JPH08226776A - Condensing apparatus and generating plant - Google Patents

Abstract

PURPOSE: To reduce pressure loss and efficiently remove a non-condensed gas. CONSTITUTION: The reference numeral 1 designates a tube bundle, 11 an outer periphery of the tube bundle, 12 flow passages, 13 tube banks, 2 an inlet of steam flow, 3 an extraction port of non-condensed gas, and 5 a bottom surface of a vessel. The tube bundle 1 is positioned away from a side wall 4 of the vessel and the bottom surface of the vessel so as to enable taking in steam from every quarter and decreasing a speed of steam. The extraction port 3 is disposed below a center of gravity of the tube bundle 1, and the plurality of flow passages 12 are formed above the extraction port 3 to extend toward the extraction port 3 from the outer periphery 11 of the tube bundle. The flow passages 12 have tip ends thereof at the outer periphery 11, and are widened in width toward the tip ends. Further, area ratios and lengths of the flow passages become larger toward a central axis of the tube bundle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condenser, and more particularly to a condenser suitable for use in condensers of nuclear and thermal power plants, condensers of chemical plants and the like.

[0002]

2. Description of the Related Art For example, in a condenser of a nuclear power plant or a thermal power plant, a water chamber for introducing cooling water is provided at both ends of a cooling pipe, and a steam inlet is provided so as to be orthogonal to the cooling pipe. Flow perpendicular to the cooling tubes. Since a large number of cooling pipes of 1000 to 10000 are usually used in the condenser tube nest, it is an important issue to reduce the pressure loss by the cooling tube in order to introduce the steam into the nest.

On the other hand, non-condensable gas such as air in the atmosphere is mixed in the steam, and the non-condensable gas is concentrated as the steam condenses and collects in the low pressure portion of the tube nest. When the non-condensed gas stagnates inside the tube nest, it shields the surface of the cooling pipe and significantly impedes the vapor condensation. Therefore, the removal of non-condensable gas is also an important issue.

Since the pressure loss in the tube nest and the stagnation region of the non-condensable gas are affected by the flow of steam, they largely depend on the shape of the tube nest in the cross section orthogonal to the cooling pipe. Therefore, various tube nest shapes have been proposed.

As a first conventional example, Japanese Patent Laid-Open No. 61-114087
No. 1,704,484, DE 7,539,721, a flow path for reducing pressure loss is provided at the outer periphery of a tube nest, and an extraction pipe or an opening (hereinafter referred to as an extraction region) for extracting non-condensable gas is not provided. A tube nest with a pressure equalization zone for guiding condensed gas is described.

Although the shapes thereof are various, the cooling pipes are arranged around the pressure equalizing region in a layer shape having a substantially constant thickness, and are based on the following common concept. That is, if the cooling pipes are arranged in a layer perpendicular to the inflow direction with respect to the uniformly inflowing steam, the flow of the steam is one-dimensional, the steam condenses from the surface of the bed, and the non-condensed gas flows to the back of the bed. It is concentrated and guided to the extraction tube by the pressure equalizing zone provided behind the bed. However, in this shape, the surface area of the tube nest is limited by the opening width of the steam and the pressure loss increases, so that the layer is deformed two-dimensionally while maintaining the thickness of the layer.

As a second conventional example, Japanese Patent Laid-Open No. 4-244
Japanese Patent No. 589 describes a tube nest shape in which a non-condensable gas is collected in a low pressure portion by providing a plurality of flow paths in a layer and reducing the flow path width in an arithmetic progression.

Further, as a third conventional example, Japanese Patent Laid-Open No. 2-242
Japanese Patent Laid-Open No. 088 describes a tube nest shape in which a layer is divided into a plurality of tube nests by a flow passage, and non-condensable gas is collected in a low pressure portion by a change in cross-sectional area of one flow passage.

[0009]

In the first conventional example, 2
The non-condensable gas does not always gather in the pressure equalizing region behind the bed when it is deformed dimensionally, and the pressure equalizing region does not work effectively when the non-condensing gas stays away from the extraction region. Furthermore, the vapor velocity is slow inside the tube nest where the pressure equalizing region is provided, and the pressure equalizing region is not effective in reducing the pressure loss.

In the second and third conventional examples, the non-condensable gas collects in the low pressure portion, but the flow passage is indispensable and a cooling pipe cannot be arranged in the flow passage, so that it is not suitable for a compact condenser. . Moreover, since the concentration of the non-condensable gas varies depending on the path of the vapor flow, the non-condensable gas is mixed in the low pressure portion, and the stagnant region of the non-condensable gas cannot be sufficiently reduced. Further, in the second conventional example, it becomes difficult to collect the non-condensable gas in the direction of the flow channel when the flow channel length becomes long, and in the third conventional example, a space for providing an air extraction system is required for each individual tube nest. Therefore, incidental equipment will increase. The problem with these conventional techniques is that the shape based on the one-dimensional theory is used.

An object of the present invention is to provide a compact condensing device capable of reducing pressure loss and efficiently removing noncondensable gas, and a power plant using the same.

[0012]

In order to achieve the above object, the present invention provides an inlet for introducing steam, a plurality of cooling pipes for condensing the steam flowing from the inlet, and condensation by the cooling pipes. In a condensing device having an outlet for letting out the condensate generated in step 1, and at least one extraction port for extracting the non-condensable gas mixed in the steam, a suction region for the vapor formed near the extraction port, and at least the vapor In a main flow direction of a plurality of the plurality of elements arranged so that the flow rate distribution (or the cross-sectional area distribution of a plurality of areas) defined by the shape of the suction region and the streamline of the suction flow to the extraction port is equalized. It is equipped with a cooling pipe.

Further, according to the present invention, a pipe having an inflow port for introducing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, and at least one extraction port for extracting non-condensable gas mixed in the steam. In a condenser comprising a nest and an outlet for letting out a condensate generated by condensation by the tube nest, the extraction port is located on the opposite side to the inlet with respect to the center of gravity of the outer circumference of the tube nest, and the tube nest is A plurality of flow passages extending from the outer periphery of the tube nest to the extraction port are provided, and the length of the flow passages is increased as it is closer to the reference line extending from the extraction port toward the inflow port side in parallel with the main flow direction of steam.

Further, according to the present invention, a pipe having an inflow port for introducing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, and at least one extraction port for extracting non-condensable gas mixed in the steam. In a condensing device including a nest and an outlet for letting out a condensate produced by condensation by the tube nest, the tube nest has a plurality of flow paths located on the inlet side and extending from the outer circumference of the tube nest to the extraction port. A first region and a second region adjacent to the first region and having the extraction ports and having densely arranged cooling pipes are provided, and the length of the flow path is in the main flow direction of steam. It is made longer as it is parallel to and is closer to the reference line from the extraction port toward the inlet side.

Further, according to the present invention, a pipe having an inflow port for introducing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, and at least one extraction port for extracting non-condensable gas mixed in the steam. In a condenser comprising a nest and an outlet for letting out a condensate generated by condensation by the tube nest, the tube nest is a dense region in which cooling pipes are densely arranged around the extraction port, and a tube nest. A radiation region having a plurality of flow paths from the outer periphery to the extraction port is provided, and the plurality of flow paths are formed so that the flow rates of vapors flowing through the respective flow paths are substantially equal.

Further, the present invention is a power generation plant comprising a steam turbine for generating electric power using steam and a condenser for condensing steam discharged from the steam turbine, wherein the condenser is the above-mentioned condenser. It is equipped with a condenser.

The present invention is obtained by optimizing the positions of the flow path and the extraction region in the tube nest based on the two-dimensional theory that can directly represent the two-dimensional tube nest shape of the condenser. First, the principle of the present invention will be described by taking a condenser of a nuclear power plant or a thermal power plant as an example. In a nuclear power plant or a thermal power plant, a steam flow passing around a rotating blade row in a turbine flows into a condenser via a turbine exhaust chamber and is condensed in a tube nest of the condenser. For this reason, the flow in the condenser inlet has a complicated distribution, but the turbine exhaust chamber usually has a structure that can reduce uneven flow in the condenser inlet, so here we simplify the condenser. It is assumed that the flow at the inlet of the vessel is almost uniform.

FIG. 3 shows the concept of the suction flow model which is the basis of the two-dimensional theory. Vapor condenses on the surfaces of multiple cooling tubes that make up the tube nest, but in order to collect the non-condensable gas mixed with the steam in the extraction area, suction that replaces the condensation on the cooling tube surface with the suction in the extraction area Consider the flow that involves. In FIG. 3, the streamlines are drawn at regular intervals in the inflow section, and the flow in the inflow section is uniform, so the flow rates between adjacent streamlines are all the same.

As shown in FIG. 4, the installation area of the cooling pipe required to condense the flow rate between the streamlines is determined. That is,
For each streamline, the suction point is used as the starting point and the area is divided to obtain a shape that has a constant area, and the envelope that connects the end points (equal area line)
Ask for. For example, the areas of the two shaded areas in FIG. 4 are equal. This equal area line can be found on the figure,
Mathematically, one variable for the area can be selected as the stream function corresponding to the streamline, and one variable can be obtained as the stream potential orthogonal to the streamline.

The amount of condensation in the cooling pipe varies from one pipe to another, and is affected by the saturated steam temperature and steam velocity that decrease with pressure loss in the tube nest, and the heat transfer coefficient that changes depending on the noncondensable gas concentration. However, the final purpose here is to reduce the pressure loss and remove the non-condensable gas, and in the case of the condensation of the vapor containing only a small amount of the non-condensable gas, the heat transfer coefficient is dominated by the liquid film on the tube surface and the vapor velocity. Since the effect of is small, a uniform amount of condensation can be assumed. Therefore, a certain number of cooling pipes are required to condense a constant flow of steam, and the area previously obtained is the area required when the cooling pipes are densely arranged as a regular staggered or square tube group. , Equal area lines represent the outer peripheral shape of the tube nest. Hereinafter, this tube nest is referred to as a tube nest consisting of only a dense portion.

When a tube nest consisting of only a dense portion is used in a large condenser, pressure loss is large and steam cannot reach the center of the tube nest. Therefore, it is necessary to provide a flow path in the tube nest. FIG. 5 shows a method of providing a flow path in a tube nest composed of only a dense portion. As a way of providing the flow path, in order to reduce a resistance to the suction flow by moving a part of the tube group of the dense portion to the outside of the tube nest,
A flow path is provided along the streamline. At this time, in order to condense a constant flow rate of steam between streamlines, the number of cooling pipes between streamlines is made constant. That is, the area of the tube group between the streamlines is made constant.

The spacing of the streamlines is arbitrary, but it is necessary to keep the shape of the entire tube nest, that is, the distribution of the cooling tubes, and to narrow the spacing to some extent. But,
If the number of flow paths is not narrowed below the pitch of the tube group and the streamline intervals are narrowed, it is not a good idea because friction increases on the surface of the cooling tubes lined up on the side surfaces of the flow paths. In consideration of such a point, it is appropriate to set the interval divided by about 10 streamlines as shown in FIG.

Since the steam velocity is not uniform on the outer periphery of the tube nest composed only of the dense portion and is inversely proportional to the interval of the streamlines, the steam velocity is high in the upper part where the interval is narrow. Further, in the upper part as well, the steam velocity is higher as it is closer to the central axis (the reference line parallel to the main flow direction of steam and extending from the extraction region toward the inlet side). Since the pressure loss increases in proportion to the square of the velocity, a flow passage is provided in the upper portion where the steam velocity is high, and the flow passage ratio between the streamlines is increased in proportion to the steam velocity and closer to the central axis. Since a constant streamline interval is used as a basic unit, the flow path length becomes longer as it approaches the central axis, and the tip of the tube group also extends upward. When the tip of the tube group extends upward, the flow line is deformed due to the resistance of the tube group and pressure loss occurs, but the deformation of the flow line is stopped minutely by making the tube group sparser in the upper part of the nest where the flow velocity is faster. be able to.

Next, consider extending the flow path to the vicinity of the suction point. Usually, staggered or square regular arrangements are used in condenser tubes, but it is not easy to use regular tubes to follow the flow path along a curved suction flow streamline. Therefore, consider a method of extending the flow path in a straight line as shown in FIG.

Although the shape of the flow path defines the actual streamline, FIG. 6 shows the ideal streamline of the suction flow as before. Reference numerals 13a to 13m in the same figure represent a group of tubes for condensing a constant flow rate of steam from between the corresponding streamlines. Since the amount of steam at a constant flow rate does not change even if the flow path is extended, the area of each tube group 13a to 13m is made constant. At the upper part of the tube nest where the flow path exists, it is difficult to arrange the tube group in line with the ideal flow line of the suction flow. Therefore, as shown in FIG. The flow paths are approximated by and the tube groups are arranged so as to form such flow paths.

On the other hand, in the lower part of the tube nest where the flow path does not exist, the flow is not regulated by the flow path, but since the upper tube group enters the lower part due to the above-mentioned deformation of the upper part of the tube nest, each tube group The tube groups are arranged so as to be displaced to the outside of the equal-area line so that the area of is constant. Even if such a tube group arrangement is used, since the flow velocity is extremely slow in the lower part of the tube nest and the influence of the tube group shape on the pressure loss is small, it is possible to take a somewhat free shape if the area is constant.

With the tube nest shape determined as described above, a flow path can be constructed which can condense the steam without disturbing the steam flow flowing into the upper part of the tube nest, so that the pressure loss can be reduced. Further, since the noncondensable gas can be collected at the suction point which is the end of the suction flow, the noncondensable gas can be efficiently removed and the heat transfer performance can be greatly improved. Furthermore, since there is no conventional pressure equalizing area, a compact condenser (condenser) can be obtained.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a condenser to which the present invention is applied. The condenser includes a steam inlet 2, a tube nest 1 for condensing steam 1, a noncondensable gas extraction tube 30 for extracting noncondensable gas,
It is composed of the condensate outlet 6, the side wall 4 of the container, and the like. Tube nest 1
Is 1000 to 100 extending in the horizontal direction (x direction in FIG. 2).
It consists of 00 cooling pipes (not shown) and is supported by the support plate 14. The cooling water flows from the cooling water inflow port 80, flows through the water chamber 81, and flows in the cooling pipe of the tube nest 1. Tube nest 1 is 1a
And 1b, the performance of the condenser can be maintained even if a failure occurs in one of the two systems.

The steam exhausted from the turbine (not shown) flows into the condenser from the upper side of the steam inlet 2, is condensed in the tube nest 1, and the condensed water generated by the condensation falls downward by gravity, It flows out from the condensate outlet 6. On the other hand, the uncondensed vapor and the non-condensed gas that have not been completely condensed in the tube nest 1 are taken into the extraction pipe 30 that has a large number of holes on the surface and extends in the x direction, and the uncondensed gas located at one end in the x direction. It flows into the gas cooling unit 131. The non-condensable gas cooling unit 131 has a plurality of cooling pipes extending in the x direction inside, and most of the uncondensed vapor is condensed by the cooling pipes, and the remaining non-condensed gas is exhausted from the non-condensed gas exhaust pipe 132.
Is exhausted to the outside of the condenser. That is, the non-condensable gas cooling unit 131 plays a role of condensing the uncondensed vapor that could not be completely condensed in the tube nest 1.

The non-condensable gas cooling part 131 is provided not only at one end in the x direction as in the present embodiment, but also in the entire x direction, or the extraction pipe 30 is extended to the outside of the condenser. The non-condensable gas cooling unit 131 may be provided separately from the condenser.

Next, a method for determining the aspect ratio of the tube nest (tube nest height / tube nest width) will be described. FIG. 7 shows the aspect ratio of the tube nest obtained by the suction theory described above. In the figure, the vertical axis represents the aspect ratio of the tube nest, and the horizontal axis represents the ratio of the tube nest width to the container width. When two systems of tube nests are provided in the container as shown in FIG. 2, the container width is defined as the distance between the container side wall 4 and the symmetrical plane of the two systems of tube nests. Of the two curves shown in the same figure, the lower side represents the aspect ratio of the nest containing only the dense portion, and the upper side represents the aspect ratio of the nest having a flow path. Thus, the aspect ratio of the tube nest with respect to the container width can be determined by using FIG. 7 obtained by the suction theory.

For example, when the tube nest width is sufficiently smaller than the container width, the influence of the container side wall is small, so that the shape of the tube nest consisting of only the dense portion approaches a concentric circle, and the aspect of the tube nest consisting of only the dense portion. The ratio will be about 1. Further, at this time, since the non-uniformity of the vapor velocity at the outer periphery of the dense portion is small, in order to maintain the balance of the pressure loss and reduce the suction point to low pressure,
It is preferable to provide the channels uniformly in the circumferential direction. Considering this condition, the aspect ratio of the tube nest having the flow path is also about 1. On the other hand, when the ratio of the tube nest width to the container width exceeds 0.5, the side wall of the container appears and the aspect ratio of the tube nest composed of only the dense portion becomes larger than 1. In this case, the non-uniformity of the vapor velocity at the outer periphery of the dense portion increases, and especially the vapor velocity at the upper part increases. Therefore, in order to provide the channel by the method described in FIGS. It is necessary to make the aspect ratio of the tube nest that is abruptly larger than that of the tube nest that is composed only of dense parts.

Here, the optimum value of the aspect ratio of the tube nest having the flow passage will be examined. As described above, the width of the tube nest causes the influence of the container wall, and as a result, the vapor velocity becomes non-uniform, and the aspect ratio of the tube nest having only the dense portion is determined. Therefore, as an index showing the non-uniformity of vapor velocity,
It is possible to use the aspect ratio of the tube nest that is composed only of dense parts. Hereinafter, of the tube nest having the flow passage, the upper region where the flow passage exists is referred to as a radiation portion.

It is considered that the vapor velocity at the upper part of the tube nest increases almost in proportion to the aspect ratio of the tube nest composed of only the dense portion. Also, the pressure loss is proportional to the product of the resistance coefficient of the tube nest and the square of the steam velocity. Therefore, in order to suppress the pressure loss in the upper part of the tube nest to be equal to that in the lower part of the tube nest, it is necessary to make the resistance coefficient in the upper part of the tube nest inversely proportional to the square of the steam velocity. In other words, it is necessary to make the resistance coefficient of the upper part of the tube nest inversely proportional to the square of the aspect ratio of the tube nest composed of only the dense portion.

To this end, the number of cooling tubes is kept constant and
The area of the radiating part is increased in proportion to the square of the aspect ratio of the tube nest consisting of only dense parts, and the occupancy of the cooling pipe in the radiating part is inversely proportional to the square of the aspect ratio of the tube nest consisting of only dense parts. Let Since the resistance coefficient in the upper part of the tube nest is proportional to the occupancy rate of the cooling pipe in the radiating portion, the resistance coefficient in the upper part of the tube nest can be reduced in inverse proportion to the square of the aspect ratio of the tube nest composed of only the dense portion. If the ratio of the radiating portion to the tube nest having the flow channel is large, it is preferable that the aspect ratio of the tube nest having the flow channel is set to the square of the aspect ratio of the tube nest having only the dense portion.

The above examination is qualitative, and the optimum value needs to have an appropriate width. However, as the aspect ratio of the tube nest having the flow path, the aspect ratio of the tube nest having only the dense portion is 2 The raised curve is shown in FIG.

Practically, there is a restriction on the arrangement of the container width, and if the container width is made extremely small to increase the aspect ratio of the tube nest, the nonuniformity of the vapor velocity at the outer periphery of the tube nest becomes remarkable. Since it becomes difficult to equalize the pressure loss even if the number of radiating portions is increased, the ratio of the tube nest width to the container width is preferably in the range of about 0.5 to 0.8. This is an aspect ratio of a tube nest consisting only of dense parts of 1.13-1.
The aspect ratio of the tube nest having the flow path in the range of 75 corresponds to the range of 1.28 to 3.06. On the other hand, in a small condenser, the aspect ratio of the tube nest may be less than 1 because the number of cooling tubes is small.

Examples in which dot-like suction is provided and the aspect ratio of the tube nest exceeds 1 and those in which the aspect ratio of the tube nest is less than 1 will be described below.

FIG. 1 shows a cross section of a first embodiment of a tube nest to which the present invention is applied. In the figure, 1 is a tube nest, 11 is an outer circumference of the tube nest,
12 is a flow path, 13 is a tube group, 2 is a steam inlet, 3 is a non-condensable gas extraction port, and 5 is a container bottom. When one system of tube nests is provided in the container, 4 represents the side wall of the container, and when two system of tube nests are provided in the container, 4 represents the plane of symmetry between the container side wall and the two system nests. In FIG. 1, the tube nest shape determined in FIG. 6 is used as it is, and the extraction port 3 is provided at the position of the suction point.

The tube nest 1 is located away from the container side wall 4 and the container bottom surface 5 so that the steam can be taken in from all directions and the steam velocity can be reduced. The extraction port 3 is below the center of gravity of the outer circumference 11 of the tube nest, and a plurality of flow paths 12 extending from the outer circumference 11 of the tube nest to the extraction opening 3 are formed above the extraction port 3. The flow path 12 has a tip on the outer circumference 11 of the tube nest, and the width of the flow path is wider toward the tip. In other words, the flow path 12 is the outer circumference 11 of the tube nest.
Has an inflow port, and the width of the flow path becomes narrower as it is closer to the extraction port 3. Furthermore, the area ratio and the length of the flow path are larger as the flow path is closer to the central axis of the tube nest.

With such a structure, since the steam flows in from the steam inflow port 2, the steam velocity at the upper portion of the tube nest is high, but the flow velocity ratio is larger at the higher portion of the tube nest.
The pressure loss can be reduced. Further, since the extraction port 3 is arranged at the suction point where the non-condensable gas mixed in the vapor is condensed and condensed by the condensation of the vapor, the stagnation of the non-condensable gas does not occur.

Next, a second embodiment of the tube nest to which the present invention is applied will be described with reference to FIG. FIG. 8 shows a cross section of the second embodiment, and the same components as those in the first embodiment are designated by the same reference numerals. In this embodiment, the auxiliary flow path 12a is also provided in the lower portion of the tube nest 1 having a low flow velocity. That is, the flow path 12 is provided at a constant flow rate in the upper part where the steam speed is fast, but the steam speed is extremely slow in the lower part, so that the pressure loss in the region where the tube group is dense is reduced according to the slow steam speed. In addition, a plurality of short flow paths 12a are provided for a constant flow rate.

Since the vapor velocity is originally low in the lower portion of the tube nest 1, the width of the lower flow passage 12a may be slightly widened at the tip, and in this embodiment, the width is constant. Further, in the lower part where the steam velocity is low, the shape of the outer periphery 11 of the tube nest can be freely set by keeping the area of the tube group constant, so that in the present embodiment, it can be arranged most compactly in the rectangular condenser container. The shape of the lower tube nest is close to a rectangle.

The characteristics of the shape of the flow path 12 of this embodiment are summarized as follows:
The width of the flow path is wider toward the tip, with the outer periphery 11 of the tube nest being the front end, and the area ratio and length of the flow path are larger as they are closer to the central axis above the extraction port 3 (central axis on the steam inlet side), and It decreases in the circumferential direction from the central axis to the central axis below the extraction port 3 (central axis on the bottom surface side of the container). In the vicinity of the extraction port 3, a concentric, dense tube group 13 surrounding the extraction port 3 is provided. With such a configuration, the pressure loss can be reduced even in the lower portion of the tube nest, and the performance can be further improved.

Next, a third embodiment of the tube nest to which the present invention is applied will be described with reference to FIG. FIG. 9 shows a cross section of the third embodiment, and the same components as those of the second embodiment are designated by the same reference numerals. In this embodiment, the tube group 13 is provided near the extraction port 3.
Is not provided, but the space 14 is provided. Space 14 is extraction port 3
Is welded to the support plate of the cooling pipe, and a distance of 3 to 5 times the diameter of the cooling pipe (for example, 9 to 15 cm for a cooling pipe diameter of 3 cm) is usually secured as a welding space.
As shown in the figure, by forming the space 14 in a concentric shape, a compact condenser can be obtained.

Next, a fourth embodiment of the tube nest to which the present invention is applied will be described with reference to FIG. FIG. 10 shows a cross section of the fourth embodiment, and the same components as those in the second embodiment are designated by the same reference numerals. In this embodiment, the flow path 12 is also provided on the central axis on the steam inlet side above the extraction port 3. Usually, the steam inlet 2 of the condenser is provided on the upper side in the direction of gravity, and the condensate produced by condensation of the steam falls downward due to gravity. Therefore, by making the flow path 12 instead of the tube group 13 on the central axis on the steam inlet side, it is possible to reduce the falling amount of the condensed liquid and to prevent the dropped condensed liquid from blocking the extraction port 3.
The non-condensable gas can be extracted more reliably.

Next, a fifth embodiment of the tube nest to which the present invention is applied will be described with reference to FIG. FIG. 11 shows a cross section of the fifth embodiment, and the same components as those in the second embodiment are designated by the same reference numerals. In this embodiment, the noncondensable gas cooling unit 131 is provided above the extraction port 3 to cool the noncondensable gas extracted from the extraction port 3. Non-condensable gas cooling unit 1
Reference numeral 31 is provided in a partial region in the length direction (x direction in FIG. 2) of the cooling pipe, and is configured so that the non-condensable gas extracted through the extraction port 3 flows in. The non-condensed gas and the uncondensed vapor extracted at the extraction port 3 flow into the non-condensed gas cooling unit 131, where the uncondensed vapor is condensed by being cooled, and only the non-condensed gas is exhausted from the non-condensed gas exhaust system. It is exhausted to (not shown).

Further, in the present embodiment, the staggered arrangement having the regular triangles as a basic element is used as the arrangement of the tube group 13 so that the cooling pipes 130 can be densely packed and many flow paths can be taken. Further, by setting one side of the equilateral triangle in which the cooling pipe 130 is arranged to be the inflow direction of steam (vertical direction in FIG. 11), it is possible to secure a constant flow channel width even if the flow channel ratio is reduced. It greatly contributes to the downsizing of water containers.

Next, a sixth embodiment of the tube nest to which the present invention is applied will be described with reference to FIG. FIG. 12 shows a cross section of the sixth embodiment, and the same components as those in the fifth embodiment are designated by the same reference numerals. In this embodiment, the non-condensable gas cooling unit 131 is provided below the extraction port 3 having a low flow velocity. By arranging in this way, it is possible to minimize the influence due to the arrangement of the cooling pipes being irregular due to the noncondensable gas cooling unit 131.

The shape of the tube nest in the above embodiments is a vertically long shape having an aspect ratio of 1 or more. This is because the vapor nest is inside the condenser container with a limited suction point, the aspect ratio of the tube nest consisting of only the dense part exceeds 1, and a vertically long (longer in the vapor inflow direction) flow path is provided. The result. However, it is necessary to make the tube nest having an aspect ratio of 1 or less from the arrangement conditions of the entire power plant.

A seventh embodiment in which the present invention is applied to a tube nest having an aspect ratio of 1 or less will be described with reference to FIGS. 13 and 14. As shown in FIG. 13, by distributing the suction points as horizontally long suction areas, the aspect ratio becomes 1
The following tube nest shapes can be obtained. The tube nest shape obtained based on the suction flow model shown in FIG. 13 is as shown in FIG. 14, the same components as those in FIG. 8 are designated by the same reference numerals. According to this embodiment, the present invention can be sufficiently applied to a power plant that requires a horizontally long condenser.

The tube nest shape of this embodiment will be described in detail below. FIG. 15 shows the suction flow when the suction points are distributed as horizontal line segments (suction lines).
In the case of suction to the suction point as shown in FIG. 5, in the vicinity of the suction point, the streamlines spread radially around the suction point, and the suction flow was distributed at a substantially constant velocity. On the other hand, in the case of suction to the suction line in FIG. 15, the distance between the streamlines is narrow above the suction line and wide below the suction line, and the velocity of the suction flow is discontinuous across the suction line. Has changed to.

Considering the condensation in the tube nest, the velocity discontinuity does not occur at the end of the streamline (near the suction line) because the velocity is asymptotic to 0. A big speed difference occurs at. In the tube nest, a pressure loss occurs depending on the velocity due to the resistance, but in order to keep the end position of the flow line of the suction flow on the suction line,
The pressure losses above and below the suction line must be equal. That is, although the speed is high above the suction line,
By adjusting the flow path to reduce resistance, the pressure loss is reduced to the same extent as below the suction line, keeping the suction line at a low pressure. As a result, the end position of the actual streamline can be aligned with the suction line, and the non-condensable gas can be collected in the suction line.

FIG. 16 shows a tube nest shape based on the equal-area line of FIG. In the eighth embodiment shown in FIG. 16, one extraction port 3 is provided at the center of suction in consideration of space efficiency. In order to further collect the non-condensable gas that collects in the suction line in the extraction port 3, it is necessary to set the extraction port 3 to the lowest pressure. For this reason, the thickness of the dense portion in the upper part of the extraction port 3 in the vertical direction (vertical direction in FIG. 16) (the vertical distance between the lower end of the flow path 12 and the extraction port 3) becomes thicker as it approaches the extraction port 3. And increase the pressure loss.

FIG. 17 is a ninth embodiment in which FIG. 16 is modified so that the lower portion of the tube nest is linear. The streamline of the suction flow in FIG. 15 is approximately vertically oriented above and below the vicinity of the suction line, and the flow in the vertical direction is dominant.
In this case, since the flow in the horizontal direction (the left-right direction in FIG. 16) is small, if the tube nests are horizontally divided into regions for each of the tube groups 13 that are horizontally divided by the flow path 12, the respective regions are divided. It can be regarded as an independent area. In the embodiment shown in FIG. 17, these independent regions are moved downward as they move away from the extraction port 3. Due to such deformation of the tube nest, the suction line is deformed into an upwardly convex curve. It is difficult to define this curve itself,
The position of the extraction port 3 is located substantially at the center of the dense portion as in FIG. 16, and the vertical thickness of the dense portion including both above and below the suction line (the lower end of the flow path 12 and the lower end of the tube nest) The non-condensable gas can be collected at the extraction port 3 by increasing the distance (in the vertical direction to) toward the extraction port 3.

Next, an embodiment in which the condenser of the present invention is used in a boiling water nuclear power plant (BWR plant) will be described with reference to FIG. This BWR plant has a pressure vessel 71.
It is composed of a core 70, a high-pressure turbine 60, a low-pressure turbine 61, a condenser 10 and the like provided inside, and serves as a first condenser.
To any of the seventh to seventh embodiments are used. The steam generated in the core 70 enters the high pressure turbine 60, and flows into the condenser 10 via the low pressure turbine 61. The steam that has flowed into the condenser 10 is condensed into condensed water, and the condensed water flows into the core 70 again. The steam expands in the high-pressure turbine 60 and the low-pressure turbine 61 and enters the condenser, but the condenser 10 is required to have a large condensing capacity in order to condense a large amount of the expanded steam.

By using the condenser described in the first to seventh embodiments, a large condenser capacity can be obtained with a compact condenser, so that the entire BWR plant can be made compact and the construction cost can be reduced. it can. Further, in this condenser, since the pressure loss is small, the exhaust pressure of the turbine can be lowered, so that the pressure ratio before and after the turbine can be increased and the power generation efficiency can be improved. For example, when comparing the exhaust pressure of the turbine, it can be reduced from about 5000 Pa in the conventional BWR plant to about 4700 to 4800.

Although the present invention has been described in the present embodiment as a condenser of a BWR plant, the present invention is also applicable to a condenser of a thermal power plant, a condenser of a chemical plant and the like. The effect can be obtained.

[0059]

According to the present invention, since the vapor can be condensed without disturbing the vapor flow flowing into the condenser, the pressure loss can be reduced. Further, since the noncondensable gas can be collected at the suction point which is the end of the suction flow, the noncondensable gas can be efficiently removed and the heat transfer performance can be greatly improved. Accordingly, the power generation efficiency of the power plant can be improved. Further, since there is no conventional pressure equalizing area, a compact condenser can be obtained, and there is an effect that the construction cost of the power plant can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of a tube nest to which the present invention has been applied.

FIG. 2 is a diagram showing a condenser to which the present invention is applied.

FIG. 3 is a schematic diagram of a suction flow model showing the principle of the present invention.

FIG. 4 is a schematic diagram of a suction flow model showing the principle of the present invention.

FIG. 5 is a schematic diagram of a suction flow model showing the principle of the present invention.

FIG. 6 is a schematic diagram of a suction flow model showing the principle of the present invention.

FIG. 7 is a diagram showing a relationship between a container width obtained by a suction flow model and a tube nest aspect ratio.

FIG. 8 is a sectional view of a second embodiment of a tube nest to which the present invention has been applied.

FIG. 9 is a sectional view of a third embodiment of the tube nest to which the present invention is applied.

FIG. 10 is a sectional view of a fourth embodiment of the tube nest to which the present invention is applied.

FIG. 11 is a sectional view of a fifth embodiment of the tube nest to which the present invention is applied.

FIG. 12 is a sectional view of a sixth embodiment of the tube nest to which the present invention is applied.

FIG. 13 is a schematic diagram of a suction flow model for a tube nest having an aspect ratio of 1 or less.

FIG. 14 is a sectional view of a seventh embodiment of the tube nest to which the present invention has been applied.

FIG. 15 is a schematic diagram of a suction flow model for a tube nest having an aspect ratio of 1 or less.

FIG. 16 is a sectional view of an eighth embodiment of the tube nest according to the present invention.

FIG. 17 is a cross-sectional view of a ninth embodiment of a tube nest to which the present invention has been applied.

FIG. 18 is a diagram showing an example in which the condenser of the present invention is used in a boiling water nuclear power plant.

[Explanation of symbols]

1, 1a, 1b ... Tube nest, 2 ... Steam inlet, 3 ... Extraction port,
4 ... container side wall, 5 ... container bottom, 6 ... condensate outlet, 10 ...
Condenser, 11 ... Perimeter of tube nest, 12, 12a ... Flow path, 13 ...
Tube group, 30 ... Non-condensable gas extraction tube, 130 ... Cooling tube, 13
1 ... Noncondensable gas cooling part, 132 ... Noncondensable gas exhaust pipe.

Claims (11)

[Claims] 1. An inflow port for introducing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, an outflow port for outflowing a condensate produced by the condensation by the cooling pipes, and a mixture with the steam. In a condensing device having at least one extraction port for extracting non-condensed gas, a vapor suction region formed in the vicinity of the extraction port, and at least in the mainstream flow direction of the vapor, the shape of the suction region and the extraction port A condenser comprising a plurality of cooling pipes arranged so that a flow rate distribution defined by a flow line of a suction flow is equalized. 2. An inflow port for inflowing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, an outflow port for outflowing a condensate produced by the condensation by the cooling pipes, and a mixture with the steam. In a condensing device comprising at least one extraction port for extracting non-condensed gas, a vapor suction region formed in the vicinity of the extraction port, and a shape of the suction region and the extraction port to the extraction port at least in a mainstream flow direction of the vapor. A condenser comprising a plurality of cooling pipes arranged so that a cross-sectional area distribution of a plurality of regions defined by a flow line of a suction flow is equalized. 3. The condensing device according to claim 1, wherein a flow passage is provided in accordance with the velocity of the suction flow, and the extraction port is a low pressure part. 4. An inflow port for introducing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, and a tube nest having at least one extraction port for extracting noncondensable gas mixed in the steam, In a condensing device including an outlet for discharging a condensate generated by condensation by a tube nest, the extraction port is located on the opposite side to the inlet with respect to the center of gravity of the tube nest outer periphery, and the tube nest is from the tube nest outer periphery. A condensing device comprising a plurality of flow paths extending to an extraction port, wherein the length of the flow path is longer in parallel to a main flow direction of steam and closer to a reference line extending from the extraction port toward the inflow port side. 5. The condensing device according to claim 4, wherein the flow passage has an outer periphery of the tube nest as a front end, and the width of the flow passage is wider toward the front end side. 6. The condensing device according to claim 4, wherein the tube nest has a dense region in which the plurality of cooling pipes are densely arranged so as to surround the extraction port in a substantially concentric shape. . 7. The tube nest according to claim 4 or 5, wherein the tube nest includes a dense area surrounding the extraction port and in which a plurality of cooling tubes are densely arranged. The dense area has a substantially elliptical outer shape.
A condensing device characterized in that the thickness of the dense region in the mainstream direction is made thicker as it is closer to the extraction port. 8. An inlet for introducing steam, a plurality of cooling pipes for condensing the steam introduced from the inlet, and a tube nest having at least one extraction port for extracting non-condensable gas mixed with the steam, In a condensing device including an outlet for discharging a condensate generated by condensation by a tube nest, the extraction port is located on the opposite side to the inflow port with respect to the center of gravity of the outer circumference of the tube nest, and the tube nest is the extraction port. The cooling unit that cools the non-condensed gas extracted in step 1 and a plurality of flow paths from the outer periphery of the tube nest to the extraction port are provided. Condensing device characterized in that the closer it is to the reference line toward, the longer it is. 9. An inlet for introducing steam, a plurality of cooling pipes for condensing the steam flowing from the inlet, and a tube nest having at least one extraction port for extracting non-condensable gas mixed with the steam, A condensing device comprising: an outlet for letting out a condensate generated by condensation by a tube nest, wherein the tube nest is located on the inlet side and has a plurality of flow paths from the outer circumference of the tube nest toward the extraction port. And a second region adjacent to the first region and having the extraction ports and densely arranged cooling pipes, wherein the length of the flow path is parallel to the main flow direction of the steam and is extracted. A condensing device characterized in that it is longer as it is closer to the reference line from the mouth toward the inlet. 10. An inflow port for introducing steam, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, and a tube nest having at least one extraction port for extracting noncondensable gas mixed with the steam, In a condensing device including an outlet for discharging a condensate generated by condensation by a tube nest, the tube nest is a dense region in which cooling pipes are densely arranged around the extraction port, and the extraction is performed from the outer circumference of the tube nest. And a radiation region having a plurality of flow paths toward the mouth, wherein the plurality of flow paths are formed so that the flow rates of vapors flowing through the respective flow paths are substantially equal. 11. A power plant comprising a steam turbine for generating electric power using steam and a condenser for condensing steam discharged from the steam turbine, wherein the condenser is the condenser of claim 1. A power plant comprising the condensing device according to claim 1.