Method and device for the catalytic reduction of nitrogen oxides contained in the off-gas from a combustion system
AssigneeSiemens Aktiengesellschaft
InventorsLothar Hofmann, Günther Pajonk, Manfred Weigl, Gerhard Wissler
Life of this patent
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Abstract
To ensure the maximum possible conversion of nitrogen oxides in a DeNOx 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.
Claims15
A method for a catalytic reduction of nitrogen oxides contained in a medium flow output from a combustion system, which comprises the steps of:
- channeling an off-gas towards and through a catalytic converter;
- metering a reducing agent solution into the off gas before it flows through the catalytic converter;
- determining an amount of dissolved reducing agent to be metered per unit time according to demand;
- and
- using a density of the reducing agent solution to determine a volume of the reducing agent solution to be metered per unit time.
A device for catalytically reducing nitrogen oxides contained in an off-gas output from a combustion system, comprising:
- an off-gas line to be connected to the combustion system for receiving the off-gas;
- a catalytic converter disposed in said off gas line;
- a reservoir for holding a reducing agent solution;
- a metering device connected to said reservoir and to said off-gas line for metering the reducing agent solution into the off-gas;
- and
- a regulating system connected to said metering device and configured to meter a volume of the reducing agent solution according to demand, taking into account a density of the reducing agent solution.
Dependencies are inferred from the claim text.