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Author Ahmadi Eshtehardi, H. url  doi
openurl 
  Title Combined computational-experimental study on plasma and plasma catalysis for N2 fixation Type Doctoral thesis
  Year (down) 2024 Publication Abbreviated Journal  
  Volume Issue Pages 160 p.  
  Keywords Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Humanity feels the urge of shifting to a sustainable society more than at any other time in its history. Electrification of chemical industry plays a key role in this transition. The possibility of producing fertilizers from air using renewable electricity, and simultaneously, no greenhouse gas emission, resulted in an increasing interest toward plasma technology as a solution for electrification of a part of the chemical industry in the past few years. Additionally, the activation of nitrogen molecules by vibrational and electronic excitation reactions in plasma can lead to an energy-efficient process. Last but not least, the modularity (fast on/off characteristic) of plasma technology makes it capable of using intermittent renewable electricity on site for the production of fertilizers using air. All these advantages offered by plasma technology make it a potential solution for the on-site production of fertilizers in small and decentralized plants using air and renewable electricity, which leads to a considerable reduction in fertilizer production and transportation costs. However, industrialization of plasma-based NF suffers from several challenges, including challenges of plasma catalysis for the selective production of desired species, the high energy cost of plasma-based NF compared to current industrial processes, and the design and development of scaled up and energy-efficient plasma reactors for industrial purposes. In the framework of this thesis we have tried to add to the state-of-the-art (SOTA) in plasma-based NOx production and deal with its limitations using a combination of experimental and modelling work.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2024-06-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:205246 Serial 9139  
Permanent link to this record
 

 
Author Tsonev, I.; Ahmadi Eshtehardi, H.; Delplancke, M.-P.; Bogaerts, A. doi  openurl
  Title Importance of geometric effects in scaling up energy-efficient plasma-based nitrogen fixation Type A1 Journal article
  Year (down) 2024 Publication Sustainable energy & fuels Abbreviated Journal  
  Volume Issue Pages 1-19  
  Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Despite the recent promising potential of plasma-based nitrogen fixation, the technology faces significant challenges in efficient upscaling. To tackle this challenge, we investigate two reactors, i.e., a small one, operating in a flow rate range of 5-20 ln min-1 and current range of 200-500 mA, and a larger one, operating at higher flow rate (100-300 ln min-1) and current (400-1000 mA). Both reactors operate in a pin-to-pin configuration and are powered by direct current (DC) from the same power supply unit, to allow easy comparison and evaluate the effect of upscaling. In the small reactor, we achieve the lowest energy cost (EC) of 2.8 MJ mol-1, for a NOx concentration of 1.72%, at a flow rate of 20 ln min-1, yielding a production rate (PR) of 33 g h-1. These values are obtained in air; in oxygen-enriched air, the results are typically better, at the cost of producing oxygen-enriched air. In the large reactor, the higher flow rates reduce the NOx concentration due to lower SEI, while maintaining a similar EC. This stresses the important effect of the geometrical configuration of the arc, which is typically concentrated in the center of the reactor, resulting in limited coverage of the reacting gas flow, and this is identified as the limiting factor for upscaling. However, our experiments reveal that by changing the reactor configuration, and thus the plasma geometry and power deposition mechanisms, the amount of gas treated by the plasma can be enhanced, leading to successful upscaling. To obtain more insights in our experiments, we performed thermodynamic equilibrium calculations. First of all, they show that our measured lowest EC closely aligns with the calculated minimum thermodynamic equilibrium at atmospheric pressure. In addition, they reveal that the limited NOx production in the large reactor results from the contracted nature of the plasma. To solve this limitation, we let the large reactor operate in so-called torch configuration. Indeed, the latter enhances the NOx concentrations compared to the pin-to-pin configuration, yielding a PR of 80 g h-1 at an EC of 2.9 MJ mol-1 and NOx concentration of 0.31%. This illustrates the importance of reactor design in upscaling. With the focus on feasibility evaluation of scaling-up plasma-based nitrogen fixation by combined experiments and thermodynamic modelling, we aim to tackle the challenge of design and development of an energy-efficient and scaled-up plasma reactor.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001203657700001 Publication Date 2024-04-11  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:205435 Serial 9155  
Permanent link to this record
 

 
Author Van Alphen, S.; Ahmadi Eshtehardi, H.; O'Modhrain, C.; Bogaerts, J.; Van Poyer, H.; Creel, J.; Delplancke, M.-P.; Snyders, R.; Bogaerts, A. pdf  url
doi  openurl
  Title Effusion nozzle for energy-efficient NOx production in a rotating gliding arc plasma reactor Type A1 Journal article
  Year (down) 2022 Publication Chemical Engineering Journal Abbreviated Journal Chem Eng J  
  Volume 443 Issue Pages 136529  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Plasma-based NOx production is of interest for sustainable N2 fixation, but more research is needed to improve its performance. One of the current limitations is recombination of NO back into N2 and O2 molecules immediately after the plasma reactor. Therefore, we developed a novel so-called “effusion nozzle”, to improve the perfor­mance of a rotating gliding arc plasma reactor for NOx production, but the same principle can also be applied to other plasma types. Experiments in a wide range of applied power, gas flow rates and N2/O2 ratios demonstrate an enhancement in NOx concentration by about 8%, and a reduction in energy cost by 22.5%. In absolute terms, we obtain NOx concentrations up to 5.9%, at an energy cost down to 2.1 MJ/mol, which are the best values reported to date in literature. In addition, we developed four complementary models to describe the gas flow, plasma temperature and plasma chemistry, aiming to reveal why the effusion nozzle yields better performance. Our simulations reveal that the effusion nozzle acts as very efficient heat sink, causing a fast drop in gas tem­perature when the gas molecules leave the plasma, hence limiting the recombination of NO back into N2 and O2. This yields an overall higher NOx concentration than without the effusion nozzle. This immediate quenching right at the end of the plasma makes our effusion nozzle superior to more conventional cooling options, like water cooling In addition, this higher NOx concentration can be obtained at a slightly lower power, because the effusion nozzle allows for the ignition and sustainment of the plasma at somewhat lower power. Hence, this also explains the lower energy cost. Overall, our experimental results and detailed modeling analysis will be useful to improve plasma-based NOx production in other plasma reactors as well.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000800010600003 Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1385-8947 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 15.1 Times cited Open Access OpenAccess  
  Notes This research was supported by the Excellence of Science FWO-FNRS project (FWO grant ID GoF9618n, EOS ID 30505023), the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 810182 – SCOPE ERC Synergy project), and through long-term structural funding (Methusalem). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (depart­ment EWI) and the UAntwerpen. Approved Most recent IF: 15.1  
  Call Number PLASMANT @ plasmant @c:irua:188283 Serial 7057  
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Author Jardali, F.; Van Alphen, S.; Creel, J.; Ahmadi Eshtehardi, H.; Axelsson, M.; Ingels, R.; Snyders, R.; Bogaerts, A. pdf  url
doi  openurl
  Title NOxproduction in a rotating gliding arc plasma: potential avenue for sustainable nitrogen fixation Type A1 Journal article
  Year (down) 2021 Publication Green Chemistry Abbreviated Journal Green Chem  
  Volume 23 Issue 4 Pages 1748-1757  
  Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract The fast growing world population demands food to survive, and nitrogen-based fertilizers are essential to ensure sufficient food production. Today, fertilizers are mainly produced from non-sustainable fossil fuels<italic>via</italic>the Haber–Bosch process, leading to serious environmental problems. We propose here a novel rotating gliding arc plasma, operating in air, for direct NO<sub>x</sub>production, which can yield high nitrogen content organic fertilizers without pollution associated with ammonia emission. We explored the efficiency of NO<sub>x</sub>production in a wide range of feed gas ratios, and for two arc modes: rotating and steady. When the arc is in steady mode, record-value NO<sub>x</sub>concentrations up to 5.5% are achieved which are 1.7 times higher than the maximum concentration obtained by the rotating arc mode, and with an energy consumption of 2.5 MJ mol<sup>−1</sup>(or<italic>ca.</italic>50 kW h kN<sup>−1</sup>);<italic>i.e.</italic>the lowest value so far achieved by atmospheric pressure plasma reactors. Computer modelling, using a combination of five different complementary approaches, provides a comprehensive picture of NO<sub>x</sub>formation in both arc modes; in particular, the higher NO<sub>x</sub>production in the steady arc mode is due to the combined thermal and vibrationally-promoted Zeldovich mechanisms.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000629630600021 Publication Date 2021-01-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1463-9262 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 9.125 Times cited Open Access OpenAccess  
  Notes Fonds Wetenschappelijk Onderzoek, GoF9618n 30505023 ; H2020 European Research Council, 810182 ; This research was supported by a Bilateral Project with N2 Applied, the Excellence of Science FWO-FNRS project (FWO grant ID GoF9618n, EOS ID 30505023) and by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no 810182 – SCOPE ERC Synergy project). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UAntwerpen. We also thank J.-L. Liu for the RGA design, L. Van ‘t dack and K. Leyssens for MS calibration and practical support, and K. Van ‘t Veer for the fruitful discussions on plasma kinetic modelling and for calculating the electron energy losses. Approved Most recent IF: 9.125  
  Call Number PLASMANT @ plasmant @c:irua:176022 Serial 6678  
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