U.S. patent application number 11/071854 was filed with the patent office on 2006-09-07 for catalytic fuel deoxygenation system.
This patent application is currently assigned to United Technologies Corporation. Invention is credited to Foster P. Lamm, Thomas H. Vanderspurt.
Application Number | 20060196174 11/071854 |
Document ID | / |
Family ID | 36942771 |
Filed Date | 2006-09-07 |
United States Patent
Application |
20060196174 |
Kind Code |
A1 |
Lamm; Foster P. ; et
al. |
September 7, 2006 |
Catalytic fuel deoxygenation system
Abstract
A fuel system for an energy conversion device includes a
deoxygenator system with a reducing system and an active metal
catalyst system downstream thereof. The reducing system injects a
reducing agent such as hydrogen into the liquid hydrocarbon fuel
which contains the dissolved oxygen. The liquid hydrocarbon fuel
with the dissolved oxygen is thereby enriched with the reducing
agent prior to communication to the active catalyst system which
reactively consumes the free oxygen dissolved within the liquid
hydrocarbon fuel.
Inventors: |
Lamm; Foster P.; (South
Windsor, CT) ; Vanderspurt; Thomas H.; (Glastonbury,
CT) |
Correspondence
Address: |
CARLSON, GASKEY & OLDS, P.C.
400 WEST MAPLE ROAD
SUITE 350
BIRMINGHAM
MI
48009
US
|
Assignee: |
United Technologies
Corporation
|
Family ID: |
36942771 |
Appl. No.: |
11/071854 |
Filed: |
March 3, 2005 |
Current U.S.
Class: |
60/288 |
Current CPC
Class: |
Y02E 20/34 20130101;
F23K 2900/05081 20130101; F23K 5/08 20130101; Y02E 20/344
20130101 |
Class at
Publication: |
060/288 |
International
Class: |
F01N 3/00 20060101
F01N003/00 |
Claims
1. A fuel system comprising: a fuel circuit for communicating a
liquid hydrocarbon fuel; a reducing system in communication with
said fuel circuit for injecting a reducing agent into the liquid
hydrocarbon fuel; and an active catalyst system downstream of said
reducing system in communication with said fuel circuit to at least
partially deoxygenate the liquid hydrocarbon fuel.
2. The fuel system as recited in claim 1, wherein said reducing
agent includes hydrogen.
3. The fuel system as recited in claim 1, wherein said active
catalyst system includes a metallic compound.
4. The fuel system as recited in claim 1, wherein said active
catalyst system includes a metal including at least one of the
following materials: copper, chromium, platinum, rhodium, iridium,
ruthenium, palladium, silver, nickel, cobalt or rhenium.
5. The fuel system as recited in claim 1, wherein said active
catalyst system generates water and thermal energy from the liquid
hydrocarbon fuel and the reducing agent.
6. A method of minimizing dissolved oxygen from within a fuel
system comprising the steps of: (1) injecting a reducing agent into
a liquid hydrocarbon fuel containing a dissolved oxygen; and (2)
communicating the reducing agent and the liquid hydrocarbon fuel
through an active metal catalyst system to minimize the dissolved
oxygen within the liquid hydrocarbon fuel.
7. A method as recited in claim 5, wherein said step (1) further
comprises the steps of: injecting hydrogen into the liquid
hydrocarbon fuel.
8. A method as recited in claim 5, wherein said step (2) further
comprises the steps of: generating water and thermal energy from
the liquid hydrocarbon fuel and the reducing agent.
9. A method of minimizing dissolved oxygen from within a fuel
system comprising the steps of: (1) communicating a liquid
hydrocarbon fuel containing a dissolved oxygen from a fuel tank;
(2) injecting a reducing agent into the liquid hydrocarbon fuel;
(3) communicating the reducing agent and the liquid hydrocarbon
fuel through an active catalyst system to minimize the dissolved
oxygen within the liquid hydrocarbon fuel; and (4) communicating
the liquid hydrocarbon fuel from said step (3) to a gas turbine
engine.
10. A method as recited in claim 8, wherein said step (2) further
comprises the steps of: injecting hydrogen into the liquid
hydrocarbon fuel.
11. A method as recited in claim 8, wherein said step (3) further
comprises the steps of: generating water and thermal energy from
the liquid hydrocarbon fuel and the reducing agent.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to stabilizing fuel by
deoxygenation, and more particularly to catalytic
deoxygenation.
[0002] Fuel is often utilized in aircraft as a coolant for various
aircraft systems. The presence of dissolved oxygen in hydrocarbon
jet fuels may be objectionable because the oxygen supports
oxidation reactions that yield undesirable by-products. Dissolution
of air in jet fuel results in an approximately 70 ppm oxygen
concentration. When aerated fuel is heated between 350.degree. F.
and 850.degree. F. the oxygen initiates free radical reactions of
the fuel resulting in deposits commonly referred to as "coke" or
"coking." Coke may be detrimental to the fuel lines and may inhibit
combustion. The formation of such deposits may impair the normal
functioning of a fuel system, either with respect to an intended
heat exchange function or the efficient injection of fuel.
[0003] Various conventional fuel deoxygenation techniques are
currently utilized to deoxygenate fuel. Typically, lowering the
oxygen concentration to 2 ppm is sufficient to overcome the coking
problem.
[0004] One conventional Fuel Stabilization Unit (FSU) utilized in
aircraft removes oxygen from jet fuel by producing an oxygen
pressure gradient across a membrane permeable to oxygen. The FSU
includes a plurality of fuel plates sandwiched between oxygen
permeable membranes and porous substrate plates disposed within a
housing to extract oxygen from the fuel by a pressure differential
across the membrane. Although effective, the fuel plate FSU may be
relatively difficult and expensive to manufacture.
[0005] Accordingly, it is desirable to provide for the effective
deoxygenation of hydrocarbon fuel in an uncomplicated and robust
system.
SUMMARY OF THE INVENTION
[0006] The fuel system for an energy conversion device according to
the present invention includes a deoxygenator system which includes
a reducing system and an active catalyst system downstream thereof.
The reducing system injects a reducing agent such as hydrogen into
the liquid hydrocarbon fuel which contains the dissolved oxygen.
The liquid hydrocarbon fuel with the dissolved oxygen is thereby
enriched with the reducing agent prior to communication to the
active catalyst system which reactively consumes the free oxygen
dissolved within the liquid hydrocarbon fuel.
[0007] The present invention therefore provides for the effective
deoxygenation of hydrocarbon fuel in an uncomplicated and robust
system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The various features and advantages of this invention will
become apparent to those skilled in the art from the following
detailed description of the currently preferred embodiment. The
drawings that accompany the detailed description can be briefly
described as follows:
[0009] FIG. 1 is a general schematic block diagram of an energy
conversion device (ECD) and an associated fuel system employing a
fuel deoxygenator in accordance with the present invention; and
[0010] FIG. 2 is a flow chart illustrating operation of the fuel
deoxygenator system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] FIG. 1 illustrates a general schematic view of a fuel system
10 for an energy conversion device (ECD) 12. A deoxygenator system
14 receives liquid fuel F from a reservoir 16 such as a fuel tank.
The fuel F is typically a liquid hydrocarbon fuel such as jet fuel.
The ECD 12 may exist in a variety of forms in which the fuel, at
some point prior to eventual use for processing, for combustion or
for some form of energy release, acquires sufficient heat to
support autoxidation reactions and coking if dissolved oxygen is
present to any significant extent in the fuel.
[0012] One form of the ECD 12 is a gas turbine engine, and
particularly such engines in high performance aircraft, however,
other ground vehicles and power stations will likewise benefit from
the present invention. Typically, the fuel also serves as a coolant
for one or more sub-systems in the aircraft and becomes heated as
it is delivered prior to combustion.
[0013] A heat exchange system 18 represents a system through which
the fuel passes in a heat exchange relationship. It should be
understood that the heat exchange system 18 may be directly
associated with the ECD 12 and/or distributed elsewhere in the fuel
system 10. The heat exchange system 18 may alternatively or
additionally include a multiple of heat exchanges distributed
throughout the system.
[0014] As generally understood, fuel F stored in the reservoir 16
normally contains dissolved oxygen, possibly at a saturation level
of approximately 70 ppm. A fuel pump 20 draws the fuel F from the
reservoir 16 into the fuel circuit 17. The fuel pump 20
communicates with the reservoir 16 via a fuel reservoir conduit 22
and a valve 24 to a fuel inlet 26 of the deoxygenator system 14.
The pressure applied by the fuel pump 20 assists in circulating the
fuel F through the deoxygenator system 14 and other portions of the
fuel system 10. As the fuel F passes through the deoxygenator
system 14, oxygen is selectively removed.
[0015] The deoxygenated fuel Fd flows from a fuel outlet 30 of the
deoxygenation system 14 via a deoxygenated fuel conduit 32, to the
heat exchange system 18 and to the ECD 12 such as the combustor of
a gas turbine engine. A portion of the deoxygenated fuel may be
recirculated, as represented by recirculation circuit 33 to either
the deoxygenation system 14 and/or the reservoir 16. It should be
understood that although a particular component arrangement is
disclosed in the illustrated embodiment, other arrangements will
benefit from the instant invention.
[0016] The deoxygenator system 14 includes a reducing system 34 and
an active catalyst system 36 downstream thereof. The reducing
system 34 injects a reducing agent such as hydrogen into the liquid
hydrocarbon fuel which contains the dissolved oxygen. The liquid
hydrocarbon fuel with the dissolved oxygen is thereby enriched with
the reducing agent prior to communication to the active 1 catalyst
system 36. The active catalyst system 36 includes a catalyst such
as a platinum or other active catalyst to reactively consume the
free oxygen dissolved within the liquid hydrocarbon fuel. The
catalytic material may alternatively or additionally be a metal
such as but not limited to copper, chromium, platinum, rhodium,
iridium, ruthenium, palladium, rhenium and any combination of these
materials or a metal multimetallic compound or compounds including
transition metal or multimetallic complexes or supported complexes.
One such preferred catalyst is a platinum/palladium catalyst on a
mildly acidic support optimized with regard to pore structure,
surface area, metal dispersion, etc. A worker having the benefit of
this disclosure would understand the specific composition of
catalyst required to reduce, in the chemical sense, the dissolved
oxygen in the fuel.
[0017] The catalytic material may be supported on a honeycomb
structure disposed within the metal catalyst system 36.
Alternatively, the catalytic material may be supported on granules,
extrudates, monoliths, or other known catalyst support structures.
The active catalyst system 36 may be disposed adjacent heat
producing components of the system 10. Preferably, the metal
catalyst system is disposed in relatively close proximity with the
ECD 12 and most preferably within a housing of the ECD such that
heat generated by the ECD 12 elevates the temperature of the active
catalyst system 36 to temperatures required to initiate catalytic
reactions. The active catalyst system 36 may alternatively be
utilized to absorb thermal energy from other systems and/or in
conjunction with the heat exchange system 18. The absorbed thermal
energy will elevate the temperature of the active catalyst system
36 to temperatures providing optimum operation. Further, it is
within the contemplation of this invention to heat the active
catalyst system 36 by external systems.
[0018] In operation, as the liquid hydrocarbon fuel and the
reducing agent from the reducing system 34 are passed through the
active metal catalyst system 36, water and thermal energy are
produced as byproducts during the deoxygenation process (FIG. 2). A
water collection system 38 communicates with the deoxygenator
system 14 to receive water therefrom. It should be understood that
the water may be collected and/or expelled from the fuel system 10
and the thermal energy may be further utilized within a thermal
management subsystem.
[0019] Although particular step sequences are shown, described, and
claimed, it should be understood that steps may be performed in any
order, separated or combined unless otherwise indicated and will
still benefit from the present invention.
[0020] The foregoing description is exemplary rather than defined
by the limitations within. Many modifications and variations of the
present invention are possible in light of the above teachings. The
preferred embodiments of this invention have been disclosed,
however, one of ordinary skill in the art would recognize that
certain modifications would come within the scope of this
invention. It is, therefore, to be understood that within the scope
of the appended claims, the invention may be practiced otherwise
than as specifically described. For that reason the following
claims should be studied to determine the true scope and content of
this invention.
* * * * *