Image credit: InventorSpot, Christopher Nagy
The saying "one man's trash is another man's treasure" is ringing true in the world of waste management. When most Americans think of alternative energy, a few words probably come to mind: "wind," "solar" or even "hydrogen." Few would consider their trash a viable source of power — but they would be mistaken.
In recent years, a resurgence of interest in waste-based energy has prompted the expansion of landfill-gas-to-energy and waste-to-energy facilities and projects across the nation. A new and emerging waste based technology that is attracting some interest is gasification.
There are a number of forms of gasification technology being actively marketed for processing waste including plasma arc gasification; plasma torch gasification; pyrolysis; and combined pyrolysis-gasification systems. For most people it looks like another "black box" or "silver bullet" solution to addressing our waste management challenges. While there are a lot of hurdles to its development, it does hold the potential to process a wide range of waste streams to generate clean renewable fuels and electricity. In particular, one gasification technology that has emerged as a potential game changer is the Plasma Enhanced Melter (PEM) technology. With the development of the PEM technology, gasification technology has progressed to the point of being considered a source of green energy. Because of its ability to process heterogeneous waste streams, some enthusiasts go so far as to call plasma-assisted gasification 'the ultimate form of recycling.' The PEM technology is changing the game, because it could effectively harvest the energy potential that's hidden in the waste stream.
The PEM technology takes some of the best points of previous waste to energy methods and combines them with the power of a super-heated plasma arc. This process makes it possible to expand the kinds of waste streams that can be converted into energy and other useful materials.
How the PEM process works.
In a nutshell, the process works like this: waste is loaded into the PEM, where it first goes through a process of partial oxidation. This process gasifies a portion of the waste, which is siphoned to make syngas. The remaining solids are then lowered into a molten glass bath, heated by — you guessed it — an intense plasma arc. As the garbage reaches temperatures between 10,000 and 20,000 degrees Fahrenheit the heat breaks down the chemical bonds, releasing the atoms and molecules to be reused in the form of syngas, or other materials. A video describing the process can be seen at www.S4EnergySolutions.com
Metal waste is captured - not emitted.
Perhaps the most impressive part of the process is what happens next. The PEM system not only captures the resulting gases to produce a super-clean syngas, it also collects the other inorganic compounds as well. Metals are drained through the bottom of the melter and are combined to make a recyclable alloy, while the rest are combined and formed into a glass-like substance that can be reused as building materials.
The final stage in the process has to do with refining the hydrogen-rich syngas released throughout the PEM's process. As you might expect, the hot burning plasma arc produces a very clean product. Still, it must undergo a multi-stage scrubbing process in order to reach a rating of ultra-pure. Once it reaches the ultra pure state, syngas can be converted into liquid fuels like ethanol or hydrogen, or it can be burned for electricity generation similar to natural gas.
Waste Management and InEnTec have formed a joint venture to develop, operate and market plasma gasification facilities using the PEM technology. The joint venture is expected to process waste from the country's increasingly segmented commercial and industrial waste streams and hopefully expand the portfolio of renewable energy sources. This joint venture creates an opportunity to better manage our waste in a resourceful way.
As the nation and our world moves toward a more sustainable lifestyle, it's important to keep in mind that even the tons of trash we throw away each day can be turned into valuable, renewable energy. Perhaps it's now time to add "waste" to our alternative energy vocabulary.
Related post from earlier today.
Garbage Heavyweight Waste Management Gets Into Waste Gasification-to-Energy