# US 10,865,710 B2 · Preparation of exhaust gas from a gas turbine for exhaust gas recirculation

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- Number: US 10,865,710 B2
- Document ID: US10865710B2
- Status: Granted
- Kind: B2
- Application number: 14/477,246
- Filed: 2014-09-04
- Published: 2014-12-18
- Granted: 2020-12-15
- Earliest claimed: 2012-03-05
- Assignees: General Electric Technology GmbH
- Applicants: General Electric Technology GmbH
- Inventors: Wuyin Wang; Richard Joel Curran; Frank Sander; Klara Berg; Richard Carroni; Gian Luigi Agostinelli
- Web page: https://patentgrep.com/patent/US10865710B2

## 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
- B01D 53/96: Regeneration, reactivation or recycling of reactants
- F01N 3/085: {Sulfur or sulfur oxides}
- F23J 15/04: using washing fluids {(scrubbers for removing solids only F23J15/022)}
- F01K 23/10: with exhaust fluid of one cycle heating the fluid in another cycle (F01K17/025 takes precedence)
- F01N 3/0885: {Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps}
- 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 7/141: of working fluid
- F05D 2260/213: by the provision of a heat exchanger within the cooling circuit
- F05D 2270/08: to produce clean exhaust gases
- F23J 2219/40: Sorption with wet devices, e.g. scrubbers
- Y02E 20/16: Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
- 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)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- F23J: REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES (combustion apparatus for consuming smoke or fumes, e.g. exhaust gases, F23G7/06)
- 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
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method of operating a turbine unit, wherein recirculated exhaust gas is contacted with a cooling and absorption liquid in a packed bed. An exhaust gas treatment system for a turbine unit, wherein an exhaust gas recirculation line comprises a gas cooling and cleaning device having a packed bed for contacting the exhaust gas with a cooling and absorption liquid. A combined cycle power generating system, wherein an exhaust gas recirculation line comprises a gas cooling and cleaning device having a packed bed for contacting the exhaust gas from a gas turbine with a cooling and absorption liquid and wherein water utilized as a cooling medium for condensation of steam originating from a steam turbine, and the cooling and absorption liquid, are passed to a cooling tower.

## Claims

### Claim 1

A method of operating a turbine unit having a compressor for compression of inlet air, a combustor for combustion of a fuel with the compressed inlet air to form an exhaust gas, and a turbine for expansion of the exhaust gas, comprising recirculating at least a first portion of the exhaust gas originating from the turbine and mixing the recirculated exhaust gas with ambient air before feeding the mixture as inlet air to the compressor,
wherein the recirculated exhaust gas is contacted with a first cooling and absorption liquid in a counter current flow in a first packed bed of a first gas cooling and cleaning device to perform cooling and absorption of the recirculated exhaust gas in the first packed bed, to lower a temperature of the recirculated exhaust gas from between about 80° C. to about 120° C. to between about 10° C. to about 50° C. within the first packed bed and to remove contaminants from the recirculated exhaust gas; and
wherein an S03 binding reagent is added to the exhaust gas originating from the turbine before the recirculated exhaust gas is contacted with the first cooling and absorption liquid,
wherein the method further includes:
feeding a primary supply of cooling water to a cooling tower for condensation of steam from a steam turbine;
feeding at least a portion of the first cooling and absorption liquid that has been contacted with the recirculated exhaust gas to the cooling tower as make-up water to supplement the primary supply of cooling water;
measuring a pH of the first cooling and absorption liquid after exiting the cooling tower and prior to returning the cooled first cooling and absorption liquid to the first gas cooling and cleaning device; and
adding a substance to the first cooling and absorption liquid in dependence upon the measurement to adjust the pH of the first cooling and absorption liquid prior to returning the cooled first cooling and absorption liquid to the first gas cooling and cleaning device.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the SO3 binding-reagent is added in the form of a substantially homogeneous solution.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the recirculated exhaust gas after having been contacted with the first cooling and absorption liquid has
a total level of SO2 and SO3 lower than or equal to about 150 ppbv, and/or
a total level of Na and K lower than or equal to 5 ppbv.

### Claim 4 (depends on 1)

The method according to claim 1, wherein a second portion of the exhaust gas originating from the turbine is contacted with a second cooling and absorption liquid in a second packed bed, so that a temperature of the second portion of the exhaust gas is lowered and contaminants are removed from the second portion of the exhaust gas, and is subsequently subjected to removal of CO2.

### Claim 5 (depends on 1)

The method according to claim 1, wherein a portion of the recirculated exhaust gas having been contacted with the first cooling and absorption liquid is subsequently subjected to removal of CO2.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the recirculated exhaust gas has
a level of SO2 of from about 0.5 ppmv to about 5 ppmv, and/or
a level of SO3 of from about 0.5 ppmv to about 5 ppmv.

### Claim 7

A combined cycle power generating system comprising:
a gas turbine unit having a compressor for compression of inlet air, a combustor for combustion of a fuel with the compressed inlet air to form an exhaust gas, and a gas turbine for expansion of the exhaust gas;
a steam generator utilizing heat of the exhaust gas originating from the gas turbine for generation of steam;
a steam turbine for expansion of the steam generated by the steam generator;
a condenser utilizing water as a cooling medium for condensation of the steam originating from the steam turbine;
a first cooling circuit for cooling of said water utilized as the cooling medium by the condenser and returning said water to the condenser, the first cooling circuit comprising a cooling tower for removal of heat from said water; and
a recirculation line for passing at least a first portion of the exhaust gas originating from the gas turbine to the compressor;
wherein the recirculation line comprises a first gas cooling and cleaning device having a first packed bed for contacting the first portion of the exhaust gas with a first cooling and absorption liquid in a counter current flow to perform cooling and absorption of the first portion of the recirculated exhaust gas in the first packed bed, to lower a temperature of the first portion of the exhaust gas and to remove contaminants from the first portion of the exhaust gas,
wherein the system further comprises a second cooling circuit for cooling of the first cooling and absorption liquid utilized by the first gas cooling and cleaning device and returning it to the first gas cooling and cleaning device, the second cooling circuit comprising said cooling tower of the first cooling circuit for removal of heat from said first cooling and absorption liquid;
wherein the system further comprising a pH control system configured to measure a pH of the first cooling and absorption liquid after exiting the cooling tower and prior to returning the cooled first cooling and absorption liquid to the first gas cooling and cleaning device, and to add a substance to the first cooling and absorption liquid to adjust the pH of the first cooling and absorption liquid in dependence upon the measurement prior to returning the cooled first cooling and absorption liquid to the first gas cooling and cleaning device;
wherein the recirculation line is provided with a reagent injector located upstream of the first gas cooling and cleaning device;
wherein the first cooling circuit and the second cooling circuit are in fluid communication with one another within the cooling tower such that acidity of the first cooling and absorption liquid reduces scaling resulting from alkalinity of the water utilized as the cooling medium.

### Claim 8 (depends on 7)

The combined cycle power generating system according to claim 7, further comprising a line for passing a second portion of the exhaust gas originating from the gas turbine to a CO2 capture unit, the line comprising a second gas cooling and cleaning device having a second packed bed for contacting the second portion of the exhaust gas with a second cooling and absorption liquid.

### Claim 9 (depends on 7)

The combined cycle power generating system according to claim 7, wherein the recirculation line is connected, downstream of the first gas cooling and cleaning device, with a line for passing the first portion of the exhaust gas to a CO2 capture unit.

### Claim 10

An exhaust gas treatment system comprising:
a turbine unit having a compressor for compression of inlet air, a combustor for combustion of a fuel with the compressed inlet air to form an exhaust gas, and a turbine for expansion of the exhaust gas;
a recirculation line for passing at least a first portion of the exhaust gas originating from the turbine to the compressor, the recirculation line comprising a first gas cooling and cleaning device having a first packed bed for contacting the first portion of the exhaust gas with a first cooling and absorption liquid in a counter current flow to perform cooling and absorption of the recirculated exhaust gas in the first packed bed, to lower a temperature of the recirculated exhaust gas and to remove contaminants from the recirculated exhaust gas;
a cooling circuit for cooling of the first cooling and absorption liquid utilized by the first gas cooling and cleaning device, and returning the first cooling and absorption liquid to the first gas cooling and cleaning device, the cooling circuit comprising a cooling tower that receives a primary supply of cooling water for condensation of steam from a steam turbine, and receives at least a portion of the first cooling and absorption liquid for removal of heat from said first cooling and absorption liquid; and
a pH control system configured to measure a pH of the first cooling and absorption liquid after exiting the cooling tower and prior to returning the cooled first cooling and absorption liquid to the first gas cooling and cleaning device, and to add a substance to the first cooling and absorption liquid to adjust the pH of the first cooling and absorption liquid prior to returning the cooled first cooling and absorption liquid to the first gas cooling and cleaning device in dependence upon the measurement;
wherein the recirculation line is provided with a reagent injector located upstream of the first gas cooling and cleaning device.

### Claim 11 (depends on 10)

The exhaust gas treatment system according to claim 10, further comprising a line for passing a second portion of the exhaust gas originating from the turbine to a CO2 capture unit, the line comprising a second gas cooling and cleaning device having a second packed bed for contacting the exhaust gas with a second cooling and absorption liquid.

### Claim 12 (depends on 10)

The exhaust gas treatment system according to claim 10, wherein the recirculation line is connected, downstream of the first gas cooling and cleaning device, with a line for passing a portion of the exhaust gas to a CO2 capture unit.