Internal recycle reactor for catalytic inerting

An internal recycle reactor for catalytic inerting has a monolithic body having a motive fluid duct, a suction chamber, a mixing region, a reactor section, an outlet, and a recycle passage. The suction chamber includes a suction chamber inlet. The mixing region is configured to receive gaseous fluids from the motive fluid duct and the suction chamber inlet to produce a gaseous mixture. The reactor section includes a catalyst and is configured to receive the gaseous mixture from the mixing region. The outlet is configured to deliver an exhaust gas from the reactor section and the recycle passage is configured to deliver a portion of the exhaust gas to the suction chamber inlet.

BACKGROUND

The present disclosure relates generally to air inerting systems for aircraft and other applications where an inert gas may be required and, more specifically, to catalytic oxidation of fuel.

Aircraft fuel tanks can contain potentially combustible combinations of oxygen, fuel vapors, and ignition sources. Commercial aviation regulations require actively managing the risk of explosion in the vapor space (i.e., ullage) above the liquid fuel in fuel tanks. This can be accomplished by reducing the oxygen concentration in the ullage by displacing the air in the ullage with an inert gas containing less than 12% oxygen. Conventional fuel tank inerting (FTI) methods include air separation module (ASM) methods that utilize hollow fiber membranes to separate ambient air into nitrogen-enriched air, which is directed to fuel tanks, and oxygen-enriched air, which is usually rejected overboard. AMS methods rely on bleed air from a compressor stage of an engine, which is not always available in the desired quantity at sufficient pressure thereby requiring aircraft engines to idle during descent.

SUMMARY

In one aspect, an internal recycle reactor for catalytic inerting has a monolithic body having a motive fluid duct, a suction chamber, a mixing region, a reactor section, an outlet, and a recycle passage. The suction chamber includes a suction chamber inlet. The mixing region is configured to receive gaseous fluids from the motive fluid duct and the suction chamber inlet to produce a gaseous mixture. The reactor section includes a catalyst and is configured to receive the gaseous mixture from the mixing region. The outlet is configured to deliver an exhaust gas from the reactor section and the recycle passage is configured to deliver a portion of the exhaust gas to the suction chamber inlet.

In another aspect, an internal recycle reactor for catalytic inerting includes an ejector and a recycle passage. The ejector includes a motive fluid duct, a suction chamber having a suction chamber inlet, a mixing region, a reactor section, and an outlet. The mixing region is configured to receive gaseous fluids from the motive fluid duct and the suction chamber inlet and to produce a gaseous mixture. The reactor section is positioned to receive the gaseous mixture from the mixing region and configured to react with the gaseous mixture and the outlet is configured to deliver an exhaust gas from the reactor section. The recycle passage extends from the outlet to the suction chamber inlet and is configured to deliver a portion of the exhaust gas to the suction chamber inlet.

In yet another aspect, a method of catalytic inerting includes flowing a reactant gas to a first inlet of an ejector, flowing a portion of an exhaust gas from an ejector outlet to a second inlet of the ejector, mixing the reactant gas with the exhaust gas to produce a gaseous mixture, flowing the gaseous mixture through a catalyst disposed in the ejector, and flowing the exhaust gas from the catalyst to an outlet.

While the above-identified figures set forth embodiments of the present invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features, steps and/or components not specifically shown in the drawings.

DETAILED DESCRIPTION

Catalytic oxidation of fuel is an alternative to traditional air separation modules (ASM) used to produce inert air onboard an aircraft for uses such as fuel tank inerting (FTI) and fire suppression. Catalytic oxidation of fuel can leverage a variety of incoming air sources, not limited to bleed air, to produce inert air with oxygen levels below the required 12% oxygen (or 9% for military engines) over a range of conditions. In catalytic oxidation, a catalyst can be used to catalyze a chemical reaction between oxygen (O2) and fuel to produce carbon dioxide (CO2) and water. Catalytic oxidation is an exothermic reaction, which can produce a significant amount of heat. The heat produced must be managed to prevent damage to the oxidizer system and to minimize any hazard to the aircraft. One method to manage the heat within the oxidizer system is to recycle a portion of the oxidizer exhaust back to the inlet of the reactor. The exhaust gas can internally cool the reactor and minimize heat release within the reactor by reducing the amount of oxygen and fuel available for reaction, minimizing the difference between inlet and outlet reactant concentrations, and changing the residence time across the catalyst. One recycle or backmix reactor design uses an external device, such as a blower or ejector (jet pump) to move exhaust from the outlet of the reactor back to the inlet of the reactor. Another design uses an impeller within the reactor to cause internal recirculation. The present disclosure provides an alternative approach in which a catalyst and recycle loop are integrated to form a single body ejector-style reactor, which eliminates the need for an external recycle device.

FIG. 1is a simplified schematic diagram of inert gas generating system10, which can be present on-board an aircraft. Inert gas generating system10includes fuel tank12, which includes ullage space14above liquid hydrocarbon fuel16and at least one vent17, combustion air source18providing combustion air19(shown inFIG. 2), catalytic oxidation unit (COU)20with internal recycle (shown in greater detail inFIGS. 2 and 3), and controller24. Inert gas generating system10can produce a predominantly inert gas by mixing hydrocarbon fuel16and combustion air19, in the presence of a catalyst (i.e., COU20). Reaction of hydrocarbon fuel16and combustion air19produces carbon dioxide and water vapor. The water vapor can be condensed from the exhaust gas exiting COU20, for example, by heat exchanger26. The carbon dioxide is an inert gas that is mixed with nitrogen naturally found in fresh/ambient air, and which flows through COU20unreacted. The inert gas mixture of carbon dioxide and nitrogen can be directed back to fuel tank12via inert gas line27to displace gas in ullage14and/or can be directed to fire suppression systems (not shown). Controller24can be operatively coupled (e.g., electrically and/or communicatively) to components shown inFIG. 1as well as components not depicted (e.g., valves, sensors, etc.) to control operation of inert gas generating system10.

Liquid fuel16can be kerosene-based jet fuel, such as Jet-A, Jet-A1, or Jet-B fuel. For military applications, liquid fuel16can also be a jet propulsion “JP” class fuel, such as JP-5 or JP-8. Other types of fuel such as diesel, gasoline, and mixtures of fuels are also contemplated herein. Ullage space14, which is a vapor space present above liquid fuel16in fuel tank12, can contain potentially combustible fuel vapors. System10operates to reduce the risk of combustion and explosion within ullage space14by providing inert gas to maintain the oxygen concentration within ullage space14at or below 12% oxygen by volume for commercial aviation, and below 9% by volume for military applications.

In order to operate inert gas generating system10, fuel16can be extracted from fuel tank12and delivered to COU20via fuel supply line28. Delivery of fuel16to COU20can be controlled by one or more valves29. Fuel vapor16can mixed with combustion air19prior to entering COU20or within a body of COU20for reaction in COU20. In some embodiments, liquid fuel16can be directly injected into a gas supply line entering COU20(e.g., combustion air supply line30) or into a body of COU20through a fuel injector capable of atomizing fuel16for mixture with combustion air19. In alternative embodiments, fuel vapors16in ullage14can be separated from a gaseous mixture in ullage14or fuel vapor16can be produced from liquid fuel16in an evaporator container (not shown). Fuel vapor16can be delivered to COU20in combination with combustion air19through a gas supply line, such as combustion air supply line30. In some embodiments, an additional mixer, such as an ejector or jet pump, can be used to produce a gaseous mixture of fuel16and combustion air19for delivery to COU20.

Combustion air19provides a source of oxygen for reaction with hydrocarbon fuel16in COU20. Combustion air19can be supplied by one or more air sources including, but not limited to, fan bleed air, ram air, cabin outflow air, and compressor bleed air. Combustion air19can be supplied to COU20through supply line30. Delivery of combustion air19can be controlled by one or more valves31. In some embodiments, combustion air19can be cooled or heated via a heat exchanger or source of heat as known in the art to obtain an optimal inlet gas temperature for reaction in COU20(not shown). In some embodiments, a temperature of the gaseous mixture of fuel16and combustion air19at a COU20inlet is between 150° C. and 225° C., but this temperature can vary depending on the type of catalyst used.

COU20contains a catalyst capable of inducing a chemical reaction between fuel16and combustion air19. The catalyst material can include, but is not limited to, a noble metal, transition metal, metal oxide, and combinations thereof. The catalyst in COU20induces a chemical reaction between fuel16and combustion air19, which produces an exhaust gas containing carbon dioxide, water, and any unreacted gases, which can be delivered from COU20through line32. The reaction is exothermic and, therefore, can also generate a significant amount of heat depending on the amount of reactants available for reaction. The chemical reaction for a stoichiometric mixture of fuel16and combustion air19has a general formula of:
CxHy+(x+y/4)O2+N2→xCO2+(y/2)H2O+N2

The exact reactions depend on the type of fuel used and types of hydrocarbons present in the fuel mixture. For a stoichiometric mixture, the reaction results in complete consumption of oxygen and hydrocarbons to produce an inert gas containing carbon dioxide, water, and nitrogen, which exits COU20through outlet34. Any inert gas species (e.g., carbon dioxide, water, and nitrogen) that enter COU20in the gaseous mixture of hydrocarbon fuel16and combustion air19will not react and will thus pass through COU20chemically-unchanged. If an oxygen-to-fuel ratio (ratio of oxygen in combustion air19to fuel16) is greater than stoichiometry, or having a stoichiometric ratio greater than 1, more oxygen than needed for reaction of hydrocarbons will enter COU20. Any unreacted oxygen will exit COU20in the exhaust gas. Ideally, the gas returned to fuel tank12for inerting of ullage space14or directed to fire suppression systems has a minimal or near-zero concentration of oxygen for maximum inerting effect. This is accomplished by having a near-stoichiometric air-to-fuel ratio.

The reaction of fuel16and combustion air19at near-stoichiometric conditions can result in significant heat release, which can damage COU20. The amount of heat produced can be managed and reduced by recycling a portion of the exhaust gas through one or more internal recycle passages back to a catalyst inlet.

FIG. 2provides a schematic view of one embodiment of internal recycle COU20. COU20includes integrated reactor body36, motive fluid duct38, fuel inlet40, suction chamber42, mixing region44, reactor section46, outlet34, and recycle passages50. Motive fluid duct38is located upstream of reactor section46and configured to deliver a motive flow of combustion air19to reactor section46for reaction. Outlet34(also shown inFIG. 1) is an outlet to reactor section46and configured to deliver exhaust gas51from reactor section46and COU20. Recycle passages50connect outlet34with suction chamber inlets53upstream of reactor section46. The motive flow delivered through motive fluid duct38draws exhaust gas51through recycle passages50into suction chamber42upstream of reactor section46. Exhaust gas51mixes with combustion air19delivered through motive fluid duct38and fuel delivered through fuel inlet40in mixing region44. The gaseous mixture produced in mixing region44is then delivered to reactor section46for catalytic inerting.

Integrated reactor body36can include multiple components, which can be integrally formed, removably fastened, fixedly fastened, or manufactured or assembled using combinations thereof. Integrated reactor body36can be exposed to high temperatures due to the heat of reaction in reactor section46. In some embodiments, temperatures may reach or exceed 1200 degrees Celsius. For high temperature applications, integrated reactor body36can be made of alloys, such as Inconel 800H/HT, to withstand thermal stresses.

Motive fluid duct38includes nozzle52configured to direct combustion air19to reactor section46and to provide a motive flow to create suction in suction chamber42. Combustion air19is supplied by combustion air source18(shown inFIG. 1). As previously discussed, combustion air19can be a pressurized gas, including but not limited to compressor bleed air. Combustion air19can be cooled or heated via a heat exchanger or source of heat as known in the art (not shown) to obtain an optimal inlet gas temperature for reaction in COU20.

Nozzle52can have a converging shape configured to accelerate the flow of combustion air through the nozzle and increase the velocity of combustion air19. Nozzle52can have an outlet orifice54opening toward reactor section46to direct motive flow to catalyst60. The high velocity combustion air19reduces pressure in suction chamber42. A pressure differential created across recycle passage50causes higher pressure exhaust gas51at outlet34to enter recycle passage inlet56and flow toward lower pressure suction chamber42. Combustion air19enters suction chamber42at inlet53. The pressure differential created by motive fluid duct38provides for automatic recycle of exhaust gas51without the need for an external blower or pump. Delivery of the combustion air19can be controlled by controller24and one or more valves to increase or decrease the velocity of combustion air19entering COU20and thereby recycle of exhaust gas51.

Fuel16, supplied by fuel tank12(shown inFIG. 1) enters COU20via supply line28(shown inFIG. 1) and fuel inlet40. Fuel inlet40can be configured to directly inject liquid fuel16into mixing region44or a region upstream of mixing region44via a fuel injector nozzle capable of atomizing liquid fuel16. Alternatively, fuel vapor16can supplied from ullage (shown inFIG. 1) or an evaporator (not shown) via supply line28to fuel inlet40.

Mixing region44is immediately upstream of reactor section46and is configured to mix combustion air19, fuel16, and exhaust gas51to produce gaseous mixture58upstream of reactor section46. Gaseous mixture58enters reactor section46for catalytic reaction.

Reactor section46contains catalyst60. Catalyst60can be a monolithic solid body permeable to gaseous mixture58. In some embodiments, catalyst60can have a honeycomb-like structure suitable for providing a reactive surface area as known in the art. Catalyst60can consist of noble metals, transition metals, metal oxides, and combinations thereof. Both catalyst60and reactor section46can be cylindrical in shape with catalyst60closely fitted within reactor section46to prevent gaseous mixture58from bypassing catalyst60. Catalyst60has a cross-sectional area substantially equal to an inner cross-sectional area of reactor section46or an outer diameter substantially equal to an inner diameter of reactor section46. In such configuration, gaseous mixture58is forced to flow through catalyst60. As shown inFIG. 2, catalyst60extends a full length of reactor section46. In a non-limiting example, catalyst60can be supported on a metallic or ceramic monolith substrate having a length ranging from 25 mm to 150 mm, diameter of 25 mm to 90 mm, and number of cells per square inch (CPSI) between 200 and 600 (31-93 cells per square centimeter).

As previously discussed, fuel16and combustion air19react in the presence of catalyst60to produce carbon dioxide and water. The addition of exhaust gas51can internally cool the reactor and minimize heat release within the reactor by reducing the amount of oxygen and fuel available for reaction, minimizing the difference between inlet and outlet reactant concentrations across catalyst60, and changing the residence time across catalyst60. Because the inert gases present in exhaust gas51(carbon dioxide, water, and nitrogen) do not react with catalyst60, no heat is generated by this portion of exhaust gas51flowing through catalyst60. The inert gas passes through catalyst60chemically unchanged, although it can absorb heat generated in reaction section46by the reaction of fuel16and combustion air19.

Exhaust gas51can be recycled at any given or predetermined ratio or percentage. In a non-limiting example, 95% of exhaust gas51may be recycled with only 5% being directed to ullage14or fire suppression systems. Alternatively, 5% of exhaust gas may be recycled with 95% being directed to ullage14or fire suppression systems. These values are merely examples. The amount of exhaust gas51recycled can be varied depending on a number of factors, including but not limited to, a desired reactor temperature during steady-state operation. In some embodiments, recycle can be passive with a recycle rate high as possible at all time, generally greater than 20:1. In alternative embodiments, the recycle rate can be controlled by varying the input pressure on an inlet side of the ejector via one or more control valves (e.g., varying the total flow rate of combustion air19).

Exhaust gas51is recycled through recycle passages50. Although two recycle passages50are illustrated, the number of recycle passages50can be increased or decreased as appropriate with some embodiments having only one recycle passage50. Each recycle passage50includes inlet56and outlet53(suction chamber inlet53). Inlets56are positioned at outlet34of reactor section46. Inlets56can be evenly distributed about an inner wall of outlet56or arranged in any configuration suitable for delivering exhaust gas51to an inlet of catalyst60. Suction chamber inlets53can be evenly distributed about an inner wall of suction chamber42or can be arranged in any manner suitable to facilitate mixing in mixing region44. Generally, suction inlets53can be perpendicular to nozzle outlet orifice54. Recycle passages50can be made from aluminum, stainless steel, or other material suitable for delivering a pressurized and high-temperature gas. The portion of exhaust gas51not recycled through recycle passages50is delivered out of COU20through outlet34for fuel tank inerting and/or fire suppression applications.

Integrated reactor body36integrates recycle passage50and motive fluid duct38into COU20in a manner that allows a portion of exhaust gas51to be automatically recycled through reactor section46without use of an external blower. This has the additional benefit of reducing the number of parts for system10, as well as reducing the weight and volume of the overall system.

FIG. 3provides schematic views of an alternative embodiment of internal recycle COU20ofFIG. 1, illustrated as COU20′ inFIG. 3. COU20′ includes integrated reactor body37, motive fluid duct62, suction chamber42, mixing region44, reactor section46, outlet34, and recycle passages50. Motive fluid duct62is located upstream of reactor section46and configured to deliver a motive flow of reactant gas64to reactor section46for reaction. Outlet34is an outlet to reactor section46and configured to deliver exhaust gas51from reactor section46. Recycle passages50connect outlet34with suction chamber inlets53upstream of reactor section46. The motive flow delivered through motive fluid duct62draws exhaust gas34through one or more recycle passages50into suction chamber42upstream of reactor section46. Exhaust gas51mixes with reactant gas64delivered through motive fluid duct62in mixing region44. The gaseous mixture58produced in mixing region44is then delivered to reactor section46for catalytic inerting.

Integrated reactor body37is similar to integrated reactor body36ofFIG. 2with the exception of the configuration of motive fluid duct62. Integrated reactor body37can include multiple components, including an ejector with motive fuel duct62, suction chamber42, mixing region44, reactor section46, and outlet34, and recycle passages50. These components can be integrally formed, removably fastened, fixedly fastened, or manufactured or assembled using combinations thereof. Integrated reactor body37can be exposed to high temperatures due to the heat of reaction in reactor section46. In some embodiments, temperatures may reach or exceed 1200 degrees Celsius. For high temperature applications, integrated reactor body36can be made of alloys, such as Inconel 800H/HT, to withstand thermal stresses.

Motive fluid duct62includes nozzle66configured to direct reactant gas64to reactor section46and to provide a motive flow to create suction in suction chamber42. Nozzle66can have a converging shape configured to accelerate the flow of the reactant gas through the nozzle and increase the velocity of the reactant gas. Nozzle66can have outlet orifice68opening toward reactor section46to direct flow to catalyst60. The high velocity reactant gas reduces pressure in suction chamber42. A pressure differential created across recycle passage50causes higher pressure exhaust gas51at outlet34to enter recycle passage inlet56and flow toward lower pressure suction chamber42. The reactant gas enters suction chamber42at inlet53. The pressure differential created by motive fluid duct34provides for automatic recycle of exhaust gas51without the need for an external blower or pump. Delivery of the motive fluid can be controlled by controller24and one or more valves to increase or decrease the velocity of the reactant gas entering COU20′ and thereby recycle of exhaust gas51.

Reactant gas64provided as motive fluid in COU20′ is a mixture of fuel16and combustion air19with a predefined stoichiometric oxygen-to-fuel ratio, delivered through supply lines28and/or30(shown inFIG. 1). Reactant gas64can be cooled or heated via a heat exchanger or source of heat as known in the art (not shown) to obtain an optimal inlet gas temperature for reaction in COU20′.

Mixing region44is immediately upstream of reactor section46and is configured to mix reactant gas64with exhaust gas51to produce gaseous mixture58upstream of reactor section46. Gaseous mixture58enters reactor section46for catalytic reaction.

Reactor section46contains catalyst60. Catalyst60can be a monolithic solid body permeable to gaseous mixture58. In some embodiments, catalyst60can have a honeycomb-like structure suitable for providing a reactive surface area as known in the art. Catalyst60can consist of noble metals, transition metals, metal oxides, and combinations thereof. Both catalyst60and reactor section46can be cylindrical in shape with catalyst60closely fitted within reactor section46to prevent gaseous mixture58from bypassing catalyst60. Catalyst60can has a cross-sectional area substantially equal to an inner cross-sectional area of reactor section46or an outer diameter substantially equal to an inner diameter of reactor section46. In such configuration, gaseous mixture58is forced to flow through catalyst60. As shown inFIG. 3, catalyst60extends a full length of reactor section46. In a non-limiting example, catalyst60can be supported on a metallic or ceramic monolith substrate having a length ranging from 25 mm to 150 mm, diameter of 25 mm to 90 mm, and number of cells per square inch (CPSI) between 200 and 600 (31-93 cells per square centimeter).

As previously discussed, fuel16and combustion air19react in the presence of catalyst60to produce carbon dioxide and water. The addition of exhaust gas51can internally cool the reactor and minimize heat release within the reactor by reducing the amount of oxygen and fuel available for reaction, minimizing the difference between inlet and outlet reactant concentrations across catalyst60, and changing the residence time across catalyst60. Because the inert gases present in exhaust gas51(carbon dioxide, water, and nitrogen) do not react with catalyst60, no heat is generated by this portion of exhaust gas51flowing through catalyst60. The inert gas passes through catalyst60chemically unchanged, although it can absorb heat generated in reaction section46by the reaction of fuel16and combustion air19.

Exhaust gas51can be recycled at any given or predetermined ratio or percentage. In a non-limiting example, 95% of exhaust gas51may be recycled with only 5% being directed to ullage14or fire suppression systems. Alternatively, 5% of exhaust gas may be recycled with 95% being directed to ullage14or fire suppression systems. These values are merely examples. The amount of exhaust gas51recycled can be varied depending on a number of factors, including but not limited to, a desired reactor temperature during steady-state operation. In some embodiments, recycle can be passive with a recycle rate high as possible at all time, generally greater than 20:1. In alternative embodiments, the recycle rate can be controlled by varying the input pressure on an inlet side of the ejector via one or more control valves (e.g., varying the total flow rate of combustion air19).

Exhaust gas51is recycled through recycle passages50. Each recycle passage50includes inlet56and outlet53(suction chamber inlet53). Inlets56are positioned at outlet34of reactor section46. Inlets56can be evenly distributed about an inner wall of outlet56or arranged in any configuration suitable for delivering exhaust gas51to an inlet of catalyst60. Suction chamber inlets53can be evenly distributed about an inner wall of suction chamber42or can be arranged in any manner suitable to facilitate mixing in mixing region44. Generally, suction inlets53can be perpendicular to motive fluid duct outlet319. Recycle passages50can be made from aluminum, stainless steel, or other material suitable for delivering a pressurized and high-temperature gas. The portion of exhaust gas51not recycled through recycle passages50is delivered out of COU20′ through outlet34for fuel tank inerting and fire suppression applications.

Integrated reactor body37integrates recycle passage50and motive fluid duct62into COU20′ in a manner that allows a portion of exhaust gas51to be automatically recycled through reactor section46without use of an external blower.

The ejector-like reactor designs of COU20and COU20′ can be used to manage heat generation in catalytic oxidation while eliminating the need for an external recycle device. By placing catalyst60inside an ejector body36,37, exhaust gas51is automatically recycled back through catalyst60.

Summation

Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally”, “approximately” and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, transient alignment or shape variations induced by thermal, rotational or vibrational operational conditions, and the like. Moreover, any relative terms or terms of degree used herein should be interpreted to encompass a range that expressly includes the designated quality, characteristic, parameter or value, without variation, as if no qualifying relative term or term of degree were utilized in the given disclosure or recitation.

Discussion of Possible Embodiments

An internal recycle reactor for catalytic inerting has a monolithic body having a motive fluid duct, a suction chamber, a mixing region, a reactor section, an outlet, and a recycle passage. The suction chamber includes a suction chamber inlet. The mixing region is configured to receive gaseous fluids from the motive fluid duct and the suction chamber inlet to produce a gaseous mixture. The reactor section includes a catalyst and is configured to receive the gaseous mixture from the mixing region. The outlet is configured to deliver an exhaust gas from the reactor section and the recycle passage is configured to deliver a portion of the exhaust gas to the suction chamber inlet.

The internal recycle reactor of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components:

The internal recycle reactor of the preceding paragraph, wherein the motive fluid duct can include a converging nozzle configured to direct a reactant gas to the reactor section.

The internal recycle reactor of any of the preceding paragraphs, wherein the suction chamber inlet can be disposed perpendicular to an outlet orifice of the nozzle.

The internal recycle reactor of any of the preceding paragraphs can further include a reactant fluid inlet disposed upstream of the catalyst. The motive fluid duct can be configured to deliver a bleed air and the reactant fluid inlet can be configured to deliver a fuel.

The internal recycle reactor of any of the preceding paragraphs, wherein the catalyst can be a solid body permeable to the gaseous mixture and wherein the catalyst fills a cross-sectional area of the reactor section with the cross-section taken along a plane perpendicular to a length of the reactor section.

The internal recycle reactor of any of the preceding paragraphs, wherein the catalyst can fill the cross-sectional area over the entire length of the reactor section.

The internal recycle reactor of any of the preceding paragraphs, wherein the catalyst can comprise a material selected from the group consisting of noble metals, transition metals, metal oxides, and combinations thereof.

An internal recycle reactor for catalytic inerting includes an ejector and a recycle passage. The ejector includes a motive fluid duct, a suction chamber having a suction chamber inlet, a mixing region, a reactor section, and an outlet. The mixing region is configured to receive gaseous fluids from the motive fluid duct and the suction chamber inlet and to produce a gaseous mixture. The reactor section is positioned to receive the gaseous mixture from the mixing region and configured to react with the gaseous mixture and the outlet is configured to deliver an exhaust gas from the reactor section. The recycle passage extends from the outlet to the suction chamber inlet and is configured to deliver a portion of the exhaust gas to the suction chamber inlet.

The internal recycle reactor of any of the preceding paragraphs, wherein the motive fluid duct can include a converging nozzle configured to direct a reactant gas to the catalyst.

The internal recycle reactor of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components:

The internal recycle reactor of the preceding paragraph, wherein the suction chamber inlet can be perpendicular to an outlet orifice of the converging nozzle.

The internal recycle reactor of any of the preceding paragraphs, wherein the catalyst can fill a cross-sectional area of the reactor section to prevent the gaseous mixture from bypassing the catalyst with cross-section taken along a plane perpendicular to a length of the reactor section.

The internal recycle reactor of any of the preceding paragraphs, wherein the catalyst comprises a material selected from the group consisting of noble metals, transition metals, metal oxides, and combinations thereof.

A method of catalytic inerting includes flowing a reactant gas to a first inlet of an ejector, flowing a portion of an exhaust gas from an ejector outlet to a second inlet of the ejector, mixing the reactant gas with the exhaust gas to produce a gaseous mixture, flowing the gaseous mixture through a catalyst disposed in the ejector, and flowing the exhaust gas from the catalyst to an outlet.

The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, additional components, and/or steps:

The method of any of the preceding paragraphs, wherein the reactant gas can provide a motive flow that drives the flow of the exhaust gas into the second inlet by suction.

The method of any of the preceding paragraphs, wherein the reactant gas can be a mixture of fuel and air.

The method of any of the preceding paragraphs, wherein the reactant gas can be air and wherein the method further comprises injecting a fuel into the mixing region.

The method of any of the preceding paragraphs can further include reacting the gaseous mixture with the catalyst to produce an inert gas with the exhaust gas comprising the inert gas.