[American Institute of Aeronautics and Astronautics 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit - Nashville, TN ()] 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

American Institute of Aeronautics and Astronautics

1

New Technology of Plasma Reforming of Liquid

Hydrocarbon Fuels in Dynamic Plasma-Liquid Systems

Valeriy Ya. Chernyak1, Sergei V. Olszewski

2, Vitalij V. Yukhymenko

3,

Sergei M. Sidoruk4, Oleg A. Nedybaliuk

5 and Iryna V. Prysiazhnevych

6

Faculty of Radio Physics, Taras Shevchenko Kyiv National University, Kyiv 02033 Ukraine

Anatolij I. Shchedrin7, Dmitry S. Levko

8 and Vadym V. Naumov

9

Institute of Physics, National Academy of Sciences of Ukraine, Kyiv, 03028 Ukraine

and

Valentina P. Demchina10

and Vladimir S. Kudryavzev11

Institute of Gas, National Academy of Sciences of Ukraine, Kyiv 03028 Ukraine

This paper presents the results of complex experimental and theoretical studies of the

process of nonthermal plasma-assisted reforming of ethanol-based fuels in the dynamic

plasma liquid systems using the DC and pulsed electric discharges in a gas channel with

liquid wall (DGCLW) and the DC discharge in a reverse vortex gas flow of Tornado type

with a "liquid" electrode (TORNADO-LE). In addition to the direct plasma reforming, also

pyrolysis of ethanol after initial plasma treatment was studied. The experiments

demonstrate possibilities and efficiency of low-temperature plasma-chemical conversion of

ethanol into hydrogen-rich synthesis gas in different regimes. The numerical modeling

clarifies the nature and explains the kinetic mechanisms of nonequilibrium plasma-chemical

transformations in the plasma-liquid systems in different discharge modes.

Nomenclature

Id = discharge current

U = discharge voltage

W = electric power

G = gas flow rate

T = temperature

p = pressure

I. Introduction

ODAY hydrogen (H2) is considered as one of the most perspective energy sources for the future that can be

renewable, ecologically clean and environmentally safe1. Among possible technologies for H2 production,

including steam reforming and partial oxidation of liquid hydrocarbons,2 a low-temperature plasma reforming of

1 Professor, Department of Physical Electronics, Plasma Research Lab, [email protected], AIAA Member

2 Senior Research Scientist, [email protected]

3 Junior Researcher, [email protected]

4 PhD Student

5 MS Student

6 Research Scientist, [email protected]

7 DSc, Head of Research Group, Department of Gas Electronics, [email protected]

8 PhD Student, Junior Researcher, [email protected]

9 Senior Research Scientist, [email protected], AIAA Associated Member

10 Senior Research Scientist, Gas Analysis Lab

11 Research Scientist

T

46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit25 - 28 July 2010, Nashville, TN

AIAA 2010-7063

Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

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biomass-derived ethanol (ethyl alcohol C2H5OH) is believed to be a good alternative approach.3-5

There are various

electric-discharge techniques of plasma conversion of ethanol into H2 using thermal (equilibrium) and non-thermal

(non-equilibrium) plasmas: arc, corona, spark, MW, RF, DBD, etc.6 Each plasma system has its merits and demerits,

and even difficult to compare.7 Among them, one of the most efficient is the plasma processing in the dynamic

plasma-liquid systems (PLS) using the DC and pulsed electric discharges in a gas channel with liquid wall

(DGCLW)8 and the DC discharge in a reverse vortex gas flow of Tornado type with a "liquid" electrode

(TORNADO-LE).9 Advantages of this technology are high chemical activity of plasma and selectivity of plasma-

chemical transformations, providing high-enough productivity and efficiency of conversion at a relatively low

electric power consumption on the high-voltage discharging in a flow at atmospheric pressure.10

The nonequilibrium

plasma assists as an energetic catalyst containing charged particles and electronically excited atoms and radicals,

which initiate fast chain-branching conversion of hydrocarbons that does not occur in usual conditions.11

The highly

developed plasma-liquid interface with the large surface-to-volume ratio and the deep injection of active plasma

particles into the liquid also favor to the intensification of conversion in the plasma-liquid system.12,13

At that, there

is no problem with excess heat removal since such plasma system is thermally 'cold'.14,15

The main idea is that the

discharge can burn directly in the liquid fuel without preliminary gasification.

In this paper we report new results of our experimental and theoretical studies of the process of plasma-assisted

reforming of ethanol in the PLS with the DC and pulsed DGCLW and TORNADO-LE using available methods of

diagnostics and numerical modeling.

II. Experimental

Experiments were done with the PLS reactors using the DGCLW with one (Fig. 1a) or two (Fig. 1b) gas streams

injected in the liquid. It consists of the cooper rod electrodes (1), plasma column (2), work liquid (3), electrode in

liquid (4), and quarts tubes (5). The voltage was supplied from the high power source with a ballast resistor. The

discharge channel in the liquid was formed in two modes: with a constant gas flow (G ≠ 0) and without it (G = 0).

The compressed air was served as working gas; ethanol, water and their mixture were used as working liquids.

Three different modes of discharge were studied: 1st mode, where the voltage was applied to the electrodes on

the top and bottom flanges (mode of two solid electrodes); 2nd mode, where “+” was applied to the electrode on the

bottom flange whereas “–” was applied to the liquid (“liquid” cathode, LC); and 3rd mode, where “–” was applied to

the electrode on the bottom flange whereas “+” was applied to the liquid (“liquid” anode, LA). Fig. 2 shows the

DGCLW working in the 1st mode in ethanol.

In addition to the direct plasma reforming, also pyrolysis of ethanol after initial plasma reforming was studied by

using the unit shown in Fig. 3. The installation consists of two main parts: 1) plasma reactor, which treats ethanol-

water mixture in the pulsed DGCLW, and 2) pyrolytic reactor, which treats ethanol-air vapors mixed with products

generated by plasma reactor, where (1) is the Teflon insulator around the steel pins, (2) are steel pins through which

voltage is applied, (3) are copper electrodes, conical bottom and top cylinder, (4) is a discharge plasma zone

between electrodes, (5) is a vortex zone in the discharge, (6) is a bubbling zone in the liquid, (7) is the work liquid

(solution of 96% pure ethanol and distilled water), (8) are mixing inlet and outlet chambers, (9) is the steel pyrolytic

chamber; (10) are electric heaters, (11) is the cylindrical casing; (12) are thermocouples for temperature control, (13)

is the glass vessel (0.5 l) for the output syngas collection.

3

1 5

5 Air

2

4 4

3

1 5

5 Air Air

Air Air

2

(a) ( b)

Figure 1. Schematic of the plasma-assisted reforming of ethanol

in the electric discharge in a gas channel with liquid wall.

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Another PLS reactor used with the discharge TORNADO-LE is shown in Fig. 4. It consists of a cylindrical

quartz vessel (1) with diameter of 9 cm and height of 5 cm, sealed by the flanges at the top (2) and at the bottom 3.

The vessel was fueled by the work liquid (4) via the inlet pipe (5); the level of liquid was controlled by the spray

pump. The basic water-cooled T-shaped 2.5 cm-diameter cylindrical electrode (6) on the bottom flange (3) made

from stainless steel was fully immersed in the liquid. The second electrode on the top flange (2) made from

duralumin had the copper hub (11) with the axial nozzle (7) of 2 mm inner diameter and 6 mm length. The gas was

fed into the reactor chamber through the orifice (8) in the top flange (2) tangentially to the wall (1) and formed a

vortex flow of tornado type, so the swirling gas (9) went down to the liquid surface and moved to the center of the

system, where it flowed out through the nozzle (7) in the form of jet (10) into the quartz chamber (12). Since the

area of minimal static pressure above the liquid surface during the vortex gas flow was located near the central axis,

it created the column of liquid at the gas-liquid interface in the form of the cone of ~1 cm height above the liquid

surface as is shown in Fig. 4.

Figure 2. Photo of the DC DGCLW working at air flow in ethanol.

LA= 60 mm,

dA=15 mm

Air 1

2

8 9 10 11

1

3

A B

dB = 6 mm

7

Liquid

Air

2

3

4

5

6

1

Syngas

Figure 3. Schematic of the ethanol pyrolysis after initial plasma reforming

of ethanol in the pulsed DGCLW.

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The plasma torch (10) of ~5 cm long was formed during the discharge in the chamber. The voltage was applied

between the top flange (2) and the electrode (6) in the liquid (4) from the DC source powered up to 10 kV. In

experiments, two basic modes of discharge were studied: 1) with “liquid” cathode (LC), and 2) with “liquid” anode

(LA), using “+” on the flange (2) in the LC mode, and “-” on the flange (2) in the LA mode. The conditions of

breakdown were regulated by three parameters: by the level of working liquid; by the gas flow rate G; and by the

applied voltage U. The discharge ignition began with the appearance of axial streamer. Time for establishing a self-

sustained discharge burning was ~1-2 s after the first streamer. The discharge current varied within the range 100-

400 mA. The pressure in the discharge chamber during the discharge was ~1.2 atm, the static pressure outside the

reactor was ~1 atm. Fig. 5 shows the TORNADO-LE working in the ethanol-water solution.

Figure 4. Schematic of the PLS reactor with the DC discharge in

a reverse vortex flow of TORNADO type with a liquid electrode.

Figure 5. Photo of the DC TORNADO-LE

working in the ethanol-water mixture.

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III. Diagnostics

Diagnostics of parameters of discharge plasma in the PLS was carried out using optical emission spectroscopy

(OES) and absorption spectroscopy (OAS) methods. A portable high-speed CCD-based spectrometer “Plasma-spec”

with a spectral resolution 0.6 nm was used for recording spectra in the wavelength range 200-1100 nm. The standard

deuterium and tungsten band lamps were used as light sources for measuring absorption spectra of plasma-treated

liquids and for spectral calibration of emission spectra of discharge plasma.16

Characteristic temperatures corresponding to excited states of atoms (electronic temperature Te*) and molecules

(vibrational Tv* and rotational Tr

* temperatures) in discharge plasma were determined by different OES methods.

The electronic temperature Te* was determined by relative intensities of emission of atomic hydrogen lines (H

656.3 nm, H 486.1 nm) and oxygen multiplet lines (OI 777.2; 844.6; 926.6 nm). To determine vibrational Tv* and

rotational Tr* temperatures, the original technique of spectra processing with using the SPAN

17 and SPECAIR

18

simulation of spectral radiation of molecular bands: N2 2+-system (C

3u-B

3g), OH UV-system (A

2 +-X

2П), and

CN Violet-system (B2 +

-X2 +

) was developed and applied.19

Diagnostics by mass-spectrometry with using a monopole mass-spectrometer МX-7301 and by gas-phase

chromatography with using a gas chromatograph 6890N Agilent with a set of thermoconductive detectors was

carried out to analyze and monitor syngas products after the ethanol processing in the PLS as usual procedure.15

IV. Numerical Model

The physical model of the DGCLW in the PLS was based at the next assumptions20

:

i) electric power that introduced in the discharge, is rapidly averaged over the discharge volume;

ii) electric field in the discharge is uniform and does not vary in time and space;

iii) during the passage of discharge products from the discharge to the reactor the gas composition in the cavity is

fully refreshed, and gas flow rate in the reactor is the same as in the discharge.

The mathematical modeling of the process in the DGCLW-PLS was based on the next features21

:

1) calculation of the electron energy distribution function by solving the Boltzmann kinetic equation;

2) hydrodynamic modeling in quasi-1D volume averaged approximation;

3) plasmachemical kinetic modeling by solving the system of kinetic equations for all kinetically valuable

components of the air-ethanol-water plasma-chemical system. The full kinetic mechanism included 65 species

(C2H5OH, N2, O2, H2O, H2, CO, etc.), 92 electron-molecular processes and 446 chemical reactions with a set of

corresponding cross-sections and rate constants, compiled according to update recommendations of the NASA and

NIST databases (details are available at A. I. Shchedrin's Group Web-site).22

V. Results and discussion

The typical current-voltage characteristics of the DC DGCLW working in ethanol at different discharge modes

are shown in Fig. 6. The data are given for the case of mixture C2H5OH : H2O = 5:1 and air flow rate G = 55 cm3/s.

A dropping character of I-V curves at discharge currents from 100 to 400 mA indicates the transition regime from

the abnormal glow to the arc discharge.

0

1

2

3

4

0 100 200 300 400 500

I, mA

U, kV liquid "-"

liquid "+"

solid electrodes

Figure 6. Current-voltage characteristics of the DC DGCLW

working in ethanol at different discharge modes.

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The typical voltage and current oscillograms for the pulsed DGCLW are shown in Fig. 7.

The typical current-voltage characteristics of the DC discharge TORNADO-LE in the mode with a liquid anode

working in water at different air flow rates from 0 to 110 cm3/s are shown in Fig. 8.

The results of mass-spectroscopic and gas-chromatographic measurements of concentrations of H2 and other

components in the syngas products after the ethanol reforming in the DGCLW at different currents Id = 100-400 mA

and air flow rates G = 0-110 cm3/s are shown in Figs. 9-10. The data are given for the discharge mode with solid

electrodes and for the case of mixture C2H5OH : H2O = 5:1. One can see a good matching between gas-

chromatography and mass-spectrometry data.

It should be noted that with increasing air flow rate in the discharge the relative content of H2 in syngas products

decreases. In fact, the highest yield of H2 is observed in the discharge mode without air supply (point G = 0 in

Fig. 10). However, the time of H2 production in this case increases considerably, and the electric power consumption

also increases. Therefore, the total system performance without air supply seems to be not very promising.

-2000

-1000

0

1000

2000

0 0.000002 0.000004 0.000006

t, s

U, V

-300

-200

-100

0

100

200

300U

I

Figure 7. Voltage and current oscillograms in the

pulsed DGCLW.

Figure 8. Current-voltage characteristics of the TORNADO-LE

with a liquid anode working in water at different air flow rates.

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The results of mass-spectrometry of syngas products after the ethanol reforming in the TORNADO-LE with a

liquid cathode are shown in Fig. 11. The data are given for the case of mixture C2H5OH : H2O = 5:1, air flow rate

G = 55 cm3/s, voltage U = 2 kV and current Id = 320 mA. One can see that the content of H2 and CO in output

syngas products is quite high.

0

0,2

0,4

0,6

0,8

1

1,2

0 100 200 300 400

I, mA

I, a.u.

Gas chrom.

Mass spect.

H2

Figure 9. Content of H2 in output syngas products measured by gas

chromatography and mass-spectrometry after the ethanol reforming

in the DGCLW at different discharge currents Id. Discharge mode

with solid electrodes, air flow rate G = 55 cm3/s

Figure 10. Concentrations of components of syngas products after the ethanol

reforming in the DGCLW with solid electrodes at different air flow rates G.

Discharge current Id = 100 mA.

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The results of the studies of the post-discharge pyrolysis of ethanol after initial plasma-assisted reforming in the

pulsed DGCLW are presented in Figs. 12. It shows the H2 content in syngas products measured after the ethanol

pyrolysis in the pyrolytic chamber. The experimental parameters were following: discharge frequency of 420 Hz, air

flow rate G = 17-28 cm3/s, time of treatment up to 10 min, temperature in the pyrolytic chamber varied from 0 to

870 K. It was found a good correlation between mass-spectrometry and gas-chromatography data. On the whole, H2

production with discharge is higher than without discharge; it is especially noticeable at low temperatures.

The results of calculations of concentrations of H2, CO2 and other main stable components in output syngas

products after the ethanol reforming in the PLS with the DC DGCLW are shown in Fig. 13 (a, b). The qualitative and

quantitative agreement between calculated and measured data is quite good, at least, for the main syngas components.

One can see that the output concentration of H2 grows almost linearly with the discharge current and it reduces

exponentially with the air flow rate.

Figure 11. The component content of syngas products after the ethanol reforming

in the TORNADO-LE with a liquid cathode.

0

0.5

1

1.5

2

2.5

3

0 150 300 450 600

T, C

H2, a.u.

D+P

P

Figure 12. Content of H2 in syngas products after the ethanol pyrolysis

vs. temperature in the pyrolitic chamber. P is pyrolysis with discharge off;

D+P is pyrolysis with discharge on.

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In the considered discharge conditions, the kinetics of H2 formation is determined mainly by reaction C2H5OH+H

→ CH3CH2O+H2. As the concentration [C2H5OH] in solution changes slowly, the [H2] production is determined

entirely by concentration of H. In the case under consideration, the main process responsible for the generation of H is

the dissociation of H2O by the direct electron impact. The rate of this process is proportional to the specific electric

power deposited to discharge, i.e., to discharge current. Therefore, the [H2] production is also a linear function of the

discharge current in accordance with experimental data. Outside the discharge, the only process that influences the H2

concentration is the water-gas shift (WGS) reaction CO + H2O → H2 + CO2. Via this process, the system reaches the

complete conversion of CO into CO2 and H2.

The estimation of efficiency of the plasma-assisted reforming of ethanol into the hydrogen-rich syngas in the

studied PLS with the DGCLW was performed on the basis of thermochemical calculations using criteria: (a) energy

cost of 1 m3 syngas products; (b) productivity of conversion; (c) specific heat of 1 m

3 syngas combustion, and (d)

energy efficiency. Calculations were made with taking into account standard thermochemical constants of

hydrocarbons23

using the formula for the coefficient of energy transformation:8

IPE

YLHVY i

i

i )(

(1)

and also for the conversion efficiency by Fulcheri et al.7:

)(

)()( 22

HCLHVYIPE

HLHVYY

HC

COH (2)

Here, IPE is the input plasma energy, Y is the molar fraction, LHV is the lower heat value of species, HC is the

hydrocarbon fuel (ethanol). The formula (2) assumes that CO can be totally transformed into H2 via WGS reaction

with zero energy cost.

The results of estimations in the form of and dependencies for the ethanol reforming in the DC DGCLW as a

function of the discharge power for different discharge modes are presented in Fig. 14 (a, b). The data are given for

the case of mixture C2H5OH : H2O = 5:1. One can see that the coefficient has the same growth trend with

increasing current as the H2 yield. At that, each mode demonstrates increased efficiency with increasing current.

Figure 13. Concentrations of H2 and other components of syngas products after the ethanol reforming in the

DGCLW at different air flow rates (left) at Id = 100 mA and at different currents (right) at G= 55 cm3/s.

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We obtained in the DGCLW in the mode with solid electrodes at Id = 300 mA the net H2 yield is ~15% whereas

the energy efficiency of the ethanol conversion into the syngas is up to 55%. The electric power consumption lies

between 2.4 and 3 kWh/Nm3. These numbers correlate with our earlier data

24,25 and are comparable with results

from other known plasma-aided ethanol reforming systems reported by Fulcheri et al.7

Fig. 15 shows the coefficient of energy transformation α at the combined (discharge + pyrolysis) reforming of

ethanol as a function of temperature in the pyrolytic chamber. It is seen that value α increases with increasing

temperature. Some regimes with the changing air flow (modes 5+2 and 5+3 correspond to additional air supply into

the pyrolytic chamber comparably with the air supply in the discharge) have lower efficiency than the mode with the

constant air flow because of variation of partial output of isobutane iC4H10. One can conclude that the combination

of discharge and pyrolysis for the fuel reforming demonstrates the smart efficiency of this synergetic approach.

The dependence of the coefficient of energy transformation α for the ethanol reforming in the PLS with the

TORNADO-LE as a function of the initial ethanol concentration in the ethanol-water mixture is presented in Fig. 16.

It demonstrates rather high efficiency of the fuel reforming.

0

10

20

30

40

50

60

0 200 400 600 800

P, W

, %

liquid "-"

liquid "+"

solid

electrodesЛинейный

(liquid "+")

0

0.4

0.8

1.2

1.6

2

0 200 400 600 800

P, W

liquid "-"

liquid "+"

solid electrodes

Figure 14. Efficiency of conversion (left) and coefficient of energy transformation (right) for the ethanol

reforming in the DGCLW in different discharge modes as a function of the discharge power

(discharge currents are from 50 to 400 mA).

0

2

4

6

8

10

0 200 400 600 T, °C

, a.u. ethanol-3.9 cm3/min air-28 cm3/s (5.2:(1+0))

ethanol-3.9 cm3/min air-39 cm3/s (5.2:(1+0.4))

ethanol-3.9 cm3/min air-45cm3/s (5.2:(1+0.6))

Figure 15. Coefficient of energy transformation at the combined pyrolisis

of ethanol vs. temperature in the pyrolytic chamber.

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VI. Conclusion

In summary, our investigations have shown the following.

The dynamic plasma-liquid systems with the DC and pulsed discharges in a gas channel with liquid wall and the

DC discharge in a reverse vortex gas flow of Tornado type with a "liquid" electrode are quite efficient in low-

temperature plasma-assisted reforming of ethanol into syngas comparable to other known electric-discharge

systems of atmospheric pressure such as diaphragm and arc discharges.

According to optical spectrometry, the investigated discharges are characterized by high degree of

nonequilibrium and nonisothermality. Reactive plasma contains a lot of excited atoms and radicals (H, O, OH,

etc.) associated with dissociation of molecules in ethanol-water vapors, thus providing desirable selectivity and

productivity of plasma-chemical fuel conversion.

According to mass-spectrometry and gas-phase chromatography, the main components of syngas produced from

ethanol in the plasma-liquid reactor are molecular hydrogen H2 and carbon oxides CO and CO2, which relative

fraction reaches 90%, i.e. many times higher than other hydrocarbons CH4, C2H2, C2H4, and C2H6.

The composition content of output syngas products and the electric power inputs on the ethanol conversion

depends on the gas that forms the plasma in the discharge and on the ethanol-water ratio in the mixture. At that,

the relative concentration of H2 grows with the discharge power linearly up to the saturation.

The polarity of electrodes in the case of ethanol does not influence the H2 production; however, in the case of

water the relative yield of H2 is higher in the mode with a liquid anode due to effect of electrolysis.

The maximal absolute yield of H2 ~15% was obtained when ethanol and water in the mixture taken in equal

amounts. In that case the efficiency of the ethanol conversion reaches ~50%.

The minimal value of the electric power consumption on the ethanol conversion in the studied regimes is about

2.4 kWh/m3 at the heat capacity of the output syngas ~4.4 kWh/m

3.

The use of pyrolysis of ethanol in the pyrolitic chamber combined with the plasma-assisted reforming provides a

synergetic effect of increasing the overall efficiency of conversion compared with only plasma-liquid systems.

The kinetic plasma-chemical modeling is in a fairly good agreement with experimental data, at least, for the

main syngas components, H2, CO, and CO2, thus explaining nonequilibrium character of the non-thermal

plasma-chemical mechanism of the ethanol conversion in the studied plasma-liquid systems.

Acknowledgments

This work was supported in part by the U.S. European Office of Aerospace Research & Development, by the

Science & Technology Center in Ukraine, by the Ministry of Science & Education of Ukraine and by the National

Academy of Sciences of Ukraine. Authors thank Dr. Julian M. Tishkoff from the U.S. Air Force Office of Scientific

Research for helpful discussions and advices in research.

Figure 16. Coefficient of energy transformation

for the ethanol reforming in the TORNADO-LE

as a function of initial ethanol concentration.

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Non-Thermal Arc Discharge,” Energy & Fuels, Vol. 24, No. 4, 2010, pp. 2607-2613. 4Demіnsky, M., Jіvotov, V., Potapkіn, B., and Rusanov, V., “Plasma-Assisted Production of Hydrogen from Hydrocarbons,”

Pure Appl. Chem., Vol. 74, No. 3, 2002, pp. 413-418. 5Bromberg, L., Cohn, D. R., Rabinovich, A., Hadidi, K., Alexeev, N., and Samokhin, A., “Plasma Catalytic Reforming of

Bio fuels,” MIT Plasma Sci. Fusion Center Rept. PSFC/JA-03-28, Dec. 2003. [Online] URL: http://www.psfc.mit.edu 6Fridman, A., Plasma Chemistry, Cambridge University Press. New York, 2008. 7Petitpas, G., Rollier, J.-D., Darmon, A., Gonzalez-Aguilar, J., Metkemeijer, R., and Fulcheri L., “A Comparative Study of

Non-Thermal Plasma Assisted Reforming Technologies,” Int. J. Hydrogen Energy, Vol. 32, No. 14, 2007, pp. 2848-2867. 8Chernyak, V. Ya., Olszewski, S. V., Yukhymenko, V. V., Solomenko, E. V., Prysiazhnevych, I. V., Naumov, V. V., Levko,

D. S., Shchedrin, A. I., Ryabtsev, A. V., Demchina, V. P., Kudryavtsev, V. S., Martysh, E. V., and Verovchuck, M. A., “Plasma-

Assisted Reforming of Ethanol in Dynamic Plasma-Liquid System: Experiments and Modeling,” IEEE Trans. Plasma Sci., Vol.

36, No. 6, Dec. 2008, pp. 2933-2939. 9Nedybaliuk, O. A., Olszewski,. S. V., Chernyak V. Ya., and O. I. Lomonos, “Discharge in Reverse Vortex Flow of Tornado

Type,” Proc. V Int. Conf. "Electronics and Applied Physics", 23-25 Oct. 2009, Kyiv, Ukraine, Taras Shevchenko Nat. Univ. of

Kyiv, 2009, pp. 142-143. 10Prysyazhnevych, I., Chernyak, V., Skalny, J. D., Matejcik, S., Yukhymenko, V., Olszewsky, S., and Naumov, V., “Sources

of Nonequilibrium Plasma at Atmospheric Pressure,” Ukr. J. Phys., Vol. 53, No. 5, 2008, pp. 472-476. 11Yukhymenko, V. V., Chernyak, V. Ya., Olshevskii, S. V., Prisyazhnevich, I. V., Zrazhevskii, V. A., Verovchuk, M. O.,

Solomenko, O. V., Skalny, J. D., Matejcik, S., Demchina, V. P., Kudryavtsev, V. S., and Naumov, V. V., “Plasma Conversion of

Ethanol-Water Mixture to Synthesis Gas,” Ukr. J. Phys., Vol. 53, No. 5, 2008, pp. 409-413. 12Veremii, Yu. P., Chernyak, V. Ya., Trokhymchuk, A. K., Kondratyuk, Ya. V., and Zrazhevskij, V. A., “Physicochemical

Properties of a Plasma-Liquid System with an Electric Discharge in a Gas Channel with a Liquid Wall,” Ukr. J. Phys., Vol. 51,

No. 8, 2006, pp. 769-774. 13Veremii, Yu. P., Chernyak, V. Ya., Naumov, V. V., Yukhymenko, V. V., and Dudko, N. V., “Optical Properties and Some

Applications of Plasma-Liquid System with Discharge in the Gas Channel with Liquid Wall,” Problems Atom. Sci. Technol., Ser.

Plasma Physics, Vol. 12, No. 6, 2006, pp. 216-218. 14Yukhymenko, V. V., Chernyak, V. Ya., Naumov, V. V., Veremii, Yu. P., and Zrazhevskij, V. A., “Combustion of Ethanol

Air Mixture Supported by Transverse Arc Plasma,” Problems Atom. Sci. Technol., Ser. Plasma Physics, Vol. 13, No. 1, 2007, pp.

142-144. 15Chernyak, V. Ya., Yukhymenko, V. V., and Slyusarenko, Y. I., “Conversion of Ethanol in Plasma of the Gas Discharge

with Liquid Walls,” Bull. Univ. of Kyiv, Ser. Phys. & Math., No. 1, 2007, pp. 292-295. 16Yukhymenko, V. V., Chernyak, V. Ya., Naumov, V. V., Prysiazhnevych, I. V., Skalny, J. D., Matejcik, S., and Sabo, M.

“Optical Researches of Discharge Plasma in Air Channel with Water Wall,” Bull. Univ. of Kyiv, Ser. Phys. & Math., No. 4, 2006,

pp. 346-353. 17Spectrum Analyzer. [Online] URL: http://www.physics.muni.cz/~zdenek/span; Navratil, Z., Trunek, D., Smid, R., Lazar,

L., “A Software for Optical Emission Spectroscopy – Problem Formulation and Application to Plasma Diagnostics,”

Czechoslovak J. Phys., Vol. 56, Suppl. B, 2006, pp. 944-951. 18SPECAIR. [Online] URL: http://www.specair-radiation.net; Laux, C. O., Spence, T. G., Kruger, C. H., and Zare, R. N.,

“Optical Diagnostics of Atmospheric Pressure Air Plasma,” Plasma Sources Sci. Technol., Vol. 12, No. 2, 2003, pp. 125-138. 19Prysiazhnevych, I., Chernyak, V., Olzewskii, S., and Solomenko, O., “Technique of Determining of Vibrational-Rotational

Excitation Temperatures of Molecules in Gas Discharge Atmospheric Pressure Plasmas,” Ukr. J. Phys., 2010 (to be published). 20Shchedrin, A. I., Levko, D. S., Chernyak, V. Ya., Yukhymenko, V. V., and Naumov, V. V., “Effect of Air on the

Concentration of Molecular Hydrogen in the Conversion of Ethanol by a Nonequilibrium Gas-Discharge Plasma,” JETP Lett.,

Vol. 88, No. 2, 2008, pp. 99-102. 21Shchedrin, A. I., Levko, D. S., Ryabtsev, A. V., Chernyak, V. Ya., Yukhymenko, V. V., Ol'shevskiy, S. V., Prisyazhnevich,

I. V., Solomenko, E. V., Naumov, V. V., Demchina, V. P., and Kudryavtsev, V. S., “Plasma's Kinetics in Discharge in Mixture of

Air, Water and Ethanol Steams and the Questions of Alternative Fuel,” Problems Atom. Sci. Technol., Ser. Plasma Electronics,

Vol. 6, No. 4, 2008, pp. 159-162. 22Shchedrin's Group Web site. [Online] URL: http://www.iop.kiev.ua/~plasmachemgroup 23NIST Standard References Databases. [Online] URL: http://www.nist.gov/srd/ 24Chernyak, V. Ya., Yukhymenko, V. V., Solomenko, E. V., Slyusarenko, S. V., Olzhevskij, S. V., Prisyzhnevich, I. V.,

Martysh, E. V., Naumov, V. V., Demchina, V. P., and Kudryavzev, V. S., “Plasma Production of Hydrogen-Enriched Gases from

Ethanol,” Proc. 3rd Int. Workshop & Exhibit. on Plasma Assisted Combust., 18-21 Sept. 2007, Falls Church, Virginia, ed. by I.

Matveev, APT, McLean, 2007, pp. 33-36. 25Chernyak, V. Ya., Olzhevskij, S. V., Yukhymenko, V. V., Prisyzhnevich, I. V., Verovchuk, M. A., Solomenko, E. V.,

Zrazhevskij, V. A., Naumov, V. V., Shchedrin, A. I., Levko, D. S., Demchina, V. P., and Kudryavzev, V. S., “Study of Plasma

Conversion of Ethanol into Syngas in Dynamic Plasma-Liquid Systems,” Proc. 4th Int. Workshop & Exhibit. on Plasma Assisted

Combust., 16-19 Sept. 2008, Falls Church, Virginia, ed. by I. Matveev, APT, McLean, 2008, pp. 68-70.

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