22nd International Symposium on Plasma Chemistry
July 5-10, 2015; Antwerp, Belgium
Hydrogen production from methanol treatment with gliding arc discharge
M. Pacheco-Pacheco, J. Pacheco-Sotelo, R. Valdivia Barrientos, F. Ramos-Flores, M. Duran-García, M. Hidalgo-Pérez,
H. Frias-Palos, N. Carmina and M. Garduño
Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, México
Abstract: Hydrogen is a product obtained from methanol treatment in a gliding arc
discharge between two divergent electrodes. A 0D kinetic model is proposed to understand
some basic principles of methanol transformation during plasma treatment. Results
obtained from mass spectrometry studies confirm the H 2 formation and the possibility of
CO production; both compounds are considered as very energetic gases (syngas).
Keywords: hydrogen production, methanol treatment, non-thermal plasma, syngas
0.5% to 1.7%. In Fig. 3 the influence of O• and •OH
radicals on CH 3 OH removal is reported. A 100% of
CH 3 OH removal efficiency is obtained al 1.5% water
vapour giving 200 ppm of •OH.
1020
1015
Concentration [particles/cm3]
1. Introduction
Methanol can be released to the atmosphere from
vehicles, industries (pharmaceutical, plastics sintering,
photography) and from natural sources (vegetation,
microorganisms, volcanoes). Severe signs of intoxication
with high methanol doses have been reported, they are
initially manifested by signs of narcosis, followed by
abdominal, leg and back pain, visual degeneration can
lead to blindness [1].
There are several techniques to treat methanol
compounds [2, 3], some of them can be used as biodiesel
[4]. However the interest to treat this alcohol with a
gliding arc discharge resides on the study of the H 2 and
CO synthesis and on radicals O• and •OH behaviour under
several operational conditions. These radicals are very
important in treatment of more complex compounds
(ketones,
volatile
organic
compounds
and
chlorofluorocarbons) with non-thermal plasma [5-9].
Specifically, the gliding arc plasma has a transition
region from local thermodynamic equilibrium (LTE) to a
NLTE, allowing higher electron density and higher
temperatures; therefore this kind of procedures have
greater possibilities to be applied in industry.
1010
105
10-0
10-5
10-10
0
0.001
0.002
0.003
0.004
Time [s]
0.006
0.007
0.008
0.009
0.01
0.007
0.008
0.009
0.01
Fig. 1. Formation of chemical radicals.
200
180
160
2. Chemical model and preliminary results
The proposed model takes into account the radicals
formation from the collision of energetic electrons with
molecules of vapour water and air; radicals then formed
interact to transform methanol into H 2 and CO. In
plasmas, a large number of equations occur; considering
its importance on methanol removal and syngas
production, here, in Table 1 only 29 are listed.
A mass balance is applied to chemical reactions, the
evolution of radicals and other plasma components can be
then represented in function of time. In Fig. 1 the
formation of radicals at very short time can be observed.
The concentrations of these compounds are then used to
calculate the methanol (CH 3 OH) degradation in function
of time; in Fig. 2 the CH 3 OH degradation is inferior to
45%, therefore, in order to augment the removal
efficiency water vapour concentration was increased from
P-III-9-24
Concentration [ppm]
140
120
100
80
60
40
20
0
0
0.001
0.002
0.003
0.004
Time [s]
0.006
Fig. 2. Degradation of 200 ppm of methanol, formation
of CO and H 2 .
3. Experimental Setup
The gliding arc reactor consists in three tungsten
diverging electrodes in a quartz cylinder, working at
around 90 W of power input. The methanol is added by
1
direct injection with an argon flow. A mass spectrometer
is used to identify formed compounds (Fig. 4).
2
P-III-9-24
Reaction
k
1
e − + O2 
→ O • + O • + e−
( )
k
2
e − + O2 
→ O • + O 1D + e −
k
3
→ N • + N • + e−
e − + N2 
1 x 10-8
6.5 x 10-9
2.8 x 10-13
k
4
e − + O2 
→ O2−
k
5
e − + O2 
→ O− + O •
( )
k
Rate
coefficient
cm3mol-1s-1
2 x 10-11
6
→ O2 a1∆g + e −
e − + O2 
k
7
e − + O2 
→ O2+ + 2e −
k
8
e − + N2 
→ e − + N2 ( A )
k
9
e − + CO2 
→ CO + O −
6.5 x 10-11
8 x 10-10
4.5 x 10-10
k
9 x 10-11
( )
k
O(1D ) + N2 → O • + N2
k
O(1D ) + O2 → O • + O2
k
O (1 D ) + H 2O → O • + H 2O
k
O (1D ) + O2 → O • + O2 (a1∆g )
k12
2.2 x 10-10
13
2.6 x 10-11
14
6.3 x 10-12
O D + H2O → • OH + • OH
1D
16
k
N2 (A ) + O2 17→ N2 + O • + O •
k
N2 (A ) + N2 18→ 2N2
k19
CH 3OH + O • → • CH 2 OH + • OH
k 20
CH3OH + O • →

CH3O • + • OH
k 21
CH3OH + • OH → CH3O • + H 2 O
k 22
 CH 3O + H 2 O + H •
CH 3OH + • OH →
k 23
CH 3OH + • OH 
→ • CH 2 OH + H 2 O
k 24
CH3OH + O • →

CH3O • + • OH
Argon
2.5 x 10-12
3.3 x 10-10
→ H − + OH −
e − + H2O 11
Fig. 3. Influence of radicals concentration on methanol
removal.
1.3 x 10-9
k
e − + H2O 10→ • OH + H − + e −
1
Methanol removal %
Table 1. Chemical reactions.
Mass
spectrometer
Methanol
injection
High frequency
electric source
Gliding arc
reactor
1.2 x 10-11
Fig. 4. Experimental setup.
3.4 x 10-11
The circuit supply is composed by three half bridge
inverters with a resonant circuit load constituted by
step-up transformers 1:20 for TR1, TR2 and TR3, in
series with capacitors C1 = C2 = C3 = 110nF, high
voltages can be obtained (5 kV pp ).
-12
2.5 x 10
3 x 10-16
6.77 x 10-15
5.95 x 10-14
-13
1.40 x 10
9.11 x 10-13
5.59 x 10-13
4. Experimental results and discussion
In Fig. 5, photographs of argon plasma with (b) and
without methanol (a) are displayed. A deep purple colour
is characteristic for the argon plasma, whereas for the
argon plasma with methanol a blue-green colour can be
appreciated.
4.00 x 10-11
10
k 25
• CH 2 OH + • OH → CH 2 O + H 2 O 1.50 x 10
k 26
• CH 2 OH + O • →

CH 2 O + • OH
0.40
k 27
2.51 x 10-11
k 28
1.0 x 10-11

• CH3 + O2
CH3O • + O • →
CH3O • + O • → CH 2 O + • OH
k 29

CH3O • + • OH →
CH 2 O + H 2 O
3.01 x 10-11
k 30
0.4
k 31
1.54 x10-11
• CH 3 + O • → CO + H 2 + H •
• CH3 + O • → CH3O •
Fig. 5. Plasma reactor with (a) argon plasma and (b) with
methanol.
P-III-9-24
3
A mass spectrum, representing the untreated methanol
[10], could be appreciated in Fig. 6.
Normalized intensity (a.u)
CH3O•
CH3OH
N2 isotope
CH3•
u.m.a
Fig. 6. Methanol mass spectra.
Further, in Fig. 7, the spectrum of products obtained
after methanol treatment is showed. Almost a total
removal of acetone is corroborated, as well as the H 2
production. The CO production cannot be confirmed
because it lines are overlapped with these of nitrogen.
9.4E-3
7. References
[1] Environmental
Protection
Agency. http://www.epa.gov/chemfact/s_methan.tx
t. Accessed on January 2015
[2] Y. Tao, S. Schwartz, C.Y. Wu and D.W. Mazyck.
Ind. Engng. Chem. Res., 44, 19 (2005)
[3] C.W Babbitt, A. Pacheco and A.S. Lindner.
Bioresource Technol., 100, 24 (2009)
[4] R.N Li, Z. Wang, L.C. Hou and M.D. Li. Adv. Mat.
Res., 912 (2014)
[5] A.A. Assadi, A. Bouzaza, S. Merabet and
D. Wolbert. Chem. Engng. J., 258 (2014)
[6] C. Klett, X. Duten, S. Tieng, S. Touchard, P. Jestin,
K. Hassouni and A. Vega-González. J. Hazardous
Mat., 279 (2014)
[7] M. García. Interacción arco electric, electrodos y
entorno para aplicaciones de tipo Ambiental y de
síntesis de nuevos materiales. PhD Thesis. (2013)
[8] N. Vasquez.
Estudio de la degradación de
compuestos orgánicos volátiles por arco deslizante.
Eng. Thesis. (2009)
[9] M. Garduño. Plasma trifásico deslizante. PhD
Thesis (2013)
[10] Japan AIST/NIMC Database-Spectrum MS-NW-72
Collection (C) (2014)
8.4E-3
Pressure (bar)
7.4E-3
6.4E-3
N2 or CO
5.4E-3
4.4E-3
3.4E-3
N2 isotope
2.4E-3
1.4E-3
4E-4
1
5
10
15
20 25
30
35
40
45
50
55
60
65
70
75
80
85
90
95 100
u.m.a
Fig. 7. Products obtained from plasma treatment of
methanol.
5. Conclusions
Preliminary results obtained, indicate that gliding arc
could be considered as a promissory technique to treat, in
a continuous way, methanol polluted substances at
considerably low energetic input (80 W).
The importance of •O and •OH radicals on methanol
treatment was also highlighted in the chemical model
proposed.
In order to quantify the removal efficiency a
characterization of products should be done with gas
chromatography
6. Acknowledgments
This project was supported by the ININ and CONACyT
funds. Thanks to the COMECyT and SUTIN for the
economic support granted to assist to this congress.
Many thanks to Gustavo Soria, Jesús Silva, Mario Ibañez
and Juan Salazar, for technical support.
4
P-III-9-24