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1. WO1996004980 - METHOD FOR THE CATALYTIC REACTION OF OXIDES OF NITROGEN IN THE EXHAUST FROM AN INTERNAL-COMBUSTION ENGINE

Publication Number WO/1996/004980
Publication Date 22.02.1996
International Application No. PCT/DE1995/000646
International Filing Date 16.05.1995
Chapter 2 Demand Filed 12.12.1995
IPC
B01D 53/30 2006.01
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases or aerosols
30Controlling by gas-analysis apparatus
B01D 53/86 2006.01
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases or aerosols
34Chemical or biological purification of waste gases
74General processes for purification of waste gases; Apparatus or devices specially adapted therefor
86Catalytic processes
B01D 53/94 2006.01
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases or aerosols
34Chemical or biological purification of waste gases
92of engine exhaust gases
94by catalytic processes
F01N 3/20 2006.01
FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
3Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
08for rendering innocuous
10by thermal or catalytic conversion of noxious components of exhaust
18characterised by methods of operation; Control
20specially adapted for catalytic conversion
CPC
B01D 53/30
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols,
30Controlling by gas-analysis apparatus
B01D 53/8696
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols,
34Chemical or biological purification of waste gases
74General processes for purification of waste gases; Apparatus or devices specially adapted therefor
86Catalytic processes
8696Controlling the catalytic process
B01D 53/9431
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols,
34Chemical or biological purification of waste gases
92of engine exhaust gases
94by catalytic processes
9404Removing only nitrogen compounds
9409Nitrogen oxides
9431Processes characterised by a specific device
B01D 53/9495
BPERFORMING OPERATIONS; TRANSPORTING
01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
DSEPARATION
53Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols,
34Chemical or biological purification of waste gases
92of engine exhaust gases
94by catalytic processes
9495Controlling the catalytic process
F01N 2560/06
FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
2560Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
06the means being a temperature sensor
F01N 2570/18
FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
2570Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
18Ammonia
Applicants
  • SIEMENS AKTIENGESELLSCHAFT [DE/DE]; Wittelsbacherplatz 2 D-80333 München, DE (AllExceptUS)
  • NEUFERT, Ronald [DE/DE]; DE (UsOnly)
  • MATHES, Wieland [DE/DE]; DE (UsOnly)
  • SCHOBERT-SCHÄFER, Dagmar [DE/DE]; DE (UsOnly)
  • HOFMANN, Lothar [DE/DE]; DE (UsOnly)
Inventors
  • NEUFERT, Ronald; DE
  • MATHES, Wieland; DE
  • SCHOBERT-SCHÄFER, Dagmar; DE
  • HOFMANN, Lothar; DE
Priority Data
P 44 28 329.610.08.1994DE
Publication Language German (DE)
Filing Language German (DE)
Designated States
Title
(DE) VERFAHREN ZUR KATALYTISCHEN UMSETZUNG VON IM ABGAS EINES VERBRENNUNGSMOTORS ENTHALTENEN STICKOXIDEN
(EN) METHOD FOR THE CATALYTIC REACTION OF OXIDES OF NITROGEN IN THE EXHAUST FROM AN INTERNAL-COMBUSTION ENGINE
(FR) PROCEDE DE CONVERSION CATALYTIQUE D'OXYDES D'AZOTE CONTENUS DANS LES GAZ D'ECHAPPEMENT D'UN MOTEUR A COMBUSTION INTERNE
Abstract
(DE)
Bei der katalytischen Umsetzung von im Abgas eines mit Luftüberschuß betriebenen Verbrennungsmotors enthaltenen Stickoxiden muß ein für die katalytische Reaktion erforderliches Reduktionsmittel zugeführt werden. Hierbei muß die Reduktionsmittelzudosierung den schnell wechselnden Betriebszuständen eines Verbrennungsmotors gerecht werden können. Diesbezüglich existiert derzeit keine zufriedenstellende Lösung. Hierzu ist erfindungsgemäß ein Verfahren vorgesehen, bei dem das Reduktionsmittel während der Startphase des Verbrennungsmotors und beim Betrieb mit sinkender und gegebenenfalls nahezu konstanter Abgastemperatur unter Berücksichtigung der temperaturabhängigen Speicherkapazität eines Denitrierungs-Katalysators für das Reduktionsmittel überstöchiometrisch im Bezug zur Stickoxidkonzentration zudosiert wird, wobei das Reduktionsmittel ansonsten unterstöchiometrisch zudosiert wird. Auf diese Weise wird der Katalysator jederzeit auf einem bevorzugten Füllstand gehalten, um einerseits ausreichend gespeichertes Reduktionsmittel zur katalytischen Umsetzung bereitstellen zu können und andererseits noch über einen Reduktionsmittelpuffer zu verfügen, wodurch ein Schlupf des Reduktionsmittels vermieden wird. Die Erfindung ist bei allen mit Luftüberschuß betriebenen Verbrennungsmotoren, wie z.B. Dieselmotoren und Magermotoren, einsetzbar.
(EN)
In the catalytic reaction of nitrogen oxides contained in the exhaust gases from an internal-combustion engine operated with an excess of air, a reducing agent must be supplied for the catalytic reaction to take place. This metered addition of reducing agent must be adaptable to the rapidly changing operating conditions in the engine. Up to now, there has been no satisfactory solution to this problem. The invention proposes a method in which the reducing agent is added, in quantities which are greater than stoichiometric with respect to the nitrogen oxide concentration, during the engine-starting phase and during operation at a falling and optionally at essentially constant exhaust-gas temperatures, taking into consideration the temperature-dependent capacity of the denitrogenation catalyst to store reducing agent, the reducing agent being otherwise added in less than stoichiometric quantities. In this way, the catalyst is kept at the preferred level at all times in order to ensure that sufficient stored reducing agent is available for the catalytic reaction and also to provide a reducing-agent buffer, thus avoiding a shortage of reducing agent. The invention is applicable to all internal-combustion engines operated with an excess of air, such as diesel engines and lean-mixtures engines.
(FR)
Pendant la conversion catalytique d'oxydes d'azote contenus dans les gaz d'échappement d'un moteur à combustion interne actionné avec un excès d'air, un agent de réduction nécessaire à la réaction catalytique doit être acheminé. L'apport dosé d'agent de réduction doit pouvoir être ajusté aux états de fonctionnement rapidement changeants d'un moteur à combustion interne. Jusqu'à présent, on ne disposait pas de solution satisfaisante. Il est prévu un procédé selon lequel pendant la phase de démarrage du moteur à combustion interne et pendant le fonctionnement à température décroissante et éventuellement approximativement constante des gaz d'échappement, en tenant compte de la capacité, variable avec la température, d'un catalyseur de dénitration à stocker l'agent de réduction, l'agent de réduction est ajouté de manière dosée dans des quantités surst÷chiométriques par rapport à la concentration en oxyde d'azote, l'agent de réduction étant sans cela ajouté de manière dosée dans des quantités sous-st÷chiométriques. Le catalyseur reste ainsi maintenu à tout moment à un niveau de remplissage préféré, afin d'une part de garantir un volume suffisant d'agent de réduction en vue de la conversion catalytique et d'autre part de disposer d'un tampon d'agent de réduction pour éviter une perte d'énergie dudit agent de réduction. Cette invention s'utilise dans tous les moteurs à combustion interne actionnés par excès d'air, tels que les moteurs Diesel et les moteurs à mélange pauvre.
Also published as
US08798517
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