KR830003027Y1 - Shell and tube heat exchanger - Google Patents

Abstract

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Description

Shell and tube heat exchanger

1 is a longitudinal sectional view of a conventional tubular water heater.

2 is a cross-sectional view taken along line II-II of the feedwater heater of FIG.

Figure 3 is a longitudinal sectional view showing one embodiment of the feed water heater according to the present invention.

4 is a cross-sectional view taken along line IV-IV of FIG.

5 and 6 are top cross-sectional views showing another embodiment of the feed water heater according to the present invention.

The present invention relates to a tubular heat exchanger, and more particularly to a feed water heater for processing a large amount of steam and wet steam.

First, the structure of the conventional tubular water feed heater will be described with reference to FIGS. 1 and 2.

Conventional feedwater heaters are each fed with a turbine bleed (A) as a heating medium from the steam inlet 6 and the drain inlet 7 installed in the body 1, and from the high-pressure side feeder The drain B flows in and the high temperature pipe 15 formed on one side of the U-shaped heat pipe 8 and the low temperature pipe 16 symmetrically formed on the other side of the heat pipe. Distribute. The heat is supplied to the feed water flowing in the heat transfer pipe 8, but the steam condenses and becomes a drain, and as shown in the bottom 11 of the fuselage 1, is cooled in the drain coulter 10 and is fed to the feed water heater. To be discharged from the And 4a is a water chamber at the water inlet side for supplying water to the low temperature pipe 16, 4b is a water chamber at the water outlet side for drawing hot water from the hot water pipe 15, and 2 and 3 are each water supply. Inlet and outlet, 5 is a pipe plate, 9 is a pipe support plate, 12 is a bent tube disposed between the hot pipe 15 and the cold pipe 16 to discharge non-condensable gas.

In this water supply heater, since the heat load from the low temperature pipe 16 is so large that the high temperature pipe 15 cannot be compared, the steam completely loses heat and the U-shaped heat pipe ( 8) A refining zone 17 (hereinafter, referred to as a stagnant zone) of non-condensable steam is generated, which does not undergo heat exchange even with the feed water flowing therein.

Non-condensable gas containing ammonia gas stays in the stagnant region 17 to corrode the heat transfer tube 8. For this reason, conventionally, a rectifying plate 18 or a pipe settlement section 19 is provided in the pipes 15 and 16, whereby heated steam is introduced into the pipe and the stagnant area 17 The non-condensing gas of the s) is moved to the position of the vent pipe 12 to reduce the plateau area 17 and to be collected in a small place. However, in case of feed water heaters used in power plants of 600MW or more, the number of pipes is used more than thousands, so the pipeline is very large. For this reason, a new stagnant region 20b is formed in the deep part of the conduit near the center of the low temperature pipe 16. The stagnant region 20a is also formed at the rear side of the rectifying plate 18 of the high temperature pipe 15. In other words, the central stagnant region 20b of the cold conduit 16 is located at the bottom of the upper surface of the cold conduit 16 due to the drain surface 11 accumulated at the bottom of the flow moving body 1 of steam flowing downward through the outside of the conduit 16. While the flow cannot be diverted well in the direction of), the congestion is deep and the stagnant region 20b is generated. In addition, the stagnant region 20a generated on the back side of the rectifying plate 18 of the hot pipe 15 is different from the point where the rectifying plate 18 accurately shields the steam flowing from above and the point where the pipe is deep. The stagnant region 20a is generated on the back side of the rectifying plate 18 by the synergistic action. Therefore, in the feed water heater using aluminum brass tubes as the heat transfer tubes, ammonia gas may be retained in the stagnant region, which may cause corrosion of the heat transfer tubes due to the attachment of ammonia.

It is an object of the present invention to provide a multi-tube heat exchanger in which a stagnant region of non-condensable gas does not occur in a conduit of a heat transfer tube even in a large heat exchanger.

Next, a water feed heater, which is an embodiment of the present invention, will be described with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, since the schematic structure of the feed water heater shown in FIG. 1 and FIG. 2 is the same, only different parts are demonstrated.

23 is a heat pipe payment section, which is a flow path for introducing a heating medium formed from the outer periphery of the pipe to the inside of the pipe in each of the hot pipe 15 and the cold pipe 16 composed of a plurality of heat pipes 8. ) Is formed along the excretion direction of the heat transfer tube 8. And inside this payment part 23, two rectifier plates 24a, 25a, 24b, 25b, 24c, 25c, 24d, and 25d are parallel and mutually spaced apart, respectively, and the longitudinal direction of the fuselage 1 is carried out. The barracks are provided along the discharge direction of the phosphorus heat transfer tube 8 so as to form the vapor flow paths 22a to d, respectively, between the rectifying plates 24a to d and 25a to d. When the steam flow paths 22a to d are formed in this way, the steam, which is a heating medium introduced into the flow paths 22a to d, is separated between the rectifying plates 24a to d and 25a to d by the pressure difference between the outer peripheral side of the pipe and the inside. Rather than deflecting the vapor flow passages 22a to d, they flow to the ends of the flow passages 22a to d and reach the inside of the undersized portions 15 and 16 directly.

Therefore, the pressure of the steam reaching the inner end of the steam flow passage 22 can be introduced as compared with the installation of one rectifier plate only in the conventional heat transfer tube settlement unit or the insulated tube settlement unit.

As a result, due to the pressure difference between the inner end of the steam flow passage 22 and the vicinity of the vent pipe 12 (the lowest pressure region), the stagnant regions at 20a and 20b are moved to the vent pipe 12. As a result, generation of the stagnant region can be prevented, and the non-condensable gas can be efficiently extracted from the vent pipe 12 to the outside.

As such, when the stagnant zone in the pipe is removed, the heat exchange area increases as much as the stagnant zone is removed, thereby improving the performance as a heat exchanger. In addition, when the heat transfer tube is eroded by ammonia attachment, such as an aluminum brass tube, the formation of the stagnant region itself is prevented, so that the concern about erosion of the heat transfer tube by the ammonia remaining in the stagnant region can be eliminated. In this embodiment, the widths of the rectifying plates 24 and 25 are changed to stagger the positions of the inner ends of the rectifying plates, thereby expanding the direction of steam flow and returning the steam flow in a desired direction. Can be.

That is, in the hot pipe 15, the length of the width of the rectifying plate 24 near the center of the pipe is formed long, and the length of the width of the rectifying plate 25 is short. A portion of the portion is allowed to flow to the back side of the rectifying plate 25 to prevent the conventional retention area 20a from occurring in this portion. In the low temperature pipe 16, the width of the rectifying plate 25 near the center of the pipe is shorter than that of the rectifying plate 24 so that a part of the air introduced into the steam channel 22 flows near the center of the low temperature pipe. This prevents the conventional retention area 20b from occurring in the portion.

Figure 5 shows another embodiment of the water supply heater of the present invention, the structure and the different parts of the water heater of Figure 4 forms a vertical direction of the steam flow path 22 while the hot pipe 15 and low temperature Both of the tubes 16 were formed so that the length of the width of the rectifying plate 24 on the center of the tube was longer than that of the rectifying plate 25. This prevents the occurrence of the stagnant region 20c in the station.

FIG. 6 shows another embodiment of the present invention, and the same reference numerals as in FIGS. 26 is an impact preventing plate made of a porous plate which is also provided in a conventional water heater, and both sides thereof are joined to an upper portion of each of the rectifying plates 24 and 24 of the two vapor passages 22. The upper ends of the other rectifying plates 25 and 25 are bent inward to form a drain short 25a. In addition, a vapor guide plate 27 is attached to the top of the impact preventing plate 26.

According to the configuration of this embodiment, the drain B in the wet steam A coming from the steam inlet 6 is jumped by the impact preventing plate 26, but the drain C is to jump and reach the inner surface of the body 1. ) Collides with the drain short circuit 25a formed at the upper end of the rectifying plate 25 and flows down into the rectifying plates 24 and 25. Therefore, it is possible to separate the steam flow and the drain flow outside the pipe.

As a result, in addition to the removal effect of the stagnant region, the effect of reducing moisture in the steam is exerted, and the influence on the inner surface of the body 1 by the wet steam can be reduced.

In the above embodiment, an example in which a steam flow path is formed by using two rectifying plates in a pipe is described. Instead of the rectifying plate, a cylinder or the like which blocks the inner part of the body in the longitudinal direction may be used. In addition, the present invention can be applied to a tubular heat exchanger of a fluid regardless of liquid or gas. As described above, in the present invention, a fluid flow path extending from the outer periphery of the pipe to the inside of the pipe is provided, and a plate member is disposed in the flow path to divide the flow path so that a high pressure fluid can be introduced to the end of the fluid path. Can be. Therefore, the fluid can be sufficiently introduced into the tube to remove the stagnant region of the non-condensable gas from the tube, thereby improving the efficiency of heat exchange. As an additional effect, the extraction amount of non-condensable gas from the vent pipe can also be reduced, thereby improving the thermal efficiency.

Claims (1)

Inlet 6, 7 of the heating body 1 and the heating medium provided in the body 1 and a plurality of U-shaped heat pipes 8 disposed in the body 1 for circulating the heat exchanged with the heating medium. Inlet water chamber which is connected to the pipes 15 and 16 constituted by the end portion of the body 1 and supplies the heat exchanged heat to the U-shaped one side heat transfer pipe 8 constituting the low temperature pipe 16. 4a and the hot water pipe in the fuselage 1 and the outlet water chamber 4b which introduce the heat exchanged fluid from the U-shaped heat transfer pipe 8 which is connected to the fuselage 1 and constitutes the hot pipe 15. A multi-tubular heat exchanger having a discharge pipe (12) located between the (15) and the low temperature pipe (16) and discharging non-condensing gas in the body (1) disposed along the heat pipe (8) constituting the pipe. Pipe the heating medium flowing from the inlets 6 and 7 provided in the fuselage 1 in at least one of the hot pipe 15 and the cold pipe 16. Flow paths 22a, 22b, 22c, 22d and 22e, 22f, 22g, 22h, which are introduced into the inside of the pipe from the outer periphery, are formed along the discharge direction of the heat transfer pipe 8, and the flow paths 22a to 22h are formed. A plurality of plate members (24a, 25a; 24b, 25b; 24c, 25c; 24d, 25d), (24e, 25e; 24f, 25f; 24g, 25g; 24h, 25h) that divides the discharge direction of the heat transfer pipe (8) A multi-tube heat exchanger, characterized in that installed according to.