Siemens Aktiengesellschaft

Siemens Aktiengesell Schaft

Wieland Mathes

Lothar Hofmann

Ronald Neufert

Klaus Wenzlawski

Udo Klumpp

Dietmar Weisensel

Frank Witzel

Rainer Tost

Kurt Schardt

Raimund M&uuml;ller

Manfred Weigl

Erwin Achleitner

Helmut Schmelz

Ralf Sigling

Gerhard Wissler

Wolfgang Bauer

Reinhard Latsch

Winfried D&ouml;lling

Klaus Rusch

Detlev Schoppe

Oliver Pfaff

J&uuml;rgen Z&uuml;rbig

Jochen Jacobitz

Petra Anette Rusch

Steffen Schnapp

Winfried Doelling

Raimund Müller

Hellmuth Kiesewetter

Elisabeth Hügging

Jurgen Zurbig

Rainer Stoephasius

Dagmar Schobert-Schaefer

A material composite that is vacuum-tight and resistant to thermal shocks is disclosed along with a method for the production thereof and to its use. A permanent connection between an aluminum oxide sapphire and an aluminum oxide ceramic is attained by a first connecting later comprised of a manganese-silicate glass, in which at least one of the metals molybdenum, tungsten, palladium or platinum is incorporated, and by a second connecting layer comprised of a manganese-silicate glass. To this end, the individual materials are fused by sintering. The material composite is used, for example, for inserting a window comprised of aluminum oxide sapphire into a housing for a light-ignitable thyristor.

Material composite and production and use of the material composite

The process and the device are provided for the selective catalytic reduction of nitrogen oxides in an oxygen-containing gaseous medium. The reducing agent required for the reaction is prepared in a separate preparation reactor. A substance that can be converted into the reducing agent is introduced into a carrier gas in the preparation reactor and, as a result, is converted by substantially thermal conversion. The energy required for the conversion is provided by the carrier gas.

Process and device for the selective catalytic reduction of nitrogen oxides in an oxygen-containing gaseous medium

The method and the device are configured for the catalytic removal of a pollutant contained in an exhaust gas of a combustion system using a reagent. A temporal mean, or time average, is formed for the concentration of the pollutant in the exhaust gas. The catalytic converter is laid out for complete conversion if the reagent is introduced stoichiometrically. Here, the reagent is introduced in substoichiometric proportions with respect to the time average of the pollutant content.

Method and device for the catalytic removal of a pollutant contained in an exhaust gas of a combustion system

Exhaust gas to be cleaned is introduced into a conversion and mixing duct and the exhaust gas flows through the duct along a predetermined longitudinal direction. A reducing agent, such as aqueous urea solution, is injected into the exhaust gas stream in the conversion and mixing duct. The exhaust gas stream is then deflected into a reaction duct which extends parallel to or coaxially around the conversion and mixing duct. The exhaust gas then flows in the opposite direction through the reaction duct. A reduction catalyst is disposed in the reaction duct, where the reducible components of the exhaust gas are reduced. The exhaust gas cleaned in this manner is then discharged from the reaction duct.

Process for the catalytic cleaning of the exhaust gas from a combustion plant

A static mixer in the exhaust emission control system of an excess-air-operated combustion engine is formed of an expanded grid with a plurality of openings formed between crossbars. Using an expanded grid achieves both good mixing of the exhaust gas with a reducing agent in a short mixing path and properly aligns the exhaust flow.

Expanded grid static mixer

A metering system in a combustion unit having an exhaust-gas chamber and a reducing agent reservoir includes an electrically controllable valve for introducing the reducing agent into the exhaust-gas chamber without using compressed air. The valve has an outlet opening that opens directly into the exhaust-gas chamber. The outlet opening is fluidically connected to the reservoir through the valve. The metering system can be produced with only little technical outlay. The metering system includes a recirculating circuit, and the valve has a holding chamber for the reducing agent. The holding chamber is disposed downstream of the outlet opening in a reducing agent flow direction, and is fluidically connected into the recirculating circuit. The metering system includes a coolant circuit for cooling the valve. The valve and its outlet opening is disposed in the exhaust-gas chamber to position the principal axis of the valve at an angle of less than 90&deg; with respect to a principal direction of flow of exhaust gas in the exhaust-gas chamber. The metering system includes a baffle disposed in the exhaust-gas chamber to cause a change in direction of reducing agent introduced therein. The combustion unit can be a diesel engine, and the reducing agent can be a urea solution.

Metering system

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 configuration for decomposing nitrogen oxides in a gas stream includes a plurality of catalytic converters disposed one after the other through which the gas stream can flow. Each of the catalytic converters has a honeycomb structure with many parallel cells through which the gas stream can flow. Each of the catalytic converters also has a predetermined cell density and a predetermined average level of activity defined as a proportion by weight of the catalytically active agent. The predetermined cell density of a second catalytic converter through which the gas stream flows after a first catalytic converter is lower than the predetermined cell density of the first catalytic converter. The predetermined average level of activity of the second catalytic converter is also higher than the predetermined average level of activity of the first catalytic converter. The configuration is preferably used in conjunction with an exhaust gas from a combustion drive unit.

Configuration for decomposing nitrogen oxides in a gas stream and method for using the configuration

Process and device for the catalytic cleaning of the exhaust gas from a combustion plant

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 injection device for a reducing agent, a mixing device and a catalyst device are provided in an exhaust pipe. The mixing device is disposed upstream of the injection device as seen in the direction of flow of the exhaust gas. An exhaust gas inlet pipe is connected to the exhaust pipe along the main axis of the exhaust pipe. A first level of the catalyst device may advantageously be a hydrolysis-catalyst module, while the other levels may be SCR catalyst modules.

Exhaust emission control system for the exhaust gas of a diesel engine

A method and a device for controlling a combustion system, in particular an internal combustion engine, and for catalytic cleaning of exhaust gases, as well as a combustion system, catalytically remove a noxious substance from the exhaust gas with the aid of a fluid which is added in a metered manner to the noxious substance. A desired value for a mass flow of the noxious substance in the exhaust gas is prescribed in order to control the combustion system. In this way, the metered addition of the fluid in accordance with the mass flow of the noxious substance is substantially simplified.

Method and device for controlling a combustion system and for catalytic cleaning of exhaust gas, and combustion system

A device for introducing a liquid reducing agent into an exhaust gas purification system includes a gas line for receiving and carrying a gas, a reducing agent line for receiving and carrying a liquid reducing agent, a mixing chamber for mixing the reducing agent with the gas, the mixing chamber fluidically connected to the gas line and to the aid reducing agent line, a metering valve disposed in the reducing agent line; and a control device for controlling a pressure in the reducing agent line dependent upon a gas pressure in the gas line. The control device can also be used for controlling the reducing agent throughput in the reducing agent line in dependence on the gas pressure in the gas line.

Device for introducing a liquid reducing agent into an exhaust gas purification system

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.

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Michelau, Germany

Wieland Mathes