Bulletin of the American Physical Society
72nd Annual Gaseous Electronics Conference
Volume 64, Number 10
Monday–Friday, October 28–November 1 2019; College Station, Texas
Session ET3: Green Plasma Technologies I: Environmental and Energy Applications |
Hide Abstracts |
Chair: Miles Turner, Dublin City University Room: Century III |
Tuesday, October 29, 2019 1:45PM - 2:15PM |
ET3.00001: Electric Discharge Generation in MeOH Supercritical Fluid Invited Speaker: Sergey Leonov Electric breakdown and discharge propagation in supercritical fluids (SCF) mostly generated in CO2 and N2 were described in several works [S. Stauss et al, PSST, 27 (2018), 023003]. Study of the mechanisms of electric breakdown and discharge dynamics in SCFs is a fundamental challenge and promises well-recognized practical benefits in different engineering areas including fuel injection techniques, protection against deadly breakdowns in electrically-insulating liquids, etc. This study considers a self-sustained system where a high-voltage discharge first transfers a weakly-conductive liquid (MeOH) to a SC state, then exists in the SCF as an extended high-current plasma filament. The SCF plasma is generated in a rigid transparent test cell under the following conditions: discharge length up to 20mm; applied voltage up to 10kV; electrical current up to 100A; initial pressure P$=$1bar; maximal pressure within SCF up to 100bar. Diagnostics include electrical probes, fast camera imaging, schlieren visualization of the hydrodynamic processes, laser tracking of interfaces, and optical emission spectroscopy. A non-ideal plasma state is considered with electron density exceeding 3e19 cm-3 measured by Stark broadening of the H$\alpha $ line. Extra attention was paid for a phase of expansion and condensation of the SCF. In terms of nucleation dynamics, two different scenarios are discussed: ion-ion conductivity (liquid-like SCF) and electron-ion conductivity (gas-like SCF). The second scenario potentially yields a great charge accumulation and prevention of further condensation of the multiphase mixture. [Preview Abstract] |
Tuesday, October 29, 2019 2:15PM - 2:30PM |
ET3.00002: Treatment of liquids by low-current arc in ambient air for biomedical and agricultural applications Vladislav Gamaleev, Naoyuki Iwata, Jun-Seok Oh, Mineo Hiramatsu, Masafumi Ito Recently plasma treated water (PTW) is attracting a lot of attention owing to a huge number of possible applications in agriculture and medicine. Typically a low temperature atmospheric pressure plasma jets (APPJ) or dielectric barrier discharges (DBD) are used for treatment of water. However, in both cases of APPJ and DBD, production rate of RONS is low and irradiation of liquid takes a long time. In this work we developed compact generator for direct treatment of liquids by ambient air low-current arc (AALCA), which allows to perform treatment of any type of liquid regardless of its conductivity. It was found that treatment by AALCA is extremely efficient for delivery of reactive species to the liquid and concentrations of RONS after the treatment are several hundred times higher comparing to conventional APPJ and DBD plasma. It was confirmed by survival test of E.coli that produced PTW is having a strong bactericidal effect which remains event after storage of PTW for several days. Simple setup, cheap price and possibility of scaling are looking perspective for development of a tool for plasma treatment of large volumes of water which could be used in agriculture and medicine. In the presentation, plasma generation process and parameters of the plasma, the quantitative measurement of RONS delivered from the plasma and applicability of proposed method in agriculture and medicine will be demonstrated. [Preview Abstract] |
Tuesday, October 29, 2019 2:30PM - 2:45PM |
ET3.00003: Cavity ringdown measurement of OH(X) in the microwave plasma-assisted ignition Chuji Wang, Che A Fuh Cavity ringdown spectroscopy is employed to measure the absolute concentration of the ground state OH(X) radical at the ignition region in the microwave plasma-assisted combustion (PAC) of a premixed methane/air mixture. A 2.45 GHz solid state microwave source was used to generate the plasma used in this study. The PAC platform consisted of a triple-layered coaxial cylindrical quartz combustor with the argon plasma conducted in the innermost cylinder and the premixed methane/air as the coflow. This configuration allowed for the coupling of the plasma and reactants outside the combustor making the plasma-assisted ignition region accessible to the cavity ringdown beam. Optical emission spectroscopy and visual imaging were used to obtain information about the excited state species along with plasma and flame geometries, respectively. A single peak was observed in the excited state OH(A) emission profile in the hybrid zone whereas no OH(X) peak was observed in the hybrid zone. The representation of both OH(A) and OH(X) provides a complete picture of the role played by the OH radical. The results obtained further confirmed the hypothesis that OH(X) is more involved in the stabilization reactions whereas OH (A) is more prevalent in the ignition process. [Preview Abstract] |
Tuesday, October 29, 2019 2:45PM - 3:00PM |
ET3.00004: Gas Composition Changes in Heavy Oil Conversion by Submerged Multi-Phase Pulsed Plasmas Shariful Islam Bhuiyan, Kungpeng Wang, Abdullah Hill Baky, Christopher Campbell, David Staack, Howard Jemison In this study we investigated the changes in gas phase composition that occurs under submerged multi-phase pulsed plasmas in hydrocarbons. Discharges were generated under mineral oil along with initial processing gas flow of methane. The spark gap was submerged under liquid and electrical breakdown happens as high voltage is applied. The discharge is characterized by nanosecond pulse duration and low energy per pulse. These high frequency high voltage pulses generate low temperature atmospheric pressure non-equilibrium plasma that interact with the surrounding liquids and vapors by cracking and reforming the hydrocarbon molecules. A closed system was developed with recirculating gas flow. Gas chromatography was used to analyze the processing gas. Preliminary results show methane mole concentration decreases to 50{\%} while hydrogen concentration increases to 40{\%} and there is a 15{\%} pressure rise in the system. Other compounds formed by plasma chemistry include formation of acetylene, ethane, ethylene, propane, propylene, butane and pentane in small percentages. However, the overall mass of the gases decreases and stoichiometric analysis show absorption of CH radicals into liquid. These results indicate gas to liquid conversion with plasma treatment in oil. [Preview Abstract] |
Tuesday, October 29, 2019 3:00PM - 3:15PM |
ET3.00005: Stochastic Optimization of a Uranium Reaction Mechanism Using Plasma Flow Reactor Measurements Mikhail Finko, Davide Curreli, Magdi Azer, Batikan Koroglu, Timothy Rose, David Weisz, Jonathan Crowhurst, Harry Radousky Despite years of study, the chemical processes governing the formation of nuclear debris in a condensing nuclear fireball are still poorly understood. In particular, most chemical and plasma chemical reaction pathways responsible for forming uranium molecular species remain either unknown or unverified. We address this issue by utilizing a coupled Monte Carlo Genetic Algorithm approach to optimize a uranium reaction mechanism with respect to emission measurements from a uranium plasma flow reactor. The plasma flow reactor presents an ideal experimental system for optimization due to the spatio-temporal correlation of the reactor, which allows it to be modeled by a simple global kinetic model. As a result, the complex parameter space of the uranium reaction mechanism can be reliably optimized to produce an experimentally corroborated set of reaction pathways and rate coefficients. This effort comprises a first step towards producing a comprehensive experimentally validated reaction mechanism of uranium molecular species formation. [Preview Abstract] |
Tuesday, October 29, 2019 3:15PM - 3:45PM |
ET3.00006: Interaction of plasma with organic liquids: Waste-free epoxidation Invited Speaker: Felipe Iza Advancements in non-thermal plasmas operating at atmospheric pressure have made possible novel processing of liquids that were not conceivable in conventional vacuum systems due to vapour pressure limitations. In addition to the rapidly growing use in plasma medicine, plasma agriculture, nanoparticle synthesis and water treatment, the interaction of plasmas with organic liquids opens two additional avenues of research: the development of novel organic compounds for the characterisation of plasmas and the use of gas plasma in novel chemical synthesis processes. Of special interest are novel chemical synthesis processes in which one has the potential of eliminating waste streams. In this presentation, we will focus on plasma-driven epoxidation, i.e. the oxidation of alkenes to form epoxides. Owing to the lack of reactivity of oxygen and other small molecular oxygen donors with alkenes, peracids are currently used to drive epoxidation reactions. A widely used peracid is m-chloroperbenzoic acid (mCPBA), which although effective, is also corrosive, explosive, leads to chlorinated waste products and even under optimum epoxidation conditions, it produces more than 10kg of waste stream per kg of oxygen transferred. As an alternative, we can use atomic oxygen generated in an atmospheric pressure plasma, which is delivered to a solution containing the target alkene. This completely eliminates the oxidant waste-stream of the process. Optimization in terms of plasma source configuration, gas composition and input power has allowed us to improve the selectivity and yield of epoxide formation from a few percent in early experiments to $\sim$80\%, which compares favourably with conventional epoxidation processes. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700