Exhaust gas purifier

Patent metadata

Field	Value
Publication number	US-9480948-B2
Application number	US-201314396234-A
Country	US
Kind code	B2
Filing date	Apr 9, 2013
Priority date	May 14, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

An exhaust gas purification catalyst apparatus, which is superior in oxidation performance of, in particular, nitrogen monoxide, among hydrocarbons, carbon monoxide, nitrogen oxides and particulate components such as soot, included in exhaust gas from a lean burn engine, and combustion performance of light oil. The exhaust gas purification apparatus arranged with an oxidation catalyst (DOC) comprising a noble metal component for oxidizing carbon monoxide, hydrocarbons, in particular, nitrogen monoxide among nitrogen oxides, and for combusting light oil, a catalyzed soot filter (CSF) including a noble metal component for collecting a particulate component such as soot and removing by combustion (oxidation). The oxidation catalyst (DOC) has a catalyst layer where platinum (Pt), palladium (Pd) and barium oxide (BaO) are supported on alumina (Al 2 O 3 ) having a pore size of 12 to 120 nm, and ratio of platinum and palladium is 1:1 to 11:2 in weight equivalent.

First claim

The invention claimed is:

1. An exhaust gas purification apparatus, comprising:
an oxidation catalyst (DOC) comprising a noble metal component for oxidizing, in particular, nitrogen monoxide, among carbon monoxide, hydrocarbons, nitrogen oxides, and for combusting light oil,
a catalyzed soot filter (CSF) comprising a noble metal component for collecting a particulate component such as soot and removing by combustion (oxidation),
a reducing agent spraying means for supplying a reducing agent selected from a urea component or an ammonia component, and
a selective reduction catalyst (SCR) for removing by reduction of nitrogen oxides by contacting with the reducing agent,
wherein the oxidation catalyst (DOC), the catalyzed soot filter (CSF), the reducing agent spraying means, and the selective reduction catalyst (SCR) are arranged in this order from the upstream side of an exhaust gas passage, in order to purify carbon monoxide, hydrocarbons, nitrogen oxides, and particulate components such as soot, in exhaust gas discharged from a diesel engine,
the oxidation catalyst (DOC) has a catalyst layer consisting of platinum (Pt), palladium (Pd) and barium oxide (BaO) supported on alumina (Al 2 O 3 ) having a pore size of 12 to 120 nm, and ratio of platinum and palladium is 1:1 to 11:2 in weight equivalent, and
the catalyzed combustion filter (CSF) has a catalyst layer, where platinum (Pt) and palladium (Pd) are supported on alumina having a pore size of 12 to 120 nm, or a mixture of two or more kinds of alumina having different pore size within its range, and ratio of platinum and palladium is 1:1 to 11:4 in weight equivalent.

2. The exhaust gas purification apparatus according to claim 1 , wherein the catalyst layer is coated onto an integral structure-type substrate, in one or more layers.

3. The exhaust gas purification apparatus according to claim 1 , wherein the catalyst layer has a base layer composed of alumina, at the lower layer thereof.

4. The exhaust gas purification apparatus according to claim 1 , wherein the alumina having the pore size of 12 to 120 nm is a mixture of two or more kinds of alumina having different pore size.

5. The exhaust gas purification apparatus according to claim 1 , further comprising a second oxidation catalyst (DOC) installed between the catalyzed soot filter (CSF) and the reducing agent spraying means.

6. The exhaust gas purification apparatus according to claim 5 , wherein the catalyzed combustion filter (CSF) has a catalyst layer, where platinum (Pt) and palladium (Pd) are supported on alumina having a pore size of 12 to 120 nm, or a mixture of two or more kinds of alumina having different pore size within its range, and ratio of platinum and palladium is 1:1 to 11:4 in weight equivalent.

7. The exhaust gas purification apparatus according to claim 1 , wherein the barium oxide in the oxidation catalyst (DOC) is included in an amount of 0.5 to 4.0 g/L.

8. The exhaust gas purification apparatus according to claim 1 , wherein the oxidation catalyst (DOC) includes a coated amount of the catalyst layer of 50 to 300 g/L.

9. The exhaust gas purification apparatus according to claim 1 , wherein the oxidation catalyst (DOC) includes a total supported amount of the noble metals of 0.5 to 4.0 g/L in metal equivalent per volume.

10. The exhaust gas purification apparatus according to claim 1 , wherein the catalyzed soot filter (CSF) includes a coated amount of the catalyst layer of 4 to 100 g/L.

11. The exhaust gas purification apparatus according to claim 10 , wherein the catalyzed soot filter (CSF) includes a total supported amount of the noble metals of 0.05 to 2.0 g/L in metal equivalent per volume.

12. The exhaust gas purification apparatus according to claim 1 , wherein the catalyzed soot filter (CSF) includes a total supported amount of the noble metals of 0.05 to 2.0 g/L in metal equivalent per volume.

13. The exhaust gas purification apparatus according to claim 1 , further comprising an ammonia oxidation catalyst (AMOX) arranged after the selective reduction catalyst (SCR).

Assignees

• N E Chemcat Corp

Inventors

• Okajima Toshinori
• Nagata Makoto

Classifications

• B01J35/0006

  Operations & Transport · mapped topic

• F01N13/0097

  the purifying devices are arranged in a single housing · CPC title

• B01J37/0248

  Coatings comprising impregnated particles · CPC title

• B01J37/0244

  Coatings comprising several layers · CPC title

• F01N2510/06

  for exhaust purification, e.g. catalytic reaction · CPC title