Device and method comprising double reducing devices and a catalytically coated particle filter for treatment of an exhaust stream

Patent metadata

Field	Value
Publication number	US-10364724-B2
Application number	US-201515314451-A
Country	US
Kind code	B2
Filing date	Feb 27, 2015
Priority date	Feb 28, 2014
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

An exhaust treatment system comprising: a first oxidation catalyst to oxidize nitrogen compounds and/or hydrocarbon compounds in said exhaust stream; a first dosage device downstream of said first oxidation catalyst to supply a first additive into said exhaust stream; a first reduction catalyst device downstream of said first dosage device for reduction of nitrogen oxides in said exhaust stream using said first additive; a particulate filter, comprising a catalytically oxidizing coating downstream of said first reduction catalyst device to catch soot particles and oxidize one or several of nitrogen oxide and incompletely oxidized carbon compounds in said exhaust stream; a second dosage device downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device downstream of said second dosage device for a reduction of nitrogen oxides in said exhaust stream, using at least one of said first and second additive.

First claim

The invention claimed is:

1. An exhaust treatment system, arranged for treatment of an exhaust stream, which results from a combustion in a combustion engine, said system comprising:
a first oxidation catalyst, arranged to oxidize compounds comprising one or several of nitrogen, carbon and hydrogen in said exhaust stream;
a first dosage device, arranged downstream of said oxidation catalyst, and arranged to supply a first additive in said exhaust stream;
a first reduction catalyst device, arranged downstream of said first dosage device, and arranged for reduction of nitrogen oxides NO x in said exhaust stream with the use of said first additive, wherein said first reduction catalyst device comprises a first slip-catalyst (SC 1 ), which is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
a particulate filter, at least partly comprising a catalytically oxidizing coating, which is arranged downstream of said first reduction catalyst device, and is arranged to catch and to oxidize soot particles, and to oxidize one or several of nitrogen oxide NO and incompletely oxidized carbon compounds in said exhaust stream;
a second dosage device, arranged downstream of said particulate filter, and arranged to supply a second additive in said exhaust stream; and
a second reduction catalyst device, arranged downstream of said second dosage device, and arranged for reduction of nitrogen oxides NO x in said exhaust stream, through the use of at least one of said first and said second additives.

2. An exhaust treatment system according to claim 1 , wherein at least one of said first and second additives comprises ammonia, or a substance from which ammonia may be extracted and/or released.

3. An exhaust treatment system according to claim 1 , wherein said first reduction catalyst device comprises one from among the group of:
a first selective catalytic reduction catalyst (SCR 1 ), integrated downstream with a first slip-catalyst (SC 1 ), wherein said first slip-catalyst (SC 1 ) is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
a first selective catalytic reduction catalyst (SCR 1 ), followed downstream by a separate first slip-catalyst (SC 1 ), wherein said first slip-catalyst (SC 1 ) is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
said first slip-catalyst (SC 1 ), arranged primarily to reduce nitrogen oxides NO x , and secondarily to oxidize additive in said exhaust stream;
a first slip-catalyst (SC 1 ), integrated downstream with a first selective catalytic reduction catalyst (SCR 1 ), wherein said first slip-catalyst (SC 1 ) is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
a first slip-catalyst (SC 1 ), followed downstream by a separate first selective catalytic reduction catalyst (SCR 1 ), wherein said first slip-catalyst (SC 1 ) is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
a first slip-catalyst (SC 1 ), integrated downstream with a first selective catalytic reduction catalyst (SCR 1 ), integrated downstream with an additional first slip-catalyst (SC 1b ), wherein said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst (SC 1b ), is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
a first slip-catalyst (SC 1 ), followed downstream by a separate first selective catalytic reduction catalyst (SCR 1 ), followed downstream by a separate additional first slip-catalyst (SC 1b ), wherein said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst (SC 1b ), is arranged primarily for reduction of nitrogen oxides NO x , and secondarily for oxidation of additive in said exhaust stream;
a first slip-catalyst (SC 1 ), integrated downstream with a first selective catalytic reduction catalyst (SCR 1 ), followed downstream by a separate additional first slip-catalyst (SC 1b ), wherein the first slip-catalyst (SC 1 ), and/or the additional first slip-catalyst (SC 1b ), is arranged primarily to reduce nitrogen oxides NO x , and secondarily to oxidize additive in the exhaust stream; and
a first slip-catalyst (SC 1 ), followed downstream by a separate first selective catalytic reduction catalyst (SCR 1 ), integrated downstream with a separate additional first slip-catalyst (SC 1b ), wherein the first slip-catalyst (SC 1 ), and/or the additional first slip-catalyst (SC 1b ), is arranged, primarily to reduce nitrogen oxides (NO x ), and secondarily to oxidize additive in the exhaust stream.

4. An exhaust treatment system according to claim 1 , wherein said second reduction catalyst device comprises one from among the group of:
a second selective catalytic reduction catalyst (SCR 2 );
a second selective catalytic reduction catalyst (SCR 2 ), integrated downstream with a second slip-catalyst (SC 2 ), wherein said second slip-catalyst (SC 2 ) is arranged to oxidize a residue of additive, and/or to assist said second selective catalytic reduction catalyst (SCR 2 ) with an additional reduction of nitrogen oxides NO x in said exhaust stream; and
a second selective catalytic reduction catalyst (SCR 2 ), followed downstream by a separate second slip-catalyst (SC 2 ), wherein said second slip-catalyst (SC 2 ) is arranged to oxidize a residue of additive, and/or to assist said second selective catalytic reduction catalyst (SCR 2 ) with an additional reduction of nitrogen oxides NO x in said exhaust stream.

5. An exhaust treatment system according to claim 1 , wherein said particulate filter is the first exhaust treatment system component, which said exhaust stream reaches after having passed said first reduction catalyst device.

6. An exhaust treatment system according to claim 1 , wherein said exhaust treatment system comprises a system for supply of additive, which comprises at least one pump, arranged to supply said first and second dosage device with said first and second additive, respectively.

7. An exhaust treatment system according to claim 6 , wherein said system for supply of additive comprises a dosage control device, arranged to control said at least one pump.

8. An exhaust treatment system according to claim 6 , wherein said system for supply of additive comprises a dosage control device, comprising:
a first pump control device, arranged to control said at least one pump, wherein a first dosage of said first additive is supplied to said exhaust stream through the use of said first dosage device; and
a second pump control device, arranged to control said at least one pump, wherein a second dosage of said second additive is supplied to said exhaust stream through the use of said second dosage device.

9. An exhaust treatment system according to claim 1 , wherein said first reduction catalyst device is arranged for the reduction of said nitrogen oxides NO x within a reduction temperature interval T red , which at least partly differs from an oxidation temperature interval T ox , within which an oxidation of incompletely oxidized carbon compounds may occur in said particulate filter; T red ≠T ox .

10. An exhaust treatment system according to claim 1 , wherein said first oxidation catalyst is arranged to generate heat for components fitted downstream.

11. A method for treatment of an exhaust stream, which results from a combustion in a combustion engine, said method comprising:
oxidizing of compounds comprising one or sever

Assignees

• Scania Cv Ab

Inventors

• Nilsson Magnus
• Birgersson Henrik

Classifications

• B01D53/9477

  with catalysts positioned on separate bricks, e.g. exhaust systems · CPC title

• B01D2251/2062

  Ammonia · CPC title

• B01D2255/1021

  Platinum · CPC title

• B01D2255/904

  Multiple catalysts · CPC title

• B01D2251/2067

  Urea · CPC title