Nitrogen oxide removal catalyst system and nitrogen oxide removal method
AssigneesTokyo Roki Co., Ltd., Nissan Diesel Motor Co., Ltd.
InventorsTakayuki Mori, Nobuya Iwami, Takayuki Kumagai, Isamu Kanaya, Hiroki Ueno, Kiminobu Hirata
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Abstract
Provided in a catalyst system are: a first reaction part fitted with a first catalyst containing, as active constituents, at least, a complex oxide consisting of two or more oxides selected from among silica, alumina, titania, zirconia, and tungsten oxide, and a rare earth metal or transition metal (except Cu, Co, Ni, Mn, Cr, and V); and a second reaction part fitted with a second catalyst containing, as active constituents, at least, a noble metal and a silica-alumina type complex oxide.
Claims10
A nitrogen oxide removal catalyst system, comprising a first reaction part for denitrating nitrogen oxides by reacting said nitrogen oxide with ammonia, being provided with a first catalyst containing, as active constituents, at least:
- a complex oxide comprising two or more oxides selected from silica, alumina, titania, zirconia, and tungsten oxide;
- a rare earth metal or a transition metal (except Cu, Co, Ni, Mn, Cr, and V);
- and sulfur or phosphorus;
- and
- a second reaction part for oxidatively decomposing ammonia that has leaked from the first reaction part, being provided with a second catalyst containing, as active constituents, at least:
- a noble metal and a silica-alumina type complex oxide.
A nitrogen oxide removal method comprising denitrating nitrogen oxides reductively by contacting the nitrogen oxides with a first catalyst in the presence of ammonia, the first catalyst containing, as active constituents, at least:
- a complex oxide comprising two or more oxides selected from silica, alumina, titania, zirconia, and tungsten oxide;
- and a rare earth metal or transition metal (except Cu, Co, Ni, Mn, Cr, and V);
- and sulfur or phosphorus;
- and
- decomposing unreacted ammonia oxidatively by contacting the untreated ammonia with a second catalyst, the second catalyst containing, as active constituents, at least, a noble metal and a silica-alumina type complex oxide.
Dependencies are inferred from the claim text.