Selective catalytic reduction system for exhaust gas treatment, and exhaust gas purification apparatus for lean combustion engines comprising selective catalytic reduction system for exhaust gas treatment

Patent metadata

Field	Value
Publication number	US-2026021449-A1
Application number	US-202319099964-A
Country	US
Kind code	A1
Filing date	Jul 11, 2023
Priority date	Aug 4, 2022
Publication date	Jan 22, 2026
Grant date	—

Abstract

A selective catalytic reduction system for exhaust gas treatment may allow improved NO x and N 2 O removal performance, an exhaust gas purification apparatus for lean combustion engines comprising the selective catalytic reduction system for exhaust gas treatment, and the like. A selective catalytic reduction system for exhaust gas treatment may include one or more catalyst carriers, and a plurality of catalyst regions provided on the catalyst carrier, the catalyst regions include at least a first catalyst region containing iron-supported zeolite, a second catalyst region A2 containing iron-supported zeolite, and a third catalyst region containing copper-supported zeolite, in this order from the upstream side of an exhaust gas flow channel. The iron-supported zeolite contains zeolite may include BEA, CHA, FAU, MOR, MFI, and/or FER skeletal structure(s), and the copper-supported zeolite contains zeolite include CHA, AEI, AFX, and/or AFT skeletal structure(s).

First claim

1 . A selective catalytic reduction system configured for exhaust gas treatment that is arranged in an exhaust gas flow channel and purifies an exhaust gas passing through the exhaust gas flow channel, the selective catalytic reduction system comprising:
a catalyst carrier; and a plurality of catalyst regions provided on the catalyst carrier, wherein the plurality of catalyst region comprises (i) a first catalyst region comprising an iron-supported zeolite and arranged on the upstream side of the exhaust gas flow channel, (ii) a second catalyst region comprising an iron-supported zeolite and arranged on the downstream side of the exhaust gas flow channel with respect to the first catalyst region, and (iii) a third catalyst region comprising a copper-supported zeolite and arranged on the downstream side of the exhaust gas flow channel with respect to the second catalyst region, wherein the iron-supported zeolite comprises zeolite comprising a BEA, CHA, FAU, MOR, MFI, and/or FER skeletal structure, and iron supported on the zeolite, and wherein the copper-supported zeolite comprises zeolite comprising a CHA, AEI, AFX, and/or AFT skeletal structure, and copper supported on the zeolite.

2 . The system of claim 1 , wherein the first catalyst region comprises iron-supported BEA zeolite,
wherein the second catalyst region comprises iron-supported CHA zeolite, and wherein the third catalyst region comprises copper-supported CHA zeolite.

3 . The system of claim 1 , wherein the first catalyst region supported is present in 10 g/L or more in terms of zeolite per L of the catalyst carrier,
wherein the second catalyst region supported is present in 10 g/L or more in terms of zeolite per L of the catalyst carrier, and wherein the third catalyst region supported is present in 10 g/L or more in terms of zeolite per L of the catalyst carrier.

4 . The system of claim 1 , wherein, when a total length of the first catalyst region, the second catalyst region, and the third catalyst region supported is defined as 100, ratios of lengths of the catalyst regions supported satisfy:
the first catalyst region supported has a first length of in a range of from 5 to 40, the second catalyst region supported has a second length of in a range of from 5 to 40, and the third catalyst region supported has a third length of in a range of from 50 to 90.

5 . The system of claim 1 , wherein the catalyst carrier comprises a first catalyst carrier, and
wherein the first catalyst region, the second catalyst region, and the third catalyst region are provided on the first catalyst carrier.

6 . The system of claim 1 , wherein the catalyst carrier comprises a first catalyst carrier and a second catalyst carrier,
wherein the first catalyst region and the second catalyst region are provided on the first catalyst carrier, and wherein the third catalyst region is provided on the second catalyst carrier.

7 . The system of claim 1 , wherein the catalyst carrier comprises a first catalyst carrier and a second catalyst carrier,
wherein the first catalyst region is provided on the first catalyst carrier, and wherein the second catalyst region and the third catalyst region are provided on the second catalyst carrier.

8 . The system of claim 1 , wherein the catalyst carrier comprises a first catalyst carrier, a second catalyst carrier, and a third catalyst carrier,
wherein the first catalyst region is provided on the first catalyst carrier, wherein the second catalyst region is provided on the second catalyst carrier, and wherein the third catalyst region is provided on the third catalyst carrier.

9 . The system of claim 1 , wherein the catalyst carrier comprises a flow-through honeycomb structure.

10 . The system of claim 1 , wherein the exhaust gas flow channel is an exhaust gas flow channel of a diesel engine.

11 . An exhaust gas purification apparatus configured for a lean combustion engine, comprising:
an oxidation catalyst, arranged in an exhaust gas flow channel, suitable to oxidize CO, HC, NO, and/or NH 3 in an exhaust gas discharged from the lean combustion engine; a catalyst-coated particulate filter, arranged in the exhaust gas flow channel, configured to collect particulate components in the exhaust gas, and combust or oxidize and remove the particulate components; a reducing agent supplying unit, configured to supply a reducing agent comprising a urea component and/or an ammonia component into the exhaust gas flow channel; and the selective catalytic reduction system of claim 1 . arranged in the exhaust gas flow channel. configured to absorb ammonia and bring the ammonia into contact with NO x to perform reduction.

Assignees

• N E Chemcat Corp

Inventors

• Kumamoto Kazunori
• Hihara Takashi

Classifications

• F01N2610/02

  the substance being ammonia or urea · CPC title

• F01N2370/04

  Zeolitic material · CPC title

• F01N3/2803

  characterised by structure, by material or by manufacturing of catalyst support · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• F01N3/106

  Auxiliary oxidation catalysts · CPC title