Controlled spectrum ultraviolet radiation pollution control process
AssigneeDana UV, Inc.
InventorsJames T. Leach, Michael Lee Fraim
Life of this patent
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Abstract
A method for reducing or substantially eliminating oxides of nitrogen from an effluent gas stream, that includes providing a source of ultraviolet radiation with a precise wavelength, adding ammonia or an ammonia based reagent to the effluent stream, upstream of the ultraviolet radiation source, controllably operating the ultraviolet radiation source to irradiate the effluent stream flowing in the duct and substantially reducing or eliminating oxides of nitrogen by promotion a reaction of ammonia with the oxides of nitrogen to produce N2 and H2O, and also thereby destroying any surplus ammonia. This process can also be modified to oxidize carbon monoxide and VOC's to CO2 and H2O.
Claims40
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and controlling the rate of ammonia or ammonia based reagent added to said stream including measuring upstream NOx and downstream NOx and/or NH3 slip.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and including effecting dissociation of virtually all of the ammonia and producing a purified effluent stream that contains an insignificant amount of residual ammonia.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and including controlling the volumetric flux of UV radiation in response to measuring/sampling upstream NOx and downstream NOx and NH3 slip and in response to measuring actual UV flux in the reaction zone.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and including employing a two stage retrofit or technology transition system for reducing NOx levels, where the first stage is a conventional NSCR, SCR or SHR system and the second stage is a SUVR system with ultraviolet elements acting to polish the ammonia and NOx slip to below 1 ppm.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and wherein the radiation source is provided in the form of elongated tubular emitters spaced apart and located in an orientation with respect to the velocity vector of the effluent stream, whereby the pollutant gases flowing around the emitters are treated uniformly and completely.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and wherein a radiation source is provided in the form of one or more LED arrays producing the effective wavelength and intensity of radiation.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and wherein the tubular emitters are located around the perimeter of a duct passing said flow stream.
The method of controlling the wavelength and the volumetric flux intensity of an SUVR process to reduce or substantially eliminate unburned hydrocarbons or volatile organic compounds, VOC's, (CxHyOz) including carbon monoxide (CO) and halogenated VOC's (CxHy(F,Cl,Br,I)z) from effluent gas streams that contain oxygen gas (O2) and water vapor (H2O) by reacting these species with oxygen based radicals (O*, O2−, HO2*, OH*) to form to carbon dioxide (CO2) and water vapor (H2O), the method including:
- a) providing a source of ultraviolet radiation with output between 172 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) providing a source of electrons with energies of 4 eV or greater, derived from a corona discharge or electron beam,
- c) causing said ultraviolet radiation, or electron source, to achieve intensity flux sufficient to dissociate the water molecule (H2O) and the oxygen molecule (O2) to oxygen based radicals (O*, O2−, HO2*, OH*) and to excite VOC molecules (CxHyOz) to expedite the oxidation reaction and dissociate halogenated VOC's (F,Cl,Br,I) to form halogen acids,
- d) and including removing halogen acids (HF, HCl, HBr, or HI) and sulfuric acid (H2SO4) generated in the oxidation process down stream by converting them to an ammonium salt or salts, the method using wet or dry electrostatic precipitation, or by absorbing the halogen acid in an aqueous solution containing a base metal (Na, Ca, Mg, K, etc.) or by absorption on a filter impregnated with activated carbon and/or calcium or magnesium oxide.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and including embodying the UV source in a mobile device that is self contained and includes a circulation fan and particulate matter filter, for use in areas where people are present and where the VOC's may present a potential health or safety hazard, and wherein the ultraviolet source optionally has two zones;
- the first zone for making oxygen based free radicals and ozone, and the second stage for ozone and chlorine gas destruction.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) including providing an electrostatic precipitator and operating said source of ultraviolet radiation in series with said precipitator.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and wherein said source of ultraviolet radiation comprises multiple UV bulbs, which are spaced apart in the path of said effluent stream, and providing chevron shaped elements in said path directly upstream of said bulbs to protect the bulbs from erosion from effluent particles impact.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) and wherein said source of ultraviolet radiation comprises one or more UV bulbs, and including the step of flowing particle free gas adjacent the bulb or bulbs as a protection from erosion due to effluent particle impact.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 am associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) including converting ammonia to amidogen radical or radically for injection into the effluent stream.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) including providing a combustion process stack, wherein said effluent stream flows, during stream irradiation.
The SUVR method for reducing or substantially eliminating oxides of nitrogen (NOx) from an effluent gas stream between 300-800° K and that contains oxygen gas (O2) by reacting NOx with the amidogen radical (NH2*) to form to harmless nitrogen gas (N2) and water vapor (H2O), the method including the steps:
- a) providing a source of ultraviolet radiation with output between 180 nm and 220 nm associated with a duct containing the effluent stream, or streams,
- b) mixing ammonia or an ammonia-based reagent with said stream, upstream of said ultraviolet radiation source so that the variance is within +15%/−5% of stoichiometric concentration,
- c) causing said ultraviolet radiation source to irradiate the stream with effective wavelength band and intensity flux sufficient to dissociate the ammonia molecules (NH3) to the amidogen radicals (NH2*) and to excite and dissociate NOx molecules to promote the (NO+NH2*) to (N2+H2O) reduction reaction,
- d) including removing one of the following from the effluent stream prior to said irradiation:
- x1) particulate
- x2) aerosols
- x3) VOCs.
Apparatus for reducing or substantially eliminating oxides of nitrogen from a hot effluent gas stream, that comprises:
- a) a duct and a source of ultraviolet radiation associated with said duct passing said effluent stream,
- b) means for adding ammonia or amidogen radicals to said stream, upstream of said ultraviolet radiation source, and
- c) means for controllably operating said ultraviolet radiation source to irradiate said stream flowing in the duct, to effect reduction or substantial elimination of said oxides of nitrogen by promoting, reaction of ammonia with said oxides of nitrogen, to produce N2 and H2O flowing in the stream,
- d) and wherein said source of ultraviolet radiation comprises UV emitting means extending in generally clustered relation.
A method for reducing or substantially eliminating oxides of nitrogen from a hot effluent gas stream, that includes
- a) providing a clustered source of ultraviolet radiation less than about 220 nanometers and associated with a duct passing said effluent stream,
- b) adding ammonia to said stream, upstream of said ultraviolet radiation source,
- c) controlling the rate of ammonia addition to said stream and controllably operating said ultraviolet radiation source to irradiate said stream flowing in the duct, to effect reduction or substantial elimination of said oxides of nitrogen by promoting reaction of ammonia with said oxides of nitrogen, to produce N2 and H2O flowing in the stream.
Dependencies are inferred from the claim text.