Radial flow gas phase reactor and method for reducing the nitrogen oxide content of a gas
AssigneeABB Lummus Global Inc.
InventorsErwin M. J. Platvoet, Steven M. Hopkins
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Abstract
A radial flow gas phase reactor for the selective catalytic reduction of nitrogen oxide in a gas stream includes a shell enclosing an interior space in which is located at least one catalyst bed containing a catalyst for the selective conversion of NOx. A deflector directs the flow of gas radially through the bed. An injector upstream of the catalyst introduces a reducing agent such as ammonia into the inlet gas stream. The catalyst bed can include particulate, monolith, or microengineered catalyst.
Claims15
In a combustion system including a furnace containing a combustion zone and a stack positioned above the combustion zone, an improvement comprising a radial flow gas phase reactor for the chemical conversion of nitrogen oxide in a gas stream which comprises:
- a) a shell having interior and exterior surfaces, a gas stream inlet for receiving an inlet gas stream discharged from the combustion zone and having an initial concentration of nitrogen oxide and a gas stream outlet through which treated gas of reduced nitrogen oxide concentration relative to the nitrogen oxide concentration of the inlet gas stream is discharged;
- b) at least one injector for introducing reducing agent into the inlet gas stream;
- c) at least one catalyst bed within the shell positioned therein at a location which is approximately at, or downstream of, the injector, the catalyst bed containing at least one nitrogen oxide conversion catalyst for the selective catalytic reduction of nitrogen oxide in the inlet gas stream to produce a treated gas of reduced nitrogen oxide concentration, the catalyst bed having an interior wall defining an axial first passageway and an outer wall spaced apart from the interior surface of the reactor shell defining a circumferential second passageway;
- and,
- d) an inlet gas stream deflector for directing the flow of inlet gas containing reducing agent radially through the catalyst bed between the axial first passageway and the circumferential second passageway to produce the treated gas,
- wherein the reactor is positioned in the stack above the combustion zone.
Dependencies are inferred from the claim text.