Synergistic Decomposition of CO2 by Hybridization of a Dielectric Barrier Discharge Reactor and a Solid Oxide Electrolyser Cell

Self Cite

Hybrid reactor of Dielectric Barrier Discharge (DBD) and Solid Oxide Electrolyser Cell (SOEC) was fabricated and CO2 decomposition characteristics were investigated. For the case of the DBD reactor alone, the CO2 conversion saturates with residence time. In contrast, the saturation is not observed for the case of the hybrid system where CO2 conversion increases monotonically with increasing residence time. This is because the reverse reaction to regenerate the CO2 in plasma is suppressed by the oxygen removal by SOEC in hybrid system and consequently CO2 decomposition reaction proceeds irreversibly. We have examined the experimental results by analytical modeling and reaction mechanism for the CO2 decomposition in the hybrid reactor of DBD and SOEC is deduced. The time‐dependent CO2 conversion for the only plasma reactor and hybrid reactor can be reproduced by a reversible and irreversible first‐order reaction model, respectively. The analytical model can also reproduce the dependence of CO2 conversion on the plasma input power very well. Interestingly, not only the reverse reaction rate but also the forward dissociation reaction rate is reduced by the SOEC in the case of hybrid reactor. The analytical modeling suggests that CO2 decomposition in the conventional DBD plasma reactor proceeds not merely by direct electron impact dissociation but also by reaction with reactive oxygen.

Section: Resultsmentioning

confidence: 80%

Synergistic CO₂ conversion by hybridization of dielectric barrier discharge and solid oxide electrolyser cell

Mori

Tun

2016

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“…Finally, this idea also has some potential for enhancing the CO 2 conversion according to Le Chatelier's law, by removing the O 2 from the plasma, which has already been demonstrated in literature for a hybrid DBD reactor with a solid oxide electrolyser cell …”

Section: Resultsmentioning

confidence: 82%

Plasma based CO₂ and CH₄ conversion: A modeling perspective

Bogaerts

Bie

Snoeckx

et al. 2016

This paper gives an overview of our plasma chemistry modeling for CO 2 and CH 4 conversion in a dielectric barrier discharge (DBD) and microwave (MW) plasma. We focus on pure CO 2 splitting and pure CH 4 reforming, as well as mixtures of CO 2 /CH 4 , CH 4 /O 2 , and CO 2 /H 2 O. We show calculation results for the conversion, energy efficiency, and product formation, in comparison with experiments where possible. We also present the underlying chemical reaction pathways, to explain the observed trends. For pure CO 2 , a comparison is made between a DBD and MW plasma, illustrating that the higher energy efficiency of the latter is attributed to the more important role of the vibrational levels. K E Y W O R D S0D chemical kinetics model, CO 2 and CH 4 conversion, dielectric barrier discharges, microwave plasmas, plasma chemistry modeling | INTRODUCTIONIn recent years, there is increasing interest in plasma used for CO 2 and CH 4 conversion. Several types of plasma reactors are being investigated for this purpose, including (packed bed) dielectric barrier discharges (DBDs), [1][2][3][4][5][6][7][8][9][10][11][12][13][14] microwave (MW) plasmas, [15][16][17][18][19][20] ns-pulsed, [21] spark, [22][23][24] and gliding arc (GA) [25][26][27][28][29][30][31][32] discharges. Research focuses on pure CO 2 splitting into CO and O 2 , on CH 4 (and other hydrocarbons) reforming, and on mixtures of CO 2 with a hydrogen-source, that is, mainly CH 4 , but sometimes also H 2 O or H 2 , to produce value-added chemicals like syngas, hydrocarbons, and oxygenated products. Key performance indicators are the conversion and the energy efficiency of the process, as well as the possibility to produce specific value-added chemicals with good yields and selectivity. To realize the latter, the plasma should be combined with a catalyst (e.g., [3][4][5][6][7][8][9]33,34] ), as the plasma itself is a too reactive environment, and thus produces a wealth of reactive species, which easily recombine to form new molecules, without any selectivity.To improve the conversion, product yields and energy efficiency of this process, a good insight in the underlying plasma chemistry is crucial. This can be obtained by experiments, but measuring the reactive species densities inside the plasma is far from evident. Therefore, modeling of the plasma chemistry can be a valuable alternative, as it provides information on the most important chemical reaction pathways, and how to tune them to improve the conversion, energy efficiency, and product formation.In the 80s and 90s, some papers have been published on CO 2 plasma chemistry modeling, with applications to CO 2 lasers. [35][36][37] These models, however, did not consider the vibrational kinetics, which are important for energy efficient CO 2 conversion. [38] Some other papers have described the vibrational kinetics for gas flow applications, [39,40] but without focusing on the plasma chemistry. In 1981 Rusanov

“…[2] Recently, researchers from the Tokyo Institute of Technology explored a hybrid reactor, integrating a dielectric barrier discharge (DBD) plasma reactor and a solid oxide electrolysis cells (SOEC's). [25] CO 2 conversion was significantly enhanced in the hybrid reactor. Complete CO 2 conversion was found at a temperature as low as 600°C.…”

Section: Discussionmentioning

confidence: 92%

Plasma‐driven dissociation of CO₂ for fuel synthesis

Bongers

Bouwmeester

Wolf

et al. 2016

181

238

Power‐to‐gas is a storage technology aiming to convert surplus electricity from renewable energy sources like wind and solar power into gaseous fuels compatible with the current network infrastructure. Results of CO2 dissociation in a vortex‐stabilized microwave plasma reactor are presented. The microwave field, residence time, quenching, and vortex configuration were varied to investigate their influence on energy‐ and conversion efficiency of CO2 dissociation. Significant deterioration of the energy efficiency is observed at forward vortex plasmas upon increasing pressure in the range of 100 mbar towards atmospheric pressure, which is mitigated by using a reverse vortex flow configuration of the plasma reactor. Data from optical emission shows that under all conditions covered by the experiments the gas temperature is in excess of 4000 K, suggesting a predominant thermal dissociation. Different strategies are proposed to enhance energy and conversion efficiencies of plasma‐driven dissociation of CO2.