System and method for extended emissions compliant operation of a gas turbine engine

Abstract

The present invention is entitled "System and method for extended emissions compliance operation of a gas turbine engine". The present invention discloses a method (200) for operating a rotary machine (100) in a responsive mode (306) below a minimum emissions compliance load (302) including reducing (206) a fuel split to zero. The fuel split distributes a total fuel flow to a combustor (106) between a first combustion zone (115) and a second combustion zone (117). The method (200) also includes determining a current operating temperature of the first combustion zone (115) using a digital simulation of the rotary machine (100). The method (200) also includes determining a target operating temperature of the first combustion zone (115). The target operating temperature enables the rotary machine (100) to operate below a conventional minimum emissions compliance load (MECL) (302) while still complying with emissions standards. The method (200) also includes directing a first fuel flow to the first combustion zone (115). The first fuel flow reduces the temperature of the first combustion zone (115) to the target operating temperature.

Description

Background Art

[0001] The technical field of the present disclosure relates generally to control of gas turbine engines and, more particularly, to control of extended emissions compliance loads of gas turbine engines.

[0002] The energy extracted from the airflow of the turbine is used to power the mechanical load of at least some known rotary machines. Specifically, the rotary machine includes a compressor section, a combustor section, and a turbine section arranged in series. The compressor section compresses air to burn with fuel in the combustor section, and the turbine section extracts energy from the combustion gases produced in the combustor section. At least some known combustor sections include axial fuel staging (AFS) technology (including axial (sequential) combustion staging in at least two regions). More specifically, the combustor section may include a plurality of first-stage fuel nozzles located upstream of a plurality of second-stage fuel nozzles. The first fuel flow is directed into the combustor by the first-stage fuel nozzle, and the second fuel flow is directed into the combustor by the second-stage fuel nozzle. The temperature in the combustor of the combustion gases produced by the combustion of the first fuel flow is T 3.5 Temperature. Control T 3.5 The temperature and air from the compressor section allow operators to control the emissions produced by rotating machinery. More specifically, carbon monoxide emissions produced by rotating machinery are typically controlled by controlling T 3.5 Temperature to control.

[0003] In addition, rotating machinery typically has a minimum emissions compliance load (MECL), which is the lowest load on the rotating machinery at which the rotating machinery can operate while still meeting emissions standards. More specifically, the traditional MECL is the lowest load on the rotating machinery at which the burner temperature helps maintain compliance with emissions standards. When the grid operating company requests the operator of the rotating machinery to reduce the operation of the rotating machinery so that the rotating machinery operates below the MECL, the operator of the rotating machinery shuts down the rotating machinery to maintain compliance with emissions standards. Therefore, rotating machinery with a higher MECL is more likely to cause operating shutdowns than rotating machinery with a lower MECL, resulting in revenue losses for operators of rotating machinery with high MECLs. Summary of the invention

[0004] In one aspect, a method for operating a rotating machine in a responsive mode at a load below a minimum emissions compliance load is provided. The rotating machine includes a burner including a first combustion zone and a second combustion zone. The method includes: i) reducing a fuel split to zero. The fuel split distributes a total fuel flow to the burner between the first combustion zone and the second combustion zone. The method also includes: ii) determining a current operating temperature of the first combustion zone using a digital simulation of the rotating machine. The method also includes: iii) determining a target operating temperature of the first combustion zone. The target operating temperature enables the rotating machine to operate at a load below a conventional minimum emissions compliance load (MECL) while still meeting emission standards. The method also includes: iv) directing a first fuel flow to the first combustion zone. The first fuel flow reduces the temperature of the first combustion zone to a target operating temperature. The method also includes: v) repeating steps i to iv until the rotating machine operates at a load below a conventional MECL and meets emission standards.

[0005] On the other hand, a method for operating a rotating machine in a standby mode at a load below a minimum emission compliance load is provided. The rotating machine includes a burner including a first combustion zone and a second combustion zone. The method includes: i) reducing a fuel split to zero. The fuel split distributes a total fuel flow to the burner between the first combustion zone and the second combustion zone. The method also includes: ii) determining a current operating temperature of the first combustion zone using a digital simulation of the rotating machine. The method also includes: iii) determining a target operating temperature of the first combustion zone. The target operating temperature enables the rotating machine to operate at a load below a conventional minimum emission compliance load (MECL) while still complying with emission standards. The method also includes: iii) determining a target operating temperature of the first combustion zone. The target operating temperature enables the rotating machine to operate at a load below a conventional minimum emission compliance load (MECL) while still complying with emission standards. The method also includes: iv) directing a first fuel flow to the first combustion zone. The first fuel flow reduces the temperature of the first combustion zone to the target operating temperature and reduces the temperature of the exhaust gas from the rotating machine to below the minimum exhaust temperature of the power plant operation. The method further comprises: v) repeating steps i to iv until the rotating machinery operates below the conventional MECL and complies with emission standards.

[0006] On the other hand, a rotary machine is provided. The rotary machine includes a compressor configured to compress an inlet air flow, a burner and a computing device. The burner includes a first combustion zone, a second combustion zone, at least one first fuel nozzle and at least one second fuel nozzle. At least one first fuel nozzle is configured to guide a first fuel flow to the first combustion zone, and at least one second fuel nozzle is configured to guide a second fuel flow to the second combustion zone. The burner is configured to receive an inlet air flow. The fuel split is a fraction of the total fuel flow directed to the second combustion zone. The computing device includes a digital simulation of the rotary machine and is configured to operate the rotary machine in a responsive mode. The computing device is configured to reduce the fuel split to zero and determine the current operating temperature of the first combustion zone using the digital simulation of the rotary machine. The computing device is also configured to determine a target operating temperature of the first combustion zone. The target operating temperature enables the rotary machine to operate at a lower level than the conventional minimum emission compliance load (MECL) while still meeting emission standards. The computing device is also configured to guide the first fuel flow to the first combustion zone. The first fuel flow reduces the temperature of the first combustion zone to the target operating temperature. The computing device is further configured to repeat until the rotating machinery operates below the conventional MECL and complies with emission standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters refer to like parts throughout the several views, and in which:

[0008] Figure 1 is a schematic diagram of an exemplary rotating machine;

[0009] Figure 2A It is used in situations where the traditional MECL Figure 1 A flow chart of an exemplary method for emissions compliant operation of a rotating machine is shown;

[0010] Figure 2B yes Figure 2A Continuation of the flowchart of;

[0011] Figure 2C yes Figure 2A and Figure 2B Continuation of the flowchart of;

[0012] Figure 2D yes Figure 2A , Figure 2B and Figure 2C Continuation of the flowchart of;

[0013] Figure 3 yes Figure 1An exemplary relationship diagram between exhaust temperature and electrical load of a rotating machine is shown.

[0014] Unless otherwise indicated, the drawings provided herein are intended to illustrate features of the embodiments of the present disclosure. It is believed that these features are applicable to a variety of systems including one or more embodiments of the present disclosure. Therefore, the drawings are not intended to include all conventional features required for practicing the embodiments disclosed herein known to those of ordinary skill in the art. DETAILED DESCRIPTION

[0015] In the following specification and claims, reference will be made to a number of terms which shall be defined to have the following meanings.

[0016] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0017] Unless otherwise indicated, approximate language as used herein, such as "substantially", "substantially" and "about" indicate that as those of ordinary skill in the art will recognize, the terms so modified may only apply to approximate degrees, rather than absolute or perfect degrees. Therefore, the value modified by one or more terms (such as "about", "approximately" and "substantially") is not limited to the specified exact value. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. Here and throughout the specification and claims, range restrictions can be identified. Unless otherwise indicated by the context or language, these ranges can be combined and / or interchanged, and include all sub-ranges contained therein. In addition, unless otherwise indicated, the terms "first", "second", etc. are only used as marks in this article, and are not intended to impose order, position or hierarchical requirements on the items to which these terms are related. In addition, for example, the reference to the "second" item does not require or exclude the existence of, for example, "first" or lower numbered items or "third" or higher numbered items.

[0018] As used herein, the terms "axial" and "axially" refer to directions and orientations extending substantially parallel to the longitudinal axis of a rotating machine. In addition, the terms "radial" and "radially" refer to directions and orientations extending substantially perpendicular to the longitudinal axis of a rotating machine. In addition, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations extending in an arc around the longitudinal axis of a rotating machine. Further, as used herein, the term "upstream" refers to the front end or inlet end of a rotating machine, and the term "downstream" refers to the rear end or outlet end of a rotating machine. When discussing the flow of fluid through a component, the starting direction of the fluid flow is described as "upstream", and the direction followed by the fluid flow is described as "downstream".

[0019] The method and system described herein relate to a method for emission-compliant operation of a combustor of a gas turbine engine at a lower level than a conventional MECL. More specifically, the gas turbine engine includes a combustor comprising a first combustion zone, a second combustion zone, at least one first fuel nozzle, and at least one second fuel nozzle. At least one first fuel nozzle directs a first fuel flow to the first combustion zone, and at least one second fuel nozzle directs a second fuel flow to the second combustion zone. The fuel split is a fraction of the total fuel flow directed to the second combustion zone. The digital simulation simultaneously determines the current operating temperature of the first combustion zone, and at least one sensor measures the current operating temperature of the exhaust gas of the combustor. In addition, the inlet guide vanes control the air flow to the combustor. When the demand for the gas turbine engine decreases (i.e., when the grid operating company requests the operator of the gas turbine engine to reduce the power generation), the operator of the gas turbine engine can place the gas turbine engine in a response mode and / or a standby mode.

[0020] In the response mode, the operator of the gas turbine engine reduces the fuel split to zero (i.e., shuts down the second combustion zone) to reduce the current operating temperature of the combustor to achieve carbon monoxide emissions compliance, and uses inlet guide vanes to control the air flow to the combustor to maintain the exhaust temperature of the gas turbine engine at or above the minimum exhaust temperature (usually the minimum exhaust temperature required for the operation of the heat exchanger used to operate the steam turbine associated with the power plant). The response mode enables the gas turbine engine to continue to operate at a reduced but non-zero power generation level while maintaining compliance with carbon monoxide emissions requirements.

[0021] In standby mode, the operator of the gas turbine engine reduces the fuel split to zero (i.e., shuts down the second combustion zone) to reduce the current operating temperature of the combustor to achieve carbon monoxide emissions compliance, and uses inlet guide vanes to control the air flow to the combustor to keep the combustor exhaust temperature below the minimum exhaust temperature of the power plant's steam generation system. Standby mode enables the gas turbine engine to continue to operate without generating electricity while maintaining compliance with carbon monoxide emissions requirements.

[0022] Both the response mode and the standby mode enable the gas turbine engine to maintain emissions compliant operation during periods of reduced electricity demand. Thus, when electricity demand increases and the grid operator requests more power generation, the gas turbine engine described herein remains operational, i.e., does not require an extended startup procedure, and will be one of the first generators requested to increase power generation. In some embodiments, eliminating the startup delay that enables such a gas turbine engine to increase power generation again increases revenue for the gas turbine engine operator. Thus, the systems and methods described herein achieve emissions compliant operation of the combustor of the gas turbine engine at less than conventional MECL throughout the period of time when electricity demand has decreased and the grid operator has requested a reduction in power generation.

[0023] Figure 1 1 is a schematic diagram of an exemplary rotary machine 100 (i.e., a turbine), and more specifically a turbine engine. In an exemplary embodiment, the rotary machine 100 is a gas turbine engine. Alternatively, the rotary machine may be any other turbine engine and / or rotary machine, including but not limited to a gas turbofan aircraft engine and / or other aircraft engine. In an exemplary embodiment, the gas turbine engine 100 includes an intake portion 102, a compressor portion 104 coupled downstream of the intake portion 102, a combustor portion 106 coupled downstream of the compressor portion 104, a turbine portion 108 coupled downstream of the combustor portion 106, and an exhaust portion 110 coupled downstream of the turbine portion 108. The turbine portion 108 is coupled to the compressor portion 104 via a rotor shaft 112.

[0024] It should be noted that, as used herein, the term "coupled" is not limited to direct mechanical, thermal, electrical, and / or fluid communication connections between components, but may also include indirect mechanical, thermal, electrical, and / or fluid communication connections between multiple components. In an exemplary embodiment, the combustor section 106 includes a plurality of combustors 114. The combustor section 106 is coupled to the compressor section 104 so that each combustor 114 is in fluid communication with the compressor section 104. The rotor shaft 112 is also coupled to a load 116, such as, but not limited to, a generator and / or a mechanical drive application. In an exemplary embodiment, each of the compressor section 104 and the turbine section 108 includes at least one rotor assembly 118 coupled to the rotor shaft 112.

[0025] In this embodiment, the air intake section 102 includes at least one inlet guide vane 103, which is controlled by an inlet guide vane controller 105. The inlet guide vane 103 controls the flow of inlet air 120, which is guided from the atmosphere to the compressor section 104 by the air intake section 102. Specifically, the inlet guide vane 103 may include a variable or fixed vane 107 that guides the inlet air 120 to the compressor section 104. In addition, the vane 107 of the inlet guide vane 103 may be variable (i.e., the angle of the vane 107 relative to the compressor section 104 may be changed) to change the flow angle of the inlet air 120 under different operating conditions and improve the efficiency of the compressor section 104.

[0026] In an exemplary embodiment, the combustor 114 includes axial fuel staging (AFS) technology (including axial (sequential) combustion staging in at least two zones). Specifically, one or more combustors 114 are axially staged combustors, which include a first combustion zone 115, a second combustion zone 117, at least one first fuel nozzle 119, and at least one second fuel nozzle 121. At least one first fuel nozzle 119 is located upstream of at least one second fuel nozzle 121, and directs a first fuel flow into the first combustion zone 115, which is correspondingly upstream of the second combustion zone 117. At least one second fuel nozzle 121 is located downstream of at least one first fuel nozzle 119 and the first combustion zone 115, and directs a second fuel flow into the second combustion zone 117. The first combustion zone 115 and the second combustion zone 117 stage the total fuel flow to the combustor to control the combustion dynamics within the combustor 114. In an exemplary embodiment, Figure 1 A single first fuel nozzle 119 and a single second fuel nozzle 121 are shown in FIG. However, one or more combustors 114 may include a plurality of first fuel nozzles 119 and / or a plurality of second fuel nozzles 121 .

[0027] In an alternative embodiment, the burner 114 is a single staged burner including multiple combustion zones and multiple nozzle arrays, which guide fuel to each combustion zone within the single staged burner. Therefore, the nozzle array causes the fuel to flow in stages to the single staged burner. In another alternative embodiment, the rotary machine 100 includes two turbines, namely: a high-pressure turbine (not shown) and a low-pressure turbine (not shown). The high-pressure turbine is located between the first burner (not shown) and the second burner (not shown), and the low-pressure turbine is located downstream of the second burner. The high-pressure turbine recovers energy from the combustion gas discharged from the first burner, and the combustion gas is discharged to the second burner. The second burner mixes the combustion gas with the fuel and ignites the combustion gas with the fuel. The combustion gas is then discharged from the second burner to the low-pressure turbine, and the low-pressure turbine recovers energy from the combustion gas discharged from the second burner. In another alternative embodiment, the burner 114 includes more than two burners and / or combustion zones and more than two nozzle arrays, including three or more burners and / or combustion zones and three or more nozzle arrays.

[0028] The rotary machine 100 also includes a fuel supply system 130, which includes at least one valve 132, which controls the fuel diversion of the total fuel flow. The fuel diversion corresponds to the allocation of the total fuel flow to the burner 114 between the first fuel flow and the second fuel flow. In an exemplary embodiment, the fuel diversion is expressed as a fraction of the total fuel flow directed to at least one second fuel nozzle 121 (i.e., the second fuel flow divided by the sum of the first fuel flow and the second fuel flow). Alternatively, the fuel diversion is expressed in any appropriate manner. Specifically, the fuel supply system 130 guides the total fuel flow to the burner 114. More specifically, the fuel supply system 130 guides the total fuel flow to the first fuel nozzle 119 and the second fuel nozzle 121, which in turn guides the total fuel flow to the first combustion zone 115 and the second combustion zone 117, respectively. The valve 132 is controllable and can divert the total fuel flow into the first fuel flow and the second fuel flow according to the selected fuel diversion.

[0029] The rotary machine 100 also includes a computing device 134 that controls at least one operating parameter of the rotary machine 100. More specifically, in the exemplary embodiment, the computing device 134 controls a fuel split of the total fuel flow to the combustor 114 by controlling the valve 132. In addition, the computing device 134 may also send a control signal to the inlet guide vane controller 105 and / or directly control the inlet guide vanes 103 to control the flow of the inlet air 120 directed to the combustor 114. Therefore, the computing device 134 controls the stoichiometry of the combustion reaction within the combustor 114 by controlling the fuel split and the flow of the inlet air 120 to the combustor 114.

[0030] Computing device 134 is also programmed to perform a digital simulation of rotating machine 100 that accurately determines at least one temperature within combustor 114, such as a temperature that is not and / or cannot be directly measured with reliable accuracy. More specifically, the digital simulation accurately determines T within combustor 114. 3.5 and T 3.9 Temperature, for example, in the absence of direct temperature sensor measurement in the first combustion zone 115 and the second combustion zone 117. 3.5 The temperature is the temperature within the first combustion zone 115 and within the combustor 114 axially upstream of the second fuel nozzle 121 and the second combustion zone 117. 3.9 The temperature is the temperature within the combustor 114 within the second combustion zone 117 and axially downstream of the second fuel nozzle 121. As will be discussed in more detail below, the computing device 134 controls the fuel split and the flow rate of the inlet air 120 flowing to the combustor 114 to control T using digital simulation. 3.5 temperature.

[0031] During operation, the air intake section 102 directs inlet air 120 toward the compressor section 104. The computing device 134 and / or the inlet guide vane controller 105 controls the inlet guide vanes 103 to control the flow of the inlet air 120. The compressor section 104 compresses the inlet air 120 to a higher pressure and then discharges the compressed air 122 toward the combustor section 106. The compressed air 122 is delivered to the combustor section 106 where it is mixed with fuel (not shown) and combusted to produce high temperature combustion gases 124. The computing device 134 controls the fuel split to the first fuel nozzle 119 and the second fuel nozzle 121 using digital simulation to control the T in the combustor 114. 3.5Combustion gases 124 are directed downstream toward turbine section 108 and impinge on turbine blades (not shown), converting thermal energy into mechanical rotational energy that is used to drive rotor assembly 118 to rotate about longitudinal axis 126. In general, combustor section 106 and turbine section 108 are referred to as a hot gas section of turbine engine 100. If rotary machine 100 is a gas turbine as part of a combined cycle power plant, exhaust gases 128 are discharged through exhaust section 110 to the ambient atmosphere or a steam turbine (not shown).

[0032] Figure 2A , Figure 2B , Figure 2C and Figure 2D is a flow chart of an exemplary method 200 for emissions compliant operation of a rotary machine 100 below a conventional MECL. Figure 3 300 is a graph of the relationship between the exhaust temperature of the rotating machine 100 and the electrical load of the rotating machine 100. The method 200 includes operating 202 the rotating machine 100 in a normal operating mode (i.e., at a load above a minimum emissions compliance load (MECL) 302) at which electrical power is supplied to the grid. The rotating machine 100 has a MECL 302, which is the lowest load on the rotating machine 100 at which the rotating machine 100 can conventionally operate normally while still complying with emissions standards. More specifically, the MECL 302 is the lowest load on the rotating machine 100 at which T 3.5 The temperature is maintained at a temperature that complies with emission standards, the first combustion zone 115 and the second combustion zone 117 are both in operation, and the exhaust gas 128 is maintained at or above the minimum emission temperature for the combined cycle power plant operation.

[0033] Diagram 300 includes a plurality of line segments 304, 306, 308, and 310 that illustrate potential paths of rotary machine 100 during operation. Specifically, diagram 300 includes historical path 304, exemplary first response mode path 306, exemplary second response mode path 308, and exemplary standby mode path 310. Diagram 300 also includes target T 3.5 The historical path 304 is a path that has been historically followed during startup, operation, and shutdown of the rotary machine 100. The first response mode path 306 and the second response mode path 308 are examples of response modes that enable the rotary machine 100 to continue to operate at a reduced power generation level while maintaining compliance with carbon monoxide emissions requirements (i.e., achieving a target exhaust temperature at a temperature between 100 and 100). 3.5Specifically, in the response mode, the operator of the rotary machine 100 reduces the fuel split to zero (i.e., shuts down the second combustion zone 117), and controls the air flow to the combustor 114 using the inlet guide vanes 103, such as following one of the first response mode path 306 and the second response mode path 308 for achieving carbon monoxide emission compliance, to reduce the T of the first combustion zone 115 and the combustor 114. 3.5 The standby mode path 310 enables the rotary machine 100 to continue to operate without generating electricity while maintaining compliance with carbon monoxide emission requirements. Specifically, in the standby mode, the operator of the rotary machine 100 reduces the fuel split to zero (i.e., shuts down the second combustion zone) and controls the air flow to the combustor using the inlet guide vanes 103 to reduce the T of the first combustion zone 115 and the combustor 114. 3.5 temperature, thereby achieving CO emissions compliance (i.e., reaching a temperature at the target T 3.5 The response mode and the standby mode both enable the rotating machine 100 to maintain emissions compliant operation during periods of reduced electricity demand. Thus, when electricity demand increases and the grid operating company requests more power generation, the rotating machine 100 described herein remains in operation and would be one of the first generators requested to increase power generation, thereby increasing revenue for the operator of the rotating machine 100. Thus, when electricity demand decreases and the grid operating company requests less power generation, the systems and methods described herein achieve exhaust compliant operation of the combustor of the rotating machine 100 below the MECL 302.

[0034] Method 200 also includes receiving 204 a request to reduce power generation when below MECL 302. In an exemplary embodiment, a controller of the power grid determines that excess power is being generated and requests one or more generators to reduce power generation. In alternative embodiments, rather than receiving a request to reduce power generation, rotating machine 100 may be required to reduce power generation for other reasons such as, but not limited to, emergency situations and / or maintenance requirements associated with rotating machine 100, combined cycle power plant, and / or the power grid.

[0035] The method 200 also includes reducing 206 the fuel split to zero. The operator of the rotary machine 100 reduces the fuel split to zero to stop combustion in the second combustion zone 117. The first fuel nozzle 119 continues to direct the first fuel flow into the first combustion zone 115, while the second fuel nozzle 121 stops directing the second fuel flow into the second combustion zone 117. More specifically, the computing device 134 controls the valve 132 to reduce the second fuel flow to zero while maintaining the first fuel flow. Therefore, the first combustion zone 115 is the only combustion zone in operation, and the total fuel flow is not staged to control the combustion dynamics within the combustor 114. In an alternative embodiment, the first fuel flow entering the first combustion zone 115 is also reduced to control T 3.5 temperature.

[0036] The method 200 also includes operating 208 the rotary machine 100 in a response mode, such as the first response mode 306 and / or the second response mode 308. In the response mode, the operator of the rotary machine 100 reduces the fuel split to zero (i.e., shuts down the second combustion zone) and controls the air flow to the combustor 114 using the inlet guide vanes 103 to reduce the T of the first combustion zone 115 and the combustor 114. 3.5 temperature, thereby achieving carbon monoxide emissions compliance and maintaining exhaust gas 128 at or above the minimum exhaust temperature for power plant operation. The rotary machine 100 then begins to operate following the first response mode path 306, for example, as shown in diagram 300. As shown in diagram 300, the first response mode path 306 deviates from the historical path 304 because the second combustion zone 117 is closed and the combustor temperature is controlled by manipulating the combustor inlet airflow. More specifically, because the second combustion zone 117 is closed and the inlet guide vanes are used to control T 3.5 temperature, so the exhaust temperature and T 3.5 temperature decreases. Therefore, load, exhaust temperature and T 3.5 The temperature simultaneously decreases following a first response mode path 306 that is different from the historical path 304 .

[0037] Operating 208 the rotary machine 100 in the responsive mode includes determining 210 the current operating T of the first combustion zone 115 using a digital simulation of the rotary machine 100. 3.5Temperature. The digital simulation is a model of the rotating machine 100. Specifically, the digital simulation is any suitable model that accurately determines the operating state of multiple operating parameters within the rotating machine 100 in real time during the operation of the rotating machine 100 based on control inputs from the computing device 134 and / or feedback from applicable sensors (not shown) located throughout the rotating machine 100. More specifically, the digital simulation is a thermodynamic and fluid dynamic model that accurately determines the operating state of multiple operating parameters within the rotating machine 100 in real time during the operation of the rotating machine 100. The multiple operating parameters determined by the digital simulation include T in the combustor 114. 3.5 and T 3.9 temperature, which cannot usually be directly measured by sensors within the combustion zone. Therefore, the digital simulation determines the T in the combustor 114 in real time during the operation of the rotary machine 100. 3.5 and T 3.9 The determination 210 may be performed continuously while other steps of the method 200 are performed simultaneously. In an alternative embodiment, the determination 210 of the current operating T of the first combustion zone 115 is performed simultaneously. 3.5 The temperature may include determining 210 the current operating T of the first combustion zone 115 using a non-physics-based model of the rotary machine 100 (eg, a state variable model or a neural network). 3.5 temperature.

[0038] Operating 208 the rotating machine 100 in a responsive mode includes determining 212 a target operating T 3.5 In an exemplary embodiment, a target operating temperature is determined 212. 3.5 Temperature includes the use of digital simulation to determine the 212 target operating T 3.5 Temperature. Digital simulation can be repeated to determine the target operating T 3.5 temperature, and determining 210 the actual temperature of the first combustion zone 115 using a digital simulation of the rotary machine 100. More specifically, the target operating temperature T is determined based on the emission standards. 3.5 temperature to ensure that rotating machine 100 operates in accordance with emissions standards. For example, conditions may change (i.e., the grid operator requests rotating machine 100 to increase power generation to a level below MECL 302, the ambient temperature, pressure and / or humidity may change, and / or the fuel temperature may change), and in order for rotating machine 100 to meet load and emissions requirements, the target operating T may need to be updated. 3.5 For example, the demand on the load 116 may increase or decrease, and thus, the operating conditions of the rotary machine 100 may change to accommodate the changing demand on the load 116. Specifically, in order to accommodate the changing demand on the load 116, the target T 3.5 The operating temperature may vary. However, in alternative embodiments, the target operating T 3.5The temperature may be determined by an operator or some other method other than digital simulation and / or may not be repeatedly updated with each control loop. The determination 212 may be performed continuously while other steps of the method 200 are performed simultaneously.

[0039] Operating 208 the rotary machine 100 in the responsive mode includes determining 214 a current temperature of the exhaust gas 128 using at least one sensor (not shown) configured to measure the current operating temperature of the exhaust gas 128. The sensor determines the current temperature of the exhaust gas 128 in real time during operation of the rotary machine 100. In addition, the temperature of the exhaust gas 128 can be sent to a digital simulation and used to determine 210 the current operating T of the first combustion zone 115. 3.5 temperature and / or determine 212 target operating T 3.5 The determination 214 may be performed continuously while other steps of the method 200 are performed simultaneously.

[0040] Operating 208 the rotary machine 100 in the responsive mode includes determining 216 a target temperature of the exhaust gas 128. In an exemplary embodiment, determining 216 the target temperature of the exhaust gas 128 includes determining 216 the target operating T using a digital simulation and / or computing device 134. 3.5 Temperature. The digital simulation and / or computing device 134 may determine 214 the current temperature of the exhaust gas 128 by repeatedly determining the target temperature of the exhaust gas 128 while using the digital simulation and / or computing device 134 of the rotating machine 100. More specifically, the target temperature of the exhaust gas 128 is determined based on the lowest exhaust temperature at which the power plant operates. For example, conditions may change (i.e., the grid operating company requests the rotating machine 100 to increase power generation to a level below the MECL 302), and in order for the rotating machine 100 to meet the load requirements, the target temperature of the exhaust gas 128 needs to be updated. For example, the requirements for the load 116 may increase or decrease, and therefore, the operating conditions of the rotating machine 100 may change to accommodate the changing requirements for the load 116. Specifically, in order to accommodate the changing requirements for the load 116, the temperature of the exhaust gas 128 may change. However, in alternative embodiments, the target temperature of the exhaust gas 128 may be determined by the operator or some other method (e.g., a device controller separate from the rotating machine controller) rather than the digital simulation and / or computing device 134 and / or may not be repeatedly updated with each control cycle. The determination 216 may be performed continuously while other steps of the method 200 are performed simultaneously.

[0041] Operating 208 the rotating machine 100 in the responsive mode also includes comparing 218 the current operating T 3.5 Temperature and target operating T 3.5 Temperature. If the current working T 3.5 Temperature and target operating T 3.5If the temperature is different, the computing device 134 controls the first fuel flow rate and the flow rate of the inlet air 120 so that the current working temperature T 3.5 Temperature changes to target operating T 3.5 Temperature, as described below. Comparison 218 may be performed continuously while other steps of method 200 are performed simultaneously.

[0042] Operating 208 the rotary machine 100 in the responsive mode also includes comparing 220 the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. If the current temperature of the exhaust gas 128 and the target temperature of the exhaust gas 128 are different, the computing device 134 controls the flow of the first fuel and the flow of the inlet air 120 to change the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128, as described below. The comparison 220 can be performed continuously while other steps of the method 200 are performed simultaneously.

[0043] Operating 208 the rotating machine 100 in the responsive mode also includes calculating 222 using the digital simulation and / or computing device 134 to make the current operating T 3.5 Temperature changes to target operating T 3.5 The target first fuel flow rate is calculated by running additional digital simulations of the rotary machine 100 to change the current operating temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to a target first fuel flow rate of the target temperature of the exhaust gas 128 .

[0044] Operating 208 the rotating machine 100 in the responsive mode also includes calculating 224 using the digital simulation and / or computing device 134 to make the current operating T 3.5 Temperature changes to target operating T 3.5 The target flow rate of the inlet air 120 that changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128 can be calculated by running additional digital simulations of the rotary machine 100. 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. Alternatively, the computing device may calculate a target flow rate of the inlet air 120 that changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to a target flow rate of the inlet air 120 at a target temperature of the exhaust gas 128 .

[0045] Operating 208 the rotary machine 100 in the responsive mode also includes controlling 226 the flow rate of the first fuel and the flow rate of the inlet air 120 to cause the current operating T 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. Specifically, the computing device 134 controls the valve 132 to control the first fuel flow rate, and controls the inlet guide vane 103 to control the flow rate of the inlet air 120. The computing device 134 controls the valve 132 to adjust the first fuel flow rate to the target first fuel flow rate, and controls the inlet guide vane 103 to adjust the flow rate of the inlet air 120 to the target flow rate of the inlet air 120. The computing device 134 and the digital simulation control the flow rate of the inlet air 120 and the first fuel flow rate flowing to the first combustion zone 115 to control the stoichiometry of the first combustion zone 115. At the current working T 3.5 The temperature has changed to the target working temperature T 3.5 After the temperature and the current temperature of the exhaust gas 128 has been changed to the target temperature of the exhaust gas 128, the operating state of the rotating machinery 100 is changed, and the digital simulation and / or computing device 134 repeats the method 200 as needed to maintain compliance with emission requirements and keep the exhaust gas 128 at or above the minimum exhaust temperature of the power plant operation.

[0046] As shown in the diagram 300, the exemplary second response mode path 308 extends from the first response mode path 306 and may be employed, for example, when the flow temperature of the inlet air 120 is relatively high. More specifically, for example, when the flow temperature of the inlet air 120 is above 80°F, the second response mode path 308 may be followed by controlling a target burner tube velocity of the first fuel nozzle 119. For example, the target burner tube velocity is a burner tube velocity at which the flame from the first fuel nozzle 119 is pushed into the first combustion zone 115 to avoid flashback or auto-ignition.

[0047] The method 200 also includes operating 228 the rotary machine 100 in the standby mode. In the standby mode, the operator of the rotary machine 100 reduces the fuel split to zero (i.e., shuts down the second combustion zone) and uses the inlet guide vanes 103 to control the air flow to the combustor 114 to reduce the T of the first combustion zone 115 and the combustor 114. 3.5temperature, thereby achieving carbon monoxide emissions compliance and maintaining the exhaust gas 128 below the minimum exhaust temperature for power plant operation (e.g., operation of a heat exchanger used to generate steam for a steam turbine from waste heat in the exhaust gas 128). Because the grid operating company has requested the operator to reduce power generation to below that of the response mode, the operator operates the rotating machine 100 in standby mode rather than in response mode. In some embodiments, the rotating machine 100 first operates in response mode and then, in response to a subsequent request from the grid operating company to reduce power generation, further reduces power generation by operating in standby mode. The rotating machine 100 then begins to operate following, for example, the standby mode path 310 shown in Figure 300. As shown in Figure 300, because the second combustion zone 117 is closed and the burner temperature is controlled by manipulating the burner inlet airflow, the standby mode path 310 deviates from the historical path 304. More specifically, because the second combustion zone 117 is closed and the inlet guide vanes 103 are utilized to control T 3.5 temperature, so the exhaust temperature and T 3.5 temperature decreases. Therefore, load, exhaust temperature and T 3.5 The temperature simultaneously decreases following a standby mode path 310 that is different from the historical path 304 .

[0048] Operating 228 the rotary machine 100 in the standby mode includes determining 230 a current operating T of the first combustion zone 115 using a numerical simulation of the rotary machine 100 . 3.5 Temperature, as described above in determination 210. Determination 230 may be performed continuously while other steps of method 200 are performed simultaneously.

[0049] Operating 228 the rotating machine 100 in the standby mode includes determining 232 a target operating T 3.5 In an exemplary embodiment, a target operating temperature is determined 232. 3.5 Temperature includes the use of digital simulation to determine the 232 target operating T 3.5 Temperature. Digital simulation can be repeated to determine the target operating T 3.5 temperature, and determining 230 the temperature of the first combustion region 115 using a numerical simulation of the rotary machine 100. More specifically, the target operating temperature T is determined based on the emission standard. 3.5 Temperature to ensure that the rotating machine 100 operates in accordance with the emission standards. For example, conditions may change (i.e., the grid operator requests the rotating machine 100 to increase power generation to a level below the MECL 302), and in order for the rotating machine 100 to meet the load and emission requirements, the target operating temperature needs to be updated. 3.5For example, the demand on the load 116 may increase or decrease, and thus, the operating conditions of the rotary machine 100 may change to accommodate the changing demand on the load 116. Specifically, in order to accommodate the changing demand on the load 116, the target T 3.5 The operating temperature may vary. However, in alternative embodiments, the target operating T 3.5 The temperature may be determined by an operator or some other method other than digital simulation and / or may not be repeatedly updated with each control loop. The determination 232 may be performed continuously while other steps of the method 200 are performed simultaneously.

[0050] Operating 228 the rotary machine 100 in the standby mode includes determining 234 a current temperature of the exhaust gas 128 using at least one sensor (not shown) configured to measure the current operating temperature of the exhaust gas 128. The sensor determines the current temperature of the exhaust gas 128 in real time during operation of the rotary machine 100. In addition, the temperature of the exhaust gas 128 can be sent to a digital simulation and used to determine 230 the current operating T of the first combustion zone 115. 3.5 temperature and / or determine 232 target operating T 3.5 The determination 234 may be performed continuously while other steps of the method 200 are performed simultaneously.

[0051] Operating 228 the rotary machine 100 in the standby mode includes determining 236 a target temperature of the exhaust gas 128. In an exemplary embodiment, determining 236 the target temperature of the exhaust gas 128 includes determining 236 a target operating T using a digital simulation and / or computing device 134. 3.5 The digital simulation and / or computing device 134 may determine 234 the current temperature of the exhaust gas 128 using the digital simulation and / or computing device 134 of the rotary machine 100 by repeatedly determining the target temperature of the exhaust gas 128. More specifically, the target temperature of the exhaust gas 128 is determined based on the physical operating limits and the optimal heat rate of the rotary machine 100. The determination 236 may be performed continuously while other steps of the method 200 are performed simultaneously.

[0052] Operating 228 the rotating machine 100 in the standby mode also includes comparing 238 the current operating T 3.5 Temperature and target operating T 3.5 Temperature. If the current working T 3.5 Temperature and target operating T 3.5 If the temperature is different, the computing device 134 controls the first fuel flow rate and the flow rate of the inlet air 120 so that the current working temperature T 3.5 Temperature changes to target operating T 3.5 Temperature, as described below. Comparison 238 may be performed continuously while other steps of method 200 are performed simultaneously.

[0053] Operating 228 the rotary machine 100 in the standby mode also includes comparing 240 the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. If the current temperature of the exhaust gas 128 and the target temperature of the exhaust gas 128 are different, the computing device 134 controls the flow of the first fuel and the flow of the inlet air 120 to change the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128, as described below. The comparison 240 can be performed continuously while other steps of the method 200 are performed simultaneously.

[0054] Operating 228 the rotating machine 100 in the standby mode also includes calculating 242 using the digital simulation and / or computing device 134 to make the current operating T 3.5 Temperature changes to target operating T 3.5 The target first fuel flow rate that changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128 can be calculated by running additional digital simulations of the rotary machine 100. 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. Alternatively, the computing device may calculate a target first fuel flow rate that changes the current operating temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. 3.5 Temperature changes to target operating T 3.5 The target first fuel flow rate determines the temperature and changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128 .

[0055] Operating 228 the rotating machine 100 in the standby mode also includes calculating 244 using the digital simulation and / or computing device 134 to make the current operating T 3.5 Temperature changes to target operating T 3.5 The target flow rate of the inlet air 120 that changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128 can be calculated by running additional digital simulations of the rotary machine 100. 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. Alternatively, the computing device may calculate a target flow rate of the inlet air 120 that changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. 3.5 Temperature changes to target operating T 3.5 temperature and changes the current temperature of the exhaust gas 128 to a target flow rate of the inlet air 120 at a target temperature of the exhaust gas 128 .

[0056] Operating 228 the rotary machine 100 in the standby mode also includes controlling 246 the flow rate of the first fuel and the flow rate of the inlet air 120 so that the current operating T 3.5 Temperature changes to target operating T 3.5temperature and changes the current temperature of the exhaust gas 128 to the target temperature of the exhaust gas 128. Specifically, the computing device 134 controls the valve 132 to control the first fuel flow rate, and controls the inlet guide vane 103 to control the flow rate of the inlet air 120. The computing device 134 controls the valve 132 to adjust the first fuel flow rate to the target first fuel flow rate, and controls the inlet guide vane 103 to adjust the flow rate of the inlet air 120 to the target flow rate of the inlet air 120. The computing device 134 and the digital simulation control the flow rate of the inlet air 120 and the first fuel flow rate flowing to the first combustion zone 115 to control the stoichiometry of the first combustion zone 115. At the current working T 3.5 The temperature has changed to the target working temperature T 3.5 After the temperature is determined and the current temperature of the exhaust gas 128 has been changed to the target temperature of the exhaust gas 128, the operating state of the rotating machine 100 is changed, and the digital simulation and / or computing device 134 repeats the method 200 as needed to maintain compliance with emission requirements and keep the exhaust gas 128 below the minimum exhaust temperature for power plant operation.

[0057] The method 200 also includes receiving 248 a request to increase power generation above the MECL 302 while operating in the response mode or the standby mode. In an exemplary embodiment, a controller of the power grid determines that too little power is being generated and requests one or more generators to increase power generation. In alternative embodiments, instead of receiving a request to increase power generation, the rotating machine 100 may need to increase power generation for other reasons such as, but not limited to, emergency situations and / or maintenance requirements associated with the rotating machine 100, the combined cycle power plant, and / or the power grid.

[0058] The method 200 also includes increasing the fuel split by 250 from zero to a level consistent with normal operation. The operator of the rotary machine 100 increases the fuel split and reignites combustion within the second combustion zone 117. The first fuel nozzle 119 and the second fuel nozzle 121 direct the first fuel flow and the second fuel flow into the first combustion zone 115 and the second combustion zone 117, respectively. More specifically, the computing device 134 controls the valve 132 to increase the second fuel flow while maintaining the first fuel flow. Therefore, the first combustion zone 115 and the second combustion zone 117 are both in operation, and the total fuel flow is staged to control the combustion dynamics within the combustor 114. In an alternative embodiment, the first fuel flow entering the first combustion zone 115 is also reduced to control T 3.5 temperature.

[0059] Method 200 also includes operating 252 rotary machine 100 in a normal operating mode, for example in response to a request to increase power generation. In normal operating mode, the operator of rotary machine 100 increases fuel split to maintain T in compliance with emission requirements.3.5 The temperature is determined and the air flow to the combustor 114 is controlled by the inlet guide vanes 103 to maintain the exhaust gas 128 at or above the minimum exhaust temperature of the power plant. Then, the rotary machine 100 begins to follow the history path 304 shown in the diagram 300.

[0060] The method 200 may be implemented with a rotary machine 100 having an optional burner 114 layout. For example, the method 200 may be implemented with multiple burners 114 including a single staged burner, the single stage burner including multiple nozzle arrays as described above. In addition, the method 200 may be implemented with a rotary machine 100 including a high pressure turbine located between a first burner and a second burner and a low pressure turbine located downstream of the second burner as described above. In addition, the method 200 may be implemented with any burner 114 layout that enables the rotary machine 100 to operate as described herein.

[0061] The above-mentioned system and method relate to a method for emission-compliant operation of a combustor of a gas turbine engine at a lower level than a conventional MECL. More specifically, the gas turbine engine includes a combustor, which includes a first combustion zone, a second combustion zone, at least one first fuel nozzle, and at least one second fuel nozzle. At least one first fuel nozzle directs a first fuel flow to the first combustion zone, and at least one second fuel nozzle directs a second fuel flow to the second combustion zone. The fuel split is a fraction of the total fuel flow directed to the second combustion zone. The digital simulation simultaneously determines the current operating temperature of the first combustion zone, and at least one sensor measures the current operating temperature of the exhaust gas of the gas turbine. In addition, the inlet guide vanes control the air flow to the combustor. When the demand for the gas turbine engine decreases (i.e., when the grid operating company requests the operator of the gas turbine engine to reduce power generation), the operator of the gas turbine engine can place the gas turbine engine in a response mode and / or a standby mode.

[0062] In the responsive mode, the operator of the gas turbine engine reduces the fuel split to zero (i.e., shuts down the second combustion zone) and utilizes inlet guide vanes to control the air flow to the combustor to reduce the current operating temperature of the combustor to comply with the carbon monoxide emission requirements and to maintain the exhaust temperature of the combustor at or above the minimum exhaust temperature at which the steam generation system of the power plant operates. The responsive mode enables the gas turbine engine to continue to be operated by the combined cycle power plant at a reduced power generation level while maintaining compliance with the carbon monoxide emission requirements.

[0063] In standby mode, the operator of the gas turbine engine reduces the fuel split to zero (i.e., shuts down the second combustion zone) and uses inlet guide vanes to control the air flow to the combustor to reduce the current operating temperature of the combustor to comply with the carbon monoxide emission requirements and to keep the combustor exhaust temperature below the minimum exhaust temperature at which the power plant's steam generation system operates. Standby mode enables the gas turbine engine to continue to operate in the absence of combined cycle power plant power generation while maintaining compliance with carbon monoxide emission requirements.

[0064] Both the response mode and the standby mode enable the gas turbine engine to maintain emissions compliant operation during periods of reduced electricity demand. Thus, when electricity demand increases and the grid operator requests more generation, the gas turbine engine described herein remains operational and would be one of the first generators requested to increase generation, thereby increasing revenue for the operator of the gas turbine engine. Thus, when electricity demand decreases and the grid operator requests less generation, the systems and methods described herein achieve exhaust compliant operation of the combustor of the gas turbine engine at less than conventional MECL.

[0065] In addition, an exemplary technical effect of the systems and methods described herein includes at least one of the following steps: (a) controlling the temperature of a first combustion zone of a combustor; (b) controlling an electrical load generated by a gas turbine engine; and (c) controlling air flow to a compressor and a combustor.

[0066] Exemplary embodiments of systems and methods for emission-compliant operation of a combustor of a gas turbine engine at less than conventional MECL are described above in detail. The systems and methods are not limited to the specific embodiments described herein, but rather the components of the system and / or steps of the method may be used independently and separately from other components and / or steps described herein. For example, the method may also be used in conjunction with other rotating machines and is not limited to practice with only a gas turbine engine as described herein. Rather, the exemplary embodiments may be implemented and used in conjunction with many other rotating machine applications.

[0067] Although specific features of various embodiments of the present disclosure may be shown in some drawings and not in other drawings, this is for convenience only. According to the principles of the embodiments of the present disclosure, any feature of the drawings may be referenced and / or claimed in combination with any feature of any other drawings.

[0068] This written description uses examples to disclose embodiments of the present disclosure, including the best mode, and also enables any person skilled in the art to practice the embodiments of the present disclosure, including making and using any device or system and performing any combined method. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A method (200) for operating a rotary machine (100) in a responsive mode (306) below a minimum emissions compliance load (302), the rotary machine (100) comprising a combustor (106), the combustor comprising a first combustion zone (115) and a second combustion zone (117), the method (200) comprising: i) reducing (206) a fuel split to zero, wherein the fuel split is a fraction of the total fuel flow directed to the second combustion zone (117); ii) determining (210) a current operating temperature of the first combustion zone (115) using a digital simulation of the rotating machine (100); iii) determining (212) a target operating temperature for the first combustion zone (115), wherein the target operating temperature enables the rotating machine (100) to operate below the minimum emissions compliance load (302) while still complying with emissions standards; iv) directing a first fuel flow to the first combustion zone (115), wherein the first fuel flow reduces the temperature of the first combustion zone (115) to the target operating temperature; and v) Repeating steps i to iv until the rotating machine (100) operates below the minimum emission compliance load (302) and complies with emission standards.

2. The method (200) of claim 1, further comprising determining (214) a current temperature of exhaust gas from the rotary machine (100).

3. The method (200) of claim 2, further comprising determining (216) a target temperature of the exhaust gas to be equal to or higher than a minimum exhaust gas temperature at which the power plant operates.

4. The method (200) of claim 3, further comprising comparing (218) the current temperature of the exhaust gas to the target temperature of the exhaust gas.

5. The method (200) of claim 4, further comprising calculating (222) a target inlet air flow rate for reducing the temperature of the first combustion zone (115) to the target operating temperature and reducing the current temperature of the exhaust gas to the target temperature of the exhaust gas.

6. The method (200) of claim 5, further comprising directing an air flow to the first combustion zone (115), wherein the air flow reduces the temperature of the exhaust gas from the current temperature to the target temperature.

7. A method (200) for operating a rotary machine (100) in a standby mode below a minimum emissions compliance load (302), the rotary machine (100) comprising a combustor (106), the combustor comprising a first combustion zone (115) and a second combustion zone (117), the method (200) comprising: i) reducing (206) a fuel split to zero, wherein the fuel split is a fraction of the total fuel flow directed to the second combustion zone (117); ii) determining (210) a current operating temperature of the first combustion zone (115) using a digital simulation of the rotating machine (100); iii) determining (212) a target operating temperature for the first combustion zone (115), wherein the target operating temperature enables the rotating machine (100) to operate below the minimum emissions compliance load (302) while still complying with emissions standards; iv) directing a first fuel flow to the first combustion zone (115), wherein the first fuel flow reduces the temperature of the first combustion zone (115) to the target operating temperature and reduces the temperature of exhaust gas from the rotating machine (100) to below a minimum exhaust temperature for power plant operation; and v) Repeating steps i to iv until the rotating machine (100) operates below the minimum emission compliance load (302) and complies with emission standards.

8. The method (200) of claim 7, further comprising determining (214) a current temperature of the exhaust gas from the rotary machine (100).

9. The method (200) of claim 8, further comprising determining (216) that the target temperature of the exhaust gas is lower than a minimum exhaust gas temperature at which the power plant operates.

10. The method (200) of claim 9, further comprising comparing (218) the current temperature of the exhaust gas to the target temperature of the exhaust gas.

11. The method (200) of claim 10, further comprising calculating (222) a target inlet air flow rate that reduces the temperature of the first combustion zone (115) to the target operating temperature and reduces the current temperature of the exhaust gas to the target temperature of the exhaust gas.

12. The method (200) of claim 11, further comprising directing an air flow to the first combustion zone (115), wherein the air flow reduces the temperature of the exhaust gas from the current temperature to the target temperature.

13. A rotating machine (100), comprising: a compressor (104) configured to compress an inlet air flow; A burner (106), the burner comprising a first combustion zone (115), a second combustion zone (117), at least one first fuel nozzle (119), and at least one second fuel nozzle (121), wherein the at least one first fuel nozzle (119) is configured to direct a first fuel flow rate to the first combustion zone (115), and the at least one second fuel nozzle (121) is configured to direct a second fuel flow rate to the second combustion zone (117), and wherein the burner (106) is configured to receive the inlet air flow rate, and wherein the fuel split is a fraction of the total fuel flow rate directed to the second combustion zone (117); and A computing device (134) comprising a digital simulation of the rotating machine (100), the computing device (134) being configured to operate the rotating machine (100) in a responsive mode (306), wherein the computing device (134) is configured to: i) reducing (206) the fuel split to zero; ii) determining (210) a current operating temperature of the first combustion zone (115) using a digital simulation of the rotating machine (100); iii) determining (212) a target operating temperature for the first combustion zone (115), wherein the target operating temperature enables the rotating machine (100) to operate below a minimum emissions compliance load (302) while still complying with emissions standards; iv) directing a first fuel flow to the first combustion zone (115), wherein the first fuel flow reduces the temperature of the first combustion zone (115) to the target operating temperature; and v) Repeat steps i to iv until the rotating machine (100) operates below the minimum emission compliance load (302) and complies with emission standards.

14. The rotary machine (100) of claim 13, further comprising a fuel supply system (130) configured to direct the total fuel flow to the first combustion zone (115) and the second combustion zone (117).

15. The rotary machine (100) of claim 14, wherein the fuel supply system (130) comprises at least one valve (132) configured to split the total fuel flow into the first fuel flow and the second fuel flow.

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