Duct burner control device and duct burner control method

Abstract

To enable operating a duct burner so as to bring the NOx concentration of exhaust gas to equal to or less than a regulation value in accordance with the exhaust gas discharged from a gas turbine.SOLUTION: A duct burner control device for controlling a duct burner disposed in an exhaust gas flow channel where exhaust gas discharged from a gas turbine circulates includes: an input data acquisition part for acquiring input data including a temperature of exhaust gas, an oxygen concentration of exhaust gas, and a flow quantity of exhaust gas at an upstream side of the exhaust gas flow channel than the duct burner, and the property of gas turbine fuel charged into the gas turbine; and an output data calculation part for calculating, based on the input data acquired by the input data acquisition part, output data including the amount of duct burner fuel charged into the duct burner, and a discharge side Nox concentration corresponding to the amount of duct burner fuel as a concentration of a nitric oxide contained in exhaust gas at a downstream side of the exhaust gas flow channel with respect to the duct burner.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a duct burner control device and a duct burner control method for controlling a duct burner disposed in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows. [Background technology]

[0002] For example, as disclosed in Non-Patent Document 1, in a gas turbine cogeneration system equipped with a gas turbine and a heat recovery boiler, a duct burner may be provided upstream of the heat recovery boiler in order to increase the amount of heat recovered by the heat recovery boiler. The duct burner injects fuel into the exhaust gas discharged from the gas turbine and performs combustion heating by utilizing the oxygen contained in the exhaust gas. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] IHI Technical Report VOL.49 No.2(2009-6) P103-P107 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable that the concentration of nitrogen oxides (NOx) contained in exhaust gas is as small as possible. In conventional gas turbine cogeneration systems, when the NOx concentration in exhaust gas exceeds a regulated value set by the national or local government, the system is operated by reducing NOx using a method such as water or steam injection in the combustor or adjusting the amount of ammonia water injected into the denitrification device so that the NOx concentration in exhaust gas is below the regulated value. However, there is a demand for operation while suppressing as much as possible the decrease in thermal efficiency caused by water or steam injection and the increase in the amount of ammonia water used. Therefore, the present inventors have considered controlling the operation of the duct burner to reduce the NOx concentration in exhaust gas to below the regulated value.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a duct burner control device and a duct burner control method that are capable of operating a duct burner in accordance with the exhaust gas discharged from a gas turbine so as to reduce the NOx concentration of the exhaust gas to below a regulated value. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the duct burner control device disclosed herein is a duct burner control device that controls a duct burner arranged in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows, and includes an input data acquisition unit that acquires input data including the temperature of the exhaust gas upstream of the duct burner in the exhaust gas flow path, the oxygen concentration of the exhaust gas, the flow rate of the exhaust gas, and the properties of the gas turbine fuel input to the gas turbine, and an output data calculation unit that calculates, based on the input data acquired by the input data acquisition unit, output data including the amount of duct burner fuel input to the duct burner and the NOx concentration, which is the concentration of nitrogen oxides contained in the exhaust gas downstream of the duct burner in the exhaust gas flow path and corresponds to the amount of the duct burner fuel.

[0007] In order to achieve the above-mentioned object, the duct burner control method disclosed herein is a duct burner control method for controlling a duct burner arranged in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows, and includes the steps of acquiring input data including the temperature of the exhaust gas upstream of the duct burner in the exhaust gas flow path, the oxygen concentration of the exhaust gas, the flow rate of the exhaust gas, and properties of the gas turbine fuel input to the gas turbine, and calculating, based on the input data, output data including the amount of duct burner fuel input to the duct burner, and the NOx concentration, which is the concentration of nitrogen oxides contained in the exhaust gas downstream of the duct burner in the exhaust gas flow path and corresponds to the amount of the duct burner fuel. Effect of the Invention

[0008] According to the duct burner control device and duct burner control method disclosed herein, it is possible to operate the duct burner in accordance with the exhaust gas discharged from the gas turbine so as to reduce the amount of NOx contained in the exhaust gas to below a regulated value. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a schematic configuration of a gas turbine system including a duct burner control device according to an embodiment. [Diagram 2] 1 is a diagram illustrating a schematic configuration of a duct burner according to an embodiment of the present invention. [Diagram 3] 1 is a schematic functional block diagram of a duct burner control device according to one embodiment. FIG. [Figure 4A] 4 is a graph showing the relationship between outlet NOx concentration and the amount of duct burner fuel. [Figure 4B] 4 is a graph showing the relationship between outlet NOx concentration and the amount of duct burner fuel. [Diagram 5] 4 is a flowchart of a method for controlling a duct burner according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a duct burner control device and a duct burner control method according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment shows one aspect of the present disclosure, and does not limit the present disclosure. The embodiment can be modified as desired within the scope of the technical concept of the present disclosure.

[0011] <Gas turbine system> Fig. 1 is a diagram showing a schematic configuration of a gas turbine system 100 including a duct burner control device 1 according to an embodiment. As shown in Fig. 1, the gas turbine system 100 includes a gas turbine 110, an exhaust gas passage 120 through which exhaust gas G discharged from the gas turbine 110 flows, a duct burner 50 arranged in the exhaust gas passage 120, a heat recovery boiler 130 arranged downstream of the exhaust gas passage 120 from the duct burner 50, a denitrification device 140 arranged downstream of the exhaust gas passage 120 from the exhaust heat recovery boiler 130, and a chimney 150 connected to the downstream end of the exhaust gas passage 120.

[0012] The gas turbine 110 includes a compressor 112, a combustor 114, and a turbine 116. The compressor 112 compresses air A1 supplied from the outside to generate compressed air A2. The combustor 114 generates combustion gas A4 by injecting gas turbine fuel A3 into the compressed air A2 generated by the compressor 112 and combusting it. The gas turbine fuel A3 is, but is not limited to, hydrogen gas. In some embodiments, the gas turbine fuel A3 is a hydrocarbon gas such as LPG or LNG.

[0013] The turbine 116 is rotationally driven by the passage of the combustion gas A4 generated by the combustor 114, and converts thermal energy of the combustion gas A4 into rotational energy. The turbine 116 is connected to the compressor 112 via a rotating shaft 113, and transmits the rotational energy to the compressor 112. The compressor 112 is driven by using the rotational energy of the turbine 116. In the embodiment illustrated in Fig. 1, the gas turbine system 100 further includes a generator 160 connected to the rotating shaft 113. The generator 160 generates electric power by using the rotational energy of the turbine 116.

[0014] The exhaust gas passage 120 is defined by an inner wall surface 124 of a duct 122 having, for example, a rectangular cylindrical shape (see FIG. 2). The exhaust gas passage 120 is configured so that the exhaust gas G flows from the gas turbine 110 toward the chimney 150. The exhaust gas G flows through the duct burner 50, the exhaust heat recovery boiler 130, and the denitration device 140 in this order.

[0015] Hereinafter, the exhaust gas G flowing upstream of the exhaust gas passage 120 from the duct burner 50 is referred to as inlet-side exhaust gas G1 (G), the exhaust gas G flowing downstream of the exhaust heat recovery boiler 130 and upstream of the exhaust gas passage 120 from the denitration device 140 is referred to as outlet-side exhaust gas G2 (G), and the exhaust gas G flowing downstream of the exhaust gas passage 120 from the denitration device 140 is referred to as purified exhaust gas G3 (G). In one embodiment, the inlet-side exhaust gas G1 is the exhaust gas G flowing at the inlet of the duct burner 50 or immediately upstream of the inlet of the duct burner 50. The inlet of the duct burner 50 is positioned so as to overlap with a fuel supply pipe 52 described later in the direction in which the exhaust gas passage 120 extends, for example.

[0016] FIG. 2 is a diagram showing a schematic configuration of a duct burner 50 according to an embodiment. The duct burner 50 burns the duct burner fuel F by utilizing oxygen contained in the inlet-side exhaust gas G1, and heats the inlet-side exhaust gas G1. As shown in FIG. 2, the duct burner 50 includes a fuel supply pipe 52, a nozzle 54, and a flame holder 56. The fuel supply pipe 52 extends along the left-right direction of the exhaust gas passage 120. The fuel supply pipe 52 has a cylindrical shape, and the duct burner fuel F supplied from a supply source (not shown) flows inside the fuel supply pipe 52. The duct burner fuel F is, but is not limited to, hydrogen gas. In some embodiments, the duct burner fuel F is a hydrocarbon gas such as LPG or LNG. In some embodiments, the duct burner 50 includes a plurality of fuel supply pipes 52 arranged at intervals from each other along the vertical direction.

[0017] The nozzle 54 is connected to the fuel supply pipe 52 and ejects the duct burner fuel F toward the downstream side of the exhaust gas passage 120. The flame stabilizer 56 has a pair of plate-shaped members 58A, 58B located on opposite sides of the nozzle 54 in the vertical direction. Each of the pair of plate-shaped members 58A, 58B has a plurality of through holes 59 formed therein, and is made of, for example, punched metal. The pair of plate-shaped members 58A, 58B are arranged so that at least a portion of them overlap each other in the left-right direction when viewed from the downstream side of the exhaust gas passage 120 (viewed from the front). In some embodiments, a plurality of nozzles 54 are connected to one fuel supply pipe 52.

[0018] The heat recovery boiler 130 generates steam by heating feed water using thermal energy of the inlet side exhaust gas G1 heated by the duct burner 50. The denitration device 140 purifies nitrogen oxides (NOx) contained in the outlet side exhaust gas G2 from which thermal energy has been recovered by the heat recovery boiler 130. Specifically, as shown in FIG. 2, the denitration device 140 is a so-called urea SCR system, and includes an SCR catalyst 142 arranged in the exhaust gas flow passage 120, and a urea water injection device 144 arranged upstream of the SCR catalyst 142 and injecting urea water B. Such a urea SCR system reduces NOx contained in the outlet side exhaust gas G2 to nitrogen on the SCR catalyst 142 using ammonia generated by hydrolysis of the urea water B as a reducing agent. The chimney 150 releases the purified exhaust gas G3 into the atmosphere.

[0019] 1, the gas turbine system 100 further includes a display device 180 such as a monitor. The display device 180 is electrically connected to the duct burner control device 1.

[0020] The duct burner control device 1 controls the duct burner 50 arranged in the exhaust gas flow path 120. The duct burner control device 1 is installed upstream of the duct burner 50 in the exhaust gas flow path 120 and is electrically connected to various sensors configured to acquire information related to the inlet-side exhaust gas G1. In the embodiment illustrated in Fig. 1, the gas turbine system 100 includes a temperature sensor 170 that measures the temperature of the inlet-side exhaust gas G1, a concentration sensor 172 that measures the oxygen concentration contained in the inlet-side exhaust gas G1, and a flow rate sensor 174 that measures the flow rate of the inlet-side exhaust gas G1.

[0021] <Duct burner control device> (composition) A specific configuration of the duct burner control device 1 will be described. The duct burner control device 1 is a computer such as an electronic control device, and includes a processor such as a CPU or GPU (not shown), memories such as a ROM and RAM, and an I / O interface. The duct burner control device 1 realizes each of the functional units of the duct burner control device 1 by the processor operating (calculating, etc.) according to instructions of a program loaded into the memory. Each of the functional units of the duct burner control device 1 according to one embodiment will be described with reference to FIG. 3. In some embodiments, the duct burner control device 1 is a cloud server provided in a cloud environment.

[0022] Fig. 3 is a schematic functional block diagram of a duct burner control device 1 according to one embodiment. As shown in Fig. 3, the duct burner control device 1 includes an input data acquisition unit 2, an output data calculation unit 4, an operation execution unit 6, a fuel adjustment unit 8, an operation condition acquisition unit 10, a reducing agent increase unit 12, and a display unit 14.

[0023] The input data acquiring unit 2 acquires input data Di including the temperature of the inlet side exhaust gas G1, the oxygen concentration of the inlet side exhaust gas G1, the flow rate of the inlet side exhaust gas G1, and the properties of the gas turbine fuel A3. The input data acquiring unit 2 acquires the temperature of the inlet side exhaust gas G1 from the temperature sensor 170, the oxygen concentration of the inlet side exhaust gas G1 from the concentration sensor 172, and the flow rate of the inlet side exhaust gas G1 from the flow rate sensor 174. Furthermore, the input data acquiring unit 2 acquires the properties of the gas turbine fuel A3 by being input in advance by an operator. The properties of the gas turbine fuel A3 are the ratios of components contained in the gas turbine fuel A3, for example, the ratios of hydrogen, CO, hydrocarbons, CO2, N2, and H2O. In some embodiments, the input data acquiring unit 2 is configured to acquire the NOx concentration of the inlet side exhaust gas G1.

[0024] In one embodiment, the input data acquisition unit 2 acquires the temperature of the inlet side exhaust gas G1, the oxygen concentration of the inlet side exhaust gas G1, and the flow rate of the inlet side exhaust gas G1 from sensors (temperature sensor 170, concentration sensor 172, and flow rate sensor 174), respectively. However, the present disclosure is not limited to this form. In some embodiments, the input data acquisition unit 2 acquires the temperature of the inlet side exhaust gas G1, the oxygen concentration of the inlet side exhaust gas G1, and the flow rate of the inlet side exhaust gas G1, which are estimated based on the operation information (load, heat value, etc.) of the gas turbine 110. In some embodiments, the input data acquisition unit 2 acquires the properties of the gas turbine fuel A3, which are estimated based on the heat value.

[0025] The output data calculation unit 4 inputs the input data Di into a model created in advance to calculate the output data Do including the amount of duct burner fuel F and the outlet side NOx concentration C. In other words, the output data calculation unit 4 calculates the prediction result of the NOx concentration of the outlet side exhaust gas G2. The outlet side NOx concentration C is the concentration of NOx contained in the outlet side exhaust gas G2 and corresponds to the amount of the duct burner fuel F. FIGS. 4A and 4B are graphs showing the relationship between the outlet side NOx concentration C and the amount of the duct burner fuel F, where the horizontal axis represents the amount of the duct burner fuel F and the vertical axis represents the outlet side NOx concentration C. In some embodiments, the output data Do further includes the oxygen concentration of the outlet side exhaust gas G2. With this configuration, it is possible to easily grasp the combustion amount of the gas turbine fuel A3 and the load of the gas turbine 110.

[0026] Although not shown, in some embodiments, the gas turbine system 100 further includes a NOx concentration sensor that measures the NOx concentration contained in the outlet side exhaust gas G2. The duct burner control device 1 is electrically connected to this NOx concentration sensor, and acquires the NOx concentration (actual NOx concentration) of the outlet side exhaust gas G2. The output data calculation unit 4 is configured to perform machine learning on the model by comparing the outlet side NOx concentration C with the NOx concentration of the outlet side exhaust gas G2. With this configuration, the input data Di can be input to the machine-learned model to calculate highly accurate output data Do.

[0027] According to the findings of the present inventors, it has been found that when the inlet side exhaust gas G1, whose temperature and oxygen concentration satisfy predetermined conditions, is burned and heated by the duct burner 50, the NOx contained in the inlet side exhaust gas G1 is reduced and the concentration of NOx is reduced. On the other hand, when the inlet side exhaust gas G1 does not satisfy the predetermined conditions, the concentration of NOx contained in the inlet side exhaust gas G1 is increased. The predetermined conditions are, for example, that the temperature of the exhaust gas G is 500 degrees or less and the oxygen concentration is 14% or less.

[0028] As shown in FIG. 4A, when the inlet side exhaust gas G1 satisfies a predetermined condition, the outlet side NOx concentration C decreases as the amount of the duct burner fuel F increases. As shown in FIG. 4B, when the inlet side exhaust gas G1 does not satisfy a predetermined condition, the outlet side NOx concentration C increases as the amount of the duct burner fuel F increases. The threshold value X of the outlet side NOx concentration C is determined in advance, for example, as a regulated value determined by the country or a local government, or is determined based on this regulated value. Each of FIG. 4A and FIG. 4B shows the threshold value X. Also, each of FIG. 4A and FIG. 4B shows a plot P indicating the present. When the plot P is located at the left end of the horizontal axis, it means that the duct burner fuel F is not being input into the duct burner 50.

[0029] The operation execution unit 6 operates the duct burner 50 when the outlet side NOx concentration C included in the output data Do has a decreasing tendency to decrease as the amount of the duct burner fuel F increases as shown in FIG. 4A. Specifically, the operation execution unit 6 transmits an operation signal P1 to the duct burner 50 when the outlet side NOx concentration C has a decreasing tendency. When the duct burner 50 receives the operation signal P1 while stopped, the duct burner 50 starts operation. When the duct burner 50 receives the operation signal P1 while operating, the duct burner 50 continues operation. In one embodiment, the duct burner 50 is charged with an amount of duct burner fuel F that makes the outlet side NOx concentration C smaller than the threshold value X based on the graph shown in FIG. 4A. In this case, the amount of duct burner fuel F may be increased or decreased from the current amount of duct burner fuel F.

[0030] Incidentally, the method for adjusting the amount of duct burner fuel F is not particularly limited, but is carried out by adjusting the opening of a valve provided in the fuel supply pipe 52, for example.

[0031] When the outlet side NOx concentration C tends to increase as the amount of duct burner fuel F increases as illustrated in FIG. 4B, the fuel adjustment unit 8 adjusts the amount of duct burner fuel F input to the duct burner 50 so that the outlet side NOx concentration C is less than the threshold value X. Specifically, when the outlet side NOx concentration C tends to increase, the fuel adjustment unit 8 transmits a fuel signal P2 to the duct burner 50. The fuel signal P2 includes an amount of duct burner fuel F that makes the outlet side NOx concentration C smaller than the threshold value X. Upon receiving the fuel signal P2, the duct burner 50 operates with the amount of duct burner fuel F included in the fuel signal P2. For example, when the plot P exceeds the threshold value X, the duct burner 50 operates by reducing the amount of duct burner fuel F.

[0032] The operating condition acquisition unit 10 acquires the operating condition P3 of the exhaust heat recovery boiler 130. The operating condition P3 is, for example, the amount of steam required for the exhaust heat recovery boiler 130. When the outlet side NOx concentration C corresponding to the amount of duct burner fuel F required to satisfy the operating condition P3 exceeds the threshold value X, the reducing agent increase unit 12 stops the fuel adjustment unit 8. Furthermore, the reducing agent increase unit 12 increases the amount of urea water B supplied from the denitration device 140. Specifically, the reducing agent increase unit 12 cancels the fuel signal P2 transmitted by the fuel adjustment unit 8 to the duct burner 50. Furthermore, the reducing agent increase unit 12 transmits a reduction signal P4 to the denitration device 140. The reduction signal P4 includes an increased amount of urea water B. When the denitration device 140 receives the reduction signal P4, the amount of urea water B is increased to the amount included in the reduction signal P4 and is operated.

[0033] The display unit 14 causes the outlet side NOx concentration C to be displayed on the display device 180. Specifically, the display unit 14 transmits a display signal P5 to the display device 180. The display signal P5 includes output data Do. Upon receiving the display signal P5, the display device 180 displays the output data Do included in the display signal P5. The display device 180 displays, for example, graphs such as those illustrated in FIG. 4A and FIG. 4B.

[0034] (Action and effect) The operation and effect of the duct burner control device 1 according to one embodiment will be described. According to one embodiment, the output data Do including the outlet side NOx concentration C corresponding to the amount of the duct burner fuel F is calculated based on the input data Di including the temperature of the inlet side exhaust gas G1 and the oxygen concentration of the inlet side exhaust gas G1. Therefore, the outlet side NOx concentration C can be predicted from the calculated output data Do. Therefore, the amount of the duct burner fuel F can be adjusted so that the NOx concentration of the exhaust gas G is equal to or lower than the threshold value X according to the exhaust gas G (temperature and oxygen concentration) discharged from the gas turbine 110, and the duct burner 50 can be operated. Furthermore, according to one embodiment, the input data Di includes the flow rate of the inlet side exhaust gas G1 and the properties of the gas turbine fuel A3, so that the calculation accuracy of the output data Do (the accuracy of the prediction result) can be improved.

[0035] According to one embodiment, when the outlet side NOx concentration C is on a decreasing trend, the duct burner 50 is operated. Therefore, while the inlet side exhaust gas G1 is combusted and heated by the duct burner 50, the NOx concentration of the inlet side exhaust gas G1 can be reduced by the duct burner 50.

[0036] According to one embodiment, when the outlet side NOx concentration C is on the increase, the amount of duct burner fuel F input to the duct burner 50 is adjusted so that the outlet side NOx concentration C is less than the threshold value X. Therefore, while the inlet side exhaust gas G1 is combusted and heated by the duct burner 50, the NOx concentration of the outlet side exhaust gas G2 can be prevented from exceeding the threshold value X.

[0037] Depending on the operating conditions of the heat recovery boiler 130, there is a demand to avoid stopping the operation of the duct burner 50, or to operate the duct burner 50 without reducing the amount of the duct burner fuel F. According to one embodiment, even if the outlet side NOx concentration C corresponding to the amount of the duct burner fuel F required to satisfy the operating conditions of the heat recovery boiler 130 exceeds the threshold value X, the adjustment of the amount of the duct burner fuel F by the fuel adjustment unit 8 is stopped, and the amount of the urea water B supplied from the denitration device 140 is increased. Therefore, by making the NOx concentration of the outlet side exhaust gas G2 less than the threshold value X by the urea water B supplied from the denitration device 140, the amount of the duct burner fuel F can be set arbitrarily (avoiding the operation stop or the reduction in the amount of the duct burner fuel F).

[0038] According to one embodiment, the output data Do is displayed on the display device 180, so that an operator can know the NOx concentration of the outlet side exhaust gas G2 in advance by visually checking the display device 180. In addition, the operator can adjust the amount of duct burner fuel F to be input to the duct burner 50 based on the output data Do.

[0039] <Duct burner control method> A control method for a duct burner 50 according to one embodiment will be described. Fig. 5 is a flowchart of the control method for the duct burner 50 according to one embodiment. The control method for the duct burner 50 controls the duct burner 50 arranged in an exhaust gas flow passage 120 through which exhaust gas G discharged from a gas turbine 110 flows. As shown in Fig. 5, such a duct burner 50 includes an input data acquisition step S1 for acquiring input data Di, and an output data calculation step S2 for calculating output data Do based on the input data Di acquired in the input data acquisition step S1.

[0040] According to this method, the amount of duct burner fuel F can be adjusted to operate the duct burner 50 in accordance with the exhaust gas G (temperature and oxygen concentration) discharged from the gas turbine 110 so that the NOx concentration of the exhaust gas G becomes equal to or lower than the threshold value X. Furthermore, since the input data Di includes the flow rate of the inlet side exhaust gas G1 and the properties of the gas turbine fuel A3, the calculation accuracy of the output data Do (accuracy of the prediction result) can be improved.

[0041] The contents described in each of the above embodiments can be understood, for example, as follows.

[0042] [1] The duct burner control device (1) according to the present disclosure is A duct burner control device for controlling a duct burner (50) disposed in an exhaust gas flow path (120) through which exhaust gas (G) discharged from a gas turbine (110) flows, comprising: an input data acquisition unit (2) that acquires input data (Di) including a temperature of the exhaust gas upstream of the duct burner in the exhaust gas passage, an oxygen concentration of the exhaust gas, a flow rate of the exhaust gas, and properties of a gas turbine fuel (A3) that is input to the gas turbine; and an output data calculation unit (4) that calculates, based on the input data acquired by the input data acquisition unit, output data (Do) including an amount of duct burner fuel (F) to be input to the duct burner and an outlet side NOx concentration (C) which is a concentration of nitrogen oxides contained in the exhaust gas downstream of the duct burner in the exhaust gas flow passage and corresponds to the amount of the duct burner fuel.

[0043] According to the findings of the present inventors, it was found that when exhaust gas, the temperature and oxygen concentration of which satisfy respective predetermined conditions, is burned and heated by a duct burner, the concentration of NOx contained in the exhaust gas is reduced. According to the configuration described in [1] above, output data including an outlet side NOx concentration corresponding to the amount of duct burner fuel is calculated based on input data including the temperature and oxygen concentration of the exhaust gas. Therefore, using the calculated output data, the duct burner can be operated (by adjusting the amount of duct burner fuel) according to the exhaust gas (temperature and oxygen concentration) discharged from the gas turbine so that the NOx concentration of the exhaust gas is equal to or lower than the regulated value. Furthermore, according to the configuration described in [1] above, the input data includes the flow rate of the exhaust gas and the properties of the gas turbine fuel, so that the calculation accuracy of the output data can be improved.

[0044] [2] In some embodiments, in the configuration described in [1] above, The system further includes an operation execution unit (6) that operates the duct burner when the outlet NOx concentration included in the output data has a decreasing tendency to decrease as the amount of the duct burner fuel increases.

[0045] According to the configuration described in [2] above, when the outlet NOx concentration is on a downward trend, the duct burner is operated to combust and heat the exhaust gas while reducing the NOx concentration of the exhaust gas by the duct burner.

[0046] [3] In some embodiments, in the configuration described in [1] or [2] above, The system further includes a fuel adjustment unit (8) that adjusts the amount of duct burner fuel input to the duct burner so that the outlet NOx concentration becomes less than a predetermined threshold value (X) when the outlet NOx concentration included in the output data shows an increasing tendency to increase as the amount of duct burner fuel increases.

[0047] According to the configuration described in [3] above, when the outlet-side NOx concentration is on the rise, the NOx concentration in the exhaust gas can be prevented from exceeding the threshold value X while the exhaust gas is combusted and heated by the duct burner.

[0048] [4] In some embodiments, in the configuration described in [3] above, an operating condition acquisition unit (10) that acquires operating conditions of a heat recovery steam generator (130) that is disposed downstream of the exhaust gas flow path with respect to the duct burner; and a reducing agent increasing unit (12) that, when the outlet-side NOx concentration corresponding to the amount of the duct burner fuel necessary to satisfy the operating conditions exceeds the threshold value, stops the fuel adjustment unit and increases the amount of a reducing agent (B) supplied from a denitration device (140) that is located downstream of the heat recovery boiler in the exhaust gas flow path.

[0049] According to the configuration described in [4] above, the amount of duct burner fuel can be set at any amount by making the NOx concentration in the exhaust gas below a threshold value using the reducing agent supplied from the denitration device.

[0050] [5] In some embodiments, in the configuration according to any one of [1] to [4] above, The exhaust gas purification system further includes a display unit (14) for displaying the outlet NOx concentration on a display device (180).

[0051] According to the configuration described in [5] above, an operator can visually check the display device to know in advance the NOx concentration of the exhaust gas flowing downstream of the duct burner in the exhaust gas passage.

[0052] [6] In some embodiments, in the configuration according to any one of [1] to [5] above, The output data calculation unit is configured to perform machine learning by comparing the outlet NOx concentration with an actual concentration of nitrogen oxides downstream of the duct burner in the exhaust gas passage.

[0053] According to the configuration described in [6] above, it is possible to cause the output data calculation section to calculate highly accurate output data.

[0054] [7] The duct burner control method according to the present disclosure comprises: A duct burner control method for controlling a duct burner (50) disposed in an exhaust gas flow path (120) through which exhaust gas (G) discharged from a gas turbine (110) flows, comprising: A step (S1) of acquiring input data (Di) including a temperature of the exhaust gas at an upstream side of the exhaust gas flow passage from the duct burner, an oxygen concentration of the exhaust gas, a flow rate of the exhaust gas, and properties of a gas turbine fuel (A3) to be input to the gas turbine; and a step (S2) of calculating output data (Do) including an amount of duct burner fuel (F) input to the duct burner based on the input data, and an outlet side NOx concentration (C) which is a concentration of nitrogen oxides downstream of the duct burner in the exhaust gas flow passage and corresponds to the amount of duct burner fuel.

[0055] According to the method described in [7] above, the duct burner can be operated (by adjusting the amount of duct burner fuel) in accordance with the exhaust gas (temperature and oxygen concentration) discharged from the gas turbine so that the NOx concentration of the exhaust gas is below the regulated value. Furthermore, according to the method described in [7] above, the input data includes the flow rate of the exhaust gas and the properties of the gas turbine fuel, so that the calculation accuracy of the output data can be improved. [Explanation of symbols]

[0056] 1 Duct burner control device 2. Input data acquisition section 4. Output data calculation section 6 Operation Execution Department 8 Fuel adjustment section 10. Operation condition acquisition section 12 Reducing agent increase section 14 Display section 50 Duct Burner 52 Fuel supply pipe 54 Nozzle 56 Flame holder 58A Plate-shaped member (upper side) 58B Plate-shaped member (lower side) 59 Through hole 100 Gas Turbine System 110 Gas Turbine 112 Compressor 113 Rotational Axis 114 Combustor 116 Turbine 120 Exhaust gas flow path 122 Duct 124 Inner wall surface of duct 130 Waste heat recovery boiler 140 Denitration equipment 142 Catalyst 144 Urea water injection device 150 Chimney 160 Generator 170 Temperature Sensor 172 Concentration Sensor 174 Flow Sensor 180 Display device A1 Air A2 Compressed air A3 Gas turbine fuel A4 Combustion gas B Urea water C Outlet side NOx concentration Di Input data Do output data F Duct burner fuel G. Exhaust gas G1 Inlet exhaust gas G2 Outlet exhaust gas G3 Purified exhaust gas P1 Operation signal P2 fuel signal P3 Operating conditions P4 Redox signal P5 display signal S1 Input data acquisition step S2 Output data calculation step X Threshold

Claims

1. A duct burner control device for controlling a duct burner disposed in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows, an input data acquisition unit that acquires input data including a temperature of the exhaust gas upstream of the duct burner in the exhaust gas flow passage, an oxygen concentration of the exhaust gas, a flow rate of the exhaust gas, and properties of a gas turbine fuel input to the gas turbine; and an output data calculation unit that calculates, based on the input data acquired by the input data acquisition unit, an amount of duct burner fuel input to the duct burner and output data including an outlet side NOx concentration, which is a concentration of nitrogen oxides contained in the exhaust gas downstream of the duct burner in the exhaust gas flow passage and corresponds to the amount of the duct burner fuel. Duct burner control device.

2. and an operation execution unit that operates the duct burner when the outlet side NOx concentration included in the output data shows a decreasing trend as the amount of the duct burner fuel increases. The duct burner control device according to claim 1.

3. and a fuel adjusting unit that adjusts the amount of the duct burner fuel input to the duct burner so that the outlet NOx concentration is less than a predetermined threshold value when the outlet NOx concentration included in the output data shows an increasing tendency to increase as the amount of the duct burner fuel increases. The duct burner control device according to claim 1 or 2.

4. an operating condition acquisition unit that acquires operating conditions of a heat recovery steam generator that is disposed downstream of the exhaust gas flow path relative to the duct burner; and a reducing agent increasing unit that stops the fuel adjusting unit and increases an amount of reducing agent supplied from a denitration device disposed downstream of the exhaust gas flow passage from the exhaust heat recovery boiler when the outlet side NOx concentration corresponding to the amount of the duct burner fuel required to satisfy the operating condition exceeds the threshold value. The duct burner control device according to claim 3.

5. Further comprising a display unit that displays the outlet side NOx concentration on a display device. The duct burner control device according to claim 1 or 2.

6. The output data calculation unit is configured to perform machine learning by comparing the outlet NOx concentration with an actual concentration of nitrogen oxides downstream of the duct burner in the exhaust gas passage. The duct burner control device according to claim 1 or 2.

7. A duct burner control method for controlling a duct burner disposed in an exhaust gas flow path through which exhaust gas discharged from a gas turbine flows, comprising: acquiring input data including a temperature of the exhaust gas upstream of the duct burner in the exhaust gas flow passage, an oxygen concentration of the exhaust gas, a flow rate of the exhaust gas, and properties of a gas turbine fuel input to the gas turbine; and calculating, based on the input data, an amount of duct burner fuel input to the duct burner, and output data including an outlet side NOx concentration, which is a concentration of nitrogen oxides contained in the exhaust gas downstream of the duct burner in the exhaust gas passage and corresponds to the amount of the duct burner fuel. A duct burner control method.

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