One way municipalities around the US are jumping on the clean technology/renewable energy train is by building landfill gas-to-electricity systems. Making use of the methane emitted from decaying trash in landfills to generate power and heat looks like a win-win situation: rather than emitting the off-gas into the atmosphere it’s used to produce a clean form of energy.
A number of start-up ventures are looking to take the idea further. Rather than dumping trash in landfills and capturing the methane that’s produced, they’re looking to process and recycle streams and batches of whatever kind of waste and turn it directly into clean forms of energy and other useful products.
The CEO of one such company, Jeffrey E. Surma of InEnTec, got on the Web in an hour-long chat yesterday hosted by the Greenopolis clean tech social network to discuss their technology and its prospects.
Processing mixed streams and batches of all the waste we produce is a thorny problem both technically and financially, one that researchers such as those now working at InEnTec have been trying to solve for decades now.
The proprietary technology and process InEnTec’s (for Integrated Environmental Technologies) come up with is to feed waste streams or batches into what’s called a ‘Plasma Enhanced Melter’.
The ‘plasma’ is an electrically charged, conducting gas inside a high-pressure container. Passing the waste through the PEM turns just about any type of waste we produce – plastics, gas, organic waste, metals, even medical, radioactive, industrial and municipal waste – into a hydrogen-rich ‘syngas’ that can be used to power a turbine generator. A vitrified, ‘glassy’ solid waste is also produced, one that can be used in the manufacture of industrial and building products, such as roofing tiles and insulating panels.
The syngas produced is 40-45% hydrogen and 35-40% carbon monoxide with a heating value that typically ranges between 250-290 Btu/scf. It can be used directly or mixed into streams made up of natural gas, propane or diesel fuel to increase power generation.
Alternatively, hydrogen can be extracted from the syngas and this can be used in fuel cells and in oil refineries, as well as other chemical and industrial plants that can make use of high-purity hydrogen gas streams.
Efficiency and Emissions
In terms of energy efficiency, larger PEM systems can produce more power than they consume, though this depends on the make-up of the waste stream.
Environmentally, the nearly total destruction and reformation of the organic waste fed into the system produces very little in the way of emissions of greenhouse gas or hazardous pollutants, a factor that’s especially important now that the EPA’s going to be more strictly enforcing emissions standards, the company says.
“There can be CO2 emissions from gasification processes; however the emissions can be dramatically reduced as opposed to other disposal options. This is especially true if the waste is converted into a fuel and it is used as a substitute to a fossil fuel,” Surma said in response to a question during yesterday’s live Web chat.
Gasification of the waste by plasma heating and subsequent scrubbing and filtration as opposed to combustion or physical decay results in greenhouse gas and hazardous substance emissions from InEnTec’s PEM systems being “considerably lower” than those produced from incineration or landfill dumping, according to the company. Emissions of mercury, dioxins and furans, for example, are virtually eliminated, while metal emissions are greatly reduced as compared to those produced from incineration.
Interested? Here’s a link to yesterday’s Web chat.
You can also check out this video to learn more.