Integrated non-thermal plasma reactor-diesel particulate filter

Abstract

An integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus 10 comprises a wall flow-type substrate 12 including a plurality of alternating high voltage 20 and ground electrode layers 22 and filter layers 24 disposed between said high voltage 20 and ground electrode layers 22 . Channels 34 extending through the electrode layers 20, 22 are plugged to prevent exhaust flow. A portion of the exhaust channels 18 extending through the filter layers 23 are plugged 26 such that each channel 18 is plugged only at one end 14 or 16 . During operation, a plasma is generated in the filter layers 24 . An exhaust stream 28 is passed through the filter channels 18 and nitrogen oxides in the exhaust stream 28 are converted in the plasma primarily to NO 2 while particulate matter in the exhaust stream 28 is captured in the porous channel walls 19 . The filter 24 is continuously regenerated by NO 2 formed in the plasma. NO byproduct from the filter regeneration is converted back into NO 2 via plasma.

1 . An integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  10  comprising: 
 a wall flow-type substrate  12  having an exhaust inlet  14 , an exhaust outlet  16 , and a plurality of parallel exhaust channels  18  extending through said substrate  12 ;  
 said substrate  12  having a plurality of layers arranged in an alternating fashion comprising a high voltage electrode layer  20 ; a ground electrode layer  22 ; and a filter layer  24  disposed between said high voltage electrode layer  20  and said ground electrode layer  22 ;  
 electrode layer channels  30  extending through said high voltage electrode layers  20  and said ground electrode layers  22  being plugged to prevent exhaust flow therein; and  
 a portion of said parallel channels  18  at exhaust inlet end  14  and exhaust outlet  16  being plugged  26  in an arrangement wherein each channel  18  is plugged only at one end;  
 wherein during operation of said apparatus  10 , a plasma is generated in said filter layers  24  and an exhaust stream  28  to be treated enters at said inlet  14 , flows through said filter channels  18  and through porous channel walls  19 , and exits at said outlet  16  as a treated exhaust stream  50 ; nitrogen oxides in said exhaust stream  28  being converted in said plasma primarily to NO 2 ; particulate matter in said exhaust stream  28  being captured in said porous channel walls  19 ; said filter layers  24  being continuously regenerated by said plasma and by said NO 2  formed in said plasma; and NO byproduct from said filter generation being converted back into NO 2  via plasma at said outlet ends  16  of said exhaust channels  18 .  
 
     
     
         2 . The apparatus  10  of  claim 1 , wherein said wall flow substrate  12  is made of cordierite.  
     
     
         3 . The apparatus  10  of  claim 1 , wherein alternating channels  26  in said filter layers  24  are plugged to provide a checkered-type pattern of plugged channels  26  and unplugged exhaust channels  18 .  
     
     
         4 . The apparatus  10  of  claim 1 , wherein said exhaust stream  28  to be treated comprises an exhaust stream from a coal fired furnace, an oil fired furnace, a reciprocating internal combustion engine, a gasoline spark ignition engine, a diesel engine, or a gas turbine engine.  
     
     
         5 . The apparatus  10  of  claim 1 , wherein said exhaust stream to be treated  28  comprises a diesel engine exhaust stream.  
     
     
         6 . The apparatus of  claim 1 , comprising: 
 high voltage electrode layers  66  and said ground electrode layers  68  comprising dielectric barrier electrode layers  62  to provide an integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  60 .    
     
     
         7 . A combustion exhaust treatment system  44  comprising: 
 the integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  10  of  claim 1 , said apparatus  10  being in fluid communication with an exhaust outlet  48  of a combustion device  46 ;  
 a short pulse power source  42  connected to said integrated nonthermal plasma reactor-diesel particulate filter apparatus  10  and  
 a catalytic converter  52  having a catalyst for reducing nitrogen oxides in an exhaust stream, said catalytic converter  52  having an inlet  54  connected to said integrated non-thermal plasma reactor-diesel particulate filter apparatus  10  for receiving a plasma and particulate treated exhaust stream  50  and an outlet  56  for emitting a catalyst treated exhaust stream  58 .  
 
     
     
         8 . A combustion exhaust treatment system  70  comprising: 
 the integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  10  of  claim 1 , having high voltage electrode layers  66  and ground electrode layers  68  comprising dielectric barrier electrode layers  62  to provide an integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  60 , said apparatus  60  being in fluid communication with an exhaust outlet  48  of a combustion device  46 ;  
 an alternating current power source  72  connected to said integrated non-thermal plasma reactor-diesel particulate filter apparatus  60 ; and  
 a catalytic converter  52  having a catalyst for reducing nitrogen oxides in an exhaust stream, said catalytic converter  52  having an inlet  54  connected to said integrated non-thermal plasma reactor-diesel particulate filter apparatus  60  for receiving a plasma and particulate treated exhaust stream  50  and an outlet  56  for emitting a catalyst treated exhaust stream  58 .  
 
     
     
         9 . A method for treating particulate matter and nitrogen oxides in a combustion exhaust stream  28  comprising: 
 passing a combustion exhaust stream  28  through an integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  10  comprising:  
 a wall flow-type substrate  12  having an exhaust inlet  14 , an exhaust outlet  16 , and a plurality of parallel exhaust channels  18  extending through said substrate  12 ;  
 said substrate  12  having a plurality of layers arranged in an alternating fashion comprising a high voltage electrode layer  20 ; a ground electrode layer  22 ; and a filter layer  24  disposed between said high voltage electrode layer  20  and said ground electrode  22 ;  
 electrode layer channels  34  extending through said high voltage electrode layers  20  and said ground electrode layers  22  being plugged to prevent exhaust flow therein; and  
 a portion of said exhaust channels  18  at said exhaust inlet  14  and said exhaust outlet  16  being plugged in an arrangement wherein each exhaust channel  18  is plugged only at one end;  
 generating a plasma in said filter layers  24  of said apparatus  10  wherein said exhaust stream  28  to be treated enters at said inlet  14 , flows through said exhaust channels  18  and through porous channels walls  19 , and exits at said outlet  16  as a plasma and particulate treated exhaust stream  50 ;  
 whereby nitrogen oxides in said exhaust stream  28  are converted in said plasma primarily to NO 2 ; particulate matter in said exhaust stream  28  is captured in said porous channel walls  19 ; and said filter layers  24  are continuously regenerated by said plasma and by said NO 2  formed in said plasma; and NO byproduct from said filter generation are converted back into NO 2  via plasma primarily at said outlet ends  16  of said exhaust channels  18 .  
 
     
     
         10 . The method of  claim 9 , wherein said wall flow substrate  12  is made of cordierite.  
     
     
         11 . The method of  claim 9 , wherein alternating exhaust channels  18  in said filter layers  24  are plugged to provide a checkered-type pattern of plugged channels  26  and unplugged exhaust channels  18 .  
     
     
         12 . The method of  claim 9 , wherein said exhaust stream  28  to be treated comprises an exhaust stream from a coal fired furnace, an oil fired furnace, a reciprocating internal combustion engine, a gasoline spark ignition engine, a diesel engine, or a gas turbine engine.  
     
     
         13 . The method of  claim 9 , wherein said exhaust stream to be treated  28  comprises a diesel engine exhaust stream.  
     
     
         14 . The method of  claim 9 , further comprising: 
 further treating said plasma and particulate treated exhaust stream  50  in a catalytic converter  52  having a catalyst for reducing nitrogen oxides in an exhaust stream;    said catalytic converter  52  having an inlet  54  connected to said integrated non-thermal plasma reactor-diesel particulate filter apparatus  10  for receiving said plasma and particulate treated exhaust stream  50  and an outlet  56  for emitting a catalyst treated exhaust stream  56 .    
     
     
         15 . The method of  claim 9 , wherein said integrated nonthermal plasma reactor-diesel particulate filter exhaust treatment apparatus  10  comprising is powered by a short pulse power supply  42 .  
     
     
         16 . The method of  claim 9 , wherein said high voltage electrode layers  66  and said ground electrode layers  65  comprise dielectric barrier electrode layers  62  providing an integrated non-thermal plasma reactor-diesel particulate filter  60 .  
     
     
         17 . The method of  claim 9 , wherein said high voltage electrode layers  66  and said ground electrode layers  65  comprise dielectric barrier electrode layers  62  providing an integrated non-thermal plasma reactor-diesel particulate filter  60 ; and 
 wherein said integrated non-thermal plasma reactor-diesel particulate filter exhaust treatment apparatus  60  is powered by an alternating current power supply  72 .