Nonthermal Plasma Application for Environmental Control

1
Non-thermal Plasma Application for Environmental
Control

• Abstract authors Alexander Fridman and Alexander
  Gutsol
• University of Illinois at Chicago
• Presented by Johnny Liu
• 2002 Nov.

2
Outline

• General description of Air pollutants
• Conventional VOC removal techniques
• Non-thermal plasma technologies
• Application of dielectric barrier discharge
• Conclusions

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General Description of Air Pollutants

• Acid gases, such as SOx, NOx, HCl etc.
• Ozone depletion substances, such as FreonTM,
  HalonTM etc.
• Volatile organic compounds (VOC), such as
  toluene, phenol, trichloro- ethylene etc.
• Toxic gases, such as Hg, dioxins etc.

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Types of VOC
TLV, threshold level value in ppm reference
K. Urashima and J.S. Chang, IEEE Trans.
Dielectrics and Electrical
Insulation, Vol. 7, No. 5, October 2000.
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Conventional VOC removal techniques
UV oxidation
Thermal plasma
Thermal oxidation
reference K. Urashima and J.S. Chang, IEEE
Trans. Dielectrics and Electrical
Insulation, Vol. 7, No. 5, October 2000.
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Non-thermal plasma technologies
Non-thermal plasma The electrons attain very
high energies, while the background gas remains
at ambient temperature. Mechanism of VOC
treatment - highly effective in promoting
oxidation - enhance molecular dissociation -
produce free radicals to enhance chemical
reaction Advantages of non thermal plasma
method - high removal efficiency - high energy
yields - good economy
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Application removal of Formaldehyde (HCHO)

• Removal mechanisms
• Direct removal caused by the collision of
  electrons with HCHO.
• Reaction between HCHO molecules and gas-phase
  radicals.

reference M. B. Chang and C.C. Lee, Environ.
Sci. Technol. 1995, 29, p181-186
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Dielectric barrier discharge
60 Hz 3 kVA
All the tests were completed at 1 atm, ambient
temperature (24 2 C) .
reference M. B. Chang and C.C. Lee, Environ.
Sci. Technol. 1995, 29, p181-186
9
Result 1
The gas streams contain 100 ppm HCHO, 5 O2, 1
H2O (gas), and N2 as the carrier gas.
reference M. B. Chang and C.C. Lee, Environ.
Sci. Technol. 1995, 29, p181-186
10
Result 2
The gas streams contain 110 ppm HCHO, 20 O2, 2
slpm of total gas flow rate.
reference M. B. Chang and C.C. Lee, Environ.
Sci. Technol. 1995, 29, p181-186
11
Result 3
The gas streams contain 100 ppm HCHO, 1 H2O, and
N2 as the carrier gas.
reference M. B. Chang and C.C. Lee, Environ.
Sci. Technol. 1995, 29, p181-186
12
Conclusions
Emissions of volatile organic compounds into the
atmosphere have the potential to cause adverse
effects on human health and the environment. The
HCHO can be effectively removed via applying
dielectric barrier discharge plasma. Destruction
of VOC molecules can be achieved by both direct
electron attack and indirect gas-phase radical
reaction mechanisms.