Κυριακή 11 Ιανουαρίου 2009


Τα απορρίματα δεν καίγονται αλλά με την δημιουργία ενός τόξου με θερμοκρασία τάξεως 12-14000 βαθμών Κελσίου εξαερούνται σε καύσιμο αέριο δια του οποίου παράγεται στην συνέχεια ηλεκτρική ενέργεια. Ενα άλλο πλεονέκτημα αυτής της μεθόδου είναι ότι δεν υπάρχουν σχεδόν κατάλοιπα με αποτέλεσμα να μη χρειάζονται χώροι εναπόθεσης. Το ελάχιστο υπόλοιπο που παραμένει σε μορφή γυαλιού μπορεί να χρησιμοποιηθεί στην βιομηχανία.

Οι εγαταστάσεις πλάσματος δεν χρειάζονται καύσιμο για να λειτουργήσουν, αυτοτροφοδοτούνται από το καύσιμο αέριο που παράγουν. Χρειάζονται καύσιμο μόνον όταν γίνεται η εκκίνηση τους και μετά την εξαέρωση των πρώτων απορριμάτων αυτοτροφοδοτούνται.

Πολύ εδιαφέρουσα περίπτωση χρήσεως της μεθόδου εξαέρωσης δια του πλάσματος είναι η δημιουργία εργοστασίων παραγωγής ηλεκτρικής ενεργείας με την χρήση λιγνίτου γιατί το αποτέλεσμα έχει σχέση με τον καθαρό ουρανό χωρίς τις δυσάρεστες καταστάσεις που δημιουργούν τα λειτουργούντα εργοστάσια ή και τα νέα που προγραματίζονται.

Είναι δυνατή η μεταποίηση και μονάδων παλαιών που σήμερα ανεπιθύμητα λειτουργούν. Ηδη προς αυτήν την κατεύθυνση στις ΗΠΑ γίνονται παρόμοιες μετασκευές.

Μια λεπτομερής παρουσίαση παρατίθεται παρακάτω με απαντήσεις σε κρίσιμα ερωτήματα και επίσης που υπάρχουν σήμερα εργοστάσια με πλάσμα.

PLASMA GASIFICATION

Plasma gasification is the gasification of matter in an oxygen-starved environment to decompose waste material into its basic molecular structure. Plasma gasification does not combust the waste as incinerators do. It converts the organic waste into a fuel gas that still contains all the chemical and heat energy from the waste. It converts the inorganic waste into an inert vitrified glass.
Plasma is considered a 4th state. Electricity is fed to a torch, which has two electrodes, creating an arc. Inert gas is passed through the arc, heating the process gas to internal temperatures as high as 25,000 degrees Fahrenheit. The following diagram illustrates how the plasma torch operates.
The temperature a few feet from the torch can be as high as 5,000-8000Ί F. Because of these high temperatures the waste is completely destroyed and broken down into its basic elemental components. There are no tars or furans. At these high temperatures all metals become molten and flow out the bottom of the reactor. Inorganics such as silica, soil, concrete, glass, gravel, etc. are vitrified into glass and flow out the bottom of the reactor. There is no ash remaining to go back to a landfill.
The plasma reactor does not discriminate between types of waste. It can process any type of waste. The only variable is the amount of energy that it takes to destroy the waste. Consequently, no sorting of waste is necessary and any type of waste, other than nuclear waste, can be processed.
The reactors are large and operate at a slightly negative pressure, meaning that the feed system is simplified because the gas does not want to escape. The gas has to be pulled from the reactor by the suction of the compressor. Each reactor can process 20 tons per hour (tph) compared to 3 tph for typical gasifiers. Because of the size and the negative pressure, the feed system can handle bundles of material up to 1 meter in size. This means that whole drums or bags of waste can be fed directly into the reactor making the system ideal for large scale production.
The gas composition coming out of a plasma gasifier is lower in trace contaminants than with any kind of incinerator or other gasifier. Because the process starts with lower emissions out of the reactor it is able to achieve significantly lower stack emissions. The gasifier doesn't care about the amount of moisture in the waste. The moisture consumes energy to vaporize and can impact the capacity and economics, however, it will not affect the process.

People have many questions about a "waste processing plant".

Environmental groups are rightly concerned about emissions and byproducts.

Waste processing is something nobody wants to be done near them. (NIMBY - Not In My Back Yard).

Some of the more frequent questions are addressed here and throughout this website.

Instead of land filling or incinerating MSW, this new facility, using a Plasma Gasification process, converts all types of waste streams (gas, liquid or solid) into a fuel gas composed primarily of carbon monoxide, hydrogen, nitrogen and water. This fuel gas is then used to generate electrical power. The process is very efficient. 99.9% of the waste that is input into the system is converted to energy or other salable products. Typical gasification or incineration plants generate up to 30% residual waste that must be hauled to a landfill. The Thermal Transformation process uses a high temperature (up to 8,000 degrees Fahrenheit.) plasma arc technology to "gasify" carbon based materials into an energy rich fuel gas with a BTU value about 1/3 that of natural gas. The fuel gas is then cleaned and cooled so that it can be used in a gas turbine to generate electricity. Non carbon based material is primarily transformed into vitrified glass or recyclable metal.

Does waste have any value? Is it a Liability or an Asset?

Waste is not a liability. It is one of the most significant and valuable resources we have. Society has made waste a liability because of the way it has chosen in the past to handle the waste. The Recovered Energy System™ treats waste as the valuable asset that it is and recovers and recycles over 99.9% of this valuable asset

Isn't this "Plasma Gasification" process the same as incineration? Does the plasma gasification process "burn" the waste?

Incineration is the burning of carbon based (organic) material in an oxygen-rich environment, much the same as burning wood in a wood stove. Organic matter contains energy. The burning process requires a large amount of oxygen (O2). The carbon contained in the organic matter reacts with the oxygen to form carbon dioxide (CO2) and water (H2O). The combustion is highly exothermic and releases the energy in the organic material in the form of heat. The combustion of the carbon-based material is incomplete, leaving ash, tar and char that contains heavy metals and toxic substances requiring it to be sent to a special landfill. Non carbon based (inorganic) materials such as metal, glass, soil, concrete, silica, etc. are not affected by the burning process and become part of the ash. The total unburned material left over can be as high as 30% by weight. Incineration results in high levels of tars, furans, NOx, dioxins and sulfur dioxide, which are expensive to clean from the exhaust.
Plasma Gasification is not incineration and it does not burn the waste. It is the transformation of carbon based material in an oxygen-starved environment using an external high heat source (plasma) to produce a fuel gas (also called a syngas) that can be used in other applications. Even though the temperatures are much higher than with incineration, the organic material does not burn because there is not enough oxygen. The process controls the amount of oxygen and allows only enough oxygen to form carbon monoxide. The organic matter is transformed to a fuel gas composed of carbon monoxide (CO) and hydrogen (H2). Only a small amount of energy is released when the carbon and oxygen molecules combine. The carbon monoxide still contains substantial chemical energy and can be used in a variety of ways. The high temperatures of the Plasma Gasification process melt metals, glass, silica, soil, etc., which flow out of the bottom of the reactor. The metals are recycled and the other inorganic materials become vitrified (molten) glass. Because of the high temperatures and lack of oxygen there are no tars, dioxins or furans and Nox and Sox are much lower. The net result is that all the waste is converted to salable products.

What is Plasma?

Plasma is a gas that is essentially ionized, superheated air. A special plasma torch heats regular air to internal temperatures (inside the torch) as high as 25,000 degrees Fahrenheit and external temperatures (point of contact with the material) as high as 8,000 degrees Fahrenheit. The source of energy for the torch is electricity. The superheated air is used to thermally decompose whatever it comes in contact with. Steel foundries have used plasma to smelt steel for many years. Plasma is a well-established technology in many industries.

What is the difference between Plasma Gasification and standard gasification? Standard gasification technologies operate the reactor in the 700 - 1500 degrees Fahrenheit. range. They do not use any external heat source and rely on the process itself to sustain the reaction. Normal gasifiers are really "partial combustors" and a substantial portion of the carbon is combusted just to support the reaction. Their gasification process produces a fuel gas similar to the gas produced by the plasma process, although it is much dirtier and contains char and tars. The lower temperatures cannot break down all the materials. With standard gasification many materials must be sorted out of the waste stream before the reactor and landfilled or processed in other ways. Because of the low temperature used, the gas that is produced by a standard gasifier has tars that are difficult to remove and other contaminants that must be further cleaned up. Char residue remains that is up to 15% of the weight of the incoming material and must still be landfilled. In addition to these drawbacks, most standard gasification systems cannot feed MSW directly from the truck. The refuse must be dried to an acceptable moisture content, and processed into a uniform size and consistency further adding to the cost and complexity. Plasma gasification uses an external heat source to gasify the waste, resulting in very little combustion. Almost all of the carbon is converted to fuel gas. Plasma gasification is the closest technology available to pure gasification and is a "true gasifier". Because of the temperatures involved all the tars, char and dioxins are broken down. The exit gas from the reactor is cleaner and there is no ash at the bottom of the reactor. The Plasma gasifier can process any type of waste, does not require sorting and is not impacted operationally by moisture.

Why hasn't Plasma Gasification been done before?

Plasma gasification has been used in the steel, wood and other industries for many years. A general abundance of inexpensive electrical power and ample landfills have limited the commercial viability of this technology for MSW. There are a large number plasma gasification MSW plants in operation throughout the world in various industries. Several plasma gasification plants are in operation in North America operating on hazardous waste. With the demand for energy always on the rise, closures of landfills and the high cost of opening new ones, the time has come for our Recovered Energy System™ using plasma technology to come to the forefront.

What is "Fuel Gas" and what is it's the Btu value?

"Fuel Gas" is the name used to refer to the gas coming from the organic waste out of the reactor and used to fuel the gas turbine. It is composed mostly of carbon monoxide and hydrogen and has a Btu value of 320 Btu per cubic foot, or about 1/3 the Btu value of methane (natural gas). When combined with the nitrogen and water in the gas stream, the fuel gas has an overall Btu value of about 160 Btu per cubic foot. This can vary someone depending on the feedstock and moisture content.

Are there gas turbines that will operate on such low Btu gas?

Yes. Many of the turbine manufacturers have designed turbines specifically for low Btu syngas. In fact, the same turbine rated for methane at X MW will have a higher MW rating with syngas.

Is the electricity produced by plasma gasification "green electricity"?

Green electricity is defined as electricity produced from renewable sources. Typically we think of solar, wind and geothermal power when we think of renewable energy. However, MSW and other wastes renew themselves (with our help) and the energy produced from waste is green electricity. There are several companies that market green electricity. They generally do not market power from incinerators because of the negative environmental impact and bad reputation of incinerators. However, plasma gasification does not have the negative impact of incinerators and will eventually be sold by the distributors of green electricity.

Doesn't the plant generate carbon dioxide? Does this carbon dioxide contribute to the greenhouse effect?

When the CO goes through the gas turbine it is combined with more oxygen and energy is released. The CO becomes CO2 or carbon dioxide. Coal, diesel and natural gas power plants produce CO2 and contribute to the greenhouse effect. These power plants are using petroleum based fuels that are introducing new CO2 into the environment. The Recovered Energy System™ does not contribute to the greenhouse effect because it does not use new hydrocarbons as a fuel source. Our process simply releases CO2 that was already part of the base of organic material.

How much energy is contained in waste?

The United States produced 230 million tons of MSW in 1999. Industrial non-hazardous waste added another 7.6 billion tons. Medical waste and hazardous waste also add significant volumes of waste. If just the MSW were converted into electricity using our process it would generate over 30,000 mWh of electricity or an amount equal to more than 15 large coal fired power plants. For a plant processing 126 tons of waste per hour, more than 135 megawatts per hour of "green" power will be produced. After powering it's own needs this pant would export 1 megawatt for each ton of waste processed.

How will a Recovered Energy System™ plant affect the local citizens and the environment?
The Recovered Energy System™ is very environmentally sensitive recycling process. It will provide a long-term solution for disposing of residential, commercial, and industrial wastes. It will stabilize disposal fees, eliminate the threat of pollution associated with landfills or incineration. At the same time it will create jobs and provide a long-term income to the municipalities it serves.

How can you call this process recycling?

The American Heritage dictionary defines recycling as the extraction and reuse of useful substances found in waste. The Recovered Energy System™ is the ultimate form of recycling. Over 99.9% of the waste processed is recycled into other products and energy that can be reused. This is all done with no sorting and less effort.

What types of waste can be processed?

The Recovered Energy System™ can process any type of waste with the same environmental cleanliness and complete breakdown and recycling efficiency. No pre-treating, sorting, or extra handling is required. Household garbage, yard waste, glass, incinerator ash, oil waste sludges, plastics, paints, contaminated soils, tires, etc. can all be processed and recycled.

Can the plant process hazardous waste?

The same technology can, with only procedural and permitting changes safely and profitably process hazardous waste. Hazardous waste will be processed only after proper permits can be obtained. Waste that is classified "Hazardous" will not be permitted to be processed with "non-hazardous" materials as they are handled in a completely different manner. Strict rules and guidelines will be enforced that prevent haulers from delivering hazardous materials, unless the facility is permitted for this type of waste. The Recovered Energy System™ will process and recycle a far greater range of wastes than were previously possible. Hard to dispose of items such as tires, used oil, oil contaminated soils, auto shredder residue, coal fines, incinerator ash, most construction and demolition waste, even metal and glass will be recycled.

Where will the plant be located?

The plant can be located at any site that has adequate services and access. No visual evidence will be present that will indicate that garbage and waste is processed.

Will there be any odors from the plant?

The receiving area for all of the refuse is enclosed and kept at a negative pressure. The air required for the process is pulled through the receiving and storage areas thereby pulling the odors into the gasifier. The off-hours storage is contained inside a building and is cycled every 3-4 days. Only enough material is stored to operate the plant when it is not accepting wastes, such as at night and weekends. Odors are first minimized and then contained and processed along with the waste.

What happens if the facility breaks down or doesn't work properly?

At no time will the municipality or citizens be affected by scheduled or unscheduled shutdowns. Many operational contingencies and procedures are engineered into the facility design. These contingency plans are reviewed and approved by the local waste management authority. This ensures that waste and all byproducts are handled properly should any unforeseen events occur that cause the plant to go off-line. Also the turbines are set up so that they can run on natural gas if there is a problem with the waste plant.

Who watches over the facility to ensure it is operated in an environmentally responsible manner?

In addition to the regulatory agencies that the facility is subject to, a community advisory group, consisting of local residents will be formed to monitor the plants activities. This group will be funded by the facility and will monitor all operations and environmental compliance. Further, all emissions compliance data will be available on-line on a web page hosted by the company.

How will the facility get its waste?

The facility will receive waste in the same manner as a landfill or transfer station. Municipalities will still be responsible to pickup waste and haul it to the facility or negotiate with private haulers for this service. The participating municipalities will sign waste contracts for a negotiated period to bring the waste to the facility and pay a negotiated tipping fee. Where possible the plant could be located on a rail line or a shore line to receive waste by barge.

Won't we lose the income and positive environmental impact from the recycling program that we now have?

For some items the collecting and sorting out of the "recyclable" item such as glass and metal costs more than the income that is realized by the sale of such materials. The Recovered Energy SystemTM is a more efficient "recycling" method. We do not, however, discourage traditional recycling programs. We simply offer the municipality an option to decide which items to recycle traditionally and which to send unsorted to the facility for 100% recycling into energy or useful byproducts.

What risks are there if this plant is built in my town?

The facility does not create any new waste streams and all emissions are closely monitored. The design of the plant incorporates the latest technologies for modern storage tanks, containment systems and fire control systems. Modern control systems assure safe operation and proper reaction in the event of an upset. Risks are actually much lower than the risks of conventional landfills.

Locations

The first plasma based waste disposal system in the USA is scheduled to come into operation in St. Lucie County, Florida. The county states that they hope to not only avoid further landfill, but completely empty their existing landfill—4.3 million tons (3.9 million metric tons) of waste collected since 1978—within 18 years.[1] The plant is scheduled to come into operation in 2009, and to produce 600 tons (550,000 kg) of solid rubble from around 3000 tons (2.7 million kg) of waste per day at around 5500°C. St. ... The short ton is a unit of mass equal to 907. ... A tone or metric ton (symbol t), sometimes referred to as a metric tone, is a measurement of mass equal to 1,000 kilograms. ... Year 1978 (MCMLXXVIII) was a common year starting on Sunday (link displays the 1978 Gregorian calendar). ... “Kg” redirects here. ...
The city of Tallahassee, Florida has signed the largest plasma arc waste to energy contract (35MW) to date with Green Power Systems to process 1,000 tons daily from the city and several surrounding counties. Completion of the project is scheduled for October 2010. Location in Leon County and the state of Florida Coordinates: , Country State County Leon Government - Mayor John Marks Area - City 254. ...
Three similar but smaller plants are in operation in Japan -- a 166 ton/day "pilot" plant in Yoshii, co-developed by Hitachi Metals Ltd. and Westinghouse Plasma, which was certified after a demonstration period in 1999-2000; a 165 ton/day plant in Utashinai City, completed in 2002; and a 28 ton/day plant commissioned by the twin cities of Mihama and Mikata in 2002 [Williams, Jenkins & Nguyen (2003), "Solid Waste Conversion: A review and database of current and emerging technologies", University of California Davis, Department of Biological and Agricultural Engineering, Special Report prepared for the California Integrated Waste Management Board pursuant to Interagency Agreement – IWM-C0172: 23, <http://biomass.ucdavis.edu/pages/reports/Conversion-PhaseI_IWM-C0172.pdf>]. An unknown source has stated that at least one of the plants in Japan has not managed to produce more energy than it consumes. Two similar facilities run by different companies in Australia and Germany closed after failing to meet emissions standards.[citation needed]
EnviroParks Limited [2] plan (31/9/07) a consortium to build an Organic Park in Tower Colliery at Hirwaun, South Wales. This includes Plasco Energy Group Inc, plasma gasification plant with Northern Irish anaerobic digestion specialists B9 Organic Energy, US-owned agricultural waste specialists Agritec Systems Ltd and York-based oil processing specialists Ebortec Ltd, as well as Austrian firm Biodiesel Technologies GmbH. This could eliminate the need for future incinerators (EfW facilities) to divert Municipal Solid Waste from Landfill.
As much as £60 million is being put into the project by EnviroParks Ltd and its partners, to establish organic waste and mixed waste treatment facilities next to the Tower Colliery at Hirwaun. The Hirwaun site itself is large enough for the processing of over 250,000 tonnes of non-hazardous waste a year. Initially, though, an anaerobic digestion plant will be designed to handle 50,000 tonnes of organic wastes a year, with the potential for a 100% expansion.
Advanced Plasma Power [3] have built a plasma gasification modular test facility in Farringdon, Oxfordshire, England that uses Refuse Derived Fuel RDF feedstock to produce hydrogen, syngas, energy and vitrified gravel. Refuse-derived fuel (RDF) or solid recovered fuel (SRF) is a fuel produced by shredding municipal solid waste (MSW) or steam pressure treating in an autoclave. ... RDF can refer to: Radical Dance Faction a band from the UK. Radio direction finder, a device for finding the direction to a radio source. ...
Concerns

Dioxin emissions are possible from plasma arcs when chlorine is present. Process gas cleanup is necessary when gasifying waste streams such as municipal waste streams known to contain heavy metals, chlorine/fluorine, sulfur, etc. Dioxin is the common name for the group of compounds classified as polychlorinated dibenzodioxins (PCDDs). ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...
In 2004, the city of Honolulu considered a plasma arc/torch proposal for processing municipal solid waste. The city's Department of Environmental Services evaluated the plasma process and found that using plasma arc/torch technology would significantly boost waste disposal costs without offering worthwhile environmental advantages.[3] City of Honolulu press release, March 30, 2004: City to Brief Council on Plasma Arc Recommendations for Landfill. It is important to note, that at this stage, no municipal-waste disposal sized plasma arc facilities have as yet been constructed, and therefore they pose a considerable technological and budgetary challenge to even the largest municipalities. While some believe Federal funding is required to make better progress on this means of waste disposal (which is scientifically not the same principle as waste incineration), others note that basic thermodynamics show electricity costs to be unavoidably high when processing wet wastes such as municipal wastes. Honolulu as seen from the International Space Station Honolulu is the largest city and the capital of the U.S. state of Hawai‘i. ...
The technology of using plasma arc to treat waste has not changed significantly in principle from initial concept inception. Practical (limited use of land space for land-fills), technological (large-scale use of technology versus small-scale, e.g. plasma arc is currently favoured as a means to destroy medical and hazardous waste), logistical (transportation infrastructure requirements) and budgetary considerations all affect the viability of individual projects. Plasco Energy Group Inc. is nearing completion in approx. March 2007 of a plasma-arc waste demonstration plant in Ottawa, Canada at the Trail Road Landfill, to process 100 metric tonnes per day volume of municipal solid waste. Unlike other plasma waste processing facilities, PLasco Energy Group's process does not use plasma to destroy waste, but rather to refine gases produced during gasification, in order to allow them to be used to run an internal combustion gas engine and produce industry-leading low emissions. On October 24, 2007, the Plasco Trail Road facility began delivering power to the grid.
An issue regarding plasma systems is in the life of their liners. The liner is an important aspect of separating the high interior temperatures of the plasma system from the [metal] shell of the plasma container. Liners are highly susceptible to both chlorine attack and to local variabilities in [high] temperatures, both of which would be found with typical municipal waste systems, and are not likely to last more than a year in service.