Gas phase reactor and process for reducing nitrogen oxide in a gas stream
OwnerErwin M.J. Platvoetinventor
Life of this patent
Estimating the term…
Abstract
A 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. 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. A burner is employed to raise the temperature of the inlet gas stream. A heat exchanger is used to transfer heat from treated gas to the inlet gas. Optionally, a deflector is used to deflect gas flow through the heat exchanger.
Claims37
A 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 proximal end, a distal end, and an axis defining a longitudinal direction, a gas stream inlet at the proximal end for receiving an inlet gas stream 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) an injector for introducing a reducing agent into the inlet gas stream;
- c) a burner positioned in the reactor shell for heating the inlet gas stream to a reaction temperature;
- d) a catalyst bed within the shell and positioned downstream of the burner, 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 provide a treated gas of reduced nitrogen oxide concentration;
- and,
- e) means positioned upstream of the burner for effecting heat exchange between the treated gas and the inlet gas stream containing reducing agent.
A method for the selective catalytic reduction of nitrogen oxide in a gas which comprises:
- a) introducing a reducing agent into a gas stream containing nitrogen oxide;
- b) in a first heating step, passing the gas stream with the reducing agent through a heat exchanger;
- c) in a second heating step, raising the temperature of the gas stream with the reducing agent to a reaction temperature sufficient for the catalyzed reduction of nitrogen oxide with the reducing agent;
- e) passing the gas stream with the reducing agent through a catalyst bed containing at least one nitrogen oxide conversion catalyst effective for the selective catalytic reduction of nitrogen oxide in the presence of the reducing agent to produce a treated gas;
- and,
- f) passing the treated gas through the heat exchanger to transfer heat from the treated gas to the gas stream with the reducing agent.
Dependencies are inferred from the claim text.