U.S. patent application number 11/148047 was filed with the patent office on 2006-12-14 for nox reduction system and method.
Invention is credited to Ralph Slone.
Application Number | 20060277897 11/148047 |
Document ID | / |
Family ID | 37522849 |
Filed Date | 2006-12-14 |
United States Patent
Application |
20060277897 |
Kind Code |
A1 |
Slone; Ralph |
December 14, 2006 |
NOx reduction system and method
Abstract
A system for reduction of noxious oxides from an exhaust of an
internal combustion engine. The internal combustion engine includes
an engine exhaust. A NOx catalytic reactor has at least one inlet
in communication with the engine exhaust. A reductant catalytic
reactor includes an inlet in communication with a reductant fuel
supply, and an outlet in communication with at least one inlet to
the NOx catalytic reactor.
Inventors: |
Slone; Ralph; (Columbus,
IN) |
Correspondence
Address: |
TAYLOR & AUST, P.C.
142 SOUTH MAIN STREET
P. O. BOX 560
AVILLA
IN
46710
US
|
Family ID: |
37522849 |
Appl. No.: |
11/148047 |
Filed: |
June 8, 2005 |
Current U.S.
Class: |
60/286 ; 60/295;
60/301 |
Current CPC
Class: |
F01N 2240/30 20130101;
Y02T 10/12 20130101; F01N 2610/10 20130101; Y02T 10/24 20130101;
F01N 2510/063 20130101; F01N 2610/04 20130101; F01N 3/206
20130101 |
Class at
Publication: |
060/286 ;
060/295; 060/301 |
International
Class: |
F01N 3/00 20060101
F01N003/00; F01N 3/10 20060101 F01N003/10 |
Claims
1. A system for reduction of noxious oxides from an exhaust of an
internal combustion engine, comprising; an internal combustion
engine including an engine exhaust; a NOx catalytic reactor having
at least one inlet in communication with said engine exhaust; a
reductant fuel supply; a reductant catalytic reactor including an
inlet in communication with said reductant fuel supply and an
outlet in communication with said at least one inlet to said NOx
catalytic reactor, said reductant catalytic reactor not directly
connected to the atmosphere and operating without ambient air being
introduced directly thereto: a heater in communication with said
reductant catalytic reactor inlet whereby said fuel supply is
heated prior to entering the reductant catalytic reactor, and,
wherein said reductant catalytic reactor comprises one of a
zeolites and precious metals.
2. The system for reduction of noxious oxides of claim 1, further
including a pump in communication with and between said reductant
fuel supply and said reductant catalytic reactor.
3. The system for reduction of noxious oxides of claim 2, further
including a regulator for controlling fluid flow through said
pump.
4. The system for reduction of noxious oxides of claim 2, wherein
said heater is in communication with and between said pump and said
reductant catalytic reactor.
5. The system for reduction of noxious oxides of claim 4, wherein
said heater heats reductant fuel from said reductant fuel supply to
a temperature of between approximately 450 to 600 degF.
6. A system for reduction of noxious oxides from an exhaust of an
internal combustion engine, comprising; an internal combustion
engine including an engine exhaust; a NOx catalytic reactor having
at least one inlet in communication with said engine exhaust; a
reductant fuel supply; a reductant catalytic reactor including an
inlet in communication with said reductant fuel supply and an
outlet in communication with said at least one inlet to said NOx
catalytic reactor, said reductant catalytic reactor not directly
connected to the atmosphere and operating without ambient air being
introduced directly thereto; a heater in communication with said
reductant catalytic reactor inlet whereby said fuel supply is
heated prior to entering the reductant catalytic reactor, and,
wherein said NOx catalytic reactor includes a ceramic catalyst
material comprised of Al.sub.20.sub.3, doped with one of Na, Zr and
La.
7. A system for reduction of noxious oxides from an exhaust of an
internal combustion engine, comprising; an internal combustion
engine including an engine exhaust; a NOx catalytic reactor having
at least one inlet in communication with said engine exhaust; a
reductant fuel supply; a reductant catalytic reactor including an
inlet in communication with said reductant fuel supply and an
outlet in communication with said at least one inlet to said NOx
catalytic reactor, said reductant catalytic reactor not directly
connected to the atmosphere and operating without ambient air being
introduced directly thereto; a heater in communication with said
reductant catalytic reactor inlet whereby said fuel supply is
heated prior to entering the reductant catalytic reactor, and,
wherein said NOx catalytic reactor includes a ceramic catalyst
material comprised of Y zeolite, doped with Na.
8. (canceled)
9. The system for reduction of noxious oxides of claim 1, wherein
said reductant catalytic reactor is doped with at least one of Mo,
Ti and Fe.
10. The system for reduction of noxious oxides of claim 9, wherein
said reductant fuel supply can be any one of diesel fuel, gasoline
and one or more other hydrocarbons.
11. The system for reduction of noxious oxides of claim 9, wherein
said internal combustion engine utilizes fuel in the form of at
least one of diesel, natural gas, gasoline, coal, and alcohol.
12. A system for reduction of noxious oxides from an exhaust of an
internal combustion engine, comprising; a NOx catalytic reactor
having at least one inlet configured for communication with said
engine exhaust; a reductant fuel supply; a reductant catalytic
reactor including an inlet in communication with said reductant
fuel supply and an outlet in communication with said at least one
inlet to said NOx catalytic reactor, said reductant catalytic
reactor not directly connected to the atmosphere and operating
without ambient air being introduced directly thereto; a heater in
communication with said reductant catalytic reactor inlet whereby
said fuel supply is heated prior to entering the reductant
catalytic reactor; and, said reductant catalytic reactor operating
with said fuel supply in the absence of water being provided
thereto.
13. The system for reduction of noxious oxides of claim 12, further
including a pump in communication with and between said reductant
fuel supply and said reductant catalytic reactor.
14. The system for reduction of noxious oxides of claim 13, further
including a regulator for controlling fluid flow through said
pump.
15. The system for reduction of noxious oxides of claim 13, wherein
said heater is in communication with and between said pump and said
reductant catalytic reactor.
16. The system for reduction of noxious oxides of claim 12, wherein
said reductant catalytic reactor includes at least one of zeolites,
silica aluminas, dispersed precious metals on monolith, and
aluminum trioxide.
17. The system for reduction of noxious oxides of claim 16, wherein
said reductant catalytic reactor is doped with at least one of
these metals Mo, Ti and Fe.
18. A method of reducing noxious oxides from an exhaust of an
internal combustion engine, comprising the steps of: heating a
reductant fuel; at least one of cracking and reforming a said
reductant fuel in the absence of ambient air in a reductant
catalytic reactor comprising one of a zeolites and precious metals;
mixing the at least one of cracked and reformed reductant fuel with
exhaust gas from the internal combustion engine; and catalytically
converting the mixed reductant fuel and exhaust gas in a NOx
catalytic reactor.
19. The method of reducing noxious oxides of claim 18, wherein said
reductant fuel comprises any one of diesel fuel, gasoline and one
or more other hydrocarbons prior to being at least one of cracked
and reformed.
20. (canceled)
21. The method of reducing noxious oxides of claim 18, wherein said
reductant catalytic reactor is doped with at least one of Mo, Ti
and Fe.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a system and method for
reducing noxious oxides from an exhaust gas of an internal
combustion engine, and, more particularly, to such a system and
method using a catalytic process.
[0003] 2. Description of the Related Art
[0004] Noxious oxides (NOx) has been the subject of air pollution
regulations and control efforts for over 30 years. These efforts
began in southern California, but under the direction of the U.S.
Environmental Protection Agency (EPA), NOx control efforts are
spreading throughout the U.S. and to many major cities worldwide.
Increasingly stringent control efforts continue to be mandated by
regulatory bodies, both domestically and internationally. In
southern California and other areas of the U.S. (representing over
60% of the population) that have not attained EPA's ambient air
quality standards, an active trading market exists for NOx
"credits", which have economic value and can be created when
controls are installed whose performance exceeds regulatory
requirements.
[0005] Emission standards in the U.S. will require reduction of
diesel emissions for transportation vehicles (light and heavy-duty
diesel powered trucks and buses) by as much as 90% from current
levels in the 2005-2010 time frame. In addition, emissions levels
for boilers-electric generators (especially coal fired boilers) and
internal combustion (IC) engine (gas and diesel) powered electric
generators are required to meet even more stringent NOx emissions
levels. Achieving these levels with acceptable costs and durability
will be very difficult for these industries.
[0006] NOx reduction approaches presently being developed may
present problems and difficulties. Catalyst poisoning, thermal
cycling and supplying a practical reductant make the performance
and life of NOx adsorbers and lean NOx catalysts problematic.
Selective Catalytic Reduction (SCR) requires an external fluid be
distributed and carried on commercial vehicles. Combustion control
technologies such as Exhaust Gas Recirculation, high injection
pressures, variable geometry turbines for air handing and other
similar mechanisms used to control NOx emissions from diesel
engines add complexity and cost.
[0007] What is needed in the art is a NOx reduction system and
method which is simpler and does not require an additional fluid
(reductant) source on board moving vehicles.
SUMMARY OF THE INVENTION
[0008] The present invention provides a system for reduction of
noxious oxides including an additional reductant catalytic reactor
providing a catalyzed reductant fuel to a NOx catalytic
reactor.
[0009] The invention comprises, in one form thereof, a system for
reduction of noxious oxides from an exhaust of an internal
combustion engine. The internal combustion engine includes an
engine exhaust. A NOx catalytic reactor has at least one inlet in
communication with the engine exhaust. A reductant catalytic
reactor includes an inlet in communication with a reductant fuel
supply, and an outlet in communication with at least one inlet to
the NOx catalytic reactor.
[0010] An advantage of the present invention is that a higher NOx
reduction is effected (based on the chemical stability/sulfur
resistance of the catalyst used) in the exhaust from a diesel
engine burning high sulfur diesel fuel.
[0011] Another advantage is that one liquid can be used for fuel
and to catalytically generate the NOx reductant.
[0012] Yet another advantage is that the system is thermally and
chemically stable.
[0013] Still another advantage is that the system uses only about
3% of the system total fuel for NOx reduction.
[0014] A further advantage is that the NOx catalyst, constituting
the bulk of the system's catalysts, does not use precious metal
catalysts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of an embodiment of the invention
taken in conjunction with the accompanying drawings, wherein:
[0016] FIG. 1 is a schematic view of an embodiment of the NOx
reduction system of the present invention; and
[0017] FIG. 2 is graphical representation of NOx reduction which
may be achieved using the NOx reduction system shown in FIG. 1.
[0018] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplification set out
herein illustrates one preferred embodiment of the invention, in
one form, and such exemplification is not to be construed as
limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring now to the drawings, and more particularly to FIG.
1, there is shown an embodiment of a system 10 for reduction of NOx
from an exhaust 12 of an internal combustion engine 14. System 10
also generally includes a NOx catalytic reactor 16, reductant fuel
supply 18 and reductant catalytic reactor 20.
[0020] Reductant fuel supply 18 contains diesel fuel, gasoline
and/or one or more other hydrocarbons. In one embodiment, reductant
fuel supply 18 is the same fuel tank which supplies fuel to IC
engine 14, and thus reductant fuel 22 within reductant fuel supply
18 is also the same as the fuel supplied to IC engine 14 (e.g.,
diesel fuel). Configured as such, it will be appreciated that a
separate supply line leads from reductant fuel supply 18 to IC
engine 14. Although the present invention is described and shown
herein with reference to a diesel engine, it should be understood
that the present invention is applicable to any hydrocarbon
combustion source (e.g., diesel, natural gas, gasoline, coal,
alcohols, etc.).
[0021] NOx catalytic reactor 16 has an inlet 24 in communication
with engine exhaust 12, and an outlet 26 in communication with the
ambient environment, and optionally in communication with analyzers
for determining a NOx level within the exhaust.
[0022] In one embodiment, NOx catalytic reactor 16 includes a
ceramic catalyst material comprised of Al.sub.2O.sub.3, doped with
(either integrated into the crystal structure of the
Al.sub.2O.sub.3 or impregnated with) with an alkaline earth element
(Na, Li, K or CS), Zr, Ti, V, Ce or La. In another embodiment, NOx
catalytic reactor 16 includes a ceramic catalyst material comprised
of Y zeolites, doped with (either integrated into the crystal
structure of the zeolite or impregnated with) an alkaline earth
element (Na, Li, K, or CS), Zr, Ti, V or La or Beta zeolites doped
with Fe.
[0023] Reductant catalytic reactor 20 includes an inlet 28 in fluid
communication with reductant fuel supply 18, and an outlet 30 in
communication with inlet 24 to NOx catalytic reactor 16. More
particularly, outlet 30 is coupled with branch exhaust 32 upstream
from inlet 24 to NOx catalytic reactor 16. Gases transported from
outlet 30 of reductant catalytic reactor 20 therefore mix with
engine exhaust gases from exhaust 12, prior to entering NOx
catalytic reactor 16 at inlet 24.
[0024] Pump 34 and coil heater 36 are disposed in a series
arrangement between reductant fuel supply 18 and reductant
catalytic reactor 20. Regulator 38 controls the volumetric fluid
flow through pump 34, and ultimately to reductant catalytic reactor
20. Heater 36 heats the reductant fuel outputted from pump 34 to a
temperature of between approximately 450-600.degree. F., which is
necessary to maintain a minimum temperature required to drive the
reforming/cracking process of the reductant fuel within reductant
catalytic reactor 20.
[0025] Reductant catalytic reactor 20 includes a cracking and/or
reforming catalyst used for reductant formation. In one embodiment,
the cracking and/or reforming catalyst is comprised of zeolites,
silica aluminas, precious metals wash coated on Al203 wash coated
onto extruded corrigated monolith cylinders and/or Al.sub.2O.sub.3
or a combination of these compounds (needed to produce the desired
combination of reductants to optimize NOx reduction at a given
exhaust condition). The zeolites are preferably of ZSM5
configuration with a SiO2 to Al2O3 ratio of from 5-1000. These
zeolites may be used in the pure form or doped with (impregnated or
integrated into the crystal structure) Mo, Ti, Fe. The Silica
Aluminas are solid solutions of SiO2 and Al2O3 oxides that are
doped with Mo, Ti, and/or Fe.
[0026] During use, diesel fuel, gasoline or other hydrocarbons are
catalytically cracked and/or reformed to produce H.sub.2, CO and/or
short chain hydrocarbons (oxidized and partially unsaturated) to
act as reductants for NOx when passed over NOx catalytic reactor 16
in conjunction with the NOx from exhaust 12 originating from IC
engine 14. The cracked and/or reformed reductant fuel is mixed with
the engine exhaust in branch exhaust 32 and transported to inlet 24
of NOx catalytic reactor 16. The equation for the reductant
reaction in NOx catalytic reactor 16 is:
[0027] HC, CO and/or H.sub.2 (one or
all)+NOx=>N.sub.2+CO.sub.2+H.sub.20 (dependent upon the
reductant mix).
[0028] Unlike three-way catalysts used on automobiles for NOx
reduction, system 10 reduces NOx in the presence of high
concentrations of O.sub.2 (less than 1%) and sulfur oxides (less
than 15 ppm) normally found in the exhaust of diesel and lean burn
natural gas/gasoline engine powered vehicles as well as most coal
and natural gas fired boilers.
[0029] System 10 uses a unique cracking/reforming catalyst to
produce a tailored, very active reductant to activate a normally
very thermally and chemically inactive ceramic catalyst to reduce
NOx in the presence of high levels of sulfur oxide and oxygen. This
unique combination of catalysts produces a NOx reduction after
treatment system that is very sulfur tolerant and thermally stable
and cost effective since the NOx catalyst (constituting the bulk of
the system catalyst) does not use precious metals and is very
efficient since it only involves a 2-3 fuel penalty. System 10 has
demonstrated over 90% NOx reduction (FIG. 2) in the exhaust from an
IC engine 14 burning high sulfur (500 ppm) diesel fuel.
[0030] In contrast with conventional systems, the present invention
catalytically and thermally produces, under controlled conditions,
taylored reductants from commercially available hydrocarbons (such
as diesel fuel and gasoline) that will cause materials that are not
normally able to (or catalytically active for) effectively reduce
the oxides of nitrogen from the exhausts of combustion sources.
These normally inactive materials are preferably ceramics and are
very stable thermally and chemically (are not poisoned by active
compounds in the exhaust such as SOx) giving these materials the
double benefit of being both very active for NOx but very stable
thermally and chemically otherwise.
[0031] While this invention has been described as having a
preferred design, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *