Siemens Aktiengesellschaft

Saint-gobain Centre De Recherches Et D'etudes Europeen

Infineon Technologies Ag

Ronald Neufert

Wieland Mathes

Lothar Hofmann

Klaus Wenzlawski

Frank Witzel

Dietmar Weisensel

Stefan Fischer

Malte Moeller

Günther Pajonk

Manfred Weigl

Peter Heinz Fischer

Erich Hums

Helmut Schmelz

G&uuml;nther Pajonk

Gerhard Wissler

Walter Fischer

Rainer Tost

Winfried D&ouml;lling

Reinhard Latsch

Klaus Huttenhofer

Fabiano Rodrigues

Paul Leplay

Michael Faber

J&uuml;rgen Z&uuml;rbig

Gunther Spitznagel

Adrien Vincent

Sébastien Pinson

Jurgen Zurbig

Rainer Stoephasius

Dagmar Schobert-Schaefer

A monolithic membrane-type filtration structure for filtering liquids, includes a support formed of a porous inorganic material of permeability K, the support having a tubular overall shape with a main axis, an upstream base, a downstream base, a peripheral wall delimiting an internal part and a plurality of passages parallel to the main axis of the support, formed in the internal part of the support, a membrane of permeability Kand of mean thickness tcovering the internal surface of the passages; the external hydraulic diameter of the structure satisfying the relationship &#xd8;=&#x3b1;&#xd7;[A+B&#xd7;log(K&#xd7;t/K)]; in which &#x3b1; is a coefficient between 0.85 and 1.15, and A=&#x2212;21570&#xd7;ent&#x2212;18.6&#xd7;D+19.0&#xd7;e&#x2212;2.5&#xd7;e+0.1244 B=&#x2212;11760&#xd7;D&#xd7;e+9.7&#xd7;e+3.1&#xd7;e+0.04517. Dis the mean hydraulic diameter of the passages, eis the minimum thickness of the internal walls between the passages, eis the minimum thickness of the peripheral wall of the filter.

Monolithic membrane filtration structure

A tangential filter for filtration of a fluid includes a support element, wherein, along a transverse plane perpendicular to the central axis of the support element a) the support element includes in its central portion only inner channels that do not share a common wall with its outer surface, the inner channels having a substantially equivalent hydraulic diameter, b) the support element includes peripheral channels, including at least first and second adjacent peripheral channels, each of the two channels sharing a common wall with the outer surface, c) the ratio of the hydraulic diameter of the first channel to the hydraulic diameter of the second channel is greater than or equal to 1.1, d) the number of peripheral first channels is greater than or equal to the number of peripheral second channels, e) the second channel has a hydraulic diameter substantially identical to the hydraulic diameter of the inner channels.

Tangential filter with a supporting element including a set of channels

To reduce the number of particles in an exhaust gas (A), in particular in the exhaust gas (A) from an internal-combustion engine, sulfur dioxide SOwhich is contained in the exhaust gas (A) is at least partially catalytically oxidized, in the presence of ammonia NHin a catalytic converter system having a catalytic activity which increases in the direction of flow, to form sulfur trioxide SO. The simultaneous presence of sulfur trioxide SOand ammonia NHin the exhaust-gas stream which is brought about in this way results in an agglomeration of the small and very small particles and reduction in the number thereof.

Method and device for reducing the number of particles in an exhaust gas

The invention relates to a catalytic converter and a method for cleaning the exhaust gas from an internal combustion engine which is operated with excess air. The catalytic converter has an active material made from the oxides TiO , V O , CaO and SiO , as well as WO and/or MoO . An active material of this type has the property of using the SCR method to reduce to equal extents the levels of nitrogen oxides and hydrocarbons. The CO oxidation activity of a material of this type can be increased by metering in elements selected from the group consisting of Pt, Pd, Rh, Ru and Ir in any desired inorganic form.

Catalytic converter and method for cleaning exhaust gas

A process for regenerating a catalyst, in particular a plate-type or honeycomb catalyst, which has been at least partially deactivated by catalyst poisons, is described. The catalyst is treated with a gaseous reducing agent and with a polyfunctional complex-forming agent, so that the catalyst poisons are removed.

Process for regenerating a deactivated catalyst

A process for producing a catalyst body includes providing titanium dioxide, tungsten trioxide, vanadium pentoxide, aluminum oxide, and/or silicon oxide for the catalyst body. A kneadable and/or shapable compound is processed to form a shaped body by extrusion or by coating of a support body. The shaped body is dried and is calcined to form an active compound. The calcined shaped body is artificially aged by a final heat treatment at a temperature higher than the calcination temperature to produce a catalyst body having a high resistance to deactivation at high temperatures. The starting materials include from 65 to 95% by weight of titanium dioxide, 2 to 30% by weight of tungsten trioxide, 0 to 2% by weight of vanadium pentoxide, preferably, less than 1.5%, 0.1 to 10% by weight of aluminum oxide, and 0.1 to 10% by weight of silicon dioxide. The final heat treatment is done is at 660 to 700&deg; C., drying is at 20 to 100&deg; C. prior to calcination, and calcination is at 400&deg; C. to less than 700&deg; C.

Process for producing a catalyst body

A method for cleaning diesel engine exhaust gas is described. The exhaust gas is passed over a catalytic converter with an active material which contains (% by weight) 70-95% TiO , 2-10% WO and/or MoO , 0.1-5% V O , 0.1-8% CaO, 0.1-8% Al O , 0.1-5% B O and 0.1-10% SiO . A reducing agent for a reduction of nitrogen oxides is metered into the exhaust-gas stream upstream of the catalytic converter.

Method for cleaning diesel engine exhaust gas

A process is provided for the catalytic removal of polycyclic aromatic nitro, nitroso and/or amino compounds from the exhaust gas of a combustion system, in particular a diesel engine. The exhaust gas is brought into contact with a catalytic converter which includes a catalytically active material that contains titanium dioxide, at a temperature of from 150 to 600&deg; C. The polycyclic aromatic compounds are oxidized at the catalytic converter through the use of oxygen to form nitrogen oxides, carbon dioxide and water.

Process for the catalytic removal of polycyclic aromatic nitro, nitroso and/or amino compounds

A process for catalytic removal of a pollutant from a combustion installation exhaust gas includes calculating, from operationally relevant parameters of the installation, a pollutant concentration using a predetermined characteristic diagram. A predetermined quantity of a reagent is introduced into the exhaust per unit time as a function of the calculated pollutant concentration, the reagent reacting with the pollutant at a catalytic converter. Operating states of the installation with substantially constant pollutant emission levels are determined. The pollutant concentration during an operating state of the installation with a substantially constant pollutant emission level is determined with a sensor and only a pollutant concentration from the installation in a steady operating state is used to correct the diagram. The pollutant concentration from the installation is calculated with the diagram in a non-steady operating state. An apparatus for the catalytic removal of the pollutant from the exhaust gas is also provided.

Process and apparatus for the catalytic elimination of a pollutant from the exhaust gas from a combustion installation

An exhaust system for an internal combustion with a catalytic converter connected to the exhaust pipe for cleaning the engine exhaust gas in the presence of a reducing agent also includes a condensation water collector into which the exhaust gases are diverted prior to reaching the catalytic converter. The collector condenses moisture in the exhaust gas to produce liquid water condensate that is held in a reservoir. The water condensate is combined with a reactant capable of forming a reducing agent and the aqueous solution of the reactant is introduced into the exhaust gas upstream of the catalytic converter.

System and method for reducing pollutants in the exhaust gas of an internal combustion engine

A device for simultaneously filling a container serving as a fuel tank and a container serving as a reducing-agent container with a single pump nozzle is used for environmentally friendly internal combustion engines with exhaust-gas purification systems requiring both tanks which are to be refilled repeatedly. Filler necks of the containers as well as outlet pipes disposed in the pump nozzle and assigned to the filler necks, are combined. A method for filling the containers is also provided.

Method and device for filling containers

A NO.sub.x reduction system includes an SCR catalytic converter and a metering assembly for reducing agent. A control unit for the reduction system is integrated together with the actuators and sensors as a functional unit at the reducing agent container. This provides savings in terms of lines and plug-in connections, and relieves the burden on the control unit of the internal combustion engine.

NO.sub.x reduction system with a device for metering reducing agents

An SCR catalyst containing titanium, molybdenum and vanadium has the particular characteristic that its catalytic activity is significantly less than that of a tungsten-containing catalyst. That disadvantage has been compensated for in the past by using a comparatively large volume of catalyst. In contrast to the conventional practice of using a molybdenum oxide proportion of about 10 to 12% by weight, the invention proposes that the molybdenum proportion of the catalyst, in the form of molybdenum trioxide MoO.sub.3, is about 0.01 to 5% by weight, preferably 1.5 to 4% by weight, relative to the weight of the catalyst mass. A catalyst containing this amount of molybdenum thus has an activity comparable to that of a tungsten-containing catalyst. The invention is applicable to all deNO.sub.x catalytic converters which call for the simultaneous presence of a reducing agent, in particular plate-type and honeycomb-type catalytic converters.

Catalyst for reducing the nitrogen oxide concentration in a flowing

Nitrogen oxides emitted by an internal-combustion engine operated with excess air are normally converted by the method of selective catalytic reduction by bringing the nitrogen oxides, together with ammonia, into contact with a selective catalyst. Due to the dangers associated with the use of ammonia, in a motor vehicle ammonia should only be carried in the form of a substance which liberates ammonia, generally an aqueous urea solution. A method and a device for introducing liquid into an exhaust-gas purification system according to the invention avoids frost damage to sections of the system during shutdown times and permits operation of the system at temperatures below the freezing point of the reducing agent solution being used. The method and device include a (thermally insulated) reservoir for the reducing agent liquid and a liquid supply line which is connected thereto and terminates in an outlet opening for the liquid. The reservoir and the liquid supply line can be heated. Furthermore, a heater is provided for liquefying a starting volume which is small as compared with the volume of the reservoir. The liquid supply line may also have a back-flush valve to which a gas that is under pressure can be applied. The supply line can consequently be blown free.

Method and device for introducing liquid into an exhaust-gas

A method is provided in which the reducing agent, during the starting phase of the internal-combustion engine and during operation with decreasing and, if appropriate, virtually constant exhaust gas temperature, is fed superstoichiometrically in relation to the nitrogen oxide concentration, while taking into account the temperature-dependent storage capacity of a denitration catalytic converter for the reducing agent. The reducing agent is otherwise fed substoichiometrically. In this manner, the catalytic converter is kept at all times at a preferred charge level, so that on one hand it is possible to provide sufficient stored reducing agent for the catalytic conversion and on the other hand it is possible to still have a reducing agent buffer available which avoids slip of the reducing agent. The invention can be used in all internal-combustion engines operated with air excess, such as diesel engines and lean-burn engines.

Growing community of inventors

Michelau, Germany

Ronald Neufert