Plasma Gasified Waste


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700-acre Columbia Ridge Landfill in Arlington, Oregon processes 35,000 tons of household trash weekly by train from Seattle and by truck from Portland.  It is owned by Waste Management.

As of November 2014, not all the trash arriving at Columbia Ridge got buried.  Some of it was destined for a special kind of treatment—one that could redefine how we think about trash.

“Our goal is to extract as much value as possible from waste and this project will help us recover resources to generate clean fuels, renewable energy and other beneficial products,” said Dean Kattler, area vice president for Waste Management Pacific Northwest.

There is value in trash if you can unlock it.  S4 Energy Solutions and Waste Management combined and built the first commercial plant in the US that uses plasma gasification to convert municipal household garbage into gas products.

The seemingly sci-fi transformation occurs because the trash is blasted apart by plasma.  Plasma is a cloud of protons, neutrons and electrons where all the electrons have come loose from their respective molecules and atoms, giving the plasma the ability to act as a whole rather than as a bunch of atoms.  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 differently from gas.

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Plasma

Until now, plasma gasification has proven too energy and capital intensive for real world use on everyday trash.  The value of the syngas produced was worth less than the amount of energy required to power the furnaces and melt the trash.

The US generates about 250 million tons of trash a year. Even with recycling and composting facilities tackling an estimated 85 million tons of refuse per year, it would take thousands of expensive new plants to handle the nation’s municipal trash output.

Jeff Surma, cofounder of S4 Energy Solutions may have finally solved that problem. (S4 refers to plasma, the fourth state of matter. The other three are solid, liquid, and gas.)

In 1985, freshly graduated from Montana State University, he was hired by Pacific Northwest National Laboratory to work on nuclear waste. Beginning with the Manhattan Project, the US government cooked most of the plutonium for America’s nuclear weapons arsenal with its nine nuclear reactors, giant plutonium processing plants, and buried tanks of radioactive sludge, earning the site the distinction of being one of the most contaminated nuclear waste sites in the Western Hemisphere.

Surma’s first project was to work on joule-heated melters, a method for processing nuclear waste. This chemical process, known as vitrification, immobilizes radioactive materials in an inert form of glass. The team was able to convert all the nuclear waste into four-foot-tall canisters of vitrified glass.

But the facility also had huge quantities of  low-level radioactive trash that couldn’t go to a landfill and wasn’t suited for vitrification.

So, Surma learned about the plasma torch that scientists at NASA were using to mimic the effect of extreme heat on manned spacecraft reentering the atmosphere and that plasma for processing waste was being used in the metal and chemical industries to dispose of their very expensive toxic sludge.

Simultaneously, GE high-voltage engineer, Charles Titus, became convinced that the current technology using metal torches didn’t work because they got damaged by the very heat they delivered.  So, he created plasma with an electric arc strung between two graphite electrodes.

Also around that time, MIT physicist, Dan Cohn, at Plasma Science and Fusion Center was searching for plasma technology’s possible environmental applications.

Cohn, Titus and Surma connected and before long they were brainstorming on how to get the technology to dispose of the billions of tons of common household trash (MSW).

The challenge was the high energy costs, the heterogeneity of municipal solid waste, and the toxins in heavy metals (busted televisions, microwave ovens, dead batteries, broken thermometers, old paints) that aren’t broken down by plasma and need to be safely kept away from all water supplies.

The trio also knew that the massive municipal solid waste market would need a clean system with no harmful byproducts or their project could look like another form of incineration, that has a bad reputation due to the air pollution it creates.

Surma thought they could combine plasma with vitrification to handle the harmful byproducts, but they needed to keep the resulting molten inert glass byproducts at the bottom of the vessel from cooling down and hardening.

Since, this molten glass needs alternating current to maintain steady temperature and the electric arc for the plasma runs on direct current, Titus designed a system that would enable DC and AC to cohabitate within a plasma gasification furnace with a melter.  The team calculated that this approach would provide just enough energy to sustain the plasma, atomize the trash, and keep the glass in a molten state.

Within a few months Jeff Surma, Dan Cohn, and Charles Titus  launched their company, Integrated Environmental Technologies (InEnTec).

Their first commercial units were sold to Boeing and Kawasaki, which produce lots of hazardous waste at a great disposal cost.

“It was always our intent, from the very first patent, to go after the municipal solid waste stream,” Surma said. “But customer pull drew us into more lucrative hazardous- and medical-waste treatment.”

With InEnTec’s chief engineer, Jim Batdorf, they tried to come up with ways to make their technology economically feasible  for the more challenging miscellaneous content of household garbage.

The breakthrough was to stack a conventional gasifier above the plasma-enhanced melter.  The trash gets heated and treated by this preliminary gasifier, then moves into the chamber with the plasma zapper and vitrification.  This strategy improves efficiency because it takes less energy for the plasma to blast materials that are already heated.

The machine is illustrated below by Jim Batdorf.

1: Gasification.  A conveyer belt delivers shredded trash into a chamber mixed with oxygen and steam heated to 1,500 degrees Fahrenheit transforming about 80 percent of the waste into a mixture of gases that are piped out of the system.

2: Plasma Blasting.  Material that doesn’t succumb to the initial heat enters a specially insulated cauldron.  An 18,000-degree Fahrenheit electric arc runs between two electrodes creating a plasma zone in the center of the container.  Exposed to this intense heat, almost all the remaining trash gets blasted into  atomic elements and the resulting gases are piped out.

3: Hazmat Capture.  At the bottom of the cauldron sits a joule-heated melter that maintains a molten glass bath to trap any hazardous material left over from the plasma process.

4: Recycling.  The inert molten glass is drawn out of the system to be converted into low-value materials such as road aggregate.  The liquified metals are recycled into steel.

5: Fuel Capture. The sequestered syngas (mostly carbon monoxide and hydrogen) is cleaned, sold and converted to fuels like diesel and ethanol, used to produce electricity on sight and off, or used as a substitute for natural gas in heating and electricity generation.

 After a review that lasted more than two years, Waste Management determined that InEnTec was one of the few firms in the world whose plasma gasification technology looked viable.  Waste Management started as an equity interest in S4Energy Solutions LLC, a joint venture with InEnTec Inc., and later became an equity partner in InEnTec. The two companies are developing a plasma gasification plant in Arlington, Oregon, using InEnTec’s plasma enhanced melter (PEM) technology and Waste Management’s Columbia Ridge Landfill.

Carl Rush, a senior vice president at Waste Management says, “The easy answer used to be: Store it in a can, put it in a truck, and then send it to a big hole in the ground.  We’re moving away from that as a society.”

People don’t like landfills, it’s becoming costlier to transport and bury garbage, and even in the spacious American West, landfills are gradually butting up against more backyards and inching their way toward local water tables.

Waste Management, the largest owner of landfills, hopes they will help accelerate the transition to an era in which the very idea of garbage itself is garbage.  And they want to be positioned to profit when that time comes.  Time to invest?

Trash-to-fuel technology has been around since the 1970s.  Burning waste to generate electricity produces a stew of byproducts that need to be disposed of no matter how fancy the emissions scrubbers are.  So, environmentalists and some in the industry have remained skeptical of trash-to-fuel because it doesn’t address concerns for our overconsumption, it diverts resources and focus from recycling programs, and MSW plasma gasification technology is still too new to make any difference.

Construction of the Columbia Ridge plant was recently completed, and the Oregon Department of Environmental Quality has issued all the permits necessary for the facility to begin operations.  The plant is still so new that it remains to be seen whether the quality and quantity of the syngas can produce fuel good enough to use.  The operation will begin as a small 25 ton per day commercial demonstration plant. That’s 34,825 tons short of the MSW the landfill currently takes in.

So!  Will we get a guilt-free-energy-producing solution to our waste problems?  Some things to consider:

  • http://www.mdpub.com/gasifier/     for a DIY home gasifier!  This guy is a true engineer mind.
  • Communities that have installed waste conversion facilities tend to have a more positive opinion of the technologies, according to the EPA.
  • Real-world cost and environmental information is difficult to obtain primarily due to the current stage of U.S. development of conversion technologies.   http://www.wte.org/userfiles/files/ERC_2014_Directory.pdf
  • EPA estimates that gasification of MSW saves 6.5—13 MMBtu per ton as compared to landfill disposal.
  • Additional research that could be done in the near term to advance the understanding of conversion technologies might include:  High vs low feedstock BTU value,  Plant energy conversion efficiency,  Recovery of MSW for recycling,  Beneficial uses for different end gases,  Distance to market for syngas,  Market prices for energy products, Market prices for recyclables and other byproducts.

How You Can Help:

Use less—No matter how efficient we make our processes, and no matter how well we deal with waste, we cannot reach carbon neutrality without reducing our resource consumption.

Until next week:images-3

Garbage Girl

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2 thoughts on “Plasma Gasified Waste

  1. I Always enjoy your articles Audrey! Keep up the good work of informing us so we can transform our own communities! Robert Arias Bernalillo, New Mexico

    Like

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