Enhancement of CO2 conversion in microwave plasmas using a nozzle in the effluent

Hecimovic, A.; D'Isa, F.; Carbone, E.; Fantz, U.

doi:10.1016/j.jcou.2021.101870

Cited by 36 publications

(36 citation statements)

References 20 publications

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“…[83] This reaction pathway thus requires a high collisional plasma (pressure higher than ~100 mbar) at limited SEI, that is, adjusted residence time, however, recombination and back reactions should be avoided. [84][85][86] Low-pressure plasma conditions using RF excitation, on the contrary, generally do not support gas phase reactions among heavy species, thus promoting electron impact dissociation, also involving vibrationally excited intermediates. Only a few studies have thus been conducted using low pressure (and low temperature) RF plasmas for CO 2 conversion.…”

Section: Plasma Gas Conversionmentioning

confidence: 99%

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Plasma activation mechanisms governed by specific energy input: Potential and perspectives

Hegemann

2023

Plasma Processes & Polymers

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In a low‐temperature plasma, the electrons pick up energy from the electric field in collisions with atoms and molecules, gaining high kinetic energy that must be sufficient for ionizing reactions to sustain the plasma. For molecular gases, an average energy per heavy gas particle is thus available in the plasma, the specific energy input, yielding plasma activation by inelastic collisions. Following a distribution law, the probability for the activation mechanism can be described by an Arrhenius‐like equation. The potential of this approach is demonstrated on the basis of plasma polymerization and plasma CO2 conversion. For perspective, energy efficiencies are discussed as a function of conversion indicating the optimum that can be achieved by electron impact activation compared with additional ways of energy transfer, probably depending on certain constraints.

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Section: Plasma Gas Conversionmentioning

confidence: 99%

Section: Applicability Of the Arrhenius‐like Approachmentioning

confidence: 99%

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

Hegemann

2023

Plasma Processes & Polymers

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“…The basic concept of such a MW plasma torch is described in Leins et al, 23 and it has been studied for the conversion of CO 2 in various works, with and without obstructions in the effluent. 8,9,24,25 A water-cooled, 5 mm wide stainless steel nozzle was employed on top of the quartz tube for the following three reasons. First, the nozzle forces the mixing of the hot gas coming from the plasma (6000 K in the core) with the surrounding colder gas, enabling fast cooling rates and improved performances at quasi-atmospheric pressure.…”

Section: ■ Experimental Setup and Proceduresmentioning

confidence: 99%

“…Conversions and energy efficiencies above 20% for CO 2 flows of 7000 sccm (standard cm 3 per minute, at 273.15 K and 1.013 bar) have been achieved. 8 These conditions correspond to a total amount of ≃700− 900 sccm O 2 available to be extracted. Second, for CO 2 flows of 7000 sccm, this nozzle yields rather high temperatures (≥700 °C) and homogeneous temperature profiles in the effluent as shown below.…”

Section: ■ Experimental Setup and Proceduresmentioning

confidence: 99%

“…2,3 Microwave (MW) and gliding arc plasmas have yielded the highest performances so far. 2,3 Among the strategies pursued to increase the efficiency of CO 2 splitting close to atmospheric pressure is the fast cooling of the converted gas to prevent backward reactions, e.g., CO + O + M → CO 2 + M. 4−6 This has been demonstrated either by employing water-cooled nozzles 7,8 or water-cooled channels 9 on top of the plasma generated by a MW plasma torch. The outlet gas mixture of plasma-based conversion technology consists typically of CO 2 , CO, and O 2 , which contrasts with the O 2 -free streams produced by electrolysis cells.…”

Section: ■ Introductionmentioning

confidence: 99%

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Proof of Concept for O₂ Removal with Multiple LCCF Membranes Accommodated in the Effluent of a CO₂ Plasma Torch

Antunes,

Wiegers,

Hecimovic

et al. 2023

ACS Sustainable Chem. Eng.

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The removal of oxygen from the effluent of a CO 2 plasma using multiple perovskite La 0.6 Ca 0.4 Co 0.5 Fe 0.5 O 3−δ hollow fiber membranes is reported. A microwave plasma torch featuring a water-cooled 5 mm nozzle operated at quasi-atmospheric pressure was used. This configuration yielded moderate CO 2 conversions (≥20%) and sufficiently large temperatures to thermally activate up to 21 membranes distributed over various rows in the plasma effluent. The CO 2 conversion was only slightly affected by the microwave power and remained unchanged, regardless of the number of membranes placed in the effluent. The amount of permeated oxygen increased both with the microwave power and with the number of membranes, since the former yields hotter effluents (>700 °C) and the latter increases the surface area available for permeation. The largest O 2 permeation flow was obtained for 21 membranes and a microwave power of 2550 W: ≃42 sccm or ≃4.8% of the available O 2 . These correspond to the highest performances of such a plasma-membrane reactor thus far. The permeated O 2 flow was also affected by the argon flow purging the membranes. Using one membrane, the flow of extracted oxygen decreased for an Ar flow below 250 sccm, while the opposite was observed with 10 membranes, yielding an increase in the oxygen flow from ≃25 to ≃28 sccm upon decreasing the total Ar flow below 2500 sccm. Key aspects that must be tackled for the design and testing of a plasma-membrane prototype that aims to remove O 2 beyond 90% are discussed.

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Advancing CO₂ to CO conversion: Detailed impact analysis of atmospheric molecules in an ultrashort pulse laser filament plasma reactor

Wang,

Deng,

Huang

et al. 2024

Micro & Optical Tech Letters

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Capturing carbon dioxide (CO2) and transforming it into valuable fuels offers a dual benefit: the potential to reduce atmospheric CO2 levels and decrease our dependency on fossil fuels. Plasma‐assisted CO2 to carbon monoxide (CO) conversion stands out within the various CO2 recycling methods, with research primarily emphasizing its energy efficiency and conversion efficacy. However, investigations of CO2 conversion under real air conditions are relatively scarce, and the effects of the other atmospheric molecules on the CO2 conversion process require further exploration. We have induced plasma chemical reactions by generating ultrashort pulse laser filaments inside a sealed‐off cavity with variable air pressures. Simultaneously, we applied mid‐infrared laser absorption spectroscopy to monitor the time evolution of the reaction products. The peak CO2‐to‐CO conversion ratio was achieved at an air pressure of 8000 Pa, which resulted in a CO concentration of 82 ppm. The experimental results suggested that nitrogen (N2) plays a promoting role in CO2‐to‐CO conversion, while the presence of oxygen (O2) seems to hinder the process. The hydroxyl radical (OH) arising from water molecules (H2O) limits the accumulation of CO at lower air pressures. However, at higher air pressures, the reduced OH radical concentration shows negligible impact on the CO2‐to‐CO conversion ratios. In addition, the study revealed that atmospheric plasmas produce a high concentration of hydrogen cyanide (HCN), which is directly proportional to the levels of ambient humidity. This research contributes to the development of strategies to mitigate the production of harmful gases like HCN in CO2 conversion, thereby promoting the ecofriendly conversion of atmospheric CO2.

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Enhancement of CO2 conversion in microwave plasmas using a nozzle in the effluent

Cited by 36 publications

References 20 publications

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

Proof of Concept for O₂ Removal with Multiple LCCF Membranes Accommodated in the Effluent of a CO₂ Plasma Torch

Advancing CO₂ to CO conversion: Detailed impact analysis of atmospheric molecules in an ultrashort pulse laser filament plasma reactor

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Enhancement of CO2 conversion in microwave plasmas using a nozzle in the effluent

Cited by 36 publications

References 20 publications

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

Proof of Concept for O2 Removal with Multiple LCCF Membranes Accommodated in the Effluent of a CO2 Plasma Torch

Advancing CO2 to CO conversion: Detailed impact analysis of atmospheric molecules in an ultrashort pulse laser filament plasma reactor

Contact Info

Product

Resources

About

Proof of Concept for O₂ Removal with Multiple LCCF Membranes Accommodated in the Effluent of a CO₂ Plasma Torch

Advancing CO₂ to CO conversion: Detailed impact analysis of atmospheric molecules in an ultrashort pulse laser filament plasma reactor