Method for operating a gas turbine assembly and gas turbine assembly

Abstract

A gas turbine assembly (1) extending along a longitudinal axis (A) and comprising a compressor (2), a combustion chamber assembly (4) and at least one gas turbine (5); the compressor (2) comprising an inlet (9) to which air is supplied and an outlet (10) through which air compressed by the compressor (2) flows; the outlet (10) of the compressor (2) leads out into an air chamber (3) which is fluidically connected to the combustion chamber assembly (4); the combustion chamber assembly (4) comprises at least one combustion chamber (15) which is coupled to the gas turbine (5) and is provided with a plurality of burners (18); the gas turbine assembly (1) is provided with a control device (8) which is configured to control the pressure of the air in the air chamber (3) based on at least one parameter (P) indicative of the air pressure measured in the air chamber (3). pl ) to control the combustion chamber assembly (4).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority from European patent application no. 19220199.4 filed on December 31, 2019, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The invention relates to a method for operating a gas turbine assembly and to a gas turbine assembly. In particular, the gas turbine assembly of the invention is part of a power plant. Background Art

[0004] As is known, a gas turbine assembly for a power plant includes a compressor, a combustor, and a turbine.

[0005] In particular, the compressor comprises an inlet to which air is supplied and a plurality of rotating blades which compress the air passing therethrough. The compressed air leaving the compressor flows into a plenum (i.e. a closed volume defined by a casing) and from there into a combustion chamber. In the combustion chamber, the compressed air is mixed with at least one fuel and combusted. The resulting hot gases leave the combustion chamber and expand in a turbine. In the turbine, the hot gas expansion moves rotating blades connected to a rotor, thereby performing work.

[0006] As is known, during normal operation of a power plant, the power demand from the network may vary. When the power demand from the network is low (e.g. at night), the power plant for generating electrical energy operates at a minimum environmental load. Under said load, the gas turbine assembly produces pollutant emissions (NOx and CO) below the legal limits.

[0007] However, when a power plant is operated at a transition load including between a minimum load and a base load, pollutant emissions cannot always be controlled in a reliable and stable manner.

[0008] In particular, when the load is below the minimum environmental load (MEL) and a shut-down of the burner occurs, pollutants cannot be controlled in a reliable manner. Summary of the invention

[0009] It is therefore an object of the present invention to provide a method for operating a gas turbine assembly which enables the combustion chamber assembly to be controlled in a stable and robust manner in order to maintain pollutant emissions below legal limits under all load operations.

[0010] In particular, the object of the present invention is to provide a method for operating a gas turbine assembly, which extends along a longitudinal axis and includes a compressor, a combustion chamber assembly and at least one gas turbine; the compressor includes an inlet for supplied air and an outlet through which air compressed by the compressor flows; the outlet of the compressor is connected to an air chamber, which is fluidically connected to the combustion chamber assembly; the combustion chamber assembly includes at least one combustion chamber, which is connected to the gas turbine and is provided with a plurality of burners; the method includes controlling the combustion chamber assembly based on at least one parameter indicating the air pressure measured in the air chamber.

[0011] In this way, the control of the combustion chamber assembly is more efficient. In particular, controlling the combustion chamber assembly based on a parameter indicative of the pressure in the air chamber has great advantages in terms of reliability and stability during operation of the gas turbine assembly at any load. The pressure in the air chamber has a better correlation with the fuel mass flow rate than the commonly used parameters, especially at transient loads.

[0012] Therefore, reliable contamination control is achieved at any operating load.

[0013] According to a preferred embodiment of the invention, the step of controlling the combustion chamber assembly comprises regulating the fuel supply to at least one combustion chamber based at least on a parameter indicative of an air pressure measured in the air chamber.

[0014] According to a preferred embodiment of the invention, regulating the fuel supply to the at least one combustion chamber comprises regulating the amount of fuel supplied to the at least one combustion chamber and / or regulating the shut-off of at least one of a plurality of burners of the combustion chamber.

[0015] According to a preferred embodiment of the present invention, regulating the fuel supply to at least one combustion chamber comprises:

[0016] · calculating current carbon monoxide emissions based on at least a parameter indicative of air pressure measured in the air chamber;

[0017] Regulate the fuel supply to keep CO emissions below the CO limit.

[0018] According to a preferred embodiment of the present invention, the current carbon monoxide emissions are calculated based at least on:

[0019] · The air pressure measured in the air chamber;

[0020] · The number of burners switched on in the combustion chamber;

[0021] · The temperature at the inlet of the gas turbine.

[0022] According to a preferred embodiment of the invention, the temperature at the inlet of the gas turbine is calculated based on at least one parameter indicative of the air pressure measured in the air chamber.

[0023] According to a preferred embodiment of the present invention, regulating the fuel supply to at least one combustion chamber comprises:

[0024] · calculating a shutoff parameter based on at least a parameter indicative of air pressure measured in the air chamber;

[0025] · Regulate the fuel supply so that emissions of the shut-off parameters remain above defined limits.

[0026] Another object of the present invention is to provide a gas turbine assembly that can operate under transient loads while maintaining pollutant emissions within legal limits.

[0027] According to this object, the present invention relates to a gas turbine assembly, which extends along a longitudinal axis and comprises a compressor, a combustion chamber assembly and at least one gas turbine; the compressor comprises an inlet through which air is supplied and an outlet through which air compressed by the compressor flows; the outlet of the compressor leads out into an air chamber, which is in fluid communication with the combustion chamber assembly; the combustion chamber assembly comprises at least one combustion chamber, which is coupled to the gas turbine and is provided with a plurality of burners;

[0028] The gas turbine assembly comprises a control device configured to control the combustor assembly based on at least one parameter indicative of air pressure measured in the plenum;

[0029] wherein the control device comprises a supply control unit configured to regulate the supply of fuel to the at least one combustion chamber based at least on a parameter indicative of an air pressure measured in the air chamber;

[0030] wherein the control device comprises a CO unit configured to calculate current carbon monoxide emissions based at least on a parameter indicative of the air pressure measured in the air chamber and at least one of the following parameters:

[0031] - hot gas pressure at the exhaust of the gas turbine;

[0032] - the temperature at the inlet of the compressor;

[0033] - the number of burners switched on in the combustion chamber;

[0034] - the temperature at the inlet of the gas turbine;

[0035] The supply control unit is configured to regulate the fuel supply so that CO emissions are kept below a CO limit; wherein current carbon monoxide emissions are calculated based on an air pressure measured in the air chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention will now be described with reference to the accompanying drawings showing some non-limiting embodiments, in which:

[0037] - Figure 1 is a schematic diagram of a gas turbine assembly according to the present invention;

[0038] - Figure 2 It involves Figure 1 A block diagram of the details of the components;

[0039] - Figure 3 is a graph relating to the behavior of the pressure in the internal plenum during transient loads and the temperature at the exhaust port of the gas turbine. DETAILED DESCRIPTION

[0040] exist Figure 1 , reference numeral 1 indicates a schematically represented gas turbine assembly.

[0041] The gas turbine assembly 1 comprises a compressor 2, a plenum 3, a combustor assembly 4, a turbine 5, a fuel supply assembly 6 and a control device 8. The compressor 2 and the turbine 5 extend along a main axis A.

[0042] The compressor 2 comprises an inlet 9 for supplied air and an outlet 10 through which the air compressed by the compressor 2 flows; the outlet 10 of the compressor 2 leads out into the air chamber 3 which is in fluid communication with the combustion chamber assembly 4 .

[0043] The fuel supply assembly 6 supplies at least one fuel to the combustion chamber assembly 4. In the combustion chamber assembly 4, the compressed air from the air chamber 3 is mixed with the fuel and combusted.

[0044] The combusted mixture then expands in the turbine 5 and is converted into mechanical power via a shaft 12 which is connected to an alternator (not shown).

[0045] In the non-limiting example disclosed and shown herein, the combustion chamber assembly 4 is a sequential combustion chamber assembly, which includes a first-stage combustion chamber 14 and a second-stage combustion chamber 15 sequentially arranged along the gas flow direction G. In other words, the second-stage combustion chamber 15 is arranged downstream of the first-stage combustion chamber 14 along the gas flow direction G.

[0046] Preferably, a mixer 16 is arranged between the first-stage combustion chamber 14 and the second-stage combustion chamber 15 .

[0047] The second stage combustion chamber 15 includes a plurality of burners 18 , which are preferably arranged circumferentially.

[0048] According to a variant that is not shown, the first combustion chamber also comprises a plurality of burners.

[0049] According to a variant of the invention that is not shown, the sequential combustion chamber may comprise a high-pressure turbine between the first-stage combustion chamber and the second-stage combustion chamber instead of a mixer.

[0050] According to a variant that is not shown, the combustion chamber assembly is not sequential and comprises only one combustion chamber provided with a plurality of burners.

[0051] In the non-limiting example disclosed and illustrated herein, the fuel supply assembly 6 supplies at least one fuel to the first stage combustion chamber 14 and the second stage combustion chamber 15, and the fuel supply assembly includes an actuator assembly 19 (schematically represented) configured to adjust the amount of fuel supplied to the first stage combustion chamber 14 and the second stage combustion chamber 15 under the control of the control device 8.

[0052] In the non-limiting example disclosed and illustrated herein, the fuel supplied to the first stage combustor 14 and the fuel supplied to the second stage combustor 15 are the same.

[0053] The air supplied to the first-stage combustion chamber 14 and the second-stage combustion chamber 15 comes from the air chamber 3 .

[0054] The amount of air in the air chamber 3 depends on the amount of air m entering the compressor 2 air The amount of air entering compressor 2 is m air This may be varied by modifying the position of inlet guide vanes (not shown) at the inlet 9 of the compressor 3 .

[0055] The control device 8 is configured to control the combustion chamber assembly 4 .

[0056] In particular, the control device 8 is configured to indicate the air pressure P measured in the air chamber 3 based on pl at least one parameter of the combustion chamber component 4 is used to control the combustion chamber component 4.

[0057] The gas turbine assembly 1 comprises at least one pressure sensor 20, which is configured to detect the air pressure P in the air chamber 3. pl The value of .

[0058] In the non-limiting example disclosed and shown here, the air chamber 3 is provided with at least one pressure measuring interface (not shown), which is connected to a corresponding pressure sensor 20 (in Figure 1 are associated with each other (schematically represented by boxes in the figure).

[0059] Preferably, the pressure measuring interface is a hole made in the wall of the air chamber 3, which is used to connect the pressure sensor 20 to the air chamber 3 to measure the static pressure.

[0060] In more detail, the control device 8 is configured to indicate the air pressure P measured in the air chamber 3 based on pl at least one parameter of the combustion chamber component 4 is used to control the combustion chamber component 4.

[0061] refer to Figure 2 , the control device 8 includes a CO unit 21 , a BSP unit 22 and a supply control unit 24 .

[0062] The CO unit 21 is configured to indicate the air pressure P measured in the air chamber 3 based on the indication. pl at least one parameter of the current CO emissions (carbon monoxide emissions).

[0063] Preferably, the CO unit 21 is configured to generate a pressure signal based on the air pressure P measured in the air chamber 3. pl The current CO emissions are calculated based on at least one of the following parameters:

[0064] - Hot gas pressure P at the exhaust port 26 of the gas turbine 5 ex ;

[0065] - The number n of burners 18 switched on in the second stage combustion chamber 15 ON ;

[0066] - Temperature T at the inlet of the gas turbine 5 HG ;

[0067] - Temperature T at the inlet 9 of the compressor 2 k1 .

[0068] Preferably, at least based on the air pressure P measured in the air chamber 3 pl To calculate the temperature T at the inlet 25 of the turbine 5 HG .

[0069] More preferably, based on the air pressure P measured in the air chamber 3 pl The temperature T at the inlet 25 of the turbine 5 is calculated based on at least one of the following parameters: HG :

[0070] - Air volume m entering compressor 2 air ;

[0071] - The amount of fuel m supplied to the second stage combustion chamber 15 fuel ;

[0072] - Hot gas pressure P at the exhaust port 26 of the gas turbine 5 ex .

[0073] The BSP unit 22 is configured to determine the air pressure P measured in the air chamber 3 based on at least pl To calculate the shutdown parameter BSP.

[0074] Preferably, based on the air pressure P measured in the air chamber 3 pl And calculate the BSP parameters based on at least one of the following parameters:

[0075] - Average temperature TAT at the exhaust port 26 of the turbine 5 avg ;

[0076] - Hot gas pressure P at the exhaust port 26 of the gas turbine 5 ex ;

[0077] - Temperature T at the inlet 9 of the compressor 2 k1；

[0078] - Gas composition of fuel C 2+ ;

[0079] - The fuel temperature T measured upstream of the combustion chamber assembly 4 fuel .

[0080] The supply control unit 24 is configured to regulate the shutoff of the plurality of burners 18 and the fuel supply to the combustion chamber assembly 4 based on the shutoff parameter BSP calculated by the BSP unit 22 and / or based on the current CO emissions calculated by the CO unit 21 .

[0081] The supply control unit 24 is configured to regulate the shut-off of the plurality of burners 18 and the fuel supply to the combustion chamber assembly 4 such that the shut-off parameter BSP is above a certain BSP limit and / or such that current CO emissions do not exceed a CO limit value.

[0082] In other words, the supply control unit 24 is configured to determine the number n of burners 18 that are switched on. ON and the amount of fuel m to be supplied to the combustion chamber assembly 4 fuel .

[0083] In use, the gas turbine assembly 1 is operated at different loads depending on the requirements of the network.

[0084] Under any load, the control device 8 regulates the combustion chamber assembly 4 so that by adjusting the number n of burners 18 switched on in the second stage combustion chamber 15 ON and / or the amount of fuel m to be supplied to the combustion chamber assembly 4 fuel To keep pollutant emissions below limits.

[0085] Using a parameter indicative of the pressure in the gas chamber for controlling the combustor assembly 4 has great advantages in terms of reliability and stability during operation of the gas turbine assembly 1 .

[0086] look Figure 3 The graph in Figure 2 shows the pressure P in chamber 3 (dashed line) compared to the turbine exhaust temperature (full extended line) under transient load. pl The correlation with fuel mass flow is better.

[0087] Therefore, the pressure P in the gas chamber 3 is used in the control of the combustion chamber assembly 4. pl A more reliable operation of the gas turbine assembly 1 will result.

[0088] Finally, it is evident that modifications and variations may be made to the methods and components described herein without departing from the scope of the present invention as defined in the appended claims.

Claims

1. A method for operating a gas turbine assembly (1), the gas turbine assembly (1) extending along a longitudinal axis (A) and comprising a compressor (2), a combustion chamber assembly (4) and at least one gas turbine (5); the compressor (2) comprising an inlet (9) to which air is supplied and an outlet (10) through which air compressed by the compressor (2) flows; the outlet (10) of the compressor (2) leads out into an air chamber (3), the air chamber (3) being in fluid communication with the combustion chamber assembly (4); the combustion chamber assembly (4) comprising at least one combustion chamber (15), the at least one combustion chamber (15) being coupled to the gas turbine (5) and being provided with a plurality of burners (18); The method comprises: based on an indication of the air pressure (P) measured in the air chamber (3) pl ) to control the combustion chamber component (4); The step of controlling the combustion chamber assembly (4) comprises at least one step of controlling the combustion chamber assembly (4) based on an indication of the air pressure (P) measured in the air chamber (3) pl ) parameters to adjust the fuel supply to the at least one combustion chamber (15); Wherein regulating the fuel supply to the at least one combustion chamber (15) comprises: Based on the air pressure (P pl ) and at least one of the following parameters to calculate the current carbon monoxide (CO) emissions: - the hot gas pressure (P) at the exhaust port (26) of the gas turbine (5) ex ); - The temperature (T) at the inlet (9) of the compressor (2) k1 ); - The number (n) of burners (18) switched on in the combustion chamber (15) ON ); - the temperature (T HG ); The fuel supply is regulated to keep CO emissions below a CO limit.

2. The method according to claim 1, characterized in that Regulating the fuel supply to the at least one combustion chamber (15) comprises regulating the amount of fuel supplied to the at least one combustion chamber (15) and / or regulating the shutoff of at least one of the plurality of burners (18) of the combustion chamber (15).

3. The method according to claim 2, characterized in that At least based on an indication of the air pressure (P pl ) is used to calculate the temperature (T) at the inlet (25) of the gas turbine (5). HG ).

4. The method according to claim 3, characterized in that: Based on the air pressure (P pl ) and calculating the temperature (T) at the inlet (25) of the gas turbine (5) based on at least one of the following parameters: HG ): - The amount of air entering the compressor (2) (m air ); - The amount of fuel supplied to the combustion chamber (15) (m fuel ); - the hot gas pressure (P) at the exhaust port (26) of the gas turbine (5) ex ).

5. A gas turbine assembly (1), the gas turbine assembly extending along a longitudinal axis (A) and comprising a compressor (2), a combustion chamber assembly (4) and at least one gas turbine (5); the compressor (2) comprising an inlet (9) to which air is supplied and an outlet (10) through which air compressed by the compressor (2) flows; the outlet (10) of the compressor (2) leads out into an air chamber (3), the air chamber (3) being fluidically connected to the combustion chamber assembly (4); the combustion chamber assembly (4) comprising at least one combustion chamber (15), the at least one combustion chamber (15) being coupled to the gas turbine (5) and being provided with a plurality of burners (18); The gas turbine assembly (1) comprises a control device (8) configured to indicate, based on an indication of an air pressure (P pl ) to control the combustion chamber component (4); The control device (8) comprises a supply control unit (24) configured to control the air pressure (P) measured in the air chamber (3) based on at least one indication of the air pressure (P pl ) parameters to adjust the fuel supply to the at least one combustion chamber (15); The control device (8) comprises a CO unit (21) configured to indicate at least based on an air pressure (P pl ) and at least one of the following parameters to calculate the current carbon monoxide (CO) emissions: - the hot gas pressure (P) at the exhaust port (26) of the gas turbine (5) ex ); - The temperature (T) at the inlet (9) of the compressor (2) k1 ); - The number (n) of burners (18) switched on in the combustion chamber (15) ON ); - the temperature (T HG ); The supply control unit (24) is configured to regulate the fuel supply so that CO emissions remain below a CO limit; Based on the air pressure (P pl ) to calculate current carbon monoxide (CO) emissions.

6. The gas turbine assembly according to claim 5, characterized in that The supply control unit (24) is configured to regulate the amount of fuel supplied to the at least one combustion chamber (15) and / or to regulate the shutoff of at least one of the plurality of burners (18) of the combustion chamber (15).

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