US-20260126009-A1 - DILUTE COMBUSTION OF HYDROGEN IN RETROFITTED GAS TURBINE ENGINES

Abstract

Various embodiments are provided related to improved gas turbine engine systems. In one example, a system is provided which includes a gas turbine engine having an air inlet stream, a hydrogen fuel supply, and an exhaust stream. The system further includes a heat exchanger configured to cool the exhaust stream from the gas turbine engine. The system can additionally include a recirculation pathway configured to mix the cooled exhaust stream from the heat exchanger with the air inlet stream.

Inventors

• William E. Lear

Assignees

• UNIVERSITY OF FLORIDA RESEARCH FOUNDATION, INC.

Dates

Publication Date

20260507

Application Date

20240104

Claims (14)

1. 1 . A system, comprising: a gas turbine engine having an air inlet stream, a hydrogen fuel supply, and an exhaust stream; a heat exchanger configured to cool the exhaust stream from the gas turbine engine; and a recirculation pathway configured to mix the cooled exhaust stream from the heat exchanger with the air inlet stream.
2. 2 . The system of claim 1 , further comprising: a heat recovery unit positioned between the gas turbine engine and the heat exchanger, the heat recovery unit configured to at least: receive the exhaust stream of the gas turbine engine; cool the exhaust stream; and output the cooled exhaust stream to the heat exchanger.
3. 3 . The system of claim 1 , further comprising: a cooler positioned between the heat exchanger and the air inlet stream, the cooler configured to further cool air exiting the heat exchanger before mixing the cooled exhaust stream with the air inlet stream.
4. 4 . The system of claim 3 , wherein the cooler outputs water as a by-product of cooling.
5. 5 . The system of claim 3 , further comprising: a chiller configured to cool an exiting air stream from the heat exchanger to generate a cool air stream and configured to return the cool air stream to the air inlet stream.
6. 6 . The system of claim 5 , wherein the chiller returns cool air to the cooler for further cooling.
7. 7 . The system of claim 5 , wherein the chiller is at least one of an adsorption chiller or an absorption chiller.
8. 8 . A method, comprising: diluting an air inlet stream for a gas turbine engine with an exhaust gas recirculation stream; providing a hydrogen fuel supply to the gas turbine engine; combusting the air inlet stream and hydrogen fuel supply to produce energy and an exhaust stream; and cooling the exhaust stream with a heat exchanger to produce the gas recirculation stream.
9. 9 . The method of claim 8 , wherein the hydrogen fuel supply is pure hydrogen.
10. 10 . The method of claim 8 , wherein the hydrogen fuel supply is 50 to 100% hydrogen.
11. 11 . The method of claim 8 , wherein cooling the exhaust stream further comprises: using a heat recovery unit to remove heat from the exhaust stream of the gas turbine engine; and directing the cooled exhaust stream to the heat exchanger for further cooling.
12. 12 . The method of claim 8 , wherein cooling the exhaust stream further comprises: using a chiller to cool an output from the heat exchanger; and adding the cooled output to the gas recirculation stream.
13. 13 . The method of claim 8 , wherein cooling the exhaust stream further comprises: using a cooler to cool an output from the heat exchanger; and adding the cooled output to the gas recirculation stream.
14. 14 . The method of claim 8 , wherein cooling the exhaust stream further comprises: using a chiller to cool a first output from the heat exchanger; using a cooler to cool a second output from the heat exchanger; and adding the first cooled output and the second cooled output to the gas recirculation stream.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of co-pending U.S. provisional application entitled “DILUTE COMBUSTION OF HYDROGEN IN RETROFITTED GAS TURBINE ENGINES” having Ser. No. 63/478,556, filed on Jan. 5, 2023, which is hereby incorporated by reference in its entirety. BACKGROUND Combustion turbines can be used to generate mechanical power and/or electricity. To this end, a combustion turbine can ignite a mixture of fuel and air in order to drive a turbine shaft. A byproduct of the combustion can be the production of heat, water, and harmful pollutants such as nitric oxide and nitrogen dioxide (collectively, NOx). NOx gases are generated from combustion of fuels when nitrogen and oxygen react. The production of NOx increases at higher temperatures. If hydrocarbon resources are used to fuel the combustion, carbon dioxide will also be produced. Carbon dioxide contributes to the greenhouse effect, and as a result, climate change. The production of NOx and carbon dioxide are of significant environmental concern. SUMMARY Aspects of the present disclosure are related to retrofitting gas turbine engine systems to use hydrogen fuel without producing additional harmful nitrogen oxides (NOx) gases and without costly modification to existing systems. In one aspect, among others, a system comprises a gas turbine engine having an air inlet stream, a hydrogen fuel supply, and an exhaust stream; a heat exchanger configured to cool the exhaust stream from the gas turbine engine; and a recirculation pathway configured to mix the cooled exhaust stream from the heat exchanger with the air inlet stream. The system further comprises a heat recovery unit positioned between the gas turbine engine and the heat exchanger, where the heat recovery unit is configured to at least: receive the exhaust stream of the gas turbine engine; cool the exhaust stream; and output the cooled exhaust stream to the heat exchanger. The system further comprises a cooler positioned between the heat exchanger and the air inlet stream, where the cooler is configured to further cool air exiting the heat exchanger before mixing the cooled exhaust stream with the air inlet stream. In some aspects, the cooler outputs water as a by-product of cooling. In one or more aspects, the system further comprises a chiller configured to cool an exiting air stream from the heat exchanger to generate a cool air stream and configured to return the cool air stream to the air inlet stream. The chiller returns cool air to the cooler for further cooling in some aspects. The chiller can comprise at least one of an adsorption chiller or an absorption chiller. In another aspect, a method comprises diluting an air inlet stream for a gas turbine engine with an exhaust gas recirculation stream; providing a hydrogen fuel supply to the gas turbine engine; combusting the air inlet stream and hydrogen fuel supply to produce energy and an exhaust stream; and cooling the exhaust stream with a heat exchanger to produce the gas recirculation stream. In some aspects, the hydrogen fuel supply is pure hydrogen. In other aspects, the hydrogen fuel supply is 50 to 100% hydrogen. Cooling the exhaust stream can further comprise using a heat recovery unit to remove heat from the exhaust stream of the gas turbine engine; and directing the cooled exhaust stream to the heat exchanger for further cooling. According to various embodiments, cooling the exhaust stream further comprises using a chiller to cool an output from the heat exchanger; and adding the cooled output to the gas recirculation stream. In some aspects, cooling the exhaust stream further comprises: using a cooler to cool an output from the heat exchanger; and adding the cooled output to the gas recirculation stream. In some aspects, cooling the exhaust stream further comprises: using a chiller to cool a first output from the heat exchanger; using a cooler to cool a second output from the heat exchanger; and adding the first cooled output and the second cooled output to the gas recirculation stream. BRIEF DESCRIPTION OF THE DRAWINGS Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, with emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. FIG. 1 is a diagram of an example gas turbine engine system according to various embodiments of the present disclosure. FIG. 2 is a diagram of an example gas turbine engine system according to various embodiments of the present disclosure. FIG. 3 is a diagram of an example gas turbine engine system according to various embodiments of the present disclosure. FIG. 4 is a diagram of an example gas turbine engine system according to various embodiments of the present disclosure. FIG. 5 is a flowcha