JP7533754B2 - Combustion equipment and boilers - Google Patents

Description

The present disclosure relates to a combustion device and a boiler. This application claims the benefit of priority based on Japanese Patent Application No. 2021-025118 filed on February 19, 2021, the contents of which are incorporated herein by reference.

Among the burners installed in furnaces such as boilers, there are burners that have an ammonia injection nozzle that injects ammonia as fuel. By using ammonia as fuel, carbon dioxide emissions can be reduced. For example, Patent Document 1 discloses a burner that mixes pulverized coal and ammonia as fuel.

JP 2019-086189 A

In a burner having an ammonia injection nozzle, a flame is formed in front of the burner by injecting ammonia from an injection port provided at the tip of the ammonia injection nozzle. The tip of the ammonia injection nozzle is exposed to an atmosphere containing ammonia and at high temperatures, and is therefore prone to nitriding. Therefore, in order to suppress the decrease in toughness that accompanies the nitriding of the tip of the ammonia injection nozzle, it is desirable to suppress the nitriding of the ammonia injection nozzle.

The object of the present disclosure is to provide a combustion device and boiler capable of suppressing nitridation of ammonia injection nozzles.

In order to solve the above problems, the combustion device disclosed herein comprises a burner having an ammonia injection nozzle with an injection port at its tip that faces the internal space of the furnace, an adjustment mechanism that adjusts the temperature of the tip, and a control device that controls the operation of the adjustment mechanism so that the temperature of the tip is below a reference temperature , and the adjustment mechanism includes a mechanism for adjusting the opening area of the injection port .
In order to solve the above problems, the combustion device disclosed herein comprises a burner having an ammonia injection nozzle with an injection port at its tip that faces the internal space of the furnace, an air pipe arranged coaxially with the ammonia injection nozzle and surrounding the ammonia injection nozzle, an adjustment mechanism for adjusting the temperature of the tip, and a control device for controlling the operation of the adjustment mechanism so that the temperature of the tip is equal to or lower than a reference temperature, and the adjustment mechanism includes a mechanism for adjusting the flow rate of air in the air pipe.

The adjustment mechanism may include a mechanism for adjusting the flow rate of ammonia in the ammonia injection nozzle.

The adjustment mechanism may include a mechanism for adjusting the distance between the nozzle and the interior space.

In order to solve the above problems, the boiler disclosed herein is equipped with the above-mentioned combustion device.

According to the present disclosure, nitridation of ammonia injection nozzles can be suppressed.

FIG. 1 is a schematic diagram showing a boiler according to the present embodiment. FIG. 2 is a schematic diagram showing the combustion device according to this embodiment. FIG. 3 is a flowchart showing an example of the flow of processing performed by the control device according to the present embodiment. FIG. 4 is a schematic diagram showing a combustion apparatus according to a first modified example. FIG. 5 is a schematic diagram showing a state in which the tip temperature is higher in the combustion device according to the first modified example than in the example of FIG. FIG. 6 is a schematic diagram showing a combustion apparatus according to a second modified example. FIG. 7 is a schematic diagram showing a state in which the tip temperature is higher in the combustion device according to the second modified example than in the example of FIG. FIG. 8 is a schematic diagram showing a combustion apparatus according to a third modified example.

Below, an embodiment of the present disclosure will be described with reference to the attached drawings. The dimensions, materials, and other specific values shown in the embodiments are merely examples for ease of understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid duplicated explanations, and elements not directly related to the present disclosure are not illustrated.

Figure 1 is a schematic diagram showing a boiler 1 according to this embodiment. As shown in Figure 1, the boiler 1 includes a furnace 2, a flue 3, and a burner 4.

The furnace 2 is a furnace that burns fuel to generate combustion heat. Below, an example in which ammonia and pulverized coal are used as fuel in the furnace 2 will be mainly described. By using ammonia and pulverized coal as fuel, carbon dioxide emissions are reduced. However, as described below, the fuel used in the furnace 2 is not limited to this example.

The furnace 2 has a cylindrical shape (e.g., a rectangular cylindrical shape) extending vertically. In the furnace 2, high-temperature combustion gas is generated by burning fuel. An exhaust port 2a is provided at the bottom of the furnace 2 to discharge ash generated by the combustion of the fuel to the outside.

The flue 3 is a passage that guides the combustion gas generated in the furnace 2 to the outside as exhaust gas. The flue 3 is connected to the upper part of the furnace 2. The flue 3 has a horizontal flue 3a and a rear flue 3b. The horizontal flue 3a extends horizontally from the upper part of the furnace 2. The rear flue 3b extends downward from the end of the horizontal flue 3a.

The boiler 1 is equipped with a superheater (not shown) that is installed on the top of the furnace 2, etc. In the superheater, heat exchange takes place between the combustion heat generated in the furnace 2 and water, thereby generating steam. The boiler 1 may also be equipped with various devices (e.g., a reheater, a coal economizer, or an air preheater) that are not shown in FIG. 1.

The burners 4 are provided on the wall at the bottom of the furnace 2. A plurality of burners 4 are provided in the furnace 2 at intervals in the circumferential direction of the furnace 2. Although not shown in FIG. 1, the plurality of burners 4 are also provided at intervals in the extension direction (up and down direction) of the furnace 2. The burners 4 inject ammonia and pulverized coal as fuel into the furnace 2. The fuel injected from the burners 4 is combusted to form a flame F in the furnace 2. The furnace 2 is provided with an ignition device (not shown) that ignites the fuel injected from the burners 4.

Figure 2 is a schematic diagram showing the combustion device 100 according to this embodiment. As shown in Figure 2, the combustion device 100 includes a burner 4, an air supply unit 5, an ammonia tank 6, an adjustment mechanism 7 (specifically, a mechanism including a flow rate adjustment valve 71), a temperature sensor 8, and a control device 9.

The burner 4 is attached to the wall of the furnace 2 outside the furnace 2. The burner 4 has an ammonia injection nozzle 41, an air injection nozzle 42, and a pulverized coal injection nozzle 43. The ammonia injection nozzle 41 is a nozzle that injects ammonia. The air injection nozzle 42 is a nozzle that injects air for combustion. The pulverized coal injection nozzle 43 is a nozzle that injects pulverized coal.

The ammonia injection nozzle 41, the air injection nozzle 42, and the pulverized coal injection nozzle 43 have a cylindrical shape. The air injection nozzle 42 is arranged coaxially with the ammonia injection nozzle 41 so as to surround the ammonia injection nozzle 41. The pulverized coal injection nozzle 43 is arranged coaxially with the air injection nozzle 42 so as to surround the air injection nozzle 42. A triple cylindrical structure is formed by the ammonia injection nozzle 41, the air injection nozzle 42, and the pulverized coal injection nozzle 43. The central axes of the ammonia injection nozzle 41, the air injection nozzle 42, and the pulverized coal injection nozzle 43 intersect with the wall of the furnace 2 (specifically, are approximately perpendicular).

Hereinafter, the radial direction of the burner 4, the axial direction of the burner 4, and the circumferential direction of the burner 4 will also be simply referred to as the radial direction, the axial direction, and the circumferential direction. The furnace 2 side of the burner 4 (the right side in FIG. 2) will be referred to as the leading end side, and the opposite side of the burner 4 to the furnace 2 side (the left side in FIG. 2) will be referred to as the trailing end side.

The ammonia injection nozzle 41 includes a main body 41a, a supply port 41b, and an injection port 41c. The main body 41a has a cylindrical shape. The main body 41a extends on the central axis of the burner 4. The thickness, inner diameter, and outer diameter of the main body 41a are approximately constant regardless of the axial position. However, the thickness, inner diameter, and outer diameter of the main body 41a may change depending on the axial position. A supply port 41b, which is an opening, is provided at the rear end of the main body 41a. The supply port 41b is connected to the ammonia tank 6. A injection port 41c, which is an opening, is provided at the tip of the main body 41a. The injection port 41c faces the internal space of the furnace 2. In other words, the injection port 41c faces the internal space of the furnace 2.

Ammonia is supplied from the ammonia tank 6 into the main body 41a through the supply port 41b. As shown by the arrow A1, the ammonia supplied into the main body 41a flows inside the main body 41a. The ammonia that has passed through the main body 41a is injected from the injection port 41c toward the internal space of the furnace 2. In this way, the ammonia injection nozzle 41 is provided toward the internal space of the furnace 2.

The air injection nozzle 42 includes a main body 42a and an injection port 42b. The main body 42a has a cylindrical shape. The main body 42a is arranged coaxially with the main body 41a of the ammonia injection nozzle 41 so as to surround the main body 41a. The main body 42a has a shape that tapers toward the tip side. A supply port (not shown) is provided at the rear of the main body 42a (i.e., the rear end portion).

The supply port of the air injection nozzle 42 is connected to an air supply source (not shown). For example, the supply port of the air injection nozzle 42 is exposed to the atmosphere as the air supply source. An opening, injection port 42b, is provided at the tip of the main body 42a. The tip of the main body 41a of the ammonia injection nozzle 41 is located radially inside the tip of the main body 42a. The injection port 42b is an annular opening between the tip of the main body 42a and the tip of the main body 41a of the ammonia injection nozzle 41. The injection port 42b faces the internal space of the furnace 2. In other words, the injection port 42b faces the internal space of the furnace 2.

Air is supplied from an air supply source (e.g., the atmosphere) into the body 42a through a supply port (not shown). As shown by arrow A2, the air supplied into the body 42a flows through the space between the inner periphery of the body 42a and the outer periphery of the body 41a of the ammonia injection nozzle 41. The air that passes through the body 42a is injected from the injection port 42b toward the internal space of the furnace 2. In this way, the air injection nozzle 42 is provided toward the internal space of the furnace 2.

The pulverized coal injection nozzle 43 includes a main body 43a and an injection port 43b. The main body 43a has a cylindrical shape. The main body 43a is arranged coaxially with the main body 42a of the air injection nozzle 42 so as to surround the main body 42a. The main body 43a has a shape that tapers toward the tip side. A supply port (not shown) is provided at the rear of the main body 43a (i.e., the rear end portion).

The supply port of the pulverized coal injection nozzle 43 is connected to a pulverized coal supply source (not shown). An injection port 43b, which is an opening, is provided at the tip of the main body 43a. The axial position of the tip of the main body 43a approximately coincides with the axial position of the tip of the main body 42a of the air injection nozzle 42. The injection port 43b is an annular opening between the tip of the main body 43a and the tip of the main body 42a of the air injection nozzle 42. The injection port 43b faces the internal space of the furnace 2. In other words, the injection port 43b faces the internal space of the furnace 2.

Pulverized coal is supplied into the main body 43a from a pulverized coal supply source through a supply port (not shown) together with air for transporting the pulverized coal. As shown by arrow A3, the pulverized coal supplied into the main body 43a flows together with the air in the space between the inner periphery of the main body 43a and the outer periphery of the main body 42a of the air injection nozzle 42. The pulverized coal that passes through the main body 43a is injected from the injection port 43b toward the internal space of the furnace 2. In this way, the pulverized coal injection nozzle 43 is provided toward the internal space of the furnace 2.

The air supply unit 5 supplies combustion air from the radial outside to the flame formed by the burner 4 (see flame F in FIG. 1). The air supply unit 5 is arranged to cover the area between the tip of the burner 4 and the furnace 2. The air supply unit 5 has a flow path 51 through which air flows. The flow path 51 is formed in a cylindrical shape coaxial with the burner 4. The flow path 51 is connected to an air supply source (not shown). An injection port 52 is formed at the end of the flow path 51 on the furnace 2 side.

As shown by arrow A4, air supplied from an air supply source to air supply unit 5 passes through flow path 51 and is sprayed from nozzle 52 toward the internal space of furnace 2. Jet port 52 faces the internal space of furnace 2. In other words, jet port 52 faces toward the internal space of furnace 2. In this way, air supply unit 5 is provided facing the internal space of furnace 2. Air sprayed from nozzle 52 of air supply unit 5 advances toward the internal space of furnace 2 while swirling in the circumferential direction.

The adjustment mechanism 7 is a mechanism for adjusting the temperature (hereinafter also referred to as the tip temperature) of the tip of the ammonia injection nozzle 41. The tip of the ammonia injection nozzle 41 is a portion of the ammonia injection nozzle 41 near the injection port 41c (for example, a portion within a predetermined distance axially rearward from the injection port 41c).

In this embodiment, the adjustment mechanism 7 adjusts the flow rate of ammonia in the ammonia injection nozzle 41 (hereinafter also referred to as the ammonia flow rate) to adjust the tip temperature of the ammonia injection nozzle 41. The adjustment mechanism 7 has a flow rate adjustment valve 71.

The flow rate control valve 71 adjusts the flow rate of ammonia supplied from the ammonia tank 6 to the ammonia injection nozzle 41. The flow rate control valve 71 is provided in a flow path connecting the ammonia tank 6 and the supply port 41b of the ammonia injection nozzle 41. The flow rate of ammonia supplied from the ammonia tank 6 to the ammonia injection nozzle 41 is adjusted by adjusting the opening of the flow rate control valve 71. This adjusts the flow rate of ammonia at the ammonia injection nozzle 41 (i.e., the ammonia flow rate). Specifically, the greater the opening of the flow rate control valve 71, the greater the ammonia flow rate.

Ammonia is stored in liquid form in the ammonia tank 6. The ammonia stored in the ammonia tank 6 is vaporized by a vaporizer. The vaporized ammonia is supplied to the ammonia injection nozzle 41 through a flow control valve 71.

Here, the tip of the ammonia injection nozzle 41 is cooled by the ammonia flowing through the ammonia injection nozzle 41. The greater the ammonia flow rate, the greater the cooling capacity of the ammonia flowing through the ammonia injection nozzle 41 (i.e., the capacity to cool the tip of the ammonia injection nozzle 41). Therefore, the adjustment mechanism 7 can adjust the tip temperature of the ammonia injection nozzle 41 by adjusting the ammonia flow rate.

The temperature sensor 8 detects the temperature of the tip of the ammonia injection nozzle 41. The temperature sensor 8 is provided at the tip of the ammonia injection nozzle 41 and detects the temperature at the installation position. The temperature sensor 8 may be provided on the outer periphery or inner periphery of the tip of the ammonia injection nozzle 41. Various types of sensors that can be used in high temperature environments can be used as the temperature sensor 8. The detection result by the temperature sensor 8 is output to the control device 9.

The control device 9 includes a central processing unit (CPU), a ROM in which programs and the like are stored, a RAM as a work area, and the like, and controls the entire combustion device 100. In particular, the control device 9 controls the operation of the adjustment mechanism 7. Specifically, the control device 9 can adjust the ammonia flow rate and adjust the tip temperature of the ammonia injection nozzle 41 by controlling the opening degree of the flow rate adjustment valve 71 of the adjustment mechanism 7.

Figure 3 is a flowchart showing an example of the flow of processing performed by the control device 9 according to this embodiment. The processing flow shown in Figure 3 is executed continuously (i.e. repeatedly) to precisely control the tip temperature of the ammonia injection nozzle 41, for example.

3 starts, in step S101, the control device 9 acquires the tip temperature of the ammonia injection nozzle 41. For example, the control device 9 acquires the tip temperature of the ammonia injection nozzle 41 from the temperature sensor 8.

By acquiring the detection result of the temperature sensor 8 as the tip temperature of the ammonia injection nozzle 41, the tip temperature of the ammonia injection nozzle 41 can be acquired with high accuracy. However, the control device 9 may acquire information other than the detection result of the temperature sensor 8 (for example, the temperature of the atmosphere around the tip of the ammonia injection nozzle 41) as information for estimating the tip temperature of the ammonia injection nozzle 41.

After step S101, in step S102, the control device 9 sets the target opening degree of the flow control valve 71 to an opening degree such that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than a reference temperature. As described later, the opening degree of the flow control valve 71 is controlled to the target opening degree.

Here, the tip of the ammonia injection nozzle 41 is exposed to an atmosphere in which ammonia is present and at high temperatures, and is therefore susceptible to nitridation. The tip of the ammonia injection nozzle 41 is heated by radiant heat from the internal space of the furnace 2 in which the flame F is formed. Nitridation of the tip of the ammonia injection nozzle 41 is more likely to occur as the tip temperature increases. The reference temperature is a temperature below the lower limit of the nitriding temperature range, which is a temperature range in which nitridation of the tip of the ammonia injection nozzle 41 is likely to occur. In other words, when the tip temperature of the ammonia injection nozzle 41 becomes below the reference temperature, nitridation of the tip of the ammonia injection nozzle 41 is suppressed.

In step S102, the control device 9 sets a target opening degree of the flow control valve 71 based on the tip temperature of the ammonia injection nozzle 41. The higher the tip temperature of the ammonia injection nozzle 41, the larger the opening degree set by the control device 9 as the target opening degree. As a result, the higher the tip temperature of the ammonia injection nozzle 41, the larger the ammonia flow rate, and the higher the cooling capacity of the ammonia flowing through the ammonia injection nozzle 41. Therefore, the tip temperature of the ammonia injection nozzle 41 is appropriately kept below the reference temperature.

After step S102, in step S103, the control device 9 controls the flow rate control valve 71 so that the opening degree of the flow rate control valve 71 becomes the target opening degree, and the processing flow shown in Figure 3 ends.

As described above, in the combustion device 100 according to this embodiment, the adjustment mechanism 7 adjusts the ammonia flow rate. This appropriately adjusts the tip temperature of the ammonia injection nozzle 41. The control device 9 controls the operation of the adjustment mechanism 7 so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature. This makes it possible to suppress the tip temperature of the ammonia injection nozzle 41 from rising to the nitriding temperature range where nitriding is likely to occur. Therefore, nitriding of the ammonia injection nozzle 41 is suppressed. Therefore, the decrease in toughness associated with nitriding of the ammonia injection nozzle 41 is suppressed. This makes it possible to suppress, for example, the decrease in combustion stability due to thinning of the tip of the ammonia injection nozzle 41. In addition, for example, the frequency of repairs of the ammonia injection nozzle 41 can be reduced.

In particular, the control device 9 controls the operation of the adjustment mechanism 7 so that the higher the tip temperature of the ammonia injection nozzle 41, the larger the ammonia flow rate (i.e., so that the tip of the ammonia injection nozzle 41 is more easily cooled). This allows the tip temperature of the ammonia injection nozzle 41 to be appropriately kept below the reference temperature.

Since the main purpose of the ammonia injected from the ammonia injection nozzle 41 is to be used as fuel for the burner 4, the ammonia flow rate is controlled with a priority on ensuring the flow rate required for fuel. For example, if the ammonia flow rate required to ensure the cooling capacity of the ammonia flowing through the ammonia injection nozzle 41 (i.e., the ammonia flow rate required to keep the tip temperature of the ammonia injection nozzle 41 at or below the reference temperature) is smaller than the flow rate required for fuel, the control device 9 controls the operation of the adjustment mechanism 7 so that the ammonia flow rate becomes the flow rate required for fuel.

In the above, an example has been described in which the adjustment mechanism 7 adjusts the tip temperature of the ammonia injection nozzle 41 by adjusting the ammonia flow rate. However, the adjustment mechanism 7 is not limited to the above example as long as it has the function of adjusting the tip temperature of the ammonia injection nozzle 41. Below, a modified example is described in which adjustment mechanisms 7A, 7B, and 7C different from the adjustment mechanism 7 of the combustion device 100 are used.

Figure 4 is a schematic diagram showing a combustion device 100A according to a first modified example. As shown in Figure 4, the combustion device 100A is an example in which the adjustment mechanism 7 in the above-mentioned combustion device 100 is replaced with an adjustment mechanism 7A.

The adjustment mechanism 7A adjusts the tip temperature of the ammonia injection nozzle 41 by adjusting the distance between the injection port 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2. The adjustment mechanism 7A has a drive device 71A.

The driving device 71A moves the main body 41a of the ammonia injection nozzle 41 in the axial direction. For example, the driving device 71A includes a mechanism for guiding the axial movement of the main body 41a of the ammonia injection nozzle 41 and a device for generating power (for example, a motor, etc.). The driving device 71A can move the main body 41a in the axial direction by transmitting power to the rear part of the main body 41a of the ammonia injection nozzle 41.

The adjustment mechanism 7A can adjust the separation distance between the nozzle 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2 by axially moving the body 41a of the ammonia injection nozzle 41 using the drive device 71A.

As described above, the tip of the ammonia injection nozzle 41 is heated by radiant heat from the internal space of the furnace 2 where the flame F is formed. The longer the separation distance between the injection port 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2 (i.e., the farther the injection port 41c is from the internal space of the furnace 2), the less likely the tip of the ammonia injection nozzle 41 is to be heated by radiant heat from the internal space of the furnace 2. Therefore, the adjustment mechanism 7A can adjust the separation distance between the injection port 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2 to adjust the tip temperature of the ammonia injection nozzle 41.

The control device 9 controls the operation of the adjustment mechanism 7A so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature, as in the combustion device 100 described above. Specifically, the control device 9 controls the operation of the drive device 71A so that the body 41a of the ammonia injection nozzle 41 moves in a direction toward the outside of the furnace 2 as the tip temperature of the ammonia injection nozzle 41 increases. As a result, the control device 9 can control the operation of the adjustment mechanism 7A so that the injection port 41c of the ammonia injection nozzle 41 moves in a direction toward the outside of the furnace 2 as the tip temperature of the ammonia injection nozzle 41 increases. In other words, the control device 9 can control the operation of the adjustment mechanism 7A so that the separation distance between the injection port 41c and the internal space of the furnace 2 increases as the tip temperature of the ammonia injection nozzle 41 increases. Therefore, the degree to which the tip of the ammonia injection nozzle 41 is heated by radiant heat from the furnace 2 decreases, and the tip temperature of the ammonia injection nozzle 41 is appropriately kept equal to or lower than the reference temperature.

Figure 5 is a schematic diagram showing a state in which the tip temperature is higher than that in the example of Figure 4 in the combustion device 100A according to the first modified example. In the example of Figure 5, the tip temperature is higher than that in the example of Figure 4. Therefore, the main body 41a of the ammonia injection nozzle 41 moves in a direction toward the outside of the furnace 2 compared to the example of Figure 4. As a result, the injection port 41c moves in a direction toward the outside of the furnace 2 compared to the example of Figure 4. Specifically, the axial position of the injection port 41c is closer to the furnace 2 than the axial positions of the injection ports 42b and 43b in the example of Figure 4, while in the example of Figure 5, it is approximately the same as the axial positions of the injection ports 42b and 43b. Therefore, the degree to which the tip of the ammonia injection nozzle 41 is heated by radiant heat from the furnace 2 is reduced.

As described above, in the combustion device 100A according to the first modified example, the adjustment mechanism 7A adjusts the separation distance between the injection port 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2. This allows the tip temperature of the ammonia injection nozzle 41 to be appropriately adjusted. The control device 9 controls the operation of the adjustment mechanism 7A so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature. This suppresses nitridation of the ammonia injection nozzle 41, as in the combustion device 100 described above.

In particular, the control device 9 controls the operation of the adjustment mechanism 7A so that the higher the tip temperature of the ammonia injection nozzle 41, the more the injection port 41c of the ammonia injection nozzle 41 moves in a direction toward the outside of the furnace 2 (i.e., so that the tip of the ammonia injection nozzle 41 becomes less likely to be heated). This appropriately achieves the temperature of the tip of the ammonia injection nozzle 41 being kept below the reference temperature.

In the above, an example has been described in which the adjustment mechanism 7A for adjusting the separation distance between the injection port 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2 has a drive device 71A and moves the main body 41a of the ammonia injection nozzle 41 in the axial direction by the drive device 71A. However, the adjustment mechanism 7A is not limited to the above example as long as it has the function of adjusting the separation distance between the injection port 41c of the ammonia injection nozzle 41 and the internal space of the furnace 2. For example, the main body 41a of the ammonia injection nozzle 41 can be extended and retracted in the axial direction, and the adjustment mechanism 7A may adjust the separation distance between the injection port 41c and the internal space of the furnace 2 by extending and retracting the main body 41a in the axial direction by the drive device 71A.

Figure 6 is a schematic diagram showing a combustion device 100B according to a second modified example. As shown in Figure 6, the combustion device 100B is an example in which the adjustment mechanism 7 in the above-mentioned combustion device 100 is replaced with an adjustment mechanism 7B.

The adjustment mechanism 7B adjusts the tip temperature of the ammonia injection nozzle 41 by adjusting the opening area of the injection port 41c of the ammonia injection nozzle 41. The adjustment mechanism 7B has a drive device 71B.

In the combustion device 100B according to the second modified example, a variable portion 41d is provided at the tip of the ammonia injection nozzle 41. The variable portion 41d can adjust the opening area of the injection port 41c by deforming. For example, the variable portion 41d includes multiple members spaced apart in the circumferential direction, and can be deformed to assume an inclined position in which the tip of each member is located radially inward from the rear end. For example, a structure similar to that of a convergence-divergence nozzle can be adopted as such a variable portion 41d.

The driving device 71B deforms the variable portion 41d of the ammonia injection nozzle 41. For example, the driving device 71B is provided at the rear end of the variable portion 41d and includes a device that generates power (for example, a motor, etc.). The driving device 71B can change the attitude of the variable portion 41d by rotating the variable portion 41d around the rear end of the variable portion 41d.

The adjustment mechanism 7B can adjust the opening area of the injection port 41c of the ammonia injection nozzle 41 by deforming the variable portion 41d of the ammonia injection nozzle 41 using the drive device 71B.

As described above, the tip of the ammonia injection nozzle 41 is cooled by the ammonia flowing through the ammonia injection nozzle 41. The smaller the opening area of the injection port 41c of the ammonia injection nozzle 41, the higher the injection speed of the ammonia injected from the ammonia injection nozzle 41. Therefore, the cooling capacity of the ammonia flowing near the tip of the ammonia injection nozzle 41 (i.e., the capacity to cool the tip of the ammonia injection nozzle 41) is increased. Therefore, the adjustment mechanism 7B can adjust the tip temperature of the ammonia injection nozzle 41 by adjusting the opening area of the injection port 41c of the ammonia injection nozzle 41.

The control device 9 controls the operation of the adjustment mechanism 7B so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature, as in the combustion device 100 described above. Specifically, the control device 9 controls the operation of the drive device 71B so that the radial position of the tip of the variable part 41d moves radially inward as the tip temperature of the ammonia injection nozzle 41 increases. As a result, the control device 9 can control the operation of the adjustment mechanism 7B so that the opening area of the injection port 41c of the ammonia injection nozzle 41 decreases as the tip temperature of the ammonia injection nozzle 41 increases. Therefore, the injection speed of the ammonia injected from the ammonia injection nozzle 41 increases, and the cooling capacity of the ammonia flowing near the tip of the ammonia injection nozzle 41 increases, so that the tip temperature of the ammonia injection nozzle 41 is appropriately kept equal to or lower than the reference temperature.

Figure 7 is a schematic diagram showing a state in which the tip temperature is higher in the combustion device 100B according to the second modified example compared to the example of Figure 6. In the example of Figure 6, the variable part 41d of the ammonia injection nozzle 41 has a cylindrical shape extending in the axial direction of the burner 4. In the example of Figure 7, the tip temperature is higher compared to the example of Figure 6. Therefore, the variable part 41d is deformed so that the radial position of the tip of the variable part 41d moves radially inward. As a result, the shape of the variable part 41d becomes tapered toward the tip side (in the example of Figure 7, a truncated cone shape). Therefore, the opening area of the injection port 41c of the ammonia injection nozzle 41 becomes smaller, and the injection speed of ammonia becomes higher.

As described above, in the combustion device 100B according to the second modified example, the adjustment mechanism 7B adjusts the opening area of the injection port 41c of the ammonia injection nozzle 41. This allows the tip temperature of the ammonia injection nozzle 41 to be appropriately adjusted. The control device 9 controls the operation of the adjustment mechanism 7B so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature. This suppresses nitridation of the ammonia injection nozzle 41, as in the combustion device 100 described above.

In particular, the control device 9 controls the operation of the adjustment mechanism 7B so that the opening area of the injection port 41c of the ammonia injection nozzle 41 becomes smaller (i.e., so that the tip of the ammonia injection nozzle 41 becomes easier to cool) as the tip temperature of the ammonia injection nozzle 41 becomes higher. This appropriately achieves the temperature of the tip of the ammonia injection nozzle 41 being kept below the reference temperature.

In the above, an example was described in which the adjustment mechanism 7B for adjusting the opening area of the injection port 41c of the ammonia injection nozzle 41 has a drive device 71B and deforms the variable part 41d at the tip of the ammonia injection nozzle 41. However, the adjustment mechanism 7B is not limited to the above example as long as it has the function of adjusting the opening area of the injection port 41c of the ammonia injection nozzle 41. For example, when a member that can move or extend radially inward from the inner periphery of the tip of the main body 41a of the ammonia injection nozzle 41 is provided, a mechanism having the member and a drive device that drives the member may correspond to the adjustment mechanism 7B. Also, for example, when a valve body having a shape that tapers toward the tip side is provided inside the tip of the ammonia injection nozzle 41, a mechanism having the valve body and a drive device that moves the valve body in the axial direction may correspond to the adjustment mechanism 7B.

Figure 8 is a schematic diagram showing a combustion device 100C according to a third modified example. As shown in Figure 8, the combustion device 100C is an example in which the adjustment mechanism 7 in the above-mentioned combustion device 100 is replaced with an adjustment mechanism 7C.

The adjustment mechanism 7C has an air pipe 71C, an air supply source 72C, and a flow rate adjustment valve 73C. The air pipe 71C is arranged coaxially with the ammonia injection nozzle 41 and surrounding the ammonia injection nozzle 41. Air is supplied into the air pipe 71C (specifically, into the space between the air pipe 71C and the ammonia injection nozzle 41). The adjustment mechanism 7C adjusts the flow rate of air in the air pipe 71C (hereinafter also referred to as the air flow rate) to adjust the tip temperature of the ammonia injection nozzle 41.

The air pipe 71C includes a main body 71Ca, a supply port 71Cb, and an injection port 71Cc. The main body 71Ca has a cylindrical shape. The main body 71Ca is arranged coaxially with the main body 41a of the ammonia injection nozzle 41 so as to surround the main body 41a. However, the central axis of the main body 71Ca and the central axis of the main body 41a of the ammonia injection nozzle 41 do not have to exactly coincide, but may be within a predetermined range. The thickness, inner diameter, and outer diameter of the main body 71Ca are approximately constant regardless of the axial position. However, the thickness, inner diameter, and outer diameter of the main body 71Ca may change depending on the axial position.

The axial position of the tip of the main body 71Ca is approximately the same as the axial position of the tip of the main body 41a of the ammonia injection nozzle 41. However, the axial position of the tip of the main body 71Ca may be forward (i.e., furnace 2 side) or rearward of the tip of the main body 41a of the ammonia injection nozzle 41. The axial position of the rear end of the main body 71Ca is approximately the same as the axial position of the rear end of the main body 41a of the ammonia injection nozzle 41. However, the axial position of the rear end of the main body 71Ca may be forward (i.e., furnace 2 side) or rearward of the rear end of the main body 41a of the ammonia injection nozzle 41.

The supply port 71Cb is an annular opening formed between the rear end of the main body 71Ca and the rear end of the main body 41a of the ammonia injection nozzle 41. The supply port 71Cb is connected to the air supply source 72C. The injection port 71Cc is an annular opening formed between the tip of the main body 71Ca and the tip of the main body 41a of the ammonia injection nozzle 41. The injection port 71Cc faces the internal space of the furnace 2.

Air is supplied from air supply source 72C through supply port 71Cb into main body 71Ca. The air supplied into main body 71Ca flows through the space between the inner periphery of main body 71Ca and the outer periphery of main body 41a of ammonia injection nozzle 41. The air that passes through main body 71Ca is injected from injection port 71Cc toward the internal space of furnace 2. The air injected from injection port 71Cc is used for combustion in furnace 2.

The flow rate control valve 73C adjusts the flow rate of air supplied from the air supply source 72C to the air pipe 71C. The flow rate control valve 73C is provided in a flow path connecting the air supply source 72C and the supply port 71Cb of the air pipe 71C. The flow rate of ammonia supplied from the air supply source 72C to the air pipe 71C is adjusted by adjusting the opening of the flow rate control valve 73C. This adjusts the flow rate of air in the air pipe 71C (i.e., the air flow rate). Specifically, the greater the opening of the flow rate control valve 73C, the greater the air flow rate.

Here, the tip of the ammonia injection nozzle 41 is cooled by the air flowing through the air pipe 71C. The greater the air flow rate, the greater the cooling capacity (i.e., the capacity to cool the tip of the ammonia injection nozzle 41) of the air flowing through the air pipe 71C. Therefore, the adjustment mechanism 7C can adjust the tip temperature of the ammonia injection nozzle 41 by adjusting the air flow rate.

As with the combustion device 100 described above, the control device 9 controls the operation of the adjustment mechanism 7C so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature. Specifically, the higher the tip temperature of the ammonia injection nozzle 41, the greater the opening of the flow rate control valve 73C. As a result, the higher the tip temperature of the ammonia injection nozzle 41, the greater the air flow rate, and the higher the cooling capacity of the air flowing through the air pipe 71C. Therefore, the tip temperature of the ammonia injection nozzle 41 is appropriately kept equal to or lower than the reference temperature.

As described above, in the combustion device 100C according to the third modified example, the adjustment mechanism 7C adjusts the flow rate of air in the air pipe 71C (i.e., the air flow rate). This allows the tip temperature of the ammonia injection nozzle 41 to be appropriately adjusted. The control device 9 controls the operation of the adjustment mechanism 7C so that the tip temperature of the ammonia injection nozzle 41 is equal to or lower than the reference temperature. This suppresses nitridation of the ammonia injection nozzle 41, as in the combustion device 100 described above.

In particular, the control device 9 controls the operation of the adjustment mechanism 7C so that the higher the tip temperature of the ammonia injection nozzle 41, the larger the air flow rate (i.e., so that the tip of the ammonia injection nozzle 41 is more easily cooled). This allows the tip temperature of the ammonia injection nozzle 41 to be appropriately kept below the reference temperature.

Although the embodiments of the present disclosure have been described above with reference to the attached drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

In the above, an example was described in which a different adjustment mechanism (i.e., any one of adjustment mechanisms 7, 7A, 7B, and 7C) is provided in each of the combustion devices 100, 100A, 100B, and 100C. However, two or more adjustment mechanisms of adjustment mechanisms 7, 7A, 7B, and 7C may be used in combination in a combustion device.

In the above, an example has been described in which the air injection nozzle 42 is arranged radially outside the ammonia injection nozzle 41, the pulverized coal injection nozzle 43 is arranged radially outside the air injection nozzle 42, and a triple cylinder structure is formed by the ammonia injection nozzle 41, the air injection nozzle 42, and the pulverized coal injection nozzle 43. However, the configuration of the burner 4 is not limited to the above example. For example, the position of the pulverized coal injection nozzle 43 and the position of the ammonia injection nozzle 41 may be interchanged. Also, for example, the air injection nozzle 42 may be omitted from the configuration of the burner 4. In this case, for example, the burner 4 has a double cylindrical structure, and the space on the center side of the space partitioned by the double cylindrical structure becomes the ammonia flow path, and the space adjacent to the ammonia flow path on the radial outside may become the pulverized coal flow path.

In the above, an example has been described in which ammonia and pulverized coal are used as fuel in the furnace 2. However, the fuel used in the furnace 2 is not limited to the above example as long as it contains at least ammonia. For example, the fuel used together with ammonia in the furnace 2 may be a fuel other than pulverized coal (e.g., natural gas or biomass, etc.). Also, for example, the fuel used in the furnace 2 may be only ammonia.

In the above, an example has been described in which the combustion devices 100, 100A, 100B, and 100C are installed in the furnace 2 of a boiler. However, the furnace in which the combustion devices 100, 100A, 100B, and 100C are used may be any furnace that burns fuel to generate combustion heat. The combustion devices 100, 100A, 100B, and 100C may be used in various furnaces in facilities other than boilers.

This disclosure will help stabilize combustion in combustion equipment used in boilers and the like, and reduce the frequency of repairs to combustion equipment, thereby contributing, for example, to Sustainable Development Goal (SDG) Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13 "Take urgent action to combat climate change and its impacts."

1: Boiler 2: Furnace 4: Burner 7: Adjustment mechanism 7A: Adjustment mechanism 7B: Adjustment mechanism 7C: Adjustment mechanism 9: Control device 41: Ammonia injection nozzle 41c: Injection port 71C: Air pipe 100: Combustion device 100A: Combustion device 100B: Combustion device 100C: Combustion device

Claims (5)

a burner having an ammonia injection nozzle at a tip of which an injection port facing an internal space of the furnace is provided;
an adjustment mechanism for adjusting the temperature of the tip portion;
a control device that controls the operation of the adjustment mechanism so that the temperature of the tip portion is equal to or lower than a reference temperature;
Equipped with
The adjustment mechanism includes a mechanism for adjusting an opening area of the injection port.
Combustion device. a burner having an ammonia injection nozzle at a tip of which an injection port facing an internal space of the furnace is provided;
an air pipe arranged coaxially with the ammonia injection nozzle so as to surround the ammonia injection nozzle;
an adjustment mechanism for adjusting the temperature of the tip portion;
a control device that controls the operation of the adjustment mechanism so that the temperature of the tip portion is equal to or lower than a reference temperature;
Equipped with
The adjustment mechanism includes a mechanism for adjusting the flow rate of air in the air pipe.
Combustion device. The adjustment mechanism includes a mechanism for adjusting a flow rate of ammonia in the ammonia injection nozzle.
A combustion device according to claim 1 or 2 . The adjustment mechanism includes a mechanism for adjusting a separation distance between the injection port and the internal space.
Combustion device according to any one of claims 1 to 3 . A boiler comprising the combustion device according to any one of claims 1 to 4 .

Images