Article
Thermodynamics
Xinlu Han, Marco Lubrano Lavadera, Christian Brackmann, Zhihua Wang, Yong He, Alexander A. Konnov
Summary: The formation of nitric oxide (NO) in methane (CH4) flames has been extensively studied, but discrepancies between simulations using different kinetic mechanisms and experimental results persist. Experimental data was collected for NO formation in post-flame zones of CH4+O2+N2 flames with varying oxygen ratios. Analysis showed that thermal-NO production plays a key role in the increase of NO mole fraction in stoichiometric and fuel-lean flames as oxygen ratio increases.
COMBUSTION AND FLAME
(2021)
Article
Physics, Fluids & Plasmas
Michael Hinshelwood, Gottlieb S. Oehrlein
Summary: This study investigates the oxidation of plasma-produced NO over a Pt/Al2O3 catalyst using in-situ infrared spectroscopy. The results show that Pt-Al2O3 increases the oxidation of NO at 350 degrees Celsius, and the oxidation of NO is limited by Pt-O at high temperatures.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Multidisciplinary
Toshimitsu Nomura, Hiroaki Kakiuchi, Hiromasa Ohmi
Summary: In this study, 'black Si' with Si nanocone structures was prepared using moderate-pressure H-2 plasma, and an O-2 concentration of 20% in the additives resulted in a Si surface with very low light reflectance.
Article
Energy & Fuels
Mahboobeh Ejtemaei, Sepehr Sadighi, Mehdi Rashidzadeh, Sirous Khorram, Jan O. Back, Parastoo Delir Kheyrollahi Nezhad, Simon Penner, Michael F. Noisternig, Dariush Salari, Aligholi Niaei
Summary: In this study, the surface modification of attapulgite-bounded zeolite A by N-2/O-2 glow discharge plasma was investigated. It was found that the O-2 plasma treatment increased the surface acidity, while the N-2 plasma treatment decreased the acidity. The N-2 plasma-treated samples showed reduced coke formation and higher water sorption capacity.
CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION
(2022)
Article
Engineering, Environmental
Dan Wang, Tingchao Ji, Qi Jing, Wei He, Zeyuan Fan, Dejian Wu, Xinming Qian
Summary: The study investigated the minimum ignition temperature of three typical organic dusts in various atmospheres, revealing that CO2 is most effective in reducing ignition sensitivity. The risk of dust explosions significantly increases with higher oxygen mole fraction, as demonstrated by a logarithmic reduction in MIT for the three dusts.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ye-Bin You, Young-Seok Lee, Si-Jun Kim, Chul-Hee Cho, In-Ho Seong, Won-Nyoung Jeong, Min-Su Choi, Shin-Jae You
Summary: This research reveals that the concentration of oxygen radicals measured by OES does not exactly match the ashing rate in the oxygen plasma ashing process. Considering plasma parameters, such as electron density, can solve this issue.
Article
Chemistry, Physical
Ahmad Shaker, Seyed Abdolmehdi Hashemi, E. Ebrahimi Fordoei
Summary: This study numerically investigates the Moderate or Intense Low-oxygen Dilution (MILD) combustion of a syngas fuel under different conditions. The results show that the chemical and physical effects of replacing N2 with CO2 have different influences on flame structure, ignition delay time, and heat release rate under different preheating temperatures. The sensitivity analysis reveals that certain reactions are responsible for lower heat release rate and higher ignition delay time in oxy-fuel MILD combustion.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Energy & Fuels
Xinlu Han, Zhihua Wang, Riyi Lin, Alexander A. Konnov
Summary: This study investigates the phenomenon of SAFT in the CH4 + O2 + N2 and NH3 + O2 + N2 flames and examines the relationship between SAFT and laminar burning velocities. Experimental measurements and simulations reveal different SAFT regimes for CH4 and NH3 flames, and demonstrate the connection between SAFT extent and laminar burning velocity.
Article
Energy & Fuels
Peng Ma, Qian Huang, Yuanping Yang, Renshan Ji, Shuiqing Li
Summary: Flexible oxy-coal combustion with carbon capture, utilization, and storage (CCUS) is crucial for achieving carbon neutrality in renewable energy. This study investigates coal stream ignition and soot evolution in different O-2/N-2 and O-2/CO2 atmospheres. Results show that the O-2/CO2 case delays ignition and reduces soot volume fraction compared to the conventional O-2/N-2 atmosphere. The effect of oxygen fraction on soot volume fraction differs between the two atmospheres. Additionally, the coal rank and local temperature affect soot formation ability.
Article
Chemistry, Physical
Arthur M. Halpern
Summary: The dimerization thermodynamics of N-2 and O-2, as well as the heterodimer (N-2)(O-2), have been determined using the method of Stogryn and Hirschfelder. The rankings of K-eq and Delta H for the three dimers are (N-2)(O-2) > (O-2)(O-2) > (N-2)(N-2). The mole fraction composition of the dimers in the atmosphere suggests that they are fifth to seventh in abundance, between CO2 and Ne.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Thermodynamics
Hongtao Zhong, Xingqian Mao, Aric C. Rousso, Charles L. Patrick, Chao Yan, Wenbin Xu, Qi Chen, Gerard Wysocki, Yiguang Ju
Summary: This study investigates the kinetics of low-temperature pyrolysis and oxidation of n-dodecane/O-2/N-2 mixtures in a repetitive nanosecond discharge experimentally and numerically. Results show that a nanosecond discharge can greatly accelerate the pyrolysis and oxidation of n-dodecane at low temperatures, with electronically excited N-2* playing an important role. Addition of n-dodecane reduces NO concentration, indicating a strong NO kinetic effect on plasma-assisted low-temperature combustion.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Materials Science, Multidisciplinary
Wan Soo Song, Ju Eun Kang, Sang Jeen Hong
Summary: This study presents an analysis of Si3N4 thin film etching using CF4/O-2 mixed with N-2 plasma based on optical emission spectroscopy (OES). The results reveal the effects of N-2 on the chemical species and quantity in CF4/O-2 plasma and its influence on the etch rate of Si3N4.
Article
Energy & Fuels
Liutao Sun, Kai Xie, Rui Sun, Zewu Zhang, Yonghong Yan, Mengfan Yuan, Jiangquan Wu
Summary: The present study investigates the effects of oxygen content in the oxidizer on the combustion behaviors of semicoke mixtures. The results show that increasing oxygen content leads to higher peak temperature, reduced high temperature region, and enhanced flue gas recirculation. The effects of char-oxygen and char-CO2 reactions are weakened when nitrogen is replaced by CO2. A high oxygen content and an O2/N2 atmosphere promote a homo-MILD combustion regime. Low NOx emissions can be achieved by regulating the oxy-MILD combustion regime.
Article
Chemistry, Multidisciplinary
Jie Zeng, Rulin Qiu, Jun Zhu
Summary: Density functional theory (DFT) calculations are performed to screen experimentally viable FLPs for small-molecule activation, including N-2. Aromaticity is found to play an important role in most of these activations. The thermodynamic stabilities and low reaction barriers of the activation products could advance the development of FLP towards small-molecule activation, including N-2, and require experimental verification.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Review
Physics, Applied
Jialin Liu, Lanlan Nie, Dawei Liu, Xinpei Lu
Summary: This paper provides an overview of the research in the field of nitrogen fixation (NF), discussing the main pathway for NO formation in N-2/O-2 mixtures and the involvement of N-2 in the Zeldovich mechanism. It also addresses the high energy consumption obstacle in plasma-assisted NF and the importance of understanding energy flow in the discharge process for improving NF energy efficiency. Furthermore, it discusses various new plasma NF devices reported in recent years.
PLASMA PROCESSES AND POLYMERS
(2023)
Article
Physics, Applied
S. -J. Klose, R. Bansemer, R. Brandenburg, J. H. van Helden
Summary: The density of Ar(3P2) metastable in the effluent of the cold atmospheric pressure plasma jet kINPen was studied as a function of feed gas humidity and gas curtain composition. It was found that with the addition of water to the feed gas, the excitation dynamics changed, leading to a reduction in the production and lifetime of Ar(3P2), resulting in decreased density near the nozzle.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Arunkumar Pandiyan, Vasileios Kyriakou, Dragos Neagu, Stefan Welzel, Adelbert Goede, Mauritius C. M. van de Sanden, Mihalis N. Tsampas
Summary: Surplus renewable electricity can be used to convert CO2 into CO, which is the basis of liquid fuels, enabling large-scale energy storage and the synthesis of fuel for long-haul transportation. High-temperature electrolysis and plasmolysis are two promising technologies. However, both face challenges. High-temperature electrolysis has high yield and efficiency but requires electrode materials to break the carbon-oxygen double bond. Plasmolysis, on the other hand, has similar efficiency and is easy to scale up, but gas separation and recuperation are necessary due to the mixing of CO, O-2, and residual CO2. This study demonstrates the coupling of the two processes to overcome the main bottleneck of plasmolysis and achieve efficient CO2 conversion into valuable CO feedstock.
JOURNAL OF CO2 UTILIZATION
(2022)
Article
Nanoscience & Nanotechnology
Usman Mushtaq, Stefan Welzel, Rakesh K. Sharma, M. C. M. van de Sanden, Mihalis N. Tsampas
Summary: A method to overcome fabrication challenges for the development of efficient and robust electrode-supported P-SOCs (protonic ceramic solid oxide cells) was discussed. The study optimized material synthesis and fabrication procedures and evaluated the performance and stability of the cells.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Physics, Fluids & Plasmas
F. Sigeneger, J. Ellis, J. Harhausen, N. Lang, J. H. van Helden
Summary: A self-consistent fluid model has been developed and employed to model an electron cyclotron resonance driven hydrogen plasma at low pressure. The model provides key insights into the mutual interaction of microwave propagation, power density, plasma generation, and species transport. Verification experiments demonstrate good agreement with measured ion current density, floating potential, and atomic hydrogen density, confirming the validity of the simulation.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
J. Boecker, A. Puth, A. Pipa, J-P H. Van Helden, J. Roepcke, H. Biermann, A. Dalke
Summary: In this study, plasma nitrocarburizing using an active screen made of carbon fiber-reinforced carbon was carried out. It was found that by varying the process gas atmosphere and adding oxygen-containing fresh gases, nitrogen-rich, single-phase ε-compound layers can be generated while suppressing the formation of cementite.
HTM-JOURNAL OF HEAT TREATMENT AND MATERIALS
(2022)
Article
Physics, Fluids & Plasmas
J. R. Wubs, U. Macherius, K-D Weltmann, X. Lue, B. Roeben, K. Biermann, L. Schrottke, H. T. Grahn, J. H. van Helden
Summary: This paper describes the first application of terahertz quantum cascade lasers for high-resolution absorption spectroscopy on plasmas. Absolute densities of ground state atomic oxygen were directly obtained by using the fine structure transition at approximately 4.75 THz. The presented method is well suited to measure atomic oxygen densities and closes the THz gap for quantitative atomic density measurements in harsh environments such as plasmas.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
X. Lue, B. Roeben, K. Biermann, J. R. Wubs, U. Macherius, K-D Weltmann, J. H. van Helden, L. Schrottke, H. T. Grahn
Summary: We present terahertz (THz) quantum-cascade lasers (QCLs) based on GaAs/AlAs heterostructures, which emit single-mode radiation at 3.360, 3.921, and 4.745 THz, corresponding to fine-structure transitions of Al atoms, N+ ions, and O atoms. These THz QCLs can operate in continuous-wave mode with low electrical pump power and maintain a tuning range of more than 5 GHz. The single-mode operation and intrinsic tuning range of these lasers make them suitable for high-resolution absorption spectroscopy to determine the absolute densities of Al atoms, N+ ions, and O atoms in plasmas.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
C. Douat, S. Ponduri, T. Boumans, O. Guaitella, S. Welzel, E. Carbone, R. Engeln
Summary: This study investigates the dissociation of CO2 in a symmetric pin-to-pin dielectric barrier discharge (DBD). The number of filaments per half cycle follows a power-law as a function of the injected power and remains constant regardless of pressure or other process parameters. The CO2 conversion is found to be proportional to specific energy input (SEI) even at the single filament level.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Saeed M. Jafarpour, Andrei V. Pipa, Alexander Puth, Anke Dalke, Juergen Roepcke, Jean-Pierre H. van Helden, Horst Biermann
Summary: Recent technological development of utilizing an active screen made of solid carbon in plasma-assisted thermochemical diffusion treatments provides new possibilities for controlling the treatment environment and ensuring reproducible material responses. This systematic study investigates the simultaneous variation of H-2-N-2 feed-gas composition and bias plasma power on the treatment environment and material response during active-screen plasma nitrocarburizing (ASPNC) of AISI 316L stainless steel. The study demonstrates that the nitriding effect is increased under biased conditions and higher N-2 amounts, while the carburizing effect is increased under non-biased conditions, regardless of the feed-gas composition.
Article
Physics, Applied
J. R. Wubs, L. Invernizzi, K. Gazeli, U. Macherius, X. Lu, L. Schrottke, G. Lombardi, K. -D. Weltmann, J. H. van Helden
Summary: This research demonstrates that Terahertz (THz) absorption spectroscopy is an accurate technique for measuring atomic oxygen densities in plasmas, as it yields similar results to picosecond two-photon absorption laser induced fluorescence (TALIF) measurements. The study shows that both diagnostic methods exhibit similar changes in atomic oxygen density when varying the applied power and gas pressure.
APPLIED PHYSICS LETTERS
(2023)
Correction
Physics, Applied
J. R. Wubs, L. Invernizzi, K. Gazeli, U. Macherius, X. Lu, L. Schrottke, G. Lombardi, K. -D. Weltmann, J. H. van Helden
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Fluids & Plasmas
A. Pipa, A. Puth, J. Boecker, S. M. Jafarpour, A. Dalke, H. Biermann, J. Roepcke, J. H. van Helden
Summary: This study investigated the density evolution of HCN 2-H-2 gas mixtures with the addition of CH4 or O-2 using a simplified kinetic model. The results showed that the chemical processes in the active screen plasma nitrocarburizing reactor had different characteristic times, which corresponded to the gas residence time, surface reactions, and surface reactions on the cold reactor walls.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
A. Pipa, A. Puth, J. Boecker, S. M. Jafarpour, A. Dalke, H. Biermann, J. Roepcke, J. H. van Helden
Summary: This work is focused on developing laser absorption spectroscopy (LAS) for plasma-assisted processes under industrial conditions. The interpretation of LAS measurements was revised to account for the temperature gradient along the absorption path in a thermochemical treatment reactor. The revision was based on the measurement of HCN.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
B. Harris, L. Kroes, A. S. Nave, E. Wagenaars, J. H. van Helden
Summary: Cold atmospheric plasma jets with small admixtures of water vapour are excellent sources of H2O2 for biomedical applications. However, the distribution of H2O2 is non-uniform and depends on the positioning relative to the plasma source. This study measured the spatial distribution of H2O2 number densities in the effluent of two popular plasma jets and found that the kINPen-sci plasma jet has a higher average H2O2 number density than the COST-Jet. Understanding H2O2 production and transport is important for optimizing its effects in biomedical applications.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Usman Mushtaq, Stefan Welzel, Rakesh K. Sharma, M. C. M. van de Sanden, Mihalis N. Tsampas
Summary: This study presents a detailed method to overcome fabrication challenges and develop efficient and robust electrode-supported P-SOCs. Through optimization of material synthesis, fabrication procedures, and thermal treatments, half-cells with good performance were successfully prepared and evaluated as an electrochemical hydrogen pump.
ACS APPLIED MATERIALS & INTERFACES
(2022)
