# US 2014/0150445 A1 · System and method for load control with diffusion combustion in a stoichiometric exhaust gas recirculation gas turbine system

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- Number: US 2014/0150445 A1
- Document ID: US20140150445A1
- Status: Published application
- Kind: A1
- Application number: 14/067,563
- Filed: 2013-10-30
- Published: 2014-06-05
- Earliest claimed: 2012-11-02
- Assignees: ExxonMobil Upstream Research Company; General Electric Company
- Applicants: ExxonMobil Upstream Research Company; General Electric Company
- Inventors: Richard A. Huntington; Sulabh K. Dhanuka; Ilya Aleksandrovich Slobodyanskiy
- Web page: https://patentgrep.com/patent/US20140150445A1

## CPC

- F02C 3/34: with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle
- F02C 3/30: Adding water, steam or other fluids {for influencing combustion, e.g. to obtain cleaner exhaust gases (F02C7/141, F02C7/30, F01D21/00, F01K21/04, F23D11/10 take precedence)}
- F02C 7/228: Dividing fuel between various burners
- F02C 9/34: Joint control of separate flows to main and auxiliary burners
- F23R 3/28: characterised by the fuel supply (burners F23D)
- F23R 3/34: Feeding into different combustion zones
- F23R 3/346: {for staged combustion}
- F01K 23/10: with exhaust fluid of one cycle heating the fluid in another cycle (F01K17/025 takes precedence)
- F02C 1/06: using reheated exhaust gas (F02C1/08 takes precedence)
- F02C 3/22: the fuel or oxidant being gaseous at standard temperature and pressure (F02C3/28 takes precedence)
- F02C 6/18: using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants (using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10)
- F02C 9/28: Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed (F02C9/30 - F02C9/38, F02C9/44 take precedence)
- F05D 2270/08: to produce clean exhaust gases
- F05D 2270/0831: indirectly, at the exhaust
- F23C 9/00: Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber (fluidised bed combustion apparatus with means for recirculation of particles entrained from the bed F23C10/02; fluidised bed combustion apparatus with devices for removal and partial reintroduction of material from the bed F23C10/26)
- F23J 15/006: {Layout of treatment plant}
- F23J 15/02: of purifiers, e.g. for removing noxious material (traps for solid residues F23J3/04)
- F23J 2215/10: Nitrogen; Compounds thereof
- F23J 2215/40: Carbon monoxide
- F23J 2215/50: Carbon dioxide
- F23J 2219/10: Catalytic reduction devices
- F23N 1/022: {using electronic means}
- F23N 5/006: {the detector being sensitive to oxygen}
- F23R 3/26: Controlling the air flow
- Y02E 20/16: Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
- Y02E 20/32: Direct CO2 mitigation
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16)
- F01K: STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F23C: METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN {A CARRIER GAS OR} AIR (burners F23D)
- F23J: REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES (combustion apparatus for consuming smoke or fumes, e.g. exhaust gases, F23G7/06)
- F23N: REGULATING OR CONTROLLING COMBUSTION (control devices specially adapted for combustion apparatus in which combustion takes place in a fluidised bed of fuel or other particles F23C10/28; condition responsive controls for regulating combustion in domestic stoves with open fires for solid fuel F24B1/187)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A system is provided with a turbine combustor having a first diffusion fuel nozzle, wherein the first diffusion fuel nozzle is configured to produce a diffusion flame. The system includes a turbine driven by combustion products from the diffusion flame in the turbine combustor. The system also includes an exhaust gas compressor, wherein the exhaust gas compressor is configured to compress and route an exhaust gas from the turbine to the turbine combustor along an exhaust recirculation path. In addition, the system includes a control system configured to control flow rates of at least one oxidant and at least one fuel to the turbine combustor in a stoichiometric control mode and a non-stoichiometric control mode, wherein the stoichiometric control mode is configured to change the flow rates and provide a substantially stoichiometric ratio of the at least one fuel with the at least one oxidant, and the non-stoichiometric control mode is configured to change the flow rates and provide a non-stoichiometric ratio of the at least one fuel with the at least one oxidant.

## Claims

### Claim at position 1

1-232. (canceled)

### Claim 233

A system, comprising:
a turbine combustor comprising a first diffusion fuel nozzle, wherein the first diffusion fuel nozzle is configured to produce a diffusion flame;
a turbine driven by combustion products from the diffusion flame in the turbine combustor;
an exhaust gas compressor, wherein the exhaust gas compressor is configured to compress and route an exhaust gas from the turbine to the turbine combustor along an exhaust recirculation path; and
a control system configured to control flow rates of at least one oxidant and at least one fuel to the turbine combustor in a stoichiometric control mode and a non-stoichiometric control mode, wherein the stoichiometric control mode is configured to change the flow rates and provide a substantially stoichiometric ratio of the at least one fuel with the at least one oxidant, and the non-stoichiometric control mode is configured to change the flow rates and provide a non-stoichiometric ratio of the at least one fuel with the at least one oxidant.

### Claim 234 (depends on 233)

The system of claim 233, wherein the stoichiometric control mode is configured to provide the substantially stoichiometric ratio with an equivalence ratio of between approximately 0.95 and approximately 1.05, and wherein the non-stoichiometric control mode is configured to provide the non-stoichiometric ratio with an equivalence ratio of less than approximately 0.95 or greater than approximately 1.05.

### Claim 235 (depends on 233)

The system of claim 233, wherein the control system is configured to change the flow rates from a first set of flow rates to a second set of flow rates and transition between the stoichiometric control mode and the non-stoichiometric control mode.

### Claim 236 (depends on 233)

The system of claim 233, wherein the control system in the stoichiometric control mode is configured to change the flow rates from a first set of flow rates to a second set of flow rates while maintaining the substantially stoichiometric ratio.

### Claim 237 (depends on 236)

The system of claim 236, wherein the control system in the stoichiometric control mode is configured to change a power output of the turbine from a first power output to a second power output by changing the flow rates from the first set of flow rates to the second set of flow rates, respectively.

### Claim 238 (depends on 237)

The system of claim 237, wherein the second set of flow rates is less than the first set of flow rates, and the second power output is less than the first power output, or wherein the second set of flow rates is greater than the first set of flow rates, and the second power output is greater than the first power output.

### Claim 239 (depends on 237)

The system of claim 237, wherein the control system in the stoichiometric control mode is configured to maintain emissions in the exhaust gas within one or more target emissions ranges while changing the flow rates from the first set of flow rates to the second set of flow rates, wherein the one or more target emissions ranges comprise an oxygen range of less than approximately 50 parts per million by volume (ppmv) and/or a carbon monoxide range of less than approximately 5000 ppmv, or an oxygen range of less than approximately 10 parts per million by volume (ppmv) and/or a carbon monoxide range of less than approximately 1000 ppmv.

### Claim 240 (depends on 233)

The system of claim 233, wherein the control system in the stoichiometric control mode is configured to progressively change the flow rates among a plurality of sets of flow rates while maintaining the substantially stoichiometric ratio, wherein the plurality of sets of flow rates comprise at least three sets of flow rates, or at least four sets of flow rates.

### Claim 241 (depends on 240)

The system of claim 240, wherein the control system in the stoichiometric control mode is configured to maintain the substantially stoichiometric ratio while:
progressively reducing the flow rates among the plurality of sets of flow rates;
progressively reducing a power output of the turbine among a plurality of power outputs; and
maintaining emissions in the exhaust gas within one or more target emissions ranges.

### Claim 242 (depends on 241)

The system of claim 241, wherein the control system is configured to transition from the stoichiometric control mode to the non-stoichiometric control mode after progressively reducing the flow rates, progressively reducing the power output, and maintaining emissions.

### Claim 243 (depends on 242)

The system of claim 242, wherein, after the transition from the stoichiometric control mode to the non-stoichiometric control mode, the control system is configured to operate in a fuel rich control mode of the non-stoichiometric control mode, or a fuel lean control mode of the non-stoichiometric control mode.

### Claim 244 (depends on 233)

The system of claim 233, wherein the control system is configured to:
progressively change the flow rates among a plurality of sets of flow rates;
progressively change a power output of the turbine among a plurality of power outputs in response to the changes in flow rates;
maintain emissions in the exhaust gas within one or more target emissions ranges before and after the changes in flow rates;
maintain a temperature of the exhaust gas along the exhaust recirculation path within a target temperature range before and after the changes in flow rates; and
maintain a pressure of the exhaust gas along the exhaust recirculation path within a target pressure range before and after the changes in flow rates.

### Claim 245 (depends on 244)

The system of claim 244, wherein the control system is configured to maintain the pressure by adjusting at least one of an exhaust extraction valve, an exhaust vent valve, an operating speed of the exhaust gas compressor or an oxidant compressor, a position of an inlet guide vane of the exhaust gas compressor, a recycle valve of the exhaust gas compressor, or any combination thereof.

### Claim 246 (depends on 233)

The system of claim 233, wherein the turbine combustor comprises a first set of fuel nozzles coupled to a first fluid supply circuit and a second set of fuel nozzles coupled to a second fluid supply circuit, the first diffusion nozzle is part of either the first or second set of fuel nozzles, and the control system is configured to independently control fluid flows through the first and second fluid supply circuits.

### Claim 247 (depends on 246)

The system of claim 246, wherein the control system is configured to independently change the fluid flows through the first and second fluid supply circuits at different rates or at equal rates.

### Claim 248

A method, comprising:
injecting at least one oxidant and at least one fuel into a chamber of a turbine combustor, wherein the at least one oxidant and the at least one fuel mix and combust as a diffusion flame to generate combustion products;
driving a turbine with the combustion products and outputting an exhaust gas;
recirculating the exhaust gas along an exhaust recirculation path to an exhaust gas compressor;
compressing and routing the exhaust gas to the turbine combustor.
controlling flow rates of the at least one oxidant and the at least one fuel to the turbine combustor in a stoichiometric control mode, wherein the stoichiometric control mode is configured to change the flow rates and provide a substantially stoichiometric ratio of the at least one fuel with the at least one oxidant; and
controlling flow rates of the at least one oxidant and the at least one fuel to the turbine combustor in a non-stoichiometric control mode, wherein the non-stoichiometric control mode is configured to change the flow rates and provide a non-stoichiometric ratio of the at least one fuel with the at least one oxidant.

### Claim 249 (depends on 248)

The method of claim 248, wherein controlling in the stoichiometric control mode comprises providing the substantially stoichiometric ratio with an equivalence ratio of between approximately 0.95 and approximately 1.05, and wherein controlling in the non-stoichiometric control mode comprises providing the non-stoichiometric ratio with an equivalence ratio of less than approximately 0.95 or greater than approximately 1.05.

### Claim 250 (depends on 248)

The method of claim 248, wherein controlling in the stoichiometric control mode comprises changing the flow rates from a first set of flow rates to a second set of flow rates while maintaining the substantially stoichiometric ratio, wherein controlling in the stoichiometric control mode comprises changing a power output of the turbine from a first power output to a second power output by changing the flow rates from the first set of flow rates to the second set of flow rates, respectively.

### Claim 251 (depends on 250)

The method of claim 250, wherein the second set of flow rates is less than the first set of flow rates, and the second power output is less than the first power output, or wherein the second set of flow rates is greater than the first set of flow rates, and the second power output is greater than the first power output.

### Claim 252 (depends on 250)

The method of claim 250, wherein controlling in the stoichiometric control mode comprises maintaining emissions in the exhaust gas within one or more target emissions ranges while changing the flow rates from the first set of flow rates to the second set of flow rates.

### Claim 253 (depends on 248)

The method of claim 248, wherein controlling in the stoichiometric control mode comprises progressively changing the flow rates among a plurality of sets of flow rates while:
maintaining the substantially stoichiometric ratio;
progressively reducing the flow rates among the plurality of sets of flow rates;
progressively reducing a power output of the turbine among a plurality of power outputs; and
maintaining emissions in the exhaust gas within one or more target emissions ranges.

### Claim 254 (depends on 248)

The method of claim 248, comprising controlling one or more operational parameters for:
progressively changing the flow rates among a plurality of sets of flow rates;
progressively changing a power output of the turbine among a plurality of power outputs in response to changing the flow rates;
maintaining emissions in the exhaust gas within one or more target emissions ranges before and after changing the flow rates;
maintaining a temperature of the exhaust gas along the exhaust recirculation path within a target temperature range before and after changing the flow rates; and
maintaining a pressure of the exhaust gas along the exhaust recirculation path within a target pressure range before and after changing the flow rates.

### Claim 255 (depends on 248)

The method of claim 248, comprising independently controlling fluid flows through first and second fluid supply circuits, wherein the turbine combustor comprises a first set of fuel nozzles coupled to the first fluid supply circuit and a second set of fuel nozzles coupled to the second fluid supply circuit, wherein at least one of the first or second set of fuel nozzles comprises a first diffusion fuel nozzle configured to generate the diffusion flame.

### Claim 256 (depends on 248)

The method of claim 248, wherein injecting comprises separately injecting the at least one oxidant and the at least one fuel from respective first and second passages that are isolated from one another along a first diffusion fuel nozzle.

### Claim 257

A method, comprising:
introducing an oxidant to at least one oxidant compressor to produce a compressed oxidant stream;
introducing a recirculated gas stream to a compressor section of a gas turbine engine to produce a compressed recirculated gas stream;
introducing a first portion of the compressed oxidant stream with a first compressed oxidant flow rate and a fuel stream with a first fuel flow rate in a substantially stoichiometric ratio to at least one turbine combustor;
mixing the compressed oxidant stream and the fuel stream at the point of combustion and combusting the mixture of the compressed oxidant stream and the fuel stream;
introducing a first portion of the compressed recirculated gas stream with a compressed recirculated gas flow rate to the at least one turbine combustor and mixing it with the combusting streams of compressed oxidant and fuel after the point of combustion to produce a combustion products stream;
introducing the combustion products stream to an expander section of the gas turbine engine and expanding the combustion products stream to produce a first mechanical power and an exhaust gas stream at a first exhaust gas flow rate and a first emissions level;
using a first portion of the first mechanical power to drive the compressor section of the gas turbine engine;
using a second portion of the first mechanical power to drive at least one of: a generator, the at least one oxidant compressor, or at least one other mechanical device;
recirculating the exhaust gas stream in a recirculation loop from an outlet of the expander section to an inlet of the compressor section of the gas turbine engine to produce the recirculated gas stream;
extracting at least a second portion of the compressed recirculated gas stream from the gas turbine engine and delivering the at least a second portion of the compressed recirculated gas stream to a first oxidation catalyst unit to produce a first product stream having a second emissions level that is lower than the first emissions level;
reducing the first fuel flow rate and the first compressed oxidant flow rate to a second fuel flow rate and a second compressed oxidant flow rate, respectively, while maintaining the substantially stoichiometric ratio, to produce a second mechanical power that is less than the first mechanical power and a second product stream having a third emissions level that is within a target range;
reducing the second fuel flow rate and the second compressed oxidant flow rate to a third fuel flow rate and a third compressed oxidant flow rate, respectively, while maintaining the substantially stoichiometric ratio, to produce a third mechanical power that is less than the second mechanical power and a third product stream having a fourth emissions level that is at a limit of a target range; and
reducing the third fuel flow rate and the third compressed oxidant flow rate to a fourth fuel flow rate and a fourth compressed oxidant flow rate, respectively, such that fuel lean combustion occurs, to produce a fourth mechanical power that is less than the third mechanical power and a fourth product stream having a fifth emissions level that is higher than the target range.