Combustion equipment

Abstract

To provide a combustion facility that has an improved effect of suppressing corrosion caused by corrosive compounds in a fuel combusted in a combustion device.SOLUTION: A combustion facility comprises: a combustion device for combusting a fuel that contains a chlorine element; a supply device for supplying a sulfur-containing additive to the combustion device; a regulation device for regulating a supply amount of the sulfur-containing additive by the supply device; and a detection device for detecting an amount of the chlorine element in a combustion gas generated by combustion of the fuel in the combustion device. The regulation device regulates the supply amount so that FS / FCl becomes in a predetermined range, where a detection value by the detection device is FCl and a supply amount of sulfur supplied to the combustion device by the supply device that supplies the sulfur-containing additive to the combustion device is FS.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to combustion equipment. [Background technology]

[0002] Patent Document 1 describes a combustion facility that supplies an additive (sulfur-containing additive) to fuel and burns it in order to suppress corrosion caused by heavy metals contained in the fuel. In this combustion facility, the content of heavy metals in ash generated by the combustion of fuel containing heavy metals is detected, and the amount of sulfur to be added to the additive supplied to the fuel is determined based on the detected value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-1701 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the combustion equipment described in Patent Document 1, the ash obtained by burning fuel is analyzed to measure the heavy metal content in the ash, and the amount of sulfur to be added to the additive supplied to the fuel is determined based on the measurement results. Therefore, if the heavy metal content in the fuel fluctuates, the amount of sulfur to be added cannot be adjusted quickly to respond to the fluctuation in the heavy metal content in the fuel, resulting in a problem of a reduced corrosion suppression effect.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide combustion equipment that has an improved effect of suppressing corrosion caused by corrosive compounds in fuel burned in a combustion device. [Means for solving the problem]

[0006] In order to achieve the above object, the combustion equipment according to the present disclosure includes a combustion device that burns a fuel containing chlorine element, a supply device that supplies a sulfur-containing additive to the combustion device, an adjustment device that adjusts the amount of the sulfur-containing additive supplied by the supply device, and a detection device that detects the amount of chlorine element in the combustion gas generated by the combustion of the fuel in the combustion device, and the value detected by the detection device is expressed as F Cl and the supply amount of sulfur supplied to the combustion device by the supply device supplying the sulfur-containing additive to the combustion device is F S Then, F S / F Cl The adjusting device adjusts the supply amount so that The range is determined based on the results of a chemical thermodynamic calculation, in which the amount of each element in the feed input to the combustion device is used as an input, calculations are performed to minimize the Gibbs free energy of the entire system of the combustion device, the amount and composition of each compound and each solution phase are output, and calculations are performed by parametrically changing the sulfur and chlorine supplied to the combustion device. . [Effects of the Invention]

[0007] According to the combustion equipment of the present disclosure, the supply amount of the sulfur-containing additive is adjusted based on the amount of chlorine element in the combustion gas generated by the combustion of fuel in the combustion device, so that the supply amount of the sulfur-containing additive can be quickly adjusted in response to changes in the behavior of the corrosive compounds in the fuel, thereby improving the effect of suppressing corrosion caused by the corrosive compounds in the fuel. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating the configuration of a combustion facility according to an embodiment of the present disclosure. FIG. [Figure 2] FIG. 1 is a diagram illustrating an outline of chemical thermodynamic calculation. [Figure 3] This is an example of the results of chemical thermodynamic calculations. [Figure 4] Another example of the results from chemical thermodynamic calculations. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a combustion facility according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment described below shows one aspect of the present disclosure, and does not limit the present disclosure. The embodiment can be arbitrarily modified within the scope of the technical concept of the present disclosure.

[0010] <Configuration of combustion equipment according to one embodiment of the present disclosure> As shown in FIG. 1 , a combustion facility 1 according to one embodiment of the present disclosure includes a boiler 2a serving as a combustion device 2, a supply device 3 for supplying a sulfur-containing additive to the boiler 2a, an adjustment device 4 for adjusting the amount of sulfur-containing additive supplied by the supply device 3, and a detection device 5 for detecting the amount of chlorine in the combustion gas generated by the combustion of fuel in the combustion device 2.

[0011] The fuel burned in the boiler 2a is not particularly limited, and any fuel containing chlorine may be used. In the following embodiment, the configuration and operation of the combustion equipment 1 will be described assuming that the boiler 2a is a waste-based fuel-fired boiler that uses waste containing chlorine as fuel. The boiler 2a includes a combustion furnace 11 in which fuel is burned, a flue 12 through which combustion gas generated in the combustion furnace 11 flows, a heat transfer tube 13 provided in the flue 12, and a hopper 14 for supplying fuel to the combustion furnace 11.

[0012] The configuration of the supply device 3 is not particularly limited. For example, the supply device 3 may include a tank 21 for storing the sulfur-containing additive, a supply line 22 connecting the tank 21 to the hopper 14, and a supply pump 23 provided on the supply line 22. The downstream end of the supply line 22 is connected to the hopper 14, but it may also be connected to the combustion furnace 11 so that the sulfur-containing additive can be directly supplied into the combustion furnace 11. The supply device 3 is not limited to having only one tank 21 and may have two or more tanks. In this case, each tank may store the same type of sulfur-containing additive, or different types of sulfur-containing additives. Separate supply lines 22 may be provided connecting each tank to the hopper 14 or the combustion furnace 11, or supply lines extending from each tank toward the hopper 14 or the combustion furnace 11 may join together and then connect to the hopper 14 or the combustion furnace 11. In the latter configuration, a switching device (for example, a switching valve or the like) for switching communication between any of the tanks and the hopper 14 or the combustion furnace 11 may be provided.

[0013] The configuration of the adjusting device 4 is not particularly limited, but for example, an adjusting device 4 including a bypass line 24 bypassing the supply pump 23, a flow control valve 25 provided in the bypass line 24, and a flow sensor 26 provided in the supply line 22 downstream of the bypass line 24 can be used. In this configuration, the opening of the flow control valve 25 is controlled so that the value detected by the flow sensor 26 becomes a set value, thereby returning a portion of the sulfur-containing additive discharged by the supply pump 23 to the upstream side of the supply pump 23, thereby adjusting the supply amount of the sulfur-containing additive supplied to the boiler 2a. As an alternative configuration, although not shown, a device for changing the discharge amount of the supply pump 23 may be used as the adjusting device 4 as long as the supply pump 23 is configured to have an adjustable discharge amount.

[0014] Since a high content of chlorine element in fuel is one of the causes of corrosion of the heat transfer tubes 13, etc., it is preferable to use the detection device 5 as a device that detects the amount of chlorine element in fuel by detecting the amount of hydrogen chloride in the combustion gas. However, the detection device 5 is not limited to a hydrogen chloride meter or the like that detects the amount of hydrogen chloride, and may be an instrument that directly measures the amount of chlorine element, such as a gas chromatograph mass spectrometer.

[0015] The combustion equipment 1 may include a control device 6 to which the detection device 5, the flow control valve 25, and the flow sensor 26 are electrically connected. The combustion equipment 1 may also include an exhaust line 8 that connects the flue 12 and the chimney 7, and a fan 9 provided in the exhaust line 8.

[0016] <Operation of combustion equipment according to one embodiment of the present disclosure> Next, the operation of the combustion equipment 1 according to one embodiment of the present disclosure will be described. Waste as fuel is supplied to the combustion furnace 11 via the hopper 14. Furthermore, by driving the supply pump 23, the sulfur-containing additive stored in the tank 21 is supplied to the hopper 14 via the supply line 22. In this way, the sulfur-containing additive and the waste are supplied to the combustion furnace 11. In the combustion furnace 11, the waste mixed with the sulfur-containing additive is combusted.

[0017] Combustion gas generated by burning waste in the combustion furnace 11 flows out of the combustion furnace 11 when the fan 9 is driven, and flows through the flue 12. As the combustion gas flows through the flue 12, it exchanges heat with a fluid (such as water) flowing inside the heat transfer tubes 13, thereby heating the fluid and cooling the combustion gas. The heated fluid can be used, for example, as steam to drive a power generation turbine (not shown). The combustion gas that has heated the fluid flows sequentially through the flue 12 and exhaust line 8, and is released into the atmosphere via the chimney 7.

[0018] During the above operation, the detector 5 measures the amount of chlorine element (mass flow rate) F Cland transmits the detection result to the control device 6. The control device 6 is provided with a mass ratio F S / F Cl The range of F is preset. S is the supply amount (mass flow rate) of sulfur supplied to the combustion device 2 by the supply device 3 supplying the sulfur-containing additive to the combustion device 2. Since the sulfur content of the sulfur-containing additive stored in the tank 21 is known, F S / F Cl The adjusting device 4 can adjust the supply amount of the sulfur-containing additive so that the amount of sulfur-containing additive falls within a predetermined range.

[0019] F S / F Cl The range of F can be determined in advance by calculation, experiment, etc. The method of determining it by calculation will be described later. In order to suppress corrosion caused by ash in the combustion gas that adheres to the heat transfer tube 13, etc., S / F Cl It is preferable that the ratio is >0.3, and in order to prevent ash in the combustion gas from adhering to the heat transfer tube 13, etc., it is preferable that the ratio is 0.6 <F S / F Cl It is preferable to set it to <1.0.

[0020] In this way, in the combustion equipment 1, by adjusting the supply amount of the sulfur-containing additive based on the amount of chlorine element in the combustion gas generated by the combustion of fuel in the combustion device 2, the supply amount of the sulfur-containing additive can be quickly adjusted in response to changes in the behavior of the corrosive compounds in the fuel, thereby improving the effect of suppressing corrosion caused by the corrosive compounds in the fuel.

[0021] <F S / F Cl Calculation method for determining the range > As explained in the operation of the combustion equipment 1, the combustion gas flowing through the flue 12 is cooled by heat exchange with the fluid flowing inside the heat transfer tubes 13, and as a result, ash in the combustion gas may precipitate and adhere to the heat transfer tubes 13, etc., potentially corroding them. If the fuel burned in the combustion device 2 contains chlorine elements, the ash that adheres to the heat transfer tubes 13 will also contain chlorine elements. In such cases, according to studies by the inventors of the present disclosure, corrosion occurs through the following two mechanisms.

[0022] Mechanism 1: Reaction with molten salt in the attached ash The corrosion reaction caused by molten salt is an electrochemical reaction, and causes corrosion (oxidation of iron) through the following reactions (A) to (C). Fe(solid) → Fe 2+ (molten salt) + 2e - (A) O2 (air) + 4e - →2O 2- (Molten salt) (B) 2Fe 2+ +2O 2- (molten salt) → 2FeO(solid) (C)

[0023] Mechanism 2: Reaction with chlorine compounds in the deposited ash Chlorine gas is generated by the reaction (D) below between the chlorine in the attached ash and the sulfur dioxide in the combustion gas, and the chlorine gas causes corrosion (oxidation of iron) as shown in the following reactions (E) and (F). 2NaCl+SO2+O2→Cl2+Na2SO4...(D) Fe(solid) + Cl2(gas) → FeCl2(solid / liquid) (E) 3FeCl2(solid / liquid) + 2O2(gas) → Fe3O4(solid) + 3Cl2 (F)

[0024] The inventors of the present disclosure performed chemical thermodynamic calculations to predict the generation behavior of molten salts, which are key to ash adhesion and corrosion. As shown in Figure 2, the chemical thermodynamic calculation uses a database of Gibbs free energy information for each compound and each solution phase, and inputs the amounts of each element in the fuel, additives, air, and other feeds fed into the combustion furnace 11 (see Figure 1) (Figure 2(1)). Calculations are performed to minimize the Gibbs free energy of the entire system in the combustion furnace 11 (Figure 2(2)), and the amounts and compositions of each compound and each solution phase are output (Figure 2(3)). Here, each compound is a pure compound in the gas, liquid, or solid phase. A solution phase, like a molten salt or solid solution, has a non-stoichiometric ratio of the constituent elements, with molten salts being the liquid phase and solid solutions being the solid phase. By performing calculations that parametrically change the inputs to the calculations, i.e., the S and Cl elements fed into the combustion furnace 11, the F S / F Cl The value has changed.

[0025] By such chemical thermodynamic calculations, F S / F Cl and O in the output liquid phase 2- The relationship between the amount of molten salt and the basicity (pO 2- ) is known to affect pO 2- It has been reported that the dissolution rate of the protective film increases in the high basicity range, such as <5 (see T. Ishitsuka, K. Nose, Corrosion Science 44 / 2002 / 247-263). S / F Cl >0.3, in the temperature range of 350 to 550°C, 2- ≧5, it is thought that the dissolution rate of the protective film can be kept low. S / F Cl By maintaining the condition of >0.3, corrosion caused by molten salt in the adhering ash can be suppressed.

[0026] Furthermore, by such chemical thermodynamic calculations, F S / F ClThe relationship between the melting rate of ash and the melting rate of ash is shown in Figure 4. <F S / F Cl <1, in the temperature range of 350 to 550°C, 0.6 ≥ F S / F Cl and F S / F Cl The melting rate of ash can be kept low compared to the range of 0.6 <F S / F Cl By maintaining the condition of <1, ash adhesion can be suppressed.

[0027] The contents described in each of the above embodiments can be understood, for example, as follows.

[0028] [1] The combustion equipment according to one aspect includes: a combustion device (2) that burns fuel containing elemental chlorine; a supply device (3) for supplying a sulfur-containing additive to the combustion device (2); an adjusting device (4) for adjusting the amount of the sulfur-containing additive supplied by the supply device (3); a detector (5) for detecting the amount of chlorine element in the combustion gas generated by the combustion of the fuel in the combustion device (2); Equipped with The value detected by the detector (5) is F Cl and the supply amount of sulfur supplied to the combustion device (2) by the supply device (3) supplying the sulfur-containing additive to the combustion device (2) is F S Then, F S / F Cl The adjusting device (4) adjusts the supply amount so that the amount of the supplied water falls within a predetermined range.

[0029] According to the combustion equipment of the present disclosure, the supply amount of the sulfur-containing additive is adjusted based on the amount of chlorine element in the combustion gas generated by the combustion of fuel in the combustion device, so that the supply amount of the sulfur-containing additive can be quickly adjusted in response to changes in the behavior of the corrosive compounds in the fuel, thereby improving the effect of suppressing corrosion caused by the corrosive compounds in the fuel.

[0030] [2] The combustion equipment according to another aspect is the combustion equipment of [1], The range is F S / F Cl >0.3.

[0031] With this configuration, corrosion caused by ash in the combustion gas that adheres to the heat transfer tubes and the like can be suppressed.

[0032] [3] A combustion facility according to yet another embodiment is the combustion facility of [1] or [2], The range is 0.6 <F S / F Cl <1.0.

[0033] With this configuration, it is possible to prevent ash in the combustion gas from adhering to the heat transfer tubes and the like.

[0034] [4] A combustion facility according to yet another embodiment is the combustion facility according to any one of [1] to [3], The range is determined based on the results of chemical thermodynamic calculations, The chemical thermodynamic calculation uses the amount of each element in the feed input to the combustion device (2) as an input, calculates to minimize the Gibbs free energy of the entire system of the combustion device (2), outputs the amount and composition of each compound and each solution phase, and performs a calculation while parametrically changing the sulfur and chlorine supplied to the combustion device (2).

[0035] With this configuration, F S / F Cl The range of can be determined. [Explanation of symbols]

[0036] 1 Combustion equipment 2 Combustion equipment 3 Feeding device 4 Adjustment device 5. Detection equipment

Claims

1. a combustion device that burns fuel containing elemental chlorine; a supply device for supplying a sulfur-containing additive to the combustion device; an adjusting device for adjusting the amount of the sulfur-containing additive supplied by the supply device; a detector for detecting the amount of chlorine element in the combustion gas generated by the combustion of the fuel in the combustion device; Equipped with The detection value by the detection device is F Ｃｌ and the supply amount of sulfur supplied to the combustion device by the supply device supplying the sulfur-containing additive to the combustion device is F Ｓ Then, F Ｓ / F Ｃｌ the adjusting device adjusts the supply amount so that the amount is within a predetermined range; The range is determined based on the results of chemical thermodynamic calculations, The chemical thermodynamic calculation uses the amount of each element in the feed input to the combustion device as an input, calculates to minimize the Gibbs free energy of the entire system of the combustion device, outputs the amount and composition of each compound and each solution phase, and performs a calculation by parametrically changing the sulfur and chlorine supplied to the combustion device.

2. The range is F Ｓ / F Ｃｌ The combustion facility according to claim 1, wherein the ratio of the stoichiometric ...

3. The range is 0.6<F Ｓ / F Ｃｌ 3. The combustion installation according to claim 1 or 2, wherein the ρ is < 1.0.

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