JP7261100B2 - ADDITIVE SUPPLY QUANTITY DETERMINATION DEVICE, COMBUSTION EQUIPMENT INCLUDING THE SAME, AND COMBUSTION EQUIPMENT OPERATION METHOD - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an additive supply amount determination device, combustion equipment having the same, and a method of operating the combustion equipment.

In combustion facilities for burning fuels containing metals (e.g. waste or biomass), the metals contained in the ash produced by combustion of the fuel usually react with chlorine compounds in the fuel to produce metal chlorides. Generate. When the temperature in the combustion gas drops, the metal chlorides contained in the combustion gas condense to form a highly corrosive molten salt, which can cause corrosion of equipment piping and the like.

As a countermeasure against the corrosion of equipment due to such corrosive molten salts, it has been proposed to add a sulfur-containing additive to the gaseous alkali metal chloride contained in the combustion gas. For example, in Patent Document 1, in a boiler provided with a superheater (heat transfer tube) on the downstream side of the combustion chamber, when burning solid chlorine-containing fuel, sulfur is added to the combustion gas at a position upstream of the superheater. Injection of contained additives is described. As a result, the highly corrosive alkali metal chloride contained in the combustion gas is converted into the relatively low corrosive alkali sulfate before reaching the superheater, thereby preventing corrosion of the superheater due to the alkali metal chloride. It is intended to suppress

Japanese Patent No. 4028801

By the way, fuels such as wastes and biomass that are burned in combustion equipment sometimes contain heavy metals. As with alkali metals, heavy metals also form chlorides in the combustion gas to become molten salts, which can cause the problem of corroding equipment. However, no effective countermeasure against corrosion by heavy metal salts contained in combustion gas has been found.

In view of the above circumstances, at least one embodiment of the present invention provides an additive supply amount determination device capable of suppressing corrosion of equipment caused by metals contained in fuel, combustion equipment having the same, and a method of operating the combustion equipment intended to provide

(1) An additive supply amount determination device according to at least one embodiment of the present invention,
An additive supply determination device for a combustion facility for burning a fuel containing heavy metals, comprising:
a detector configured to detect at least the content of heavy metals in ash produced by combustion of said fuel;
an addition amount determination unit configured to determine an addition amount of sulfur contained in an additive to be supplied to the fuel based on the detected heavy metal content.

As a result of extensive studies by the present inventors, highly corrosive heavy metal chlorides generated by fuel combustion react with sulfur oxides under environmental conditions in combustion equipment to form relatively low corrosive heavy metal sulfates. was found to change to In this regard, according to the above configuration (1), the amount of sulfur to be added to the fuel is determined based on the content of heavy metals in the ash generated by the combustion of the fuel. , the heavy metals contained in the fuel can be properly converted to relatively low corrosive sulfates. Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

(2) In some embodiments, in the configuration of (1) above,
The detection unit is configured to detect the content of alkali metals in the ash and the content of alkaline earth metals in the ash,
The addition amount determination unit determines the addition amount of sulfur contained in the additive to be supplied based on the detected heavy metal content, the alkali metal content, and the alkaline earth metal content. is configured to
The amount of sulfur added is calculated based on the number of moles of sulfur contained in the additive added per unit weight of the fuel, and the detected heavy metal, alkali metal, and alkaline earth metal. After weighting each of the number of moles of the heavy metal contained per unit weight of the fuel, the summed adjustment value is determined so as to approach each other,
The weighting process is performed based on the detected ionic valences of the heavy metals, the alkali metals, and the alkaline earth metals.

(3) In some embodiments, in the configuration of (1) or (2) above,
The detection unit is configured to detect at least the contents of calcium, sodium, potassium, zinc and lead in ash generated by combustion of the fuel,
The addition amount determination unit determines the number of moles m _Ca , m _Na , m _K , and m _Zn of calcium, sodium, potassium, zinc, and lead contained per unit weight of the fuel, based on the detection result of the detection unit. and m _Pb , and the number of moles m _S of sulfur contained in the additive added per unit weight of the fuel satisfies the following formula (A), so that the amount of the additive to be added is determined Configured.
0.95≦ _mS /( _mCa + _2mNa + _2mK + _mZn + _mPb ) (A)

Fuels such as waste and biomass typically contain alkali metals and alkaline earth metals such as calcium, sodium and potassium. According to the above configuration (3), the amount of additive added is determined so as to contain the amount of sulfur that satisfies the above formula (A), so the amount of additive determined in this way can be used. Therefore, most of the calcium, sodium, potassium, zinc (heavy metals) and lead (heavy metals) contained in the fuel, which can cause corrosion of the equipment, are removed in the combustion equipment by sulfates, which are relatively less corrosive. can be changed to Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

(4) In some embodiments, in the configuration of any one of (1) to (3) above,
The detection unit is configured to detect at least the contents of calcium, sodium, potassium, zinc and lead in ash generated by combustion of the fuel,
The addition amount determination unit determines the number of moles m _Ca , m _Na , m _K , and m _Zn of calcium, sodium, potassium, zinc, and lead contained per unit weight of the fuel, based on the detection result of the detection unit. and m _Pb , and the number of moles m _S of sulfur contained in the additive added per unit weight of the fuel satisfies the following formula (B), so that the amount of the additive to be added is determined Configured.
_mS /( _mCa + _2mNa + _2mK + _mZn + _mPb )≤1.05 (B)

Sulfur-containing materials can be converted to sulfur oxides in high temperature combustion equipment. In this respect, according to the configuration of (4) above, the amount of additive added is determined so as to contain the amount of sulfur that satisfies the above formula (B), so the amount of additive determined in this way is added. By using it, the amount of the additive containing sulfur is unlikely to be excessive. Therefore, it is possible to convert heavy metals and other substances contained in the fuel into sulfates in the combustion equipment while reducing the amount of sulfur oxide emissions from the combustion equipment. can be suppressed to

(5) In some embodiments, in the configuration of any one of (1) to (4) above,
The additive supply device for determining the amount of
A temperature adjustment unit for adjusting the combustion temperature of the fuel,
The detection unit is configured to detect at least zinc and lead contents in ash produced by combustion of the fuel,
The temperature adjustment unit is configured to adjust the combustion temperature to 950° C. or higher,
Based on at least the result of detection by the detection unit, the addition amount determination unit determines the number of moles m _Zn and m _Pb of zinc and lead contained per unit weight of the fuel, and sodium contained per unit weight of the fuel. and potassium, the number of moles _{mNa_vol} and _{mK_vol} of sodium and potassium volatilized during combustion of the fuel, and the number of moles _mS of sulfur contained in the additive added per unit weight of the fuel are as follows: It is configured to determine the additive amount of the additive so as to satisfy the formula (C).
0.95≦ _mS /( _{2mNa_vol} + _{2mK_vol} + _mZn + _mPb )≦1.05 (C)

Alkali metals and alkaline earth metals have higher reactivity with sulfur compounds than heavy metals such as zinc and lead. For this reason, when a large amount of alkali metals (sodium, potassium, etc.) or alkaline earth metals (calcium, etc.) are contained in fuel, in order to react heavy metals with sulfur compounds in the combustion equipment to form sulfates, A large amount of additive is required. In this respect, according to the above configuration (5), since the combustion temperature of the fuel is set to a high temperature of 950° C. or higher, at least a part of calcium, sodium, and potassium is deactivated by reacting with the mineral phase in the combustion part. be able to. As a result, the amount of highly corrosive metal chlorides derived from calcium, sodium, and potassium contained in fuel can be reduced, and the reaction between heavy metals contained in fuel and sulfur compounds can be promoted. Therefore, according to the configuration of (5) above, it is possible to effectively convert heavy metals contained in the fuel into sulfates in the combustion equipment while reducing the amount of additives containing sulfur. It is possible to appropriately suppress corrosion of equipment caused by metals that are exposed to metal.

Also, during combustion of the fuel, some of the sodium and potassium volatilize as highly corrosive chlorides without reacting with the mineral phase. In this regard, in the configuration of (5) above, the amount of additive added is determined so as to contain an amount of sulfur that satisfies 0.95 ≤ m _S / (2m _{Na_vol} + 2m _{K_vol} + m _Zn + m _Pb ). By using the amount of additive thus determined, most of the sodium, potassium, zinc, and lead that volatilize as chlorides during combustion of the fuel are replaced in the combustion facility with relatively less corrosive sulfates. can be appropriately changed to Also, in the configuration (5) above, the amount of additive added is determined so as to contain an amount of sulfur that satisfies (2m _{Na_vol} + 2m _{K_vol} + m _Zn + m _Pb ) ≤ 1.05. By using such an amount of the additive, the amount of the sulfur-containing additive is less likely to be excessive. Therefore, it is possible to convert heavy metals and other substances contained in the fuel into sulfates in the combustion equipment while reducing the amount of sulfur oxide emissions from the combustion equipment. can be suppressed to

(6) In some embodiments, in the configuration of (5) above,
The additive supply amount determination device,
Based on the temperature of the combustion gas generated by combustion of the fuel and the weight ratio of chlorine and sulfur contained in the combustion gas, the number of moles of volatilized sodium _{mNa_vol} and the number of moles of volatilized potassium _{mK_vol} are determined. It further comprises an estimator configured to estimate.

According to the above configuration (6), the number of moles _{mNa_vol} of volatilized sodium and the number of moles _{mK_vol} of volatilized potassium are estimated based on the temperature of the combustion gas and the weight ratio of chlorine and sulfur contained in the combustion gas. Therefore, the addition amount of the additive can be appropriately determined using the above formula (C).

(7) In some embodiments, in the configuration of any one of (1) to (6) above,
The additive supply amount determination device,
Adjusting the molar ratio of sulfur contained in the additive added to the fuel and ammonia that may be generated from the additive based on the concentration of nitric oxide in the combustion gas produced by combustion of the fuel. A configurable additive preparation section is further provided.

Ammonium salts (ammonium sulfate, ammonium hydrogen sulfate, etc.) may be used as additives containing sulfur. In this case, the ammonium salt generates ammonia by thermal decomposition, but depending on the amount of generated ammonia, so-called ammonia slip may occur in which part of the ammonia is discharged without being consumed in the combustion equipment. In this regard, according to the configuration of (7) above, the molar ratio between the sulfur contained in the additive and the ammonia that can be generated from the additive is based on the concentration of nitrogen monoxide that can react with ammonia in the combustion facility. can be adjusted, by appropriately setting this molar ratio, ammonia can be sufficiently consumed by the reaction with nitrogen monoxide in the combustion gas. Therefore, as described in (1) above, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel while suppressing the occurrence of ammonia slip caused by the addition of the additive.

(8) In some embodiments, in the configuration of (7) above,
The additive preparation unit selects one or more sulfur-containing substances to be used as the additive from a plurality of sulfur-containing substances having different amounts of ammonia generated per molecule, and extracts the one or more sulfur-containing substances. configured to determine the content in each said additive.

According to the above configuration (8), one or more sulfur-containing substances to be used as additives are selected from a plurality of types of sulfur-containing substances that generate different amounts of ammonia per molecule, and the one or more sulfur-containing substances are selected. Since the content of each of the substances in the additive is determined, it is possible to flexibly adjust the molar ratio between the sulfur contained in the additive and the ammonia that can be generated from the additive. Therefore, it is possible to effectively suppress the occurrence of ammonia slip caused by the addition of the additive, while appropriately suppressing the corrosion of equipment caused by the metal contained in the fuel.

(9) In some embodiments, in the configuration of (7) or (8) above,
The additive preparation unit sets the number of moles of sulfur contained in the additive added per unit weight of the fuel to _mS , and the unit of the fuel converted from the concentration of nitrogen monoxide in the combustion gas When n _NO is the number of moles of nitric oxide generated per weight,
ammonium sulfate is used as said additive when _nNO is greater than twice _mS ,
ammonium hydrogen sulfate is used as the additive when _nNO is greater than 1 and no more than 2 times _mS ,
It is configured to decide to use a sulfur-containing substance that does not contain ammonium ions as the additive when _nNO is less than or equal to 1 times _mS .

According to the configuration of (9) above, the number of moles m _S of sulfur indicating the amount of sulfur added by the additive, the number of moles n _NO of nitrogen monoxide indicating the concentration of nitrogen monoxide contained in the combustion gas, and Based on the ratio, one or more sulfur-containing substances used as additives are selected from a plurality of sulfur-containing substances with different amounts of ammonia generated per molecule. It is possible to effectively suppress the occurrence of ammonia slip. Therefore, while effectively suppressing the occurrence of ammonia slip, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

(10) Combustion equipment according to at least one embodiment of the present invention,
Combustion equipment for burning fuel containing heavy metals,
a flue through which combustion gas generated by combustion of the fuel flows;
a heat transfer tube provided in the flue;
a capturing part provided downstream of the heat transfer tube in the flue for capturing the ash entrained in the combustion gas;
an additive supply configured to add a sulfur-containing additive to the fuel before or during combustion;
The additive supply amount determination device according to any one of the above (1) to (9),
The detection unit is configured to detect the content of heavy metals in the ash captured by the capture unit.

According to the above configuration (10), the addition amount of the additive containing sulfur is determined based on the content of heavy metals in the ash generated by the combustion of the fuel and captured by the capture unit. In the combustion facility, heavy metals contained in the fuel can be properly converted to relatively low corrosive sulfates. Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

(11) A method of operating a combustion facility according to at least one embodiment of the present invention includes:
A method of operating a combustion facility for burning a fuel containing heavy metals, comprising:
a detection step of detecting the content of heavy metals in at least the ash produced by combustion of said fuel;
and an addition amount determination step of determining an addition amount of sulfur contained in the additive to be supplied to the fuel based on the content of the heavy metal detected in the detection step.

According to the above method (11), the amount of sulfur to be added to the fuel is determined based on the content of heavy metals in the ash generated by the combustion of the fuel. The contained heavy metals can be appropriately converted to relatively less corrosive sulfates. Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

According to at least one embodiment of the present invention, there are provided an additive supply amount determination device capable of suppressing corrosion of equipment caused by metals contained in fuel, combustion equipment having the same, and a method of operating the combustion equipment.

1 is a schematic diagram of a combustion facility including an additive supply amount determination device according to one embodiment; FIG. 1 is a schematic diagram of a combustion facility including an additive supply amount determination device according to one embodiment; FIG. FIG. 2 is a schematic configuration diagram of a control unit that constitutes an additive supply amount determination device according to one embodiment; 1 is a phase diagram of zinc (heavy metal) under given conditions; FIG. 1 is a phase diagram of lead (heavy metal) under given conditions; FIG. 5 is a graph showing an example of the correlation between temperature and ash shrinkage.

Several embodiments of the present invention will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. do not have.

1 and 2 are schematic diagrams of combustion equipment each including an additive supply amount determination device according to one embodiment. FIG. 3 is a schematic configuration diagram of a control unit that configures the additive supply amount determination device according to one embodiment.

As shown in FIGS. 1 and 2, the combustion facility 1 includes a combustion furnace 12 for burning fuel inside, a flue 4 for guiding combustion gas from the combustion furnace 12, and a flue 4 provided with a heat transfer tube 14, a capture section 18 provided downstream of the heat transfer tube 14 in the flue 4, an additive supply amount determination device 50 for supplying the additive to the fuel burned in the combustion furnace 12, It has Combustion furnace 12 , flue 4 , and heat transfer tubes 14 constitute boiler 2 .

The combustion furnace 12 is supplied with fuel from a fuel supply unit 8 and air from an air supply unit 10, and is configured to burn fuel inside the combustion furnace 12. . The fuel supplied from the fuel supply unit 8 is fuel containing heavy metals such as zinc and lead. For example, waste such as municipal waste and building materials, or biomass is supplied as the fuel.

In the combustion furnace 12, combustion gas and ash are generated by burning the fuel. Part of the ash accumulates in the lower portion of the combustion furnace 12 and is discharged to the outside of the combustion furnace 12 through an ash discharge section (not shown). A part of the ash is entrained in the combustion gas and led to the flue 4 as fly ash.

The heat transfer tube 14 is configured to heat a fluid (such as water) flowing inside the heat transfer tube 14 by heat exchange with high-temperature combustion gas flowing through the flue. The water heated in the heat transfer tubes 14 may be used, for example, as steam to drive a power generation turbine.

As shown in FIGS. 1 and 2 , a temperature reducing section 16 for reducing the temperature of the combustion gas flowing through the flue 4 may be provided downstream of the heat transfer tubes 14 in the flue 4 . The temperature reducing section 16 may be configured to reduce the temperature of the combustion gas by, for example, spraying water. The temperature reduction unit 16 may reduce the temperature of the combustion gas after passing through the heat transfer tubes 14 to a temperature range in which synthesis of predetermined substances (for example, dioxins) does not progress.

The trapping section 18 is configured to trap ash (fly ash) entrained in the combustion gases from the flue 4 . That is, the trap 18 is adapted to separate the ash from the ash-entrained combustion gases. As the capturing unit 18, for example, a dust collector such as a bag filter or an electric dust collector can be used.

The combustion gas from which ash has been removed by the trapping section 18 is discharged to the outside of the combustion facility 1 via the exhaust passage 5 and the chimney 6 connected to the trapping section 18 . A fan 22 may be provided in the exhaust passage 5 to suck the combustion gas. Also, the ash separated from the combustion gas by the trapping section 18 is discharged from the trapping section 18 via the discharge pipe 20 and the discharge valve 21 .

Hereinafter, the additive supply amount determination device 50 according to some embodiments will be described in more detail.
As shown in FIGS. 1 to 3, the additive supply amount determination device 50 according to one embodiment includes an additive supply unit 28 for supplying an additive containing sulfur to the fuel before or during combustion, and an ash A detection unit 26 for measuring the components inside and a control unit 40 including an addition amount determination unit 42 are provided.

Note that the control unit 40 may include a CPU, a memory (RAM), an auxiliary storage unit, an interface, and the like. The control device 30 receives signals from the various measuring instruments described above via an interface. The CPU is configured to process the signals received in this manner. Also, the CPU is configured to process a program expanded in the memory.

The processing contents of the control unit 40 may be implemented as a program executed by the CPU and stored in the auxiliary storage unit. During program execution, these programs are expanded in memory. The CPU reads a program from memory and executes instructions contained in the program.

In the exemplary embodiment shown in FIGS. 1 and 2, the additive supply 28 includes an additive supply line 29 for supplying additive to the fuel and an additive supply line 29 connected to the additive supply line 29 and containing sulfur. A first tank 30A for storing the first additive, a first supply pump 32A for pressurizing and feeding the first additive from the first tank 30A, and a controller for adjusting the supply amount of the first additive. and a first supply valve 34A.

In the exemplary embodiment shown in FIG. 2, the additive supply section 28 is further connected to the additive supply line 29, a second tank 30B containing a second additive different from the first additive; It includes a second supply pump 32B for pressurizing and feeding the second additive from the second tank 30B, and a second supply valve 34B for adjusting the supply amount of the second additive.

In the exemplary embodiment shown in FIG. 1, additive supply 28 is configured to supply one type of sulfur-containing additive (first additive) to the fuel. Also, in the exemplary embodiment shown in FIG. 2, the additive supply 28 selectively or in combination with two types of sulfur-containing additives (first additive and second additive), It is configured to be able to supply fuel. Note that, in another embodiment, the additive supply unit 28 may be configured to be able to supply three or more types of sulfur-containing additives to the fuel.

In some embodiments, additive supply 28 is configured to supply additives to the fuel prior to combustion. For example, the additive supply section 28 may be configured to supply the additive to the fuel supply section 8 (hopper or the like) in which the fuel before being supplied to the combustion furnace 12 is stored. Alternatively, in some embodiments, the additive supply 28 may be configured to supply the additive from above the fuel inside the combustion furnace 12 .

As an additive containing sulfur, for example, a sulfuric acid-containing substance such as sulfuric acid and fuming sulfuric acid, or a sulfate such as iron sulfate, aluminum sulfate, ammonium sulfate, and ammonium hydrogensulfate can be used.

The detector 26 is configured to detect at least the content of heavy metals in the ash produced by combustion of the fuel. In the exemplary embodiment shown in FIGS. 1 and 2, the detector 26 is configured to detect the content of heavy metals in the ash captured by the trap 18 . The detection unit 26 may, for example, collect the ash to be analyzed via the discharge pipe 20 through which the ash is discharged from the capture unit 18 .

The addition amount determination unit 42 is configured to determine the amount of additive added by the additive supply unit 28 based on the detection result of the detection unit 26 .

Note that the control unit 40 may control the additive supply unit 28 so as to supply the additive amount determined by the addition amount determination unit 42. For example, the first supply valve 34A And/or the degree of opening of the second supply valve 34B may be adjusted.

When a fuel containing heavy metals is burned, the heavy metals contained in the ash produced by combustion of the fuel generally react with chlorine compounds in the fuel to produce heavy metal chlorides. When the temperature in the combustion gas drops and the heavy metal chlorides contained in the combustion gas condense, a highly corrosive molten salt is formed, which can cause corrosion of equipment piping (for example, heat transfer pipes 14).

As a result of extensive studies by the present inventors, highly corrosive heavy metal chlorides generated by fuel combustion react with sulfur oxides under environmental conditions in combustion equipment to form relatively low corrosive heavy metal sulfates. was found to change to

That is, the melting point of heavy metal chlorides is about 300° C. to 500° C. Therefore, in a temperature range of about 300° C. or higher, heavy metal chlorides exist as relatively highly corrosive melts. On the other hand, the melting point of heavy metal sulfates is relatively high, about 700° C. to 1000° C., and under temperature conditions of about 700° C. or less, heavy metal sulfates exist as solids with relatively low corrosiveness.
And, as shown for example in the phase diagrams of FIGS. 4 and 5, when the _SO2 partial pressure in the atmosphere in which heavy metal chlorides are present increases, the heavy metals that constituted the chlorides with relatively low melting to a sulfate with a high melting point. That is, the addition of sulfur to the fuel increases the _SO2 partial pressure in the combustion gas, thus promoting the conversion of heavy metal chlorides present in the combustion gas to heavy metal sulfates. In a temperature range of about 700° C. or lower, heavy metal sulfates are present as solids, so corrosion due to heavy metal sulfates is less likely to occur.

4 and 5 are examples of phase diagrams of heavy metals in the presence of HCl (gas), SO ₂ (gas), O ₂ (gas) and H ₂ O (gas), respectively. FIG. 5 is a phase diagram for zinc and FIG. 5 is a phase diagram for lead. The phase diagrams of FIGS. 4 and 5 are under the conditions of a temperature of 573 K, a total pressure of 1 atm, a partial pressure of O ₂ of 0.01 atm, and a partial pressure of H ₂ O of 0.1 atm. , in each phase diagram, the vertical axis indicates the partial pressure of HCl and the horizontal axis indicates the partial pressure of _SO2 .

Here, a more specific description will be given of the chemical reaction that occurs in the combustion facility when the additive containing sulfur is added to the fuel containing heavy metals. Here, as an example, a case where a fuel containing lead (Pb) as a heavy metal and ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) as an additive containing sulfur are used will be described.

Ammonium sulfate (additive) added to the fuel as an additive is thermally decomposed in the combustion furnace 12 as shown in the following formula (D) to generate SO ₃ gas.
(NH ₄ ) ₂ SO ₄ (solid)→2NH ₃ (gas)+SO ₃ (gas)+H ₂ O (gas) (D)

On the other hand, lead Pb (heavy metal) contained in the fuel charged into the combustion furnace 12 forms chloride PbCl ₂ together with chlorine Cl contained in the fuel and volatilizes. Then, this volatilized chloride reacts with the SO ₃ gas produced in the above formula (D) as shown in the following formula (E) to produce a sulfate.
PbCl ₂ (gas)+SO ₃ (gas)+H ₂ O (gas)→PbSO ₄ (solid)+2HCl (gas) (E)

Here, since heavy metal chlorides (PbCl ₂ and the like) have a relatively low melting point, they tend to become molten salt in combustion equipment and easily adhere to pipes and the like to cause corrosion. On the other hand, heavy metal sulfates (such as _PbSO4 ) have a higher melting point than heavy metal chlorides and exist as solids in combustion equipment. Therefore, the corrosiveness of heavy metal sulfates is significantly lower than that of heavy metal chlorides, and corrosion of piping and the like is less likely to occur.

In this regard, according to the additive supply amount determination device 50 according to the above-described embodiment, the addition amount of the additive containing sulfur is determined based on the content of heavy metals in the ash generated by combustion of the fuel. Therefore, in the combustion equipment 1, the heavy metals contained in the fuel can be appropriately changed into relatively low corrosive sulfates. Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

In addition, since the concentrations of heavy metals contained in fuels such as wastes and biomass are relatively uneven, it is difficult to determine the amount of sulfur to be added as an additive based on the heavy metal concentrations in the fuel. In this regard, in the above-described embodiment, the ash generated by fuel combustion and having a relatively uniform composition is analyzed, so the trend of the heavy metal content of the fuel can be properly grasped. Therefore, an appropriate amount of additive can be added according to the amount of heavy metals contained in the fuel.

Note that the detection unit 26 may be configured to collect and analyze the ash generated by the combustion of the fuel at regular intervals. Then, the heavy metal content obtained by the detection unit 26 may be fed back to the addition amount determination unit 42 at regular intervals. As a result, even if the amount of heavy metals contained in the fuel changes over time, an appropriate amount of additive can be added according to the change in the amount of heavy metals.

In some embodiments, detector 26 is configured to detect at least the content of calcium, sodium, potassium, zinc and lead in ash produced by combustion of the fuel. Further, the additive amount determination unit 42 determines the amount of additive added by the additive supply unit 28 based on the contents of calcium, sodium, potassium, zinc, and lead in the ash detected by the detection unit 26. is configured to

Among the metals contained in waste and biomass as fuel, typical metals that can form molten salts of highly corrosive chlorides include calcium, sodium, potassium, zinc (heavy metals), and lead (heavy metals). . For reference, the following table shows some examples of the composition of ash (fly ash) detected by the detector 26. In the table below, Plant A to Plant C are waste incineration facilities (combustion facilities), and the numerical values in the table are obtained from the analysis results of the ash (fly ash) collected at each plant. It is the content (weight ratio) of the component.

In the above-described embodiment, the amount of additive added is determined based on the content of these metals, including heavy metals. can be changed to Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

In some embodiments, the addition amount determination unit 42 determines the number of moles m _Ca , m _Na of each of calcium, sodium, potassium, zinc, and lead contained per unit weight of fuel based on the detection result by the detection unit 26 . , m _K , m _Zn and m _Pb , and the number of moles m _S of sulfur contained in the additive added per unit weight of fuel satisfies the following formula (A). configured to
0.95≦ _mS /( _mCa + _2mNa + _2mK + _mZn + _mPb ) (A)

The number of moles m _Ca , m _Na , m _K , m _Zn and m _Pb of calcium, sodium, potassium, zinc and lead contained per unit weight of fuel is the content of each component detected by the detection unit 26. Quantity, ie the content of calcium, sodium, potassium, zinc and lead in the ash produced by combustion of the fuel.

In the above-described embodiment, the amount of additive added is determined so as to contain the amount of sulfur that satisfies the above formula (A). Most of the calcium, sodium, potassium, zinc (heavy metal) and lead (heavy metal) contained in the combustion equipment and capable of causing corrosion of the equipment are appropriately converted into relatively low corrosive sulfates in the combustion equipment 1. be able to. Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

Note that when the additive is added to the fuel so that the number of moles of each metal described above satisfies m _S /(m _Ca +2m _Na +2m _K +m _Zn +m _Pb )=1, theoretically, calcium contained in the fuel , sodium, potassium, zinc and lead can be reacted with the sulfur contained in the additive. This is because each metal sulfate contains sulfuric acid (sulfur), calcium, zinc, and lead as divalent ions, while sodium and potassium are contained as monovalent ions.

In some embodiments, the addition amount determination unit 42 determines the number of moles m _Ca , m _Na of each of calcium, sodium, potassium, zinc, and lead contained per unit weight of fuel based on the detection result by the detection unit 26 . , m _K , m _Zn and m _Pb , and the number of moles m _S of sulfur contained in the additive added per unit weight of the fuel satisfies the following formula (B). configured to determine.
_mS /( _mCa + _2mNa + _2mK + _mZn + _mPb )≤1.05 (B)

The sulfur-containing substances change into sulfur oxides in the high-temperature combustion facility 1 (see formula (D) above). In this regard, according to the above-described embodiment, the amount of additive added is determined so as to contain the amount of sulfur that satisfies the above formula (B), so the amount of additive determined in this way is used. As a result, the amount of the additive containing sulfur is unlikely to be excessive. Therefore, while reducing the amount of sulfur oxides emitted from the combustion equipment 1, metals including heavy metals contained in the fuel can be changed to sulfates in the combustion equipment 1, and equipment caused by metals contained in the fuel corrosion can be appropriately suppressed.

In some embodiments, the additive supply determination device 50 includes a temperature adjustment section 44 for adjusting the combustion temperature of the fuel. The temperature adjustment unit 44 may adjust the above-described combustion temperature based on the detected value of the temperature sensor 36 configured to measure the temperature inside the combustion furnace 12 . The temperature adjustment unit 44 may adjust the above-described combustion temperature by adjusting the amount of fuel supplied and the amount of air supplied to the combustion furnace 12 .

In some embodiments, the temperature adjuster 44 may be configured to adjust the combustion temperature of fuel to 950° C. or higher.

Alkali metals and alkaline earth metals have higher reactivity with sulfur compounds than heavy metals such as zinc and lead. Therefore, when a large amount of alkali metals (sodium, potassium, etc.) or alkaline earth metals (calcium, etc.) are contained in the fuel, the alkali metals and alkaline earth metals combine with sulfuric acid derived from sulfur compounds in preference to heavy metals. . Therefore, a large amount of additive is required to react heavy metals with sulfur compounds in the combustion facility 1 to form sulfates.

Here, as shown in the graph of FIG. 6, at a high temperature of 950° C. or higher, at least part of the ash in the combustion gas melts. This is because at a high temperature of 950° C. or higher, calcium, sodium and potassium contained in the fuel react with mineral phases (SiO ₂ , Al ₂ O ₃ , or compounds containing these as main components) to form a melt. indicates that FIG. 6 is a graph showing an example of the correlation between the temperature (horizontal axis) and the shrinkage rate (melting rate) of ash (% by weight).

In the above-described embodiment, the combustion temperature of the fuel is set to a high temperature of 950° C. or higher, so in the combustion furnace 12, at least part of calcium, sodium, and potassium is converted to a mineral phase (SiO ₂ , Al ₂ O ₃ , or It can be deactivated by reacting with the compound that is the main component). As a result, the amount of highly corrosive metal chlorides derived from calcium, sodium, and potassium contained in fuel can be reduced, and the reaction between heavy metals contained in fuel and sulfur compounds can be promoted. Therefore, it is possible to effectively convert the heavy metals contained in the fuel into sulfates in the combustion equipment while reducing the amount of additives containing sulfur. can be suppressed to

In some embodiments, the temperature adjustment unit 44 is configured to adjust the combustion temperature of the fuel to 950° C. or higher, and the addition amount determination unit 42 adjusts the fuel the number of moles m _Zn and m _Pb of zinc and lead contained per unit weight of the fuel, the number of moles m _{Na_vol} and The addition amount of the additive is determined such that m _{K_vol} and the number of moles m _S of sulfur contained in the additive added per unit weight of fuel satisfy the following formula (C1).
0.95≦ _mS /( _{2mNa_vol} + _{2mK_vol} + _mZn + _mPb ) (C1)

The number of moles m _Zn and m _Pb of zinc and lead contained per unit weight of the fuel is the content of each component detected by the detection unit 26, that is, the zinc in the ash generated by the combustion of the fuel. and lead content. Further, the number of moles _{mNa_vol} and _{mK_vol} of sodium and potassium volatilized during combustion of the fuel among the sodium and potassium contained per unit weight of the fuel may be obtained by the estimating unit 46, which will be described later.

During fuel combustion, some of the sodium and potassium volatilize as highly corrosive chlorides without reacting with the mineral phase. In this regard, in the above-described embodiment, the amount of additive added is determined so as to contain the amount of sulfur that satisfies the above formula (C1). , most of sodium, potassium, zinc, and lead, which volatilize as chlorides when the fuel is burned, can be appropriately converted to relatively low corrosive sulfates in the combustion facility 1 . Therefore, it is possible to appropriately suppress corrosion of equipment caused by metals such as heavy metals contained in the fuel.

In the reaction for converting heavy metal chlorides to heavy metal sulfates, _SO3 is consumed as shown in formula (E) above, but part of _SO3 is converted to _SO2 in the reaction shown in formula (H) below. Since it is decomposed, it cannot participate in the reaction of formula (E) above.
_SO3 → _SO2 +1/ _2O2 (H)
In this respect, by determining the amount of the additive to be added so that the amount of sulfur that satisfies (C1) above is included, it is possible to add sulfur to the fuel to obtain a sufficient corrosion inhibiting effect.

In addition, in a certain plant, when sulfur was added as an additive in an amount satisfying m _S /(2m _{Na_vol} +2m _{K_vol} +m _Zn +m _Pb ) = 0.95, compared to the case where no sulfur-containing additive was added to the fuel, , the corrosion rate of the equipment could be reduced to about 5%. From this, it can be seen that the corrosion rate of equipment can be sufficiently reduced by determining the amount of additive to be added so that the amount of sulfur that satisfies the above formula (C1) is included.

In some embodiments, the temperature adjustment unit 44 is configured to adjust the combustion temperature of the fuel to 950° C. or higher, and the addition amount determination unit 42 adjusts the fuel the number of moles m _Zn and m _Pb of zinc and lead contained per unit weight of the fuel, the number of moles m _{Na_vol} and The addition amount of the additive is determined such that m _{K_vol} and the number of moles m _S of sulfur contained in the additive added per unit weight of fuel satisfy the following formula (C2).
_mS /( _{2mNa_vol} + _{2mK_vol} + _mZn + _mPb )≤1.05 (C2)

In the above-described embodiment, the amount of additive added is determined so as to contain the amount of sulfur that satisfies the above formula (C2). It is difficult for the amount of the additive to be used to become excessive. Therefore, while reducing the amount of sulfur oxide emissions from the combustion equipment 1, it is possible to convert heavy metals and the like contained in the fuel into sulfates in the combustion equipment, and the equipment caused by metals such as heavy metals contained in the fuel corrosion can be appropriately suppressed.

The additive supply amount determination device 50 further determines the number of moles _{mNa_vol} of sodium volatilized during fuel combustion among the sodium contained per unit weight of fuel, and the number of moles mNa_vol of potassium contained per unit weight of fuel during fuel combustion. An estimation unit 46 configured to estimate the number of moles _{mK_vol} of volatilized potassium may be provided. In this case, the addition amount of the additive can be determined based on the above formulas (C1) and/or (C2) using the estimation result by the estimation unit 46 .

In some embodiments, the estimating unit 46 calculates the number of moles of sodium that volatilizes based on the temperature of the combustion gas generated by combustion of the fuel and the weight ratio of chlorine and sulfur contained in the combustion gas. It may be configured to estimate m _{Na_vol} and the number of moles of potassium volatilized m _{K_vol} .

As a result of intensive studies by the present inventors, the temperature of the combustion gas, the number of moles m _{Na_vol} of sodium in the volatile matter in the combustion gas, the number of moles m _{K_vol} of potassium in the volatile matter, and the chlorine and sulfur contained in the combustion gas It was found that the weight ratio of . According to the above configuration, by measuring the temperature of the combustion gas and the weight ratio of chlorine and sulfur contained in the combustion gas, based on the above-mentioned correlation, the number of moles of sodium in the volatile matter in the combustion gas m _{Na_vol} and moles of volatile potassium m _{K_vol} can be estimated.
In addition, when the chlorine content and sulfur content in the fuel are known in advance, instead of the above-mentioned "weight ratio of chlorine and sulfur contained in the combustion gas", chlorine and sulfur contained in the fuel The weight ratio of sulfur may be used to estimate the moles of sodium volatiles m _{Na_vol} and the moles of potassium volatiles m _{K_vol} in the combustion gas.

The correlation described above can be expressed, for example, by the following formula (F).
[Concentration of volatilized Na]+[Concentration of volatilized K]={275×10 ⁶ ×[Cl/S in combustion gas]+353×10 ⁶ }×exp(−33×10 ³ /(T+273+11)) ( F)
T in the above formula (F) is the temperature of the combustion gas, and "Cl/S in the combustion gas" is the weight ratio of chlorine and sulfur contained in the combustion gas. It should be noted that the relational expression of the above formula (F) can be obtained by creating an approximation formula based on actual measurement values.

The temperature of the combustion gas may be detected by a temperature sensor 36 provided in the combustion furnace 12, for example. The weight ratio of chlorine and sulfur contained in the combustion gas may be calculated from the detection results of the chlorine concentration and sulfur concentration by the concentration sensor 38 provided in the exhaust passage 5, for example. The chlorine concentration and sulfur concentration in the combustion gas may be obtained by separate concentration sensors.

According to the above-described embodiment, based on the temperature of the combustion gas, the chlorine concentration in the combustion gas, and the weight ratio of chlorine and sulfur contained in the combustion gas, the number of moles of sodium to volatilize m _{Na_vol} The number of moles of potassium m _{K_vol} can be estimated. Also, based on the estimation result, the addition amount of the additive can be appropriately determined using the above formulas (C1) and/or (C2).

The additive supply amount determination device 50 may further include an additive preparation section 48 for adjusting the additive to be added to the fuel from two or more types of additives. For example, in the embodiment shown in FIG. 2, different types of additives are stored in multiple tanks 30A and 30B. In this embodiment, the additive preparation unit 48 adjusts the opening degrees of the first supply valve 34A and the second supply valve 34B to adjust the mixing ratio of the first additive and the second additive, It may be configured to adjust additives added to the fuel.

In some embodiments, the additive preparation unit 48 determines the amount of sulfur contained in the additive added to the fuel ( S) and ammonia (NH3) that can be generated from the additive may be configured to be adjustable.

As an additive containing sulfur, an ammonium salt (ammonium sulfate (( _NH4 ) _2SO4 ), ammonium hydrogensulfate (( _NH4 ) _HSO4 ), etc. ₎ may be used. In this case, the ammonia salt generates ammonia by thermal decomposition inside the combustion facility 1 . Within the combustion facility 1, ammonia is consumed by reacting with nitrogen monoxide gas contained in the combustion gas as in the following formula (G).
4NH ₃ +4NO+O ₂ →3N ₂ +6H ₂ O (G)

Here, when the amount of ammonia generated from the ammonia salt (additive) is within a predetermined range, the entire amount of ammonia thus generated is consumed by the reaction with nitrogen monoxide gas contained in the combustion gas. , ammonia is not discharged outside the combustion facility 1 . On the other hand, when the amount of ammonia generated is greater than the amount of nitrogen monoxide gas in the combustion gas, part of the ammonia is consumed by the reaction with nitrogen monoxide in the reaction according to the above formula (G), but the remaining ammonia can be discharged without being consumed in the combustion facility 1, and so-called ammonia slip may occur.

In this regard, according to the above-described embodiment, the molar ratio of sulfur contained in the additive and ammonia that can be generated from the additive is adjusted based on the concentration of nitrogen monoxide that can react with ammonia in the combustion facility 1. Since it is made adjustable, ammonia can be sufficiently consumed by the reaction with nitrogen monoxide in the combustion gas by appropriately setting this molar ratio. Therefore, it is possible to appropriately suppress the corrosion of equipment caused by the metal contained in the fuel while suppressing the occurrence of ammonia slip caused by the addition of the additive.

In some embodiments, the additive preparation unit 48 uses a plurality of sulfur-containing substances with different amounts of ammonia generated per molecule (specifically, the amount of ammonia generated by thermal decomposition) as additives. It is configured to select one or more sulfur-containing substances and determine the content of each of the one or more sulfur-containing substances in the additive.

Here, as the sulfur-containing substance constituting the additive, ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) generates two molecules of ammonia per molecule, and ammonium hydrogen sulfate ((NH ₄ )HSO ₄ ) generates 2 molecules of ammonia per molecule. Generates one molecule of ammonia. Further, sulfuric acid, fuming sulfuric acid, iron sulfate, or aluminum sulfate can generate zero ammonia molecules per molecule.

According to the above-described embodiment, one or more sulfur-containing substances to be used as additives are selected from a plurality of sulfur-containing substances with different ammonia generation amounts per molecule, and the one or more sulfur-containing substances Since the content in each additive is determined, it is possible to flexibly adjust the molar ratio between the sulfur contained in the additive and the ammonia that can be generated from the additive. Therefore, it is possible to effectively suppress the occurrence of ammonia slip caused by the addition of the additive, while appropriately suppressing the corrosion of equipment caused by the metal contained in the fuel.

When using two different sulfur-containing substances, one of them is stored in the first tank 30A as the first additive, the other is stored in the second tank 30B as the second additive, and each sulfur-containing substance can be supplied via the additive supply line 29 (see FIG. 2).

In some embodiments, the additive preparation section 48 sets the number of moles of sulfur (S) contained in the additive added per unit weight of fuel to m _{2 S} , and nitrogen monoxide (NO) in the combustion gas. When the number of moles of nitrogen monoxide generated per unit weight of fuel converted from the concentration of is n _NO , when n _NO is more than twice m _S , ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) may be configured to be used as an additive. Alternatively, ammonium bisulfate (( _NH4 ) _HSO4 ) may be configured to be used as an additive when _nNO is greater than 1 and less than or equal to 2 times _mS . Alternatively, when _nNO is less than or equal to 1 times _mS , a sulfur-containing substance that does not contain ammonium ions (e.g., sulfuric acid, oleum, iron sulfate, or aluminum sulfate, etc.) is configured to be used as an additive. may be

In the above-described embodiment, based on the ratio between the number of moles m _S of sulfur, which indicates the amount of sulfur added by the additive, and the number of moles of nitrogen monoxide, _nNO , which indicates the concentration of nitrogen monoxide contained in the combustion gas Then, one or more kinds of sulfur-containing substances to be used as additives are selected from a plurality of kinds of sulfur-containing substances that generate different amounts of ammonia per molecule.

For example, when the number of moles of nitric oxide, _nNO , is more than twice the number of moles of sulfur, _mS , the molar equivalent of ammonia can be consumed in the reaction with nitrogen monoxide, and thus ammonium sulfate is used. Can be used as an additive. Further, when the above-mentioned number of moles of nitrogen monoxide, n _NO , is more than 1 time and less than or equal to 2 times the number of moles of sulfur, _mS , 1 times the molar equivalent of ammonia can be consumed in the reaction with nitrogen monoxide. Therefore, ammonium bisulfate can be used as an additive. In addition, when the number of moles of nitrogen monoxide _nNO is less than or equal to the number of moles _mS of sulfur, sulfuric acid, fuming sulfuric acid, iron sulfate, or aluminum sulfate that does not generate ammonia by thermal decomposition is used as an additive. can be used.

In this way, depending on the amount of sulfur added by the additive and the concentration of nitrogen monoxide contained in the combustion gas, from multiple types of sulfur-containing substances with different ammonia generation amounts per molecule, use as an additive Since one or more kinds of sulfur-containing substances are selected, it is possible to effectively suppress the occurrence of ammonia slip caused by the addition of the additive. Therefore, while effectively suppressing the occurrence of ammonia slip, it is possible to appropriately suppress corrosion of equipment caused by metals contained in the fuel.

Some or all of the operations and calculations performed by the additive supply amount determination device 50 or the control unit 40 described above may be performed manually.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these modes are combined as appropriate.

As used herein, expressions such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric" or "coaxial", etc. express relative or absolute arrangements. represents not only such arrangement strictly, but also the state of being relatively displaced with a tolerance or an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
Further, in this specification, expressions representing shapes such as a quadrilateral shape and a cylindrical shape not only represent shapes such as a quadrilateral shape and a cylindrical shape in a geometrically strict sense, but also within the range in which the same effect can be obtained. , a shape including an uneven portion, a chamfered portion, and the like.
Moreover, in this specification, the expressions “comprising”, “including”, or “having” one component are not exclusive expressions excluding the presence of other components.

1 Combustion facility 2 Boiler 4 Flue 5 Exhaust passage 6 Chimney 8 Fuel supply unit 10 Air supply unit 12 Combustion furnace 14 Heat transfer tube 16 Temperature reduction unit 18 Capture unit 20 Discharge pipe 21 Discharge valve 22 Fan 26 Detection unit 28 Additive supply unit 29 Additive supply line 30A First tank 30B Second tank 32A First supply pump 32B Second supply pump 34A First supply valve 34B Second supply valve 36 Temperature sensor 38 Concentration sensor 40 Control unit 42 Addition amount determination unit 44 Temperature control Part 46 Estimation part 48 Additive preparation part 50 Additive supply amount determination device

Claims (10)

An additive supply determination device for a combustion facility for burning a fuel containing heavy metals, comprising:
a detector configured to detect at least the content of heavy metals in ash produced by combustion of said fuel;
an addition amount determination unit configured to determine an addition amount of sulfur contained in an additive to be supplied to the fuel based on the detected heavy metal content ;
The detection unit is configured to detect the content of alkali metals in the ash and the content of alkaline earth metals in the ash,
The addition amount determination unit adds sulfur contained in the additive supplied to the fuel based on the detected heavy metal content, the alkali metal content, and the alkaline earth metal content. configured to determine the amount
Additive supply amount determination device. The detection unit is configured to detect at least the contents of calcium, sodium, potassium, zinc and lead in ash generated by combustion of the fuel,
The addition amount determination unit determines the number of moles m _Ca , m _Na , m _K , and m _Zn of calcium, sodium, potassium, zinc, and lead contained per unit weight of the fuel, based on the detection result of the detection unit. and m _Pb , and the number of moles m _S of sulfur contained in the additive added per unit weight of the fuel satisfies the following formula (A), so that the amount of the additive to be added is determined 2. The additive supply amount determination device according to claim 1, which is configured.
0.95≦ _mS /( _mCa + _2mNa + _2mK + _mZn + _mPb ) (A) The detection unit is configured to detect at least the contents of calcium, sodium, potassium, zinc and lead in ash generated by combustion of the fuel,
The addition amount determination unit determines the number of moles m _Ca , m _Na , m _K , and m _Zn of calcium, sodium, potassium, zinc, and lead contained per unit weight of the fuel, based on the detection result of the detection unit. and m _Pb , and the number of moles m _S of sulfur contained in the additive added per unit weight of the fuel satisfies the following formula (B), so that the amount of the additive to be added is determined 3. The additive supply amount determining device according to claim 1 or 2 .
_mS /( _mCa + _2mNa + _2mK + _mZn + _mPb )≤1.05 (B) A temperature adjustment unit for adjusting the combustion temperature of the fuel,
The detection unit is configured to detect at least zinc and lead contents in ash produced by combustion of the fuel,
The temperature adjustment unit is configured to adjust the combustion temperature to 950° C. or higher,
Based on at least the result of detection by the detection unit, the addition amount determination unit determines the number of moles m _Zn and m _Pb of zinc and lead contained per unit weight of the fuel, and sodium contained per unit weight of the fuel. and potassium, the number of moles _{mNa_vol} and _{mK_vol} of sodium and potassium volatilized during combustion of the fuel, and the number of moles _mS of sulfur contained in the additive added per unit weight of the fuel are as follows: The additive supply amount determination device according to any one of claims 1 to 3 , configured to determine the addition amount of the additive so as to satisfy the formula (C).
0.95≦ _mS /( _{2mNa_vol} + _{2mK_vol} + _mZn + _mPb )≦1.05 (C) Based on the temperature of the combustion gas generated by combustion of the fuel, the chlorine concentration in the combustion gas, and the weight ratio of chlorine and sulfur contained in the combustion gas, the number of moles of the volatilized sodium m _{Na_vol} and The additive supply amount determination device according to claim 4 , further comprising an estimation unit configured to estimate the number of moles _{mK_vol} of the volatilized potassium. Adjusting the molar ratio of sulfur contained in the additive added to the fuel and ammonia that may be generated from the additive based on the concentration of nitric oxide in the combustion gas produced by combustion of the fuel. 6. The additive supply amount determination device according to any one of claims 1 to 5 , further comprising an additive preparation section configured to be capable of supplying the additive. The additive preparation unit selects one or more sulfur-containing substances to be used as the additive from a plurality of sulfur-containing substances having different amounts of ammonia generated per molecule, and extracts the one or more sulfur-containing substances. 7. The additive supply determination device of claim 6 , configured to determine the content in each said additive. The additive preparation unit sets the number of moles of sulfur contained in the additive added per unit weight of the fuel to _mS , and the unit of the fuel converted from the concentration of nitrogen monoxide in the combustion gas When n _NO is the number of moles of nitric oxide generated per weight,
ammonium sulfate is used as said additive when _nNO is greater than twice _mS ,
ammonium hydrogen sulfate is used as the additive when _nNO is greater than 1 and no more than 2 times _mS ,
8. The additive supply amount according to claim 6 or 7 , configured to determine to use a sulfur-containing substance that does not contain ammonium ions as the additive when _nNO is less than or equal to 1 times _mS . decision device. Combustion equipment for burning fuel containing heavy metals,
a flue through which combustion gas generated by combustion of the fuel flows;
a heat transfer tube provided in the flue;
a capturing part provided downstream of the heat transfer tube in the flue for capturing the ash entrained in the combustion gas;
an additive supply configured to add a sulfur-containing additive to the fuel before or during combustion;
An additive supply amount determination device according to any one of claims 1 to 8 ,
The combustion equipment, wherein the detection unit is configured to detect the content of heavy metals in the ash captured by the capture unit. A method of operating a combustion facility for burning a fuel containing heavy metals, comprising:
a detection step of detecting the content of heavy metals in at least the ash produced by combustion of said fuel;
an addition amount determination step of determining the addition amount of sulfur contained in the additive supplied to the fuel based on the content of the heavy metal detected in the detection step;
with
In the detection step, the content of alkali metals in the ash and the content of alkaline earth metals in the ash are detected;
In the additive amount determination step, based on the content of the heavy metal, the content of the alkali metal, and the content of the alkaline earth metal detected in the detection step, determine the amount of added sulfur
Method of operating combustion equipment.

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