JP2003254676A - Condenser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a condenser with reduced pressure loss and improved performance by smoothly flowing steam into a tube bundle. <P>SOLUTION: This two-flow condenser is equipped with a tube bundle 3 constituted by a plurality of cooling tubes 1 for condensing steam 8 flowing in a container 4 from a flow inlet 5, and the tube bundle 3 is divided into an inlet side 11 and an outlet side 12 of cooling water circulated in the cooling tube. The tube bundle is constituted and arranged in a manner that a ratio of tube bundle widths of the inlet side 11 and the outlet side 12 of the cooling water almost corresponds to the ratio of steam condensation volumes in the tube bundle of the inlet side 11 and the outlet side 12 of the cooling water. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a condenser for condensing steam.

[0002]

2. Description of the Related Art Generally, a condenser has a container which communicates with a discharge port of a turbine, and has a tube nest composed of a large number of cooling pipes through which cooling water flows. An extraction tube is provided inside the tube nest to extract the non-condensable gas mixed with the steam. The steam is guided to the tube nest and condensed on the outer surface of the cooling tube. The uncondensed vapor and non-condensed gas are exhausted from the extraction pipe to the outside of the system by an ejector or a vacuum pump.

As one of these condensers, for example, in Japanese Unexamined Patent Publication No. 9-222284, an air discharge inner pipe communicating with an upper space of a cooling pipe nest is installed, and the air discharge pipe is arranged at an upper part or a lower part. It is described that, when installed, the heat energy loss due to the pressure loss of the steam flow is suppressed and the condenser is made compact. In addition, JP-A-1
In JP-A-0-19476, the steam passage outside the cooling tube nest is reduced in flow passage cross-sectional area as it goes downstream of the steam flow, and the steam is evenly guided to the tube nest, thereby reducing the pressure loss of the entire tube nest. The configuration that is kept is described. Further, Japanese Patent Laid-Open No. 11-101582 describes a configuration in which the non-condensable gas mixed in the steam is stably extracted even when the cooling water temperature changes.

[0004]

In the conventional condenser, the amount of steam condensed in each part of the tube nest is determined by the difference in the cooling water temperature between the cooling water inlet side and the outlet side and the distance from the steam inlet. There was variation. The variation in the amount of vapor condensed in the tube nest affects the flow of the inflowing vapor, resulting in a large pressure loss.

An object of the present invention is to provide a condenser in which steam is smoothly introduced into the tube nest portion to reduce pressure loss and improve performance.

[0006]

In order to achieve the above object, the condenser of the present invention is provided with a tube nest composed of a plurality of cooling tubes for condensing the steam that has flowed into the container from the inlet. A two-fold flow condenser that divides the tube nest into an inlet side and an outlet side of cooling water flowing in the cooling pipe, wherein the ratio of the tube nest widths of the cooling water inlet side and the outlet side is the cooling It is characterized in that these tube nests are arranged and arranged so as to substantially correspond to the ratio of the vapor condensation amounts at the water inlet side and outlet side tube nests.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 (a) is a front view of a condenser showing an embodiment of the present invention, FIG. 1 (b) is a side view thereof, and FIG. 2 is a steam temperature and cooling water at each point in the condenser. It is a figure which shows the relationship with temperature. The embodiment shown in FIG. 1 shows an example in which an axial exhaust condenser is used as the condenser.

In the condenser of the present embodiment shown in FIG. 1, a plurality of cooling pipes 1 and extraction pipes 2 constitute a tube nest 3, which is surrounded by a container 4. There is. Further, the plurality of cooling pipes 1 are arranged in a direction crossing the flow of steam flowing from the steam inlet 5. Extraction tube 2
Is installed in the tube nest 3, and the tube nest 3 is based on the position of the extraction pipe 2 and is cooled by the flow of cooling water.
It is divided into a cooling water outlet side 12, a front side 13 close to the inflow port with respect to the inflowing steam, and a back side far from the inflow port. Further, the extraction pipe 2 is provided with a plurality of nozzle holes (not shown) for extracting the non-condensable gas mixed in the vapor condensed by the plurality of cooling pipes 1.

In the tube nest 3, the cooling water inlet side 11 and the cooling water outlet side 12 and the front side 13 and the back side 14 have a plurality of streams extending toward the steam inlet 5 with the extraction tube 2 as a boundary. It has a radiation area in which the cooling pipes 1 are arranged so as to form channels. The flow path of the radiation region is composed of a plurality of flow paths 9 extending long toward the steam inlet 5 and formed substantially parallel to the side wall of the container 4. The plurality of flow paths 9 are cooling pipes 1.
By making the diameter larger than the diameter of the steam, most of the steam 8 discharged from the turbine (not shown) and flowing into the axial exhaust condenser from the steam inlet 5 can be sucked and condensed, resulting in a small pressure loss. Can improve the condensation performance.

The cooling water 15 flows in from the tube nest on the cooling water inlet side 11, flows through the inside of the cooling pipe 1, passes through the folding water chamber 10, and flows out from the tube nest on the cooling water outlet side. Steam inlet 5
The more inflowing steam 8 is condensed on the outer surface of the cooling pipe 1 forming the tube nest 3, and the condensed drain 6 flows out from the drain outlet 7. Further, the steam not condensed on the outer surface of the cooling pipe 1 and the non-condensed gas mixed in the steam are extracted by the extraction pipe 2 through a nozzle hole (not shown), and are discharged by a vacuum pump (not shown) such as an ejector. It is discharged outside the system.

If the steam temperature and the heat transfer coefficient of the cooling pipe 1 are constant and the distance x is taken in the flow direction of the cooling pipe 1 with the cooling water inlet as a reference, the relationship between the steam temperature Ts and the cooling water temperature Tc at each position is It is represented as in FIG. The temperature difference δT between the steam temperature Ts and the cooling water temperature Tc decreases exponentially as x increases. The condensation amount Gs of the condenser is Gs = K ・ S ・
It is represented by δT (K: heat transfer coefficient, S: cooling area), and since K and S are constant, the condensation amount Gs changes with δT from the cooling water inlet to the outlet, and is shown by the shaded area. .

The temperature conditions shown in the example of FIG. 2 (steam temperature Ts =
33 ° C., cooling water inlet temperature Tci = 23 ° C., cooling water outlet temperature Tco = 29 ° C.), the ratio of the amount of steam condensed between the cooling water inlet side 11 and the cooling water outlet side 12 is 1.7: 1. ,
This is almost the same in condensers for power plants.

Next, the amount of vapor condensation in the tube nests on the front side 13 and the back side 14 will be described with reference to FIG. In this embodiment, the steam inflow width on the cooling water inlet side (a shown in FIG. 1:
b) is adapted to the vapor condensation amount (a: b = 1.7: 1.0 under the conditions of the power plant described above). The amount of condensation with respect to the distance from the steam inlet 5 is shown by the area of the shaded area. In the case of axial exhaust, on the front side 13 close to the steam inlet 5, half or more (60 to 70%) of the steam is condensed because the inflowing steam is fast, the pressure loss is low and the heat transfer efficiency is good, but the back side 14 Then, the low-speed vapor (30-40%) remaining without being condensed is condensed. Therefore, the cooling pipes 1 of the tube nest 3 are arranged according to the ratio of the condensation amounts shown in FIGS. That is, the ratio of the numbers of cooling pipes arranged in the regions c and d shown in FIGS. 1 and 3 is set to 60 to 70%: 30 to 40%. Hereinafter, the analysis result of this example is shown in FIG.

FIG. 4 is an analysis and comparison of pressure distributions between the conventional cooling pipe arrangement and the arrangement of the cooling pipe 1 according to the present embodiment. In the arrangement according to the present embodiment, the tube nests 3 are compared with the conventional arrangement. The pressure at the top was reduced by 60 Pa, which was improved by 0.4 mmHg in terms of vacuum degree.

As described above, according to the present embodiment, the pressure at the top of the tube nest 3 is lowered by adjusting the arrangement of the cooling tubes 1 forming the tube nest 3, thereby making the degree of vacuum of the condenser higher. Can improve the performance.

[0016]

As described above, according to the present invention, it is possible to provide a condenser in which pressure loss is reduced and performance is improved by allowing steam to smoothly flow into the tube nest.

[Brief description of drawings]

FIG. 1 is a front view and a side view of an axial flow exhaust condenser showing an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between steam temperature and cooling water temperature at each point in the condenser.

FIG. 3 is a diagram showing a vapor condensation amount at each point of a tube nest.

FIG. 4 is a comparison diagram of pressure distributions of the present embodiment and the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cooling pipe, 2 ... Extraction pipe, 3 ... Tube nest, 4 ... Container, 5 ... Steam inlet, 6 ... Drain, 7 ... Drain outlet, 8 ... Steam flow, 9 ... Flow path, 10 ... Folding water chamber, 11 ... Cooling water inlet side, 12 ... Cooling water outlet side, 13 ... Front side, 14 ... Back side,
15 ... Flow of cooling water.

Claims (5)

[Claims] 1. A pipe nest comprising a plurality of cooling pipes for condensing vapor flowing into a container from an inflow port, the pipe nest being provided at an inlet side and an outlet side of cooling water flowing through the cooling pipe. In a split two-fold flow condenser, the ratio of the tube nest widths of the cooling water inlet side and the outlet side substantially corresponds to the ratio of the vapor condensation amounts at the cooling water inlet side and the outlet side tube nests. A condenser characterized by arranging and arranging these tube nests so as to become one. 2. A pipe nest comprising a plurality of cooling pipes for condensing the steam that has flowed into the container from an inlet, and the pipe nests are provided on an inlet side and an outlet side of cooling water flowing through the cooling pipe. It is a two-fold flow condenser that is divided and is divided into a front side and a back side when viewed from the steam inlet, and the ratio of the cooling tubes of the tube nest divided into the front side and the back side is the above. A condenser characterized in that these tube nests are arranged and arranged so as to substantially correspond to the ratio of the amount of condensed vapor in the tube nests on the front side and the back side. 3. A tube nest having an inflow port for introducing steam into the container, a plurality of cooling pipes for condensing the steam inflowing from the inflow port, and an extraction pipe for extracting non-condensable gas mixed with the steam. An outlet for letting out a condensate condensed in the tube nest, the tube nest being divided into an inlet side and an outlet side of cooling water flowing in the cooling pipe, and the front side when viewed from the steam inlet. A two-fold flow condenser divided into an inner side and an inner side, wherein the extraction pipe is installed between the divided inlet side nest and outlet side nest, and cooling water at a steam inlet is provided. The ratio of the tube nest width on the inlet side and the outlet side is arranged and arranged so that the tube nest is configured so as to substantially correspond to the ratio of the condensation amounts of steam in the tube nests on the cooling water inlet side and the outlet side, and The ratio of the cooling tubes of the tube nest divided into the front side and the back side is such that the vapor condensation in the tube nests on the front side and the back side is A condenser characterized in that tube nests are arranged and arranged so as to approximately correspond to the reduction ratio. 4. The condenser according to claim 1, wherein the ratio of the tube nest widths of the cooling water inlet side and the outlet side is 1.7: 1.0. 5. The ratio of the cooling tubes of the tube nests on the front side and the back side is
6 to 7: 3 to 4;
The condenser described in 2.