Electrical corona

Non-thermal plasmas can be produced in a number of ways, including a variety of electrical corona discharges, radio frequency discharges, microwave discharges and electron beams. The most common NTP technologies for emission reduction in engine exhaust streams are the following. 

In atmospheric pressure chemical ionization, heat and a coaxial flow of N2 convert eluate into a fine mist from which solvent and analyte evaporate (Figure 22-19). Like chemical ionization in the ion source of a mass spectrometer, atmospheric pressure chemical ionization creates new ions from gas-phase reactions between ions and molecules. The distinguishing feature of this technique is that a high voltage is applied to a metal needle in the path of the aerosol. An electric corona (a plasma containing charged particles) forms around the needle,... 

Electrical corona discharge may be carried out in air or in other gases. For plastics based on olefins the best results are obtained in dry air but in treating nylon greater success was reported with discharge in a nitrogen environment. 

Loeb, L.B., in Electrical Coronas, University of California. Berkeley, Calif., 1965. 

Loeb, L. B., Electrical Coronas, Univ. of Calif. Press, 1965. 

Historical Review of the Chemical Application of Electrical Corona Discharges... 

The general reaction pathways of NOjt in a plasma reactor arc summarized in Fig 8. The dominant removal pathway of NOjc in the gas-phase homogeneous reactions is oxidation than reduction for both electrical corona discharge and elec iron-beam, especially when the oxygen content is higher than around 3-4% [78. 88-90]. Oxidation of NO occurs mostly by ozone (R4) and peroxy radicals (R5, R6) in the presence of hydrocarbons. Some of NOj arc converted to NO by back reactions by UV (R2) and O radical. 

In stead of the corona-induced plasma, microwave can also activate catalysts such as silica and Cu/ZSM-5 [146], zeolite [147]. However, the microwave-induced plasmas arc usually operated at around several tens to several hundred kJ/L, which are 2-3 orders of magnitude higher SIE values then the electrical corona plasmas. Due to the intrinsic diBlculty and the complexity of the PDC system, its progress seems to be slow compared to the PE-SCR at present stage. 

Locb, L. B. (1965) Electrical coronas Their basic physical mechanisms Los Angeles, University of California Press... 

A violet spot at the needle tip during an online sheathless CE/MS experiment indicates electrical (Corona) discharge, which is prone to occur in particular under sheathless unpressurized reverse polarity CE/MS. If such an event occurs, the ESI and the counterelectrode voltages are to be stepwise decreased. 

Pure ozone for ozonolysis of OA was generated from pure carbon dioxide by electric corona-discharge treatment, thus offering an industrially affordable process [65]. 

Electrical ( corona ) discharge treatment of polyethylene and polypropylene film has been used for many years in order to render these surfaces printable and suitable for lamination or coating. In this process the polymer film is passed over a grounded metal roller covered with a "dielectric" (insulating) material. Separated from the film by mm is an electrode bar to which a high voltage is applied (typically 15 kV at 20 K Hz). Air in the film-electrode gap is ionised, the corona discharge thus formed is stable and this "treats" the film surface. 

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