Exhaust gas processing method and exhaust gas processing system

Abstract

An exhaust gas processing method and an exhaust gas processing system for controlling the spatial density distribution of particulate matter in exhaust gas by utilizing corona discharge in exhaust gas containing floating particulate matter such as diesel engine exhaust gas to form a relatively particulate matter-rich area and a relatively particulate matter-lean area, and diving exhaust gas particulates to the former and the latter. An exhaust gas processing system ( 10 ) provided with a high-voltage electrode ( 12 ) and a low-voltage electrode ( 11 ), wherein exhaust gas G is allowed to flow between the facing high-voltage electrode ( 12 ) and low-voltage electrode ( 11 ), and a high voltage is applied to between the counter electrodes to generate corona discharge in the exhaust gas G, whereby floating particulate matter ( 20 ) in the exhaust gas G is charged, the spatial density distribution of the floating particulate matter in the exhaust gas is controlled by an electrostatic force between the counter electrodes, and the exhaust gas G is divided into a high-concentration exhaust gas Gb in the vicinity of the low-voltage electrode where a particulate matter concentration is relatively high and a low-concentration exhaust gas Ga in the vicinity of the high-voltage electrode where a particulate matter concentration is relatively low.

1 . An exhaust gas processing method, comprising a high-voltage electrode and a low-voltage electrode facing said high-voltage electrode, wherein exhaust gas flows through between the counter electrodes, a high voltage is applied between the counter electrodes to generate corona discharge in the exhaust gas, floating particulate matter in the exhaust gas non-uniformly distributes near the low-voltage electrode by electrification and coheres through the corona discharge, and the exhaust gas near the low-voltage electrode is divided into high-concentration exhaust gas in which the concentration of the floating particulate matter is relatively high and low-concentration exhaust gas in which the concentration of the floating particulate matter is relatively low.  
   
   
       2 . The exhaust gas processing method according to  claim 1 , comprising purifying the high-concentration exhaust gas with a filter.  
   
   
       3 . An exhaust gas processing system having a high-voltage electrode and a low-voltage electrode facing said high-voltage electrode, comprising: 
 an electrifying area in which exhaust gas flows through between the counter electrodes, a high voltage is applied between the counter electrodes to generate corona discharge in the exhaust gas, and the floating particulate matter is electrified,    a condensing area for non-uniformly distributing the floating particulate matter electrified by the electrifying area near the low-voltage electrode, and    a divide-flow area for dividing the exhaust gas near the low-voltage electrode in which the concentration of the floating particulate matter is relatively high, into high-concentration exhaust gas in which the concentration of the floating particulate matter is relatively high and low-concentration exhaust gas in which the concentration of the floating particulate matter is relatively low.    
   
   
       4 . The exhaust gas processing system according to  claim 3 , wherein 
 the low-voltage electrode is formed into a cylindrical body, the high-voltage electrode is provided in the longitudinal direction along near the center of the low-voltage electrode of the cylindrical body in the electrifying area in at least the upstream side of the low-voltage electrode, and an inner cylinder for dividing exhaust gas is provided inside the low-voltage electrode in the divide-flow area in at least the downstream side of the low-voltage electrode, so that the low-concentration exhaust gas flows through the inside of the inner cylinder and the high-concentration exhaust gas flows through the outside of the inner cylinder.    
   
   
       5 . The exhaust gas processing system according to  claim 3 , wherein 
 the low-voltage electrode is formed into a cylindrical body, the high-voltage electrode is provided in the longitudinal direction along near the center of the low-voltage electrode in the cylindrical body in the electrifying area in at least the upstream side of the low-voltage electrode, the low-voltage electrode is formed to be gas-permeable in the condensing area in the downstream side of the electrifying area, and an outer cylinder is provided outside the low-voltage electrode in the condensing area and the divide-flow area so that the exhaust gas flowing in from the upstream side of the low-voltage electrode is divided into the low-concentration exhaust gas flowing through the inside of the low-voltage electrode and the high-concentration exhaust gas flowing through the outside of the low-voltage electrode.    
   
   
       6 . The exhaust gas processing system according to any one of  claims 3  to  5 , comprising a filter for purifying floating particulate matter included in the high-concentration exhaust gas.  
   
   
       7 . The exhaust gas processing system according to any one of  claims 3  to  5 , wherein 
 the exhaust gas is exhaust gas of an internal combustion engine.