JP2021076315A - Multi-tube condenser - Google Patents

Abstract

To provide a multi-tube condenser capable of securing condensation performance.SOLUTION: A multi-tube condenser 100 that condenses turbine exhaust steam discharged from a steam turbine with a cooling medium, comprises: a condenser body 110 that accepts the turbine exhaust steam; a tube bundle 123 having a plurality of cooling tubes arranged in parallel with each other in the condenser body 110 to serve as a flow path for the cooling medium; an air cooling unit 140 that collects non-condensed gas discharged in a tube bundle area where the tube bundle 123 is arranged; and an extraction pipe 142 that serves as a flow path for air from the air cooling unit 140. The plurality of air cooling units 140 is provided in one tube bundle area.SELECTED DRAWING: Figure 4

Description

Embodiments of the present invention relate to a multi-tube condenser.

Condensers in steam turbine power plants such as thermal power and nuclear power keep the back pressure of the turbine in a vacuum by cooling and condensing the steam after rotating the steam turbine, and supply the condensed water to the boiler etc. again. Has a role. Generally, a surface-cooled multi-tube condenser is used for these condensers. The multi-tube condenser is from the main body to which the exhaust steam from the steam turbine flows in, the large number of cooling pipes housed in the main body, and the water chamber connected to the main body to supply cooling water to the cooling pipes. Mainly composed.

In order for the multi-tube condenser to exert its condensing capacity, it is important that steam gradually condenses on the outer surface of the cooling pipe housed in the main body and flows to the air cooling part of the tube bundle without staying smoothly. is there. The downstream side of the air cooling unit is connected to a non-condensable gas discharge device such as a vacuum pump, and the air cooling unit has a role of collecting and discharging the inflowing air due to an in-leak from the outside.

If the steam flow deteriorates in a part other than the air cooling part of the pipe bundle, air or the like stays in that part. Since a non-condensable gas such as air inhibits the condensation of vapor, the amount of vapor condensation decreases in the portion where the non-condensable gas stays. As a result, the performance of the condenser deteriorates. For this reason, it is important to arrange the cooling pipes in an arrangement that makes it difficult for the flow to stay in the condenser tube bundle, and to arrange the air cooling unit at the optimum position.

JP-A-2017-187220

There are various types of turbines in power plants that are connected to the condenser, such as a downward exhaust type that discharges steam vertically downward and an axial flow / side exhaust type that discharges steam in the horizontal direction. The flow conditions such as the steam flow velocity distribution and direction at the turbine exhaust outlet (condenser duct inlet) differ depending on the type. Even in the same turbine, the flow state changes due to changes in operating conditions due to changes in seawater temperature depending on the season, and aging deterioration such as scale adhesion.

Basically, it is not possible to change the arrangement of the condenser cooling pipes. Therefore, if the turbine exhaust conditions change significantly, the steam flow may stay in the bundle of pipes, and the original condensing performance of the condenser may not be exhibited.

Therefore, an embodiment of the present invention aims to provide a multi-tube condenser capable of ensuring condensing performance.

In order to achieve the above object, the multi-tube condenser according to the present embodiment is a multi-tube condenser that condenses the turbine exhaust steam discharged from the steam turbine with a cooling medium, and the turbine exhaust steam. It is located in the condenser main body that receives the gas, the pipe bundle having a plurality of cooling pipes arranged in the condenser main body and serving as a flow path of the cooling medium and arranged in parallel with each other, and the pipe bundle region in which the pipe bundle is arranged. The air cooling unit is provided with an air cooling unit for accumulating the discharged non-condensed gas and an extraction pipe serving as a flow path for the non-condensed gas from the air cooling unit. It is characterized in that it is provided.

It is a vertical sectional view which shows the structure of the multi-tube type condenser which concerns on 1st Embodiment. It is a cross-sectional view taken along the line II-II of FIG. 1 showing the configuration of the multi-tube condenser according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 4 showing the internal configuration of the multi-tube condenser according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line IV-IV of FIG. 3 showing the internal configuration of the multi-tube condenser according to the first embodiment. It is sectional drawing which shows the internal structure of the multi-tube type condenser which concerns on 2nd Embodiment. It is sectional drawing which shows the internal structure of the multi-tube type condenser which concerns on 3rd Embodiment. It is sectional drawing which shows the structure of the multi-tube type condenser in the case of the side exhaust system which concerns on 4th Embodiment. It is sectional drawing which shows the internal structure of the multi-tube type condenser in the case of the side exhaust system which concerns on 4th Embodiment.

Hereinafter, the multi-tube condenser according to the embodiment of the present invention will be described with reference to the drawings. Here, the parts that are the same as or similar to each other are designated by a common reference numeral, and the description of superimposition will be omitted.

[First Embodiment]
FIG. 1 is a vertical cross-sectional view showing the configuration of the multi-tube condenser according to the first embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 and 2 show a multi-tube condenser 100 in the case of a downward exhaust system.

In the multi-tube condenser 100, the turbine exhaust steam discharged from the steam turbine 1 is condensed by a cooling medium such as seawater, and the back pressure of the steam turbine is set to a high vacuum, that is, about 0.05 atm. Maintain a low pressure close to vacuum. Here, in the steam turbine 1, the rotating portion 2 is housed in the outer casing 3, and the lower part on the exhaust side communicates with the multi-tube condenser 100.

The multi-tube condenser 100 has a condenser main body 110, a condenser duct 105 for guiding turbine exhaust steam to the condenser main body 110, and a cooling structure 120.

The condenser duct 105 extends from the upper end to the lower end in a direction along the turbine axis and in a direction perpendicular to the turbine axis.

The condenser main body 110 has a box-shaped structure in which the upper end is opened and connected to the condenser duct 105, and the two side cylinders 112 extending along the turbine shaft and facing each other, and the direction of the turbine shaft It has an end plate 113 and a bottom plate 114 provided along the vertical direction.

The condenser main body 110 is a container for maintaining a high vacuum inside, and is also a container for recovering condensed condensate by cooling turbine exhaust steam. The condensate is temporarily stored in the condenser hot well formed by the bottom plate 114, the side body 112 around it, and the lower part of the end plate 113, and passes through the condensate outlet 130 attached to the underside of the bottom plate 114. Then, it is collected in a condensate system (not shown) by the condensate pipe 8.

The end plate 113 has an inlet side end plate 113a and an outlet side end plate 113b.

The cooling structure 120 has an inlet side water chamber 121, an outlet side water chamber 122, and a plurality of cooling pipes 123.

The inlet side water chamber 121 has a container-like structure attached to the outside of the inlet side end plate 113a, and the cooling water inlet nozzle 121a provided on the lower surface is connected to the circulating water inlet pipe 5 for supplying the cooling medium. Has been done. Similarly, the outlet side water chamber 122 has a container-like structure attached to the outside of the outlet side end plate 113b, and the cooling water outlet nozzle 122a provided on the lower surface is a circulating water outlet pipe for discharging the cooling medium. It is connected to 6.

The inlet side end plate 113a and the outlet side end plate 113b are pipe plates that communicate with the cooling pipe 123 and have through holes for supporting the cooling pipe 123, respectively. Instead of such a form, a tube plate portion may be prepared separately, and openings for attaching the tube plate portion may be formed in the inlet side end plate 113a and the outlet side end plate 113b. ..

Each of the plurality of cooling pipes 123 is arranged in a direction parallel to the rotating shaft 2a of the rotating portion 2 of the steam turbine 1, and penetrates the pipe plate of the inlet side end plate 113a and the pipe plate of the outlet side end plate 113b, respectively. Then, both ends are fixed by the pipe plate of the inlet side end plate 113a and the pipe plate of the outlet side end plate 113b. Further, each of the plurality of cooling pipes 123 is arranged in parallel with each other and is slidably supported in the axial direction by a pipe bundle support plate 126 provided at intervals in the turbine axial direction.

The plurality of cooling pipes 123 form a group of pipe bundles 124. As shown in FIG. 2, the area occupied by the tube bundle 124 is hereinafter referred to as a tube bundle area 125.

The cooling tubes 123 in the tube bundle region 125 are arranged at predetermined intervals from each other, but the intervals are relatively widened to form a plurality of flow paths (not shown) that guide the flow.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 4 showing the internal configuration of the multi-tube condenser according to the first embodiment, and FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. It is a sectional view. In addition, in FIG. 4, the illustration of the cooling pipe 123 surrounded by the surrounding plate 141 is omitted in order to avoid the drawing from being confused. Further, in FIG. 3, a part of the cooling pipe 123 arranged in the entire area in the pipe bundle region 125 is shown.

Since the rotating portion 2 of the steam turbine 1 shown in the upper part in FIGS. 1 and 2 is usually two low-pressure turbines having the same steam flow rate, the flow of turbine exhaust gas from above. Is symmetrical when viewed from the direction of FIG. Therefore, the cross-sectional shape of the pipe bundle region 125 that receives and cools the turbine exhaust steam is also formed to be symmetrical.

The multi-tube condenser 100 includes an air extraction unit 140. That is, since the pressure inside the condenser main body 110 is close to vacuum, it is inevitable that a small amount of air leaks in from the outside. In order to prevent such non-condensable gas such as air from accumulating in the condenser main body 110 and lowering the thermal efficiency of the turbine 1, the non-condensable gas is stored in the condenser main body by the air extraction unit 140. From 110, it leads to an air extractor or the like (not shown).

The air extraction unit 140 has a surrounding plate 141 and an extraction pipe 142.

The surrounding plate 141 is horizontally provided and arranged along the cooling pipe 123, and has a plurality of elements divided in the longitudinal direction. Each element is sequentially arranged between the inlet side end plate 113a, the plurality of pipe bundle support plates 126, and the outlet side end plate 113b from the inlet side of the cooling water, and both ends are fixed. Each element of the enclosing plate 141 consists of a central plate 141b extending longitudinally along the horizontal plane and two opposing plates 141a extending along the central plate 141b and connected to both sides of the central plate 141b in the width direction. Have. The cross-sectional shape of the surrounding plate 141 is U-shaped and is open downward.

The extraction pipe 142 has an air cooling unit outlet pipe 142a connected to each surrounding plate 141, and a collecting pipe 142b after the two air cooling unit outlet pipes 142a are connected.

The air cooling unit outlet pipe 142a penetrates the central plate 141b of the surrounding plate 141 of each air cooling unit 150, and guides the non-condensed gas such as air accumulated in the surrounding plate 141 upward. Further, the collecting pipe 142b is connected to two air cooling unit outlet pipes 142a, and guides the non-condensed gas to an external steam-driven air extractor or vacuum pump (not shown).

As shown in FIG. 4, the axial position where the extraction pipe 142 is connected to the surrounding plate 141 is a position close to the inlet side end plate 113a. That is, since the steam from the turbine exhaust in the condenser main body 110 is in a saturated state, the relationship between the temperature and the pressure is one-to-one, and the cooling water is on the inlet side end plate 113a side where the cooling water temperature is low. The saturated vapor pressure is lower than that of the outlet side end plate 113b, which has a high temperature. As a result, the concentration of the non-condensable gas is relatively higher on the inlet side end plate 113a side than on the outlet side end plate 113b side. Therefore, it is more efficient to extract the non-condensable gas from the surrounding plate 141 located near the inlet side end plate 113a.

Further, since the non-condensable gas extracted from the position near the inlet side end plate 113a has a relatively low temperature, the specific volume of the non-condensable gas including the turbine exhaust is relatively small, and as a result, the flow velocity is relative. Therefore, the pressure loss due to the flow after the extraction pipe 142 can be reduced. By suppressing this pressure loss to a low level, the pressure of the multi-tube condenser 100 on the upstream side can be suppressed to a low level.

The multi-tube condenser 100 has two air cooling units 150 arranged within the tube bundle region 125. Each air cooling unit 150 has a surrounding plate 141 and a plurality of cooling pipes 123 surrounded by the surrounding plate 141.

As shown in FIG. 3, the two air cooling units 150 are arranged in the same tube bundle region 125.

A plurality of cooling pipes 123 are arranged in parallel with each other in the tube bundle region 125 shown by a broken line in FIG. 3, and a plurality of flow paths (not shown) are arranged from the periphery of the tube bundle region 125 toward the two air cooling portions 150. Is formed. Turbine exhaust steam flows into the pipe bundle 124 from around the pipe bundle region 125, and exchanges heat with the cooling medium in the cooling pipe 123 between the cooling pipes 123 centering on a plurality of flow paths formed in the pipe bundle 124. While flowing toward each air cooling unit 150.

The height positions of the two air cooling units 150 coincide with each other, and are arranged in the height direction at a position lower than the central position of the tube bundle region 125. This is because the momentum of the flow of the turbine exhaust steam flowing in from the periphery of the tube bundle region 125 differs between the flow flowing from above and the flow flowing in from below. That is, what flows in from above directly flows in along the downward flow of the exhaust gas of the turbine 1, whereas the flow from below passes through the flow path between the pipe bundle region 125 and the side body 112. This is because the flow direction is changed upward after the flow. That is, the distance from the upper side to the position of the stagnation point where the flow flowing into the pipe bundle 124 from above and the flow flowing into the pipe bundle 124 from the lower side meet each other and stagnate is the distance from the lower side. This is because it is longer than that.

Further, the two air cooling units 150 are arranged at positions where the distances from the horizontal boundaries of the respective tube bundle regions 125 are equal to each other in the horizontal direction. That is, they are arranged at equal distances from the virtual central surface of the tube bundle region 125. As a result, the cross-sectional shape of the tube bundle region 125 including the air cooling unit 125 is also symmetrical.

In the cross-sectional view shown in FIG. 3, the position of each air cooling unit 150 in the tube bundle region 125 is based on the inflow angle and inflow speed of the turbine exhaust steam flowing into the tube bundle 124 from each around the tube bundle region 125. It is determined. That is, after grasping the situation until each flow of the turbine exhaust steam flows into the pipe bundle 124 and stagnates by analysis or a simulation experiment, the stagnation point, that is, the position where the flow stays is determined based on the result. By determining the position of the air cooling unit 150, higher cooling efficiency and condensation performance can be ensured.

Further, by providing a plurality of air cooling units 150, the redundancy of air discharge is improved. That is, even if the turbine exhaust state changes, the condensation performance can be maintained without a significant change from the planned performance. Further, even if it is placed when the in-leakage of air from the outside increases, the influence on the performance deterioration becomes small.

Further, by providing a plurality of air cooling units 150, the steam flow rate to one air cooling unit 150 is reduced and the steam flow velocity is slowed down, so that the pressure loss of the steam flow in the multi-tube condenser 100 is reduced. It is reduced, and it becomes possible to make the inside of the multi-tube condenser 100 a higher vacuum. As a result, turbine efficiency increases.

[Second Embodiment]
FIG. 5 is a cross-sectional view showing the internal configuration of the multi-tube condenser according to the second embodiment.

In the present embodiment, three air cooling units 150 are provided in the same tube bundle region 125.

When the ratio of the dimension in the width direction to the dimension in the height direction of the tube bundle region 125 becomes large, the inflow path in the lateral direction becomes relatively long, so that the inflow amount from the lateral direction is reduced. However, the cooling efficiency is reduced. This embodiment is particularly effective in such cases.

[Third Embodiment]
FIG. 6 is a cross-sectional view showing the internal configuration of the multi-tube condenser according to the third embodiment. FIG. 6 shows a case where two air cooling units 150a and two air cooling units 150b are provided in each of the pipe bundle region 125a and the pipe bundle region 125b when two pipe bundle regions 125a and 125b are present. There is.

In the case where two tube bundle regions exist, the horizontal length may be too wide, especially in one tube bundle region.

In another case where two tube bundle regions exist, the direction of the flow of the cooling medium in the cooling tube 123 in one tube bundle area 125a and the direction of the flow in the cooling tube 123 in the other tube bundle area 125b are , May be the opposite of each other. Such a case is affected by the fact that when the cooling pipes are arranged parallel to the turbine shaft, the temperatures of the cooling media that cool the exhaust steam of the two low-pressure turbines are different in the flow direction of only one of them. Is effective when is large.

As described above, even when the two tube bundle regions 125a and 125b are present, the condensing performance of the multi-tube condenser 100 can be ensured by providing a plurality of air cooling portions for each.

[Fourth Embodiment]
FIG. 7 is a cross-sectional view showing the configuration of a multi-tube condenser in the case of the side exhaust system according to the fourth embodiment.

In the case of the side exhaust system shown in FIG. 7, the multi-tube condenser 101 is arranged on the side of the steam turbine 1. Therefore, the condenser duct 105 of the multi-tube condenser 101 is arranged so that the turbine exhaust steam from the steam turbine 1 flows into the tube bundle region 125c of the multi-tube condenser 101 from the lateral direction. Has been done.

FIG. 8 is a cross-sectional view showing the internal configuration of the multi-tube condenser in the case of the side exhaust system according to the fourth embodiment.

The tube bundle region 125c is formed so that the area for receiving the turbine exhaust steam from the steam turbine 1, that is, the area on the plane perpendicular to the flow direction is large. In FIG. 8, the tube bundle region 125c is formed so as to have a large vertical length.

Therefore, in the present embodiment, two air cooling units 150 are provided above and below in the wide direction of the tube bundle region 125c, that is, in FIG.

Assuming that the position viewed from the steam turbine 1 side is called the longitudinal position, the longitudinal position and the horizontal position of the two air cooling units 150 are the distances from the steam turbine 1 side of the duct bundle region 125c, for example. The distance of the condenser main body 110 from the connection portion with the condenser duct 105 is the same as that of the first to third embodiments for the same reason.

Further, the longitudinal positions of the two air cooling portions 150 are on the side opposite to the steam turbine 1 side from the longitudinal direction of the tube bundle region 125, that is, the center in the horizontal direction.

The configuration of each air cooling unit is the same as that of the first to third embodiments, and the surrounding plate 141 is opened downward.

As described above, even in the case of the side exhaust system, the condensing performance of the multi-tube condenser 101 can be ensured by providing the plurality of air cooling units 150 in the pipe bundle region 125c.

[Other Embodiments]
Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention.

For example, FIG. 1 shows a case where the cooling pipes 123 are arranged in a direction parallel to the rotating shaft 2a of the rotating portion 2 of the steam turbine 1, but the present invention is not limited to this. For example, the low-pressure feed water heater 4 of FIG. 1 may be arranged in parallel in the extending direction. In this case, the inlet side water chamber and the outlet side water chamber are arranged in directions orthogonal to those shown in FIG. 1, that is, at positions in front of and behind FIG. 1, respectively.

Further, in the embodiment, a case where the shape of the tube bundle region is symmetrical with respect to the central virtual surface and a case where the air cooling portion is also arranged at a symmetrical position is shown as an example. , Not limited to this. That is, even in the case of a tube bundle region having a shape that does not have symmetry, a plurality of air cooling units are installed there, and each air is installed so that the region in which the steam flowing in from the periphery of the pipe bundle region stays is the smallest. By determining the position of the cooling unit, the cooling efficiency and condensation performance can be maximized.

Moreover, you may combine the features of each embodiment. For example, the features of the second embodiment may be combined with the third embodiment. Alternatively, the fourth embodiment may be combined with the features of the second embodiment or the third embodiment, or the features of the second embodiment and the features of the third embodiment, respectively.

In addition, the embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention.

The embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Steam turbine, 2 ... Rotating part, 3 ... External casing, 4 ... Low pressure water supply heater, 5 ... Circulating water inlet pipe, 6 ... Circulating water outlet pipe, 8 ... Condensate pipe, 100, 101 ... Multi-pipe type Water device, 105 ... Condenser duct, 110 ... Condenser body, 112 ... Side body, 113 ... End plate, 113a ... Inlet side end plate, 113b ... Outlet side end plate, 114 ... Bottom plate, 120 ... Cooling structure, 121 ... inlet side water chamber, 121a ... cooling water inlet nozzle, 122 ... outlet side water chamber, 122a ... cooling water outlet nozzle, 123 ... cooling pipe, 124 ... pipe bundle, 125, 125a, 125b, 125c ... pipe bundle area , 126 ... Condensate support plate, 130 ... Condensate outlet, 140 ... Air extraction, 141 ... Surrounding plate, 141a ... Opposing plate, 141b ... Central plate, 142 ... Extraction pipe, 142a ... Air cooling outlet pipe, 142b ... Collecting pipe, 150, 150a, 150b ... Air cooling unit

Claims (5)

A multi-tube condenser that condenses turbine exhaust steam discharged from a steam turbine with a cooling medium.
The condenser body that receives the turbine exhaust steam and
A tube bundle having a plurality of cooling pipes arranged in the condenser main body to serve as a flow path for the cooling medium and arranged in parallel with each other.
In the tube bundle area where the tube bundle is arranged, an air cooling unit that collects the discharged non-condensed gas and
An extraction pipe that serves as a flow path for the non-condensed gas from the air cooling unit,
With
A plurality of the air cooling units are provided in one of the tube bundle regions.
A multi-tube condenser that features this. The air cooling unit has a surrounding plate that is supported by the inlet side pipe plate and the outlet side pipe plate and is open downward.
The extraction position of the extraction pipe from the surrounding plate of the air cooling portion is in the vicinity of the inlet side pipe plate.
The multi-tube condenser according to claim 1. The condenser main body is formed with an inlet side pipe plate and an outlet side pipe plate of the plurality of cooling pipes.
The inlet side water chamber attached to the outside of the inlet side pipe plate and
The outlet side water chamber attached to the outside of the outlet side pipe plate and
The multi-tube condenser according to claim 1 or 2, further comprising. Any of claims 1 to 3, wherein the plurality of air cooling units provided for the one tube bundle region are arranged at positions where the steam flow stays in the tube bundle region. The multi-tube condenser described in item 1. The plurality of air cooling units provided in the one tube bundle region are
The distances from the steam turbine side are the same as each other, and the longitudinal position is on the side opposite to the steam turbine side from the center of the tube bundle region in the longitudinal direction.
The multi-tube condenser according to any one of claims 1 to 3, wherein the condenser is characterized in that.

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