Plasma Gasification

Wednesday, July 9th, 2014

There is value in trash — if you can unlock it:

That’s what this facility in northern Oregon is designed to do. Run by a startup called S4 Energy Solutions, it’s the first commercial plant in the US to use plasma gasification to convert municipal household garbage into gas products like hydrogen and carbon monoxide, which can in turn be burned as fuel or sold to industry for other applications. (Hydrogen, for example, is used to make ammonia and fertilizers.)

Here’s how it works: The household waste delivered into this hangar will get shredded, then travel via conveyer to the top of a large tank. From there it falls into a furnace that’s heated to 1,500 degrees Fahrenheit and mixes with oxygen and steam. The resulting chemical reaction vaporizes 75 to 85 percent of the waste, transforming it into a blend of gases known as syngas (so called because they can be used to create synthetic natural gas). The syngas is piped out of the system and segregated. The remaining substances, still chemically intact, descend into a second vessel that’s roughly the size of a Volkswagen Beetle.

This cauldron makes the one above sound lukewarm by comparison. Inside, two electrodes aimed toward the middle of the vessel create an electric arc that, at 18,000 degrees, is almost as hot as lightning. This intense, sustained energy becomes so hot that it transforms materials into their constituent atomic elements. The reactions take place at more than 2,700 degrees, which means this isn’t incineration—this is emission-free molecular deconstruction. (The small amount of waste material that survives falls to the bottom of the chamber, where it’s trapped in molten glass that later hardens into inert blocks.)

The seemingly sci-fi transformation occurs because the trash is blasted apart by plasma—the forgotten-stepsister state of matter. Plasma is like gas in that you can’t grip or pour it. But because extreme heat ionizes some atoms (adding or subtracting electrons), causing conductivity, it behaves in ways that are distinct from gas.


  1. Bob Sykes says:

    We’ve been down this fantasy road many times. Me personally included. There are several problems here, all related to cost per Btu obtained and process reliability.

    First, trash is a very low value fuel, being mostly paper. So large amounts of it have to be processed to get anything useful. Then, it starts out dispersed through the community, and its collection is very expensive. Moreover, the plasma reactor is a very highly capital intensive device. Finally the fuel itself is highly variable both in quantity and composition, and this makes control of the process an engineering nightmare.

    So, the overall costs are prohibitive, and the process is guaranteed to fail.

    Back in the 1970′s, people tried to get energy out of so-called “free” trash by burning it. This is a much simpler and much lower cost technology than the one described above. And several plants were actually built.

    The result was electric power costs literally ten times what the regional power companies asked, and the process was much less reliable power.

    One of the risks of trash is that variability mentioned above. Municipal trash often contains explosive material like cans of waste gasoline or paint. You will even get the occasional bag of gun powder or ammunition or even dynamite or ammonium nitrate. As a result, you get about one explosion every 300,000 tons or so. The explosions occur during the shredding process.

    When Columbus, OH, was burning trash (very expensively and very unreliably) at least one of their four shredding stations was done every day because of explosions. It takes months to get one back up and running. The shredders were there to reduce transportation costs, so the lack of at least one shredder drove up costs significantly.

    Columbus finally shut down its whole trash-to-electricity system and ate the bonds that it was supposed to pay for. If I remember correctly, they lost about $200,000,000. Nowadays, Columbus’ trash goes into a landfill, unshredded and unsorted. Excess recyclables from the City’s recycling program often join it.

    The landfill does produce modest amounts of methane, some of which is used for space heating in the nearby jail.

    The engineering problem is sweet, but the pseudo-solution won’t fly. It’s just another example of environmental/socialist delusion.

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