CA2409700A1

CA2409700A1 - Semi-closed brayton cycle gas turbine power systems

Info

Publication number: CA2409700A1
Application number: CA002409700A
Authority: CA
Inventors: Roger E. Anderson; Fermin Viteri
Original assignee: Clean Energy Systems, Inc.; Roger E. Anderson; Fermin Viteri
Current assignee: Clean Energy Systems Inc
Priority date: 2000-05-12
Filing date: 2001-05-14
Publication date: 2001-11-29
Anticipated expiration: 2021-05-14
Also published as: CA2409700C; US6910335B2; US20020023423A1; US20020100271A1; US20040065088A1; US6637183B2; US20050236602A1; WO2001090548A1; AU2001276823A1; US6622470B2; US20020096660A1; US6824710B2

Abstract

A semi-closed combined cycle system (100) is provided which converts an open cycle gas turbine (10) into a non-polluting power system. The prior art gas turbine (10) includes a compressor (20) which compresses air (A') and combusts the air (A') with fuel. Combustion products form the exhaust (E') which is expanded through the turbine (40). The turbine (40) drives the compressor (20) and outputs power. The exhaust (E') exits the turbine (40) and can be routed through a heat recovery steam generator (50). The exhaust (E') is routed to a divider (110) which has two outlets including a return duct (120) and a separation duct (130). The return duct (120) routes a portion of exhaust (E') back to the compressor (20), and a duct (150) adds oxygen to the exhaust (E').

Claims

What is claimed is:

Claim 1 - A semi-closed Brayton cycle power generation system, comprising in combination:
a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port;
a turbine downstream of said combustor, said turbine having an input coupled to said combustor outlet port, an output for the combustion products entering said turbine at said input, and a power output;
uct downstream of said turbine, said return duct receiving at least a portion of the combustion products passing through said output of said turbine and extending to said inlet of said compressor;
a gaseous oxygen duct coupled to a source of oxygen and coupled to said return duct in a manner adding oxygen to the combustion products within said return duct; and said gaseous oxygen duct located upstream of said gas compressor, such that the oxygen from said gaseous oxygen duct enters said compressor inlet along with the combustion products.
Claim 2 - The system of Claim 1 wherein a divider is located at least partially upstream of said return duct and downstream of said turbine, said divider dividing a portion of the combustion products passing through said output .of said turbine into a separation duct separate from said return duct.
Claim 3 - The system of Claim 2 wherein said divider divides a homogeneous portion of the combustion products into said separation duct, such that relative amounts of constituents of the combustion products within said separation duct match relative amounts of constituents in said return duct downstream of said divider.
Claim 4 - The system of Claim 3 wherein said divider divides out at least about ten percent of the combustion products passing through said output of said turbine into said separation duct.
Claim 5 - The system of Claim 2 wherein a condenser is located downstream of said separation duct, said condenser including a gas outlet and a condensate outlet.
Claim 6 - The system of Claim 5 wherein at least a portion of gases exiting said condenser through said gas outlet enter a gas outlet compressor, said gas outlet compressor compressing the gases passing thereinto to a pressure sufficient to inject the gases into a terrestrial formation taken from the group of terrestrial formations including: underground fissures, deep ocean locations and at least partially depleted oil wells.
Claim 7 - The system of Claim 5 wherein said gas outlet includes an oxygen separator therein which separates at least a portion of oxygen passing through said gas outlet from at least some of the other gases within said gas outlet, and an excess oxygen return path leading from said oxygen separator to a location upstream of said gas compressor, such that said oxidizer port of said combustor can have excess oxygen delivered into said combustor compared to an amount of the fuel entering said combustor through said fuel port and the excess oxygen can either return through said return duct to said oxidizer port or through said oxygen separator of said gas outlet of said condenser to said oxidizer port and at least some of the excess oxygen in said system can remain in said sy
Claim 8 - The system of Claim 2 wherein said divider includes a flow rate control valve on said separation duct controlling an amount of combustion products passing through said separation duct at said divider.
Claim 9 - The system of Claim 8 wherein said flow rate control valve is pressure sensitive to maintain pressure within said return duct slightly greater than the pressure of the surrounding atmosphere.
Claim 10 - The system of Claim 1 wherein a heat recovery steam generator is located downstream of said output of said turbine and upstream of said return duct, said heat recovery steam generator transferring heat to a separate power generation system such that said semi-closed Brayton cycle power generation system with said separate power generation system is in the form of a combined cycle power generation system.
Claim 11 - The system of Claim 1 wherein a partial condenser is located between said output of said turbine and said inlet of said compressor, said partial condenser having a condensate water outlet for at least a portion of a water constituent of the combustion products, said condensate water outlet leading to said combustor along a path separate from said gas compressor, such that at least a portion of a water constituent of the combustion products downstream of the output of the turbine bypasses the gas compressor and is routed directly to said combustor.
Claim 12 - The system of Claim 1 wherein the combustion products entering said turbine include carbon dioxide and water with a carbon dioxide percentage of the combined carbon dioxide and water portion of the combustion products being between about fifty percent and about sixty percent carbon dioxide by weight and a water percentage of the combined carbon dioxide and water portion of the combustion products being between about forty percent and about fifty percent water by weight.
Claim 13 - The system of Claim 12 wherein said carbon dioxide percentage is about fifty-five percent carbon dioxide by weight and said water percentage is about forty-five percent water by weight.
Claim 14 - The system of Claim 12 wherein the oxidizer from the oxidizer port of the combustor has the same constituent percentages as constituent percentage of a gas entering said gas compressor, the oxidizer including at least about ten percent oxygen by weight, between about ten percent and about forty-five percent steam by weight and between about forty percent and about seventy~~~~~~ carbon dioxide by weight.
Claim 15 - The system of Claim 14 wherein said oxidizer includes about thirteen percent oxygen by weight, about thirty-nine percent steam by weight and about forty-eight percent carbon dioxide by weight.
Claim 16 - The system of Claim 14 wherein said oxidizer includes about sixteen percent oxygen by weight, about twenty-eight percent steam by weight and about fifty-six percent carbon dioxide by weight.
Claim 17 - The system of Claim 14 wherein said oxidizer includes about twenty percent oxygen by weight, about seventeen percent steam by weight and about sixty-three percent carbon dioxide by weight.
Claim 18 - The system of Claim 1 wherein said source of oxygen includes an air separation unit configured to separate at least a portion of oxygen within air surrounding the air separation unit and delivering the oxygen to said gaseous oxygen duct, at least a portion of power utilized by said air separation unit provided by said power output of said turbine.
Claim 19 - A method for modifying an open Brayton cycle gas turbine for use in a semi-closed Brayton cycle power generation system, including the steps of:
providing an open Brayton cycle gas turbine including:
a gas compressor having an inlet and an outlet;
a combustor downstream of the compressor, the combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to the compressor outlet and an outlet port for combustion products resulting from combustion of fuel from the source of fuel with oxidizer from the oxidizer port; and a turbine downstream of the combustor, the turbine having an input coupled to the combustor outlet port, an output for the combustion products entering the turbine at the input, and a power output;

routing at least a portion of the combustion products passing through the output of the turbine to the inlet of the compressor; and adding oxygen to the combustion products upstream of the inlet of the compressor, such that the oxygen enters the compressor along with the combustion products.
Claim 20 - The method of Claim 19 wherein said routing step includes the step of providing a return duct downstream of the turbine, the return duct receiving at least a portion of the combustion products passing through the output of the turbine and extending to the inlet of the compressor.
Claim 21 - The method of Claim 20 including the further step of dividing out a portion of the combustion products downstream of the turbine output into a separation duct separate from the return duct.
Claim 22 - The method of Claim 21 wherein said dividing step includes the step of keeping constituent percentages of the combustion products divided into the separation duct matching the constituent percentages of the combustion products remaining within the return duct.
Claim 23 - The method of Claim 21 wherein said dividing step divides at least ten percent of the combustion products leaving the output of the turbine into the separation duct.
Claim 24 - The method of Claim 19 including the further step of matching characteristics of a gas entering the compressor with characteristics of air.
Claim 25 - The method of Claim 24 wherein the gas entering the compressor includes between about ten percent and fifty percent steam by weight and between about thirty percent and eighty percent carbon dioxide by weight.
Claim 26 - The method of Claim 19 including the further step of separating at least a portion of a water constituent of the combustion products exiting the turbine through the output from remaining combustion products routed to the inlet of the compressor in said routing step; and directing the separated water portion of said separating step to the combustor in a manner bypassing the compressor.
Claim 27 - The method of Claim 19 including the further step of passing the combustion products through a heat recovery steam generator between the output of the turbine and the inlet of the compressor.
Claim 28 - A kit for modifying an open Brayton cycle gas turbine for use in a semi-closed Brayton cycle power generation system, the kit comprising in combination:

an open Brayton cycle gas turbine including:

a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port; and a turbine downstream of said combustor, said turbine having an input coupled to said combu~~~port, an output for the combustion products entering said turbine at said input, and a power output;

a divider downstream of said turbine, said divider having a separation duct and a return duct, at least a portion of the combustion products entering said divider diverted into said separation duct and at least a portion of the combustion products entering said divider directed into said return duct;

said return duct downstream of said divider, said return duct receiving at least a portion of the combustion products passing through said divider and extending to said inlet of said compressor;

a gaseous oxygen duct coupled to a source of oxygen and coupled to said return duct in a manner adding oxygen to the combustion products within said return duct;

an air separation unit configured to separate at least a portion of oxygen within air surrounding the system to provide said source of oxygen; and said gaseous oxygen duct located upstream of said gas compressor and downstream of said divider, such that the oxygen from said gaseous oxygen duct enters said compressor inlet along with the combustion products.
Claim 29 - The kit of Claim 28 wherein said separation duct leads to a condenser, said condenser including a gas outlet and a condensate outlet.
Claim 30 - The kit of Claim 29 wherein said gas outlet includes an oxygen separator thereon and an oxygen recirculation line extending between said oxygen separator and a location upstream of said gas compressor, such that any excess oxygen in the combustion products passing through said separator duct can be captured by said oxygen separator and recirculated through said compressor and to said combustor for use in generating the combustion products.
Claim 31- The kit of Claim 29 wherein said divider includes a control valve, said control valve adjustable to control a flow rate of combustion products passing through said separation duct and said return duct.
Claim 32 - The kit of claim 28 wherein a partial condenser is located between said output of said turbine and said inlet of said gas compressor, said partial condenser having a condensate water outlet for at least a portion of a water constituent of the combustion products, said condensate water outlet leading to said combustor along a path separate from said gas compressor, such that at least a portion of a water constituent of the combustion products downstream of the output of the turbine bypasses the gas compressor and is routed directly to said combustor.
Claim 33 - A semi-closed Brayton cycle power generation system, comprising in combination:
~pressor having an inlet and an outlet;

a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port;

a turbine downstream of said combustor, said turbine having an input coupled to said combustor outlet port, an output for the combustion products entering said turbine at said input, and a power output;

a partial condenser downstream of said turbine output and upstream of said gas compressor inlet, said partial condenser condensing at least a portion of a water constituent of the combustion products, said partial condenser having a condensed water outlet;

an injection line downstream of said condensed water outlet and upstream of said combustor, said injection line bypassing said gas compressor; and a gaseous oxygen duct coupled to a source of oxygen and a location upstream of said gas compressor, such that the oxygen from said gaseous oxygen duct enters the compressor inlet along with at least a portion of the combustion products passing through said partial condenser.
Claim 34 - The system of Claim 33 wherein a return duct extends between said combustion products output of said turbine and said inlet of said gas compressor, said return duct routing at least a portion of the combustion products passing through said output of said turbine back to said inlet of said gas compressor.
Claim 35 - The system of Claim 34 wherein said partial condenser is located along a portion of said return duct such that at least a portion of the combustion products pass through both said return duct and said partial condenser as the combustion products pass from said output of said turbine to said inlet of said gas compressor.
Claim 36 - The system of Claim 34 wherein said partial condenser is located parallel to and at least partially separate from said return duct, such that only a portion of the combustion products exiting said output of said turbine pass through said partial condenser before continuing on to said inlet of said gas compressor.
Claim 37 - The system of Claim 33 wherein said gaseous oxygen duct delivers at least a portion of the oxygen from said source of oxygen to a location upstream of said partial condenser.
Claim 38 - The system of Claim 33 wherein said gaseous oxygen duct delivers at least a portion of the oxygen from said source of oxygen to a location downstream of said partial condenser.
Claim 39 - The system of Claim 33 wherein said combustor includes a water injection port, said injection line coupled to said water injection port such that water entering said injection line from said partial condenser is routed to said combustor through said water injection port.
Claim 40 - The system of Claim 39 wherein said injection line includes a pump for enhancing a pressure of water within said injection line and a heater for heating the water within said injection line into steam before delivering the water in the form of steam to said water injection port.
Claim 41 - The system of Claim 40 wherein said heater on said injection line is a heat recovery steam generator receiving heat from combustion products exiting said output of said turbine.
Claim 42 - The system of Claim 32 wherein a divider is located downstream of said output of said turbine and upstream of said gas compressor, said divider routing at least a portion of the combustion products passing through said output of said turbine to a separation duct leading at least a portion of the combustion products away from said gas compressor.
Claim 43 - The system of Claim 42 wherein a condenser is located downstream of said separation duct, said condenser including a condensate outlet, said condensate outlet at least partially coupled to said combustor along,a path bypassing said gas compressor.
Claim 44 - The system of Claim 33 wherein said partial condenser is configured to remove sufficient water from the combustion products and the gaseous oxygen duct adds sufficient oxygen upstream of said inlet of said gas compressor that a gas entering said inlet of said compressor includes between about ten percent and about thirty percent oxygen by weight, between about ten percent and fifty percent water by weight and between about forty percent and eighty percent carbon dioxide by weight.
Claim 45 - The system of Claim 44 wherein said partial condenser and said gaseous oxygen duct are configured to cause the gas entering said inlet of said compressor to include between about sixty percent carbon dioxide and about sixty-five percent carbon dioxide by weight, between about fifteen percent and about twenty percent water by weight and between about fifteen percent and about twenty-five percent oxygen by weight.
Claim 46 - A method for modifying an open Brayton cycle gas turbine with steam injection so that it can be used in a semi-closed Brayton cycle power generation system, including the steps of:
~~~~providing an open Brayton cycle gas turbine with steam injection including:
~~~~a gas compressor having an inlet and an outlet;
~~~~ibustor downstream of the compressor, the combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to the compressor outlet, a steam port coupled to a source of steam and an outlet port for combustion products resulting from combustion of fuel from the source of fuel with oxidizer from the oxidizer port; and a turbine downstream of the combustor, the turbine having an input coupled to the combustor outlet port, an output for the combustion products entering the turbine at the input, and a power output;

routing at least a portion of the combustion products passing through the output of the turbine to the inlet of the compressor; and adding oxygen to the combustion products upstream of the inlet of the compressor, such that the oxygen enters the compressor along with the combustion products.
Claim 47 - The method of Claim 46 including the further step of condensing at least a portion of a water constituent of the combustion products;

boiling at least a portion of the water condensed during said condensing step;
and feeding at least a portion of the boiled water from said boiling step to the steam port of the combustor.
Claim 48 - The method of Claim 47 wherein said boiling step includes the step of pumping the water condensed during said condensing step to a higher pressure and heating the water condensed during said condensing step with heat from the combustion products exiting the output of the turbine.
Claim 49 - The method of Claim 47 including the further step of dividing a portion of the combustion products exiting the output of the turbine to a separation duct, said condensing step occurring with the combustion products routed through the separation duct.
Claim 50 - The method of Claim 47 including the further step of interposing a partial condenser between the combustion products output of the turbine and the inlet of the compressor so that at least a portion of the combustion products pass through the partial condenser during the routing step, the partial condenser including a condensate outlet leading to the steam port of the combustor along a path bypassing the gas compressor.
Claim 51 - The method of Claim 50 including the step of fashioning a gas mixture entering the inlet of the gas compressor to include between about forty percent and about eighty percent carbon dioxide by weight, between about ten percent and about fifty percent water by weight and between about ten percent and about thirty percent oxygen by weight.
Claim 52 - The method of Claim 51 wherein said fashioning step includes the step of fashioning the gas mixture entering the inlet of the gas compressor to include about sixty-three percent carbon dioxide by weight, about seventeen percent water by weight and about twenty percent oxygen by weight.
Claim 53 - The method of Claim 46 wherein said adding step includes the step of separating at least a portion of oxygen within air surrounding the power generation system.
Claim 54 - The method of Claim 53 wherein said adding step includes the further step of powering an air separation unit utilized in said separating step of said adding step at least partially with power from the power output of the turbine.
Claim 55 - A kit for modifying an open Brayton cycle gas turbine with steam injection so that it can be used in a semi-closed Brayton cycle power generation system, comprising in combination:

an open Brayton cycle gas turbine with steam injection including:
a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet, a steam port coupled to a source of steam and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port; and a turbine downstream of said combustor, said turbine having an input coupled to said combustor outlet port, an output for the combustion products entering said turbine at said input, and a power output;

a return duct downstream of said turbine, said return duct receiving at least a portion of the combustion products passing through said output of said turbine and extending to said inlet of said compressor;

a gaseous oxygen duct coupled to a source of oxygen and coupled to said return duct in a manner adding oxygen to the combustion products within said return duct; and said gaseous oxygen duct located upstream of said gas compressor, such that the oxygen from said gaseous oxygen duct enters said compressor inlet along with at least a portion of the combustion products from said turbine output.
Claim 56 - The kit of Claim 55 wherein a partial condenser is located downstream of said combustion products output of said turbine, said partial condenser including a condensate water outlet, said condensate water outlet coupled to a water injection line leading to said steam port of said combustor along a path bypassing said gas compressor.
Claim 57 - The kit of Claim 56 wherein a divider is located downstream of said combustion products output of said turbine, said divider including a separation duct diverting at least a portion of the combustion products exiting the output of the turbine away from said return duct, said separation duct leading to a condenser, said water injection line at least partially fed by water condensed from said condenser in said separation duct.
Claim 58 - The kit of Claim 56 wherein said partial condenser is located within said return duct.
Claim 59 - The kit of Claim 57 wherein said partial condenser condenses only a portion of the water constituent of the combustion products entering said partial condenser.
Claim 60 - The kit of Claim 59 wherein said water injection line passes through a heat exchanger receiving heat from the combustion products exiting the output of said turbine with sufficient heat transfer to boil at least a portion of the water within said water injection line into steam.
Claim 61 - The kit of Claim 60 wherein said source of oxygen of said gaseous oxygen duct includes an air separation unit configured to separate at least a portion of oxygen out of air surrounding the system, said air separation unit receiving at least some power for separation of the oxygen from the air from said power output of said turbine.
Claim 62 - A semi-closed Brayton cycle power generation system, comprising in combination:
a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port;

an expander downstream of said combustor, said expander having an input coupled to said combustor outlet port, an output for the combustion products entering said expander at said input, and a power output;

means to return at least a portion of the combustion products passing through said output of said turbine to said gas compressor inlet;

means to separate oxygen from air surrounding said system; and means to add oxygen from said separating means to combustion products upstream of said gas compressor inlet, such that the oxidizer including oxygen from the oxygen separating means and the combustion products from said output of said expander are compressed by said gas compressor before entering said combustor at said oxidizer port.
Claim 63 - The system of Claim 62 including a means to divide at least a portion of the combustion products from the combustion products exiting said expander at said expander output, such that not all of the combustion products exiting said expander are routed back to said gas compressor.
Claim 64 - The system of Claim 63 including a condenser for at least a portion of a water constituent of the combustion products exiting said expander output, means to boil at least a portion of the water from said condenser and routing steam created by said boiling means to a steam port within said combustor along a path bypassing said gas compressor.
Claim 65 - A gas mixture for use as an oxidizer mixture portion of a working fluid in a gas turbine combustor, the mixture comprising in combination:

by weight between about forty percent and about eighty percent carbon dioxide, between about ten percent and about fifty percent water and between about ten percent and about thirty percent oxygen.
Claim 66 - The mixture of Claim 65 wherein said mixture includes by weight between about forty percent and about fifty-five percent carbon dioxide, between about thirty percent and about fifty percent water and between about ten percent and about twenty percent oxygen.
Claim 67 - The mixture of Claim 66 wherein said mixture includes by weight about forty-eight percent carbon dioxide, about thirty-nine percent water and about thirteen percent oxygen.
Claim 68 - The mixture of Claim 65 wherein said mixture includes by weight between about fifty percent and about sixty-two percent carbon dioxide, between about twenty percent and about thirty-five percent water and between about ten percent and twenty-five percent oxygen.
Claim 69 - The mixture of Claim 68 wherein said mixture includes by weight about fifty-six percent carbon dioxide, about twenty-eight percent water and about sixteen percent oxygen.
Claim 70 - The mixture of Claim 65 wherein said mixture includes by weight between about fifty percent and about eighty percent carbon dioxide, between about ten percent and thirty percent water and between about fifteen percent and about thirty percent oxygen.
Claim 71- The mixture of Claim 70 wherein said mixture includes by weight about sixty-three percent carbon dioxide, about seventeen percent water and about twenty percent oxygen.
Claim 72 - ~ gas mixture for use as an oxidizer mixture in a gas turbine combustor, the mixture comprising in combination:

a reactant portion;
a diluent portion;
said diluent portion including a set of diluent constituent chemical species;
said reactant portion including a set of reactant constituent chemical species;
said reactant portion able to react chemically with the fuel to produce a set of product constituent chemical species; and said set of product constituent chemical species and said set of diluent constituent chemical species having more species in common than species that are distinct between said set of diluent constituent chemical species and said set of product constituent chemical species.
Claim 73 - The mixture of Claim 72 wherein said set of diluent constituent chemical species and said set of product constituent chemical species are substantially similar.
Claim 74 - The mixture of Claim 73 wherein relative amounts of constituent chemical species within said set of diluent constituent chemical species are similar to relative amounts of product constituent chemical species within said set of product constituent chemical species.
Claim 75 - The mixture of Claim 74 wherein said set of product constituent chemical species includes carbon dioxide and water with carbon dioxide forming between about fifty percent and about sixty percent of said set of product constituent chemical species by weight and said water forming between about forty percent and about fifty percent of said set of product constituent chemical species by weight, and wherein said set of diluent constituent chemical species includes carbon dioxide and water with carbon dioxide forming between about fifty percent and about sixty percent by weight of said set of diluent constituent chemical species and said water forming between about forty percent and about fifty percent by weight of said set of diluent constituent chemical species.
Claim 76 - The mixture of Claim 75 wherein said set of product constituent chemical species includes about fifty-five percent carbon dioxide by weight and about forty-five percent water by weight, and wherein said set of diluent constituent chemical species includes about fifty-five percent carbon dioxide by weight and about forty-five percent water by weight.
Claim 77 - The mixture of Claim 72 wherein said reactant portion includes at least one oxygen containing species.
Claim 78 - The mixture of Claim 77 wherein said reactant portion includes gaseous oxygen molecule~~
Claim 79 - The mixture of Claim 78 wherein said reactant portion is substantially entirely gaseous molecular oxygen (O2).
Claim 80 - The mixture of Claim 72 wherein said fuel includes hydrogen and said set of product constituent chemical species includes water.
Claim 81 - The mixture of Claim 80 wherein said fuel includes a hydrocarbon therein and wherein said set of product constituent chemical species includes water and carbon dioxide.
Claim 82 - The mixture of Claim 81 wherein said fuel includes methane.
Claim 83 - The mixture of Claim 82 wherein said reactant portion is substantially entirely gaseous molecular oxygen (O2).
Claim 84 - A gas mixture for use as an oxidizer in a combustor of an at least partially closed cycle power generation system, the gas mixture comprising in combination:

molecular gaseous oxygen (O2);
gaseous carbon dioxide (CO2);
water vapor (H2O); and wherein a ratio of carbon dioxide to water within said gas mixture matches a ratio of carbon dioxide to water which occurs when methane (CH4) combusts with gaseous molecular oxygen (O2) substantially stoichiometrically.
Claim 85 - The mixture of Claim 84 wherein said mixture includes sufficient oxygen to cause said gas mixture to be compressible in a compressor designed to compress air without requiring compressor modification.
Claim 86 - The mixture of Claim 84 wherein said mixture includes by weight between about forty percent and about eighty percent carbon dioxide, between about ten percent and about fifty percent water vapor and between about ten percent and about thirty percent oxygen.
Claim 87 - The mixture of Claim 84 wherein said ratio of carbon dioxide to water is approximately one carbon dioxide molecule for every two water vapor molecules and about fifty-five percent of a combined weight of the carbon dioxide and the water is carbon dioxide and about forty-five percent of the combined weight of the carbon dioxide and the water is water.
Cla semi-closed Brayton cycle power generation system, comprising in combination:
a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port;
a turbine downstream of said combustor, said turbine having an input coupled to said combustor outlet port, an output for the combustion products entering said turbine at said input, and a power output;
a return duct downstream of said turbine, said return duct receiving at least a portion of the combustion products passing through said output of said turbine and extending to said inlet of said compressor;
a gaseous oxygen duct coupled to a source of oxygen and coupled to said return duct in a manner adding oxygen to the combustion products within said return duct; and said gaseous oxygen duct located upstream of said gas compressor, such that at least a portion of the oxygen from said gaseous oxygen duct enters said compressor inlet along with the combustion products.
Claim 89 - The system of Claim 88 wherein an air inlet duct is coupled to said return duct at a location upstream of said gas compressor.
Claim 90 - The system of Claim 89 wherein said air inlet duct has a valve thereon said valve capable of selectively opening and closing said air inlet duct.
Claim 91 - The system of Claim 90 wherein an outlet duct is located downstream of said turbine output, said outlet duct leading out of said system, such that when said air inlet duct is open and said outlet duct is open, said system can operate as an open Brayton cycle power generation system.
Claim 92 - The system of Claim 91 wherein a valve is located on said outlet duct.
Claim 93 - The system of Claim 92 wherein a heat recovery steam generator is located downstream of said turbine output, said heat recovery steam generator transferring heat out of the combustion products exiting said turbine output, said outlet duct located upstream of said heat recovery steam generator and downstream of said turbine output.
Claim 94 - The system of Claim 92 wherein a heat recovery steam generator is located downstream of said turbine output, said heat recovery steam generator transferring heat out of the combu ucts exiting said turbine output, said outlet duct located downstream of said heat recovery steam generator.
Claim 95 - A method for starting a semi-closed Brayton cycle power system including the steps of:
providing a semi-closed Brayton cycle power generation system including:
a gas compressor having an inlet and an outlet;
a combustor downstream of the compressor, the combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to the compressor outlet and an outlet port for combustion products resulting from combustion of fuel from the source of fuel with oxidizer from the oxidizer port;
a turbine downstream of the combustor, the turbine having an input coupled to the combustor outlet port, an output for the combustion products entering the turbine at the input, and a power output;
a return duct downstream of the turbine, the return duct receiving at least a portion of the combustion products passing through the output of the turbine and extending to the inlet of the compressor;
a gaseous oxygen duct coupled to a source of oxygen and coupled to the return duct in a manner adding oxygen to the combustion products within the return duct;
the gaseous oxygen duct located upstream of the gas compressor, such that at least a portion of the oxygen from the gaseous oxygen duct enters the compressor inlet along with the combustion products; and wherein an air inlet duct is coupled to the return duct at a location upstream of the gas compressor;
opening the air inlet duct so that air can pass into the return duct upstream of the compressor inlet;
keeping the oxygen duct initially closed;
starting the combustor, the turbine and the compressor of the semi-closed Brayton cycle power generation system;
opening the oxygen duct; and closing the air inlet duct.
Claim 96 - The method of Claim 95 including the further step of removing a nitrogen constituent of air entering the system at the air inlet duct during said opening step by including a divider downstream of the turbine output, the divider leading a portion of an exhaust from the turbine to a separation duct leading away from the inlet of the compressor, and allowing the nitrogen to gradually separate out of the system through the separation duct.
Cla he method of Claim 95 including the further step of providing an outlet duct, opening the outlet duct before said starting step; and closing the outlet duct after said starting step.
Claim 98 - A semi-closed Brayton cycle power generation system, comprising in combination:
a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port;
a turbine downstream of said combustor, said turbine having an input coupled to said combustor outlet port, an output for the combustion products entering said turbine at said input, and a power output;
a return duct downstream of said turbine, said return duct receiving at least a portion of the combustion products passing through said output of said turbine and extending to said inlet of said compressor;
a gaseous oxygen duct coupled to a source of oxygen and coupled to said return duct in a manner adding oxygen to the combustion products within said return duct;
said gaseous oxygen duct located upstream of said gas compressor, such that at least a portion of the oxygen from said gaseous oxygen duct enters said compressor inlet along with the combustion products;
said source of oxygen including an ion transfer membrane between an air inlet and an oxygen outlet, said oxygen outlet coupled to said gaseous oxygen duct; and an air heater between said air inlet and said membrane, said heater transferring heat from the combustion products downstream of said combustor into the air entering said air inlet.
Claim 99 - The system of Claim 98 wherein a diversion line is located downstream of said turbine output, said diversion line directing combustion products to said heater between said air inlet and said membrane.
Claim 100 -The system of Claim 98 wherein a heat recovery steam generator is located downstream of said turbine output, said heat recovery steam generator removing heat from the combustion products exiting said turbine output, said heat recovery steam generator heating water upstream of a steam turbine; and a diversion line diverting water between said heat recovery steam generator and said steam turbine to said heater between said air inlet and said membrane before said diversion line returns to said steam turbine.
Cla he system of Claim 98 wherein a heat recovery steam generator is located downstream of said turbine output, said heat recovery steam generator removing heat from the combustion products exiting said turbine output, said heat recovery steam generator heating water upstream of a steam turbine; and a diversion line extending from a location midway between an inlet of said steam turbine and an outlet of said steam turbine, said diversion line routed to said air heater between said air inlet and said membrane before said diversion line returns to said steam turbine.
Claim 102 -The system of Claim 98 wherein a partial condenser is located downstream of said turbine, said partial condenser including a condensate line for removal of condensed water out of said partial condenser, said condensation line routed to said combustor along a path bypassing said compressor, said path including a water preheater there along, said water preheater receiving heat from nitrogen discharged from said source of oxygen.
Claim 103 -The system of Claim 102 wherein said condensate line includes a second preheater receiving heat from oxygen discharged from said oxygen outlet of said source of oxygen between said membrane and said gaseous oxygen duct.
Claim 104 -The system of Claim 98 wherein a heat recovery steam generator is located downstream of said turbine output, said heat recovery steam generator removing heat from combustion products exiting said turbine output and adding heat to a bottoming cycle working fluid upstream of a bottoming cycle turbine, a diversion line downstream of said bottoming cycle turbine including a preheater thereon, said preheater heating the bottoming cycle working fluid with heat from hot gases exiting said source of oxygen before said bottoming cycle working fluid is routed back to said heat recovery steam generator.
Claim 105 -The system of Claim 98 including a heat recovery steam generator downstream of said turbine output, said heat recovery steam generator transferring heat from the combustion products exiting said turbine output to water in a bottoming cycle coupled to said heat recovery steam generator, said bottoming cycle including a gas generator having an oxygen inlet, a hydrocarbon fuel inlet and a water inlet, said water inlet coupled to said heat recovery steam generator to receive water from said heat recovery steam generator, said gas generator combusting said hydrocarbon fuel with said oxygen to produce combustion products including carbon dioxide and water, said bottoming cycle including an expander downstream of said gas generator and a condenser downstream of said expander, said condenser separating at least a portion of the water in the combustion products from a portion of the carbon dioxide in the combustion products, at least a portion of the water in the combustion products recirculated to said heat recovery steam generator.
Claim 106 -The system of Claim 105 wherein a compressor is located downstream of a gas outlet of said condenser, said compressor configured to compress gases including CO2 passing therethrough to sufficient pressure to allow injection of the gases including CO2 into a terrestrial formation for elimination of the CO2 from atmospheric release.
Claim 107 -The system of Claim 106 wherein said oxygen inlet of said gas generator is coupled to said oxygen outlet of said source of oxygen and wherein said source of oxygen includes a hot nitrogen outlet, and a heat exchanger between said hot nitrogen outlet and a condensate outlet of said condenser of said bottoming cycle, such that condensate from said condenser including water is preheated with heat from hot nitrogen exiting said source of oxygen.
Claim 108 -The system of Claim 107 wherein a heat exchanger is interposed between said air inlet and said membrane of said source of oxygen, said heat exchanger receiving heat from combustion products downstream of said gas generator of said bottoming cycle, the combustion products routed past said heat exchanger in heat transfer relationship with air between said air inlet and said membrane.
Claim 109 -A Brayton and Rankine combined cycle power generation system, comprising in combination:
a gas compressor having an inlet and an outlet;
a combustor downstream of said compressor, said combustor having a fuel port coupled to a source of fuel, an oxidizer port coupled to said compressor outlet and an outlet port for combustion products resulting from combustion of fuel from said source of fuel with oxidizer from said oxidizer port;

a turbine downstream of said combustor, said turbine having an input coupled to said combustor outlet port, an output for the combustion products entering said turbine at said input, and a power output;
a heat recovery steam generator downstream of said turbine output, said combustion products at least partially routed through said heat recovery steam generator;
a gas generator including an oxygen inlet, a hydrocarbon fuel inlet and a water inlet, said water inlet receiving water from a water path in said heat recovery steam generator in heat transfer contact with the combustion products from said turbine output routed through said heat recovery steam generator, such that the water entering said water inlet of aid gas generator is initially heated by the combustion products from said turbine output at said heat recovery steam generator, said gas generator combusting the hydrocarbon fuel with oxygen to produce a high temperature gas including carbon dioxide and water;
a bottoming cycle turbine located downstream of said gas generator and receiving the high temperature including carbon dioxide and water from said gas generator therein, said turbine outputting power from said system; and a condenser downstream of said bottoming cycle turbine, said condenser at least partially separating carbon dioxide from water in the gas exiting said turbine.
Claim 110 -The system of Claim 109 wherein a source of oxygen is coupled to said oxygen inlet of said gas generator, said source of oxygen including an air separation unit, such that the oxygen for the source of oxygen is separated from air.
Claim 111 -The system of Claim 110 wherein said air separation unit includes an air inlet and an ion transfer membrane downstream from said air inlet with an oxygen outlet downstream of said membrane and a nitrogen rich outlet downstream of said air inlet.
Claim 112 -The system of Claim 111 wherein a heater is located between said air inlet and said membrane, said heater configured to receive heat from combustion products downstream of said combustor.
Claim 113 -The system of Claim 111 wherein a heater is located between said air inlet and said membrane, said heater receiving heat transferred out of the combustion products passing through said heat recovery steam generator.
Claim 114 -The system of Claim 111 wherein a heater is located between said air inlet and said membrane, said heater receiving heat from a high temperature gas including carbon dioxide and water discharged from said gas generator.
Claim 115 -The system of Claim 110 wherein said source of oxygen feeds both said oxygen inlet of said gas generator and said oxidizer port of said combustor through said gas compressor.
Claim 116 -The system of Claim 115 wherein said air separation unit includes an air inlet and an ion transfer membrane downstream of said air inlet and an oxygen outlet downstream of said membrane, said oxygen outlet having a heat exchanger adjacent thereto configured to heat water passing through said heat exchanger.
Claim 117 -The system of Claim 116 wherein said water passing through said heat exchanger with oxygen from said oxygen outlet is routed into a steam injection line coupled to said combustor.
Claim 118 -The system of Claim 116 wherein said water passing through said heat exchanger is route id heat exchanger to said heat recovery steam generator for further heating of the water before entering said gas generator at said water inlet.
Claim 119 -The system of Claim 116 wherein a return duct is located downstream of said turbine, said return duct receiving at least a portion of the combustion products passing through said output of said turbine and extending to said inlet of said compressor, such that a semi-closed Brayton cycle is provided.
Claim 120 -The system of Claim 119 wherein a divider is located along said return duct, said divider dividing at least a portion of the combustion products into a separation duct leading out of the system.
Claim 121 -The system of Claim 120 wherein said return duct includes a partial condenser therein including a condensate line, said condensate line routed to said combustor along a path bypassing said compressor, such that at least a portion of water entering said return duct is routed directly to said combustor, said water injection line passing through a heater between said partial condenser and said combustor, said heater configured to receive heat from hot gases exiting said air separation unit.