Reduction of nitrogen oxide in effluent gases using formaldehyde and/or formaldehyde-derived free radicals
A process is described for reducing the nitrogen oxide content of a gas wherein the temperature of the gas varies which comprises alternately, contacting the gas with (A) formaldehyde when the gas is at a temperature which is sufficient to promote the reaction of formaldehyde with the nitrogen oxide in the gas and to reduce the nitrogen oxide content in the gas to a desired level, and (B) free radicals derived by reacting formaldehyde with nitrogen or nitric oxide in the presence of a catalyst wherein the free radicals are capable of reacting with nitrogen oxide when the temperature of the gas is lower than the temperature in (A) and the reaction with formaldehyde does not reduce the nitrogen oxide content to the desired level, whereby the nitrogen oxide content of the gas is reduced to the desired level.
- Assignee:
- Molecular Technology Corp., Canton, OH (United States)
- Patent Number(s):
- US 5234671; A
- Application Number:
- PPN: US 7-725558
- OSTI ID:
- 6250989
- Country of Publication:
- United States
- Language:
- English
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54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION CONTROL
ALDEHYDES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
DENITRIFICATION
ELEMENTS
FLUE GAS
FORMALDEHYDE
GASEOUS WASTES
NITRIC OXIDE
NITROGEN
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
RADICALS
WASTES