JP7174814B1 - Sampling equipment and boiler plant - Google Patents

Abstract

A sampling device capable of suppressing deposition of scale on the surface of a heat transfer tube of a sample water cooler is provided. A sampling device for sampling feed water supplied to a boiler or steam generated in the boiler, comprising a sample water extraction line for extracting sample water from the feed water supplied to the boiler or steam generated in the boiler; a sample water cooler including a cooling water channel through which cooling water flows; a first heat transfer tube disposed in the cooling water channel and through which sample water extracted by the sample water extraction line flows; and a sample water cooler in the sample water extraction line. A cold medium flow path through which the cold medium flows, and a second heat transfer tube arranged in the cold medium flow path and through which the sample water extracted by the sample water extraction line flows. and a precooler including. [Selection drawing] Fig. 3

Description

The present disclosure relates to sampling apparatus and boiler plants.

Conventionally, for example, in a thermal power plant, etc., a sampling device is provided in order to determine whether various types of feed water, including steam including main steam and boiler water, have appropriate TDS (Total Dissolved Solids). There is Such a sampling device may have a sample water cooling cooler (sample water cooler) for cooling the sample water in order to safely sample the relatively hot sample water. For example, US Pat. No. 6,200,000 discloses a sample water cooler in a sampling device for a boiler plant.

JP-A-6-347383

For example, when the circulating water of the cooling tower of a boiler plant is used as the cooling water for the sample water cooler, each component of the cooling water is concentrated and deposited as scale, and the scale adheres to the surface of the heat transfer tube in the sample water cooler. There is When the amount of scale adhering to the surface of the heat transfer tube increases, the flow path of the cooling water in the sample water cooler narrows, forming a stagnant part of the cooling water flow, and the components that promote corrosion of the heat transfer tube are concentrated. Stress corrosion cracking may occur in heat transfer tubes. In addition, at locations where a large amount of scale adheres to the surface of the heat transfer tube, the amount of heat exchange decreases and heat spots are generated, which may cause holes in the heat transfer tube. As described above, if scale adhesion progresses on the surfaces of the heat transfer tubes in the sample water cooler, the heat transfer tubes may be damaged and the sample water may leak from the heat transfer tubes.

Regarding this point, Patent Literature 1 does not disclose the problem of scale deposition on the surface of the heat transfer tube of the sample water cooler and knowledge about its solution.

In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a sampling device and a boiler plant that can suppress the deposition of scale on the surfaces of the heat transfer tubes of the sample water cooler.

To achieve the above object, a sampling device according to at least one embodiment of the present disclosure comprises:
A sampling device for sampling feed water supplied to a boiler or steam generated in the boiler,
a sample water extraction line for extracting sample water from one of feed water supplied to the boiler and steam generated in the boiler;
a sample water cooler including: a cooling water channel through which cooling water flows; and a first heat transfer tube arranged in the cooling water channel and through which the sample water extracted by the sample water extraction line flows;
A pre-cooler provided on the upstream side of the sample water cooler in the sample water extraction line, and comprising: a cooling medium channel through which a cooling medium flows; a precooler comprising a second heat transfer tube through which the extracted sample water flows;
Prepare.

In order to achieve the above object, a boiler plant according to at least one embodiment of the present disclosure includes
A boiler and the sampling device are provided.

According to at least one embodiment of the present disclosure, there are provided a sampling device and a boiler plant capable of suppressing scale deposition on the surfaces of heat transfer tubes of a sample water cooler.

1 is a schematic diagram (boiler turbine system diagram) showing a water supply system and a steam system of a boiler plant 2 according to one embodiment; FIG. FIG. 2 is a schematic diagram showing a cooling water system of the boiler plant 2 shown in FIG. 1; 4 is a schematic diagram showing an example of the configuration of a sampling device 46; FIG. 4 is a schematic cross-sectional view showing an example of the configuration of a sample water cooler 50; FIG. 5 is a schematic cross-sectional view showing an example of the configuration of a precooler 52; FIG.

Several embodiments of the present disclosure 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 invention, but are merely illustrative examples. .
For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement 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.
For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense, but also include irregularities and chamfers to the extent that the same effect can be obtained. The shape including the part etc. shall also be represented.
On the other hand, the expressions "comprising", "comprising", "having", "including", or "having" one component are not exclusive expressions excluding the presence of other components.

FIG. 1 is a schematic diagram (boiler turbine system diagram) showing a water supply system and a steam system of a boiler plant 2 according to one embodiment.
A boiler plant 2 shown in FIG. 1 includes a boiler 3, a steam turbine 4, a water supply line 5 for supplying water (feed water) to the boiler 3, and a steam line 6 through which steam generated in the boiler 3 flows. In addition, the feed water line 5 includes a condenser 8, a condensate pump 10, a low pressure feed water heater 12, a deaerator 14, a boiler feed water pump 16, a high pressure feed water heater 18, and an economizer 20 in this order from the upstream side. is provided. Further, the steam line 6 is provided with a superheater 24 between the steam drum 22 of the boiler 3 and the high pressure stage 4a of the steam turbine 4, and between the high pressure stage 4a and the low pressure stage 4b of the steam turbine 4. A reheater 26 is provided. The boiler plant 2 may be a thermal power plant including a generator (not shown) driven by the steam turbine 4 .

The feed water (condensate) leaving the condenser 8 is pressurized by the condensate pump 10, heated by the low-pressure feed water heater 12, and then deaerator 14 to remove non-condensable gases (dissolved oxygen, etc.). be. The feedwater leaving the deaerator 14 is further pressurized by the boiler feedwater pump 16, heated by the high-pressure feedwater heater 18, and then heated by the economizer 20 using the combustion gas of the boiler 3 to produce the steam of the boiler 3. A drum 22 is supplied. The steam generated in the steam drum 22 of the boiler 3 is superheated by the superheater 24 to become superheated steam, which is supplied to the high pressure stage 4 a of the steam turbine 4 . The steam that has done work in the high pressure stage 4 a of the steam turbine 4 is supplied to the reheater 26 to be heated again and supplied to the low pressure stage 4 b of the steam turbine 4 . The steam that has worked in the low-pressure stage 4b of the steam turbine 4 is cooled and condensed in the condenser 8, and supplied to the boiler 3 again as feed water.

FIG. 2 is a schematic diagram showing the cooling water system of the boiler plant 2 shown in FIG.
As shown in FIG. 2, the boiler plant 2 includes a cooling tower 32 for cooling cooling water used in a plurality of devices 30 provided in the boiler plant 2, and cooling water cooled by the cooling tower 32 to the plurality of devices 30. A cooling water supply line 34 to be supplied, a cooling water recovery line 36 for recovering cooling water used in a plurality of devices 30 and returning it to the cooling tower 32, and a cooling water recovery line 36 branched from the cooling water recovery line 36 to discharge the cooling water as blow water. A blow water line 38 for blowing water, a make-up water line 40 for supplying make-up water (cooling water) to the cooling tower 32, and an overflow line 42 for discharging water overflowing from the cooling tower 32 are provided. A cooling water pump 44 is provided in the cooling water supply line 34 , and cooling water pressurized by the cooling water pump 44 is supplied to the plurality of devices 30 . The plurality of devices 30 includes a sampling device 46 for sampling the above-described feed water supplied to the boiler 3 or the steam generated in the boiler 3 as sample water.

FIG. 3 is a schematic diagram showing an example of the configuration of the sampling device 46. As shown in FIG. The sampling device 46 may be provided, for example, at each of the sampling points S1 to S7 in FIG. 1, or may be provided at any one or more of the sampling points S1 to S7.

Note that in the example shown in FIG. 1 , the sampling point S1 is a position in the steam line 6 between the superheater 24 and the high pressure stage 4 a of the steam turbine 4 . Sampling point S2 is a position in steam line 6 between reheater 26 and low pressure stage 4b of steam turbine 4 . Sampling point S3 is a position in steam line 6 between steam drum 22 and superheater 24 . Sampling point S4 is steam drum 22 . A sampling point S5 is a position between the high pressure feed water heater 18 and the economizer 20 in the feed water line 5 . A sampling point S6 is a position in the feedwater line 5 between the deaerator 14 and the boiler feedwater pump 16 . A sampling point S7 is a position between the low-pressure feed water heater 12 and the deaerator 14 in the feed water line 5 .

As shown in FIG. 3, the sampling system 46 includes a sample water extraction line 48, a sample water cooler 50, a precooler 52, and a water quality monitoring instrument 53. As shown in FIG.

The sample water extraction line 48 is configured to extract sample water from any of the sampling points S1-S7, for example. That is, the sample water extraction line 48 is configured to extract sample water from feed water supplied to the boiler 3 or steam generated in the boiler 3 . The sample water extraction line 48 extracts the steam generated in the boiler 3 from the steam line 6 as the sample water when sample water is extracted from any one of the sampling points S1 to S3, for example. The sample water extraction line 48 extracts the water supply supplied to the boiler 3 from the water supply line 5 or the steam drum 22 as sample water, for example, when sample water is extracted from any one of the sampling points S4 to S7.

The sample water cooler 50 includes a cooling water channel 54 through which cooling water flows, and a first heat transfer tube 56 arranged in the cooling water channel 54 and through which the sample water extracted by the sample water extraction line 48 flows. In the illustrated configuration, the first heat transfer tube 56 includes a helical (coiled) heat transfer tube portion 56a. In the sample water cooler 50, the first heat transfer tube 56 is immersed in the cooling water flowing through the cooling water flow path 54, and the sample water flowing through the first heat transfer tube 56 and the cooling water flowing through the cooling water flow path 54 are the first The sample water is cooled by the cooling water by exchanging heat through the heat transfer tube 56 . The sample water cooler 50 is an immersion heat exchanger and includes a vessel 66 with a cooling water inlet 62 and a cooling water outlet 64 formed therein. Inside the container 66 , the cooling water flow path 54 is formed so as to connect the inlet 62 and the outlet 64 .

Cooling water used in the sample water cooler 50 is supplied to the sample water cooler 50 through the cooling water supply line 34 from the cooling tower 32 described using FIG. This cooling water contains calcium carbonate and magnesium silicate.

The precooler 52 is provided upstream of the sample water cooler 50 in the sample water extraction line 48 . The precooler 52 includes a cooling water flow path 58 (cooling medium flow path) through which cooling water (cooling medium) flows, and a second flow path arranged in the cooling water flow path 58 through which the sample water extracted by the sample water extraction line 48 flows. a heat tube 60; In the illustrated configuration, the second heat transfer tube 60 includes a U-shaped heat transfer tube portion 60a, and the entire second heat transfer tube 60 is configured in a U shape. In the precooler 52, the second heat transfer tubes 60 are immersed in the cooling water flowing through the cooling water flow paths 58, and the sample water flowing through the second heat transfer tubes 60 and the cooling water flowing through the cooling water flow paths 58 are in a second heat transfer state. The sample water is cooled by the cooling water by exchanging heat through the heat tube 60 . The precooler 52 is an immersion heat exchanger and includes a vessel 74 having a cooling water inlet 70 and a cooling water outlet 72 formed therein. The cooling water flow path 58 is formed inside the container 74 so as to connect the inlet 70 and the outlet 72 . The temperature of the sample water at the inlet 70 of the precooler 52 in the sample water extraction line 48 may be, for example, 300° C. or higher.

Here, Vss is the volume of the first heat transfer tube 56 in the sample water cooler 50, Vsc is the volume of the cooling water flow path 54 in the sample water cooler 50, Vps is the volume of the second heat transfer tube 60 in the precooler 52, and Vps is the volume of the second heat transfer tube 60 in the precooler 52. Assuming that the volume of the cooling water flow path 58 is Vpc, the sample water cooler 50 and the precooler 52 are configured to satisfy Vps/Vpc<Vss/Vsc. That is, the ratio Vps/Vpc of the volume of the second heat transfer tube 60 to the volume of the cooling water flow path 58 in the precooler 52 is the ratio of the volume of the first heat transfer tube 56 to the volume of the cooling water flow path 54 in the sample water cooler 50. Vss/Vsc is smaller than Vss/Vsc.

The volume Vss of the first heat transfer tube 56 in the sample water cooler 50 is the sum of the volume of the thick portion of the first heat transfer tube 56 in the sample water cooler 50 and the volume of the internal space of the first heat transfer tube 56. means. In addition, the volume Vsc of the cooling water flow path 54 in the sample water cooler 50 is the space through which the cooling water in the sample water cooler 50 passes (the outside of the first heat transfer tube 56 in the cooling water flow path 54 that is the internal space of the container 66 space). Further, the volume Vps of the second heat transfer tubes 60 in the precooler 52 means the sum of the volume of the thick portion of the second heat transfer tubes 60 in the precooler 52 and the volume of the internal space of the second heat transfer tubes 60. . The volume Vpc of the cooling water flow path 58 in the precooler 52 is the space through which the cooling water in the precooler 52 passes (the space outside the second heat transfer tube 60 in the cooling water flow path 58 that is the internal space of the container 74. ) means the volume of

The water quality monitoring instrument 53 is provided on the downstream side of the sample water cooler 50 in the sample water extraction line 48, and measures the quality of the sample water that passes through the precooler 52 and the sample water cooler 50 in order and is cooled. It is configured. The water quality monitoring instrument 53 may be, for example, a pH meter that measures the pH of the sample water, a TDS meter that measures the TDS of the sample water, other measuring instruments, or a combination thereof.

According to the sampling device 46, the sample water is cooled by the precooler 52 provided upstream of the sample water cooler 50 in the sample water extraction line 48, thereby lowering the temperature of the sample water at the inlet 88 of the sample water cooler 50. can be made Since the cooling water contains components (such as calcium carbonate and magnesium silicate) that become more soluble in water as the temperature decreases, a precooler 52 is provided to cool the sample water at the inlet 88 of the sample water cooler 50 . By lowering the temperature of the sample water cooler 50, deposition of scale on the surface of the first heat transfer tube 56 of the sample water cooler 50 can be suppressed. As a result, it is possible to reduce the adhesion rate of scale on the surface of the first heat transfer tube 56 and suppress an increase in the amount of adhesion of scale. Therefore, breakage of the first heat transfer tube 56 due to scale can be suppressed, and leakage of the sample water from the first heat transfer tube 56 can be suppressed. Moreover, the load of the cleaning work which removes a scale can be reduced.

In addition, in the sampling device 46, the ratio Vps/Vpc of the volume of the second heat transfer tube 60 to the volume of the cooling water flow path 58 in the precooler 52 is the first transmission volume to the volume of the cooling water flow path 54 in the sample water cooler 50. Since the volume ratio Vss/Vsc of the heat pipe 56 is smaller than the cooling water flow path 58 of the precooler 52 , the cooling water is less likely to stagnate than the cooling water flow path 54 of the sample water cooler 50 . Therefore, it is possible to suppress the formation of a local high-temperature portion on the surface of the second heat transfer tube 60, and the sample water can be cooled relatively uniformly. Scale deposition can be suppressed.

Thus, the precooler 52 on the upstream side under which the temperature of the sample water in the sample water extraction line 48 is a high temperature condition that facilitates scale deposition has a structure in which scale is less likely to deposit than the sample water cooler 50 (Vps/Vpc< A structure that satisfies Vss/Vsc) is adopted, and the sample water cooler 50 on the downstream side into which the sample water whose temperature has been lowered to some extent by the precooler 52 flows has a structure that facilitates obtaining a large amount of heat exchange (Vps/Vpc < Vss/ By adopting the structure that satisfies Vsc), not only the deposition of scale on the surface of the first heat transfer tube 56 of the sample water cooler 50 but also the deposition of scale on the surface of the second heat transfer tube 60 of the precooler 52 is suppressed. The sample water cooler 50 and precooler 52 significantly reduce the temperature of the sample water so that the sample water can be safely sampled.

In addition, in the example shown in FIG. 3, the second heat transfer tube 60 of the precooler 52 is configured by the heat transfer tube portion 60a having a simple U-shaped structure. As compared with the sample water cooler 50 having the precooler 52, the cooling water is less likely to flow unevenly (uneven flow) in the cooling water flow path 58 of the precooler 52. Therefore, the cooling water can flow relatively uniformly over the entire surface of the second heat transfer tube 60 of the precooler 52, and localized high-pitched sounds are less likely to be formed on the surface of the second heat transfer tube 60 as described above. , the deposition of scale on the surface of the second heat transfer tube 60 can be effectively suppressed. In addition, since the precooler 52 has a simple structure with little occurrence of drift, cleaning is easy, and the load of cleaning work can be reduced.

Further, according to the findings of the inventors of the present application, when the cooling water contains at least one of calcium carbonate and magnesium silicate, when the temperature of the sample water at the inlet of the sample water cooler exceeds 300° C., the first heat transfer tube 56 As the deposition rate of scale on the surface increases, the amount of scale adhered to the surface of the first heat transfer tube 56 tends to increase significantly.

In this respect, in the sampling device 46, the temperature of the sample water at the inlet 70 of the precooler 52 in the sample water extraction line 48 is 300° C. or higher, and the provision of the precooler 52 reduces the temperature of the sample water at the outlet 72 of the precooler 52. (ie, the temperature of the sample water at the inlet 62 of the sample water cooler 50) is reduced to 300°C or less. As a result, it is possible to effectively suppress deposition of scale on the surfaces of the first heat transfer tubes 56 due to calcium carbonate and magnesium silicate contained in the cooling water.

The present disclosure 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.

For example, as the sample water cooler 50 applied to the sampling device 46 shown in FIG. 3, an immersion double wound type sample water cooler 50 as shown in FIG. 4 may be used. In each configuration of the sample water cooler 50 shown in FIG. 4, those having the same functions as those of the configuration of the sample water cooler 50 described with reference to FIG.

The first heat transfer tube 56 of the sample water cooler 50 shown in FIG. It has a double-wound helical structure including a helical outer heat transfer tube portion 56o having a second helical radius larger than the first helical radius.

In the example shown in FIG. 4, the sample water cooler 50 includes a cooling water introduction pipe 80 inserted through one end side in the longitudinal direction of the container 66, and a cooling water introduction pipe 80 provided coaxially with the cooling water introduction pipe 80 on the outer peripheral side of the cooling water introduction pipe 80. The cooling water flow path 54 is defined by the container 66 , the cooling water introduction pipe 80 and the inner cylinder wall 82 . The axial direction of the cooling water introduction pipe 80 and the axial direction of the inner cylinder wall 82 match the longitudinal direction of the container 66 . The inner peripheral heat transfer tube portion 56 i is arranged between the outer peripheral surface of the cooling water introduction pipe 80 and the inner peripheral surface of the inner cylinder wall 82 , and the outer peripheral heat transfer tube portion 56 o is located between the outer peripheral surface of the inner cylinder wall 82 and the container 66 . placed between the inner surface.

A gap 84 is provided between the inner surface of the container 66 and the tip of the cooling water introduction pipe 80 , and the cooling water flowing through the cooling water introduction pipe 80 along the longitudinal direction of the container 66 flows in the gap 84 . , and flows along the longitudinal direction of the container 66 between the cooling water introduction pipe 80 and the inner cylinder wall 82 .
The inner cylinder wall 82 extends from the other longitudinal end of the container 66 toward the one end, and a gap 86 is provided between the inner surface of the container 66 and the tip of the inner cylinder wall 82 . The cooling water flowing along the longitudinal direction of the container 66 between the cooling water introduction pipe 80 and the inner cylinder wall 82 reverses the flow direction at the gap 86, and the outer peripheral surface of the inner cylinder wall 82 and the inner surface of the container 66 After flowing along the longitudinal direction of the container 66 , it is discharged from the outlet 64 provided on the other end side of the container 66 in the longitudinal direction.

In the example shown in FIG. 4, the sample water inlet 88 and the sample water outlet 90 in the sample water cooler 50 are provided at the other longitudinal end of the container 66 . The sample water extracted by the sample water extraction line 48 passes through the inlet 88 of the sample water cooler 50, flows into one end of the outer heat transfer tube portion 56o, and flows to the other end of the outer heat transfer tube portion 56o. The other end of the outer heat transfer tube portion 56o and one end of the inner heat transfer tube portion 56i are connected, and the sample water flowing to the other end of the outer heat transfer tube portion 56o is It flows from one end to the other end of the inner peripheral heat transfer tube portion 56 i and is discharged from the outlet 90 of the sample water cooler 50 .

In some embodiments, instead of the precooler 52 in the sampling device 46 shown in FIG. 3, a precooler 52 with a second heat transfer tube 60 as illustrated in FIG. 5 may be used. In each structure of the precooler 52 shown in FIG. 5, the same reference numerals are assigned to the components having the same functions as those of the precooler 52 described with reference to FIG. 3, and common description thereof is omitted.

In the precooler 52 illustrated in FIG. 5, the second heat transfer tube 60 includes an inlet side header 92, an outlet side header 94, and a plurality of heat transfer tube portions 60s connecting the inlet side header 92 and the outlet side header 94. include. Each of the multiple heat transfer tube portions 60 s extends linearly along the longitudinal direction of the container 74 .

In the illustrated example, the sample water inlet 76 (the inlet of the second heat transfer tube 60) in the sample water cooler 50 is formed at one end side in the longitudinal direction of the container 74, and the sample water outlet 78 (the second inlet) in the sample water cooler 50 is formed. The outlet of the heat transfer tube 60) is formed on the other end side of the container 74 in the longitudinal direction. An inlet 70 of the cooling water channel 58 is formed on the other end side of the container 74 in the longitudinal direction, and an outlet 72 of the cooling water channel 58 is formed on the one end side of the container 74 in the longitudinal direction.

The specific configurations of the sample water cooler and precooler are not limited to the above examples. Regardless of the specific configurations of the sample water cooler and the pre-cooler, the ratio Vps/Vpc of the volume of the second heat transfer tube to the volume of the cooling water channel in the precooler is set to the first volume of the cooling water channel in the sample water cooler. By making the volume ratio of the heat transfer tubes smaller than Vss/Vsc, deposition of scale on the surface of the first heat transfer tubes 56 is suppressed, and sample water having a temperature higher than that of the first heat transfer tubes 56 flows through the second heat transfer tubes 60. The deposition of scale on the surface of the can also be suppressed.

In some of the embodiments described above, the precooler 52 includes a cooling water flow path 58 through which cooling water flows, and a second cooling water flow path 58 arranged in the cooling water flow path 58 through which the sample water extracted by the sample water extraction line 48 flows. A heat transfer tube 60 was provided. However, the precooler may be configured to cool the sample water using a cooling medium other than cooling water (for example, cooling air). That is, the precooler may include a cooling medium flow path through which the cooling medium flows, and a second heat transfer tube disposed in the cooling medium flow path and through which the sample water extracted by the sample water extraction line flows.

In addition, the cooling water used in the sample water cooler may contain both calcium carbonate and magnesium silicate, which are poorly soluble substances that cause scale, or may contain only one of calcium carbonate and magnesium silicate. You may That is, at least one of calcium carbonate and magnesium silicate may be contained. In addition, the above sampling device can be suitably used when the cooling water contains not only calcium carbonate and magnesium silicate but also poorly soluble substances whose solubility in water decreases as the water temperature rises.

The contents described in each of the above embodiments are understood as follows, for example.

(1) A sampling device according to at least one embodiment of the present disclosure (eg, the sampling device 46 described above)
A sampling device for sampling feedwater supplied to a boiler (for example, the boiler 3 described above) or steam generated in the boiler,
a sample water extraction line (e.g., sample water extraction line 48 described above) configured to extract sample water from feedwater supplied to the boiler or steam generated by the boiler;
a sample water cooler including: a cooling water channel through which cooling water flows; and a first heat transfer tube arranged in the cooling water channel and through which the sample water extracted by the sample water extraction line flows;
A pre-cooler provided on the upstream side of the sample water cooler in the sample water extraction line, and comprising: a cooling medium channel through which a cooling medium flows; a precooler comprising a second heat transfer tube through which the extracted sample water flows;
Prepare.

According to the sampling apparatus described in (1) above, the sample water is cooled by the precooler provided upstream of the sample water cooler in the sample water extraction line, thereby lowering the temperature of the sample water at the inlet of the sample water cooler. can be made Cooling water contains components (e.g., calcium carbonate, magnesium silicate, etc.) whose solubility in water increases as the temperature decreases, so a precooler is provided to lower the temperature of the sample water at the inlet of the sample water cooler. As a result, deposition of scale on the surface of the first heat transfer tube of the sample water cooler can be suppressed. As a result, it is possible to reduce the adhesion rate of scale on the surface of the first heat transfer tube, thereby suppressing an increase in the amount of adhesion of scale. Therefore, damage to the first heat transfer tube due to scale can be suppressed, and leakage of sample water from the first heat transfer tube can be suppressed.

(2) In some embodiments, in the sampling device described in (1) above,
Vss is the volume of the first heat transfer tube in the sample water cooler, Vsc is the volume of the cooling water flow path in the sample water cooler, Vps is the volume of the second heat transfer tube in the precooler, and Vps is the cold medium in the precooler. The sample water cooler and the precooler are configured to satisfy Vps/Vpc<Vss/Vsc, where Vpc is the volume of the channel.

In the sampling device described in (2) above, the ratio Vps/Vpc of the volume of the second heat transfer tube to the volume of the cooling medium flow path in the precooler is the first heat transfer tube to the volume of the cooling water flow path in the sample water cooler. is smaller than the volume ratio Vss/Vsc of the precooler, which makes it more difficult for cooling water to stagnate in the cooling medium flow path of the precooler than in the cooling water flow path of the sample water cooler. For this reason, it is possible to suppress the formation of local high-temperature areas on the surface of the second heat transfer tube, and the sample water can be cooled relatively uniformly. Precipitation can be suppressed.
In this way, the upstream precooler, where the temperature of the sample water in the sample water extraction line is a high temperature condition that facilitates scale deposition, has a structure in which scale is less likely to deposit than the sample water cooler (Vps/Vpc<Vss/Vsc A structure that satisfies Vps/Vpc < Vss/Vsc) is adopted, and the sample water cooler on the downstream side, into which the sample water whose temperature has been lowered to some extent by the pre-cooler, flows in, is a structure that facilitates obtaining a large amount of heat exchange (structure that satisfies Vps/Vpc < Vss/Vsc). By adopting this, not only the deposition of scale on the surface of the heat transfer tube of the sample water cooler, but also the deposition of scale on the surface of the precooler is suppressed, while the temperature of the sample water is significantly lowered by the sample water cooler and the precooler. be able to.

(3) In some embodiments, in the sampling device according to (1) or (2) above,
The cold medium is the cooling water.

According to the sampling device described in (3) above, the cooling medium used in the precooler and the cooling water used in the sample water cooler can be shared.

(4) In some embodiments, in the sampling device according to any one of (1) to (3) above,
The cooling water contains at least one of calcium carbonate and magnesium silicate.

Calcium carbonate and magnesium silicate tend to become more soluble in water as the water temperature decreases. Therefore, according to the sampling apparatus described in (4) above, by lowering the temperature at the inlet of the sample water cooler by the precooler, scale caused by at least one of calcium carbonate and magnesium silicate is removed from the sample water cooler. Precipitation on the surface of the first heat transfer tube can be suppressed.

(5) In some embodiments, in the sampling device according to (4) above,
The temperature at the inlet of the precooler in the sample water extraction line is 300 degrees or higher.

When the cooling water contains at least one of calcium carbonate and magnesium silicate, when the temperature of the sample water at the inlet of the sample water cooler exceeds 300° C., the deposition rate of scale on the surface of the first heat transfer tube increases and the second 1. The amount of scale adhering to the surface of the heat transfer tube tends to increase significantly.
For this reason, as described in (5) above, by cooling the sample water at 300 ° C. or higher with a precooler before putting it into the sample water cooler, the deposition of scale on the surface of the first heat transfer tube of the sample water cooler is effectively prevented. can be effectively suppressed.

(6) In some embodiments, in the sampling device according to any one of (1) to (5) above,
The first heat transfer tube of the sample water cooler includes a spiral heat transfer tube section (such as the heat transfer tube sections 56a, 56i, 56o described above), and the second heat transfer tube of the precooler is U-shaped or straight. shaped heat transfer tube portions (for example, the heat transfer tube portions 60a and 60s described above).

According to the sampling device described in (6) above, the upstream precooler under which the temperature of the sample water in the sample water extraction line is a high temperature condition that facilitates scale deposition is provided with a simple precooler that is less susceptible to scale deposition than the sample water cooler. A structure (including a U-shaped or linear heat transfer tube part) is adopted, and a large amount of heat exchange is obtained in the downstream sample water cooler where the sample water whose temperature has been lowered to some extent by the pre-cooler flows. By adopting an easy structure (structure including a spiral heat transfer tube), not only the deposition of scale on the surface of the heat transfer tube of the sample water cooler but also the deposition of scale on the surface of the precooler is suppressed, and the sample water cooler The temperature of the sample water is greatly lowered by the precooler and the sample water can be safely sampled.

(7) A boiler plant according to at least one embodiment of the present disclosure (for example, the boiler plant 2 described above)
A boiler (for example, boiler 3 described above) and the sampling device described in any one of (1) to (6) above (for example, sampling device 46 described above) are provided.

According to the boiler plant described in (7) above, since the sampling device described in any one of (1) to (6) is provided, deposition of scale on the surface of the first heat transfer tube of the sample water cooler is suppressed. be able to. As a result, damage to the first heat transfer tube due to scale can be suppressed, and leakage of sample water from the first heat transfer tube can be suppressed.

2 boiler plant 3 boiler 4 steam turbine 4a high pressure stage 4b low pressure stage 5 feed water line 6 steam line 8 condenser 10 condensate pump 12 low pressure feed water heater 14 deaerator 16 boiler feed water pump 18 high pressure feed water heater 20 economizer 22 steam drum 24 superheater 26 reheater 30 equipment 32 cooling tower 34 cooling water supply line 36 cooling water recovery line 38 blow water line 40 makeup water line 42 overflow line 44 cooling water pump 46 sampling device 48 sample water extraction line 50 sample Water cooler 52 Pre-cooler 53 Water quality monitoring instruments 54, 58 Cooling water channel 56 First heat transfer tube 56 Heat transfer tube portion 56i Inner heat transfer tube portion 56o Outer heat transfer tube portion 60 Second heat transfer tube 60a Heat transfer tube portions 62, 70, 76, 88 Inlets 64, 72, 78, 90 Outlets 66, 74 Container 80 Cooling water introduction pipe 82 Inner cylinder walls 84, 86 Gap 92 Inlet side header 94 Outlet side header

Claims (6)

A sampling device for sampling feed water supplied to a boiler or steam generated in the boiler,
a sample water extraction line configured to extract sample water from feed water supplied to the boiler or steam generated by the boiler;
a sample water cooler including: a cooling water channel through which cooling water flows; and a first heat transfer tube arranged in the cooling water channel and through which the sample water extracted by the sample water extraction line flows;
A pre-cooler provided on the upstream side of the sample water cooler in the sample water extraction line, and comprising: a cooling medium channel through which a cooling medium flows; a precooler comprising a second heat transfer tube through which the extracted sample water flows;
with
Vss is the volume of the first heat transfer tube in the sample water cooler, Vsc is the volume of the cooling water flow path in the sample water cooler, Vps is the volume of the second heat transfer tube in the precooler, and Vps is the cold medium in the precooler. Where Vpc is the volume of the flow path, the sample water cooler and the precooler are configured to satisfy Vps/Vpc<Vss/Vsc.
sampling device. The sampling device according to claim 1 , wherein the cold medium is the cooling water. The sampling device according to claim 1 or 2 , wherein the cooling water contains at least one of calcium carbonate and magnesium silicate. 4. The sampling device according to claim 3 , wherein the temperature at the inlet of the precooler in the sample water extraction line is 300 degrees or higher. 5. The first heat transfer tube of the sample water cooler comprises a spiral heat transfer tube section, and the second heat transfer tube of the precooler comprises a U - shaped or straight heat transfer tube section. The sampling device according to any one of 1. A boiler plant comprising a boiler and the sampling device according to any one of claims 1 to 5 .

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