Method for operating a gas turbine and a gas turbine for implementing the method
View Patent ↗In a method for operating a gas turbine ( 11 ) in a combined cycle power plant ( 40 ), air is drawn in and compressed though the gas turbine ( 11 ), the compressed air is led to a combustor ( 18, 19 ) to burn a syngas recovered from a fossil fuel, especially coal, and the gases that result in the course of the combustion are expanded in a downstream turbine ( 16, 17 ). In such a method, an improved degree of efficiency is achieved by virtue of the fact that a gas turbine ( 11 ) with reheating is used, which includes two combustors ( 18, 19 ) and two turbines ( 16, 17 ); in the first combustor ( 18 ), syngas is burned with the compressed air, and the resultant hot gases, e.g., flue gases, are expanded in the first turbine ( 16 ), and in the second combustor syngas is burned by the gases coming from the first turbine ( 16 ), and the resultant hot gases are expanded in the second turbine ( 17 ).
1. A method for operating a gas turbine, the method comprising:
drawing in and compressing air with the gas turbine;
conducting compressed air to a combustion chamber;
combusting a syngas that is generated from a fossil fuel with said compressed air, to generate hot gases;
expanding the combustion hot gases in a downstream turbine;
separating a portion of the compressed air into oxygen and nitrogen;
using separated oxygen in a fossil fuel gasifier to produce the syngas;
using a portion of the compressed air to cool parts of the gas turbine that are exposed to hot gases;
wherein said gas turbine comprises a gas turbine with reheating including two combustors and two turbines, such that in a first of said two combustors, said syngas is combusted using the compressed air and the resultant hot gases are expanded in a first of said two turbines, and such that in a second of said two combustors, said syngas is combusted using gases from said first turbine and the resultant hot gases are expanded in a second of said two turbines;
diluting, with 80-100% of the separated nitrogen, the syngas that is combusted in the second combustor; and
diluting the syngas that is combusted in the first combustor with the remaining portion of the separated nitrogen.
2. A method according to claim 1 , further comprising:
directly blowing the nitrogen that occurs in conjunction with the separation of the air into the second combustor.
3. A method according to claim 1 , further comprising:
compressing to a higher pressure in a compressor the nitrogen provided for the first combustor, prior to being blown into the combustor.
4. A method according to claim 1 , further comprising:
blowing into the second combustor a portion of the syngas produced in the coal gasifier without further compression.
5. A method according to claim 1 , further comprising:
compressing a portion of the syngas produced in the coal gasifier to a higher pressure in a compressor; and
thereafter blowing said compressed portion of the syngas into the first combustor.
6. A method according to claim 1 , further comprising:
blowing into the combustors the syngas and the diluting nitrogen in a concentric arrangement, such that a nitrogen jet surrounds a syngas jet in the form of a mantle, in a direction perpendicular to the direction of inflowing compressed air, which compressed air flows into the combustors, or of outgoing air from the first turbine.
7. A method according to claim 1 , wherein the gas turbine is part of a combined cycle power plant.
8. A method according to claim 1 , wherein said fossil fuel comprises coal.