# US 2009/0260368 A1 · Method for operating a gas turbine

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- Number: US 2009/0260368 A1
- Document ID: US20090260368A1
- Status: Published application
- Kind: A1
- Application number: 12/471,665
- Filed: 2009-05-26
- Published: 2009-10-22
- Earliest claimed: 2006-12-01
- Assignees: ALSTOM Technology Ltd
- Inventors: Eribert Benz; Peter Flohr; Adnan Eroglu; Felix Guethe; Jaan Hellat
- Web page: https://patentgrep.com/patent/US20090260368A1

## CPC

- F02C 6/003: {Gas-turbine plants with heaters between turbine stages}
- C10J 3/00: Production of combustible gases containing carbon monoxide from solid carbonaceous fuels (destructive distillation processes C10B)
- F02C 3/28: using a separate gas producer for gasifying the fuel before combustion
- F25J 3/04545: {for the gasification of solid or heavy liquid fuels, e.g. integrated gasification combined cycle [IGCC]}
- F25J 3/04575: {for a gas expansion plant, e.g. dilution of the combustion gas in a gas turbine}
- C10J 2300/093: Coal
- C10J 2300/0959: Oxygen
- C10J 2300/1606: Combustion processes
- C10J 2300/165: integrated with a gas turbine or gas motor
- C10J 2300/1671: with the production of electricity
- C10J 2300/1675: making use of a steam turbine
- C10J 2300/1678: with air separation
- C10J 2300/1892: with one stream being water/steam
- Y02E 20/16: Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
- Y02E 20/18: Integrated gasification combined cycle [IGCC], e.g. combined with carbon capture and storage [CCS]
- 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)
- C10J: PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES (synthesis gas from liquid or gaseous hydrocarbons C01B; underground gasification of minerals E21B43/295); CARBURETTING AIR OR OTHER GASES
- F25J: LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)}
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method for operating a gas turbine (11), which is used especially in a combined-cycle power plant (30), includes inducting and compressing air by the gas turbine (11), the compressed air is fed to a combustor (18, 19) for the combustion of a syngas which is produced from coal, and the hot gases which result during the combustion are expanded in a subsequent turbine (16, 17), performing work, wherein some of the compressed air is separated into oxygen and nitrogen, and the oxygen is used in a coal gasification plant (34) for producing the syngas. With such a method, a reduction of the NOx emission is achieved without noticeable loss of output and flexibility of operation by a gas turbine (11) with reheating being used, which includes two combustors (18, 19) and two turbines (16, 17), wherein in the first combustor (18) syngas is combusted, using the compressed air, and the resulting hot gases are expanded in the first turbine (16), and wherein in the second combustor syngas is combusted, using the gases which issue from the first turbine (16), and the resulting hot gases are expanded in the second turbine (17), the two combustors (18, 19) are operated with undiluted syngas, and the flame temperature (TF) in the first combustor (18) of the gas turbine (11) is lowered compared with the operation with natural gas (TNG), while the second combustor (19) is operated largely in the normal operation (TNG) which is designed for natural gas.

## Claims

### Claim 1

A method for operating a gas turbine, in which method air is inducted and compressed by the gas turbine, the compressed air is fed to a combustor for combustion of a syngas which is produced from coal, and the hot gases resulting from combustion are expanded in a subsequent turbine, performing work, wherein some of the compressed air is separated into oxygen and nitrogen, and the oxygen is used in a coal gasification plant for producing the syngas, the method comprising:
providing a reheating gas turbine which comprises two combustors and two turbines;
combusting undiluted syngas in the first combustor with the compressed air to produce first hot gases;
expanding said first hot gases in the first turbine;
combusting undiluted syngas in the second combustor with gases which issue from the first turbine, to produce second hot gases;
expanding said second hot gases in the second turbine;
maintaining the flame temperature (TF) in the first combustor lower as compared with operation of the first combustor with natural gas (TNG), and maintaining the flame temperature in the second combustor at a normal temperature (TNG) for natural gas.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein said syngas comprises CO-rich syngas, and wherein maintaining the flame temperature (TF) in the first combustor comprises maintaining at a temperature lowered by 50-100 K compared to operation with natural gas.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein said syngas comprises H2-rich syngas, and wherein maintaining the flame temperature (TF) in the first combustor comprises maintaining at a temperature lowered by 100-150 K compared to operation with natural gas.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein said gas turbine is in a combined-cycle power plant.