JPS6044709A - Moisture separating heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a moisture separation heater for a steam turbine, and particularly to a BWR in which the generated steam becomes wet at the inlet of a low pressure turbine.
The present invention relates to a moisture separation heater suitable for use in steam generation equipment.

[Background of the invention]

For example, since the steam generated in a BWR steam generation facility is saturated steam, the humidity of the high-pressure turbine exhaust is 10 to 13%1, that is, it becomes wet at the inlet of the low-pressure turbine.

This moisture causes a decline in the performance of low-pressure turbines and blade erosion.

For this reason, a moisture separation heater is generally installed between the high-pressure turbine and the low-pressure turbine to remove moisture from the steam, heat it, and reheat the steam to increase the performance of the low-pressure turbine.

However, conventional moisture separation heaters separate heating steam tube bundles into two
Due to the stacked configuration, the tube bundle occupies most of the space of the entire heater.

Therefore, the overall size of the heater is estimated to be large, for example, in a 1300 MW class BWR using four heater shells with an outer diameter of 5 m, a total length of 40 m, and a total weight of 500 byrL. Assembly, transportation, and on-site installation are extremely disadvantageous in terms of work and cost.

[Purpose of the invention]

The purpose of the present invention is to improve the heat transfer performance, thereby making it possible to make the entire heater smaller and lighter in weight. An object of the present invention is to provide a separation heater.

[Summary of the invention]

In order to achieve this objective, the moisture separation heater of the present invention is constructed by constructing a heating steam tube bundle by overlapping special plates formed in a corrugated shape, and the grooves of the special plates are directed diagonally downward. Each groove of the special plate is provided with a fin that prevents heat exchange between the heated steam and water droplets that are separated from the heated steam and collects in the groove, and removes the water droplets along the groove lines. The present invention is characterized by having a structure in which moisture removal and heating are performed simultaneously, and the space occupied by the tube bundle is reduced.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 is an external front view of the moisture separating heater according to the present invention, Fig. 2 is a longitudinal sectional front view of Fig. 1, Fig. 3 is a sectional view taken along the - - - arrow in Fig. 2, and Fig. 4 is a sectional view taken along the 3 is an IV-IV arrow view, FIG. 5 is a perspective view showing a heated steam tube bundle, and FIG. 6 is an explanatory diagram showing the steam flow pattern and the behavior of water droplets and condensate in the tube bundle of FIG. 5. .

In FIGS. 1 and 2, the pressure vessel is formed of a cylindrical shell 1 and an end plate 2 that closes both ends of the shell 1. At the top of the shell 1 are inlets 3 and 4 for heated steam; A heated steam inlet 5 is provided, and a heated steam condensate outlet 6 and a drain discharge lower are provided at the bottom. Mirror plate 2
An inlet 3 for the steam to be heated is provided at the upper part. A moisture separator 8 for removing moisture from the heated steam introduced from the inlet 3 is installed in the lower part of the pressure vessel, and a drain plate 13 forming a drain chamber 12 in the lower part of the shell 1 is installed. is set up. Further, in the center of the pressure vessel, a tube bundle 9 is installed which circulates heated steam introduced from the inlet 5 to heat the heated steam exiting the moisture separator 8. 1O is a rectifying plate that rectifies the heated steam introduced from the inlet 3, and 11 is a partition plate.

The inlet 3 and outlet 4 of the heated steam, the inlet 5 of the heated steam
and condensate outlet 6, drain discharge lower, moisture separator 8,
The pipe 4J9, the rectifying plate 10, and the partition plate 11 are arranged symmetrically with respect to the inlet 3 of the steam to be heated, which is provided at the center of the upper part of the shell 1.

The arrow A indicates the flow of heated steam, and the arrowhead indicates the flow of heated steam.

As shown in FIG. 5, the tube bundle 9 is constructed by overlapping special plates 9A formed in a wave shape, and allows heated fluid to flow through each passage 14 along the grooves of the special plates 9A. is now possible. Further, the special plate (9A) in each row is supported by a support rod 15 so as not to bend due to the differential pressure (54 ata) between the heating side steam pressure (68 ata) and the heated side steam pressure (14 aja).

The above-mentioned special plate) 9A is manufactured by plastically working a flat plate into a trapezoidal wavy plate using a press machine.

The material for the special plate (9A) is ferritic stainless steel, which has excellent corrosion resistance.

Furthermore, in each groove of the special play 9A in the tube bundle 9, a fin 16 is provided along the groove line to partition the groove into two. The fins 16 are fixed to the special plate 9A by welding.

As shown in FIG. 3, the tube bundle 9 is arranged in two stages, upper and lower, in an inclined state. That is, there are two steam chambers 18A partitioned by a partition plate 17 in the center of the shell 1.
, 18B, a tube bundle 9-1 is formed between one steam chamber 18A and the inlet 5, and a tube bundle 9-1 is formed between the steam chamber 18A and the outlet 6.
A tube bundle 9-3 is placed between the other steam chamber 18B and the inlet 5, and a tube bundle 9-4 is placed between the steam chamber 18B and the outlet 6. In other words, each tube bundle is arranged so that the groove of the special plate 9A shown in Figure 5 faces diagonally downward, and the special plate 9A
The heated steam flowing between them flows perpendicularly to the grooves of the special jv-)9A.

In FIGS. 3 and 4, 19 is a rectifying plate that rectifies the heated steam introduced from the inlet 5, 2o is a tube plate of the tube bundle, and 21 is a special plate that separates the heated steam flowing between special plates of the tube bundle. This is a water droplet discharge groove that receives water droplets removed from the groove and guides it to the drain chamber 12.

Next, the operation of the present invention will be explained. Exhaust steam (humidity 10-13%) sent from a high-pressure turbine (not shown)
is introduced to the inlet 3 in FIGS. 1 and 2 as steam to be heated. The steam to be heated that has flowed into each population 3 is distributed to a uniform flow rate by the partition wall 11 and the rectifying plate 10, and the moisture separator 8
The moisture (water droplets) is separated here. The separated water droplets flow downward, are collected in the drain chamber 12 via the drain plate 13, and are then discharged to the outside from the drain discharge lower. Heated steam from which moisture has been separated (humidity 1~
2%) is the heating steam tube bundle 9-1.9-2 shown in Figure 3.
．． While flowing through the 9-3.9-4 section as shown by arrow A, it is heated by exchanging heat with the heated steam flowing through the passage of the tube bundle, flows out from the outlet 4, and flows toward the low-pressure turbine side. be guided.

On the other hand, the heated steam flows in from the inlet 5 shown in FIG. 2, and after being distributed to a uniform flow rate by the rectifying plate 19 shown in FIG.
It flows through each passage of the tube bundle 9-1.9-2, the steam chambers 18A and 18B, and each passage of the tube bundle 9-3.9-4 as shown by the arrows, and during this time it exchanges heat with the heated steam and condensed liquid. The condensate then flows out from the condensate outlet 6 and is guided to the feed water heater side.

In the process in which the steam to be heated is heated by the heating steam in each tube bundle, the flow of the steam to be heated is as shown in FIG. Become.

Therefore, the flow of the steam to be heated becomes a wavy flow as shown by arrow A in Fig. 6, and the moisture in the steam collides with the groove side surface 21 of special play 9A due to its inertia as shown by arrow A. Due to the action of gravity 2, the water droplets 24 are subjected to component forces N and F, gather in the groove 23 between the groove side surface 22 and the fin 16, and are pushed by the fin 16 into the groove 23' on the opposite side from the groove 23. movement is prevented. In the tube bundle 9, the grooves of the special plate 9A are arranged diagonally downward, so that the water droplets are drawn to the grooves 2 by their own surface tension.
2, it passes through the groove 23 and moves downward y.
flows down to The water droplets then fall from the tube plate at the lower end of the special plate 9A into the drain groove 21 shown in FIG.
The water is collected in the drain chamber 12 and discharged to the outside through the drain discharge lower.

On the other hand, since the heated steam flows in the passage 14 parallel to the grooves of the special plate 9A, the flow type is such that the pressure loss is small. The condensate 25 is condensed by exchanging heat with the heated steam.
As shown in Figure 6, due to the action of gravity 2, the component forces N and F
Then, it flows down while gathering at one corner of the passageway 14 in the N direction. At this time, the condensate 25 on the heating side and the water droplets 24 on the heated side in the groove 23 are adjacent to each other via the special play (9A), and since both flows are laminar, the heat transfer (9) is bad. On the other hand, the flow of steam is turbulent in both cases, and the flow is cross-flow through the special plate (9A), so heat transfer is good. In other words, the moisture in the steam to be heated has a small amount of heat taken away as latent heat of vaporization, and the moisture in the heated steam is in the form of water droplets in the groove portion 2.
Heat transfer performance is good because more is discharged.

Therefore, in the moisture separation heater according to the present invention, the moisture removal and heating of the steam to be heated can be performed simultaneously in the tube bundle section, that is, the heat transfer performance of the tube bundle section can be improved, so that the tube bundle section can be made smaller. I can do it.

Table 1 shows a comparison of the present invention and the conventional technology regarding heat transfer performance, and Table 2 shows the heat transfer area and length of the tube bundle per unit installed in a 1300 MW BWR.
The size of the shell and the degenerate lid of the heater are compared between the present invention and the conventional one.

(10) Table 1 Table 2 As can be seen from these tables, in the present invention, by improving heat transfer performance, the entire heater can be made smaller,
This makes it possible to reduce weight, facilitate factory assembly, transportation, and on-site installation, and reduce costs.

(11) [Effects of the Invention] As explained above, according to the present invention, the heat transfer performance can be improved by removing moisture from the steam to be heated and heating it at the same time. The weight can be reduced, making factory assembly, transportation, and on-site installation easier, while reducing costs.

[Brief explanation of drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is an external front view of a moisture separating heater according to the present invention, FIG. 2 is a longitudinal sectional front view of FIG. 1, and FIG. Fig. 4 is a cross-sectional view taken along arrows ■-■ in Fig. 2, Fig. 4 is a view taken along arrow M-IV in Fig. 3, Fig. 5 is a perspective view showing a heating steam tube bundle, and Fig. 6 is a sectional view of the tube bundle shown in Fig. 5. FIG. 2 is an explanatory diagram showing the vapor flow mode and the behavior of water droplets and condensed liquid. 9... Tube bundle, 9A... Special plate, 14... Passage, 16... Fin, 23... Groove. Agent Patent attorney Masami Akimoto (12) Figure 3 ° Unexamined Japanese Patent Publication No. 6O-44709 (5) 86 Kanmoku Gentaku''

Claims (1)

[Claims] 1. In a moisture separation heater for a steam turbine, the heating steam tube bundle is constructed by overlapping special plates formed in a corrugated shape, and the grooves of the special plates are arranged diagonally downward. Each groove of the special plate is provided with fins that prevent heat exchange between the heated steam and water droplets that are separated from the heated steam and collect in the groove, and remove the water droplets along the groove lines. What is claimed is: 1. A moisture separating heater, characterized in that it is configured to perform moisture removal and heating at the same time. 2. Moisture separation heating according to claim 1, characterized in that the flow of the heating steam is made to match the direction of the grooves of the special plate, and the flow of the steam to be heated is made perpendicular to the grooves of the special plate. vessel. 3. The moisture separating heater according to claim 1 or 2, wherein the special plate is made of ferritic stainless steel.