IP Library › Granted Patent US 12,546,252
Granted Patent B2
US 12,546,252 · App. 19/092,045 · Granted Feb 10, 2026

Integrated gas turbine cycle and liquid air energy conversion system

Inventor: Henry E. Howard (Grand Island, NY)
Assignee: Praxair Technology, Inc.
F02C6/18F01K23/10F01K25/10F02C6/16F02C7/08F25J2240/80Y02P80/10
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Quick Facts
Patent No.
US 12,546,252
App. No.
19/092,045
Granted
Feb 10, 2026
Kind
B2
Abstract

An integrated gas turbine cycle and liquid air energy conversion system is provided that utilizes very high pressure air stream(s) produced from vaporization of a supercritical liquid air against a low pressure cryogenic gas. The cooled, low pressure cryogenic gas is then cold compressed to yield a moderate pressure cryogenic gas stream(s). Both the very high pressure air stream(s) and the moderate pressure air stream(s) are warmed in the flue gas heat exchanger associated with the gas turbine cycle. A source of electrical power is produced from the expansion of combustion gas in a gas turbine while auxiliary sources of electrical power are produced from the turbine expansion of the warmed very high pressure air streams and moderate pressure cryogenic gas streams. The combustion gas includes a moderate pressure supplemental stream originating from the supercritical liquid air or from the cold compressed cryogenic gas.

Claims (44)

1 . A method of energy recovery from liquid air, comprising the steps of:

(a) receiving one or more very high pressure air streams from vaporization of the liquid air;

(b) receiving one or more moderate pressure cryogenic gas streams;

(c) expanding a stream of combustion gas to yield a flue gas exhaust stream and shaft work used to create a first source of electrical power;

(d) cooling the flue gas exhaust stream to yield a cooled waste stream via indirect heat exchange with: (i) all of or a portion of the one or more very high pressure air streams to yield a first warmed stream; and (ii) all of or a portion of the one or more moderate pressure cryogenic gas streams to yield a second warmed stream;

(e) expanding the first warmed stream in a first turbine-expander configured to produce a first moderate pressure exhaust stream and shaft work used to create a second source of electrical power; and

(f) expanding the second warmed stream or the first moderate pressure exhaust stream in a second turbine-expander to produce a second moderate pressure exhaust stream and shaft work used to create a third source of electrical power;

wherein the combustion gas is produced from the combustion of a fuel source with one or more oxygen containing streams, and wherein at least one of the oxygen containing streams is a moderate pressure supplemental stream; and

wherein the one or more moderate pressure cryogenic gas streams comprises a pre-purified air stream at a pressure in the range of about 3 bar (a) to 10 bar (a) and that has a normal boiling point equal to or less than −150° C.

2 . The method of claim 1 , wherein the second warmed stream is expanded in the second turbine-expander and the method further comprising the steps of:

(g) warming a first exhaust stream in a flue gas heat exchanger;

(h) expanding the warmed first exhaust stream to produce a third exhaust stream and shaft work used to create a fourth source of electrical power.

3 . The method of claim 1 , wherein the moderate pressure supplemental stream is all or a portion of the first moderate pressure exhaust stream.

4 . The method of claim 1 , wherein the moderate pressure supplemental stream is all or a portion of the second moderate pressure exhaust stream.

5 . The method of claim 1 , wherein the moderate pressure supplemental stream is a mixture of two or more streams selected from the group consisting of a portion of the first moderate pressure exhaust stream, a portion of the second moderate pressure exhaust stream, a portion of the one or more moderate pressure cryogenic gas streams; and a portion of the one or more very high pressure air streams.

6 . The method of claim 1 , wherein the one or more very high pressure air streams is hydrated with a source of water.

7 . The method of claim 1 , wherein the fuel source is natural gas or hydrogen or a mixture of hydrogen and natural gas.

8 . The method of claim 1 , wherein at least another one of the oxygen containing streams is a compressed air stream at a pressure in the range of 10 bar (a) to 50 bar (a).

9 . The method of claim 1 , further comprising the initial steps of:

pumping the liquid air to a supercritical pressure to yield a supercritical liquid air stream;

vaporizing the supercritical liquid air stream against a low pressure cryogenic gas stream to yield the one or more very high pressure air streams and a cooled, low pressure cryogenic gas; and

cold compressing the cooled, low pressure cryogenic gas to yield one of the one or more moderate pressure cryogenic gas streams.

10 . The method of claim 9 , wherein the cooled, low pressure cryogenic gas is all of or a portion of at least one of the one or more moderate pressure cryogenic gas streams.

11 . The method of claim 9 , wherein the moderate pressure supplemental stream is a portion of the one or more very high pressure air streams produced from vaporization of the supercritical liquid air stream that has been reduced in pressure.

12 . A method of energy recovery from liquid air, comprising the steps of:

(a) receiving one or more very high pressure air streams from vaporization of the liquid air;

(b) receiving one or more moderate pressure cryogenic gas streams;

(c) expanding a stream of combustion gas to yield a flue gas exhaust stream and shaft work used to create a first source of electrical power;

(d) cooling the flue gas exhaust stream to yield a cooled waste stream via indirect heat exchange with: (i) all of or a portion of the one or more very high pressure air streams to yield a first warmed stream; and (ii) all of or a portion of the one or more moderate pressure cryogenic gas streams to yield a second warmed stream;

(e) expanding the first warmed stream in a first turbine-expander configured to produce a first moderate pressure exhaust stream and shaft work used to create a second source of electrical power; and

(f) expanding the second warmed stream or the first moderate pressure exhaust stream in a second turbine-expander to produce a second moderate pressure exhaust stream and shaft work used to create a third source of electrical power;

wherein the combustion gas is produced from the combustion of a fuel source with one or more oxygen containing streams, and wherein at least one of the oxygen containing streams is all or a portion of the first moderate pressure exhaust stream.

13 . The method of claim 12 , further comprising the initial steps of:

pumping the liquid air to a supercritical pressure to yield a supercritical liquid air stream;

vaporizing the supercritical liquid air stream against a low pressure cryogenic gas stream to yield the one or more very high pressure air streams and a cooled, low pressure cryogenic gas; and

cold compressing the cooled, low pressure cryogenic gas to yield one of the one or more moderate pressure cryogenic gas streams.

14 . The method of claim 12 , wherein the second warmed stream is expanded in the second turbine-expander and the method further comprising the steps of:

(g) warming a first exhaust stream in a flue gas heat exchanger; and

(h) expanding the warmed first exhaust stream to produce a third exhaust stream and shaft work used to create a fourth source of electrical power.

15 . The method of claim 12 , wherein the one or more moderate pressure cryogenic gas streams comprises a gas that has a normal boiling point equal to or less than −150° C.

16 . The method of claim 15 , wherein the one or more moderate pressure cryogenic gas streams comprise a pre-purified air stream at a pressure in the range of about 3 bar (a) to 10 bar (a).

17 . The method of claim 12 , wherein the one or more very high pressure air streams is hydrated with a source of water.

18 . The method of claim 12 , wherein the fuel source is natural gas or hydrogen or a mixture of hydrogen and natural gas.

19 . The method of claim 12 , wherein at least another one of the oxygen containing streams is a compressed air stream at a pressure in the range of 10 bar (a) to 50 bar (a).

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 27, 2025
From: HOWARD, HENRY E.
To: PRAXAIR TECHNOLOGY, INC.
Reel/Frame 070647/0331 →
Continuity (2)
Provisional Application 63678175 · Aug 1, 2024
Related Publication 20260036081A1 · Feb 5, 2026
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