Endothermic fuel system

Claim 3

The system of claim 1 further comprising means for combusting the reaction product stream.

Claim 4

The system of claim 1 wherein the heat source is compressor discharge air or ram air.

Claim 5

The system of claim 3 further comprising means for contacting the cooled heat source with an engine or airframe component that is hotter than the cooled heat source to cool the engine or airframe component.

Claim 6

The system of claim 1 wherein the heat source is an engine or airframe component.

Claim 7

The system of claim 1 wherein the catalyst is a zeolite that has an effective pore diameter of about 4 Å to about 8 Å and is a faujasite, chabazite, mordenite, or a silicalite.

Claim 8

The system of claim 1 wherein the liquid distillate hydrocarbon fuel comprises hydrocarbons selected from the group consisting of C 2 to C 20 normal paraffins, C 3 to C 20 isoparaffins, conventional aircraft turbine fuels, and mixtures thereof.

Claim 9

The system of claim 1 wherein the means for transferring thermal energy comprises a reaction zone containing the endothermic decomposition catalyst in direct thermal contact with the heat source.

Claim 10

The system of claim 1 wherein the means for transferring thermal energy comprises a heat transfer fluid selected form the group consisting of the hydrocarbon fuel, air, molten salt, and liquid metal.

Claim 11

The system of claim 1 wherein the means for contacting the heated catalyst with the liquid distillate hydrocarbon fuel are capable of establishing a liquid hourly space velocity of about 20 hr -1 to about 700 hr -1 .

Claim 14

The system of claim 11 wherein the heat source is compressor discharge air or ram air.

Claim 15

The system of claim 12 further comprising means for contacting the cooled heat source with an engine or airframe component that is hotter than the cooled heat source to cool the engine or airframe component.

Claim 16

The system of claim 11 wherein the heat source is an engine or airframe component.

Claim 17

An endothermic fuel system for cooling a combustion chamber wall of an aircraft engine or a ground-based gas turbine engine, comprising: (a) a reaction zone disposed in a combustion chamber wall of an aircraft engine or a ground-based gas turbine engine, wherein the reaction zone is in direct thermal contact with the combustion chamber wall, which is at a suitable temperature, such that thermal energy can flow directly from the combustion chamber wall to the reaction zone to cool the combustion chamber wall to a temperature less than its original temperature and heat the reaction zone to a temperature between about 400° F. and about 1500° F.; (b) an endothermic fuel decomposition catalyst positioned in the reaction zone such that the catalyst is at substantially the same temperature as the reaction zone, wherein the catalyst comprises a metal selected from the group consisting of nickel, cobalt, platinum, rhenium, rhodium, iridium, ruthenium, palladium, and mixtures thereof, or a zeolite and is capable of endothermically decomposing at least a portion of an endothermic fuel stream at a temperature between about 400° F. and about 1500° F.; and (c) means for directing the fuel stream into the reaction zone such that the fuel stream contacts the heated catalyst, absorbs a heat of reaction, and decomposes into a reaction product stream.

Claim 18

An endothermic fuel system for cooling a combustion chamber wall of an aircraft engine or a ground-based gas turbine engine, comprising: (a) a reaction zone disposed in a combustion chamber wall of an aircraft engine or a ground-based gas turbine engine, wherein the reaction zone is in direct thermal contact with the combustion chamber wall, which is at a suitable temperature, such that thermal energy can flow directly from the combustion chamber wall to the reaction zone to cool the combustion chamber wall to a temperature less than its original temperature and heat the reaction zone to a temperature between about 400° F. and about 1500° F.; (b) an endothermic fuel decomposition catalyst positioned in the reaction zone such that the catalyst is at substantially the same temperature as the reaction zone, wherein the catalyst comprises a metal selected from the group consisting of nickel, cobalt, platinum, rhenium, rhodium, iridium, ruthenium, palladium, and mixtures thereof, or a zeolite and is capable of endothermically decomposing at least a portion of an endothermic fuel stream at a temperature between about 400° F. and about 1500° F.; and (c) means for directing the fuel stream into the reaction zone such that the fuel stream contacts the heated catalyst, absorbs a heat of reaction, and decomposes into a reaction product stream.

Claim 19

The system of claim 15 wherein the catalyst is a zeolite that is capable of catalytically cracking the endothermic fuel stream into a reaction product stream with a conversion of greater than about 60% at a temperature between about 1100° F. and about 1500° F. to produce a total heat sink of at least about 2025 Btu/lb of fuel and the endothermic fuel comprises hydrocarbons selected from the group consisting of C 2 to C 20 normal paraffins, C 3 to C 20 isoparaffins, conventional aircraft turbine fuels, and mixtures thereof.

Claim 20

The system of claim 15, wherein the catalyst is in the form of pellets.

Claim 21

The system of claim 15, wherein the reaction zone has walls and the catalyst is a coating on the walls of the reaction zone.

Claim 22

The system of claim 15, wherein the reaction zone is in the form of a honeycomb.

Claim 23

An endothermic fuel system for indirectly cooling an engine or airframe component, comprising: (a) a reaction zone; (b) an endothermic fuel decomposition catalyst positioned in the reaction zone, wherein the catalyst comprises a metal selected from the group consisting of nickel, cobalt, platinum, rhenium, rhodium, iridium, ruthenium, palladium, mixtures thereof, or a zeolite and is capable of endothermically decomposing at least a portion of an endothermic fuel stream at a temperature between about 400° F. and about 1500° F.; (c) means for contacting the catalyst with the endothermic fuel stream; (d) means for transferring thermal energy from a compressor discharge air stream or a ram air stream, which is at a suitable temperature, to the reaction zone such that the reaction zone and the catalyst are heated to a temperature between about 400° F. and about 1500° F. and the air stream is cooled to a temperature less than its original temperature; and (e) means for contacting the cooled air stream with a first engine or airframe component that requires cooling to cool the first engine or airframe component.

Claim 24

An endothermic fuel system for indirectly cooling an engine or airframe component, comprising: (a) a reaction zone; (b) an endothermic fuel decomposition catalyst positioned in the reaction zone, wherein the catalyst comprises a metal selected from the group consisting of nickel, cobalt, platinum, rhenium, rhodium, iridium, ruthenium, palladium, mixtures thereof, or a zeolite and is capable of endothermically decomposing at least a portion of an endothermic fuel stream at a temperature between about 400° F. and about 1500° F.; (c) means for contacting the catalyst with the endothermic fuel stream; (d) means for transferring thermal energy from a compressor discharge air stream or a ram air stream, which is at a suitable temperature, to the reaction zone such that the reaction zone and the catalyst are heated to a temperature between about 400° F. and about 1500° F. and the air stream is cooled to a temperature less than its original temperature; and (e) means for contacting the cooled air stream with a first engine or airframe component that requires cooling to cool the first engine or airframe component.

Claim 25

The system of claim 20, wherein the catalyst is a zeolite that is capable of catalytically cracking the endothermic fuel stream into a reaction product stream with a conversion of greater than about 60% at a temperature between about 1100° F. and about 1500° F. to produce a total heat sink of at least about 2025 Btu/lb of fuel and the endothermic fuel stream comprises hydrocarbons selected from the group consisting of C 2 to C 20 normal paraffins, C 3 to C 20 isoparaffins, conventional aircraft turbine fuels, and mixtures thereof.

Claim 26

The system of claim 20, further comprising: (f) means for contacting the fuel stream with a second engine or airframe component that is hotter than the fuel stream before contacting the catalyst with the fuel stream to heat the fuel stream and cool the second engine or airframe component.

Claim 27

The system of claim 22, wherein the first engine or airframe component and the second engine or airframe component are both a wall of a combustion chamber.