共查询到20条相似文献,搜索用时 15 毫秒
1.
Stratton B. C. Knight R. Mikkelsen D. R. Blutke A. Vavruska J. 《Plasma Chemistry and Plasma Processing》1999,19(2):191-216
The technical feasibility of using an induction-coupled plasma (ICP) torch to synthesize ozone at atmospheric pressure is explored. Ozone concentrations up to ~250 ppm were achieved using a thermal plasma reactor system based on an ICP torch operating at 2.5 MHz and ~11 kVA with an argon/oxygen mixture as the plasma-forming gas. The corresponding production rate and yield were ~20 g ozone/hr and ~2g ozone/kWh, respectively. A gaseous oxygen quench formed ozone by rapid mixing of molecular oxygen with atomic oxygen produced by the torch. The ozone concentration in the reaction chamber was measured by Fourier Transform infrared (FTIR) spectroscopy over a wide range of experimental conditions and configurations. The geometry of the quench gas flow, the quench flow velocity, and the quench flow rate played important roles in determining the ozone concentration. The ozone concentration was sensitive to the torch RF power, but was insensitive to the torch gas flow rates. These observations are interpreted within the framework of a simple model of ozone synthesis. 相似文献
2.
Atsushi Kuwabara Shin-ichi Kuroda Hitoshi Kubota 《Plasma Chemistry and Plasma Processing》2008,28(2):263-271
We have finally succeeded in producing the plasma jet by use of the surface discharge plasma torch that can be expected to
make larger the diameter of torch in the comparatively easy way. It can be checked that the active species in the jet obtained
are different depending on the direction of connection, and also it was clearly found that much O and N2 is included in them. Consequently, etching was confirmed at the position of 10 mm from the torch end in the surface treatment
of polypropylene film, but etching was not confirmed at the position of 20 mm. 相似文献
3.
Mirosław Dors Helena Nowakowska Mariusz Jasiński Jerzy Mizeraczyk 《Plasma Chemistry and Plasma Processing》2014,34(2):313-326
Results of chemical kinetics modeling in methane subjected to the microwave plasma at atmospheric pressure are presented in this paper. The reaction mechanism is based on the methane oxidation model without reactions involving nitrogen and oxygen. For the numerical calculations 0D and 1D models were created. 0D model uses Calorimetric Bomb Reactor whereas 1D model is constructed either as Plug Flow Reactor or as a chain of Plug Flow Reactor and Calorimetric Bomb Reactor. Both models explain experimental results and show the most important reactions responsible for the methane conversion and production of H2, C2H2, C2H4 and C2H6 detected in the experiment. Main conclusion is that the chemical reactions in our experiment proceed by a thermal process and the products can be defined by considering thermodynamic equilibrium. Temperature characterizing the methane pyrolysis is 1,500–2,000 K, but plasma temperature is in the range of 4,000–5,700 K, which means that methane pyrolysis process is occurring outside the plasma region in the swirl gas flowing around the plasma. 相似文献
4.
Rocío Rincón Margarita Jiménez José Muñoz Manuel Sáez María Dolores Calzada 《Plasma Chemistry and Plasma Processing》2014,34(1):145-157
Molecular hydrogen production from ethanol decomposition by two microwave atmospheric pressure plasma sources (surfatron and Torche a Injection Axiale sur Guide d’Onde (TIAGO) torch) was studied by optical emission spectroscopy and mass spectrometry. In both cases ethanol was almost completely decomposed, thus giving place to molecular hydrogen. However, the atmosphere surrounding the discharge significantly influences the overall decomposition process. When the surfatron is used, C2H2 and CO are obtained as exhaust gases. Likewise, H2O and HCN are also detected at plasma exit when sustained with the TIAGO torch. 相似文献
5.
The excitation capability of an argon microwave plasma flame expanded at atmospheric pressure has been studied. For this purpose, argon with different proportions of nitrogen was introduced at the end of the expanded flame, where the population densities of the atomic argon levels were still high enough. Optical emission spectra allowed the identification of different excited species in the plasma. When argon containing nitrogen was added at the end of the plasma flame, all argon lines emitted in this region were highly quenched, emission due to species containing nitrogen (NH, CN) was enhanced and a noticeable increase in the emission of N2 (C 3Πu ? B 3Πg) was observed. On the contrary, the weak emission of $ {\text{N}}_{2}^{ + } \left( {B^{ 2} \sum_{u}^{ + } - X^{ 2} \sum_{g}^{ + } } \right) $ was scarcely affected. According to these results it is possible to conclude that metastable argon atoms from the expanded flame are the main energy carriers when generating N2 reactive species in this plasma zone. 相似文献
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7.
Hydrogen production from methane reforming using the partial oxidation reaction is carried out using a bipolar pulse-driven
plasma reactor operating at atmospheric pressure. The influence of axial and radial injections of CH4 and O2 on the reforming performance is investigated in conjunction with the spatial distribution of their spectral emissions by
varying the O2/C ratio at a fixed discharge power. With increasing the O2/C ratio, the axial injection achieves the better conversion and efficiency. The measurement of spectral emissions reveals
that the higher efficiency of axial injection is caused by its efficient use of oxidation reaction heat. 相似文献
8.
Chen W. L. T. Heberlein J. Pfender E. Pateyron B. Delluc G. Elchinger M. F. Fauchais P. 《Plasma Chemistry and Plasma Processing》1995,15(3):559-579
Plasma Chemistry and Plasma Processing - Because of the importance of having reliable transport coefficients for argon/helium mixtures available, viscosities and thermal conductivities of such... 相似文献
9.
同轴表面波激励器和微波等离子体炬是两种获得微波等离子体(MWP)的装置,本文比较了用这两种装置获得的MWP作原子发射光谱法光源时的分析性能,结果表明这两种装置各有优点,但微波等离子体炬效果更好。 相似文献
10.
Direct current (dc) plasma torch with inter-electrode inserts has the merits of fixed arc length, relative high enthalpy and
may show advantages in future plasma processes where stability and controllability are must-have. Energy fluctuations in the
plasma may result from power supply ripple, arc length variation, and/or acoustic oscillation. Using an improved power supply
with a flat waveform, the characteristics of an argon plasma energy instabilities under reduced pressure were studied by means
of simultaneously monitoring the arc voltage and arc current spectrum. Dependence of the arc fluctuation behavior on the plasma
generating parameters, such as the current intensity, the plasma gas flow rates and the vacuum chamber pressure were investigated
and discussed. Results show that the plasma torch has a typical U-shaped voltage-ampere characteristic (VAC). The correlation
between the VAC and the probability of energy distributions was studied. Through pressure measurements at the cathode cavity
and the vacuum chamber, the existence of sonic flow in the inter-electrode insert channel was confirmed. 相似文献
11.
YU Bingwen JIN Wei ZHU Dan YING Yangwei YU Haixiang SHAN Jin XU Chen LIU Wenlong JIN Qinhan 《高等学校化学研究》2016,32(4):549-555
In order to obtain a stable plasma and improve the performance of the torch for atomic emission spectroscopy(AES), the structure of microwave plasma torch(MPT) was analyzed. The transmission and distribution characteristics of the electromagnetic field of the torch configuration with two or three concentric tubes, as well as the metal spacer between inner and intermediate tubes with different depths were simulated with electromagnetic simulation software and verified by experiments. The results indicate that the inner tube of MPT plays an important role in strengthening the electric field intensity at the opening end of the MPT and redistributing the electromagnetic field in the whole torch by forming a double resonance configuration, and contributes to enhancing the macroscopic stability and the self-sustainment of the plasma. The stability of the plasma is proved to be excellent when the metal spacer between the inner and intermediate tubes is located at a place 20—30 mm away from the top opening of the torch. A proper location of the spacer can also avoid the formation of a static filament plasma or a rotating plasma rooted from the outer wall of the inner tube. With the help of morphological analysis, the underlying reason why MPT possesses a great tolerance to wet aerosols and air introduction was clearly made, that is, the formation region of the plasma formed with MPT is apparently separated from the reaction zone of it. 相似文献
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13.
在线标准加入法在微波等离子体炬原子发射光谱法中的应用 总被引:7,自引:2,他引:7
在线标准加入法在微波等离子体炬原子发射光谱法中的应用叶冬梅,张寒琦,于惊雷,金钦汉(吉林大学化学系,长春,130023)关键词在线标准加入法,微波等离子体炬,原子发射光谱法微波等离子体炬(MPT)是新发展起来的激发光源[1,2],由于它具有利于样品引... 相似文献
14.
Wenxia Pan Wenhong Zhang Wei Ma Chengkang Wu 《Plasma Chemistry and Plasma Processing》2002,22(2):271-283
Argon DC plasma jets in stable laminar flow were generated at atmospheric pressure with a specially designed torch under carefully balanced generating conditions. Compared with turbulent jets of short length with expanded radial appearance and high working noise, the laminar jet could be 550 mm in length with almost unchanged diameter along the whole length and very low noise. At gas feeding rate of 120 cm3/s, the jet length increases with increasing arc current in the range of 70–200 A, and thermal efficiency decreases slightly at first and then leveled off. With increasing gas flow rate, thermal efficiency of the laminar jets increases and could reach about 40%, when the arc current is kept at 200 A. Gauge pressure distributions of the jets impinging on a flat plate were measured. The maximum gauge pressure value of a laminar jet at low gas feeding rate is much lower than that of a turbulent jet. The low pressure acting on the material surface is favorable for surface cladding of metals, whereas the high pressure associated with turbulent jets will break down the melt pool. 相似文献
15.
微波等离子体炬光源基本特性的研究 总被引:9,自引:2,他引:9
用计算机化断层扫描成象技术研究了微波等离子体炬(MPT)放电的发射轮廓,证明该光源具有良好的对称性,并有一个有利于样品引入的中央通道,最佳分析区在炬管上方5~10 mm,用激光Thomson散射和Rayleigh散射技术测定了ArMPT和HeMPT放电的电子温度、电子密度和气体温度,证明MPT放电的电子温度很高而气体温度较低,是一种非热光源。其中的高能电子处于过布居状态,具有很高的激发能力。 相似文献
16.
The ionization characteristics of the analytes in a low power Ar microwave plasma torch (MPT) was studied. The influence of forward microwave power, the flow rate of carrier gas and matrix element on the degree of ionization were observed. The axial profiles of the degree of the ionization of some elements were determined. The experimental results are very important for developing the new analytical source——microwave plasma torch (MPT). 相似文献
17.
Dielectric barrier discharge (DBD)-based plasma deposition at atmospheric pressure, using glycidyl methacrylate (GMA, methacrylic acid-[2,3-epoxy-propyl ester]) as a prototype precursor was investigated in order to evaluate the applicability of dielectric barrier discharges to obtain plasma polymers with a high degree of structural retention of the starting precursor. Using pulsed excitation of the discharge, up to about 90% of the epoxy groups of GMA can be retained in plasma polymers obtainableat deposition rates in the order of 3–5nm/s. Preliminary investigations of the mechanism of film formation under pulsed plasma conditions indicate that the reaction of intact monomer molecules withsurface radicals generated during the pulses play a prominent role. 相似文献
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19.
Three methods have been examined for evaluating the concentration of nitrogen atoms in the afterglow of a nonequilibrium, helium-stabilized, atmospheric pressure plasma. These are nitric oxide titration, absolute emission intensity of N2(B 3g) and temporal decay of the N2(B 3g) emission. To employ the second method, the rate constants for the recombination of N atoms into N2(B 3g), at different vibrational levels of the B state, were determined. The third newly developed method has three advantages over the other two techniques: (1) it can predict the N-atom density for the entire afterglow, (2) it does not require calibration of the N2(B 3g) emission intensity, and (3) it does not disturb the gas flow. According to these measurements, the atmospheric pressure plasma produced a high density of nitrogen atoms, exceeding 4.0×1015 cm–3 at the edge of the discharge for 10 Torr N2 in 745 Torr He at 375 K and 15.5 W/cm3. 相似文献
20.
The atmospheric pressure radiofrequency (RF) plasma polymerization of furan was carried out with the objective of synthesizing polyfuran thin film. The structure, compositions and morphology of the plasma deposited polyfuran film were investigated by Fourier transform infrared (FTIR), atomic force microscopy (AFM), ultraviolet‐visible absorption spectroscopy (UV‐vis) and thermogravimetric analysis (TGA). The formation of polyfuran was confirmed using FTIR and UV‐visible analysis. The properties of plasma‐deposited polyfuran were compared with those of chemically synthesized polyfuran. Although the plasma deposited thin film polyfuran shows lower thermal stability than that of chemically synthesized polyfuran. It has better solubility in CHCl3, also. Thin uniform polyfuran films are obtained in plasma assisted polyfuran deposition, while particles are obtained in chemical polyfuran polymerization. 相似文献