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Application of Nonthermal Plasma to Chemical
Reactions Abstract authors S. Futamura, H.
Kabashima, and H. Einaga National Institute of
Advances Science and Technology Presented by
Yu-Chun Chen November 11, 2002
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Introduction

• Applicability of non-thermal plasma (NTP) to
  chemical reactions
• 1. Removal of hazardous air pollutants
• (HAPs)
• 2. Hydrogen production from small
• molecules
• 3. Hydrocarbon reformimg

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Outline

• From the authors
• NTP
• FPR
• SDR
• Results
• Conclusions

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From The Authors

• Plasma-generating methods greatly affect average
• electron temperature and distribution of
  active
• species formed in NTP.
• Hybridization of NTP with catalyst/
  photocatalyst
• is mandatory to increase the energy efficiency
  of
• the reaction system.
• This paper Comparison of reactor effect between
• FPR and SDR of conversions of
  trichloroethylene
• (TCE) and CH3Br , and H2 production from H2O
• and CH4 (both in N2)

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NTP

• NTP has been investigated in control of
• 1. Volatile organic compounds (VOCs)
• 2. Nitrogen oxides (NOx)
• 3. Hydrogen production
• 4. Syntheses of methanol, synthesis gas
• Merit
• Gas temperature kept at ambient temperature
  in spite of large magnitudes of electron energies

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NTP

• Even without gaseous oxygen, many of VOCs can be
  easily decomposed.
• Amount of active oxygen species in NTP are not
  necessarily large, depending on the
  plasma-generating method.
• Reason The short lifetime of the high-energy
  electron and the partial decomposition of active
  oxygen species caused by local temperature inside
  NTP.

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FPR (1)(Ferroelectric Packed-bed Reactor)
Ref. S. Futamura, H. Einaga, and A. Zhang,
Behavior of N2 and nitrogen oxides in
non-thermal plasma chemical processing of
hazardous air pollutants , IEEE transactions on
industry applications, Vol. 36, No. 6,
November/December 2000.
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FPR (2)

• Ferroelectric pellet packed-bed reactor
• Operated with a relatively small volume fraction
• of plasma that could catalytically
  activated by
• free radicals or UV irradiation from the
  plasma
• Employed an AC power supply in conjunction with a
• ferroelectric pellet layer
• Coaxial reactor
• the inner cylindrical electrode 16.6 mm
• the outer electrode 47.3 mm
• resulting in a gap distance of 15.4 mm

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FPR (3)

• The BaTiO3 pellets (?5000 at room temperature)
• 1. 1mm in diameter
• 2. packed between two electrodes with a
  high ac
• voltage applied in the radial
  direction
• 3. held by a notched perforated Teflon
  plate at
• both ends
• Effective reactor length 127 mm
• The gas passed through the entry tube (6.4mm
• in diameter) and dispersed into the plasma
  zone
• Gas flow rate 0.25 to 0.5 L/min (nitrogen)

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FPR (4)

• When an external ac voltage was applied across
  the high dielectric layer in a radial direction,
  the pellets were polarized, and an intense
  electric field was formed around each pellet
  contact point, resulting in partial discharge.
• Maximum applied voltage 50-Hz ac at up to 8-kV
  rms.

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SDR (1) (Silent Discharge Plasma Reactor)
AC power supply
Al foil
Cu-coated stainless steel electrode
Gas out
Gas in
Ref. S. Futamura, H. Einaga, and A. Zhang,
Comparsion of reactor performance in the
non-thermal plasma chemical processing of
hazardous air pollutants, IEEE transacitons on
industry applications, Vol. 37, No. 4, August
2001.
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SDR (2)

• Reactor a tubular type consisting of a stainless
  steel rod coated with copper (OD 8.6mm?) and an
  encircling glass tube (ID 10.6mm ?), which was
  wrapped with Al foil (100 mm wide)
• The effective reaction length 100 mm
• Gas flow rate 0.1 to 0.25 L/min
• Maximum applied voltage 10 kV

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Result (1)
Reactor effect on the conversions of TCE and
CH3Br in N2
Ref. S. Futamura, H. Kabashima, and H. Einaga,
Application of non-thermal plasma to chemical
reactions , IEEE transactions on industry
applications, 202nd meeting of the
electron-chemical society, Oct. 20-24, 2002.
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Result (2)
Reactor effect on H2 production from H2O and CH4
in N2
Ref. S. Futamura, H. Kabashima, and H. Einaga,
Application of non-thermal plasma to chemical
reactions , IEEE transactions on industry
applications, 202nd meeting of the
electron-chemical society, Oct. 20-24, 2002.
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Conclusion

• From result (1)
• FPR and SDR are comparable with each other
  for the decomposition of halogenated VOCs.
• From result (2)
• FPR and SDR are quite different for
  hydrogen production from water.
• Use of a pertinent reactor is important for a
  specific purpose.

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