Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Waste gas purifier
Reexamination Certificate
2001-02-26
2003-12-16
Tran, Hien (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Waste gas purifier
C422S172000, C422S173000, C422S176000, C422S180000, C422S181000
Reexamination Certificate
active
06663839
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention herein relates to a chemical reactor and method for catalytically reducing the content of nitrogen oxide in a gas, particularly flue or stack gas, resulting from the combustion of fuel.
2. Description of the Related Art
The combustion of fuels in various industrial processes often generates undesirable SO oxides of nitrogen (NO
x
) usually in the form of nitric oxide (NO) and nitrogen dioxide (NO
2
). High combustion temperatures tend to produce more NO
x
. Because NO
x
is harmful to the environment, efforts have been made to reduce the emission of NO
x
in gases produced by industrial processes involving the combustion of fuel, particularly gases resulting from the operation of power plants, thermal cracking furnaces, incinerators, internal combustion engines, metallurgical plants, fertilizer plants and chemical plants.
Methods for selectively reducing the NO
x
content of a flue gas are known. Generally, such methods involve the reaction of NO
x
with a reducing agent, optionally in the presence of a catalyst. The selective non-catalytic reduction (“SNCR”) of NO
x
with a reducing agent such as ammonia or urea requires a relatively high temperature, e.g., in the range of from about 1600° F. to about 2100° F.
Alternatively, the reduction of NO
x
with ammonia can be performed catalytically at a much lower temperature, e.g. from about 500° F. to about 950° F., in a process known as selective catalytic reduction (“SCR”).
One problem associated with the treatment of flue gas using conventional SCR methods and apparatus is that the weight and bulk of the equipment necessary to achieve satisfactory removal of NO
x
requires that it be located at ground level. Many industrial plants need to be retrofitted with NO, removal (“deNOx”) equipment in order to meet the requirements of more stringent government regulations. However, because of the physical bulk of the deNOx system, the flue gas must be diverted to ground level for treatment and then sent back into a stack for subsequent exhaust to the atmosphere. To avoid the large cost of such a system it would be highly advantageous to provide a relatively lightweight deNOx unit which can be incorporated directly into the stack.
SUMMARY OF THE INVENTION
In accordance with the present invention, a radial flow gas phase reactor is provided for the chemical conversion of nitrogen oxide in a gas stream and comprises:
a) a shell having interior and exterior surfaces, a gas stream inlet 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) 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 passageway and an outer wall spaced apart from the interior surface of the reactor shell; and,
d) an inlet gas stream deflector for directing the flow of inlet gas containing reducing agent radially through the catalyst bed, the treated gas emerging from its radial passage through the catalyst bed and exiting from the reactor shell through the gas stream outlet.
The radial flow reactor of this invention provides a relatively lightweight unit for the selective catalytic reduction of NO
x
in a gas, in particular flue gas produced by the combustion of a fossil fuel in a furnace, and is readily incorporated into furnaces equipped with stacks of conventional design, thus lending itself well to retrofit installation in existing units.
REFERENCES:
patent: 2472254 (1949-06-01), Johnson
patent: 3041149 (1962-07-01), Houdry
patent: 3380810 (1968-04-01), Hamblin
patent: 3594131 (1971-07-01), De Palma et al.
patent: 3730691 (1973-05-01), Lang et al.
patent: 3733181 (1973-05-01), Tourtellotte et al.
patent: 3887683 (1975-06-01), Abe et al.
patent: 4160009 (1979-07-01), Hamabe
patent: 4160805 (1979-07-01), Inaba et al.
patent: 4199554 (1980-04-01), Araki et al.
patent: 4246234 (1981-01-01), Kittrell et al.
patent: 4283368 (1981-08-01), Harada et al.
patent: 4302431 (1981-11-01), Atsukawa et al.
patent: 4405562 (1983-09-01), Zardi et al.
patent: 4457895 (1984-07-01), Prigent
patent: 4478793 (1984-10-01), Vickers
patent: 4576799 (1986-03-01), Wörner et al.
patent: 4602673 (1986-07-01), Michelfelder et al.
patent: 4678643 (1987-07-01), Fetzer
patent: 4682470 (1987-07-01), Shaff
patent: 4725416 (1988-02-01), Kristof et al.
patent: 4726935 (1988-02-01), Inatsune et al.
patent: 4732743 (1988-03-01), Schmidt et al.
patent: 4739826 (1988-04-01), Michelfelder et al.
patent: 4820492 (1989-04-01), Wada et al.
patent: 4828806 (1989-05-01), Flockenhaus et al.
patent: 4830833 (1989-05-01), Shaff
patent: 4867953 (1989-09-01), Riekert et al.
patent: 4880378 (1989-11-01), Hums
patent: 4903755 (1990-02-01), Michelfelder et al.
patent: 4916107 (1990-04-01), Brand et al.
patent: 4950473 (1990-08-01), Flockenhaus et al.
patent: 4961917 (1990-10-01), Byrne
patent: 5047220 (1991-09-01), Polcer
patent: 5078973 (1992-01-01), Kuroda et al.
patent: 5104629 (1992-04-01), Dreschler
patent: 5108717 (1992-04-01), Deller et al.
patent: 5139757 (1992-08-01), Topsoe
patent: 5145652 (1992-09-01), Veser et al.
patent: 5149884 (1992-09-01), Brenner et al.
patent: 5155083 (1992-10-01), Yoshida et al.
patent: 5233934 (1993-08-01), Krigmont et al.
patent: 5318755 (1994-06-01), Kuivalainen et al.
patent: 5358698 (1994-10-01), Butler et al.
patent: 5380499 (1995-01-01), MacInnis
patent: 5401479 (1995-03-01), Matros et al.
patent: 5437851 (1995-08-01), MacInnis
patent: 5466421 (1995-11-01), Deller et al.
patent: 5474751 (1995-12-01), Sigling et al.
patent: 5531968 (1996-07-01), Steenackers
patent: 5567392 (1996-10-01), Becker et al.
patent: 5575980 (1996-11-01), Turek
patent: 5593645 (1997-01-01), Steenackers et al.
patent: 5603909 (1997-02-01), Varner et al.
patent: 5645803 (1997-07-01), Steenackers et al.
patent: 5678625 (1997-10-01), Schlüter et al.
patent: 5694869 (1997-12-01), Breen et al.
patent: 5728356 (1998-03-01), Iida et al.
patent: 5738024 (1998-04-01), Winegar
patent: 5756059 (1998-05-01), Zamansky et al.
patent: 5809776 (1998-09-01), Holtermann et al.
patent: 5814284 (1998-09-01), Schlüter
patent: 5817282 (1998-10-01), Radlein et al.
patent: 5820838 (1998-10-01), Tsuo et al.
patent: 5827485 (1998-10-01), Labal et al.
patent: 5918555 (1999-07-01), Winegar
patent: 5985222 (1999-11-01), Sudduth et al.
patent: 5988115 (1999-11-01), Anderson et al.
patent: 6019068 (2000-02-01), Tsuo et al.
patent: 6048510 (2000-04-01), Zauderer
patent: 6066303 (2000-05-01), Sudduth et al.
patent: 6080376 (2000-06-01), Iida et al.
patent: 197 20 205 (1998-11-01), None
patent: WO 98/03249 (1998-01-01), None
patent: WO 00/53904 (2000-09-01), None
Hopkins Steven M.
Platvoet Erwin M. J.
ABB Lummus Global Inc.
Dilworth & Barrese LLP
Tran Hien
LandOfFree
Radial flow gas phase reactor and method for reducing the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radial flow gas phase reactor and method for reducing the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radial flow gas phase reactor and method for reducing the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3164019