|
Page of the Padberg |
|
First Year Composition Web Page |
|
Literature Review The topic of this review is plasma gasification. It will focus on the process, goals, products, benefits, and limitations of the plasma gasification process. The first source I shall analyze is Demonstration plasma gasification/vitrification system for effective hazardous waste treatment. It starts out with a brief abstract describing the general process of plasma gasification. The paper states that this process is much more environmentally friendly than other types of thermal technologies. This introduction is a very nice summary of what plasma gasification is capable of doing and how it works. The paper then goes onto describing its main focus—hazardous waste. It describes the negative aspects of transporting hazardous waste for disposal. The main disadvantages stated include high transportation cost, environmental issues, national boundary crossing, and final storing/destruction. Once at its disposal site, this waste still posses the threat of leaching into the groundwater. If incinerated, however, the waste has to potential of emitting toxic substances in the flue gases. This section definitely strengthens the proposed solution of plasma gasification. A particularly useful part of this paper is the section that goes into detail of the plasma gasification process. This was tested in a pilot unit for disposal of waste via plasma gasification in Athens. The unit can be divided into eight main sections/parts. A waste feed system produces a constant flow of solid waste with no more than 50% moisture content. The plasma torch uses two electrodes to convert electrical energy into thermal energy to create the extreme heat needed for this process. The furnace is like giant crucible (.44 m wide, .87 m long) where the gasification takes place. The hot cyclone is a filtering system that removes dust and particulate matter from the gasses produces in the furnace. A secondary combustion chamber uses temperatures of 1100◦C + to fully combust CO and H2 so that no hazardous gases are formed. A water quench system then quickly cools the gasses to around 75◦C in order to prevent the formation of organic compounds that form in slow cooling. The Venturi/damper is used to again remove any particulate matter. The final process is the scrubber that filters and cleans the final gasses that will be given off. This section of the paper is quite detailed and technical. The paper concludes by stating the promising results of the trial in Athens. It states that, compared to European regulations, the plasma gasification process produces less pollution than other thermal treatment techniques for hazardous waste. It also goes on to describe the benefit and uses of the resulting slag and created electrical energy from the generated heat. It also lists other minor benefits including cheaper investment costs than equivalent incinerators. Two papers I look into seem to be written on the same topic: Arc-Gasification Plant Holds Promise for Power Production and Plasma to Vaporize Florida Landfill Waste. These sources are only small articles from magazines, but they do have a little bit of valuable information. They talk about a “$400-million plasma arc gasification facility” that is being built in St. Lucie County, Florida. This new plant will have the capabilities of processing 2,000 tons of new solid waste from the country along with an extra 1,000 tons from the landfill per day. The plant will produce electricity that will be put into the grid and at the same time process about 1 million tons of trash per year. The idea came from a plasma-arc gasification plant in Japan. The plant should be able to produce around 12 Megawatts of power from 1,000 tons of trash. One very interesting quote came from the former article, “If we took all of the municipal waste and collocated it with coal-fired power plants we could produce up to 5% of the nation's electricity from the plasma processing.” Tipping fees (the fee for dumping trash) can cost anywhere from $50 to $100+. “But by collocating the plasma facility on the same premises with a gas-fired power plant…[it can cost as low as] $20 to $40 per ton.” If the plant works a efficiently as planned the St. Lucie County landfill should be free of solid waste in about 18 years. An economic evaluation of a new technology for municipal solid waste treatment facilities seems to offer good incite. This article presents me new uses of the slag byproduct of plasma gasification: rock wool, floor tiles, roof tiles, insulation, landscaping blocks, road aggregate, or metallic content. The gasses produced can be harnessed to create electricity by secondary combustion. This source goes on to explain hypothetical cases of how much electricity the plasma gasification plant would produce and along with the slag material estimates the economical benefits of plasma gasification. The break even point for a plasma gasification plant in all these given hypothetical cases seems to be relatively low, in effect, proving the feasibility of building such facility. The paper concludes with the fact that plasma gasification is an emerging technology and that future endeavors will most likely be more efficient and cost effective. The last source in this paper was the first that I looked at. This is the source that made me want to research plasma gasification. Its title is The Prophet of Garbage, in the March 2007 edition of popular science. The article’s main focus is on the company Startech and its creator, Joseph Longo. It gives a brief history of how Longo got involved in this new technology, and then talks about his system. The difference between most other plasma gasification systems and Longo’s is that he designed it to accept almost anything you throw into it. The only thing it can’t break down is nuclear waste because it is indestructible. Like other plasma gasification machines the only byproducts are the obsidian-like material (hardened slag), “syngas” (synthetic gas), and of course lots of heat. But Longo doesn’t waste any of these precious byproducts. His machine will convert the syngas into usable fuels such as hydrogen, ethanol, and natural gas. The heat is used to generate electricity which powers the machine and extra is sent out onto the grid. The “glass” material can be used in many different applications most notably for bathroom tiles and high strength asphalt. Longo takes pride that his machine is self-sustaining. Once the cycle starts, the machine generates all the power it needs from its own generator. “The initial voltage is about equal to the zap from a police stun gun.” A Startech machine can handle anywhere from 2,000 to 3,000 tons of trash daily. Many other companies exist that want to capitalize on this new technology—Geoplasma, Recovered Energy, PyroGenesis, EnviroArc and Plasco Energy to name a few. Longo is especially enthusiastic about his work—“What’s so devilishly wonderful about plasma gasification is that it’s completely circular. It takes everything back to its fundamental components in a way that’s beautiful.” Startech is slightly ahead of other plasma gasification systems. It’s “Starcell” can convert syngas into eco-friendly fuel more efficiently and more economically than other systems. Unlike the other techniques which use multiple steps, Startech uses an efficient one-step process. With trash building up and landfills filling up, plasma gasification is truly the wave of the future. Not only does it solve the trash problem, but it also generates electricity, gasses, and glass like material that can be sold for profit. In a system like Startech’s, the facility could pay for itself in as little as ten years. Hey, it is better than burning that stuff or burying it underground.
Behar, Michael. "The Prophet of Garbage." Popular Science 270.3 (2007): 56-90. Hansen, Brett. "Plasma to Vaporize Florida Landfill Waste." Civil Engineering (08857024) 76.11 (2006): 32-3. Moustakas, K., et al. "Demonstration Plasma gasification/vitrification System for Effective Hazardous Waste Treatment." Journal of hazardous materials 123.1-3 (2005): 120-6. Powers, E. Michael. "Arc-Gasification Plant Holds Promise for Power Production." ENR: Engineering News-Record 257.1 (2006): 16-. Young, Gary C. "Zapping MSW with Plasma Arc. (Cover Story)." Pollution Engineering 38.11 (2006): 26-9.
|
|
Fresh Writing Research |
|
Created by Mike Padberg |