|Plasma gasification burns waste to create energy
Neither plasma torches nor gasification technology is new, but Alter NRG Corp. of Canada is banking on the combination of the two as a better method for disposing of municipal waste and creating clean power.
In the past, plasma gasification (PG) technology had been used primarily to dispose of extremely hazardous waste materials. In the last few years, as landfills have filled up and energy prices have risen, there has been more support for PG as a way to process normal household waste.
Westinghouse Plasma Corporation (WPC) has been working on plasma torch technology for over 50 years, and has used PG technology at two plants in Japan, run by Hitachi. In April of 2007, Alter NRG, a Canadian company, bought WPC.
For fuel, the WPC plants in Japan will take “anything that comes out of your house,” said Mark Montemurro, chairman of Alter NRG. One of the plants shreds everything before it is gasified, while the other plant simply removes the large pieces, like appliances or large pieces of construction debris. One of the plants also uses up to 30 percent shredder fluff along with municipal waste.
Montemurro said that in Japan, up to 70 percent of the waste stream is used to create energy through gasification and incineration, while Europe uses about 30 percent. The United States and Canada lag far behind.
Montemurro said that Canada, with its bounty of open land, hasn’t worried much about using space for landfills. However, Ontario currently ships about 30 percent of its municipal waste into Michigan, and that door my soon be closed, drawing attention to the need for alternatives for disposing of the waste.
The PG technology licensed by Alter NRG creates “syngas” which can be burned to create electricity. It is also possible to produce diesel, gasoline or other fuels, but Montemurro said that for now, Alter NRG is focusing on syngas.
He also said that while it’s possible to use the plasma gasification technology to convert coal to liquid fuel, the processes are different enough that he doesn’t anticipate building any facilities that accept both coal and waste – at least not right away.
Plasma gasification works by using intense heat, over 12,000 degrees, to turn the solid material into gas, principally hydrogen, carbon dioxide and carbon monoxide, which is converted into syngas.
During the process, metals are melted and removed, and glass-like slag is left which can be used like aggregate in paving materials. Montemurro said that one group is looking at the possibility of blowing air through the molten slag to create a Fiberglas-like substance that could be used as insulation.
While the slag may contain some trace amounts of metals or other substances that could be classified as hazardous if they were separate, Montemurro likened it to leaded crystal glassware, where the lead is encapsulated by the glass so it is not harmful.
One possible market for plasma gasification technology is retrofitting coal-fired power plants, Montemurro said, by “sticking that gasifier in front of it,” to create electricity without the emissions that burning coal creates. Emissions data from the Hitachi plants in Japan is “well below any of the emissions thresholds” that would be required in the United States or Canada.
While some water is used in the process, it is all recycled through the plant, so there is no water discharge. The slag has gone through thorough testing, and even the odors from the waste are contained inside the facility. “It’s not like some refinery sitting in your back yard,” Montemurro said.
Montemurro said that other companies have looked into similar technologies. “There seems to be a handful of people – but they don’t have the R&D or people or funds,” he said. “These are not small projects. It requires capital.” So far, Westinghouse has spent $20 million on the technology.
WPC has a plasma gasification pilot plant Pennsylvania, where more than 100 tests have been completed on a wide range of feedstocks, and the two plants operating in Japan to prove that the technology works on a commercial basis.
The WPC technology has been licensed to two plants in India, which are expected to be running later this year. In the United States, Alter NRG has a licensing agreement with NRG Energy, a United States power producer, who will use the WPC technology on coal and other feedstocks to produce electricity.
Alter NRG has also licensed the technology to Geoplasma, which is building a facility in St. Lucie County, Florida, to convert waste into electricity. That plant is expected to be operational in 2009 or 2010. “We’ve got a number of opportunities identified,” Montemurro said of future prospects.
He said that while some people look at PG technology as a replacement for recycling, he said that he feels it “will dovetail nicely with recycling/re-use projects,” as people become more aware of what happens to waste materials.
Montemurro also said that PG offers many different opportunities for other companies. Alter NRG is “more focused on making electricity,” while other companies may want to convert coal to liquid fuel or focus on feedstocks other than municipal waste. He said, “There’s a place for all to be successful.”