IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0556336
(2004-05-06)
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등록번호 |
US-7797928
(2010-10-11)
|
우선권정보 |
EP-03010528(2003-05-10) |
국제출원번호 |
PCT/EP2004/004793
(2004-05-06)
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§371/§102 date |
20051201
(20051201)
|
국제공개번호 |
WO04/099577
(2004-11-18)
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발명자
/ 주소 |
- Friedrich, Gerhard
- Kolios, Grigorios
- Schmeisser, Volker
- Tuttlies, Ute
- Opferkuch, Frank
- Eigenberger, Gerhart
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
10 인용 특허 :
9 |
초록
▼
In a method for purifying exhaust gases in particular from lean-burn internal combustion engines having an exhaust-gas converter with a heat exchanger and catalysts arranged in inflow and/or outflow passages, the heat exchanger exhaust gas which flows in is heated by heat exchange with exhaust gas w
In a method for purifying exhaust gases in particular from lean-burn internal combustion engines having an exhaust-gas converter with a heat exchanger and catalysts arranged in inflow and/or outflow passages, the heat exchanger exhaust gas which flows in is heated by heat exchange with exhaust gas which flows. The incoming exhaust gas enters the inflow passages without encountering any obstacle susceptible to blockages, and flows through the inflow passages to a diversion region. Heat is fed to the exhaust gas by means of a burner. The burner is operated with fuel, air and engine exhaust gas in such a way that it supplies either an oxidizing or a reducing exhaust gas. Burner exhaust gas is admixed to the gas which emerges from the inflow passages and, together with this gas, enters the outflow passages, where nitrogen oxides are removed from it by a deNOxing catalyst present in the outflow passages.
대표청구항
▼
The invention claimed is: 1. A method of purifying an exhaust gases from a combustion engine in a purification unit in which the purification unit contains a fuel burner and combining counter-current heat exchange and catalytic conversion of noxious compounds, the method comprising the steps of: a)
The invention claimed is: 1. A method of purifying an exhaust gases from a combustion engine in a purification unit in which the purification unit contains a fuel burner and combining counter-current heat exchange and catalytic conversion of noxious compounds, the method comprising the steps of: a) allowing the incoming exhaust gas (2) to enter the unit via an inlet region (3) from where the incoming exhaust gas (2) is axially distributed to a plurality of parallel inflow passages (6), after flowing through the passages the incoming exhaust gas (2) is deflected in a diversion region (9), located opposite to the inlet region (3), into a plurality of parallel outflow passages (7), each of which is situated between two inflow passages (6), flowing therein an opposite direction and providing heat exchange with the incoming exhaust gas (2) and exiting the plurality of parallel outflow passages (7) through an outlet region (4) located adjacent the inlet region (3), and the inlet region (3) and the outlet region (4) are sealed with respect to one another; b) the plurality of inflow passages (6) being partially coated with an oxidation catalyst (15) for the conversion of oxidizable compounds including NO to NO2, and the plurality of parallel outflow passages (7) being partially coated with a NOx conversion catalyst (33), and all catalysts being located adjacent the diversion region (9) thereby leaving the inlet region (3), located adjacent the engine exhaust inlet, substantially catalyst-free; c) a catalytic fuel burner (19), containing at least one oxidation catalyst (33, 34), being operatable in one of a lean burn mode or a rich burn mode with air or with portion of the lean engine exhaust gas as an oxidizing agent, the burner exhaust being fed into the diversion region (9), and in the rich burn mode, the burner exhaust is further oxidized at the oxidation catalyst (34) to at least one of create additional heat and enhance NOx reduction at the NOx conversion catalyst (33). 2. The method as claimed in claim 1, further comprising the step of positioning a second oxidation catalyst (33) behind the NOx conversion catalyst (33). 3. A method for purifying exhaust gases, the gases comprising combustible and NOx containing exhaust-gas constituents, from a lean-burn internal combustion engine, in an exhaust-gas converter (1), having a heat exchanger (12) with catalysts (15, 33) arranged in at least one inflow passage (6) and at least one outflow passage (7), in which incoming exhaust gas (2) flowing in is heated by heat exchange with exhaust gas flowing out of the heat exchanger, and the heat being supplied to the incoming exhaust gas, the method comprising the steps of: allowing the incoming exhaust gas (2) to enter an inlet region (3) through a plurality of parallel inflow passages (6) of the heat exchanger (12) without encountering any diversion or flow obstacle which is susceptible to blockage, and the incoming exhaust gas (2) flowing through the plurality of parallel inflow passages into a diversion region (9), the diversion region (9) being located opposite the inlet region (3), the incoming exhaust gas (2) being deflected in the diversion region (9) into a plurality of parallel outflow passages (7), each of which is situated between two inflow passages (6), the incoming exhaust gas (2) flows in the plurality of outflow passages (7) in an opposite direction to a flow direction of the incoming exhaust gas in the plurality of inflow passages (6), whereby heat exchange between the incoming exhaust gas in the plurality of inflow passages (6) and the incoming exhaust gas in the plurality of outflow passages (7) is promoted, the incoming exhaust gas (2) exiting the plurality of outflow passages (7) via an outlet region (4) located adjacent the inlet region (3), and the inlet region (3) and the outlet region (4) being sealed with respect to one another; feeding heat in a form of burner exhaust gas to the incoming exhaust gas by a burner (19) which is arranged in the diversion region (9), the burner (19) is electrically heated and is provided with at least one oxidation catalyst (31, 32), the burner (19) being operated with fuel and one or more of air and engine exhaust gas in such a way that the burner (19) supplies either an oxidizing or a reducing (substantially CO- and H2-containing) exhaust gas, the burner (19) being operated in one of a lean burn mode and a rich burn mode with one of air and portion of the lean engine exhaust gas as an oxidizing agent, the burner exhaust gas being fed into the diversion region (9), and during operation in the rich burn mode, the burner exhaust gas being used to at least one of oxidized at the oxidation catalyst to create additional heat and enhance NOx reduction at a NOx conversion catalyst (33), admixing the burner exhaust gas with the incoming exhaust gas which emerges from the plurality of inflow passages (6) and enters the plurality of outflow passages (7) together with the burner exhaust gas, and nitrogen oxides are removed from the incoming exhaust gas by at least one deNOxing catalyst (33) which is present in the plurality of outflow passages (7), setting the gas and fuel throughput of the burner exhaust gas by a control unit (52) in such a way that, during a cold start the catalyst (15, 33) is quickly heated to an optimum operating temperature and is held at the optimum operating temperature, and a reducing burner exhaust gas is generated at regular intervals to regenerate the deNOxing catalyst (33). 4. The method as claimed in claim 3, further comprising the step of setting the required temperature and composition of the incoming exhaust gas for sulfur regeneration of an NOx storage catalyst, which forms the deNOxing catalyst (33), at periodic intervals by the control unit (52), periodically regenerating the NOx storage catalyst by one of a fuel rich engine exhaust gas or by periodically adding fuel rich burner exhaust gas to the diversion region (9), and accomplishing a sulfur regeneration by adding fuel rich burner exhaust gas over an extended period of time. 5. The method as claimed in claim 3, further comprising the step of combining one or more of all of the elements which are required for the incoming exhaust gas purification, incoming exhaust gas muffling and the discharge of heat in one exhaust-gas converter (1), the muffling being boosted by one or more of different lengths of the plurality of inflow and outflow passages (6, 7) and by other passive or active muffling elements in the inlet region (3), in one or more of the outlet region (4) and in the diversion region (9) of a hood (8), and the discharge of heat, in particular for heating a passenger compartment, being effected by one or more of the incoming exhaust gas in the diversion region (9) and the hot gas from the burner (19) being one of partially or completely passed via a heat exchanger (51) which is suitable for this purpose. 6. The method as claimed in claim 3, further comprising the step of operating at least two substantially identical exhaust-gas converters (1) in parallel for the period of regeneration one or more of the NOx conversion and NOx storage catalyst (33) or of the particulate filter (35), throttling the exhaust-gas stream through the unit to be regenerated so that the regeneration is carried out with a considerably reduced consumption of at least one of additional energy and a regeneration agent. 7. The heat supply apparatus for use in the method as claimed in claim 3, wherein which heat supply apparatus is a catalytic burner (19), the catalytic burner (19) having an at least partially electrically heatable catalyst (31, 32), which is acted on by a mixture of an oxygen-containing gas (30) and a fuel (29) or a mixture of gas (30), fuel (29) and water, the control unit (52) facilitates altering the supply of gas, fuel and water in such a way that the fuel is either completely burnt or is at least partially converted into CO and H2, and the catalytic burner (19) being connected to a hood (8) of the housing (5) in such a manner that the fuel gas is fed into the diversion region (9) or the filter admission space (37) and is uniformly distributed between the passages of the filter (35) or the plurality of outflow passages (7), the uniform distribution being ensured by one of internal fittings and a suitable flow guidance. 8. The method as claimed in claim 3, for purifying incoming exhaust gases further comprising combustible, NOx containing exhaust gas constituents in one of particulate or soot form, from diesel engines, further comprising the steps of: passing the incoming exhaust gas (6) from the the plurality of inflow passages (6) into a particulate filter (35) arranged in the diversion region (9) and passing the incoming exhaust gas (6) through the particulate filter (35) into the the plurality of outflow passages (7), setting the gas and fuel throughput of the burner exhaust gas being by the control unit (52) in such a way that the temperature of the particulate filter (35) is either permanently kept at such a high level that the soot which is deposited burns off, or the temperature is periodically raised to a level sufficient for the soot to burn off. 9. The method as claimed in claim 8, further comprising the step of setting the temperature of the particulate filter (35), which is required for continuous or periodic regeneration thereof, by reducing burner exhaust gas being burnt on an oxidation catalyst (50), which is arranged on the outflow side of the particulate filter (35) and in thermal contact with the latter. 10. An apparatus for purifying exhaust gases having one of combustible and NOx containing exhaust gas constituents, from lean-burn internal combustion engines, the apparatus comprising: a parallel passage arrangement (16) formed from a monolith of a plurality of passages consisting of ceramic or metallic material with a rectangular passage cross section, every second row of the passages being used as an inflow passage (6) and every other row of the passages being used as outflow passage (7), the outflow passages (7) being closed off at an end side facing an inlet region (3) and being laterally open toward an outlet region (4) through continuous slots; a housing (5) with a hood (8) and openings for incoming and outgoing exhaust gas surrounding the monolith, the inlet region (3) being sealed off with respect to the outlet region (4) by a sealing device (17) between the monolith and the housing (8), and the arrangement of a purification component (15, 33, 34, 35) required for the conversion, being effected by coating passage walls, the monolith, which is used for the parallel passage arrangement (16), over the entire length or at least in the filter region (40), being made from a porous filter ceramic or a porous metal suitable for the particulate filtering, one or more of the inflow and outflow passages of the monolith, starting at the inlet region (3), being at least substantially gas tight or being made gas tight by one of a glaze or corresponding coating, over a length of heat exchange and catalyst regions (41, 42), the inflow passages (6) being closed off at an end face which is directed toward the hood (8), so that in the filter region (40) the exhaust gas passes from the inflow passages (6) into the outflow passages (7) and being filtered in the process, and the particulates which have been deposited on the filter being burnt off by an electrical heater which is integrated in the filter in a region of one of the hood (8) or by the hot fuel gas fed into the hood (8) from one of a thermal or catalytic burner (19). 11. The apparatus as claimed in claim 10, wherein a gas exit side of one of the particulate filter (35) or of the filter region (40) is provided with an oxidation catalyst. 12. An apparatus for purifying exhaust gases having exhaust-gas constituents which are one or more of combustible, contain NOx and are in particulate or soot form, the exhaust gases coming from lean-burn internal combustion engines, the apparatus comprising: an exhaust-gas heat exchanger (12), which includes a housing (5) and a plurality of inflow passages (6), arranged next to one another in the housing (5), and outflow passages (7) located between the inflow passages (6), one of the inflow passages (6) or the outflow passages (7) being closed on all sides at lateral surfaces (10, 11) and, together with the housing (5), forming the outflow passages (7) or inflow passages (6) located between them, the inflow passages (6) and the outflow passages (7) together forming a parallel-passage arrangement (16), and to achieve a constant distance between adjacent inflow passages (6) or outflow passages (7), either spacer elements (14) are arranged therein, or the side walls (10) of the inflow passages (6) are supported against one another on account of being profiled, and the housing (5) forms a diversion region (9) at a transition from the inflow passages (60) into the outflow passages (7), a catalytic burner (19), which is arranged in one of the diversion region (9) or a filter admission space (37) of the exhaust-gas heat exchanger (12), components (15, 33, 34, 35) for purifying one of the conversion, separation or storage of the exhaust-gas constituents which are one or more of combustible, contain NOx and are in particulate or soot form, the purifying components are arranged within the exhaust-gas heat exchanger (12), an inlet region (3) and an outlet region (4), which are formed by the housing (5), one or more of the inflow passages (6) and the outflow passages (76), at the filter admission space (37), being connected to the respectively adjacent passages (7, 6) and the housing (5) and sealed with respect to one another by one or more of welding, soldering, folding and a sealing device (17) in such a way that no leakage flow or only a negligible leakage flow occurs between the inlet region (3) and the outlet region (4). 13. The apparatus as claimed in claim 12, wherein the inlet region (3) is arranged in such a manner that the flow to the inflow passages (6) is in an axial direction, and the outlet region (4) is arranged in such a manner that the exhaust gases exits the outflow passages (7) laterally. 14. The apparatus as claimed in claim 12, wherein the inflow passages (6) are produced by single or multiple, concertina-like folding of a profiled or flat sheet-metal strip, the folding taking place either longitudinally or transversely with respect to a main direction of flow in the inflow passages (6). 15. The apparatus as claimed in claim 12, wherein the inflow passages (6) in the inlet region (3) are connected by one or more of folding, combining side walls (10) of the inflow passages (6) and soldered or welded joints, and are covered by caps (13), in such a manner as to form an axial entry which is favorable in terms of flow. 16. The apparatus as claimed in claim 12, wherein one of the inflow passages (6) or outflow passages (7), which are closed on all sides at their lateral surface, are connected at an end face in the diversion region (9) to a particulate filter (35) or are closed at their end face in the diversion region (9) and before this have lateral openings, which one of consist of a porous material or are covered with a porous material, over the length of the filter region (40).
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