Apparatus and method for conditioning a fluid

Abstract

A fuel conditioning apparatus for de-oxygenating a liquid hydrocarbon fuel has a catalyst portion which, in turn, has an inlet portion and an outlet portion. A hydrocarbon fuel stream is fed through the inlet portion and into the catalyst portion where it passes over a catalytically active component. The catalytically active component promotes the reaction of the fuel with the dissolved oxygen in the fuel stream, converting it into less chemically reactive forms and thereby reducing the fuel's propensity to form carbonaceous deposits.

Claims

1. An apparatus for conditioning a liquid hydrocarbon fuel, the liquid hydrocarbon fuel comprising a quantity of dissolved oxygen, the apparatus comprising: a housing, having: an inlet portion; an outlet portion; and a catalyst portion in fluid communication with the inlet and outlet portions, the catalyst portion having a catalyst surface coated only with one or more metal oxides selected from the group consisting of vanadium oxide, iron oxide, cobalt oxide, aluminium oxide, magnesium oxide, zinc oxide, cerium oxide, lanthanum oxide, ruthenium oxide, palladium oxide, and platinum oxide; and a pump configured to provide a volumetric flow of the liquid hydrocarbon fuel through the housing at a space velocity of approximately 300 hr.sup.1, wherein the catalytic surface is configured to promote a reaction of at least some of the dissolved oxygen with the liquid hydrocarbon fuel, whereby peroxy and hydroperoxide intermediate products of the reaction are converted to more stable oxygenated products, to thereby reduce the quantity of dissolved oxygen.

2. The apparatus as claimed in claim 1, wherein the housing further comprises a heater configured to increase the temperature of the liquid hydrocarbon fuel entering the catalyst portion to a temperature greater than 40 C.

3. The apparatus as claimed in claim 1, wherein the housing further comprises a heater configured to increase the temperature of the liquid hydrocarbon fuel entering the catalyst portion to a temperature greater than 100 C.

4. The apparatus as claimed in claim 1, wherein the catalyst portion further comprises a slurry bed reactor.

5. The apparatus as claimed in claim 1, wherein the catalyst portion further comprises a fixed bed reactor.

6. The apparatus as claimed in claim 5, wherein the fixed bed reactor comprises a porous monolithic structure through which the volumetric flow of fuel passes, the monolithic structure being selected from the group consisting of: metal monoliths, refractory oxide monoliths, metallic foams and ceramic foams.

7. The apparatus as claimed in claim 6, wherein the one or more metal oxides are deposited onto the surface of the porous monolithic structure.

8. The apparatus as claimed in claim 1, wherein the catalytic surface comprises a surface area determined to react at least some of the oxygen dissolved in the liquid hydrocarbon fuel, with the fuel itself, at a rate commensurate with the space velocity of the fuel.

9. A method for conditioning a liquid hydrocarbon fuel, the fuel comprising a quantity of dissolved oxygen, the method comprising the step of: (i) flowing a volume of the fuel through the apparatus according to claim 1, thereby reducing the quantity of dissolved oxygen.

10. The method as claimed in claim 9, wherein the volumetric flow of the fuel has a space velocity of approximately 300 hr.sup.1.

11. The method as claimed in claim 9, the method comprising the additional initial step of: (i) heating the fuel to a temperature greater than 40 C.

12. The method as claimed in claim 9, the method comprising the additional initial step of: (i) heating the fuel to a temperature greater than 100 C.

13. A method of transferring thermal energy from a sub-system of an aircraft, the aircraft having at least one gas turbine engine, the gas turbine engine being supplied with a liquid hydrocarbon fuel, the fuel comprising a quantity of dissolved oxygen, the method comprising the steps of: (i) flowing a volume of the fuel through the apparatus according to claim 1, thereby reducing the quantity of dissolved oxygen; (ii) transferring thermal energy from the sub-system to the fuel that has a reduced quantity of dissolved oxygen; and (iii) combusting the fuel that has increased thermal energy in the at least one gas turbine engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) There now follows a description of an embodiment of the invention, by way of non-limiting example, with reference being made to the accompanying drawings in which:

(2) FIG. 1 shows a schematic arrangement of a fuel conditioning apparatus according to a second embodiment of the invention;

(3) FIG. 2 shows a schematic arrangement of a fuel conditioning apparatus according to a third embodiment of the invention; and

(4) FIG. 3 shows a schematic cross sectional view through a catalyst portion of the apparatus of FIGS. 1 and 2.

DETAILED DESCRIPTION

(5) Various hydrocarbon liquids are commonly used as fuels for internal combustion engines such as, for example, gas turbine engines. When exposed to air, most hydrocarbon liquids will absorb oxygen into solution in the liquid.

(6) This dissolved molecular oxygen, while not being part of the chemical composition of the hydrocarbon liquid, is a significant factor contributing to a fuel's thermal stability. The absorbed oxygen readily reacts with the fuel at elevated temperatures to generate free-radical chemical species that lead to the formation of thermal-oxidative deposits which can adversely affect the performance of the fuel system.

(7) In a first embodiment of the invention, shown schematically in FIG. 1, a volume of a hydrocarbon fuel 120 having a quantity of dissolved oxygen is passed through a catalyst system 110.

(8) The catalyst system 110 comprises a catalytically active component (not shown) which is capable of promoting the reaction of at least some of the dissolved oxygen in the fuel 120 with the fuel 120 itself. As a result, the conditioned flow of fuel 130 has a lower quantity of dissolved oxygen than the unconditioned flow of fuel 120.

(9) According to a second embodiment of the invention a fuel conditioning apparatus (see FIG. 1) is designated generally by the reference numeral 100. The fuel conditioning apparatus 100 is intended for use in, for example, an unmanned autonomous aircraft.

(10) The fuel conditioning apparatus 100 comprises a catalyst portion 110 having an inlet portion 140 and an outlet portion 150.

(11) In the first embodiment, the catalyst portion 110 comprises a metallic substrate 160 onto the surface of which has been deposited a catalytically active component (not shown). The metallic substrate 160 is formed with a spiral arrangement of interleaved flat metal sheets 162 and corrugated metal sheets 164.

(12) In this embodiment of the invention, the catalytically active component comprises iron and/or vanadium oxides deposited as a coating 180 on the surface of the metallic substrate 160.

(13) In other embodiments of the invention, the catalyst coating 180 on the surface of the metallic substrate 160 comprises at least one metal selected from Groups 8 to 10 of the IUPAC periodic table, and/or at least one metal oxide from the group comprising vanadium oxide, iron oxide, cobalt oxide, aluminium oxide, magnesium oxide, zinc oxide, cerium oxide, lanthanum oxide, ruthenium oxide, palladium oxide, and platinum oxide.

(14) In another embodiment of the invention, the catalyst portion 110 comprises catalyst pellets with the catalytically active component comprising at least one metal selected from Groups 8 to 10 of the IUPAC periodic table. The, catalytically active component may comprise at least one metal oxide from the group comprising vanadium oxide, iron oxide, cobalt oxide, aluminium oxide, magnesium oxide, zinc oxide, cerium oxide, lanthanum oxide, ruthenium oxide, palladium oxide, and platinum oxide.

(15) In use, the hydrocarbon fuel which is to be conditioned is fed as a fuel stream 120 through the inlet portion 140 and into the catalyst portion 110.

(16) The fuel stream 120 may be fed into the catalyst portion 110 by any suitable means, such as, for example, an electric pump (not shown).

(17) The fuel stream 120 then passes over the catalyst which promotes the reaction of dissolved oxygen with the fuel to form less chemically reactive species and thereby reduces the fuel's propensity to form carbonaceous deposits.

(18) The flow rate of the fuel flowing into the catalyst portion 110 may be selected such that the duration for which the fuel is in contact with the catalytically active component (defined as the residence time) is sufficient for substantially all of the dissolved oxygen in the fuel to be converted to a less reactive form.

(19) In this embodiment, the space velocity of the fuel entering the catalyst portion 110 is approximately 300 hr.sup.1. In other embodiments, the space velocity may be within the range of 1 to 1000 hr.sup.1.

(20) The fuel conditioning apparatus 100 may be operated at ambient pressure, as in the present embodiment. Alternatively, the apparatus 100 may be operated at an elevated pressure.

(21) After passing over the catalytically active component, the conditioned (or de-oxygenated) fuel stream 130 exits the catalyst portion 110 through the exit portion 150.

(22) The de-oxygenated fuel stream 130 may then be used in a fuel-to-air heat exchanger to absorb thermal energy from a hot air stream generated elsewhere within the aircraft.

(23) Referring to FIG. 2, a fuel conditioning apparatus according to a third embodiment of the invention is designated generally by the reference numeral 200. Features of the apparatus 200 which correspond to those of apparatus 100 have been given corresponding reference numerals for ease of reference.

(24) The fuel conditioning apparatus 200 comprises a catalyst portion 110 having an inlet portion 140 and an outlet portion 150, and a heater 210 positioned upstream of the inlet portion 140.

(25) In use, the fuel stream 120 passes through the heater 210 which is configured to raise the temperature of the fuel stream 220 as it enters the inlet portion 140 to approximately 110 C.

(26) The catalyst portion 110 of the second embodiment operates in exactly the same manner as for the first embodiment.

(27) The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.