The 13th International Workshop on Advanced Plasma Processing and Diagnostics 21-22 July 2011, Daejeon Convention Center, Daejeon, Korea

D iti f A tifi i l BiD iti f A tifi i l BiDecomposition of an Artificial BiogasDecomposition of an Artificial Biogasby a Dielectric Barrier Dischargeby a Dielectric Barrier Discharge

Kazuhiro Takahashi*, Kohki Satoh and Hidenori Itoh1Graduate School of Engineering, Muroran Institute of Technology,

Mizumoto, Muroran, 050-8585, Japan

s1724046@mmm muroran-it ac jps1724046@mmm.muroran it.ac.jp

Contents 1. Introduction -Background & Objective-

2. Experimental Apparatus & Conditions 3. Results4 C l i

MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

4. Conclusions

BackgroundBackground

Hydrogen is known as a source of clean energy, and various methodsfor hydrogen production, such as steam reforming of hydrocarbon,electrolysis of water, etc., are proposed[1].

Recently, the plasma reforming of biogas has attractedattention as a new technique to generate hydrogen.

th f t ti

Biomassdomestic animal wastes,

l d t

BiogasCH4 : 60 %CO 40 %methane fermentationsewage sludge, etc. CO2 : 40 %H2S, SO2 : ppm order

[1] J. D. Holladay et al.：Catalysis Today, 139, 244 (2004)MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

BackgroundBackground & Objective& Objective

InIn plasmaplasma reformingreforming ofof biogas,biogas, mostmost ofof researchesresearches areare intendedintended totoi ti ti ti t dd ii h dh d titi ffi iffi iinvestigateinvestigate andand improveimprove hydrogenhydrogen generationgeneration efficiencyefficiency..

However,However, byby--productsproducts fromfrom thethe biogasbiogas areare rarelyrarely investigatedinvestigated..

To investigate decomposition characteristics of an artificial biogas.

ObjectiveObjective

We generated an atmospheric dielectric barrier discharge in an artificialWe generated an atmospheric dielectric barrier discharge in an artificialbiogas, investigated by-products from the biogas, and evaluatedhydrogen generation efficiency.

MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

Experimental Apparatus & ConditionsExperimental Apparatus & Conditions

h

Applied voltageAC high voltage (15 kVp-p)

Input power : 30Wmesh

wire

path length:10mmicrosyring

path length:10m

mixture ratioCH4/CO2 = 60/40 %

IdentificationIdentification andand concentrationconcentration measurementmeasurement ofof byby--productsproductsareare carriedcarried outout byby aa GCGC--MSMS andand FTFT--IRIR..

flow rate : 0.1slmpurityCH4, CO2 : 99.5 %

yyTheThe concentrationsconcentrations ofof thethe artificialartificial biogasbiogas andand hydrogenhydrogen arearemeasuredmeasured byby aa GCGC..

4 0

Infrared absorbance spectra (without discharge)Infrared absorbance spectra (without discharge)4.0

3.5

3.0

u.]

without discharge

CHCHCOCO22

CHCH44COCO22

2.5

2.0

1 5orba

nce

[a.u CHCH44

1.5

1.0

0.5

abso

0.03500 3000 2500 2000 1500 1000 500

wavenumber [cm -1 ]

MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

Infrared absorbance spectra (with and without discharge)Infrared absorbance spectra (with and without discharge)4 04.0

3.5

3.0

u.]

without discharge with discharge

CC22HH66, , CC HH CHCH OHOH

CC22HH22

2.5

2.0

1 5orba

nce

[a.u

COCO

CC33HH88

HCHO,HCHO,CHCH33CHO,CHO,

CHCH33OH, OH, CC22HH55OHOH

CC22HH441.5

1.0

0.5

abso

CC22HH22

33 ,,(CH(CH33))22COCO CC22HH66

0.03500 3000 2500 2000 1500 1000 500

wavenumber [cm -1 ]

COCO (carbon(carbon monoxide),monoxide), CC22HH22 (acetylene),(acetylene), CC22HH44 (ethylene),(ethylene), CC22HH66 (ethane),(ethane), CC33HH88(propane),(propane), HCHOHCHO (formaldehyde),(formaldehyde), CHCH33CHOCHO (acetaldehyde),(acetaldehyde), CHCH33OHOH (methanol),(methanol),CC22HH55OHOH (ethanol)(ethanol) andand (CH(CH33))22COCO (acetone)(acetone) areare producedproduced fromfrom thethe biogasbiogas..

SinceSince thethe absorbanceabsorbance peakspeaks atat 28002800 ~~ 32003200 cmcm--11 areare saturatedsaturated duedue toto highhighconcentrationconcentration oror longlong opticaloptical pathpath length,length, thethe concentrationsconcentrations ofof thethe byby--productsproductsareare calculatedcalculated fromfrom thethe absorbance,absorbance, whichwhich dodo notnot overlapoverlap thosethose saturatedsaturated peakspeaks..a ea e ca cu atedca cu ated oo t et e abso ba ce,abso ba ce, w cw c dodo otot ove apove ap t oset ose satu atedsatu ated pea spea s..

MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

Chromatographic analysis of byChromatographic analysis of by--products (with discharge)products (with discharge)7 51.0x107

0.8

0 6a.u.

]1.0x105

0.8

0 6

TICm/z

2729

0.6

0.4

0 2inte

nsity

[a 0.6

0.4

0 2

4345

0.2

0.0

i

3.02.82.62.42.22.01.81.61.41.2retention time [min]

0.2

0.0

retention time [min]

Chromatographic analysis of byChromatographic analysis of by--products (with discharge)products (with discharge)7 51.0x107

0.8

0 6a.u.

]1.0x105

0.8

0 6

TICm/z

2729

0.6

0.4

0 2inte

nsity

[a 0.6

0.4

0 2

4345

0.2

0.0

i

3.02.82.62.42.22.01.81.61.41.2retention time [min]

0.2

0.0

1008060ns

ity [%

]

ret. time 1.275 min

retention time [min]

604020

0rela

tive

inte

n

0r

50403020100m/z [amu]

Chromatographic analysis of byChromatographic analysis of by--products (with discharge)products (with discharge)7 51.0x107

0.8

0 6a.u.

]1.0x105

0.8

0 6

TICm/z

2729

CHCH44, CO, CO22

0.6

0.4

0 2inte

nsity

[a 0.6

0.4

0 2

4345

0.2

0.0

i

3.02.82.62.42.22.01.81.61.41.2retention time [min]

0.2

0.0

1008060ns

ity [%

]

ret. time 1.275 min [ref. methane*0.546]+[ref. carbon dioxide]

retention time [min]

CC

COCO22

604020

0rela

tive

inte

n CHCH44

0r

50403020100m/z [amu]

SimilarlySimilarly wewe makemake aa searchsearch forfor referencereference massmass spectraspectra whichwhichSimilarly,Similarly, wewe makemake aa searchsearch forfor referencereference massmass spectraspectra whichwhichareare similarsimilar toto thethe massmass spectraspectra ofof eacheach peakpeak..

Chromatographic analysis of byChromatographic analysis of by--products (with discharge)products (with discharge)7 51.0x107

0.8

0 6a.u.

]1.0x105

0.8

0 6

TICm/z

2729

CHCH33CH(OH)CHCH(OH)CH33

CHCH CHOCHO

CHCH33CHCHCHCH22OO (CH(CH33))22COCO CHCH33OHOH

CHCH44, CO, CO22

0.6

0.4

0 2inte

nsity

[a 0.6

0.4

0 2

4345

HCHOHCHO

CHCH33CHOCHO CC22HH55CHOCHO (CH(CH33))22CHCHOCHCHO

CHCH22CHCHOCHCHO

CC33HH77CHOCHOCHCH33COCCOC22HH55 CC22HH55OHOH

0.2

0.0

i

3.02.82.62.42.22.01.81.61.41.2retention time [min]

0.2

0.0

CC33HH77CHOCHO

retention time [min]

HCHOHCHO (formaldehyde),(formaldehyde), CHCH33CHOCHO (acetaldehyde),(acetaldehyde), CC22HH55CHOCHO ((propionaldehydepropionaldehyde),),CC33HH77CHOCHO ((butyraldehydebutyraldehyde),), CHCH22CHCHOCHCHO ((acrylaldehydeacrylaldehyde),), (CH(CH33))22CHCHOCHCHO33 77 (( y yy y ),), 22 (( y yy y ),), (( 33))22((isobutyraldehydeisobutyraldehyde),), CHCH33CHCHCHCH22OO (propylene(propylene oxide),oxide), CHCH33OHOH (methanol),(methanol),CC22HH55OHOH (ethanol),(ethanol), CHCH33CH(OH)CHCH(OH)CH33 (isopropyl(isopropyl alcohol),alcohol), (CH(CH33))22COCO (acetone)(acetone)andand CHCH33COCCOC22HH55 (methyl(methyl ethylethyl ketoneketone)) areare producedproduced fromfrom thethe biogasbiogas..

ItIt isis likelylikely thatthat thesethese productsproducts areare limitedlimited toto onlyonly smallsmall quantities,quantities, sincesince thetheintensitiesintensities ofof thesethese productsproducts areare twotwo oror threethree ordersorders ofof magnitudemagnitude lessless thanthan thosethoseofof CHCH andand COCO

MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

ofof CHCH44 andand COCO22..

Concentrations of byConcentrations of by--productsproducts

product H2 CO C2H6 C3H8 C2H4 C2H2 others

concentration[%] 11.3 2.8 1.6 0.9 0.3 0.1 less than 0.1

HH22,, CO,CO, CC22HH66 andand CC33HH88 areare majormajor products,products, andand thethe otherother productsproducts areareminorminor productsproducts..

ItIt isis probableprobable thatthat thethe concentrationconcentration ofof byby--productproduct decreasesdecreases withwithItIt isis probableprobable thatthat thethe concentrationconcentration ofof byby productproduct decreasesdecreases withwithcarboncarbon chainchain lengthlength andand bondbond multiplicitymultiplicity..

MURORAN INSTITUTEMURORAN INSTITUTEOF TECHNOLOGYOF TECHNOLOGY

Comparison of experimental resultsComparison of experimental results

present work Zou et al.[1] Zhang et al.[2] Zhou et al.[3]

Conversion rateof CH4 [%] 25 19 63 30of CH4 [%]Conversion rateof CO2 [%] 19 19 36 22

H2 concentration [%] 11 11 38 13H2 concentration [%] 11 11 38 13

CO selectivity [%] 12 48 39 53

H2/CO ratio 4.04 1.15 1.87 0.932

H2 generation efficiency [g/kWh] 1.82 0.99 1.11 0.70

※※ For literatures, the entries in the table are the interpolated value at the mixture of CHFor literatures, the entries in the table are the interpolated value at the mixture of CH44/CO/CO22 = 60/40 %.= 60/40 %.

HH22 concentrationconcentration andand thethe conversionconversion ratesrates ofof CHCH44 andand COCO22 areare equalequal toto ororlowerlower thanthan othersothers..

pp 44 2 2

AA highhigh HH22/CO/CO ratioratio isis obtainedobtained asas aa resultresult ofof lowlow COCO selectivityselectivity..

HH22 generationgeneration efficiencyefficiency isis foundfound toto reachreach 11..8282 g/kWh,g/kWh, andand thisthis isis higherhigherthanthan othersothers..

[1] J. Zou et al.：Plasma Chemistry and Plasma Processing, 23, 1, 69 (2003) [2] Y. Zhang et al.：Fuel Processing Technology, 83, 101 (2003)[3] L. M. Zhou et al.：Energy & Fuels, 12, 6, 1191 (1998)

ConclusionsConclusions

In this work, decomposition characteristics of an artificial biogas In this work, decomposition characteristics of an artificial biogas in an atmospheric dielectric barrier discharge are investigated.in an atmospheric dielectric barrier discharge are investigated.

HH COCO CC HH CC HH CC HH CC HH HCHOHCHO CHCH CHOCHO CC HH CHOCHOHH22,, CO,CO, CC22HH22,, CC22HH44,, CC22HH66,, CC33HH88,, HCHO,HCHO, CHCH33CHO,CHO, CC22HH55CHO,CHO,CC33HH77CHO,CHO, CHCH22CHCHO,CHCHO, (CH(CH33))22CHCHO,CHCHO, CHCH33CHCHCHCH22O,O, CHCH33OH,OH,CC22HH55OH,OH, CHCH33CH(OH)CHCH(OH)CH33,, (CH(CH33))22COCO andand CHCH33COCCOC22HH55 areare producedproducedfromfrom thethe biogasbiogas inin thethe atmosphericatmospheric dielectricdielectric barrierbarrier dischargedischargefromfrom thethe biogasbiogas inin thethe atmosphericatmospheric dielectricdielectric barrierbarrier dischargedischarge..

HH22,, CO,CO, CC22HH66 andand CC33HH88 areare majormajor products,products, andand thethe otherother productsproducts areareminorminor productsproducts..

TheThe conversionconversion ratesrates ofof CHCH44 andand COCO22 comecome toto 2525 %% andand 1919 %%,,respectivelyrespectively..

hh h dh d ii ii f df d hh i li l %% ddTheThe hydrogenhydrogen concentrationconcentration isis foundfound toto reachreach approximatelyapproximately 1111 %%,, andandthisthis correspondscorresponds toto hydrogenhydrogen generationgeneration efficiencyefficiency ofof 11..8282 g/kWhg/kWh..

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