JP2024042824A - BOILER CONTROL DEVICE, BOILER CONTROL METHOD, AND BOILER CONTROL PROGRAM - Google Patents

Abstract

[Problem] By improving the spatial deviation of the air ratio inside the furnace, good exhaust gas performance is achieved even when ammonia is co-firing. [Solution] A boiler control device for controlling a boiler that burns carbon fuel and ammonia in a furnace, comprising an index parameter acquisition unit, an operation parameter adjustment amount calculation unit, and an operation parameter adjustment unit. The index parameter acquisition unit acquires index parameters for evaluating the air ratio for each of a plurality of regions corresponding to a plurality of pairs of ejection nozzles. The operation parameter adjustment amount calculation unit calculates adjustment amounts for at least a portion of a plurality of operation parameters that have a correlation with the air ratio in each of the plurality of regions, so that the air ratio for each region evaluated based on the index parameters approaches uniformity. The operation parameter adjustment unit adjusts at least a portion of the plurality of operation parameters based on the adjustment amounts. [Selected Figure] Figure 1

Description

The present disclosure relates to a boiler control device, a boiler control method, and a boiler control program.

A large-sized boiler such as a power generation boiler has a hollow furnace installed in a substantially vertical direction, and a plurality of burners are arranged on the wall of the furnace. Further, in a large boiler, a flue is connected vertically above the furnace, and a heat exchanger for generating steam is disposed in the flue. A flame is formed by the burner injecting a mixture of fuel and air (oxidizing gas) into the furnace, and combustion gas is generated and flows into the flue. A heat exchanger is installed in a region where combustion gas flows, and superheated steam is generated by heating water or steam flowing through heat transfer tubes that make up the heat exchanger.

In this type of boiler, in order to remove nitrogen oxides (NOx) contained in the combustion gas, ammonia (NH3) is supplied to the combustion gas, and nitrogen oxidation is performed using a catalyst in the presence of ammonia. Reduction of things takes place. Such a denitrification reaction is expressed by the following chemical reaction formula.
4NO+4NH3+O2→4N2+6H2O...(1)
For example, Patent Document 1 discloses an example of a technique for removing nitrogen oxides from boiler exhaust gas by a denitrification reaction using ammonia.

JP2009-228918A

By the way, in a facing combustion type boiler in which a large number of burners installed on the furnace wall are arranged so as to face each other, the coal fuel (pulverized fuel) produced by pulverizing coal in a pulverized coal mill is composed of multiple coal fuels. Coal fuel is supplied to the burners via a plurality of branch conveyance paths branching off from a main conveyance path connected to a supply source of coal fuel. The lengths of these plurality of branch conveyance paths vary depending on the coal fuel burner to which they are connected, depending on the bend pattern, for example. Since coal fuel is a solid powder fuel, the amount of coal fuel supplied to each coal fuel burner varies considerably depending on the length of the branch conveyance path. On the other hand, each burner is also supplied with an oxidizing gas (air) that is mixed with the coal fuel, but the air-like gas is distributed relatively evenly even if the length of its conveyance path is different. be done. As a result, a spatial deviation of the air ratio occurs within the furnace of the boiler. Such a spatial deviation in the air ratio causes a deviation in the NOx concentration of the exhaust gas at the furnace outlet, and becomes a factor in deteriorating the performance of the boiler.

Further, as in Patent Document 1, it is known that ammonia, which is used in a denitrification reaction to remove nitrogen oxides contained in combustion gas of a boiler, can efficiently transport and store hydrogen at low cost. Therefore, in addition to its role as an energy carrier, ammonia can be used directly as a fuel for thermal power generation, and as a fuel that does not emit CO2 during combustion, it is expected to have great advantages in reducing greenhouse gas emissions. Therefore, development of an ammonia co-fired boiler that co-fires coal fuel and ammonia is underway by using ammonia as a fuel along with coal fuel. According to the verification conducted by the present inventors, it has been found that during such ammonia co-firing, the NOx sensitivity to the air ratio is higher than when only coal fuel is used as the fuel. Therefore, in the ammonia co-fired boiler, there is a problem that the above-mentioned spatial deviation of the air ratio in the furnace increases the deviation of the NOx concentration of the exhaust gas, and the exhaust gas performance tends to deteriorate.

At least one embodiment of the present disclosure has been made in view of the above-mentioned circumstances, and includes a boiler control device that can achieve good exhaust gas performance even during ammonia co-firing by improving the spatial deviation of the air ratio in the furnace; The purpose of the present invention is to provide a boiler control method and a boiler control program.

In order to solve the above problems, a boiler control device according to at least one embodiment of the present disclosure has the following features:
In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control device for controlling a boiler,
an index parameter acquisition unit for acquiring index parameters for evaluating the air ratio for each of the plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. an operation parameter adjustment amount calculation unit for calculating;
an operation parameter adjustment unit for adjusting at least a portion of the plurality of operation parameters based on the adjustment amount;
Equipped with

In order to solve the above problems, a boiler control method according to at least one embodiment of the present disclosure includes:
In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control method for controlling a boiler, comprising:
obtaining index parameters for evaluating air ratios for each of a plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. The process of calculating,
adjusting at least a portion of the plurality of operating parameters based on the adjustment amount;
Equipped with

In order to solve the above problems, a boiler control program according to at least one embodiment of the present disclosure,
In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control program for controlling a boiler,
to the computer,
obtaining index parameters for evaluating air ratios for each of a plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. The process of calculating,
adjusting at least a portion of the plurality of operating parameters based on the adjustment amount;
and is executable.

According to at least one embodiment of the present disclosure, a boiler control device, a boiler control method, and a boiler control capable of achieving good exhaust gas performance even during ammonia co-firing by improving the spatial deviation of the air ratio in the furnace. program can be provided.

FIG. 1 is a schematic configuration diagram of a boiler according to an embodiment. FIG. 2 is a schematic diagram showing the arrangement of burners in the AA cross section of FIG. 1. FIG. FIG. 1 is a block diagram showing the configuration of a boiler control device according to an embodiment. 1 is a flowchart illustrating a boiler control method according to an embodiment. FIG. 2 is a schematic diagram of a burner arrangement layout in a furnace according to an embodiment. FIG. 2 is a schematic diagram of a concentration measuring section provided on the BB cross section in FIG. 1. FIG. FIG. 13 is a diagram showing a concentration distribution in a concentration measurement unit before adjustment of operation parameters. FIG. 7 is a diagram showing the concentration distribution in the concentration measuring section after adjusting the operating parameters. 1 is an example of correlation data that defines a correlation between an index parameter and an operation parameter. This is an example of optimal value data that defines a combination of optimal values of operating parameters corresponding to each region for each operating condition. It is a schematic diagram of the arrangement|positioning layout of the burner in the furnace based on other embodiment. It is a schematic diagram of the arrangement|positioning layout of the burner in the furnace based on other embodiment.

An embodiment according to the present disclosure will be described below with reference to the drawings. It should be noted that the present invention is not limited to this embodiment, and if there are multiple embodiments, the present invention may be configured by combining each embodiment. In the following description, the term "above" or "upper" refers to the upper side in the vertical direction, and "lower" or "lower" refers to the lower side in the vertical direction, and the vertical direction is not exact and includes errors.

First, with reference to FIG. 1, the configuration of a boiler that is an object to be controlled by a boiler control device will be described. FIG. 1 is a schematic configuration diagram of a boiler according to one embodiment, and FIG. 2 is a schematic diagram showing the arrangement of burners in the AA cross section of FIG. 1.

The boiler 10 is an ammonia co-firing boiler that burns carbon fuel and ammonia (NH3) using a burner 21 and exchanges the heat generated by this combustion with feed water or steam to generate superheated steam. The carbon fuel used is biomass fuel or coal, which is crushed to form pulverized fuel.

The boiler 10 has a furnace 11, a combustion device 20, and a combustion gas passage 12. The furnace 11 has a hollow shape of a substantially rectangular cylinder and is installed along a substantially vertical direction. The furnace wall 17, which constitutes the inner wall surface of the furnace 11, is composed of a plurality of heat exchanger tubes and fins that connect the heat exchanger tubes, and converts the heat generated by combustion of fuel into water and steam flowing inside the heat exchanger tubes. In addition to recovering heat by exchanging heat with the furnace wall 17, the temperature rise of the furnace wall 17 is suppressed.

Combustion device 20 is installed in the lower region of furnace 11 . In this embodiment, the combustion device 20 includes a plurality of burners 21 attached to the furnace wall 17. Burner 21 burns carbon fuel or ammonia together with oxidizing gas (secondary air). In this embodiment, the plurality of burners 21 attached to the furnace wall 17 include a carbon fuel burner having a carbon fuel injection nozzle for injecting carbon fuel as a fuel into the furnace 11, and a carbon fuel burner having a carbon fuel injection nozzle for injecting carbon fuel as a fuel into the furnace 11. (In the present specification, when carbon fuel burners and ammonia burners are collectively referred to without distinction, they are simply referred to as "burners"). The proportion and arrangement layout of the carbon fuel burner or ammonia burner among the plurality of burners 21 included in the combustion device 20 can be set as appropriate, and some examples thereof will be specifically shown in the embodiments described below.

In this embodiment, each burner 21 included in the combustion device 20 is configured to be either a carbon fuel burner having a carbon fuel injection nozzle or an ammonia burner having an ammonia injection nozzle. A mode in which fuel and ammonia are burned in different burners 21 will be described. However, the combustion device 20 may be configured to include a burner 21 that includes both a carbon fuel injection nozzle and an ammonia injection nozzle so that carbon fuel and ammonia are combusted in a common burner.

The plurality of burners 21 are provided in multiple stages along the vertical direction with respect to the furnace wall 17 . In this embodiment, a case is shown in which a plurality of burners 21 are provided in three stages. FIG. 2 shows an arrangement layout on a substantially horizontal plane of the burner 21 belonging to the uppermost stage among the burners 21 in the plurality of stages. In this example, the furnace 11 has a substantially rectangular cross section, and each burner 21 is arranged along the furnace width direction on two mutually opposing surfaces 17A and 17B. Each of the burners 21A1, 21A2, . . . arranged on the surface 17A forms a pair by opposing each of the burners 21B1, 21B2, . . . arranged on the surface 17B. Specifically, burners 21A1 and 21B1 constitute a pair of burners facing each other, and burners 21A2 and 21B2 constitute a pair of burners facing each other (the same applies to other pairs of burners). These multiple pairs of burners are arranged along the furnace width direction.

Note that the shape of the furnace 11, the number of stages of burners 21, the number of burners 21 in one stage, the arrangement of burners 21, etc. are not limited to the present embodiment unless otherwise specified.

Each burner 21 is supplied with carbon fuel or ammonia as the fuel to be used through a predetermined transport path. The carbon fuel supplied to the burner 21 is generated as pulverized fuel by a mill, for example. Although not shown in the present specification, the mill is, for example, a vertical roller mill in which a grinding table is supported inside so that it can be driven and rotated, and a plurality of grinding rollers are supported above the grinding table so that they can rotate in conjunction with the rotation of the grinding table. The solid fuel pulverized by the cooperation of the grinding rollers and the grinding table is transported to a classifier provided in the mill by primary air (carrier gas, oxidizing gas) supplied to the mill. In the classifier, the fuel is classified into pulverized fuel with a particle size equal to or smaller than that suitable for combustion in the burner 21 and coarse pulverized fuel with a particle size larger than that. The pulverized fuel passes through the classifier and is supplied to the burner 21 together with the primary air. The coarse pulverized fuel that does not pass through the classifier falls onto the grinding table by its own weight inside the mill and is re-pulverized.

Further, air supplied from a forced draft fan (not shown) is heated by an air preheater and supplied to each burner 21 as secondary air (combustion air, oxidizing gas). The secondary air supplied to each burner 21 is introduced into the furnace 11 from an air jet nozzle provided in each burner 21 .

The combustion gas passage 12 is connected to the upper part of the furnace 11 in the vertical direction. The combustion gas passage 12 is provided with a superheater, a reheater, a economizer, etc. as a heat exchanger for recovering the heat of the combustion gas, and the combustion gas generated in the furnace 11 and each heat exchanger are provided. Heat exchange takes place between the supply water and steam flowing inside the tank.

A flue 13 is connected to the downstream side of the combustion gas passage 12, through which the combustion gas whose heat has been recovered by the heat exchanger is discharged. The flue 13 may be provided with an air preheater for preheating secondary air with the combustion gas flowing through the flue 13 and a denitration device for removing and reducing nitrogen oxides in the combustion gas. Further, a gas duct is connected to the downstream side of the flue 13, and the combustion gas is discharged from the chimney as exhaust gas to the outside of the system via the gas duct. Gas ducts are equipped with environmental devices such as dust collectors such as electrostatic precipitators that remove ash from combustion gases and desulfurization devices that remove sulfur oxides, as well as induced ventilation to guide exhaust gas to these environmental devices. An Induced Draft Fan (IDF) may be provided.

In the boiler 10, carbon fuel (pulverized fuel) or ammonia is supplied to the burner 21. The burner 21 is also supplied with secondary air heated by an air preheater. The burner 21 blows a mixture of these carbon fuels or ammonia and secondary air into the furnace 11 . The air-fuel mixture blown into the furnace 11 is ignited and a flame is formed. When a flame is formed in the lower region within the furnace 11 , hot combustion gases rise within the furnace 11 and flow into the combustion gas passage 12 . In this embodiment, air is used as the oxidizing gas (primary air, secondary air), but it may have a higher or lower oxygen content than air, and the oxygen content relative to the amount of fuel supplied may be By adjusting the ratio of amounts within an appropriate range, stable combustion is achieved in the furnace 11.

Further, above the mounting position of the burner 21 of the furnace 11, a plurality of additional air ports (AA ports) 25 are provided for supplying additional combustion air (AA) into the furnace 11. A portion of the air supplied from the forced draft fan is supplied to the additional air port 25 as additional air for combustion.

The combustion gas that has flowed into the combustion gas passage 12 exchanges heat with water and steam in the superheater, reheater, and economizer arranged inside the combustion gas passage 12, and then is discharged into the flue 13 and is passed through the denitrification device. Nitrogen oxides are removed in the air preheater, and after heat exchange with primary air and secondary air in the air preheater, it is further discharged into the gas duct, ash etc. are removed in the dust collector, and sulfur oxides are removed in the desulfurizer. Afterwards, it is discharged out of the system through the chimney.
Note that the arrangement of each heat exchanger in the combustion gas passage 12 and each device from the flue 13 to the gas duct does not necessarily have to be arranged in the above described order with respect to the combustion gas flow.

Next, a boiler control device 100 for controlling the boiler 10 having the above configuration will be explained. FIG. 3 is a block diagram showing the configuration of the boiler control device 100 according to one embodiment.

The boiler control device 100 includes, for example, a CPU (Central Processing
It is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. A series of processes for realizing various functions is stored in a storage medium, etc. in the form of a program, for example, and the CPU reads this program into a RAM, etc., and executes information processing and arithmetic processing. By doing so, various functions are realized. Note that the program may be pre-installed in a ROM or other storage medium, provided as being stored in a computer-readable storage medium, or distributed via wired or wireless communication means. etc. may also be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

The boiler control device 100 includes an index parameter acquisition section 110, an operation parameter adjustment amount calculation section 120, and an operation parameter adjustment section 130.

The index parameter acquisition unit 110 is configured to acquire an index parameter Pi for evaluating the air ratio of the furnace 11. The index parameter Pi can be any parameter that has a correlation with the air ratio, and is obtained for each region set in the furnace 11. As shown in FIG. 2, a plurality of pairs of burners 21 are arranged in the furnace width direction in the furnace 11, and the space of the furnace 11 is divided to correspond to each pair of burners 21. A plurality of regions 40-1, 40-2, . 21A2 and 21B2). The index parameter acquisition unit 110 acquires the index parameter Pi as an index for evaluating the air ratio in the plurality of regions 40-1, 40-2, . . . defined in this way.

The operation parameter adjustment amount calculation unit 120 is configured to calculate the adjustment amount of the operation parameter Po adjusted by the operation parameter adjustment unit 130. Specifically, based on the index parameters Pi acquired for each region by the index parameter acquisition unit 110, the distribution of the air ratio across the multiple regions 40-1, 40-2, ... is estimated, and the adjustment amount of the operation parameter Po to make the distribution of the air ratio closer to uniformity is calculated. The operation parameter Po is correlated with the air ratio of each region 40-1, 40-2, ... and is an arbitrary parameter that can be adjusted as a control target.

The operation parameter adjustment section 130 is configured to adjust the operation parameter Po using the adjustment amount calculated by the operation parameter adjustment amount calculation section 120. As a result, even if there is a spatial deviation in the air ratio of the furnace 11 based on the air ratio distribution over a plurality of regions 40-1, 40-2, . . . The air ratio distribution over the regions 40-1, 40-2, . . . can be made nearly uniform, and exhaust gas performance can be improved.

Next, a boiler control method implemented using the boiler control device 100 having the above configuration will be described. FIG. 4 is a flowchart illustrating a boiler control method according to one embodiment.

First, the index parameter acquisition unit 110 acquires index parameters Pi for evaluating the air ratio for each of the plurality of regions 40-1, 40-2, . . . (step S1). For example, as in the embodiment described later, the index parameter Pi may be the concentration of NOx or O2 that has a correlation with the air ratio of each region, or the The supply amount may be carbon fuel, ammonia, or oxidizing gas (secondary air).

Subsequently, based on the index parameter Pi acquired in step S1, it is determined whether the air ratio deviation of the furnace 1 is equal to or greater than a threshold value (step S2). In step S2, first, an air ratio distribution over a plurality of regions 40-1, 40-2,... is determined based on the index parameter Pi, and the air ratio The deviation is calculated. The threshold value is preset as a threshold value for determining whether adjustment of the operating parameters is necessary due to a large air ratio deviation.

If the air ratio deviation is equal to or greater than the threshold (step S2: YES), it is determined that there is a variation in the air ratio distribution across the multiple regions 40-1, 40-2, ... that needs to be corrected, and the operation parameter adjustment amount calculation unit 120 calculates the adjustment amount of the operation parameter Po (step S3). The operation parameter adjustment unit 130 then adjusts the operation parameter Po based on the adjustment amount calculated in step S3, thereby controlling the distribution of the air ratio across the multiple regions 40-1, 40-2, ... so as to approach uniformity (step S4).

Note that if the air ratio deviation is less than the threshold value (step S2: NO), the boiler control device 100 determines that the air ratio is already so uneven that it is not necessary to equalize it by adjusting the operating parameter Po, and ends the series of processes. do.

Next, the configuration of the boiler control device 100 and details of the boiler control method will be described with reference to specific embodiments. FIG. 5 is a schematic diagram of the arrangement layout of the burners 21 in the furnace 11 according to one embodiment, FIG. 6 is a schematic diagram of the concentration measuring section 60 provided on the BB cross section of FIG. 1, and FIGS. 7B is a diagram showing the concentration distribution in the concentration measuring section 60 before and after adjusting the operating parameters, respectively.

As shown in FIG. 5, in this embodiment, the plurality of burners 21A1, 21A2, . The plurality of burners 21B1, 21B2, . That is, in this embodiment, one side (surface 17A side) of each pair of burners 21 is an ammonia burner, and the other side (surface 17B) is configured as a carbon fuel burner.

Ammonia is supplied from an ammonia supply source (not shown) to the multiple burners 21A1, 21A2, ... which are ammonia burners. A main ammonia transport pipe 50 is connected to the ammonia supply source, and the main ammonia transport pipe 50 branches into multiple branch ammonia transport pipes 52-1, 52-2, ... for each burner 21A1, 21A2, .... Each of the multiple branch ammonia transport pipes 52 is provided with multiple flow rate adjustment valves 54-1, 54-2, ... for adjusting the flow rate of ammonia to each burner 21A1, 21A2, ....

Further, carbon fuel is supplied to the plurality of burners 21B1, 21B2, . . . which are carbon fuel burners from a carbon fuel supply source (not shown). A carbon fuel main transport pipe 56 is connected to the carbon fuel supply source, and the carbon fuel main transport pipe 56 is connected to a plurality of carbon fuel branch transport pipes 58-1, 58 for each burner 21B1, 21B2, . Branches to -2,...

Figure 6 also shows a cross section of the furnace 11 at the concentration measurement unit 60 provided on the B-B cross section of Figure 1. The concentration measurement unit 60 is provided downstream of the area of the furnace 11 where the components capable of supplying fuel and air are arranged (i.e. downstream of the AA port 25). The concentration measurement unit 60 can measure the concentration of NOx, which is a gas component that is correlated with the air ratio, for each of the areas 60-1, 60-2, ... obtained by dividing the internal space of the furnace 11 along the furnace width direction. The areas 60-1, 60-2, ... correspond to the areas 40-1, 40-2, ... shown in Figure 5, respectively. The concentration measurement unit 60 can determine the NOx concentration distribution across multiple areas 60-1, 60-2, ... by measuring the NOx concentration for each of the areas 60-1, 60-2, ....

As described above with reference to FIG. 1, since the present embodiment has a configuration in which a plurality of burners 21 are arranged facing each other, the NOx concentration distribution in the plurality of regions 60-1, 60-2, . . . , the NOx concentration distribution in the plurality of regions 40-1, 40-2, . . . Further, the method of measuring the NOx concentration distribution by the concentration measuring section 60 is not limited, and various known methods can be employed. Further, the concentration measurement unit 60 may measure O2, which is a gas component that has a correlation with the air ratio like NOx.

FIG. 7A shows the NOx concentration distribution before the operating parameter Po is adjusted by the operating parameter adjustment unit 130. Here, as shown in FIG. 5, a plurality of carbon fuel branch conveyor pipes 58-1, 58-2, . . . connected to a plurality of burners 21B1, 21B2, . Although they are branched from the carbon fuel main conveyance pipe 56, their lengths vary considerably depending on the positions of the burners 21B1, 21B2, . . . to which they are branched. Therefore, considerable variation occurs in the amount of carbon fuel supplied from the plurality of carbon fuel branch conveyance pipes 58-1, 58-2, . . . to each region 40-1, 40-2, . The NOx concentration distribution shown in FIG. 7A is generated. This NOx concentration distribution shows that the NOx concentration is maximum in region 60-2, while the NOx concentration is minimum in region 60-6.

In this embodiment, in step S1, the NOx concentration measured by the concentration measurement unit 60 is acquired as the index parameter Pi. In step S2, the NOx concentration distribution shown in FIG. 7A is identified, and the air ratio deviation is evaluated as the difference between the maximum and minimum values of the NOx concentration contained in the NOx concentration distribution. If it is determined in step S3 that the air ratio deviation is equal to or greater than the threshold value, in step S4, the adjustment amount of the operating parameter Po is calculated based on the air ratio deviation.

In one embodiment, the adjustment amount of the operating parameter Po in step S4 is calculated so as to reduce the maximum value of the NOx concentration included in the NOx concentration distribution. In the example of FIG. 7A, since the NOx concentration in the region 40-2 (or region 60-2) is maximum, the operating parameter adjustment amount calculation unit 120 corresponds to the region 40-2 (or region 60-2). The opening degree of the flow rate adjustment valve 54-2 that can control the flow rate of ammonia in the burner 21A2, which is an ammonia burner, is selected as the operating parameter Po, and an adjustment amount is calculated to increase the opening degree. As a result, the flow rate of ammonia to the region 40-2 (or the region 60-2) is increased, so that the NOx concentration is adjusted to decrease as shown in FIG. 7B.

In another embodiment, the adjustment amount of the operation parameter Po in step S4 is calculated so as to increase the minimum value of the NOx concentration included in the NOx concentration distribution. In the example of FIG. 7A, since the NOx concentration in region 40-6 (or region 60-6) is at a minimum, the operation parameter adjustment amount calculation unit 120 selects the aperture of the flow rate control valve 54-6 capable of controlling the ammonia flow rate in burner 21A6, which is the ammonia burner corresponding to region 40-6 (or region 60-6), as the operation parameter Po, and calculates an adjustment amount to decrease the aperture. As a result, the flow rate of ammonia for region 40-6 (or region 60-6) is decreased, and the NOx concentration is adjusted to increase, as shown in FIG. 7B.

In another embodiment, the adjustment amount of the operation parameter Po in step S4 may be calculated based on correlation data 70 that defines the correlation between the index parameter Pi and the operation parameter Po. FIG. 8 is an example of correlation data 70 that defines the correlation between the index parameter Pi and the operation parameter Po. In this example, the correlation between the NOx concentration, which is an example of the index parameter Pi, and the opening degree of the flow rate adjustment valve 54, which is an example of the operating parameter Po, is expressed by a predetermined function. The operation parameter adjustment amount calculation unit 120 calculates the necessary adjustment amount of the index parameter Pi based on the appropriate range of the index parameter Pi (for example, the allowable range of variation in NOx concentration), and applies the necessary adjustment amount to the correlation data 70. By converting, the amount of adjustment of the operating parameter Po can be obtained.

Note that since the correlation data 70 depends on the operating conditions of the boiler 10, different correlation data 70 may be prepared in the database for each operating condition. In this case, the operating parameter adjustment unit 130 may select correlation data 70 corresponding to the operating conditions of the boiler 10 from the database, and calculate the adjustment amount of the operating parameter Po using the selected correlation data 70. The operating conditions of the boiler 10 can be defined by, for example, the boiler load, information on the burners used, the ammonia co-firing rate, and the like.

In another embodiment, the adjustment amount of the operating parameter Po in step S4 may be calculated such that the value of the operating parameter Po corresponding to each region becomes an optimal value predefined for each operating condition. In this case, the optimal value predefined for each operating condition may be registered in the database as optimal value data 80 in advance. FIG. 9 is an example of optimal value data 80 that defines the combination of optimal values of the operating parameters Po corresponding to each region for each operating condition. In this example, the optimum value of the operating parameter Po for each region is defined for each operating condition defined by the boiler load, information on the burner used, ammonia co-firing rate, and coal type (type of coal fuel). The operating parameter adjustment amount calculation unit 120 acquires optimal value data 80 corresponding to the operating conditions of the boiler 10 from the database, and adjusts the operating parameter Po so that it becomes the optimal value of the operating parameter Po specified in the optimal value data 80. Calculate the adjustment amount.

In other embodiments, the adjustment amount of the operating parameter Po in step S4 may be calculated using a machine learning model. In this case, the machine learning model is constructed using parameters including the operating conditions of the boiler 10 and the index parameter Pi as explanatory variables, and using the adjustment amount of the operating parameter Po as an objective variable. By performing learning using sufficient training data including explanatory variables and objective variables, it is possible to suitably predict the amount of adjustment of the operating parameter Po for making the air ratio in each region close to uniform.

Next, another embodiment will be described with reference to Figure 10. Figure 10 is a schematic diagram of the layout of the burners 21 in the furnace 11 according to another embodiment.

In this embodiment, the multiple burners 21A1, 21A2, ... arranged on surface 17A of the furnace 11 and the multiple burners 21B1, 21B2, ... arranged on surface 17B are all carbon-fuel burners having pulverized fuel ejection nozzles for ejecting carbon fuel into the furnace 11. That is, in this embodiment, all burners 21 belonging to a certain stage are configured as carbon-fuel burners (note that in this case, an ammonia burner is present in another stage).

The carbon fuel burners 21A, 21B, ..., 21B1, 21B2, ... are supplied with carbon fuel from a carbon fuel supply source (not shown). The carbon fuel supply source is connected to carbon fuel main transport pipes 56A, 56B, which branch into multiple carbon fuel branch transport pipes 58A-1, 58A-2, ..., 58B-1, 58B-2, ... for each burner 21A, 21B, ..., 21B1, 21B2, .... In addition, each carbon fuel branch transport pipe 58A-1, 58A-2, ..., 58B-1, 58B-2, ... is provided with a carbon fuel flow meter 62A-1, 62A-2, ..., 62B-1, 62B-2, ... for detecting the flow rate of the transported carbon fuel.

In this embodiment, in step S1, the total flow rate of carbon fuel in each region 40-1, 40-2, . . . is obtained as the index parameter Pi. Specifically, the index parameter acquisition unit 110 acquires the detected values of the carbon fuel flowmeters 62A-1, 62A-2, . . . and 62B-1, 62B-2, . The total flow rate of carbon fuel in each region 40-1, 40-2, . . . is calculated as follows. Specifically, for the region 40-1, the total carbon fuel flow rate is calculated as the sum of the detection values of the two corresponding carbon fuel flowmeters 62A-1 and 62B-1.

The total carbon fuel flow rate calculated in this way is a parameter that correlates with the air ratio in each region. Therefore, by obtaining the total carbon fuel flow rate for a plurality of regions 40-1, 40-2, . ), the air ratio distribution over multiple regions 40-1, 40-2, . . . can be evaluated. Then, the operating parameter Po can be adjusted as described above so that the air ratio distribution approaches uniformity. ).

Next, another embodiment will be described with reference to FIG. 11. FIG. 11 is a schematic diagram of an arrangement layout of burners 21 in a furnace 11 according to another embodiment.

In this embodiment, compared to FIG. 10, among the plurality of carbon fuel branch conveyance pipes 58A-1, 58A-2, . . . Flow control dampers 64A-1, 64A-2, ... and 64B-1 are provided upstream of 62A-1, 62A-2, ... and 62B-1, 62B-2, .... , 64B-2, . . . are provided respectively. The flow control dampers 64A-1, 64A-2, . . . and 64B-1, 64B-2, . . . are dampers whose opening degree can be controlled based on a control signal from the boiler control device 100. , the amount of carbon fuel supplied to the burners 21A1, 21A2, . . . and 21B1, 21B2, . . . can be individually adjusted.

In this embodiment, the opening degrees of the flow control dampers 64A-1, 64A-2, . . . and 64B-1, 64B-2, . . . are used as the operation parameter Po to be adjusted in step S4. be able to. As a result, the opening degrees of the flow control dampers 64A-1, 64A-2, . . . and 64B-1, 64B-2, . . . are determined based on the air ratio distribution evaluated based on the index parameter Pi. By adjusting them individually, the flow rate of carbon fuel to each burner 21 can be adjusted so that the air ratio distribution in each region 40-1, 40-2, . . . approaches uniformity.

In other embodiments, the amount of secondary air supplied to the ammonia burner among the plurality of burners 21 may be adopted as the operation parameter Po to be adjusted in step S4. As a result, by individually adjusting the amount of secondary air supplied to each region 40-1, 40-2, ..., the air ratio distribution in the plurality of regions 40-1, 40-2, ... can be adjusted. It can be made close to uniform.

In other embodiments, the amount of additional air supplied from the AA port 25 may be adopted as the operating parameter Po to be adjusted in step S4. As a result, by individually adjusting the amount of additional air supplied to each region 40-1, 40-2, ..., the air ratio distribution in the plurality of regions 40-1, 40-2, ... can be made uniform. can be approached.

As described above, according to each of the above embodiments, an index parameter Pi for evaluating the air ratio is acquired for each of the regions 40-1, 40-2, .... The air ratio in each of the regions 40-1, 40-2, ... is evaluated based on the index parameter Pi acquired in this way. Based on the air ratio in each of the regions 40-1, 40-2, ... evaluated in this way, a plurality of operation parameters Po correlated with the air ratio are adjusted, so that the air ratio in each of the regions 40-1, 40-2, ... approaches uniformity. This makes it possible to effectively suppress the spatial deviation of the air ratio in each of the regions 40-1, 40-2, ..., and improve the boiler performance.

The contents described in each of the above embodiments can be understood, for example, as follows:

(1) A boiler control device according to one aspect includes:
In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control device for controlling a boiler,
an index parameter acquisition unit for acquiring index parameters for evaluating the air ratio for each of the plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. an operation parameter adjustment amount calculation unit for calculating;
an operation parameter adjustment unit for adjusting at least a portion of the plurality of operation parameters based on the adjustment amount;
Equipped with

According to the aspect (1) above, in a so-called opposed combustion type boiler in which a pair of jet nozzles for jetting carbon fuel or ammonia into a furnace are arranged along the width direction of the furnace, each pair of jet nozzles corresponds to An index parameter for evaluating the air ratio is obtained for each region. The air ratio in each region is evaluated based on the index parameter acquired in this way, and the adjustment amount of the operating parameter is calculated so that the air ratio in each region approaches uniformity. By adjusting the operating parameters that are correlated with the air ratio of each region based on the adjustment amount calculated in this way, it is possible to effectively suppress the spatial deviation of the air ratio in each region and improve the boiler performance.

(2) In another aspect, in the aspect of (1) above,
The operating parameter adjustment amount calculation unit calculates the adjustment amount when an air ratio deviation included in the air ratio distribution in the plurality of regions evaluated based on the index parameter is equal to or greater than a threshold value.

According to the above aspect (2), the need for adjustment of the operation parameters is determined based on whether the air ratio deviation included in the air ratio distribution evaluated from the index parameter is equal to or greater than a threshold. If the air ratio deviation is equal to or greater than the threshold, it is determined that the spatial deviation of the air ratio is large and therefore adjustment of the operation parameters is necessary, and the amount of adjustment of the operation parameters is calculated.

(3) In another aspect, in the aspect (2) above,
The operation parameter adjustment amount calculation unit calculates the adjustment amount so that a maximum value included in the air ratio distribution decreases.

According to the aspect (3) above, the operating parameters are adjusted so that the maximum value included in the air ratio distribution is reduced. Thereby, the air ratio distribution, which has spatial deviation, can be effectively brought closer to uniformity, and the boiler performance can be improved.

(4) In another aspect, in the aspect (2) or (3) above,
The operation parameter adjustment amount calculation unit calculates the adjustment amount so that a minimum value included in the air ratio distribution increases.

According to the aspect (4) above, the operating parameters are adjusted so that the minimum value included in the air ratio distribution increases. Thereby, the air ratio distribution, which has spatial deviation, can be effectively brought closer to uniformity, and the boiler performance can be improved.

(5) In another aspect, in the aspect (1) or (2) above,
The operation parameter adjustment amount calculation unit calculates the adjustment amount of the operation parameter by converting the necessary adjustment amount of the index parameter based on correlation data that defines a correlation between the index parameter and the operation parameter.

According to the aspect (5) above, the adjustment amount of the operation parameter can be suitably calculated from the required adjustment amount of the index parameter using the correlation data that defines the correlation between the index parameter and the operation parameter.

(6) In another embodiment, in the above embodiment (5),
The correlation data is prepared for each operating condition of the boiler.

According to the aspect (6) above, by preparing correlation data for each operating condition, the amount of adjustment of operating parameters to make the air ratio distribution closer to uniformity can be calculated with higher accuracy according to the operating state of the boiler. can.

(7) In another aspect, in the aspect (1) or (2) above,
The operating parameter adjustment amount calculation unit calculates the adjustment amount of the operating parameter based on optimal value data that defines an optimal value of the operating parameter corresponding to each of the plurality of regions for each operating condition of the boiler. .

According to the aspect (7) above, the air ratio distribution for each area can be effectively adjusted by adjusting the operating parameters to the optimum values specified in the optimum value data according to the operating conditions of the boiler. It can be made close to uniform.

(8) In another aspect, in the aspect (1) or (2) above,
The operation parameter adjustment amount calculation unit calculates the adjustment amount using a machine learning model for predicting the adjustment amount of the operation parameter based on the operating conditions of the boiler or the index parameter.

According to the aspect (8) above, by adjusting the operating parameters using the adjustment amount predicted using the machine learning model, the air ratio distribution for each region can be effectively made uniform.

(9) In another aspect, in any one of the above (1) to (8),
The index parameter is a measured value of NOx concentration or O2 concentration in the furnace.

According to the aspect (9) above, by using the NOx concentration or O2 concentration as the index parameter, the air ratio for each region can be suitably evaluated.

(10) In another aspect, in any one of the above (1) to (8),
The index parameter is the total supply of the carbon fuel per region.

According to the above aspect (10), the total amount of carbon fuel supplied to each region can be used as an index parameter, making it possible to appropriately evaluate the air ratio for each region.

(11) In another aspect, in any one of the above (1) to (10),
The operating parameter is the amount of ammonia supplied to each of the plurality of regions.

According to the aspect (11) above, by adjusting the amount of ammonia supplied to each region as an operating parameter, the air ratio in each region can be brought close to uniformity, and boiler performance can be effectively improved.

(12) In another aspect, in any one of the above (1) to (10),
The operating parameter is a supply of the carbon fuel to each of the plurality of regions.

According to the aspect (12) above, by adjusting the amount of carbon fuel supplied to each region as an operating parameter, the air ratio in each region can be brought closer to uniformity, and the boiler performance can be effectively improved.

(13) In another aspect, in any one of the above (1) to (10),
The operating parameter is the amount of air supplied to each of the plurality of regions.

According to the aspect (13) above, by adjusting the amount of air supplied to each region as an operating parameter, the air ratio in each region can be made uniform, and the boiler performance can be effectively improved.

(14) In another aspect, in any one of the above (1) to (13),
The carbon fuel ejected from the carbon fuel injection nozzle and the ammonia ejected from the ammonia injection nozzle are burned in mutually independent burners.

According to the aspect (14) above, in a boiler in which carbon fuel and ammonia are burned in mutually independent burners, good exhaust gas performance is achieved by improving the spatial deviation of the air ratio in the furnace during ammonia co-firing. It can be achieved.

(15) A boiler control method according to one aspect includes:
In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control method for controlling a boiler, comprising:
obtaining index parameters for evaluating air ratios for each of a plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. The process of calculating,
adjusting at least a portion of the plurality of operating parameters based on the adjustment amount;
Equipped with

According to the aspect (15) above, in a so-called opposed combustion type boiler in which a pair of jet nozzles for jetting carbon fuel or ammonia into the furnace are arranged along the width direction of the furnace, each pair of jet nozzles corresponds to An index parameter for evaluating the air ratio is obtained for each region. The air ratio in each region is evaluated based on the index parameter acquired in this way, and the adjustment amount of the operating parameter is calculated so that the air ratio in each region approaches uniformity. By adjusting the operating parameters that are correlated with the air ratio of each region based on the adjustment amount calculated in this way, it is possible to effectively suppress the spatial deviation of the air ratio in each region and improve the boiler performance.

(16) The boiler control program according to one aspect is:
In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control program for controlling a boiler,
to the computer,
obtaining index parameters for evaluating air ratios for each of a plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. The process of calculating,
adjusting at least a portion of the plurality of operating parameters based on the adjustment amount;
and is executable.

According to the aspect (16) above, in a so-called opposed combustion type boiler in which a pair of jet nozzles for jetting carbon fuel or ammonia into the furnace are arranged along the width direction of the furnace, each pair of jet nozzles corresponds to An index parameter for evaluating the air ratio is obtained for each region. The air ratio in each region is evaluated based on the index parameter acquired in this way, and the adjustment amount of the operating parameter is calculated so that the air ratio in each region approaches uniformity. By adjusting the operating parameters that are correlated with the air ratio of each region based on the adjustment amount calculated in this way, it is possible to effectively suppress the spatial deviation of the air ratio in each region and improve the boiler performance.

REFERENCE SIGNS LIST 10 Boiler 11 Furnace 12 Combustion gas passage 13 Flue 17 Furnace wall 20 Combustion device 21 Burner 25 Additional air port 50 Ammonia main transport pipe 52 Ammonia branch transport pipe 54 Flow control valve 56 Carbon fuel main transport pipe 58 Carbon fuel branch transport pipe 60 Concentration measurement unit 62 Carbon fuel flow meter 64 Flow adjustment damper 70 Correlation data 80 Optimum value data 100 Boiler control device 110 Index parameter acquisition unit 120 Operation parameter adjustment amount calculation unit 130 Operation parameter adjustment unit

Claims (16)

In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control device for controlling a boiler,
an index parameter acquisition unit for acquiring index parameters for evaluating the air ratio for each of the plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. an operation parameter adjustment amount calculation unit for calculating;
an operation parameter adjustment unit for adjusting at least a portion of the plurality of operation parameters based on the adjustment amount;
A boiler control device comprising: 1 . The operating parameter adjustment amount calculation unit calculates the adjustment amount when an air ratio deviation included in an air ratio distribution in the plurality of regions evaluated based on the index parameter is equal to or greater than a threshold value. Boiler control device described in. The boiler control device according to claim 2, wherein the operation parameter adjustment amount calculation unit calculates the adjustment amount so that a maximum value included in the air ratio distribution decreases. The boiler control device according to claim 2, wherein the operation parameter adjustment amount calculation unit calculates the adjustment amount so that a minimum value included in the air ratio distribution increases. The operation parameter adjustment amount calculation unit calculates the adjustment amount of the operation parameter by converting the required adjustment amount of the index parameter based on correlation data that defines a correlation between the index parameter and the operation parameter. The boiler control device according to claim 1 or 2. The boiler control device according to claim 5, wherein the correlation data is prepared for each operating condition of the boiler. The operating parameter adjustment amount calculation unit calculates the adjustment amount of the operating parameter based on optimal value data that defines an optimal value of the operating parameter corresponding to each of the plurality of regions for each operating condition of the boiler. , The boiler control device according to claim 1 or 2. The operating parameter adjustment amount calculation unit calculates the adjustment amount using a machine learning model for predicting the adjustment amount of the operating parameter based on the operating conditions of the boiler or the index parameter. 2. The boiler control device according to 2. The boiler control device according to claim 1 or 2, wherein the index parameter is a measured value of NOx concentration or O2 concentration in the furnace. The boiler control device according to claim 1 or 2, wherein the index parameter is a total supply amount of the carbon fuel for each region. The boiler control device according to claim 1 or 2, wherein the operating parameter is the amount of ammonia supplied to each of the plurality of regions. The boiler control device according to claim 1 or 2, wherein the operating parameter is the amount of the carbon fuel supplied to each of the plurality of regions. The boiler control device according to claim 1 or 2, wherein the operating parameter is an amount of air supplied to each of the plurality of regions. The boiler control device according to claim 1 or 2, wherein the carbon fuel ejected from the carbon fuel injection nozzle and the ammonia ejected from the ammonia injection nozzle are burned in mutually independent burners. In a boiler that burns carbon fuel and ammonia in a furnace,
a carbon fuel injection nozzle for injecting the carbon fuel into the furnace;
an ammonia spouting nozzle for spouting the ammonia into the furnace;
Equipped with
A plurality of pairs of jet nozzles including at least one of the carbon fuel jet nozzle or the ammonia jet nozzle and arranged on the wall surface of the furnace so as to face each other are arranged along the furnace width direction of the furnace. A boiler control method for controlling a boiler, comprising:
obtaining index parameters for evaluating air ratios for each of a plurality of regions corresponding to the plurality of pairs of jet nozzles;
Adjusting amounts for at least some of the plurality of operating parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity. The process of calculating,
adjusting at least a portion of the plurality of operating parameters based on the adjustment amount;
A boiler control method comprising: In a boiler that burns carbon fuel and ammonia in a furnace,
a carbonaceous fuel injection nozzle for injecting the carbonaceous fuel into the furnace;
an ammonia injection nozzle for injecting the ammonia into the furnace;
Equipped with
A boiler control program for controlling a boiler in which a plurality of pairs of ejection nozzles, each of which includes at least one of the carbon fuel ejection nozzle or the ammonia ejection nozzle and is arranged on a wall surface of the furnace so as to face each other, are arranged along a furnace width direction of the furnace,
On the computer,
acquiring an index parameter for evaluating an air ratio for each of a plurality of regions corresponding to the plurality of pairs of ejection nozzles;
calculating adjustment amounts for at least a portion of a plurality of operation parameters having a correlation with the air ratio in each of the plurality of regions so that the air ratio for each of the plurality of regions evaluated based on the index parameter approaches uniformity;
adjusting at least a portion of the plurality of operating parameters based on the adjustment amount;
A boiler control program capable of executing the above.

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