plasma gasification

A plasma torch passes strong electric current under high voltage between two electrodes as an electric arc. Pressurized gas is ionized passing through the plasma created by the arc. The torch's temperature ranges from {{convert|2000|to|14000|C|F|-2}}.{{cite web |title=The Recovered Energy System: Discussion on Plasma Gasification |url=http://www.recoveredenergy.com/d_plasma.html |url-status=dead |archive-url=https://web.archive.org/web/20080923003407/http://www.recoveredenergy.com/d_plasma.html |archive-date=2008-09-23 |access-date=2008-10-20}} The temperature determines the structure of the plasma and forming gas.

{{Cite journal |last1=Bratsev |first1=A. N. |last2=Popov |first2=V. E. |last3=Rutberg |first3=A. F. |last4=Shtengel’ |first4=S. V. |year=2006 |title=A Facility for Plasma Gasification of Waste of Various Types |journal=High Temperature |volume=44 |issue=6 |pages=823–828 |bibcode=2006HTemp..44..823B |doi=10.1007/s10740-006-0099-7}}

The waste is heated, melted and finally vaporized. At these conditions molecular dissociation occurs by breaking apart molecular bonds. Complex molecules are separated into individual atoms. The resulting elemental components are in a gaseous phase (syngas). Molecular dissociation using plasma is referred to as "plasma pyrolysis."{{Cite journal |last=Huang |first=H. |author2=Lan Tang |author3=C. Z. Wu |date=2003 |title=Characterization of Gaseous and Solid Product from Thermal Plasma Pyrolysis of Waste Rubber |journal=Environmental Science & Technology |volume=37 |issue=19 |pages=4463–4467 |bibcode=2003EnST...37.4463H |doi=10.1021/es034193c |pmid=14572101}}

Smaller torches typically use an inert gas such as argon, while larger sizes require nitrogen. Electrodes vary from copper or tungsten to hafnium or zirconium, along with other alloys.

Feedstocks are most often refuse-derived fuel, biomass waste, both or biomedical waste and hazardous materials. The content and consistency of the waste directly impacts performance. Extracting treatable material improves consistency. Too much inorganic material such as metal and construction waste increases slag production, while decreasing syngas production. However, the slag is chemically inert and safe to handle. Shredding waste to create uniform particles is generally required. This creates an efficient transfer of energy which breaks down the material.{{cite web|url=http://science.howstuffworks.com/environmental/energy/plasma-converter.htm| title=How Stuff Works- Plasma Converter|access-date=2012-09-09| date=2007-04-25}}

Added steam supports steam reforming.

Pure synthesis gas consists predominantly of carbon monoxide (CO⁻) and hydrogen (H₂).

{{cite web

| url= http://www.netl.doe.gov/technologies/coalpower/gasification/gasifipedia/4-gasifiers/4-1-4-1a_westinghouse.html

| title= Plasma Gasification

| publisher= United States Department of Energy

| access-date= 2010-08-07

| archive-url = https://web.archive.org/web/20100813175346/http://www.netl.doe.gov/technologies/coalpower/gasification/gasifipedia/4-gasifiers/4-1-4-1a_westinghouse.html

| archive-date = 2010-08-13

| url-status = dead}}

Inorganic compounds in the waste stream melt, including glass, ceramics, and metals.

The temperature and lack of oxygen prevents the formation of many toxic compounds such as furans, dioxins, nitrogen oxides, or sulfur dioxide in the flame. However, dioxins form during cooling.{{Cite journal |last=Kirkok |first=Samuel K. |last2=Kibet |first2=Joshua K. |last3=Kinyanjui |first3=Thomas K. |last4=Okanga |first4=Francis I. |date=2020-09-24 |title=A review of persistent organic pollutants: dioxins, furans, and their associated nitrogenated analogues |url=https://doi.org/10.1007/s42452-020-03551-y |journal=SN Applied Sciences |language=en |volume=2 |issue=10 |pages=1729 |doi=10.1007/s42452-020-03551-y |issn=2523-3971}}

Metals can be recovered from the slag and sold. Inert slag produced from some processes is granulated and can be used in construction. A portion of the syngas feeds on-site turbines, which powers the plasma torches and thus supports the feed system.

Some plasma gasification reactors operate at negative pressure, although most attempt to recover{{Cite patent

| inventor-last = Camacho

| inventor-first = Salvador L.

| title = Method for the Gasification of Carbonaceous Matter by Plasma Arc Pyrolysis

| pubdate = 1980-01-01

| url = http://www.google.com/patents?id=WtwxAAAAEBAJ

}} gaseous and/or solid resources.

The main advantages of plasma torch technologies for waste treatment are:

• Preventing hazardous waste from reaching landfills

{{Cite patent

| inventor-last = Springer

| inventor-first = Marlin D.

| inventor2 = William C. Burns

| inventor3 = Thomas Barkley

| title = Apparatus and Method for Treating Hazardous Waste

| pubdate = 1996-07-09

| url = http://www.google.com/patents?id=FRMmAAAAEBAJ

}}

{{Cite patent

| inventor-last = Titus

| inventor-first = Charles H.

| inventor2 = Daniel R. Cohn

| inventor3 = Jeffrey E. Surma

| title = Arc Plasma-Melter Electro Conversion System for Waste Treatment and Resource ...

| pubdate = 1997-09-16

| url = http://www.google.com/patents?id=GBsnAAAAEBAJ

}}

• Some processes are designed to recover fly ash, bottom ash, and most other particulates, for 95% or better diversion from landfills, and no harmful emissions of toxic waste

{{Cite journal

| doi = 10.1016/j.wasman.2006.07.027

| pmid = 17134888

| issn = 0956-053X

| volume = 27

| issue = 11

| pages = 1562–1569

| display-authors = 4

| last = Lemmens

| first = Bert

|author2=Helmut Elslander |author3=Ive Vanderreydt |author4=Kurt Peys |author5=Ludo Diels |author6=Michel Oosterlinck |author7=Marc Joos

| title = Assessment of Plasma Gasification of High Caloric Waste Streams

| journal = Waste Management

| date = 2007

| bibcode = 2007WaMan..27.1562L

}}

• Potential production of vitrified slag which could be used as construction material

{{Cite journal

| volume = 49

| issue = 8

| pages = 2264–2271

| last = Mountouris

| first = A.

|author2=E. Voutsas |author3=D. Tassios

| title = Plasma Gasification of Sewage Sludge: Process Development and Energy Optimization

| journal = Energy Conversion and Management

| date = 2008

| doi=10.1016/j.enconman.2008.01.025

| bibcode = 2008ECM....49.2264M

}}

• Processing of biomass waste into combustible syngas for electric power and heat

{{Cite journal

| volume = 34

| issue = 4B

| pages = 1587–1593

| last = Leal-Quirós

| first = Edbertho

| title = Plasma Processing of Municipal Solid Waste

| journal = Brazilian Journal of Physics

| date = 2004

| doi=10.1590/S0103-97332004000800015

| bibcode=2004BrJPh..34.1587L

| doi-access = free

}}

or for synthesis into fuels or chemicals.

• Production of value-added products (metals) from slag

{{Cite journal

| volume = 16

| issue = 5

| pages = 417–422

| last = Jimbo

| first = Hajime

| title = Plasma Melting and Useful Application of Molten Slag

| journal = Waste Management

| date = 1996

| doi=10.1016/S0956-053X(96)00087-6

| bibcode = 1996WaMan..16..417J

}}

• Safe means to destroy both medical

{{Cite journal

| volume = 48

| issue = 4

| pages = 1331–1337

| last = Huang

| first = Haitao

|author2=Lan Tang

| title = Treatment of Organic Waste Using Thermal Plasma Pyrolysis Technology

| journal = Energy Conversion and Management

| date = 2007

| doi=10.1016/j.enconman.2006.08.013

| bibcode = 2007ECM....48.1331H

}} and many other hazardous wastes.{{Cite journal

| doi = 10.1088/0741-3335/47/5A/016

| issn = 0741-3335

| volume = 47

| issue = 5A

| pages = A219

| last = Tendler

| first = Michael

|author2=Philip Rutberg |author3=Guido van Oost

| title = Plasma Based Waste Treatment and Energy Production

| journal = Plasma Physics and Controlled Fusion

| date = 2005-05-01

|bibcode = 2005PPCF...47A.219T }}

• Gasification with starved combustion and rapid quenching of syngas from elevated temperatures can avoid the production of dioxins and furans that are common to incinerators
• Air emissions can be cleaner than landfills and similar to that of incinerators.

Main disadvantages of plasma torch technologies for waste treatment are:

• Large initial investment costs relative to that of alternatives, including landfill

{{Cite journal

| doi = 10.1109/TSTE.2010.2061242

| issn = 1949-3029

| volume = 1

| issue = 3

| pages = 125–130

| last = Pourali

| first = M.

| title = Application of Plasma Gasification Technology in Waste to Energy #x2014;Challenges and Opportunities

| journal = IEEE Transactions on Sustainable Energy

| bibcode = 2010ITSE....1..125P

| year = 2010

}}

and incineration.

• Operational costs are high relative to that of incineration.
• Wet feed stock reduces syngas production and increases energy consumption.
• Little or negative net energy production when taking into account all energy inputs.
• Frequent maintenance and limited plant availability.

{{main|Plasma gasification commercialization}}

Plasma torch gasification is used commercially for waste disposal{{Refn|

{{cite web

|url=http://www.peat.com/national_cheng.html

|title=National Cheng Kung University - Tainan, Taiwan

|publisher=PEAT International

|access-date=2009-04-09}}

{{Cite report

|last1=Williams |first1=R.B.

|last2=Jenkins |first2=B.M.

|last3=Nguyen |first3=D.

|title=Solid Waste Conversion: A review and database of current and emerging technologies

|page=23

|publisher=University of California, Davis, Department of Biological and Agricultural Engineering

| date=December 2003 |url=http://biomass.ucdavis.edu/pages/reports/Conversion-PhaseI_IWM-C0172.pdf

|archive-url=https://web.archive.org/web/20070415070400/http://biomass.ucdavis.edu/pages/reports/Conversion-PhaseI_IWM-C0172.pdf

|archive-date=2007-04-15}}

{{cite web

|url = http://www.zerowasteottawa.com/en/About-Project/

|title = About the Project

|publisher = A Partnership for a Zero Waste Ottawa

|access-date = 2009-04-10

|url-status = dead

|archive-url = https://web.archive.org/web/20090420003312/http://www.zerowasteottawa.com/en/About-Project/

|archive-date = 2009-04-20

}}

{{cite news

|first=Laura |last=Czekaj

|title=Mechanical problems plague Plasco

|newspaper=Ottawa Sun

|date=2008-12-07 }}

{{cite web

|url = https://www.afsoc.af.mil/News/story/id/123253735/

|title = AFSOC makes 'green' history while investing in future

|publisher = US Air Force Special Operations Command

|access-date = 2011-04-28

|url-status = live

|archive-url = https://web.archive.org/web/20110509083529/http://www.afsoc.af.mil/news/story.asp?id=123253735

|archive-date = 2011-05-09

}}

{{cite news

|title=INEOS Bio Commercializes bioenergy technology in Florida

|work=Biomass Program

|date=2011-11-21

|url=http://www1.eere.energy.gov/biomass/pdfs/ibr_arraprojects_ineos.pdf

}}

{{Cite web

| title = The Plasma Arc Waste Destruction System to Reduce Waste Aboard CVN-78, pg. 13

| publisher = Seaframe - Carderock Division Publication

| date = 2008

| url = http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA519815| archive-url = https://web.archive.org/web/20121201202200/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA519815| url-status = dead| archive-date = December 1, 2012}}

{{cite press release

|url = http://alternrg.com/press_release_94553

|archive-url = https://web.archive.org/web/20130307175931/http://www.alternrg.com/press_release_94553

|url-status = dead

|archive-date = March 7, 2013

|title = Alter NRG Announces Commissioning of Biomass Gasifier at Waste To Liquids Facility in China

|publisher = Alter NRG

|access-date = 2013-01-29

}}{{cite news|url=http://www.waste-management-world.com/articles/2013/04/plasma-gasification-waste-to-energy-air-products-teesside-uk-government.html|title=Second Plasma Gasification Plant for Teesside Following Government Deal|last=Messenger|first=Ben|date=12 April 2013|publisher=Waste Management News|access-date=29 July 2013|archive-url=https://web.archive.org/web/20150928033452/http://www.waste-management-world.com/articles/2013/04/plasma-gasification-waste-to-energy-air-products-teesside-uk-government.html|archive-date=28 September 2015|url-status=dead}}{{Cite press release|title=Air Products Will Exit Energy-from-Waste Business|date=2016-04-04|url=http://www.airproducts.com/Company/news-center/2016/04/0404-air-products-will-exit-energy-from-waste-business.aspx|access-date=2016-04-06}}{{Citation|title=Air Products abandons plans for plasma-based energy from waste plants in Tees Valley|date=2016-04-05|url=http://www.newpower.info/2016/04/air-products-abandons-plans-for-plasma-based-energy-from-waste-plants-in-tees-valley/|access-date=2016-04-06}}}} at five sites worldwide with a combined design capacity of 200 tonnes of waste per day, half of which is biomass waste.

Energy recovery from waste streams using plasma gasification is used in one or two installations treating 25–30 tonnes per day.

The US Navy employs the Plasma Arc Waste Destruction System (PAWDS) on its latest generation Gerald R. Ford-class aircraft carrier. The compact system treats all combustible solid waste.{{Citation | title = The Plasma Arc Waste Destruction System to Reduce Waste Aboard CVN-78, pg. 13

| publisher = Seaframe - Carderock Division Publication

| date = 2008

| url = http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA519815| archive-url = https://web.archive.org/web/20121201202200/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA519815| url-status = dead| archive-date = December 1, 2012}}

• Gasification
• Staged reforming
• Waste management
• Waste to energy
• Northeast of England Process Industry Cluster NEPIC

{{Reflist|30em}}

• [https://web.archive.org/web/20120302212301/http://www.dti.gov.uk/files/file33251.pdf Department of Trade and Industry - Using thermal plasma technology to create a valuable product from hazardous waste]

{{DEFAULTSORT:Plasma Arc Waste Disposal}}

Category:Sustainable technologies

Category:Plasma processing

Category:Thermal treatment