JPS631515B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a condenser, and particularly to an arrangement of cooling pipe groups in an air cooling section of a steam turbine condenser.

Steam turbine condensers are usually provided with a so-called air cooling section. The reason for installing this air cooling section is as follows. There is a negative pressure state from the low pressure stage of the steam turbine to the inside of the condenser, and air inflow from the communicating steam pipe flanges between the two is unavoidable. This mixed air is accumulated in the condenser together with ammonia gas and other gas generated when hydrazine, which is injected into the water supply of the high-pressure feedwater heater to prevent corrosion of steel pipes, is decomposed in the boiler. These non-condensable gases are extracted to the outside of the vessel by an air extractor to maintain a predetermined degree of condensate vacuum.

Generally, these non-condensable gases are accompanied by steam, and an air cooling section is provided in order to recondense the entrained steam, reduce the gas volume, and reduce the load on the air extractor.

FIGS. 1 to 3 show examples of the arrangement of conventional condensers and air cooling units. Here, the turbine steam 14 is transferred to a cooling chamber 15 in which a tube nest 6, which is a collection of cooling tubes 1, is arranged.
Most of the steam flows into the condenser from the surroundings and is condensed by the cooling water flowing through the condenser cooling pipe 1. Also,
Entrained air, ammonia gas and some steam flow into the non-condensable gas bleed pipe 3 through the holes 10 and are guided to the air cooling section 7. Here, a part of the vapor is condensed, and the non-condensable gases are further cooled and discharged through the air extraction pipe 8 by the air extractor 9.

This air cooling section 7 is surrounded by a partition plate 5 on its top and side surfaces to prevent uncondensed steam from the surrounding tube nest 6 from flowing into the air cooling section 7, and to prevent uncondensed steam from flowing into the tube nest 6 between the support plates 2 holding the cooling tube 1. In the nest 6, a partition plate 11 shown in FIG. 2 is provided to prevent uncondensed steam from flowing directly into the uncondensed gas bleed pipe 3. 4 is a tube plate, 12 and 13 are water chambers, 16 is a casing, 17
18 is the central cavity of the tube nest, and 18 is the condensate. This method of arranging the air cooling section has the following drawbacks.

(A) Extra space is required to provide the partition plates 5 and 11 within the tube nest, and there are also manufacturing difficulties.

(b) Part of the tube nest is partitioned with a partition plate, which causes uneven steam flow, which promotes uneven steam velocity and increases pressure loss.

An object of the present invention is to provide a condenser with excellent performance that solves the above-mentioned drawbacks.

An embodiment of the condenser according to the present invention will be described below with reference to the attached FIGS. 4 and 5.

In FIGS. 4 and 5 (FIG. 5 is taken from the V-V arrow in FIG. 4), the condenser includes a cooling chamber 15, a water chamber 12,
13, the cooling chamber 15 has a tube nest 6 in which the cooling tubes 1 are densely arranged in the center and sparsely arranged around the periphery, and is held by the tube plate 4 and the tube support plate 2, and the turbine exhaust gas guided to the cooling chamber 15. Steam 14 is guided into the center of the tube nest 6. A non-condensable gas bleed pipe 3 having a hole 10 on its outer surface is installed in the central cavity 17 of the tube nest. In the space 19 partitioned by the tube plate 4 and the tube support plate 2 on the cooling water inlet side, there is no non-condensable gas bleed pipe 3, and the shape is similar to that of the tube nest central cavity 17 at right angles to the longitudinal direction of the tubes. In addition, a somewhat large deflecting plate 20 is arranged.

The operation of the condenser having the above structure will be explained below.

Steam 14 flows from around the tube bundle 6 with minimal pressure loss. Most of this steam exchanges heat with water in the cooling pipes 1 constituting the tube nest 6 and condenses. In addition, air, ammonia gas, etc. mixed in the steam are guided to the non-condensable gas bleed pipe 3 through the hole 10 along with some unevaporated steam. And this deflector plate 2
0, it passes again between the cooling pipes 1 as indicated by the arrow 21, and the accompanying steam is condensed into condensate 18, and non-condensable gas such as air is discharged through the air extraction pipe 8 in the air extractor 9.

As described above, according to the present invention, the air cooling section can be configured without the need to provide the partition plates 5 and 11 between the cooling pipes, and without taking up any special space. Therefore, the flow of steam is good, pressure loss is small, and excellent effects such as prevention of pipe corrosion due to ammonia retention are achieved.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing the structure of a conventional condenser.
2 is a sectional view in the - direction of FIG. 1, FIG. 3 is a sectional view in the - direction of FIG. 1, FIG. 4 is a longitudinal sectional view of the condenser according to the present invention, and FIG. - It is a sectional view in the V direction. 6: tube nest, 3: non-condensable gas bleed pipe, 4: tube plate,
20: Deflection board.

Claims (1)

[Claims] 1 In a condenser equipped with a non-condensable gas bleed pipe in a pipe nest formed by a plurality of cooling pipe groups through which cooling water flows, in order to cool and condense the steam led into the condenser, the cooling water is A condenser characterized in that a deflecting plate similar in shape to the cavity in the tube nest and slightly larger in size is provided between an inlet side tube plate and a tube support plate opposing the same.