JP6950464B2 - boiler - Google Patents

Description

The present invention relates to a boiler.

Patent Document 1 below discloses a complex energy system that burns a fuel containing ammonia. This combined energy system adds ammonia to natural gas, which is the main fuel, and burns it for the purpose of reducing carbon dioxide emissions.

Japanese Unexamined Patent Publication No. 2016-032391

By the way, when ammonia is burned as a part of fuel, there is a concern that nitrogen oxides (NOx) contained in the combustion gas will increase. The background technology is solely aimed at reducing carbon dioxide emissions and does not offer any solution for reducing nitrogen oxides (NOx). When a carbon fuel such as natural gas and a nitrogen-containing fuel such as ammonia are burned together, it is indispensable to suppress an increase in nitrogen oxides (NOx) from the viewpoint of practicality.

For example, since ammonia has a property of reducing nitrogen oxides (NOx), it is conceivable to supply ammonia as a reducing agent to the combustion gas separately from the fuel and the supplied ammonia. Since the amount of nitrogen oxides (NOx) contained in the combustion gas is as small as several ppm, the amount of ammonia supplied for reducing the nitrogen oxides (NOx) is also small. If the flow rate of ammonia supplied as a reducing agent is increased more than necessary, ammonia remains in the exhaust gas, so it is necessary to limit the amount of ammonia actually supplied as a reducing agent to a small amount. However, when a small amount of ammonia is supplied, the ammonia supplied from the wall surface of the furnace or the like cannot reach the inside of the furnace or the like, and the nitrogen oxides (NOx) cannot be sufficiently reduced.

The present invention has been made in view of the above circumstances. In a boiler capable of burning ammonia as fuel, nitrogen supplied as a reducing agent is brought to the center of a furnace or the like to bring nitrogen to a small amount of reducing agent. The purpose is to more reliably reduce oxides (NOx).

The present invention employs the following configuration as a means for solving the above problems.

The first invention is a boiler including a combustion device capable of burning ammonia as fuel, a furnace equipped with the combustion device, and a flue for guiding a combustion gas generated by burning the fuel. An injection unit is installed in at least one of the furnace and the flue at a position downstream of the combustion device from the combustion device, and an injection unit that injects ammonia as a reducing agent toward the center of the furnace or the flue in a plan view. Adopt the configuration of preparing.

In the second invention, in the first invention, the injection portion is provided on the wall portion of the furnace or the flue, and the flow velocity of the supplied ammonia is increased to increase the flow velocity of the supplied ammonia in a plan view from the side. A configuration is adopted in which the injection nozzle ejects toward the central portion.

The third invention adopts the configuration in which the injection nozzle has only one injection opening for injecting ammonia in the second invention.

The fourth invention adopts the configuration in the second or third invention that includes a plurality of injection nozzles that inject the ammonia at different flow rates.

In the fifth aspect of the invention, in the first aspect of the present invention, the injection section is fixed to a superheater arranged in the upper part of the furnace and has a plurality of ports for ejecting ammonia downward. Adopt a configuration that is a tube.

The sixth invention adopts the configuration in which the injection portion is a nozzle header arranged inside at least one of the furnace or the flue and provided with a plurality of nozzles in the first invention. do.

A seventh aspect of the present invention is the first invention, wherein the injection portion is a multi-opening type injection nozzle having a tip portion located at the center portion in a plan view and having a plurality of injection openings at the tip portion. adopt.

The eighth invention adopts the configuration in which the seventh invention has the injection opening for injecting the ammonia in the horizontal direction and the injection opening for injecting the ammonia in the vertical direction.

According to the present invention, ammonia acting as a reducing agent is injected by the injection unit toward the center of the furnace or the flue in a plan view. Therefore, as compared with the case where a port is provided on the wall of the furnace or the flue to supply ammonia that acts as a reducing agent, the ammonia can be surely reached the central part of the furnace or the flue in a plan view. can. Therefore, according to the present invention, in a boiler capable of burning ammonia as fuel, ammonia supplied as a reducing agent can be easily reached at the center of a furnace or the like.

It is a schematic diagram which shows the main part structure of the boiler of 1st Embodiment of this invention. It is sectional drawing of the injection nozzle provided in the boiler of 1st Embodiment of this invention. It is a schematic diagram which shows the main part structure of the boiler of the 2nd Embodiment of this invention. It is a schematic diagram which shows the main part structure of the boiler of the 3rd Embodiment of this invention. It is a schematic diagram which shows the main part structure of the boiler of 4th Embodiment of this invention. It is a schematic diagram which shows the main part structure of the boiler of the 5th Embodiment of this invention. It is sectional drawing of the injection nozzle provided in the boiler of the 5th Embodiment of this invention. It is sectional drawing of the modification of the injection nozzle provided in the boiler of the 5th Embodiment of this invention. It is a schematic diagram which shows the main part structure of the boiler of the 6th Embodiment of this invention.

Hereinafter, an embodiment of the boiler according to the present invention will be described with reference to the drawings. In the drawings below, the scale of each member is appropriately changed in order to make each member recognizable.

(First Embodiment)
FIG. 1 is a schematic view showing a configuration of a main part of the boiler 1 of the first embodiment. As shown in FIG. 1, the boiler 1 includes a furnace 2, a flue 3, a burner 4 (combustion device), a two-stage combustion air supply unit 5, an ammonia supply unit 6, and a pulverized coal supply unit 7. I have.

The furnace 2 is composed of a furnace wall provided vertically and in a tubular shape, and is a furnace body that burns fuel such as ammonia or pulverized coal to generate combustion heat. In this furnace 2, high-temperature combustion gas is generated by burning fuel. Further, the bottom of the furnace 2 is provided with a discharge port 2a for discharging ash generated by combustion of fuel to the outside.

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

Although omitted in FIG. 1, the boiler 1 is provided with a superheater installed in the upper part of the furnace 2. The superheater generates steam by exchanging heat between the combustion heat generated in the furnace 2 and water. Further, although omitted in FIG. 1, the boiler 1 is provided with a reheater, an economizer, an air preheater and the like, if necessary.

The burner 4 is arranged on the lower wall of the furnace 2. A plurality of the burners 4 are installed in the circumferential direction of the furnace 2. Further, although omitted in FIG. 1, a plurality of burners 4 are also installed in the height direction of the furnace 2. These burners 4 are two-dimensionally and opposed to each other in the lower part of the furnace 2 to inject fuel and burn it. Each of these burners 4 is a composite burner that can be injected into the furnace 2 using ammonia and pulverized coal as fuel. Although omitted in FIG. 1, the furnace 2 is provided with an ignition device for igniting the fuel (ammonia and pulverized coal) injected from the burner 4. Further, although omitted in FIG. 1, the boiler 1 has a combustion air supply unit that supplies combustion air to the burner 4. The fuel (ammonia and pulverized coal) injected from each burner 4 into the furnace 2 together with the combustion air is ignited and burned by the action of the above-mentioned ignition device.

The burners 4 installed in the boiler 1 do not necessarily have to be the composite burners as described above. For example, a configuration including a coal-fired burner or an ammonia-fired burner can be adopted. However, in the boiler 1 of the present embodiment, at least one burner 4 is capable of burning using ammonia as fuel, and it is possible to co-fire ammonia and pulverized coal inside the furnace 2.

Here, ammonia is a compound _{of hydrogen (H) and nitrogen (N) as shown by the molecular formula (NH 3} ), and does not contain carbon (C) as a constituent atom. Although this ammonia (low carbon fuel) is known as a flame-retardant substance, it is a hydrogen carrier substance having three hydrogen atoms like _{methane (CH 3).} On the other hand, pulverized coal is a fossil fuel obtained by crushing coal to a size of about several micrometers, and is generally used as a fuel for boilers. That is, ammonia is a low-carbon fuel having a lower carbon concentration than pulverized coal (carbon fuel).

The two-stage combustion air supply unit 5 is connected to the furnace 2 above the burner 4, and supplies air for two-stage combustion to the inside of the furnace 2. By supplying air for two-stage combustion by such a two-stage combustion air supply unit 5, the unburned portion of the fuel burned by the burner 4 is burned by the two-stage combustion air, and the heat collection performance of the boiler 1 is improved. At the same time, the unburned content of the fuel contained in the exhaust gas can be reduced.

The ammonia supply unit 6 includes an ammonia supply source 6a, a fuel ammonia supply unit 6b, a reducing agent supply unit 6c, and an ammonia supply control device 6d. The ammonia supply source 6a includes a tank or the like for storing ammonia. The ammonia supply source 6a does not necessarily have to be a component of the ammonia supply unit 6. That is, the ammonia supply unit 6 may take in ammonia from the ammonia supply source 6a installed outside.

The fuel ammonia supply unit 6b includes a fuel ammonia supply pipe 6b1 that connects the ammonia supply source 6a and the burner 4, an overall flow rate control valve 6b2 and a fuel ammonia flow rate control valve 6b3 that are installed in the middle of the fuel ammonia supply pipe 6b1. It has. The fuel ammonia supply pipe 6b1 is a pipe that guides the portion (fuel ammonia) of the ammonia supplied from the ammonia supply source 6a that is supplied as fuel to the burner 4. The overall flow rate control valve 6b2 is a valve that regulates the overall flow rate of ammonia supplied from the ammonia supply source 6a to the fuel ammonia supply pipe 6b1. The total flow rate of ammonia is the flow rate of fuel ammonia plus the flow rate of ammonia (reducing agent ammonia) supplied to the furnace 2 or the like as a reducing agent via the reducing agent supply unit 6c. The fuel ammonia flow rate control valve 6b3 is arranged on the downstream side of the overall flow rate control valve 6b2, and is a valve that regulates the flow rate of fuel ammonia.

The reducing agent supply unit 6c supplies the reducing agent ammonia to a position downstream (that is, above) of the combustion gas from the burner 4, and is a reducing agent supply pipe 6c1 connected to the furnace 2 and a reducing agent supply pipe 6c1. It is provided with a reducing agent flow control valve 6c2 installed at an intermediate portion and an injection nozzle 6c3 (injection unit) connected to the reducing agent supply pipe 6c1. One end of the reducing agent supply pipe 6c1 is connected to the fuel ammonia supply pipe 6b1 between the overall flow rate control valve 6b2 and the fuel ammonia flow rate control valve 6b3. The reducing agent supply pipe 6c1 takes in a part of the fuel ammonia from the fuel ammonia supply unit 6b and guides it to the injection nozzle 6c3 as the reducing agent ammonia. The reducing agent flow rate control valve 6c2 is a valve that regulates the flow rate of the reducing agent ammonia.

FIG. 2A is a cross-sectional view of the injection nozzle 6c3 including the shaft core L, and FIG. 2B is a cross-sectional view taken along the line AA of FIG. 2A. As shown in these figures, the injection nozzle 6c3 is a cylindrical straight tube type nozzle centered on the shaft core L, and has only one injection opening 20 at the tip for injecting the reducing agent ammonia. .. The injection opening 20 is formed so that the center overlaps with the shaft core L of the injection nozzle 6c3. That is, as shown in FIG. 2B, the injection opening 20 is formed in the center of the injection nozzle 6c3 when viewed from the direction along the axis L of the injection nozzle 6c3. Further, the diameter D1 of the injection opening 20 is set smaller than the diameter D2 of the internal flow path of the injection nozzle 6c3. Such an injection nozzle 6c3 injects the reducing agent ammonia supplied from the reducing agent supply pipe 6c1 to the internal flow path to the outside through the injection opening 20. At this time, since the injection nozzle 6c3 has only one injection opening 20 having a diameter D1 smaller than the diameter D2 of the internal flow path, the reducing agent ammonia supplied to the internal flow path opens the injection opening 20. Accelerated as it passes. That is, the injection nozzle 6c3 injects the reducing agent ammonia supplied to the internal flow path at an increased flow rate.

As shown in FIG. 1, the injection nozzle 6c3 is provided on the wall portion of the furnace 2 so that the root portion connected to the reducing agent supply pipe 6c1 is fixed to the furnace 2, and the tip thereof is viewed in a plan view of the furnace 2. It is arranged horizontally toward the center. That is, the injection nozzle 6c3 is horizontally arranged so that the injection opening 20 faces the central portion of the furnace 2 in a plan view. Such an injection nozzle 6c3 injects the reducing agent ammonia supplied from the reducing agent supply pipe 6c1 from the side in the plan view of the furnace 2 toward the central portion in the plan view by increasing the flow velocity. As shown in FIG. 1, a plurality of injection nozzles 6c3 are provided. These injection nozzles 6c3 are arranged so as to surround the center of the furnace 2 at the same height position, for example.

For example, as shown in FIG. 1, inside the furnace 2 and the flue 3, a burner region R1 where a flame is formed, a staged combustion region R2 where staged combustion is performed, an upper part of the furnace 2 and a horizontal flue It is divided into an upper region R3 including the inside of 3a and a rear region R4 including the inside of the rear flue 3b. Here, in the present embodiment, the reducing agent supply unit 6c is provided with an injection nozzle 6c3 in the two-stage combustion region R2, and supplies the reducing agent ammonia to the two-stage combustion region R2. However, it is also possible to supply the reducing agent ammonia to the burner region R1, the upper region R3 or the rear region R4. It is also possible to supply the reducing agent ammonia to a plurality of the burner region R1, the staged combustion region R2, the upper region R3, and the rear region R4.

The ammonia supply control device 6d controls the overall flow rate control valve 6b2, the fuel ammonia flow rate control valve 6b3, and the reducing agent flow rate control valve 6c2. Adjust the opening. The ammonia supply control device 6d adjusts the total flow rate of ammonia taken in from the ammonia supply source 6a by adjusting the opening degree of the total flow rate control valve 6b2 based on an external command or the like.

Further, the opening degree between the fuel ammonia flow control valve 6b3 and the reducing agent flow control valve 6c2 determines the distribution of ammonia taken in from the ammonia supply source 6a to the fuel ammonia and the reducing agent ammonia. That is, the fuel ammonia flow rate control valve 6b3 and the reducing agent flow rate control valve 6c2 form a mechanism (distribution adjustment mechanism 6b4) for adjusting the distribution ratio of the fuel ammonia and the reducing agent ammonia. The ammonia supply control device 6d adjusts the distribution ratio of the fuel ammonia and the reducing agent ammonia by controlling the distribution adjusting mechanism 6b4 including the fuel ammonia flow rate control valve 6b3 and the reducing agent flow rate control valve 6c2.

Further, in the present embodiment, the ammonia supply control device 6d controls to adjust the total flow rate of ammonia, which is the sum of the flow rate of the reducing agent ammonia and the flow rate of the fuel ammonia, according to the flow rate of the reducing agent ammonia. For example, in the present embodiment, when the flow rate of the reducing agent ammonia is increased, the ammonia supply control device 6d increases the opening degree of the total flow rate control valve 6b2, and increases the total flow rate of ammonia by the increase in the flow rate of the reducing agent ammonia. Increases by the same amount as. Further, in the present embodiment, when the flow rate of the reducing agent ammonia is reduced, the ammonia supply control device 6d reduces the opening degree of the total flow rate control valve 6b2, and reduces the total flow rate of ammonia by the decrease in the flow rate of the reducing agent ammonia. It decreases by the same amount as. As a result, the flow rate of the fuel ammonia supplied to the burner 4 can be kept constant at all times.

The pulverized coal supply unit 7 is connected to the burner 4, and crushes the coal into pulverized coal and supplies the pulverized coal to the burner 4. The pulverized coal supply unit 7 includes, for example, a mill for pulverizing coal to a particle size of about several micrometers to obtain pulverized coal, and a coal feeder for supplying the pulverized coal produced by the mill to the burner 4. .. The pulverized coal supply unit 7 may be configured to directly supply the pulverized coal to the burner 4 from the mill without providing a coal feeder.

In such a boiler 1 of the present embodiment, fuel ammonia is supplied from the ammonia supply unit 6 to the burner 4, pulverized coal is supplied from the pulverized coal supply unit 7 to the burner 4, and the burner 4 uses the fuel ammonia and the pulverized coal as fuel. A flame is formed at. Further, the unburned fuel contained in the combustion gas is burned by supplying the air for the two-stage combustion to the inside of the furnace 2 by the two-stage combustion air supply unit 5. The combustion gas generated by burning the fuel moves from the lower part to the upper part of the furnace 2 and is guided to the outside through the flue 3.

Further, in the boiler 1 of the present embodiment, a part of the fuel ammonia is supplied to the inside of the furnace 2 as the reducing agent ammonia by the reducing agent supply unit 6c of the ammonia supply unit 6. As a result, nitrogen oxides (NOx) contained in the combustion gas are reduced. At this time, the reducing agent ammonia is injected toward the central portion in the plan view of the furnace 2 by increasing the flow velocity by the injection nozzle 6c3. Since the flow velocity of the reducing agent ammonia injected in this way is high, the penetrating force increases and reaches the central portion of the furnace 2 in a plan view. Therefore, nitrogen oxides (NOx) contained in the combustion gas can be reduced even in the central portion of the furnace 2 in a plan view.

According to the boiler 1 of the present embodiment as described above, the reducing agent ammonia is injected by the injection nozzle 6c3 toward the central portion of the furnace 2 in a plan view. Therefore, as compared with the case where a port is provided in the wall portion of the furnace 2 or the flue 3 to supply the reducing agent ammonia, the reducing agent ammonia can be surely reached the central portion in the plan view of the furnace 2. Therefore, according to the boiler 1 of the present embodiment, in a boiler combustible using ammonia as fuel, ammonia supplied as a reducing agent can be easily reached at the center of a furnace or the like. Therefore, according to the boiler 1 of the present embodiment, the ammonia supplied as the reducing agent can be easily reached at the center of the furnace 2, and the combustion gas is minimized while the ammonia supplied as the reducing agent is minimized. Nitrogen oxides (NOx) contained in the above can be reduced more reliably.

Further, in the boiler 1 of the present embodiment, the injection nozzle 6c3 is provided on the wall portion of the furnace 2 and injects the supplied ammonia from the side in the plan view toward the center in the plan view by increasing the flow velocity of the supplied ammonia. The reducing agent ammonia is brought to the center of the furnace 2 in a plan view. Therefore, with a simple structure, ammonia supplied as a reducing agent can be easily reached at the center of the furnace 2.

Further, in the boiler 1 of the present embodiment, the injection nozzle 6c3 is provided with only one injection opening 20 for injecting the reducing agent ammonia. Therefore, it is possible to accelerate the reducing agent ammonia supplied to the internal flow path of the injection nozzle 6c3 with a simple structure.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the description of the second embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified.

FIG. 3 is a schematic view showing a configuration of a main part of the boiler 1A of the second embodiment. As shown in this figure, in the boiler 1A of the second embodiment, a plurality of injection nozzles 6c3 are arranged in the height direction and provided. The injection nozzles 6c3 arranged at different positions in the height direction have injection openings 20 having different diameters (see FIG. 2), and inject the reducing agent ammonia at different flow rates. That is, in the present embodiment, a plurality of injection nozzles 6c3 for injecting the reducing agent ammonia at different flow rates are provided.

Further, in the boiler 1A of the present embodiment, the tip end portion of the reducing agent supply pipe 6c1 is branched and connected to each injection nozzle 6c3. Further, an on-off valve 6c8 opened and closed by the ammonia supply control device 6d is provided for each of the tip portions of the branched reducing agent supply pipe 6c1.

According to the boiler 1A of the present embodiment as described above, the flow velocity of the reducing agent ammonia is changed by selecting the injection nozzle 6c3 for injecting the reducing agent ammonia by adjusting the opening and closing of each on-off valve 6c8. Is possible.

For example, the nitrogen oxide (NOx) contained in the combustion gas determines the required flow rate of the reducing agent ammonia. When the flow rate of the reducing agent ammonia is small, the reducing agent ammonia is injected into the inside of the furnace 2 from the injection nozzle 6c3 that injects the reducing agent ammonia at a relatively high flow rate. On the contrary, when the required flow rate of the reducing agent ammonia is large, the reducing agent ammonia is injected into the inside of the furnace 2 from the injection nozzle 6c3 which injects the reducing agent ammonia at a relatively slow flow rate.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. In the description of the third embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified.

FIG. 4 is a schematic view showing a configuration of a main part of the boiler 1B of the third embodiment. As shown in this figure, in the boiler 1B of the third embodiment, a lower injection pipe 6c4 (injection portion) is provided for the superheater 8 arranged in the upper part of the furnace 2.

The lower injection pipe 6c4 is a member included in the reducing agent supply unit 6c and is connected to the reducing agent supply pipe 6c1. The lower injection pipe 6c4 has a plurality of ports for ejecting the reducing agent ammonia downward, and is provided so as to straddle the central portion of the furnace 2 in a plan view.

According to the boiler 1B of the present embodiment as described above, the reducing agent ammonia can be sent directly to the central portion of the furnace 2 by the lower injection pipe 6c4, and the nitrogen oxides (NOx) contained in the combustion gas can be more reliably produced. It becomes possible to reduce to. Further, since the lower injection pipe 6c4 is fixed to the superheater 8, it is not necessary to separately provide a member for supporting the lower injection pipe 6c4 or to improve the rigidity of the lower injection pipe 6c4.

(Fourth Embodiment)
Next, a fourth embodiment of the present invention will be described. In the description of the fourth embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified.

FIG. 5 is a schematic view showing a configuration of a main part of the boiler 1C of the fourth embodiment. As shown in this figure, in the boiler 1C of the fourth embodiment, the reducing agent supply unit 6c is arranged inside the furnace 2 and the nozzle header 6c5 (injection) that injects the reducing agent ammonia into the inside of the furnace 2. Department) is equipped. Such a nozzle header 6c5 is a straight pipe whose end is connected to the reducing agent supply pipe 6c1 and in which a plurality of nozzles are formed in the longitudinal direction. Such a nozzle header 6c5 disperses and injects the reducing agent ammonia supplied from the reducing agent supply pipe 6c1 from a plurality of nozzles.

According to the boiler 1C of the present embodiment as described above, even with a small amount of reducing agent ammonia, the reducing agent ammonia can be reliably reached to the central portion of the furnace 2, and nitrogen oxides (NOx) can be more reliably reached. Can be reduced. Further, according to the boiler 1C of the present embodiment, by changing the installation location of the nozzle header 6c5, it is possible to supply the reducing agent ammonia to an arbitrary region such as the furnace 2.

(Fifth Embodiment)
Next, a fifth embodiment of the present invention will be described. In the description of the fifth embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified.

FIG. 6 is a schematic view showing a configuration of a main part of the boiler 1D of the fifth embodiment. As shown in this figure, in the boiler 1D of the present embodiment, the reducing agent supply unit 6c includes a plurality of opening type injection nozzles 6c6 (injection unit) instead of the injection nozzle 6c3 of the first embodiment.

The multi-aperture injection nozzle 6c6 is longer than the injection nozzle 6c3 of the first embodiment, and has a length dimension such that the tip portion reaches the central portion in the plan view of the furnace 2. FIG. 7A is a cross-sectional view of the plurality of aperture injection nozzles 6c6 including the shaft core L, and FIG. 7B is a cross-sectional view taken along the line BB of FIG. 7A. As shown in these figures, a plurality of injection openings 21 for injecting the reducing agent ammonia in the horizontal direction are provided at the tip of the multiple opening type injection nozzle 6c6. As shown in FIG. 7B, these injection openings 21 are arranged in an annular shape so as to surround the axis L of the plurality of opening type injection nozzles 6c6.

Such a multi-opening type injection nozzle 6c6 disperses and ejects reducing agent ammonia from a plurality of injection openings 21 provided at the tip portion located at the central portion in a plan view of the furnace 2. According to the boiler 1D of the present embodiment provided with such a plurality of opening type injection nozzles 6c6, the reducing agent ammonia can be ejected over a wide range in the central portion of the furnace 2. Therefore, for example, it is possible to effectively bring the reducing agent ammonia to the central portion of the furnace 2 with a small number of pieces.

As shown in FIG. 8, instead of the multi-opening type injection nozzle 6c6, a multi-opening type injection nozzle 6c7 for injecting the reducing agent ammonia toward the radial outside (including the vertical direction) of the shaft core L is provided. It is also possible to adopt.

(Sixth Embodiment)
Next, a sixth embodiment of the present invention will be described. In the description of the sixth embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified.

FIG. 9 is a schematic view showing a configuration of a main part of the boiler 1E of the sixth embodiment. As shown in this figure, in the boiler 1E of the present embodiment, the fuel ammonia supply unit 6b and the reducing agent supply unit 6c are connected to different ammonia supply sources 6a. That is, in the boiler 1E of the present embodiment, the reducing agent supply unit 6c does not supply the reducing agent ammonia as a part of the reducing agent ammonia supplied as the fuel to the furnace 2, but the reducing agent ammonia dedicated to the reducing agent. Is supplied to the furnace 2.

According to the boiler 1E of the present embodiment as described above, when the flow rate of the reducing agent ammonia is changed, it is possible to prevent the change in the flow rate of the reducing agent ammonia from affecting the flow rate of the fuel ammonia. Therefore, a specified amount of fuel ammonia can always be supplied to the burner 4.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above embodiment. The various shapes and combinations of the constituent members shown in the above-described embodiment are examples, and can be variously changed based on design requirements and the like without departing from the spirit of the present invention.

For example, in the above embodiment, a boiler that co-fires pulverized coal and ammonia as fuel has been described. However, the present invention is not limited to this. For example, it is possible to adopt a configuration in which natural gas and ammonia are co-fired as fuel, a configuration in which heavy oil or light oil and ammonia are co-fired as fuel, a configuration in which only ammonia is burned as fuel, and the like.

Further, for example, a check valve may be provided in both or one of the fuel ammonia supply pipe 6b1 and the reducing agent supply pipe 6c1.

It is also possible to adopt a configuration in which an injection unit for injecting the reducing agent ammonia only upward is provided. It is also possible to adopt a configuration in which an injection unit for injecting the reducing agent ammonia only downward is provided. Further, both an injection unit that injects the reducing agent ammonia only upward and an injection unit that injects the reducing agent ammonia only downward may be provided to selectively supply the reducing agent ammonia. For example, when the reducing agent ammonia is injected upward, the reducing agent ammonia is injected along the flow direction of the combustion gas, so that the residence time of the reducing agent ammonia in the furnace 2 or the like can be shortened. Further, when the reducing agent ammonia is injected downward, the reducing agent ammonia is injected against the flow direction of the combustion gas, so that the residence time of the reducing agent ammonia in the furnace 2 or the like can be lengthened.

1 …… Boiler 1A …… Boiler 1B …… Boiler 1C …… Boiler 1D …… Boiler 1E …… Boiler 2 …… Fire furnace 2a …… Discharge port 3 …… Smoke path 3a …… Horizontal flue 3b …… Rear flue 4 …… Burner 5 …… Two-stage combustion air supply unit 6 …… Ammonia supply unit 6a …… Ammonia supply source 6b …… Fuel Ammonia supply unit 6b1 …… Fuel Ammonia supply pipe 6b2 …… Overall flow control valve 6b3 …… Fuel Ammonia flow control valve 6b4 …… Distribution control mechanism 6c …… Reducing agent supply unit 6c1 …… Reducing agent supply pipe 6c2 …… Reducing agent flow control valve 6c3 …… Injection nozzle (injection unit)
6c4 …… Lower injection pipe (injection part)
6c5 …… Nozzle header (injection part)
6c6 …… Multiple opening type injection nozzle (injection part)
6c7 …… Multiple opening type injection nozzle (injection part)
6c8 …… On-off valve 6d …… Ammonia supply control device 7 …… Pulverized coal supply unit 8 …… Superheater 20 …… Injection opening 21 …… Injection opening R1 …… Burner area R2 …… Two-stage combustion area R3 …… Upper Area R4 …… Rear area

Claims (2)

A boiler equipped with a combustion device capable of burning ammonia as fuel, a furnace equipped with the combustion device, and a flue for guiding the combustion gas generated by burning the fuel.
It is installed in the furnace at a position downstream of the combustion gas from the combustion device, and is provided with an injection unit that injects ammonia as a reducing agent toward the center of the furnace.
The injection unit is an injection nozzle provided on the wall portion of the furnace and injects the supplied ammonia from the side in a plan view toward the center portion of the furnace by increasing the flow velocity of the supplied ammonia.
The injection nozzle is provided with its tip extending horizontally from the wall portion of the furnace toward the central portion of the furnace, and has only one injection opening at the tip for injecting the ammonia.
A boiler characterized in that a plurality of the injection nozzles are arranged at the same height position so as to surround the central portion of the furnace. The boiler according to claim 1, further comprising a plurality of injection nozzles for injecting the ammonia at different flow rates.

Images