WO2018181366A1

WO2018181366A1 - Boiler system

Info

Publication number: WO2018181366A1
Application number: PCT/JP2018/012522
Authority: WO
Inventors: 竜徳柴田; 阿川　隆一
Original assignee: 住友重機械工業株式会社
Priority date: 2017-03-29
Filing date: 2018-03-27
Publication date: 2018-10-04
Also published as: MY196720A; PH12019502105A1; KR102454609B1; KR20190129825A; JP7065829B2; JPWO2018181366A1

Abstract

A boiler system equipped with a furnace for burning fuel, and an exhaust gas passage through which exhaust gas generated in the furnace passes, and in the interior of which a pipe-shaped member is arranged. The furnace is provided with a spraying unit for spraying a chemical compound containing Mg into the furnace.

Description

Boiler system

The present invention relates to a boiler system.

As a conventional boiler system, one having a furnace for burning fuel and an exhaust gas passage provided on the downstream side of the furnace and allowing exhaust gas generated in the furnace to pass through is known. A tubular member is disposed in the exhaust gas passage, and the tubular member superheats a fluid such as steam in the tubular member by the heat of the exhaust gas passing through the exhaust gas passage. In recent years, biomass, such as construction waste wood, such as waste tires, waste plastics, and RPF, is sometimes used as the fuel for the furnace. There arises a problem that dust generated by burning such biomass fuel and waste fuel adheres to the tubular member and the tubular member is corroded. With respect to such a problem, in Patent Document 1, corrosion of the tubular member is suppressed by adding an additive to the combustion gas in the combustion gas flow path downstream of the furnace. .

Japanese Patent No. 4028801

However, in the above boiler system, the effect of reducing the amount of deposits adhering to the surface of the tubular member due to the flow of exhaust gas from the furnace is not sufficient. Therefore, it has been desired to further reduce the amount of deposits attached to the tubular member.

From the above, it is an object to provide a boiler system that can suppress the adhesion of deposits to a tubular member disposed in an exhaust gas flow path on the downstream side of a furnace.

A boiler system according to an aspect of the present invention is a boiler system including a furnace that burns fuel, and an exhaust gas passage in which exhaust gas generated in the furnace passes and a tubular member is disposed inside the furnace system. A spraying part for spraying a compound containing Mg is provided in the furnace.

In the boiler system according to one embodiment of the present invention, the furnace is provided with a spraying section for spraying a compound containing Mg in the furnace. According to such a configuration, the supply of the compound is not performed in the exhaust gas passage where adhesion of the molten salt to the tubular member occurs but in the furnace upstream of the exhaust gas passage. Therefore, it is possible to convert the molten salt into a compound that hardly adheres to the tubular member before the molten salt adheres to the tubular member. Moreover, the compound supplied to a furnace contains Mg. Further, the low melting point molten salt adhering to the tubular member of the exhaust gas passage exists as a gas in the combustion gas in the high temperature furnace. On the other hand, when the compound containing Mg is sprayed on the furnace by the spraying section, the compound is supplied in a state substantially close to gas in the furnace. Thereby, the chemical reaction between the compound and the molten salt proceeds as well as a reaction between gases. By the above, adhesion of the deposit | attachment to the tubular member arrange | positioned at the exhaust gas flow path of the downstream of a furnace can be suppressed.

In one embodiment, the furnace is provided with a fuel supply unit that supplies fuel into the furnace, and a gas outlet that discharges combustion gas generated in the furnace, and the spray unit includes a fuel supply unit and a gas outlet. The compound may be sprayed in the area between. In the region upstream of the fuel supply section, since it is a stage before fuel combustion occurs, no molten salt that causes deposits on the tubular member has yet occurred. The temperature of the combustion gas is lowered downstream from the gas outlet. Therefore, the spraying part can favorably advance the chemical reaction between the compound and the molten salt by spraying the compound in the region between the fuel supply part and the gas outlet.

In one form, a spray part sprays a compound by supplying a compound in a furnace with the pressurized air (pressurized gas) blown toward the inside of a furnace, and spread | diffuses a compound by adjusting the blowing amount of pressurized air. The position may be controlled. Thus, by using compressed air, the compound can be sprayed into the furnace in a sufficiently diffused state. Moreover, the diffusion position of the compound can be easily controlled by adjusting the blown amount of the compressed air.

In one form, the furnace is provided with a secondary combustion air supply section for supplying secondary combustion air (secondary combustion gas) into the furnace, and the spray section uses the secondary combustion air as the pressure air. Good. At the place where the secondary combustion air is supplied in the furnace, various substances contained in the combustion gas are well mixed. Therefore, by spraying the compound together with the secondary combustion air, the chemical reaction between the molten salt in the combustion gas and the compound can be favorably advanced.

In one form, the furnace is provided with a secondary combustion air supply part for supplying secondary combustion air (secondary combustion gas) into the furnace, and the spray part is in comparison with the fuel supply part and the gas outlet. You may provide in the position near the said secondary combustion air supply part. At the place where the secondary combustion air is supplied in the furnace, various substances contained in the combustion gas are well mixed. Therefore, by providing the spray part near the secondary combustion air supply part, the compound and the molten salt can be reacted in a well-mixed state. Thereby, the chemical reaction between the molten salt in the combustion gas and the compound can be favorably advanced.

According to the present invention, it is possible to provide a boiler system that can suppress adhesion of deposits to a tubular member disposed in an exhaust gas flow path downstream of a furnace.

It is a schematic structure figure of a boiler system concerning an embodiment of the present invention. It is a schematic block diagram of the furnace shown in FIG. It is a schematic block diagram of the furnace which concerns on a modification. It is a graph which shows the average adhesion ash weight of the deposit | attachment of the probe after conducting a test using each additive. It is a graph which shows the result of having measured the average estimated adhesion ash height of the deposit | attachment of the probe after testing using each additive. It is a photograph which shows the external appearance of the probe after testing using each additive.

Embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are merely examples for explaining the present invention and are not intended to limit the present invention to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

The configuration of the boiler system 100 according to the present embodiment will be described with reference to FIG. The boiler system 100 is an external circulation type (circulating fluidized bed type) circulating fluidized bed boiler. The boiler system 100 includes a fluidized bed furnace 3 having a vertically long cylindrical shape. A fuel supply port 3a for supplying fuel is provided in the middle part of the furnace 3, and a gas outlet 3b for discharging combustion gas is provided in the upper part. The fuel supplied from the fuel charging device 5 to the furnace 3 is supplied into the furnace 3 through the fuel supply port 3a. The fuel may include biomass such as construction waste wood, such as waste tires, waste plastics, and RPF.

A cyclone 7 that functions as a solid-gas separator is connected to the gas outlet 3 b of the furnace 3. The discharge port 7a of the cyclone 7 is connected to a downstream gas processing system via a gas line. A return line 9 called a downcomer extends downward from the bottom outlet of the cyclone 7, and the lower end of the return line 9 is connected to the intermediate side surface of the furnace 3.

In the furnace 3, the solid material containing the fuel supplied from the fuel supply port 3a flows by the combustion / flowing air introduced from the lower air supply line 3c, and the fuel flows while the fuel flows, for example, about 800 to 900. Burn at ℃. A combustion gas generated in the furnace 3 is introduced into the cyclone 7 with accompanying solid particles. The cyclone 7 separates solid particles and gas by a centrifugal separation action, returns the solid particles separated via the return line 9 to the furnace 3, and removes the combustion gas from which the solid particles have been removed from the discharge port 7 a to the gas line. To the subsequent gas processing system.

In this furnace 3, a solid material called “in-furnace bed material” is generated and collected at the bottom, and the bed material is sintered and melted and solidified by the concentration of impurities (low melting point materials, etc.) in the in-furnace bed material, or It is necessary to suppress malfunctions caused by incombustible impurities. For this reason, in the furnace 3, the in-furnace bed material is discharged | emitted regularly or continuously outside from the discharge port 3d of the bottom part. The discharged bed material is supplied to the furnace 3 again after removing unsuitable materials such as metal and coarse particle diameter on a circulation line (not shown).

The gas treatment system is connected to the gas heat exchange device (exhaust gas passage) 13 connected to the discharge port 7a of the cyclone 7 through a gas line, and connected to the discharge port 13a of the gas heat exchange device 13 through the gas line. The dust collector 15 is provided. The gas heat exchanger 13 is provided with a boiler tube 13b that superheats steam so as to cross the exhaust gas flow path. When the high-temperature exhaust gas sent from the cyclone 7 comes into contact with the boiler tube 13b, the heat of the exhaust gas is recovered into the steam in the tube, and the superheated high-temperature steam is used for power generation through the boiler tube (tubular member) 13b. Sent to the turbine. The dust collector 15 removes fine particles such as fly ash that are still accompanying the combustible gas. As the dust collector 15, for example, a bag filter or an electric dust collector is adopted. The clean gas discharged from the discharge port 15 a of the dust collector 15 is discharged from the chimney 19 to the outside via the gas line and the ventilator 17.

Solid particles generated in the furnace 3 circulate in the circulation system 21 including the furnace 3, the cyclone 7, and the return line 9. In the following description, the fluid of solid particles is referred to as a heat transfer medium. In the circulation system 21, a heat exchange chamber 20 is formed between the return line 9 and the bottom of the furnace 3. A heat transfer medium is stored in the heat exchange chamber 20. A heat exchanger 22 can be provided in the heat exchange chamber 20.

Next, a schematic configuration of the furnace will be described with reference to FIG. The furnace 3 is provided with a spray unit 30 for spraying a compound containing Mg in the furnace 3. As the compound containing Mg, for example, MgO · SiO ₂ , CaO · MgO · 2SiO ₂ , or a mixture thereof is employed.

Here, the fuel contains salts such as Na, K and Cl, and heavy metals such as lead and zinc. Accordingly, the combustion gas generated in the furnace 3 includes a low melting point molten salt such as KCl (melting point: 776 ° C.) or NaCl (melting point: 800 ° C.). Therefore, a molten salt such as KCl affects the progress of both ash adhesion and corrosion on the boiler tube 13b. Therefore, the spray unit 30 sprays a compound containing Mg, and reacts with the compound and a molten salt such as KCl, thereby converting it into a gas such as HCl gas and a high melting point ash. Thereby, ash adhesion to the boiler tube 13b can be suppressed.

The particle size of the compound is not particularly limited, but may be, for example, 15 μm or less. When the particle diameter is 15 μm or less, the reactivity between the compound and KCl or the like in the combustion gas can be improved because the compound particles are small. On the other hand, when the particle size is larger than 15 μm, the handleability of the compound is improved. The amount of the compound added to the furnace 3 may be such that the molar ratio of Mg and Cl contained in the fuel and the compound is 2 to 3 (“molar ratio Mg / Cl = 2 to 3”).

Here, spraying is not simply supplying the compound by dropping it into the internal space of the furnace 3, but supplying the compound with sufficient diffusibility. Molten salt such as KCl in the combustion gas is in a gas state. Therefore, the compound can be supplied into the furnace 3 in a state where the compound can be regarded as a gas by being sprayed and supplied by the spray unit 30. Thereby, the reaction between the molten salt in the combustion gas and the compound can be brought into a state close to the reaction between the gases. Here, the advantage of approaching the reaction between gases will be described. For comparison, for example, the compound particles are poured into a molten salt in a liquid state (the particles are supplied in a dense state, not in a state where the particles are widely diffused like spray). Think about the reaction. In this case, it becomes a state close to the reaction between the liquid and the solid (or the reaction between the liquid and the liquid). The liquid is a state in which particles (atoms) constituting the substance are bonded together to form a dense aggregate. Therefore, in the reaction between the liquids, the aggregate in which the particles are bonded is brought into contact with another aggregate, and the reaction proceeds at the contacted portion. In the case of such a reaction mode, the particles existing inside away from the aggregate interface do not contact each other, so that the reaction does not proceed. Regarding the reaction between the liquid and the solid, since the solid is in a state in which particles are densely formed into a lump, explanation of the same meaning is valid. On the other hand, the gas is in a state where the particles (atoms) constituting the substance are moving in the space in a state of being separated from each other. Therefore, in the reaction between gases, compared with the reaction between liquids or the reaction between liquids and solids, the particles are more likely to contact (collision) in the entire space, so that the reaction is likely to proceed. Therefore, the reactivity of the molten salt and the compound can be improved by supplying the compound in a state that can be regarded as a gas by spraying the molten salt in a gas state.

As shown in FIG. 2, when the spray unit 30 is provided on the side wall of the furnace 3, a part of the sprayed compound reaches at least the central axis CL of the furnace 3. A part of the compound reaches the central axis CL at a position higher than the height position of the fuel supply port 3a. Further, since the sprayed compound is sufficiently diffused in the furnace 3, the density in the space of the furnace 3 is lower than when the compound is simply dropped and supplied. The spray unit 30 may not be provided on the side wall of the furnace 3, and the spray unit 30 may be provided on the ceiling of the furnace 3, and the spray unit 30 may spray the compound downward. In this case, the sprayed compound is supplied so as to spread sufficiently in the horizontal direction. For example, the sprayed compound spreads over a wider range than half the width of the furnace 3 in the horizontal direction (indicated by the dimension “R” in FIG. 2). The compound spreads over a range wider than half the width dimension (dimension R) at a position above the height position of the fuel supply port 3a.

The spray unit 30 sprays the compound in a region between the fuel supply port 3a and the gas outlet 3b which are fuel supply units. Note that the position where the compound is sprayed may be in the above-described region regardless of the position where the spray unit 30 is attached.

The spray unit 30 may spray the compound by supplying the compound into the furnace 3 together with the pressurized air (pressurized gas) blown into the furnace 3. That is, a pressure-feed air supply unit (pressure-feed gas supply unit) 31 for blowing pressure-feed air into the furnace 3 is provided, and the compound supply unit 32 supplies the compound to a flow path through which the pressure-feed air passes. Thereby, since the force of pumping air acts on the compound, it is sufficiently diffused in the furnace 3. Moreover, the spraying part 30 can control the diffusion position of the compound by adjusting the amount of blown-in air. For example, when the spray unit 30 wants to spread the compound diffusion position to a position farther from the side wall of the furnace 3, the spray unit 30 sends a control signal to the pumped air supply unit 31 to increase the amount of blowing of the pumped air supply unit 31. Or the spraying part 30 raises the blowing amount of pressurized air by raising the opening degree of the valve (not shown) of the line of pressurized air.

Further, the furnace 3 is provided with a secondary combustion air supply part (secondary combustion gas supply part) 34 for supplying secondary combustion air into the furnace 3. The spray unit 30 is provided at a position closer to the secondary combustion air supply unit 34 than the fuel supply port 3a and the gas outlet 3b which are fuel supply units. That is, when the spray unit 30 is provided between the secondary combustion air supply unit 34 and the gas outlet 3b, the spray unit 30 is provided near the secondary combustion air supply unit 34. When the spray unit 30 is provided between the secondary combustion air supply unit 34 and the fuel supply port 3a, the spray unit 30 is provided near the secondary combustion air supply unit 34. Thus, the spray unit 30 is provided in the vicinity of the secondary combustion air supply unit 34. The combustion gas is sufficiently diffused in the furnace 3 where the secondary combustion air is supplied. Therefore, by providing the spray unit 30 in the vicinity of the secondary combustion air supply unit 34, the compound can be sprayed toward the location where the combustion gas is diffused. Therefore, the molten salt such as KCl in the combustion gas and the compound The reactivity with can be improved. Note that “near the secondary combustion air supply unit 34” means “distance = R / 2 (R is a half of the horizontal width of the furnace 3) with the secondary combustion air supply unit 34 as a base point. ) ”.

Alternatively, the spray unit 30 may use secondary combustion air as the pressurized air. Specifically, as shown in FIG. 3, the compound supply unit 32 may supply the compound to the flow path of the secondary combustion air supply unit 34. As a result, the spraying unit 30 sprays the compound and simultaneously supplies secondary combustion air. Or the flow path of secondary combustion air may be branched, and the compound supply part 32 may supply a compound to the branched flow path.

Here, with reference to FIG. 4 to FIG. 6, a test for confirming the effect when a compound containing Mg is adopted as the compound added to the furnace 3 will be described.

In the test, a test apparatus simulating a gas heat exchanger (exhaust gas passage) 13 was used. The test apparatus has a location where the sample ash is reacted and a location where a probe for adhering deposits is arranged downstream of the location. The temperature of the reaction part for reacting the sample ash was set at 750 ° C., and the temperature at the position where the probe was placed was set at 480 ° C. As the sample ash, a bio-only firing pilot test fly ash to which a KCl reagent was added to which a predetermined additive was added (or not added) was prepared. Specifically, a test with sample ash without addition of additive (No 1) and a test sample ash with (NH ₄ ) ₂ SO ₄ added and having a “molar ratio: S / Cl = 1” ( No2), and test (No3) in which “molar ratio: S / Cl = 4” and test sample ash to which an Al-containing compound was added, wherein “molar ratio: Al / Cl = 0.6” (No4) and test ash (Molar ratio: Al / Cl = 2.4) and sample ash to which an Mg-containing compound was added, wherein the molar ratio: Mg / Cl = 1.2 And a test (No7) in which “molar ratio: Mg / Cl = 2.5” was performed. In each test, the sample ash was supplied by air to the reaction part of the test apparatus. After heating with the test apparatus was continued for 10 hours, the deposits adhering to the probe were observed.

The state of the probe obtained by the above test is shown in FIG. What added the additive shows the external appearance of a thing with much addition amount. As shown in FIGS. 6 (a) and 6 (b), it was confirmed that a lot of deposits were attached to the non-added one and the one added with (NH ₄ ) ₂ SO ₄ . On the other hand, as shown in FIGS. 6 (c) and 6 (d), it was confirmed that the addition of the Al-containing compound and the addition of the Mg-containing compound suppressed the adhesion of the deposit to the probe. . FIG. 4 shows the result of measuring the average attached ash weight of the probe deposit, and FIG. 5 shows the result of measuring the average estimated ash height of the probe deposit. 4 and 5, the value related to the result of the test (No1) using the sample ash without the additive is “1.0”, and No2 to No.7 indicate the ratios to No1. As shown in FIG.4 and FIG.5, compared with what added Al containing compound, what added Mg containing compound showed a small value in both average adhesion ash weight and average estimated adhesion ash height. As a result, the effect of suppressing deposits was confirmed. Moreover, in any additive, it was confirmed that the effect of suppressing deposits was increased by increasing the additive. In addition, after the measurement, when the adhering material after adhering to the probe is rubbed with a brush, compared with the one added with (NH ₄ ) ₂ SO ₄ , the one containing the Al-containing compound and the one containing the Mg-containing compound added Was able to easily peel off the deposits. From this, it is understood that, even if deposits adhere to the tubular member, the deposits can be easily removed when a compound containing Mg is added.

Next, operations and effects of the boiler system 100 according to the present embodiment will be described.

First, the boiler system which does not have the spray part 30 like this embodiment as a boiler system which concerns on a comparative example is demonstrated. The low melting point molten salt generated in the furnace 3 reaches the downstream gas heat exchange device (exhaust gas passage) 13 together with the combustion ash while being contained in the combustion gas and exhaust gas. A boiler tube (tubular member) 13b provided in the gas heat exchanger 13 functions as a superheater that generates high-temperature and high-pressure steam to be used for power generation. Since the surface temperature of the boiler tube 13b is lower than the surrounding exhaust gas temperature, a molten salt such as KCl existing as a gas in the exhaust gas is condensed as a liquid on the surface of the boiler tube 13b and is deposited together with the combustion ash. Further, this causes a problem that the boiler tube 13b is corroded.

In contrast, in the boiler system 100 according to the present embodiment, the furnace 3 is provided with a spray unit 30 for spraying a compound containing Mg in the furnace 3. According to such a configuration, the supply of the compound is not performed in the gas heat exchanger 13 in which the molten salt adheres to the boiler tube 13b, but is performed in the furnace 3 on the upstream side of the gas heat exchanger 13. Is called. Therefore, the molten salt can be converted into a compound (a high melting point compound) that hardly adheres to the boiler tube 13b at a stage before the molten salt adheres to the boiler tube 13b. Moreover, the compound supplied to the furnace 3 contains Mg. The melting point of the compound containing Mg is closer to the temperature in the furnace 3 than other additives (for example, a compound containing Al). Therefore, by spraying such a Mg-containing compound into the furnace 3, the chemical reaction between the molten salt in the reaction gas and the compound proceeds well in the furnace 3. Moreover, the low melting point molten salt adhering to the boiler tube 13 b of the gas heat exchanger 13 exists as a gas in the combustion gas in the furnace 3. On the other hand, when a compound containing Mg is sprayed on the furnace 3 by the spraying unit 30, the compound is supplied to the furnace 3 in a state substantially close to a gas. Thereby, the chemical reaction between the compound and the molten salt proceeds as well as a reaction between gases. By the above, adhesion of the deposit | attachment to the boiler tube 13b arrange | positioned at the gas heat exchange apparatus 13 of the downstream of the furnace 3 can be suppressed. Moreover, even if a deposit | attachment adheres to the boiler tube 13b, it can be made to peel easily.

In the boiler system 100, the furnace 3 is provided with a fuel supply port 3 a that supplies fuel into the furnace 3 and a gas outlet 3 b that discharges combustion gas generated in the furnace 3. The compound may be sprayed in a region between the supply port 3a and the gas outlet 3b. In the region upstream of the fuel supply port 3a, which is the fuel supply unit, is a pre-stage where fuel combustion occurs, and thus no molten salt causing deposits on the boiler tube 13b has yet occurred. On the downstream side of the gas outlet 3b, the temperature of the combustion gas is lowered. Therefore, the spraying part 30 can advance the chemical reaction between the compound and the molten salt satisfactorily by spraying the compound in the region between the fuel supply port 3a and the gas outlet 3b.

In the boiler system 100, the spraying unit 30 sprays the compound by supplying the compound into the furnace 3 together with the pressurized air that is blown into the furnace 3, and the diffusion of the compound by adjusting the blowing amount of the pumped air. The position may be controlled. As described above, by using the compressed air, the compound can be sprayed into the furnace 3 in a sufficiently diffused state. Moreover, the diffusion position of the compound can be easily controlled by adjusting the blown amount of the compressed air.

In the boiler system 100, the furnace 3 is provided with a secondary combustion air supply unit 36 that supplies secondary combustion air into the furnace 3, and the spray unit 30 may use the secondary combustion air as the pressurized air. . In the furnace 3 where the secondary combustion air is supplied, various substances contained in the combustion gas are well mixed. Therefore, by spraying the compound together with the secondary combustion air, the chemical reaction between the molten salt in the combustion gas and the compound can be favorably advanced.

In the boiler system 100, the furnace 3 is provided with a secondary combustion air supply unit 36 that supplies secondary combustion air into the furnace 3, and the spray unit 30 includes a fuel supply port 3 a that is a fuel supply unit and a gas outlet. It may be provided at a position closer to the secondary combustion air supply unit 34 than 3b. In the furnace 3 where the secondary combustion air is supplied, various substances contained in the combustion gas are well mixed. Therefore, by providing the spray unit 30 near the secondary combustion air supply unit 36, the compound and the molten salt can be reacted in a well-mixed state. Thereby, the chemical reaction between the molten salt in the combustion gas and the compound can be favorably advanced.

A method for preventing corrosion of a boiler system is a method for preventing corrosion of a boiler system comprising: a furnace for burning fuel; and an exhaust gas passage through which exhaust gas generated in the furnace passes and in which a tubular member is disposed. The method for preventing corrosion of a boiler system in which a compound containing Mg is sprayed.

The present invention is not limited to the embodiment described above.

The overall configuration of the boiler system according to the above-described embodiment is merely an example, and may be appropriately changed within the scope of the present invention. Further, the configuration of the furnace is not limited to the above-described embodiment, and the shape and the like may be changed as appropriate.

In the boiler system according to the above-described embodiment, the compound is sprayed using the pressurized air, but instead of this, a method of supplying the fuel and the compound to the furnace at the same time from the fuel input device in a state where the fuel and the compound are mixed in advance may be adopted. Good.

DESCRIPTION OF SYMBOLS 3 ... Furnace, 3a ... Fuel supply port (fuel supply part), 3b ... Gas outlet, 13 ... Gas heat exchange apparatus (exhaust gas passage), 13b ... Boiler tube (tubular member), 30 ... Spraying part, 34 ... Secondary combustion Air supply unit, 100 ... boiler system.

Claims

A furnace that burns fuel;
An exhaust gas passage through which exhaust gas generated in the furnace passes and a tubular member is arranged inside, a boiler system comprising:
The boiler system is provided with a spray section for spraying a compound containing Mg in the furnace.
The furnace is provided with a fuel supply unit for supplying the fuel into the furnace, and a gas outlet for discharging combustion gas generated in the furnace,
The boiler system according to claim 1, wherein the spraying unit sprays the compound in a region between the fuel supply unit and the gas outlet.
The spray section is
The compound is sprayed by supplying the compound into the furnace together with a pressurized gas blown into the furnace,
The boiler system according to claim 1 or 2, wherein a diffusion position of the compound is controlled by adjusting a blowing amount of the pressurized gas.
The furnace is provided with a secondary combustion gas supply unit for supplying secondary combustion gas into the furnace,
The boiler system according to claim 3, wherein the spraying unit uses the secondary combustion gas as the pressurized gas.
The furnace is provided with a secondary combustion gas supply unit for supplying secondary combustion gas into the furnace,
The boiler system according to claim 2, wherein the spray unit is provided at a position closer to the secondary combustion gas supply unit than the fuel supply unit and the gas outlet.