Manufacturing methods for power generation-related equipment

Abstract

The present invention provides a method for manufacturing power generation-related equipment that can easily achieve both corrosion prevention and high-efficiency heat exchange. [Solution] The power generation equipment according to the embodiment includes a wall portion having a first surface through which a first medium containing corrosive components flows and corrosion occurs due to the corrosive components, and a second surface through which a second medium flows, and heat exchange between the first medium and the second medium is performed through the wall portion. In the manufacturing method of the power generation equipment, the distribution of corrosion risk levels due to corrosive components on the first surface is determined, the distribution of heat exchange efficiency requirements required for heat exchange in the wall portion is determined, and a coating layer is applied to the first surface. The coating layer is applied by changing the thickness of the coating layer according to the corrosion risk level and the heat exchange efficiency requirements.

Description

Technical Field

[0001] Embodiments of the present invention relate to a method for manufacturing power generation-related equipment.

Background Art

[0002] A combined cycle power generation plant includes a gas turbine and a steam turbine, and is configured to generate power by driving the gas turbine and the steam turbine. Specifically, in a combined cycle power generation plant, the gas turbine is driven by introducing combustion gas. Then, steam is generated in an exhaust heat recovery boiler using the heat of the combustion exhaust gas discharged from the gas turbine, and the steam turbine is driven by introducing the steam generated in the exhaust heat recovery boiler.

[0003] The exhaust heat recovery boiler includes, for example, heat transfer tubes, and heat exchange is performed between the water (such as hot water) flowing inside the heat transfer tubes and the combustion exhaust gas flowing outside the heat transfer tubes, thereby generating steam to be introduced into the steam turbine.

[0004] The heat transfer tubes constituting the exhaust heat recovery boiler may be corroded. For example, the components contained in the combustion exhaust gas act on the heat transfer tubes as corrosive components. As a result, due to the corrosion of the heat transfer tubes, the tube thickness of the heat transfer tubes becomes thinner, the durability decreases, and leakage may occur. In addition, due to the corrosion of the heat transfer tubes, a corrosion product layer may be provided on the surface of the heat transfer tubes, and the heat exchange efficiency may decrease. Therefore, a removal operation for removing foreign layers such as the corrosion product layer from the surface of the heat transfer tubes may be required, but it may be difficult to perform the removal operation for parts with a complicated structure. In the exhaust heat recovery boiler, corrosion may also occur in parts other than the heat transfer tubes (such as stub tubes, headers, etc.), and similar problems may occur.

[0005] In order to suppress the corrosion of parts such as heat transfer tubes, a technique of coating parts such as heat transfer tubes with a coating layer such as ceramics has been proposed.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Utility Model Publication No. 01-46690 [Patent Document 2] Japanese Patent Publication No. 2023-5910 [Patent Document 3] Japanese Patent Application Publication No. 11-311103 [Patent Document 4] Japanese Patent Publication No. 2004-283699 [Patent Document 5] Japanese Patent Publication No. 2011-163649 [Patent Document 6] Japanese Patent Publication No. 2004-211628 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In waste heat recovery boilers, components such as heat transfer tubes have areas that are prone to corrosion and areas that are not. Because the environment (e.g., temperature, humidity, pressure, flow rate of the fluid; presence or absence of corrosive components; presence or absence of adhering components) can vary depending on the installation location, the progression of corrosion may differ in different parts. For example, when a fluid containing sulfuric acid flows, corrosion is more likely to occur in areas below the sulfuric acid dew point than in areas above the dew point. Furthermore, corrosion is more likely to occur due to the heat applied during manufacturing processes such as welding. Therefore, if a coating layer of arbitrary thickness is applied to heat transfer tubes, the corrosion prevention function of the coating layer may not be fully effective.

[0008] Furthermore, in a heat recovery boiler, components such as heat transfer tubes have areas where heat exchange is likely to occur and areas where it is not. In components such as heat transfer tubes, the environment (e.g., temperature, humidity, pressure, flow rate of the medium; presence or absence of corrosive components; presence or absence of adhering components) may differ depending on the installation location, so the heat exchange efficiency may differ in each part. For example, in areas where corrosion is likely to occur, a thick layer of corrosive material is formed, which may reduce the heat exchange efficiency. In addition, for example, in areas where a large amount of medium containing adhering components flows, the adhering layer will be thicker than in areas where a small amount of medium containing adhering components flows, which may result in insufficient heat exchange due to the adhering layer. For this reason, if a coating layer of an arbitrary thickness is provided on heat transfer tubes, the coating layer may prevent them from fully performing their heat exchange function.

[0009] Similar malfunctions can occur in other power generation-related equipment that make up a power plant, in addition to the heat recovery boiler. For example, similar malfunctions can occur in the flue (chimney) through which the combustion exhaust gas discharged from the heat recovery boiler flows.

[0010] Due to the circumstances described above, it has traditionally been difficult to easily achieve both corrosion suppression and high-efficiency heat exchange in power generation equipment such as waste heat recovery boilers.

[0011] Therefore, the problem that the present invention aims to solve is to provide a method for manufacturing power generation-related equipment that can easily achieve both the suppression of corrosion and the high efficiency of heat exchange. [Means for solving the problem]

[0012] The power generation equipment according to the embodiment includes a wall portion having a first surface through which a first medium containing corrosive components flows and corrosion occurs due to the corrosive components, and a second surface through which a second medium flows, and heat exchange between the first medium and the second medium is performed through the wall portion. The manufacturing method of the power generation equipment according to the embodiment includes one or more steps of a corrosion risk level acquisition step, a heat exchange efficiency requirement level acquisition step, and a coating step. In the corrosion risk level acquisition step, the distribution of corrosion risk levels at which corrosion occurs due to corrosive components on the first surface is determined. In the heat exchange efficiency requirement level acquisition step, the distribution of heat exchange efficiency requirement levels required for heat exchange on the wall portion is determined. In the coating step, a coating layer is applied to the first surface. In the coating step, the thickness of the coating layer is changed according to the corrosion risk level and / or heat exchange efficiency requirement level, and the coating layer is applied. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a method for manufacturing power generation-related equipment that can easily achieve both the suppression of corrosion and the high efficiency of heat exchange. [Brief explanation of the drawing]

[0014] [Figure 1A] Figure 1A is a schematic partial cross-sectional view showing the main components of a waste heat recovery boiler, which is a power generation-related device, in an embodiment. [Figure 1B] Figure 1B is a schematic partial cross-sectional view showing the main components of a waste heat recovery boiler, which is a power generation-related device, in an embodiment. [Figure 1C] Figure 1C is a magnified view of a portion of the heat transfer tube 21 of a heat recovery boiler, which is a power generation-related device, in an embodiment. [Figure 2] Figure 2 is a flowchart showing a method for manufacturing power generation-related equipment according to an embodiment. [Figure 3] Figure 3 is a magnified view of a portion of the heat transfer tube 21 of a heat recovery boiler, which is a power generation-related device, in an embodiment. [Figure 4]FIG. 4 is a diagram showing an enlarged part of a heat transfer tube 21 of an exhaust heat recovery boiler which is power generation related equipment in Modification 1. [Figure 5A] FIG. 5A is a diagram for explaining a process of manufacturing an exhaust heat recovery boiler which is power generation related equipment in Modification 2. [Figure 5B] FIG. 5B is a diagram for explaining a process of manufacturing an exhaust heat recovery boiler which is power generation related equipment in Modification 2. [Figure 5C] FIG. 5C is a diagram for explaining a process of manufacturing an exhaust heat recovery boiler which is power generation related equipment in Modification 2.

MODE FOR CARRYING OUT THE INVENTION

[0015] [A] Configuration of Exhaust Heat Recovery Boiler The configuration of an exhaust heat recovery boiler manufactured as power generation related equipment by the manufacturing method according to the embodiment will be described.

[0016] FIGS. 1A and 1B are partial cross-sectional views schematically showing main parts of the configuration of an exhaust heat recovery boiler which is power generation related equipment in the embodiment. In FIG. 1A, an xz plane defined by the x direction and the z direction is illustrated, and in FIG. 1B, a yz plane defined by the y direction and the z direction is illustrated.

[0017] As shown in FIGS. 1A and 1B, the exhaust heat recovery boiler has a container 20 and a heat transfer tube 21.

[0018] [A-1] Container 20 In the exhaust heat recovery boiler, the container 20 is formed of, for example, a metal material, and includes an inlet through which a first medium F1 is introduced from the outside to the inside and an outlet through which the first medium F1 is discharged from the inside to the outside. Here, in the container 20, the inlet and the outlet are arranged, for example, in the x direction.

[0019] [A-2] Heat Transfer Tube 21 In a waste heat recovery boiler, the heat transfer tube 21 is, for example, a cylindrical tube. The heat transfer tube 21 is made of a metallic material containing at least one component of, for example, Fe, Al, Zn, Cu, Ni, or Cr, taking into consideration various functions such as heat transfer performance, mechanical strength, and corrosion resistance.

[0020] The heat transfer tube 21 includes an inlet through which the second medium F2 is introduced from the outside into the interior, and an outlet through which the second medium F2 is discharged from the interior to the outside. The heat transfer tube 21 extends in the container 20 such that its axis lies along the y-direction, which is perpendicular to the x-direction in which the inlet and outlet are aligned.

[0021] Here, there are multiple heat transfer tubes 21. The multiple heat transfer tubes 21 are arranged in the x-direction, where the inlet and outlet are aligned in the container 20. Furthermore, the multiple heat transfer tubes 21 are also arranged in the y-direction, which is perpendicular to both the x-direction, where the inlet and outlet are aligned in the container 20, and the z-direction, where the inlet and outlet are aligned in the heat transfer tubes 21. The multiple heat transfer tubes 21 aligned in the y-direction have a header 221 on the inlet side and a header 222 on the outlet side.

[0022] Figure 1C is a magnified view of a portion of the heat transfer tube 21 of a heat recovery boiler, which is a power generation-related device, in an embodiment. In Figure 1C, the xz plane is shown, similar to Figure 1A.

[0023] As shown in Figure 1C, the heat transfer tube 21 includes a heat transfer tube body 210 and fins 212, with a plurality of fins 212 provided on the outer circumferential surface of the heat transfer tube body 210. Each of the plurality of fins 212 is, for example, ring-shaped and protrudes outward from the outer circumferential surface of the heat transfer tube body 210. The plurality of fins 212 are arranged, for example, in a direction perpendicular to both the direction in which the inlet and outlet of the heat transfer tube 21 are aligned, with space between them.

[0024] In a waste heat recovery boiler, the first medium F1 is, for example, combustion exhaust gas discharged from a gas turbine (not shown) that constitutes a combined cycle power plant, and flows in the container 20 along the x-direction where the inlet and outlet are aligned.

[0025] In a waste heat recovery boiler, the second medium F2 is introduced into the heat transfer tubes 21 as condensed water after being exhausted from, for example, a steam turbine (not shown) that constitutes a combined cycle power plant and condensed in a condenser, and flows along the z-direction where the inlet and outlet are aligned in the heat transfer tubes 21. Here, the second medium F2 is introduced from the header 221 into each of the multiple heat transfer tubes 21, and then flows from each of the multiple heat transfer tubes 21 to the header 222.

[0026] In the heat transfer tube 21, heat exchange takes place between the first medium F1 and the second medium F2. Specifically, the heat exchange is performed by transferring heat from the first medium F1 flowing on the outside to the second medium F2 flowing inside through a wall portion of the heat transfer tube 21, which includes the outer surface S1 (first surface) of the first medium F1 that contacts the heat transfer tube body 210 and the fins 212, and the inner surface S2 (second surface) of the heat transfer tube body 210 that contacts the second medium F2. As a result, for example, the second medium F2, which is condensed water, is heated by the first medium F1, which is combustion exhaust gas, and turns into steam. The steam of the second medium F2 is then discharged from the heat transfer tube 21 to, for example, a steam turbine (not shown).

[0027] Here, the first medium F1, which is the combustion exhaust gas, contains corrosive components that corrode the heat transfer tube 21, and adhesive components that adhere to the heat transfer tube 21. As a result, the outer surface S1 (first surface) of the heat transfer tube 21 may be corroded by the corrosive components contained in the first medium F1, and a corrosive layer (not shown) may be formed on the outer surface S1 (first surface). In addition, an adhesive layer (not shown) may be formed on the outer surface S1 (first surface) due to the adhesive components contained in the first medium F1.

[0028] The corrosive component is, for example, at least one of the components listed below, and is at least one of a gas, a liquid, and a solid. • Ionic components: Hydrogen ions, hydroxide ions, hydrochloride ions, nitrate ions, sulfate ions, hydrogen sulfide ions, chloride ions, carbonate ions, ammonium ions Salts: hydroxide salts, hydrochloride salts, nitrates, sulfates, chloride salts, carbonates, ammonium salts

[0029] [B] Manufacturing method A method for manufacturing power generation-related equipment according to an embodiment will be described.

[0030] Figure 2 is a flowchart showing a method for manufacturing power generation-related equipment according to an embodiment.

[0031] Figure 2 illustrates the process of applying a coating layer (not shown in Figures 1A and 1B) to the heat transfer tubes 21 of the waste heat recovery boiler, which is shown as power generation-related equipment in Figures 1A and 1B.

[0032] [B-1] Corrosion risk level acquisition process (ST10) As shown in Figure 2, first, the corrosion risk level LX is obtained (ST10).

[0033] Here, we determine the distribution of corrosion risk level LX on the outer surface S1 (first surface) of the heat transfer tube 21 (see Figure 1A, etc.) that constitutes the waste heat recovery boiler, where corrosion occurs due to corrosive components in the first medium F1. The corrosion risk level LX is a value indicating the degree of corrosion and is determined for each part of the outer surface S1 of the heat transfer tube 21 based on corrosion factors that affect corrosion. The distribution of corrosion risk level LX can be determined, for example, using a simulator that uses design values ​​or assumed values. In addition, methods may be used in which appropriate test pieces are installed and removed from the equipment, or a portion is taken from the equipment, and the corrosion risk level is calculated from the resulting values ​​and corrosion status. This also includes determination from visual inspection and non-destructive testing.

[0034] The corrosion risk level LX can be determined by considering corrosion factors when a heat recovery boiler is installed and in usable condition at a power plant, or by considering other conditions under which corrosion may occur. For example, it can be determined by considering various conditions under which the heat recovery boiler is manufactured (material manufacturing process, component manufacturing process, assembly process, joining process, etc.), transported, and repaired.

[0035] The corrosion risk level LX is determined based on the corrosion factors in the environment to which the heat transfer tubes 21 constituting the waste heat recovery boiler are exposed. Corrosion factors in the environment include, for example, the ambient temperature (temperature of the operating environment, etc.), the type and amount of corrosive components (including reducing components) contained in the environment, the type and amount of corrosion-promoting components (such as moisture) contained in the environment, and the flow rate and pressure of the medium containing the corrosive components. If the temperature of the operating environment is outside the reference temperature range, the corrosion risk level LX will increase. If a large amount of corrosive components in the environment act on the heat transfer tubes 21, the corrosion risk level LX will increase. If there are many corrosion-promoting components in the environment, the reaction between the corrosive components and the material components constituting the heat transfer tubes 21 is promoted, thus increasing the corrosion risk level LX. If the flow rate and pressure of the medium containing corrosive components are high, the corrosion risk level LX will increase.

[0036] Furthermore, the corrosion risk level LX is determined based on corrosion factors related to the material properties of the heat transfer tubes 21 that constitute the waste heat recovery boiler. Corrosion factors related to material properties include, for example, the corrosion resistance of the material (including variations due to welding, etc.). As the corrosion resistance of the material constituting the heat transfer tubes 21 decreases, the corrosion risk level LX increases. In addition, corrosion is more likely to occur due to the effects of heat applied during manufacturing processes such as welding, which also increases the corrosion risk level LX.

[0037] Furthermore, the corrosion risk level LX is determined based on corrosion factors related to the structure (shape, arrangement, etc.) of the heat transfer tubes 21 that constitute the waste heat recovery boiler. For example, the portion of the heat transfer tube 21 located upstream in the flow direction of the first medium F1 will have a higher corrosion risk level LX than the portion located downstream, because it will be hit by more corrosive and adhering components in the first medium F1. Also, the corrosion risk level LX will be higher in parts of the heat transfer tube 21 where corrosive components tend to accumulate (corners, recesses, etc.).

[0038] The corrosion risk level LX may be determined by considering the interaction of multiple corrosion factors. For example, when a medium containing sulfuric acid as a corrosive component flows, corrosion is more likely to occur in areas below the sulfuric acid dew point than in areas above the sulfuric acid dew point, resulting in a higher corrosion risk level LX.

[0039] [B-2] Process for obtaining the required level of heat exchange efficiency (ST20) Next, as shown in Figure 2, the heat exchange efficiency requirement level LY is obtained (ST20).

[0040] Here, we determine the distribution of the heat exchange efficiency requirement level LY required for heat exchange between the first medium F1 and the second medium F2 in the heat transfer tube 21 (see Figure 1A, etc.) that constitutes the waste heat recovery boiler. The heat exchange efficiency requirement level LY is a value relating to the degree to which the heat transfer function is performed, and is determined for each part of the outer surface S1 of the heat transfer tube 21 based on the heat exchange factors that affect the heat exchange efficiency. The distribution of the heat exchange efficiency requirement level LY can be determined, for example, using a simulator.

[0041] The required heat exchange efficiency level LY can be determined, for example, by calculating the heat exchange performance. This can be calculated by determining the total heat exchange amount Q, which is derived from the overall heat transfer coefficient U, the heat transfer area A, and the logarithmic mean temperature difference ΔTlm. For example, Q = U·AΔTlm.

[0042] Q: Total heat exchanged [W] U: Overall heat transfer coefficient [W / m 2 ·K] A: Heat transfer area [m²] 2 ] ΔTlm: Logarithmic mean temperature difference [K]

[0043] The overall heat transfer coefficient can be calculated, for example, using the following formula.

[0044]

number

[0045]

number

[0046] U: Overall heat transfer coefficient [W / m 2 ·K] T1: High temperature fluid temperature [℃] T2: Low temperature fluid temperature [℃] h1: Heat transfer coefficient of high-temperature fluids [W / m 2 ·K] h2: Heat transfer coefficient of low-temperature fluids [W / m 2 ·K] k: Thermal conductivity of the partition [W / m·K] δ: Thickness of partition [m] γ1: Fouling coefficient on the high-temperature fluid side [m 2 ·K / W] γ2: Fouling coefficient on the low-temperature fluid side [m 2 ·K / W]

[0047]

number

[0048] The above is just one example, but based on calculations like the one above, the overall heat transfer coefficient is calculated for the heat exchange performance required for the equipment, and the effect of the coating film is determined based on the thermal conductivity, which is indicated as k in the above formula.

[0049] [B-3] Coating process (ST30) Next, the coating layer is applied (ST30).

[0050] Here, a coating layer is applied to the outer surface S1 (first surface) of the heat transfer tube 21 (see Figure 1A, etc.) that constitutes the waste heat recovery boiler.

[0051] In this embodiment, the thickness of the coating layer is varied according to the corrosion risk level LX and the heat exchange efficiency requirement level LY, and the coating layer is applied accordingly.

[0052] For example, the thickness TX of the coating layer is determined based on the corrosion risk level LX, and the thickness TY of the coating layer is determined based on the heat exchange efficiency requirement level LY. Then, based on both thickness TX and thickness TY, the thickness TZ of the coating layer to be applied to the outer surface S1 of the heat transfer tube 21 in this process is determined. Finally, the coating layer is applied to achieve that thickness TZ.

[0053] We will now explain the details of this process step by step.

[0054] [B-3-1] Calculation of coating layer thickness TX based on corrosion risk level LX The thickness TX of the coating layer is required to increase as the corrosion risk level LX increases. For example, if the obtained corrosion risk level LX for each part of the outer surface S1 of the heat transfer tube 21 (see Figure 1A, etc.) is greater than the standard value for corrosion risk level LX, the thickness TX of the coating layer is required to be greater than the recommended thickness TXs set when the corrosion risk level LX is at the standard value.

[0055] In contrast, the thickness TX of the coating layer is required to decrease as the corrosion risk level LX decreases. For example, if the obtained corrosion risk level LX values ​​for each part of the outer surface S1 of the heat transfer tube 21 are smaller than the standard value for corrosion risk level LX, the thickness TX of the coating layer is required to be thinner than the recommended thickness TXs of the coating layer set when the corrosion risk level LX is at the standard value.

[0056] The thickness TX of the coating layer is varied according to the difference between the acquired corrosion risk level LX and the standard value of corrosion risk level LX.

[0057] In other words, if the acquired corrosion risk level LX is greater than the standard corrosion risk level LX, the thickness TX of the coating layer is set to increase as the difference between the acquired corrosion risk level LX and the standard corrosion risk level LX increases. On the other hand, if the acquired corrosion risk level LX is less than the standard corrosion risk level LX, the thickness TX of the coating layer is set to decrease as the difference between the acquired corrosion risk level LX and the standard corrosion risk level LX increases.

[0058] [B-3-2] Calculation of coating layer thickness TY based on heat exchange efficiency requirement level LY The calculation of the coating layer thickness TY based on the heat exchange efficiency requirement level LY will be explained separately for two cases: Case 1, when there is no foreign matter layer (adhered material layer, corrosive material layer) on the outer surface S1 of the heat transfer tube 21, and Case 2, when there is a foreign matter layer (adhered material layer, corrosive material layer) on the outer surface S1 of the heat transfer tube 21.

[0059] If there is no foreign matter layer (adhered material layer, corrosive material layer) on the outer surface S1 of the heat transfer tube 21 (Case 1), This includes cases where the heat transfer tube 21 is a new, unused unit, or where the heat transfer tube 21 is an existing unit but the foreign matter layer (adhered material layer, corrosive material layer) has been removed and is no longer present.

[0060] In contrast, in the case where a foreign matter layer (adhered material layer, corrosive material layer) exists on the outer surface S1 of the heat transfer tube 21 (Case 2), this includes cases where the heat transfer tube 21 is a new, unused tube but a foreign matter layer (adhered material layer, corrosive material layer) exists on the outer surface S1 due to some factor, cases where the heat transfer tube 21 is an existing product that has been used and the foreign matter layer (adhered material layer, corrosive material layer) has not been removed, and cases where the heat transfer tube 21 is an existing product that has been used and the foreign matter layer (adhered material layer, corrosive material layer) has been removed but the foreign matter layer (adhered material layer, corrosive material layer) remains.

[0061] [B-3-2-1] Case 1: When there is no foreign matter layer (adhered material layer, corrosive material layer) on the outer surface S1 of the heat transfer tube 21 When there is no foreign matter layer composed of at least one of the deposit layer and the corrosive layer on the outer surface S1 of the heat transfer tube 21 (see Fig. 1A, etc.) (Case 1), based on the relationship between the thermal conductivity A of the heat transfer tube 21 and the thermal conductivity B of the laminated structure formed by coating a coating layer on the outer surface S1 of the heat transfer tube 21, the thickness TY of the coating layer is changed according to the heat exchange efficiency requirement level LY.

[0062] [B-3-2-1-1] When A < B (Case 1-1) When the thermal conductivity A of the heat transfer tube 21 is lower than the thermal conductivity B of the laminated structure formed by coating a coating layer on the outer surface S1 of the heat transfer tube 21 (A < B; Case 1-1), as the heat exchange efficiency requirement level LY increases, the thickness TY of the coating layer is required to increase.

[0063] For example, when the acquired value of the heat exchange efficiency requirement level LY obtained for each part of the heat transfer tube 21 (see Fig. 1A, etc.) is greater than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer is required to be greater than the recommended thickness TYs of the coating layer set when the heat exchange efficiency requirement level LY is the reference value.

[0064] The thickness TY of the coating layer is varied according to the difference value between the acquired value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY. That is, when the acquired value of the heat exchange efficiency requirement level LY is greater than the reference value of the heat exchange efficiency requirement level LY, as the difference value between the acquired value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases, the thickness TY of the coating layer is required to increase. On the other hand, when the acquired value of the heat exchange efficiency requirement level LY is smaller than the reference value of the heat exchange efficiency requirement level LY, as the difference value between the acquired value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases, the thickness TY of the coating layer is required to decrease.

[0065] [B-3-2-1-2] When A > B (Case 1-2) When the thermal conductivity A of the heat transfer tube 21 is higher than the thermal conductivity B of the laminated structure formed by coating the outer surface S1 of the heat transfer tube 21 with a coating layer (A > B; Case 1-2), the thickness of the coating layer 30 is required to decrease as the required heat exchange efficiency level (LY) increases.

[0066] For example, if the obtained value of the heat exchange efficiency requirement level LY for each part of the heat transfer tube 21 (see Figure 1A, etc.) is greater than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer will be made thinner than the recommended thickness TYs set when the heat exchange efficiency requirement level LY is at the reference value.

[0067] The thickness TY of the coating layer is varied according to the difference between the obtained value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY. In other words, if the obtained value of the heat exchange efficiency requirement level LY is greater than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer is required to become thinner as the difference between the obtained value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases. On the other hand, if the obtained value of the heat exchange efficiency requirement level LY is smaller than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer is required to become thicker as the difference between the obtained value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases.

[0068] [B-3-2-2] Case 2: When a foreign matter layer (adhered material layer, corrosive material layer) is present on the outer surface S1 of the heat transfer tube 21 If a foreign matter layer consisting of at least one of an adhering layer and a corrosive layer is present on the outer surface S1 of the heat transfer tube 21 (see Figure 1A, etc.) (Case 2), the thickness TY of the coating layer is changed according to the required heat exchange efficiency level LY, based on the relationship between the thermal conductivity A of the heat transfer tube 21, the thermal conductivity B of the laminated structure formed by coating the outer surface S1 of the heat transfer tube 21 with a coating layer, the thermal conductivity C of the laminated structure formed by providing a foreign matter layer on the outer surface S1 of the heat transfer tube 21, and the thermal conductivity D of the laminated structure formed by providing a foreign matter layer on the outer surface S1 of the heat transfer tube 21 and coating the outer surface S1 of the heat transfer tube 21 with a coating layer via the foreign matter layer.

[0069] [B-3-2-2-1] When at least one of the relationships A < B, A < D, C < B, and C < D is satisfied (Case 2-1) When at least one of the relationships where the thermal conductivity A is lower than the thermal conductivity B (A < B), the thermal conductivity A is lower than the thermal conductivity D (A < D), the thermal conductivity C is lower than the thermal conductivity B (C < B), and the thermal conductivity C is lower than the thermal conductivity D (C < D) is satisfied, as the heat exchange efficiency requirement level LY increases, the thickness of the coating layer is required to increase.

[0070] For example, when the acquired value of the heat exchange efficiency requirement level LY obtained for each part of the heat transfer tube 21 (see Fig. 1A, etc.) is greater than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer is required to be greater than the recommended thickness TYs of the coating layer set when the heat exchange efficiency requirement level LY is the reference value.

[0071] The thickness TY of the coating layer is varied according to the difference value between the acquired value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY. That is, when the acquired value of the heat exchange efficiency requirement level LY is greater than the reference value of the heat exchange efficiency requirement level LY, as the difference value between the acquired value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases, the thickness TY of the coating layer is required to increase. On the other hand, when the acquired value of the heat exchange efficiency requirement level LY is smaller than the reference value of the heat exchange efficiency requirement level LY, as the difference value between the acquired value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases, the thickness TY of the coating layer is required to decrease.

[0072] [B-3-2-2-2] When at least one of the relationships A > B, A > D, C > B, and C > D is satisfied (Case 2-2) When thermal conductivity A is higher than thermal conductivity B (A>B), when thermal conductivity A is higher than thermal conductivity D (A>D), when thermal conductivity C is higher than thermal conductivity B (C>B), and when thermal conductivity C is higher than thermal conductivity D (C>D), the thickness of the coating layer is required to decrease as the required heat exchange efficiency level LY increases.

[0073] For example, if the obtained value of the heat exchange efficiency requirement level LY for each part of the heat transfer tube 21 (see Figure 1A, etc.) is greater than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer will be made thinner than the recommended thickness TYs set when the heat exchange efficiency requirement level LY is at the reference value.

[0074] The thickness TY of the coating layer is varied according to the difference between the obtained value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY. In other words, if the obtained value of the heat exchange efficiency requirement level LY is greater than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer is required to become thinner as the difference between the obtained value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases. On the other hand, if the obtained value of the heat exchange efficiency requirement level LY is smaller than the reference value of the heat exchange efficiency requirement level LY, the thickness TY of the coating layer is required to become thicker as the difference between the obtained value of the heat exchange efficiency requirement level LY and the reference value of the heat exchange efficiency requirement level LY increases.

[0075] [B-3-3] Calculation of the thickness TZ of the coating layer covering the outer surface S1 of the heat transfer tube 21 The thickness TZ of the coating layer covering the outer surface S1 of the heat transfer tube 21 (see Figure 1A, etc.) is determined based on both the thickness TX determined according to the corrosion risk level LX and the thickness TY determined according to the heat exchange efficiency requirement level LY.

[0076] For example, the average value of the thickness TX determined according to the corrosion risk level LX and the thickness TY determined according to the heat exchange efficiency requirement level LY is used as the thickness TZ of the coating layer covering the outer surface S1 of the heat transfer tube 21. The thickness TZ of the coating layer is determined for each part of the outer surface S1 of the heat transfer tube 21.

[0077] In addition to the above, the thickness TZ of the coating layer may also be determined, for example, by weighted averaging, from the thickness TX determined according to the corrosion risk level LX and the thickness TY determined according to the heat exchange efficiency requirement level LY.

[0078] [B-3-4] Execution of coating The coating layer is applied to a thickness TZ determined as described above. The coating layer is formed using a material that is less susceptible to corrosion than the heat transfer tube 21 by the corrosive components contained in the first medium F1. For example, the coating layer is applied by thermal spraying, where ceramic powder or the like is melted and sprayed onto the coating surface, and then solidified on the coating surface. The thickness TZ of the coating layer can be adjusted, for example, by changing the number of coats applied by thermal spraying. Note that the coating layer may also be applied by methods other than thermal spraying.

[0079] Figure 3 is a magnified view of a portion of the heat transfer tube 21 of a heat recovery boiler, which is a power generation-related device, in an embodiment. In Figure 3, the AA portion of Figure 1C is shown in a further magnified view.

[0080] As shown in Figure 3, a coating layer 30 is applied to the outer surface S1 (first surface) of the heat transfer tube 21. Here, the thickness TZ of the coating layer 30, determined according to the corrosion risk level LX and the heat exchange efficiency requirement level LY, is shown as being thicker on the upstream side than on the downstream side (right side) in the flow direction (x direction) of the first medium F1. Depending on the thickness TZ of the coating layer 30 determined according to the corrosion risk level LX and the heat exchange efficiency requirement level LY, the opposite may be true from the case shown in Figure 3. Also, in some cases, there may be parts that are not covered by the coating layer 30.

[0081] [C] Summary As described above, in this embodiment, the distribution of corrosion risk levels LX at which corrosion occurs on the outer surface S1 of the heat transfer tube 21 due to corrosive components contained in the first medium F1 is determined (ST10). Furthermore, the distribution of the required heat exchange efficiency level LY for the heat exchange efficiency between the first medium F1 and the second medium F2 in the heat transfer tube 21 is determined (ST20). When coating the outer surface S1 of the heat transfer tube 21 with a coating layer 30 (ST30), the thickness of the coating layer 30 is changed according to the corrosion risk level LX and the required heat exchange efficiency level LY.

[0082] Therefore, in this embodiment, a waste heat recovery boiler including a heat transfer tube 21 that can easily achieve both the suppression of corrosion and the high efficiency of heat exchange can be easily manufactured.

[0083] [D] Variation A modified example of the above embodiment will be described.

[0084] [D-1] Variation 1 Figure 4 is a magnified view of a portion of the heat transfer tube 21 of a heat recovery boiler, which is a power generation-related device, in Modification 1. In Figure 4, as in Figure 3, the AA portion of Figure 1C is shown in a further magnified view.

[0085] As shown in Figure 4, in this modified example, the coating layer 30 is formed such that the thickness of the coating layer 30 is greater in the corner portion where the heat transfer tube body 210 and the fins 212 are connected than in other portions. The first medium F1 tends to accumulate more easily in the corner portion where the heat transfer tube body 210 and the fins 212 are connected than in other portions, resulting in a higher corrosion risk level LX. For this reason, the thickness of the coating layer 30 is adjusted and the coating layer 30 is provided accordingly.

[0086] The coating layer 30 is formed in the form shown in Figure 4, for example, by surface tension acting on the molten material such as ceramic powder sprayed onto the coating surface by thermal spraying. Alternatively, the formation of the coating layer 30 may be carried out by controlling the melting of the molten material using the flow of the surrounding fluid or gravity, as shown in Figure 4. Naturally, the thickness can be adjusted by changing other coating conditions (for example, the number of coating steps, spray angle, spray flow rate, etc.).

[0087] [D-2] Variation 2 Figures 5A, 5B, and 5C illustrate the process of manufacturing a waste heat recovery boiler, which is a power generation-related device, in Modification 2. Figures 5A, 5B, and 5C schematically show the connection between multiple heat transfer tubes 21 and the header 221 (see Figure 1B).

[0088] In this modified example, when connecting multiple heat transfer tubes 21 to the header 221, as shown in Figure 5A, a coating layer 30 is first provided on each of the multiple heat transfer tubes 21 and the header 221. Here, the coating layer 30 is formed on the parts of the multiple heat transfer tubes 21 other than the side connected to the header 221. Similarly, the coating layer 30 is formed on the parts of the header 221 other than the parts to which the multiple heat transfer tubes 21 are connected. For example, the formation of the coating layer 30 is carried out as described above by masking the parts other than the surface on which the coating layer 30 is formed.

[0089] Next, as shown in Figure 5B, each of the multiple heat transfer tubes 21, on which the coating layer 30 is formed, is connected to the header section 221, on which the coating layer 30 is also formed. The connection between the two is performed, for example, by joining such as welding or by assembly with screws.

[0090] Subsequently, as shown in Figure 5C, a coating layer 30 is formed on the connecting portion where the multiple heat transfer tubes 21 and the header portion 221 are connected.

[0091] As described above, by forming the coating layer 30, the thickness of the coating layer 30 can be accurately adjusted according to the corrosion risk level LX and the heat exchange efficiency requirement level LY, thereby fully obtaining the effects of the above embodiment.

[0092] [D-3] Other variations

[0093] In the above embodiment, the case in which the power generation-related equipment is a waste heat recovery boiler was described, but it is not limited to this. The power generation-related equipment may also be other components of the power plant, such as a flue (including a chimney) through which gas (first medium F1) is discharged from the waste heat recovery boiler.

[0094] In the above embodiment, an example was given in which the thickness TZ of the coating layer covering the outer surface S1 of the heat transfer tube 21 is determined from the thickness TX determined based on the corrosion risk level LX and the thickness TY determined based on the heat exchange efficiency requirement level LY, but the embodiment is not limited to this. For example, the thickness TZ may be determined from the corrosion risk level LX and the heat exchange efficiency requirement level LY using a lookup table that associates the corrosion risk level LX, the heat exchange efficiency requirement level LY, and the thickness TZ.

[0095] <Other> While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0096] 20: Container, 21: Heat transfer tube (wall), 30: Coating layer, 210: Heat transfer tube body, 212: Fin, 221: Header, 222: Header, F1: First medium, F2: Second medium, S1: Outer surface (first surface), S2: Inner surface (second surface)

Claims

1. A method for manufacturing a power generation-related device, comprising a wall portion having a first surface through which a first medium containing corrosive components flows and corrosion occurs due to the corrosive components, and a second surface through which a second medium flows, wherein heat exchange between the first medium and the second medium is performed through the wall portion, A corrosion risk level acquisition step, which determines the distribution of corrosion risk levels at which corrosion occurs due to the corrosive components in the first surface, A heat exchange efficiency requirement level acquisition step, which determines the distribution of the required heat exchange efficiency levels for the heat exchange efficiency of the heat exchange in the wall portion, A coating step of coating the first surface with a coating layer and Having one or more of the following processes, In the coating step, the thickness of the coating layer is changed according to the corrosion risk level and / or the heat exchange efficiency requirement level, and the coating of the coating layer is performed. Manufacturing method for power generation-related equipment.

2. In the coating process, the thickness of the coating layer is increased as the corrosion risk level increases. A method for manufacturing power generation-related equipment as described in claim 1.

3. When there is no foreign matter layer consisting of at least one of an adhering material layer and a corrosive material layer on the first surface of the wall portion, The thermal conductivity A of the wall portion and the thermal conductivity B of the laminated structure formed by covering the first surface of the wall portion with the coating layer are, If the relationship A < B is satisfied, in the coating process, the thickness of the coating layer is increased as the required level of heat exchange efficiency increases. If the relationship A > B is satisfied, in the coating process, the thickness of the coating layer is reduced as the required level of heat exchange efficiency increases. A method for manufacturing power generation-related equipment as described in claim 1.

4. When a foreign matter layer consisting of at least one of an adhering material layer and a corrosive material layer is present on the first surface of the wall portion, The thermal conductivity A of the wall portion, the thermal conductivity B of the laminated structure formed by covering the first surface of the wall portion with the coating layer, the thermal conductivity C of the laminated structure formed by providing the foreign material layer on the first surface of the wall portion, and the thermal conductivity D of the laminated structure formed by providing the foreign material layer on the first surface of the wall portion and covering the first surface of the wall portion with the coating layer via the foreign material layer, If at least one of the following relationships is satisfied: A < B, A < D, C < B, and C < D, then in the coating process, the thickness of the coating layer is increased as the required level of heat exchange efficiency increases. If at least one of the following relationships is satisfied: A > B, A > D, C > B, and C > D, then in the coating process, the thickness of the coating layer is reduced as the required level of heat exchange efficiency increases. A method for manufacturing power generation-related equipment as described in claim 1.

5. The wall portion is formed of a metallic material containing at least one component of Fe, Al, Zn, Cu, Ni, and Cr. A method for manufacturing power generation-related equipment as described in claim 1.

6. The corrosive component is at least one of the following: hydrogen ions, hydroxide ions, hydrochloride ions, nitrate ions, sulfate ions, hydrogen sulfide ions, chloride ions, carbonate ions, ammonium ions, hydroxide salts, hydrochloride salts, nitrates, sulfates, chloride salts, carbonates, and ammonium salts. A method for manufacturing power generation-related equipment as described in claim 1.

7. The aforementioned power generation equipment is a waste heat recovery boiler. A method for manufacturing power generation-related equipment as described in claim 1.

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