Chemical catalysis with rf power mechanisms, systems and costs

Reid, Don

doi:10.1163/156856794x00117

Cited by 5 publications

(3 citation statements)

References 1 publication

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“…Dielectric properties are usually strongly dependent on temperature and frequency. For example, in the case of water, data published in the literature show that there was a change of 1 order of magnitude in the dielectric constant value as the frequency and temperature were changed by 5 and 2 orders of magnitude, respectively . The dielectric constant values used were measured at different frequencies, but if there was any effect on the product distribution and activity due to the presence of the dielectric material in the plasma zone, it would have been noticeable within the range of dielectric values of the materials that we used (4 orders of magnitude).…”

Section: Discussionmentioning

confidence: 99%

Effect of Dielectric Constant, Cavities in Series, and Cavities in Parallel on the Product Distribution of the Oligomerization of Methane via Microwave Plasmas

et al. 1996

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The use of microwave-induced plasmas as a method to oligomerize methane to higher hydrocarbons has been studied. The pressure range used was 10−20 Torr and the applied power was 60 W. The microwave power is coupled to the plasma by means of either an Evenson or a Beenakker cavity, the Beenakker being the most effective. We explored the effect of the presence of a dielectric material on the product distribution for this reaction. The values of the dielectric constants for these materials varied from 2.6 for Pb(Ac)2 to 10 000 for MnO2 relative to the vacuum. No direct correlation was found, but in some cases the selectivities toward C6s to C8s were enhanced. TiO2 and Li2CO3 increased the selectivities toward C6s. SnO2 was the best for selectivities to C7s and C8s. When a coating of Si/SiC on the reactor walls was present in the plasma zone, the selectivities toward C6s and C7s increased with respect to both materials (Si and SiC) by themselves. We also studied the effect of cavities in series and cavities in parallel on the oligomerization of methane with and without dielectric material in between the cavities. When methane and iodine are activated separately and then recombined, it seems that the oligomerization of methane is enhanced toward higher hydrocarbons. We found that when a dielectric material is placed in between and when the distance between the two cavities in series is the largest, the oligomerization of methane toward high molecular weight hydrocarbons is maximized.

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Section: Discussionmentioning

confidence: 99%

Effect of Dielectric Constant, Cavities in Series, and Cavities in Parallel on the Product Distribution of the Oligomerization of Methane via Microwave Plasmas

et al. 1996

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“…12 Discharges are capable of activating gaseous species, and in certain cases, nonthermodynamic equilibrium can be attained during the selective activation of stable small molecules. 13 Various types of energy and radiation, such as microwave, [14][15][16] radio frequency, 17 and electricity, 1,[18][19][20][21][22][23][24] can be used to generate discharge. Mok and Ham, Kim et al, and Broer and Hammer 20,23,24 investigated NO conversion using a pulse discharge in the first two cases and nonthermal plasma in the latter.…”

Section: Introductionmentioning

confidence: 99%

Direct Decomposition of NO Activated by Microwave Discharge

Tang

Zhang

et al. 2003

Ind. Eng. Chem. Res.

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The environmentally friendly removal of NO has been investigated using continuous microwave discharge (CMD) at atmospheric pressure. In these experiments, conversions of NO to N 2 as well as NO 2 were mainly observed for both dry and wet feed gas, which showed a great difference from those observed with other discharge methods. The effects of a series of reaction parameters, including microwave input power, O 2 concentration, NO concentration, and gas flow rate, on the product distribution and energy efficiency were also studied. Under all reaction conditions, the conversions of NO to N 2 were higher than those to NO 2 . The highest conversion of NO to N 2 was 88%. The reaction rate of NO removal and the effects of the different discharge modes on NO conversion and product distribution are also discussed. Through comparison of the results of different discharge modes, it was found that the addition of CH 4 apparently increased the conversion of NO to N 2 as well as the energy efficiency. A possible reaction process is suggested.

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“…Cold plasmas can be used to activate gaseous species and, in certain cases, nonthermodynamic equilibria can be obtained to selectively activate stable small molecules . Various types of energy and radiation can be used such as microwaves, , radio frequency, and electricity , to generate such plasmas. A limited number of studies in microwave and radio frequency catalysis are available due to problems associated with low yields from use of low pressure, mass transfer limitations, deactivation via formation of coke, or deposition on electrodes, and high operational costs.…”

Section: Introductionmentioning

confidence: 99%

Efficient Catalytic Plasma Activation of CO₂, NO, and H₂O

et al. 1998

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The activation of small molecules, such as CO 2 , NO, and H 2 O, has been achieved at atmospheric pressure via ac glow discharge methods in the presence of metal catalysts coated onto the electrode surfaces. A fan-type reactor having one rotating and one static electrode has been designed to diminish mass transfer effects. Time lapse photography of the emitting plasma intermediate species and optical emission studies have been used to monitor reaction pathways. Gas chromatography, mass spectrometry, and combined GC-MS methods have been used to monitor product distributions, selectivities, and activities. The effects of flow rate, input voltage, diluent gases, and metal coating have been systematically studied. Additionally, the mechanisms of CO 2 decomposition and the role of the metal catalyst in that decomposition have been studied by optical emission spectroscopy.

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Chemical catalysis with rf power mechanisms, systems and costs

Cited by 5 publications

References 1 publication

Effect of Dielectric Constant, Cavities in Series, and Cavities in Parallel on the Product Distribution of the Oligomerization of Methane via Microwave Plasmas

Effect of Dielectric Constant, Cavities in Series, and Cavities in Parallel on the Product Distribution of the Oligomerization of Methane via Microwave Plasmas

Direct Decomposition of NO Activated by Microwave Discharge

Efficient Catalytic Plasma Activation of CO₂, NO, and H₂O

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Chemical catalysis with rf power mechanisms, systems and costs

Cited by 5 publications

References 1 publication

Effect of Dielectric Constant, Cavities in Series, and Cavities in Parallel on the Product Distribution of the Oligomerization of Methane via Microwave Plasmas

Effect of Dielectric Constant, Cavities in Series, and Cavities in Parallel on the Product Distribution of the Oligomerization of Methane via Microwave Plasmas

Direct Decomposition of NO Activated by Microwave Discharge

Efficient Catalytic Plasma Activation of CO2, NO, and H2O

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Efficient Catalytic Plasma Activation of CO₂, NO, and H₂O