Exhaust treatment system and method for treatment of an exhaust stream

Patent metadata

Field	Value
Publication number	US-10273851-B2
Application number	US-201515120089-A
Country	US
Kind code	B2
Filing date	Feb 27, 2015
Priority date	Feb 28, 2014
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

An exhaust treatment system comprising: a first oxidation catalyst to oxidize nitrogen- and/or hydrocarbon compounds in an 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, arranged downstream of said first dosage device, including a slip-catalyst primarily for reduction of nitrogen oxides (NOx), and secondarily for oxidation of additive; a second oxidation catalyst arranged downstream of said first reduction catalyst; a particulate filter arranged downstream of said oxidation catalyst; a second dosage device, arranged downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device, arranged downstream of said second dosage device for reduction of nitrogen oxides in said exhaust stream, with the use of at least one of said first and said 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 or hydrogen in said exhaust stream;
a first dosage device, arranged downstream of said first oxidation catalyst, and arranged to supply a first additive into said exhaust stream;
a first reduction catalyst device, arranged downstream of said first dosage device, and arranged for reduction of nitrogen oxides in said exhaust stream, using said first additive, wherein said first reduction catalyst device comprises at least one slip-catalyst (SC), which is arranged primarily for reduction of nitrogen oxides, and secondarily for oxidation of additive in said exhaust stream;
a second oxidation catalyst, which is arranged downstream of said first reduction catalyst device, and is arranged to oxidize one or several of nitrogen oxide and incompletely oxidized carbon compounds in said exhaust stream;
a particulate filter, which is arranged downstream of said second oxidation catalyst, and is arranged to catch and oxidize soot particles;
a second dosage device, arranged downstream of said particulate filter, and arranged to supply a second additive into said exhaust stream; and
a second reduction catalyst device, arranged downstream of said second dosage device, and arranged for reduction of nitrogen oxides in said exhaust stream, using at least one of said first and said second additives.

2. The 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. The exhaust treatment system according to claim 1 , wherein said first reduction catalyst device consisting of one from among the group of:
a first selective catalytic reduction catalyst (SCR 1 ), integrated downstream with a first slip-catalyst (SC 1 ), which is arranged primarily for reduction of nitrogen oxides, and secondarily for oxidation of a residue of additive in said exhaust stream;
a first selective catalytic reduction catalyst (SCR 1 ), followed downstream by a separate first slip-catalyst (SC 1 ), which is arranged primarily for reduction of nitrogen oxides, and secondarily for oxidation of a residue of additive in said exhaust stream;
a first slip-catalyst (SC 1 ), which is arranged primarily for reduction of nitrogen oxides, 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 ), wherein said first slip-catalyst (SC 1 ) is arranged primarily for reduction of nitrogen oxides, 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, 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 ), are arranged primarily for reduction of nitrogen oxides, 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 ), are arranged primarily for reduction of nitrogen oxides, 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 ), are arranged primarily for reduction of nitrogen oxides, and secondarily for oxidation of 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 ), are arranged primarily for reduction of nitrogen oxides, and secondarily for oxidation of additive in the exhaust stream.

4. The exhaust treatment system according to claim 1 , wherein said second reduction catalyst device consisting of 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 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 in said exhaust stream.

5. The 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.

6. The exhaust treatment system according to claim 5 , wherein said system for supply of additive comprises a dosage control device, arranged to control said at least one pump.

7. The exhaust treatment system according to claim 5 , 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, using 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, using said second dosage device.

8. The exhaust treatment system according to claim 1 , wherein said first reduction catalyst device is arranged for the reduction of said nitrogen oxides within a reduction temperature interval, which at least partly differs from an oxidation temperature interval, within which an oxidation of incompletely oxidized carbon compounds may occur in said particulate filter.

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

10. The exhaust treatment system according to claim 1 , wherein said particulate filter at least partly comprises a catalytically oxidizing coating.

11. A method for treatment of an exhaust stream, which results from a combustion in a combustion engine, said method comprising:
oxidizing compounds comprising one or several of nitrogen, carbon and hydrogen in said exhaust stream, with the use of a first oxidation catalyst;
controlling a supply of a first additive into said exhaust stream using

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