Exhaust gas conversion system and exhaust gas conversion method

Abstract

An exhaust gas conversion system includes an oxide catalyst, a filter, a selective catalytic reduction catalyst and an ammonia supplying device. The oxide catalyst, the filter and the selective catalytic reduction catalyst are sequentially arranged in a direction in which an exhaust gas flows in an exhaust path of a diesel engine. The ammonia supplying device is positioned between the oxide catalyst and the filter and configured to supply ammonia.

1 . An exhaust gas conversion system comprising:
 an oxide catalyst;   a filter;   a selective catalytic reduction catalyst, the oxide catalyst, the filter and the selective catalytic reduction catalyst being sequentially arranged in a direction in which an exhaust gas flows in an exhaust path of a diesel engine; and   an ammonia supplying device positioned between the oxide catalyst and the filter and configured to supply ammonia.   
     
     
         2 . The exhaust gas conversion system as claimed in  claim 1 , wherein the filter has a honeycomb structural body including a honeycomb unit having a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit,
 wherein the plurality of through holes are sealed on one end of the honeycomb unit in the longitudinal direction.   
     
     
         3 . The exhaust gas conversion system as claimed in  claim 2 , wherein the honeycomb unit does not support a catalyst. 
     
     
         4 . The exhaust gas conversion system as claimed in  claim 2 , wherein the honeycomb unit includes silicon carbide or silicon carbide bonded silicon. 
     
     
         5 . The exhaust gas conversion system as claimed in  claim 2 , wherein each of the partition walls of the honeycomb unit has a thickness of approximately 0.10 mm or more and approximately 0.18 mm or less. 
     
     
         6 . The exhaust gas conversion system as claimed in  claim 1 , wherein the selective catalytic reduction catalyst has a honeycomb structural body including a honeycomb unit having a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit,
 wherein the honeycomb unit includes zeolite and an inorganic binder.   
     
     
         7 . The exhaust gas conversion system as claimed in  claim 6 , wherein the honeycomb unit included in the selective catalytic reduction catalyst includes an inorganic fiber, a scale-like material, a tetrapod-shaped material, a three-dimensional needle-shaped material or a combination thereof. 
     
     
         8 . The exhaust gas conversion system as claimed in  claim 6 , wherein the zeolite includes a phosphate group zeolite. 
     
     
         9 . The exhaust gas conversion system as claimed in  claim 1 , wherein the filter and the selective catalytic reduction catalyst are installed in a metal container. 
     
     
         10 . The exhaust gas conversion system as claimed in  claim 1 , wherein the oxide catalyst is canned in a first metal container in a state where a first holding sealing member is provided at an outer peripheral part of the oxide catalyst, wherein the filter is canned in a second metal container in a state where a second holding sealing member is provided at an outer peripheral part of the filter, wherein the selective catalytic reduction catalyst is canned in a third metal container in a state where a third holding sealing member is provided at an outer peripheral part of the selective catalytic reduction catalyst. 
     
     
         11 . The exhaust gas conversion system as claimed in  claim 1 , wherein the ammonia supplying device is an injection nozzle to inject ammonia or a compound that generates ammonia by being decomposed. 
     
     
         12 . The exhaust gas conversion system as claimed in  claim 11 , wherein the compound that generates ammonia by being decomposed is urea water. 
     
     
         13 . The exhaust gas conversion system as claimed in  claim 1 , wherein the oxide catalyst has a honeycomb structural body including a honeycomb unit that supports a catalyst and has a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit. 
     
     
         14 . The exhaust gas conversion system as claimed in  claim 13 , wherein a material constituting the honeycomb unit is cordierite. 
     
     
         15 . The exhaust gas conversion system as claimed in  claim 2 , wherein a material constituting the honeycomb unit included in the filter is silicon carbide, silicon carbide bonded silicon, cordierite, or aluminum titanate. 
     
     
         16 . The exhaust gas conversion system as claimed in  claim 6 , wherein the selective catalytic reduction catalyst has a single honeycomb unit. 
     
     
         17 . The exhaust gas conversion system as claimed in  claim 6 , wherein the zeolite is a β type zeolite, a ZSM-5 type zeolite, or a phosphate group zeolite. 
     
     
         18 . The exhaust gas conversion system as claimed in  claim 1 , wherein the phosphate group zeolite is a SAPO (silico aluminophosphate), a MeAPO (metal aluminophosphate), or a MeAPSO (metallo-aluminosilicophospate). 
     
     
         19 . The exhaust gas conversion system as claimed in  claim 18 , wherein the SAPO is SAPO-5, SAPO-11 or SAPO-34. 
     
     
         20 . The exhaust gas conversion system as claimed in  claim 1 , wherein the zeolite is obtained by ion-exchange with copper, iron or a combination of copper and iron. 
     
     
         21 . The exhaust gas conversion system as claimed in  claim 6 , wherein the selective catalytic reduction catalyst has a plurality of the honeycomb units and each of the plurality of the honeycomb units is adhered to each other by interposing an adhesive layer. 
     
     
         22 . The exhaust gas conversion system as claimed in  claim 21 , wherein each of the plurality of honeycomb units has a cross-section perpendicular to the longitudinal direction of the honeycomb unit that is substantially a fan-shape having a central angle of approximately 90°. 
     
     
         23 . The exhaust gas conversion system as claimed in  claim 1 , wherein the selective catalytic reduction catalyst has a honeycomb structural body including a honeycomb unit that supports a zeolite and has a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit. 
     
     
         24 . The exhaust gas conversion system as claimed in  claim 23 , wherein a material constituting the honeycomb unit is cordierite. 
     
     
         25 . The exhaust gas conversion system as claimed in  claim 24 , wherein the zeolite is a β type zeolite, a ZSM-5 type zeolite, or a phosphate group zeolite. 
     
     
         26 . The exhaust gas conversion system as claimed in  claim 25 , wherein the phosphate group zeolite is a SAPO (silico aluminophosphate), a MeAPO (metal aluminophosphate), or a MeAPSO (metallo-aluminosilicophospate). 
     
     
         27 . The exhaust gas conversion system as claimed in  claim 26 , wherein the SAPO is SAPO-5, SAPO-11 or SAPO-34. 
     
     
         28 . The exhaust gas conversion system as claimed in  claim 23 , wherein the zeolite is obtained by ion-exchange with copper, iron or a combination of copper and iron. 
     
     
         29 . The exhaust gas conversion system as claimed in  claim 9 , wherein the filter is canned in a first metal container in a state where a first holding sealing member is provided at an outer peripheral part of the filter, wherein the selective catalytic reduction catalyst is canned in a second metal container in a state where a second holding sealing member is provided at an outer peripheral part of the selective catalytic reduction catalyst. 
     
     
         30 . An exhaust gas conversion method comprising:
 converting an exhaust gas by using the exhaust gas conversion system claimed in  claim 1 .   
     
     
         31 . The exhaust gas conversion method as claimed in  claim 30 , wherein the filter has a honeycomb structural body including a honeycomb unit having a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit,
 wherein the plurality of through holes are sealed on one end of the honeycomb unit in the longitudinal direction.   
     
     
         32 . The exhaust gas conversion method as claimed in  claim 31 , wherein the honeycomb unit does not support a catalyst. 
     
     
         33 . The exhaust gas conversion method as claimed in  claim 31 , wherein the honeycomb unit includes silicon carbide or silicon carbide bonded silicon. 
     
     
         34 . The exhaust gas conversion method as claimed in  claim 31 , wherein each of the partition walls of the honeycomb unit has a thickness of approximately 0.10 mm or more and approximately 0.18 mm or less. 
     
     
         35 . The exhaust gas conversion method as claimed in  claim 30 , wherein the selective catalytic reduction catalyst has a honeycomb structural body including a honeycomb unit having a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit,
 wherein the honeycomb unit includes zeolite and an inorganic binder.   
     
     
         36 . The exhaust gas conversion method as claimed in  claim 35 , wherein the honeycomb unit included in the selective catalytic reduction catalyst includes an inorganic fiber, a scale-like material, a tetrapod-shaped material, a three-dimensional needle-shaped material or a combination thereof. 
     
     
         37 . The exhaust gas conversion method as claimed in  claim 35 , wherein the zeolite includes a phosphate group zeolite. 
     
     
         38 . The exhaust gas conversion method as claimed in  claim 30 , wherein the filter and the selective catalytic reduction catalyst are installed in a metal container. 
     
     
         39 . The exhaust gas conversion method as claimed in  claim 30 , wherein the oxide catalyst is canned in a first metal container in a state where a first holding sealing member is provided at an outer peripheral part of the oxide catalyst, wherein the filter is canned in a second metal container in a state where a second holding sealing member is provided at an outer peripheral part of the filter, wherein the selective catalytic reduction catalyst is canned in a third metal container in a state where a third holding sealing member is provided at an outer peripheral part of the selective catalytic reduction catalyst. 
     
     
         40 . The exhaust gas conversion method as claimed in  claim 30 , wherein the ammonia supplying device is an injection nozzle to inject ammonia or a compound that generates ammonia by being decomposed. 
     
     
         41 . The exhaust gas conversion method as claimed in  claim 40 , wherein the compound that generates ammonia by being decomposed is urea water. 
     
     
         42 . The exhaust gas conversion method as claimed in  claim 30 , wherein the oxide catalyst has a honeycomb structural body including a honeycomb unit that supports a catalyst and has a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit. 
     
     
         43 . The exhaust gas conversion method as claimed in  claim 42 , wherein the material constituting the honeycomb unit is cordierite. 
     
     
         44 . The exhaust gas conversion method as claimed in  claim 31 , wherein the material constituting the honeycomb unit included in the filter is silicon carbide, silicon carbide bonded silicon, cordierite, or aluminum titanate. 
     
     
         45 . The exhaust gas conversion method as claimed in  claim 35 , wherein the selective catalytic reduction catalyst has a single honeycomb unit. 
     
     
         46 . The exhaust gas conversion method as claimed in  claim 35 , wherein the zeolite is a β type zeolite, a ZSM-5 type zeolite, or a phosphate group zeolite. 
     
     
         47 . The exhaust gas conversion method as claimed in  claim 37 , wherein the phosphate group zeolite is a SAPO (silico aluminophosphate), a MeAPO (metal aluminophosphate), or a MeAPSO (metallo-aluminosilicophospate). 
     
     
         48 . The exhaust gas conversion method as claimed in  claim 47 , wherein the SAPO is SAPO-5, SAPO-11 or SAPO-34. 
     
     
         49 . The exhaust gas conversion method as claimed in  claim 30 , wherein the zeolite is obtained by ion-exchange with copper, iron, or a combination of copper and iron. 
     
     
         50 . The exhaust gas conversion method as claimed in  claim 35 , wherein the selective catalytic reduction catalyst has a plurality of the honeycomb units and each of the plurality of honeycomb units is adhered to each other by interposing an adhesive layer. 
     
     
         51 . The exhaust gas conversion method as claimed in  claim 50 , wherein each of the plural honeycomb units has a cross-section perpendicular to the longitudinal direction of the honeycomb unit that is substantially a fan-shape having a central angle of approximately 90°. 
     
     
         52 . The exhaust gas conversion method as claimed in  claim 30 , wherein the selective catalytic reduction catalyst has a honeycomb structural body including a honeycomb unit that supports a zeolite and has a plurality of through holes divided by partition walls and arranged in a longitudinal direction of the honeycomb unit. 
     
     
         53 . The exhaust gas conversion method as claimed in  claim 52 , wherein the material constituting the honeycomb unit is cordierite. 
     
     
         54 . The exhaust gas conversion method as claimed in  claim 53 , wherein the zeolite is a β type zeolite, a ZSM-5 type zeolite, or a phosphate group zeolite. 
     
     
         55 . The exhaust gas conversion method as claimed in  claim 54 , wherein the phosphate group zeolite is a SAPO (silico aluminophosphate), a MeAPO (metal aluminophosphate), or a MeAPSO (metallo-aluminosilicophospate). 
     
     
         56 . The exhaust gas conversion method as claimed in  claim 55 , wherein the SAPO is SAPO-5, SAPO-11 or SAPO-34. 
     
     
         57 . The exhaust gas conversion method as claimed in  claim 52 , wherein the zeolite is obtained by ion-exchange with copper, iron, or a combination of copper and iron. 
     
     
         58 . The exhaust gas conversion method as claimed in  claim 39 , wherein the filter is canned in a first metal container in a state where a first holding sealing member is provided at an outer peripheral part of the filter, wherein the selective catalytic reduction catalyst is canned in a second metal container in a state where a second holding sealing member is provided at an outer peripheral part of the selective catalytic reduction catalyst.