Selectively deoxygenated stored fuel system

Patent metadata

Field	Value
Publication number	US-9863322-B2
Application number	US-201514599855-A
Country	US
Kind code	B2
Filing date	Jan 19, 2015
Priority date	Jan 23, 2014
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A gas turbine engine includes a multi-stage fuel injection system including at least a first fuel injection stage and a second fuel injection stage, a first fuel reservoir fluidly connected to the first fuel injection stage and fluidly connected to a selective valve, and a second fuel reservoir fluidly connected to the selective valve. The selective valve connects one of the first fuel reservoir and the second fuel reservoir to the second fuel injection stage.

First claim

The invention claimed is:

1. A gas turbine engine comprising:
a multi-stage fuel injection system including at least a first fuel injection stage and a second fuel injection stage;
a first fuel reservoir directly fluidly connected to the first fuel injection stage and fluidly connected to a selective valve;
a second fuel reservoir fluidly connected to the selective valve; and
wherein one of the first fuel reservoir and the second fuel reservoir is fluidly connected to the second fuel injection stage via the selective valve.

2. A gas turbine engine comprising:
a multi-stage fuel injection system including at least a first fuel injection stage and a second fuel injection stage;
a first fuel reservoir fluidly connected to the first fuel injection stage and fluidly connected to a selective valve;
a second fuel reservoir fluidly connected to the selective valve;
wherein one of the first fuel reservoir and the second fuel reservoir is fluidly connected to the second fuel injection stage via the selective valve; and
a controller controllably coupled to the selective valve, and wherein the controller is operable to control a state of the selective valve, the controller including a non-transitory memory storing instructions configured to cause the gas turbine engine to perform the steps of
transitioning from a first mode of engine operations to a second mode of engine operations by at least connecting a second fuel injector stage of a multi-stage fuel injection system to a de-oxygenated fuel reservoir;
operating said second fuel injector stage for at least a predefined time period, thereby ensuring that all fuel within the second fuel injector stage is de-oxygenated fuel; and
switching off the second fuel injector stage, thereby allowing de-oxygenated fuel to remain stagnant in the second fuel injector stage.

3. The gas turbine engine of claim 2 , further comprising a fuel de-oxygenation unit having a fuel outlet fluidly coupled to the second fuel reservoir.

4. The gas turbine engine of claim 3 , wherein a fuel inlet of said fuel de-oxygenation unit is fluidly coupled to the first fuel reservoir.

5. The gas turbine engine of claim 2 , wherein the selective valve fluidly couples the first fuel reservoir to the first fuel injection stage when the selective valve is in a first state, and wherein the selective valve fluidly connects the second fuel reservoir to the second fuel injection stage when the selective valve is in a second state.

6. The gas turbine engine of claim 2 , wherein said first fuel injection stage comprises a plurality of fuel injection nozzles, and wherein said second fuel injection stage comprises a plurality of fuel injection nozzles.

7. A method for preventing fuel coking in a multi-stage fuel injection system comprising:
transitioning from a first mode of engine operations to a second mode of engine operations by at least connecting a second fuel injector stage of a multi-stage fuel injection system to a de-oxygenated fuel reservoir;
operating said second fuel injector stage for at least a predefined time period, thereby ensuring that all fuel within the second fuel injector stage is de-oxygenated fuel; and
switching off the second fuel injector stage, thereby allowing de-oxygenated fuel to remain stagnant in the second fuel injector stage.

8. The method of claim 7 , further comprising:
de-oxygenating fuel from a main fuel reservoir using an on-board fuel de-oxygenation unit;
providing the de-oxygenated fuel from the on-board fuel de-oxygenation unit to the de-oxygenated fuel reservoir.

9. The method of claim 7 , wherein the step of connecting a second fuel injector stage of a multi-stage fuel injection system to a de-oxygenated fuel reservoir comprises controlling a state of a selective valve connected to an input of the second fuel injector stage.

10. The method of claim 9 , wherein operating the selective valve comprises switching the input of the selective valve from a main fuel reservoir to the de-oxygenated fuel reservoir.

11. The method of claim 9 , wherein the state of the selective valve is controlled by a controller.

12. The method of claim 7 , wherein switching off the second fuel injector stage, thereby allowing de-oxygenated fuel to remain stagnant in the second fuel injector stage to remain stagnant in the second fuel injector stage is performed while the second fuel injector stage is exposed to temperatures in excess of the coking temperature on non-de-oxygenated fuel.

13. A gas turbine fuel injection system comprising:
a first fuel injector stage having a plurality of fuel injector nozzles;
at least one additional fuel injector stage having a plurality of fuel injector nozzles;
a main fuel module connected to said first fuel injector stage via a main fuel line;
a selective valve having a first input, and second input and an output, the output of the selective valve being connected to the second fuel injector stage;
a de-oxygenated fuel reservoir connected to one of a first fuel input and a second fuel input, and the main fuel line being connected to the other of the first fuel input and the second fuel input; and
a controller coupled to the selective valve and operable to control a state of the selective valve, wherein the controller includes a non-transitory memory storing instructions configured to cause the fuel injection system to perform the steps of
transitioning from a first mode of engine operations to a second mode of engine operations by at least connecting a second fuel injector stage of a multi-stage fuel injection system to a de-oxygenated fuel reservoir;
operating said second fuel injector stage for at least a predefined time period, thereby ensuring that all fuel within the second fuel injector stage is de-oxygenated fuel; and
switching off the second fuel injector stage, thereby allowing de-oxygenated fuel to remain stagnant in the second fuel injector stage.

14. The gas turbine fuel injection system of claim 13 , wherein the controller is further controllably coupled to said main fuel module and is operable to control said main fuel module.

15. The gas turbine fuel injection system of claim 13 , wherein the main fuel module comprises at least a fuel pump and a main fuel reservoir.

16. The gas turbine fuel injection system of claim 13 , further comprising a fuel de-oxygenator fluidly coupled to said main fuel line such that at least a portion of fluid flowing through the main fuel line is diverted to said fuel de-oxygenator.

17. The gas turbine fuel injection system of claim 16 , wherein the fuel de-oxygenator comprises an output, and wherein the output is fluidly connected to the de-oxygenated fuel reservoir.

Assignees

• United Technologies Corp

Inventors

• Williams Alexander W
• Kramer Stephen K

Classifications

• F05D2260/607

  Preventing clogging or obstruction of flow paths by dirt, dust, or foreign particles · CPC title

• F23K5/08

  Preparation of fuel · CPC title

• Y02T50/675

  Cross-Sectional Technologies · mapped topic

• F23D2900/00016

  Preventing or reducing deposit build-up on burner parts, e.g. from carbon · CPC title

• Y02T50/671

  Cross-Sectional Technologies · mapped topic