Apparatus and method for treating exhaust gas and pulse generator used therefor

• US 6,274,006 B1
• Filed: 08/09/1999
• Issued: 08/14/2001
• Est. Priority Date: 04/04/1996
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Kawamura, Keisuke, Shigemizu, Tetsuro, Murata, Masayoshi, Yoshida, Hirohisa
• Primary Examiner(s): Mayekar, Kishor
• Application Number:
  US09/369,843
• Time in Patent Office: 736 Days
• Field of Search: 204/164-179, 422/186-186, 422/906, 422/907
• US Class Current: 204/164
• CPC Class Codes: B01D 2259/818 Employing electrical discharges or the generation of a plasma
• CPC Class Codes: B01D 53/32 by electrical effects other than those provided for in group B01D61/00
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: B01J 2219/0807 involving electrodes
• CPC Class Codes: B01J 2219/0875 Gas
• CPC Class Codes: B01J 2219/0894 Processes carried out in the presence of a plasma
• CPC Class Codes: F01N 3/0892 Electric or magnetic treatment, e.g. dissociation of noxious components electric filters F01N3/01; regeneration of exhaust filters F01N3/023; heating catalytic converters F01N3/2006

Abstract

An apparatus and method for treating exhaust gases. A plurality of stages of reactor chambers are connected in series in the direction of an exhaust gas flow. High-voltage power supplies are connected to the reactor chambers In each of these reactor chambers, a streamer discharger plasma is generated. The more downstream a reactor chamber of a stage is placed, the lower energy to be cast into the reactor chamber becomes. The density of electrons generated in a gas decomposition unit is higher on the upstream side of the exhaust gas flow and the electron density is lower on the downstream side. A pulse generator is provided in which a high voltage, which is an output voltage of a D.C. charger (V₀), is simultaneously applied to a plurality of distributed constant lines, which are connected in parallel with one another, by a signal shortcircuit switch (S₁).

Claims

1. A method of treating exhaust gas, comprising detoxifying a toxic component contained in said exhaust gas by supplying energy to a reactor chamber to thereby generate a streamer discharge plasma, and then flowing the exhaust gas through said reactor chamber to thereby decompose the toxic component,

wherein said method comprises preliminarily connecting a plurality of stages of reactor chambers in series in a direction in which an exhaust gas flows;

and setting energy to be supplied to each of said reactor chambers in such a manner that as a reactor chamber to be supplied with energy becomes closer to a most downstream reactor chamber, energy to be supplied thereto is gradually decreased.

2. The method according to claim 1, wherein, in the step of preliminarily connecting a plurality of stages of reactor chambers, the plurality of stages of reactor chambers are connected in a meander pattern or are coaxially arranged.