applications including bathroom tiles and high-strength asphalt."

The amazing part of the whole deal, however, is that the syngas comes out at 2200 degrees fahrenheit and generates steam as it cools, turning turbines that produce electricity - two-thirds of which goes into continuing the process and one-third of which ends up as energy profit, able to be sold back to electrical utilities or to heat and power the rest of the plant.

Trash goes in and energy comes out.

It could be a miracle technology, folks.

If you have a few bucks to invest, do me a favor and throw some the way of an alternative energy scheme, would ya? And if it happens to be one of these two, I certainly wouldn't be too bothered.

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