Integrated production of oxygen and electric power

Claim 2

The method of Claim 1 which further comprises utilizing said shaft power in part to operate a first electric generator.

Claim 3

The method of Claim 2 which further comprises cooling said hot exhaust gas by indirect heat exchange with water to generate steam and expanding the steam through a steam turbine to operate a second electric generator.

Claim 4

The method of Claim 1 wherein said oxygen-enriched permeate stream is high purity oxygen containing at least 98 vol% oxygen.

Claim 5

The method of Claim 1 wherein said ion transport membranes comprise one or more mixed conductor membranes.

Claim 6

The method of Claim 1 wherein said ion transport membranes comprise one or more solid electrolyte membranes.

Claim 7

The method of Claim 1 which further comprises compressing a supplemental air stream and combining it with said second compressed air stream prior to heating in step (c).

Claim 8

The method of Claim 1 wherein the heating of said second compressed air stream in step (c) is accomplished by combusting said second compressed air stream with a second fuel in a second combustor to yield said hot oxygen-containing feed gas.

Claim 9

The method of Claim 1 wherein the heating of said second compressed air stream in step (c) is accomplished by indirect heat exchange with a hot combustion product to yield said hot oxygen-containing feed gas, wherein said hot combustion product is obtained by combusting said hot oxygen-depleted non-permeate stream with a second fuel in a second combustor.

Claim 10

The method of Claim 1 wherein the heating of said second compressed air stream in step (c) is accomplished by preheating said second compressed air stream by indirect heat exchange with said hot oxygen-depleted non-permeate stream and combusting the resulting preheated compressed air stream with a second fuel in a second combustor to yield said hot oxygen-containing feed gas.

Claim 11

The method of Claim 7 wherein the temperature, pressure, and molar flow rate of said combined hot gas stream of step (e) to said expansion turbine are maintained at fixed values by controlling the flow rate of said supplemental air stream and the firing rate of said first combustor.

Claim 12

The method of Claim 1 which further comprises compressing said second compressed air stream prior to step (c).

Claim 13

The method of Claim 1 which further comprises injecting water into said hot oxygen-depleted non-permeate stream, thereby cooling and increasing the molar flow rate of said stream, and introducing at least a portion of the resulting cooled stream into said first combustor.

Claim 14

The method of Claim 13 which further comprises preheating said water by indirect heat exchange with said hot oxygen-enriched permeate stream.

Claim 15

The method of Claim 3 which further comprises cooling said hot oxygen-enriched permeate stream by indirect heat exchange with water to generate steam and introducing the steam into the inlet of said steam turbine.

Claim 16

The method of Claim 3 which further comprises cooling said hot oxygen-depleted non-permeate stream by indirect heat exchange with water to generate additional steam and introducing this steam into the inlet of said steam turbine.

Claim 17

The method of Claim 16 which further comprises introducing at least a portion of the resulting cooled oxygen-containing non-permeate stream directly into said first combustor.

Claim 18

The method of Claim 16 which further comprises combining at least a portion of the resulting cooled oxygen-containing non-permeate stream with said first compressed air stream prior to said first combustor.

Claim 19

The method of Claim 8 wherein the temperature of said membrane separation zone is maintained at a temperature between 800 and 2,000°F by controlling the firing rate of said second combustor.

Claim 20

The method of Claim 1 wherein the flow rate of said second compressed air stream is up to 20% of the flow rate of said air feed stream.

Claim 21

In a combined cycle electric power generation system wherein feed air is compressed to yield a pressurized combustor feed which is heated in a gas turbine combustor fired by a turbine fuel, wherein the hot combustion product is expanded through an expansion turbine to generate shaft power which is used in part to compress said feed air and in part to drive an electric generator, and wherein hot exhaust gas from said expansion turbine is utilized to generate high pressure steam which is expanded through a steam turbine to drive another electric generator, a method to produce oxygen without affecting the level of power generation in said power generation system which comprises: (a) withdrawing a portion of said pressurized combustor feed; (b) combusting the portion of step (a) with fuel gas in a direct-fired combustor to produce a hot oxygen-containing combustion product; (c) passing said hot oxygen-containing combustion product into a membrane separation zone comprising one or more oxygen-selective ion transport membranes, and withdrawing therefrom a hot high-purity oxygen permeate stream and a hot oxygen-depleted non-permeate stream; and (d) injecting water into said hot oxygen-depleted non-permeate stream, thereby cooling said stream, and injecting at least a portion of the resulting cooled stream into said gas turbine combustor; wherein the temperature, pressure, and molar flow rate of the hot combustion product passing to said expansion turbine are maintained at fixed values by controlling the flow rate of said water in step (d) and the firing rate of said gas turbine combustor.

Claim 22

The method of Claim 21 which further comprises heating said water by indirect heat exchange with said hot high-purity oxygen permeate stream prior to injecting said water into said hot oxygen-depleted non-permeate stream.

Claim 23

The method of Claim 21 wherein the temperature of said membrane separation zone is maintained at a temperature between 800 and 2,000°F by controlling the firing rate of said direct-fired combustor independently of the firing rate of said gas turbine combustor.

Claim 24

The method of Claim 21 wherein the flow rate of said portion of pressurized combustor feed withdrawn in step (a) is up to 20% of the flow rate of said pressurized combustor feed.

Claim 25

In a combined cycle electric power generation system wherein feed air is compressed to yield a pressurized combustor feed which is heated in a gas turbine combustor fired by a turbine fuel, wherein the hot combustion product is expanded through an expansion turbine to generate shaft power which is used in part to compress said feed air and in part to drive an electric generator, and wherein hot exhaust gas from said expansion turbine is utilized to generate high pressure steam which is expanded through a steam turbine to drive another electric generator, a method to produce oxygen without affecting the level of power production in said power generation system which comprises: (a) withdrawing a portion of said pressurized combustor feed; (b) compressing a supplemental air stream and combining it with said portion of pressurized combustor feed; (c) combusting the combined compressed air stream of step (b) with fuel gas in a direct-fired combustor to produce a hot oxygen-containing combustion product; (d) passing said hot oxygen-containing combustion product into a membrane separation zone comprising one or more oxygen-selective ion transport membranes, and withdrawing therefrom a hot high-purity oxygen permeate stream and a hot oxygen-depleted non-permeate stream; and (e) combining said hot oxygen-depleted non-permeate stream with the hot combustion product from said gas turbine combustor prior to said expansion turbine; wherein the temperature, pressure, and molar flow rate of said combined hot gas stream of step (e) to said expansion turbine are maintained at fixed values by controlling the flow rate of said supplemental air stream and the firing rate of said gas turbine combustor.

Claim 27

The method of Claim 26 which further comprises cooling said hot exhaust gas by indirect heat exchange with water to generate steam and expanding the steam through a steam turbine to operate a second electric generator.

Claim 28

In a combined cycle electric power generation system wherein feed air is compressed to yield a pressurized combustor feed which is heated in a gas turbine combustor fired by a turbine fuel, wherein the hot combustion product is expanded through an expansion turbine to generate shaft power which is used in part to compress said feed air and in part to drive an electric generator, and wherein hot exhaust gas from said expansion turbine is utilized to generate high pressure steam which is expanded through a steam turbine to drive another electric generator, a method to reduce the concentration of NOx in said hot exhaust gas which comprises: (a) withdrawing a portion of gas from said pressurized combustor feed; (b) removing at least a portion of the oxygen from the withdrawn portion of gas of step (a) to yield an oxygen-depleted gas stream; and (c) combining said oxygen-depleted gas stream with the remainder of said pressurized combustor feed and introducing the combined stream into said gas turbine combustor; wherein the resulting reduced nitrogen concentration in the combined stream to said combustor reduces the formation of NOx in said combustor.

Claim 29

The method of Claim 28 wherein oxygen is removed from said withdrawn portion of gas in step (c) by heating said gas and passing the heated gas through an ion transport membrane zone to yield said oxygen-depleted gas stream.