Plasma Technology for Waste Treatment

1
Plasma Technology for Waste Treatment

• International Conference on Incineration and
  Thermal Treatment of Waste
• May 14, 2007, Phoenix, AZ
• By Pierre Carabin, M. Eng.

2
Outline

• What is plasma?
• Plasma gas composition
• Plasma torches
• Commercial plasma applications
• Commercial Waste treatment plants
• Plasma Processes
• Air emissions

3
WHAT IS PLASMA?

• The fourth state of matter
• A mixture of
• Electrons
• Ions
• Neutral particles
• Ions and neutral particles have much higher mass
  than electrons, called heavy particles or heavy
  components (mH/me 1840)
• Some of the heavy particles are in an excited
  state
• Returning from excited state to neutral state
  (ground state) results in photon emission
• Photon emission responsible for luminosity of
  plasma

4
Electrical properties of plasma

• Negative and positive charges balance each other
• Plasma is electrically neutral. Property known as
  quasi-neutrality
• Plasma is electrically conductive
• Electrical conductivity comparable to that of
  metals at room temperature

5
Thermal and nonthermal plasma

• Thermal and nonthermal plasmas
• If Te TH then we have a thermal plasma
• If Te TH then plasma is nonthermal or
  nonequilibrium or cold plasma
• In a thermal plasma, there is Local Thermodynamic
  Equilibrium (LTE)
• LTE requires
• Te TH
• Excitation equilibrium
• Chemical equilibrium

6
Natural and man-made plasma

• Natural plasma
• Lightning strikes, high pressure, high luminosity
• Aurora borealis, low pressure, low luminosity
• Man-made plasma
• Flames, low ionisation level
• Glow discharge, low pressure

1 eV 7740 K
Source Boulos et al. Thermal Plasmas
Fundamentals and Applications V. 1, 1994, Vol. 1
7
Generating a thermal plasma

• High intensity arcs
• Free burning arcs, e.g. steel furnaces
• Wall stabilized arcs, e.g. arc lamp (lab studies)
• Convection-stabilized arcs, e.g. hot button
  plasma torches
• Magnetically stabilized arcs, e.g. plasma torches
  with magnetic field
• Thermal RF discharge
• Capacitive coupling HF electrical field
• Inductive coupling Time-varying magnetic field
• Microwave discharge
• The discharge is part of the MW circuit. Impacts
  plasma configuration and volume
• Low P operation results in deviation from
  equilibrium
• More recently, stable higher pressure plasma
  possible

8
Composition of a plasma gasMonoatomic Gas

• Ionization
• Ar ? Ar e-
• Ar ? Ar e-
• Ar ? Ar e-

Source Boulos et al. Thermal Plasmas
Fundamentals and Applications V. 1, 1994, Vol. 1
9
Composition of a plasma gasDiatomic Gas

• Dissociation
• N2 ? N N
• Ionization
• N2 ? N2 e-
• N ? N e-
• N ? N e-
• N ? N e-

Nitrogen
Source Boulos et al. Thermal Plasmas
Fundamentals and Applications V. 1, 1994, Vol. 1
10
Composition of a plasma gasGas mixtures - Air

• Dissociation
• N2 ? N N
• O2 ? O O
• Recombination
• N O ? NO
• N O2 ? N2
• Ionization
• NO ? NO e-
• N2 ? N2 e-
• N ? N e-
• N ? N e-
• O2 ? O2 e-
• O ? O e-
• O ? O e-
• Ar ? Ar e-
• Ar ? Ar e-

Source Boulos et al. Thermal Plasmas
Fundamentals and Applications V. 1, 1994, Vol. 1
11
Plasma arc and plasma gas temperatures
12
Plasma arc and plasma gas temperatures
13
Commercial Thermal Plasma Generating Devices
14
Types of plasma torches
Source Camacho, S.L., Industrial-worthy plasma
torches state of the art, Pure and Appl. Chem,
Vol 60, No. 5, pp 619-632, 1988
15
Generating a plasma Example of Solid Electrode
Type Torch

• Plasma is created by an electric arc discharge
  in a gas (e.g. air)
• NT torch - Two electrodes Cathode (electrons
  released), Anode
• Electric Arc is powered by the Power Supply
• The injected gas is heated by the Arc
• Air becomes very reactive

16
Commercial Plasma Applications

• Cutting and Welding
• Steel Melting Furnaces
• Thermal spray
• Atmospheric plasma spray (APS)
• Vacuum plasma spray (VPS)
• Chemical Vapour deposition (CVD)
• Physical Vapour deposition (PVD)

17
Commercial Plasma Cutting and Welding

• Plasma, generated between either a consumable or
  a non-consumable electrode and the work piece, is
  a used for both cutting and welding metals.
• Example A 100kW plasma cutting installation for
  cutting up to 5 thick steel plate.

18
Commercial Plasma Plasma Spray

• Plasma jets generated by a non-transferred arc
  torch are used to melt metal or ceramic powder
  and accelerate the molten droplets towards a
  target.
• On the target, the numerous molten droplets splat
  and solidify to form a new layer similar in
  composition to the original powder.
• Plasma spray represents a 3 billion per year
  global industry.

19
Commercial PlasmaMaterials Production Examples

• Acetylene production, 120,000 tpy.
• Developed in 1939 by Huels
• The 19 furnaces, each equipped with a 10 MW
  plasma torch, converts natural gas into
  acetylene.
• Titanium dioxide pigment, 80,000 tpy
• Developed by the British company TIOXIDE
  (Greatham, UK)
• TiO2 pigment is produced by combustion of TiCl4
  in an oxygen plasma flame.
• Plasma Cupola for the Melting of Scrap Iron, 50
  tph
• Installed by General Motors in 1989 at a plant in
  Defiance, USA
• A cupola, equipped with six 2 MW plasma torches,
  is used for the melting of scrap iron and loose
  cast iron borings.
• The use of the plasma torches permits the charge
  of unbriquetted fines such as chips or borings.

20
Commercial Plasma Melting Furnaces

• Production of steel, ferro alloys, magnesium,
  titanium, ferrochrome, etc. at power levels up
  162MW.
• Graphite arc furnaces using AC or DC current are
  used
• Current can reach several kAmps

21
Advantages of Plasma Systems

• High temperatures, presence of ions, free
  electrons and UV allow for highly efficient waste
  destruction and clean energy production
• An independent heat source allows for treating a
  wide variety of waste types
• The high intensity plasma heat allows for
  designing compact systems
• Potential GHG reduction since heat is generated
  by electricity instead of fossil fuels
• No by-products (reduced by-products)

22
Plasma Disadvantages / Challenges

• New technology perception
• Control of NOx emissions from air torch
• Developing markets for slag
• Scale-up risks
• Limitation of size of commercially available
  torches

23
Thermal Plasma Systems Applications to Waste
Treatment

• Fly Ash Vitrification
• Hazardous Waste Destruction
• Demilitarisation
• Low level radioactive waste
• ASR
• Biomedical waste
• Shipboard waste
• MSW

24
Waste Treatment Plasma PlantsA Partial List
Source R.W.Beck Inc report, City of Honolulu
Review of Plasma Arc Gasification and
Vitrification Technology for Waste Disposal
25
Plasma System Block Diagram
Plasma Combustion
Plasma Close Coupled Gasification
Plasma Gasification
Air (Optional)
Waste
Air
Electricity
Waste
Electricity
Waste
Electricity
Gasification
Slag
Combustion
Gasification
Slag
Slag
Post-combustion
Air (fuel)
Energy Recovery
Synthesis Gas Cleaning
Steam
Energy Recovery
Steam
Post-combustion/Energy Recovery
Off-Gas Treatment
Off-Gas Treatment
Steam/ Electricity
Air
Off-Gas to Stack
Off-Gas to Stack
Off-Gas to Stack
26
Plasma Ash Vitrification Systems

• Europlasma
• Ebara
• Tetronics
• Kawasaki Heavy Industries
• Kobe Steel
• Hitachi Zosen

27
Europlasma Cenon Plant for Fly Ash Vitrification
Capacity 10 TPD
Guihard, IT3-2002, New Orleans, LA
28
Ebara Fly Ash Melting (Vitrification)
http//www.gec.jp/JSIM_DATA/WASTE/WASTE_3/html/Doc
_461.html
29
Kawasaki Heavy Industries
http//www.gec.jp/WASTE/data/waste_C-3.html
30
Europlasma Inertam Process for Asbestos
Vitrification
Capacity 22 TPD
Guihard, IT3-2002, New Orleans, LA
31
Hazardous and Special Waste Treatment

• Retech - LLRW
• MSE Old munitions
• Vanguard Research
• IET LLRW, biomedical waste
• PyroGenesis Shipboard waste

32
Retech Process for LLRW
Capacity 200-300 kg/h
Wenger et al., IT3-2002, New Orleans LA
33
Retech PAHWTS (Plasma Arc Hazardous Waste
Treatment System) Process
34
MSE MPTS (Mobile Plasma Treatment System) Process
Henningsen., IT3-2002, New Orleans LA
35
PEPS (Plasma Energy Pyrolysis System) Process
Source R.W.Beck Inc report, City of Honolulu
Review of Plasma Arc Gasification and
Vitrification Technology for Waste Disposal
36
PyroGenesis PAWDS Process for Shipboard Waste
? 8 meters ?
? 12 meters ?
37
PyroGenesis PAWDS System Description
Lint like milled waste
Plasma 5,000 C
38
Gasification

• The carbon in waste reacts with steam and
  sub-stoichiometric oxygen (from air)
• Main Gasification Reactions
• C O2 -gt CO2 (exothermic)
• C H2O -gt CO H2 (endothermic)
• C CO2 -gt 2 CO (endothermic)
• CO H2O -gt CO2 H2 (exothermic)
• Resulting synthesis gas (syngas) can be used for
  energy production in IC engines or turbines,
  synthesis of chemicals, hydrogen production, etc.

39
Gasification in the World

• 160 active commercial-scale gasification plants
  in the world, 417 gasifiers
• 58,100 MW syngas produced worldwide
• Average gasification plant produces over 360 MW
  syngas
• 10 annual growth
• Source US Department of Energy Survey 2000

40
IET Process
Source Quapp et al., IT3-2003, Orlando, FL
41
IET Furnace
42
MSW Gasification by Plasma

• Hitachi Metals (Westinghouse Plasma)
• EER
• Plasco
• Many others promoting and developing
• Geoplasma
• Startech
• PyroGenesis
• IET

43
Hitachi Metals (Westinghouse) Plasma Assisted
Gasifier
Source Hitachi Metal
44
EER Process
Source EER Website
45
PyroGenesis PRRS - Plasma Resource Recovery System
PyroGenesis patented two-stage gasification
system combines a graphite arc furnace with a
plasma eductor
Vitrification

• Gasification

Thermal conversion of organic matter into
synthesis gas consisting primarily of CO and H2
Inorganic material is melted at 1,600C to
produce inert slag that is safe for use in
various applications
46
Plasco Process
Source Fisby et al. IT3-2003, Orlando FL
47
Plasco Process Electricity Generation
Source Plasco Web Site
48
Example Syngas compositionPyroGenesis Plasma
gasification of MSW
49
Example Syngas CompositionIET
Source Quapp et al., IT3-2003, Orlando, FL
50
Example Syngas CompositionEER
Yibin, Israel
Source EER website
51
Air Emission Results ExamplesPEPS System
Source R.W.Beck Inc report, City of Honolulu
Review of Plasma Arc Gasification and
Vitrification Technology for Waste Disposal
52
Air Emissions and DRE ExamplesIET Evtec Tests
Source Quapp et al., IT3-2003, Orlando, FL
53
Air Emission ExamplesPyroGenesis PAWDS
(Operating at Sea)
54
Example Emissions from PyrogenesisPRRS Process
1 Rm3 1 reference cubic meter at 25C, 101.3
kPa, dry gas, 11 O2
55
Air Emissions ExamplesDioxin Emissions from MPTS
MACT standard 0.2 ng/dscm-TEQ EU standard 0.1
ng-TEQ/dscm
Henningsen, IT3-2002, New Orleans LA
56
Thank You!