Numerical modeling and mechanism investigation of nanosecond-pulsed DBD plasma-catalytic CH4 dry reforming
About: This article is published in Journal of Physics D.The article was published on 2022-01-20. It has received 8 citations till now. The article focuses on the topics: Nanosecond & Carbon dioxide reforming.
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TL;DR: In this paper , the authors report a promising plasma process for the catalyst-free single-step conversion of CH4 and CO2 into higher value oxygenates (i.e., methanol, acetic acid, ethanol, and acetone) at ambient pressure and room temperature using a water-cooled dielectric barrier discharge (DBD) reactor.
27 citations
TL;DR: In this paper , a review of plasma-assisted reforming of methane (PARM) is presented from the perspective of reactor development, thermal and nonthermal PARM routes, and catalysis.
Abstract: Methane (CH4) is inexpensive, high in heating value, relatively low in carbon footprint compared to coal, and thus a promising energy resource. However, the locations of natural gas production sites are typically far from industrial areas. Therefore, transportation is needed, which could considerably increase the sale price of natural gas. Thus, the development of distributed, clean, affordable processes for the efficient conversion of CH4 has increasingly attracted people's attention. Among them are plasma technology with the advantages of mild operating conditions, low space need, and quick generation of energetic and chemically active species, which allows the reaction to occur far from the thermodynamic equilibrium and at a reasonable cost. Significant progress in plasma‐assisted reforming of methane (PARM) is achieved and reviewed in this paper from the perspectives of reactor development, thermal and nonthermal PARM routes, and catalysis. The factors affecting the conversion of reactants and the selectivity of products are studied. The findings from the past works and the insight into the existing challenges in this work should benefit the further development of reactors, high‐performance catalysts, and PARM routes.
11 citations
TL;DR: In this paper , a three-electrode reactor was designed and a suspended electrode was added to further improve the hydrogen production efficiency of microwave liquid-phase discharge, and the formation of bubbles during the discharge and the change characteristics of plasma morphology were studied after adding the suspended electrode.
4 citations
TL;DR: In this paper , a multi-layer feed-forward deep neural network was introduced into the plasma/plasma catalysis kinetics modeling, which enables the initial input parameters for kinetics simulation, such as reduced electric field (E/N), to be extracted from specific experimental data after the neural network has been well-trained.
3 citations
TL;DR: In this article , an innovative synthesis of higher alcohols from CH4-CH3OH was driven by a highly flexible nanosecond pulsed plasma, and the products distribution was strongly correlated with the electric field variation and reactants composition, and a maximum conversion of CH4 (35.9%) and CH3OH (77.4%) were obtained at the CH4/Ar ratio of 1:2.
Abstract: The single-step conversion of CH4 to higher alcohols without catalyst or complex processing is the dream solution both in C1 chemistry and the chemical industry. Here, an innovative synthesis of higher alcohols from CH4–CH3OH was driven by a highly flexible nanosecond pulsed plasma. Experimental results showed that the products distribution was strongly correlated with the electric field variation and reactants composition, and the maximum conversion of CH4 (35.9%) and CH3OH (77.4%) were obtained at the CH4/Ar ratio of 1:2. Interestingly, the addition of H2O and H2O2 effectively promoted the C2–C4 alcohols selectivity up to 19.4%. In addition, optical diagnostics were used to obtain active species distribution and integrated insights into the C–C coupling of higher alcohols generation. A possible reaction mechanism of CH4–CH3OH plasma was also discussed.
1 citations
References
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TL;DR: A direct stepwise method for converting methane into methanol with high selectivity over a copper-containing zeolite, based on partial oxidation with water, involving methane oxidation at CuII oxide active centers, followed by CuI reoxidation by water with concurrent formation of hydrogen.
Abstract: Direct functionalization of methane in natural gas remains a key challenge. We present a direct stepwise method for converting methane into methanol with high selectivity (~97%) over a copper-containing zeolite, based on partial oxidation with water. The activation in helium at 673 kelvin (K), followed by consecutive catalyst exposures to 7 bars of methane and then water at 473 K, consistently produced 0.204 mole of CH3OH per mole of copper in zeolite. Isotopic labeling confirmed water as the source of oxygen to regenerate the zeolite active centers and renders methanol desorption energetically favorable. On the basis of in situ x-ray absorption spectroscopy, infrared spectroscopy, and density functional theory calculations, we propose a mechanism involving methane oxidation at CuII oxide active centers, followed by CuI reoxidation by water with concurrent formation of hydrogen.
495 citations
TL;DR: This Review critically examines the catalytic mechanisms relevant to each specific application of plasma catalysis, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases.
Abstract: Thermal-catalytic gas processing is integral to many current industrial processes. Ever-increasing demands on conversion and energy efficiencies are a strong driving force for the development of alternative approaches. Similarly, synthesis of several functional materials (such as nanowires and nanotubes) demands special processing conditions. Plasma catalysis provides such an alternative, where the catalytic process is complemented by the use of plasmas that activate the source gas. This combination is often observed to result in a synergy between plasma and catalyst. This Review introduces the current state-of-the-art in plasma catalysis, including numerous examples where plasma catalysis has demonstrated its benefits or shows future potential, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases. The underlying mechanisms governing these applications, as resulting from the interaction between the plasma and the catalyst, rend...
485 citations
TL;DR: Schram et al. as discussed by the authors presented a useful contribution to the basic phenomena in nitrogen, oxygen and other atmospheric gases, which includes basic introductory chapters on relaxation in translational, rotational, short and vibrational distribution and on the physics of electron excitation and electron distribution functions.
Abstract: The book Plasma Kinetics in Atmospheric Gases is a worthwhile contribution to the basic phenomena in nitrogen, oxygen and other atmospheric gases. It contains basic introductory chapters on relaxation in translational, rotational (short) and vibrational (extensive) distribution and on the physics of electron excitation and electron distribution functions. In the latter, electron beam excitation (i.e. high electron energies) are included. In the following chapters, much detail follows on spectroscopic constants of various molecules, molecular fragments and ions, on transport coefficients such as diffusion coefficients, relaxation times and rates. The transfer between translational energies and rotational and vibrational energies are treated in this context. Many (electron) excitation rates, electronic lifetimes and rates for chemical reactions for molecules, fragments and ions are given. The background part of the book is completed with an introductory chapter on wall reactions and accommodation coefficients. In this way an enormous wealth of data for nitrogen-, oxygen- and hydrogen-containing molecules can be found in this book. The book continues with the discussion of discharge physics in pure nitrogen and oxygen, and in mixtures. Some examples are given of applications, of which cleaning of atmospheric gases is, in my view, one of the most important. The many processes which play a role in the ionosphere are another important example of the application of the basic material for nitrogen, oxygen and other molecules. The kinetics which play a role in re-entry problems, and which have a limiting effect on the heat flux, are another example of the application of the plasma chemistry of nitrogen and oxygen gases. In this context fits also a short treatment of acoustic and shock waves, with which the book closes. The structure of the book is that of separate chapters which are in a logical order and follow naturally from the preceding ones. The chapters are separate in the sense that there are not many cross-references between them and all contain their own reference lists. Most of the reference lists (but not all) are extensive and contain recent references. A particular value of the book is the coverage of Russian references. However, I missed in several chapters some references as, for example, a recent book by Ricard on a related subject and other publications of, for example, French and Japanese groups which work on N2 and O2 discharges. This means also that some rates are given without mention of the discussion on them. Nevertheless, in my view this is a very useful book and I will use it extensively. The physics and chemistry of nitrogen- and oxygen-containing plasmas present a great challenge, and much is still unknown and not fully understood, in particular also in combination with surface processes. In this research the book will prove to be a valuable contribution. Professor D C Schram Department of Physics, Eindhoven University of Technology, 5600 MB Eindhoven
484 citations
TL;DR: Theoretical aspects and evolution of surface diffusion studies with an emphasis on non-metallic adsorbates at metal surfaces are discussed in this article, with the main experimental results tabulated.
401 citations
TL;DR: In this paper, a review provides a contemporary assessment of progresses recorded on synergistic interplay among catalyst components (active metals, support, promoters and binders) during dry reforming using state-of-the-art experimental and theoretical techniques.
Abstract: The abrupt and massive deactivation of methane dry reforming catalysts especially Ni-based is still a monumental impediment towards its industrialization and commercialization for production of value-added syngas via Fischer-Tropsch process. The need for further and more critical understanding of inherent and tailored interactions of catalyst components for performance and stability enhancement during reforming reaction cannot be over-emphasized. This review provides a contemporary assessment of progresses recorded on synergistic interplay among catalyst components (active metals, support, promoters and binders) during dry reforming using state-of-the-art experimental and theoretical techniques. Advancements achieved during interplay leading to improvements in properties of existing catalysts and discovery of novel ones were stated and expatiated. Reaction pathways, catalytic activities, selection of appropriate synthesis route and metal/support deactivation via sintering or carbon deposition have over time been successfully studied and explained using information from these crucial component interactions. This perspective describes the roles of these interactions and their applications towards development of robust catalysts configurations for successful industrial applications.
367 citations