U.S. patent application number 11/046298 was filed with the patent office on 2005-06-23 for fast light-off catalytic reformer.
This patent application is currently assigned to Delphi Technologies, Inc.. Invention is credited to Fisher, Galen Bruce, Kirwan, John E..
Application Number | 20050132650 11/046298 |
Document ID | / |
Family ID | 24418286 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050132650 |
Kind Code |
A1 |
Fisher, Galen Bruce ; et
al. |
June 23, 2005 |
Fast light-off catalytic reformer
Abstract
A fast light-off catalytic reformer and method includes at least
one preferably substantially cylindrical reactor tube having an
inlet for receiving a flow of fuel and a flow of air, a reforming
catalyst disposed within the reactor tube for converting the fuel
and air to a reformate stream, and an outlet for discharging the
produced reformate stream. An ignition device disposed within the
reactor tube initiates an exothermic reaction between the fuel and
air. Heat generated thereby provides fast light-off of the
reforming catalyst. An associated control system selects fuel and
air flow delivery rates and operates the ignition device to achieve
fast light-off of the reforming catalyst at start-up and to
maintain the catalyst at a temperature sufficient to optimize
reformate yield. The rapid production of high yields of reformate
is particularly suitable for use in an on-board reforming strategy
for meeting SULEV emissions with spark-ignition engines, especially
with larger, higher emitting vehicles.
Inventors: |
Fisher, Galen Bruce;
(Bloomfield Hills, MI) ; Kirwan, John E.; (Troy,
MI) |
Correspondence
Address: |
PAUL L. MARSHALL
DELPHI TECHNOLOGIES, INC.
Legal Staff, Mail Code: 480-410-202
P.O. Box 5052
Troy
MI
48007-5052
US
|
Assignee: |
Delphi Technologies, Inc.
|
Family ID: |
24418286 |
Appl. No.: |
11/046298 |
Filed: |
January 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11046298 |
Jan 28, 2005 |
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09604129 |
Jun 27, 2000 |
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6887436 |
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Current U.S.
Class: |
48/197R ;
422/105; 48/127.9; 48/198.1 |
Current CPC
Class: |
B01J 2208/00548
20130101; C01B 3/38 20130101; B01J 8/0221 20130101; B01J 2219/00213
20130101; B01J 2208/00716 20130101; B01J 2219/002 20130101; Y02P
20/52 20151101; B01J 2219/00231 20130101 |
Class at
Publication: |
048/197.00R ;
048/127.9; 048/198.1; 422/105 |
International
Class: |
B01J 008/00 |
Claims
1. A fast light-off catalytic reformer comprising: a catalytic
reformer characterized by at least one reactor tube, said reactor
tube having an inlet in a first end for receiving a flow of fuel
and a flow of air, a reforming catalyst disposed within said
reactor tube for converting said fuel and said air to a reformate
stream, and an outlet in a second end for discharging said
reformate stream; an ignition device disposed within said reactor
tube for initiating an exothermic reaction between said fuel and
said air and using heat generated thereby to provide fast light-off
of said reforming catalyst; and; a control system for selecting
fuel and air flow rate and operating said ignition device so as to
achieve fast light-off of said reforming catalyst at start-up and
to maintain said catalyst at a temperature sufficient to optimize
reformate yield.
2. The reformer of claim 1, wherein said ignition device disposed
within said reactor tube is located upstream of said reforming
catalyst, within said reforming catalyst at the front face of said
reforming catalyst, or within said reforming catalyst at the rear
face of said reforming catalyst.
3. The reformer of claim 1, wherein said ignition device comprises
a catalytic substrate or a non-catalytic substrate for receiving
electric current from a voltage source, a spark plug, a glow plug,
or a combination thereof.
4. A power generation system employing a fast light-off reformer
comprising: a catalytic reformer characterized by at least one
reactor tube, said reactor tube having an inlet in a first end for
receiving a flow of fuel and a flow of air, a reforming catalyst
disposed within said reactor tube for converting said fuel and said
air to a reformate stream, and an outlet in a second end for
discharging said reformate stream; an ignition device disposed
within said reactor tube for initiating an exothermic reaction
between said fuel and said air and using heat energy generated
thereby to provide fast light-off of said reforming catalyst; a
control system for selecting fuel and air flow rate and operating
said ignition device so as to achieve fast light-off of said
reforming catalyst at start-up and to maintain said catalyst at a
temperature sufficient to optimize reformate yield; and a power
generation system operating at least partially on reformate
fueling, said power generation system having a fuel inlet in fluid
communication with said reformer outlet.
5. The fast light-off reformer-power generation system of claim 4,
wherein said power generation system is an engine, a spark ignition
engine, a hybrid vehicle, a diesel engine, a fuel cell, a solid
oxide fuel cell, or a combination thereof.
6. A fast light-off reforming method comprising: supplying a flow
of fuel and a flow of air to a catalytic reformer, said catalytic
reformer characterized by at least one reactor tube having an inlet
for receiving said flow of fuel and air, a reforming catalyst
disposed within said reactor tube for converting said flow of fuel
and air to a reformate stream, and an outlet for discharging said
reformate stream; igniting said fuel and air within said reactor
tube to rapidly heat said reforming catalyst with heat energy
generated thereby; and controlling said fuel and air supply and
said igniting so as to achieve fast light-off of said reforming
catalyst at start-up and to maintain said reforming catalyst at a
temperature sufficient to optimize reformate yield.
7. The method of claim 6, wherein said igniting is with an ignition
device selected from the group consisting of a catalytic or
non-catalytic substrate for receiving an electric current, a spark
plug, a glow plug, or a combination thereof.
8. The method of claim 7, wherein said substrate is wire or
gauze.
9. The method of claim 6, further comprising: fueling a power
generation system at least partially with said reformate
stream.
10. The method of claim 9, wherein said power generation system is
an engine, a spark ignition engine, a hybrid vehicle, a diesel
engine, a fuel cell, a solid oxide fuel cell, or a combination
thereof.
Description
TECHNICAL FIELD
[0001] The present invention relates to a catalytic reformer and
method for converting a hydrocarbon stream to a reformate fuel
stream comprising hydrogen, and more particularly relates to a fast
light-off catalytic reformer and method for rapid production of
reformate fuel. The present invention is particularly suitable for
on-board production of reformate for hydrogen cold-start in an
internal combustion engine. The present invention is also suitable
for providing reformate to a fuel cell such as a solid oxide fuel
cell.
BACKGROUND OF THE INVENTION
[0002] A catalytic hydrocarbon fuel reformer converts a fuel stream
comprising, for example, natural gas, light distillates, methanol,
propane, naphtha, kerosene, gasoline, diesel fuel, or combinations
thereof, and air, into a hydrogen-rich reformate fuel stream
comprising a gaseous blend of hydrogen, carbon monoxide and
nitrogen (ignoring trace components). In the reforming process, the
raw hydrocarbon fuel stream is typically percolated through a
catalyst bed or beds contained within reactor tubes mounted in the
reformer vessel. The catalytic conversion process is typically
carried out at elevated catalyst temperatures in the range of about
1200.degree. F. to about 1600.degree. F.
[0003] In most reformers of this type, hot burner gas generated at
a burner generally disposed within the reformer vessel accumulates
in a primary (typically, upper) plenum within the vessel,
contacting and heating the outer surface of the reactor tubes,
thereby heating the catalyst. The hot burner gas may be directed
through a cylindrical sleeve surrounding the lower portion of each
reactor tube, so that the hot burner gas travels in close contact
with outer surfaces of the reactor tubes and effective heat
transfer occurs. Hot burner gas from the primary plenum flows
through a narrow annular passage between the internal wall of the
sleeve and the external wall of each reactor tube, and into a
secondary (lower) plenum, from which it is discharged. Seal plates
or insulation may be employed to prevent bypass of the hot burner
gases around the sleeve.
[0004] The produced hydrogen-rich reformate stream may be used, for
example, as the fuel gas stream feeding the anode of an
electrochemical fuel cell after passing the reformate stream
through a water gas shift reactor and other purification means such
as a carbon monoxide selective oxidizer. Reformate is particularly
well suited to start up a solid oxide fuel cell (SOFC) system
because the purification step for removal of carbon monoxide is not
required for an SOFC.
[0005] The hydrogen-rich reformate stream may also be used as a
hydrogen fuel to fuel an engine. Hydrogen-fueled vehicles are of
interest as low-emissions vehicles because hydrogen as a fuel or a
fuel additive can significantly reduce air pollution and can be
produced from a variety of fuels. Hydrogen provides the capability
to run an engine with very lean fuel-air mixtures that greatly
reduce production of NOx. Small amounts of supplemental hydrogen
fuel may allow conventional gasoline internal combustion engines to
reach nearly zero emissions levels. Commonly assigned, co-pending
U.S. patent application Ser. No. ______ (Attorney Docket No.
DP-301698) of Kirwan et al., entitled "System And Controls For Near
Zero Cold Start Tailpipe Emissions In Internal Combustion Engines,"
hereby incorporated by reference herein in its entirety, discloses
an on-board fuel reformer-engine system employing substantially
100% reformate fueling at start-up for near-zero cold start
hydrocarbon and NOx engine emissions. The system and method
provides for controlling the supply of one or a combination of
reformate, liquid fuel, and air to the engine and exhaust catalyst
to achieve low hydrocarbon and NOx emissions over a full range of
engine operating conditions.
[0006] While hydrogen fuel may be stored on-board to provide an
instant source of reformate fuel, on-board storage of reformate
significantly increases system size, cost and complexity. For
example, on-board storage may require high-pressure vessels,
cryogenic containers if the hydrogen is to be stored as a
compressed gas or liquid, or large volumes and weights if the
hydrogen is to be stored as a hydride. In addition, storage of
carbon monoxide may be a safety concern. Further, the refill time
for hydrogen is substantially longer than that for gasoline when
hydrogen is to be stored on-board.
[0007] What is needed in the art is a reformate-generating device
comprising a rapid start up (or "fast light-off") system. What is
further needed in the art is a rapid start-up catalytic reformer
for producing reformate suitable for feeding a power generation
system such as a fuel cell or engine.
SUMMARY OF THE INVENTION
[0008] A fast light-off catalytic reformer and method is provided.
The reformer includes at least one reactor tube having an inlet for
receiving a flow of fuel and a flow of air, a reforming catalyst
disposed within the reactor tube for converting the fuel and air to
a reformate stream, and an outlet for discharging the produced
reformate stream. An ignition device is disposed within the reactor
tube for initiating an exothermic reaction between the fuel and air
and using the heat generated thereby to provide fast light-off of
the reforming catalyst. The ignition device may be located at
various positions within the reactor tube, as desired, such as, but
not limited to, upstream of the reforming catalyst. An associated
control system selects fuel and air flow delivery rates and
operates the ignition device so as to achieve fast light-off of the
reforming catalyst at start-up and to maintain the catalyst at a
temperature sufficient to optimize reformate yield.
[0009] The method includes supplying a flow of premixed fuel and
air to the catalytic reformer and igniting the fuel and air within
the reactor tube to rapidly heat the reforming catalyst with the
heat of combustion. The method also includes controlling the fuel
and air delivery rate and the igniting so as to achieve fast
light-off at start-up and to maintain the reforming catalyst at a
temperature sufficient to optimize reformate yield.
[0010] The present fast light-off reformer and method
advantageously provides a compact and efficient system. The present
invention provides the further advantage of reducing the size of a
discrete burner and associated system for flowing and exhausting
hot burner gases in order to achieve and maintain an effective
catalyst temperature.
[0011] The present fast light-off reformer and method provides the
advantage of rapid production of high yields of reformate and is
particularly useful for an on-board reforming strategy for meeting
SULEV emissions with spark-ignition engines, especially with
larger, higher emitting vehicles. The present fast light-off
reformer and method is also well suited for providing rapid
production of reformate to other power generation systems, such as
fuel cells, and is particularly useful for start up and fueling
solid oxide fuel cells.
[0012] These and other features and advantages of the invention
will be more fully understood from the following description of
certain specific embodiments of the invention taken together with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Referring now to the drawing, which is meant to be
exemplary, not limiting:
[0014] FIG. 1 is a perspective view, partially in section, of an
embodiment of a fast light-off catalytic reformer in accordance
with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Turning to FIG. 1, a fast light-off catalytic reformer in
accordance with one possible embodiment of the present invention
includes a reactor tube 10 having an inlet 12 in a first end for
receiving a flow of fuel and a flow of air, shown as combined
fuel-air stream 14. Reactor tube 10 may be any shape, but typically
comprises a substantially cylindrical reactor tube. While the
present description discusses a single reactor tube 10, reforming
catalyst 16, and ignition device 22, the present fast light-off
reformer may comprise one or more reactor tubes, as desired.
[0016] Reforming catalyst 16 is disposed within the reactor tube
10. Reforming catalyst 16 may comprise any reforming catalyst
suitable for converting the fuel feedstock and air to reformate,
including, but not limited to, for example, rhodium, platinum,
their alloys, and combinations thereof. Preferably, a protective
coating or firewall (not shown) is disposed about catalyst 16.
During operation, air and fuel 14 flows through inlet 12 and is
converted in catalyst 16 to a hydrogen rich reformate fuel stream
18 that is discharged through outlet 20.
[0017] Ignition device 22 is disposed within the reactor tube 10 to
initiate an exothermic reaction in fuel and air flow 14. Heat
generated by this reaction is used to provide fast light-off (i.e.,
extremely rapid heating) of the reforming catalyst 16. The ignition
device may be located upstream of the catalyst, within the catalyst
at the front face thereof, or within the catalyst at the rear face
of the catalyst. In a preferred embodiment, the ignition device 22
is disposed within the reactor tube 10 upstream of the reforming
catalyst 16, i.e., between inlet 12 and reforming catalyst 16.
Ignition device 22 may be any device suitable for initiating
exothermic reactions between fuel and air 14, including, but not
limited to, a catalytic or non-catalytic substrate, such as a wire
or gauze, for receiving electric current from a voltage source, a
spark plug, a glow plug, or a combination thereof.
[0018] An associated control system (30) selects and maintains the
appropriate fuel and air delivery rates and operates the ignition
device 22 so as to achieve fast light-off of the reforming catalyst
16 at start-up and to maintain catalyst 16 at a temperature
sufficient to optimize reformate 18 yield. The control means used
herein may comprise any of various control means known in the art
for providing air and fuel control and metering functions.
[0019] Excellent reformate yields from the reactor depend upon both
a sufficiently high catalyst temperature and the appropriate
air-fuel ratio. The optimum air-fuel mixture for producing
reformate is very fuel rich, but leaner mixtures provide higher
temperatures for rapidly heating the catalyst. The control system
varies air-fuel ratio during start-up of the reformer to rapidly
obtain both the temperatures and air-fuel mixtures required for
high reformate yields.
[0020] The present fast light-off catalytic reformer and method
produce rapid, high yields of reformate fuel. The produced
reformate may be bottled in a vessel (40) or used to fuel any
number of systems operating partially or wholly on reformate fuel.
Such power generation systems (50) may include, but are not limited
to, engines such as spark ignition engines, hybrid vehicles, diesel
engines, fuel cells, particularly solid oxide fuel cells, or
combinations thereof. The present fast light-off reformer and
method may be variously integrated with such systems, as desired.
For example, the present fast light-off reformer may be employed as
an on-board reformer for a vehicle engine operating wholly or
partially on reformate, the engine having a fuel inlet in fluid
communication with the reformer outlet 20 for receiving reformate
18 therefrom. The present fast light-off reformer and method is
particularly suitable for use as an on-board reformer for
generating a fast supply of reformate 18 for initial start-up of a
system. The present reformer and method is particularly
advantageous for hydrogen cold-start of an internal combustion
engine, providing a fast supply of hydrogen-rich reformate which
allows the engine exhaust to meet SULEV emissions levels
immediately from cold-start.
[0021] While the invention has been described by reference to
certain preferred embodiments, it should be understood that
numerous changes could be made within the spirit and scope of the
inventive concepts described. Accordingly, it is intended that the
invention not be limited to the disclosed embodiments, but that it
have the full scope permitted by the language of the following
claims.
* * * * *