Siemens Aktiengesellschaft

Siemens Aktiengesell Schaft

Argillon Gmbh

Lothar Hofmann

Wieland Mathes

Manfred Weigl

Gerhard Wissler

G&uuml;nther Pajonk

Ronald Neufert

Udo Klumpp

Kurt Schardt

Raimund M&uuml;ller

Erwin Achleitner

Ralf Dotzel

Klaus Wenzlawski

Jörg Werner Münch

Frank Witzel

Rainer Tost

Winfried D&ouml;lling

Dietmar Weisensel

Klaus Rusch

Detlev Schoppe

Oliver Pfaff

Winfried Doelling

Dagmar Schobert-Schaefer

The invention relates to an extruded solid catalyst body for breaking down nitrogen oxides in the presence of a reducing agent as well as to a process for manufacture of said body. The solid catalyst body has an active material that contains 60 to 87% by weight of an ion-exchanged zeolite containing at least one metal from the group containing Cu, Hf, La, Au, In, V, lanthanoids and transition metals of group VIII of the periodic system, more than 10 to 37% by weight of aluminum oxide and 2 to 10% by weight of inorganic fibers. The solid catalyst body, the active material of which contains a zeolite can be manufactured by extrusion and has a high degree of mechanical stability at a high catalytic activity.

Extruded monolithic catalytic converter and manufacturing method

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 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

A method is provided for the catalytic conversion of nitrogen oxides contained in the exhaust gas of an internal combustion engine. A reducing agent is added in a controlled manner upstream of a denitrification catalyst, as seen in exhaust gas flow direction, and in dependence on a nitrogen oxide concentration. The reducing agent is added in a superstoichiometric amount in relation to the nitrogen oxide content if an operating parameter and/or a value derived from the operating parameter falls below or exceeds a threshold value. The addition of the reducing agent is then terminated or continued in a substoichiometric manner. The invention provides a measure for obtaining an extremely high average nitrogen oxide conversion, especially under varying operating conditions of the internal combustion engine.

Method for the catalytic conversion of nitrogen oxides contained in the exhaust gas of an internal combustion engine

A microwave hydrolysis reactor for converting urea into ammonia has one or more reaction chambers into which a urea solution is fed via a feed device and a discharge device for discharging an ammonia-water mixture. A catalytic converter is arranged in the reaction chamber. A microwave-transmitting device allows irradiating so that energy is fed to the urea solution in the reaction chamber.

Process for converting urea into ammonia

To ensure the maximum possible conversion of nitrogen oxides in a DeNO catalytic converter in an off-gas cleaning installation for reducing nitrogen oxides and, at the same time, to prevent the reducing agent which is used for the reduction from escaping into the environment, there is provision for the density of a reducing agent solution to be used to determine the volume of the reducing agent solution which is to be metered. The density is regulated in two ways, in that the temperature of the reducing agent solution is measured using a temperature sensor and set by a temperature-control device.

Method and device for the catalytic reduction of nitrogen oxides contained in the off-gas from a combustion system

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

When determining the amount of a reducing agent solution to be introduced into the exhaust gas of a combustion system, in particular of a diesel engine, for catalytically reducing the nitrogen oxides by the SCR process, the concentration of the reducing agent in the reducing agent solution as well as the parameters characterizing the operating state of the combustion system, the exhaust gas and/or the catalyst are taken into consideration. As a result, the safety margin with respect to a theoretically optimum amount to be introduced that is required to avoid a leakage of reducing agent can be reduced, whereby the conversion rate of the nitrogen oxides is improved.

Method and device for reducing the nitrogen oxides in the exhaust gas of a combustion system

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 tank for a vehicle having a selective catalytic reduction exhaust gas purification system operating with a reducing agent includes a fuel space for the vehicle fuel and a reducing agent space for the reducing agent. The fuel space and the reducing agent space are combined into a single structural that can be fastened as a whole to the vehicle by brackets on the structural unit. This utilizes the limited space available in any vehicle as efficiently as possible and eliminates the need to provide mounting arrangements for separate fuel and reducing agent tanks.

Growing community of inventors

Altenkunstadt, Germany

Lothar Hofmann