Reactors, electrical discharge

The carbon black (soot) produced in the partial combustion and electrical discharge processes is of rather small particle si2e and contains substantial amounts of higher (mostly aromatic) hydrocarbons which may render it hydrophobic, sticky, and difficult to remove by filtration. Electrostatic units, combined with water scmbbers, moving coke beds, and bag filters, are used for the removal of soot. The recovery is illustrated by the BASF separation and purification system (23). The bulk of the carbon in the reactor effluent is removed by a water scmbber (quencher). Residual carbon clean-up is by electrostatic filtering in the case of methane feedstock, and by coke particles if the feed is naphtha. Carbon in the quench water is concentrated by flotation, then burned. 

These types of corona reactors involve simultaneous application of non-thermal plasma above liquid surface and direct high voltage electrical discharge in liquid phase. That is achieved by the combination of different electrode... 

Grymonpre, DR Finney, WC Clark, RJ Locke BR. Hybrid gas-liquid electrical discharge reactors for organic compound degradation. Industrial and Engineering Chemistry Research, 2004 43,1975-1989. 

Lukes, P Appleton, AT Locke, BR. Hydrogen peroxide and ozone formation in hybrid gas-liquid electrical discharge reactors. IEEE Trans. Industrial. Applications, 2004 40 (1), 60-67. 

Petemel, I Kusic, H Koprivanac, N Locke, BR. The roles of ozone and zeolite on reactive dye degradation in electrical discharge reactors. Environmental Technology, 2006 27 (5) 545-558. 

Water or waste water ozonation - regardless of the scale of equipment - is mostly performed in directly gassed systems, where the ozone containing gas is produced by an electrical discharge ozone generator and is introduced into the reactor by some type of gas diffuser. Since two phases, the gas and the liquid, are required for the oxidation reaction to proceed as it does, they are also called heterogeneous systems. 

Although, as was discussed above, plasma and other discharges are usually discussed in the context of gas-phase processes, electrical discharges are also quite well studied in liquids. For example, liquid-phase discharge reactors have recently been applied in drinking water and... 

Liquid-phase carbonization occurs for some precursors, such as pitches, which become viscous fluids before carbonization. This process has been used to produce various polycrystalline graphite blocks for steel refining and electrical discharge machining, jigs for the growth of semiconductor crystals, structural components of nuclear reactor, etc. 

There are numerous modifications which can be made to the basic reactor design. The initial dissociation of the silane gas can be by ultraviolet (UV) light illumination (photo-CVD), which either excites the silane directly, or by energy transfer from mercury vapour introduced into the chamber. Photo-CVD reactors eliminate the electric discharge and prevent the bombardment of the growing film by ions from the plasma, which may be a source of defects. A different way of reducing bombardment is to separate the plasma from the growing... 

Kistiakowsky and Volpi, using a stirred flow reactor, added N atoms (produced in an electric discharge) to nitrous oxide at 553 °K and estimated ki63 10 I.moIe sec for the reaction... 

Passage of PHj, PHj-SiH or PHj-GeH through a silent electric discharge or hot-tube pyrolysis reactor results in complex product mixtures, which involve formation of new P—H bonds. Major products from PHj, PHj-SiH, or PHj-GeH reactions include P2H > SiHjPHj and GeHjPHj, in addition to Si H and GCjH. Lesser products include SijHjPH, (SiHjj PH, SijH, Si, H,o, (GeHjj PH, and GCjHj. 

The production of acetylene from natural gas has been studied in a 60 Hz electrical discharge at atmospheric pressure38. The apparatus consisted of a cyclone-type reactor in which the products could be removed through a hollow electrode. 

Most of the studies have been made employing the ion source of a mass spectrometer as a reactor and this review necessarily emphasizes this aspect of the subject. Several studies of ion-molecule reactions in electric discharges have appeared in recent years and these are reviewed briefly. 

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