System and method for purification of an exhaust stream by use of two reduction catalysts

Patent metadata

Field	Value
Publication number	US-10267197-B2
Application number	US-201515120075-A
Country	US
Kind code	B2
Filing date	Feb 27, 2015
Priority date	Feb 28, 2014
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

An exhaust treatment system comprising a first oxidation catalyst to oxidize nitrogen and/or carbon compounds in an exhaust stream and a first dosage device downstream of said first oxidation catalyst to supply a first additive. A first reduction catalyst device is arranged downstream of said first dosage device for reduction of nitrogen oxides using said first additive, and for the generation of heat, through at least one exothermal reaction with said exhaust stream. A particulate filter arranged downstream of said first reduction catalyst device to catch soot particles and a second dosage device, arranged downstream of said particulate filter to supply a second additive. A second reduction catalyst device is arranged downstream of said second dosage device for reduction of nitrogen oxides in said exhaust stream, through 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, wherein said system comprises:
an 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 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, through the use of said first additive, and for generation of heat with at least one exothermal reaction with said exhaust stream, whereby said generated heat from the at least one exothermal reaction enables regeneration of one or more sulphur contaminated components in said exhaust treatment system;
a particulate filter, arranged downstream of said first reduction catalyst device, and configured to catch and oxidize soot particles;
a second dosage device, arranged downstream of said particulate filter, and configured to supply a second additive into said exhaust stream; and
a second reduction catalyst device, arranged downstream of said second dosage device, and configured for reduction of nitrogen oxides in said exhaust stream, through the use of 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 AR-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 ), which is arranged to generate said heat;
a first selective catalytic reduction catalyst (SCR 1 ), integrated downstream with a first slip-catalyst (SC 1 ), wherein said first selective catalytic reduction catalyst (SCR 1 ), and/or said first slip-catalyst (SC 1 ), are arranged to generate said heat, and wherein said first slip-catalyst (SC 1 ) is arranged to oxidize a residue of additive, and/or to assist said first selective catalytic reduction catalyst (SCR 1 ) with an additional reduction of nitrogen oxides 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 selective catalytic reduction catalyst (SCR 1 ), and/or said first slip-catalyst (SC 1 ), are arranged to generate said heat, and wherein said first slip-catalyst (SC 1 ) is arranged to oxidize a residue of additive, and/or to assist said first selective catalytic reduction catalyst (SCR 1 ) with an additional reduction of nitrogen oxides NO x in said exhaust stream;
a first slip-catalyst (SC 1 ), which is arranged to generate said heat, and which is arranged primarily to reduce nitrogen oxides, and secondarily for oxidation of a residue 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 to oxidize additive, and/or to assist said first selective catalytic reduction catalyst (SCR 1 ) with a reduction of nitrogen oxides NO x in the exhaust stream, and wherein said first selective catalytic reduction catalyst (SCR 1 ), and/or said first slip-catalyst (SC 1 ), are arranged to generate said heat;
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 to oxidize additive, and/or to assist said first selective catalytic reduction catalyst (SCR 1 ) with a reduction of nitrogen oxides in the exhaust stream, and wherein said first selective catalytic reduction catalyst (SCR 1 ), and/or said first slip-catalyst (SC 1 ), are arranged to generate said heat; 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 to oxidize additive, and/or to assist said first selective catalytic reduction catalyst (SCR 1 ) with a reduction of nitrogen oxides in the exhaust stream, and wherein said first selective catalytic reduction catalyst (SCR 1 ), said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst SC 1b , are arranged to generate said heat;
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 to oxidize additive, and/or to assist said first selective catalytic reduction catalyst (SCR 1 ) with a reduction of nitrogen oxides in the exhaust stream, and wherein said first selective catalytic reduction catalyst (SCR 1 ), said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst (SC 1b ), are arranged to generate said heat;
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 said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst (SC 1b ), are arranged primarily for reduction of nitrogen oxides NOR, and secondarily for oxidation of additive in the exhaust stream, and wherein said first selective catalytic reduction catalyst (SCR 1 ), said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst (SC 1b ), are arranged to generate said heat;
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 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 the exhaust stream, and wherein said first selective catalytic reduction catalyst (SCR 1 ), said first slip-catalyst (SC 1 ), and/or said additional first slip-catalyst (SC 1b ), are arranged to generate said heat; a first selective catalytic reduction catalyst (SCR 1 ), combined with a purely oxidising coating in its outlet part, wherein said first selective catalytic reduction catalyst (SCR 1 ), combined with a purely oxidising coating in its outlet part, is arranged to generate said heat;
a first slip-catalyst (SC 1 ), integrated downstream with a first selective catalytic reduction catalyst (SCR 1 ), combined with a purely oxidising coating in its outlet part, wherein said first slip-catalyst (SC 1 ) is arranged primarily to reduce nitrogen oxides, and secondarily for oxidation of additive in said exhaust stream, and wherein said first slip-catalyst (SC 1 ), and/or said first selective catalytic reduction catalyst (SCR 1 ), combined with a purely oxidising coating in its outlet part, are arranged to generate said heat; and
a first slip-catalyst (SC 1 ), followed downstream by a separate first selective catalytic reduction catalyst (SCR 1 ), combined with a purely oxidising coating in its outlet part, wherein said first slip-catalyst (SC 1 ) is arranged primarily to reduce nitrogen oxides, and secondarily for oxidation of additive in said exhaust stream, and wherein said first slip-catalyst (SC 1 ), and/or said first selective catalytic reduction catalyst (SCR 1 ), combined with a purely oxidising coating in its outlet part, is arranged to

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