JPS59185904A - Steam separating reheater and method of controlling said steam separating reheater - 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 brackish water separation reheater suitable for use in nuclear power plants and the like, and a method for controlling the same.

[Background of the invention]

Generally, steam generated from a boiling water type or pressurized water type light water reactor and supplied to a nuclear turbine plant is saturated steam having a lower pressure than steam generated from a boiler applied to a conventional thermal power plant.

In the process of expanding this saturated steam within the turbine and converting it into mechanical energy, the moisture content of the saturated steam increases rapidly. If saturated steam with high moisture content is directly introduced into the subsequent turbine stage, it will cause a decrease in turbine internal efficiency and erosion, resulting in significant problems in terms of both turbine performance and reliability. Therefore, in the prior art, as shown in FIG. 1, a brackish water separator 103,
A brackish water separation reheater 106 composed of a first reheater 104 and a second reheater 105 is provided to remove moisture from the saturated steam flowing toward the low-pressure turbine 102 and reheat it. It is being implemented.

In the heat exchanger tube 108 of the first reheater 104, heated steam extracted from the middle of the high-pressure turbine 101 flows through the flow control valve 10.
7 and the heat exchanger tubes 10 of the second reheater 105
Heating steam branched from main steam from the nuclear reactor is introduced into the reactor 9 via a flow control valve 111 . Also, 1st. Second
The heat exchanger tubes 108 and 109 of the reheat tubes 104 and 105 are connected to the reserve tank 110 and 112, and the heat exchanger tubes 108 and 10
Discharge the scavenging steam and condensate in 9. Reserve tank 1
10, 112, brackish water separator 103 and low pressure turbine 1
The drain generated at 02 is sent to the feed water heater 113. In addition, the scavenging steam discharged from the reserve tanks 110 and 112 is passed through flow control valves 114 and 115 to the feed water heater 113.
sent to.

Exhaust steam from the high pressure turbine 101 is transferred to a brackish water separator 103
After separating the input moisture, it is introduced into the first reheater 104 and heated by the heating steam flowing inside the heat transfer tube 108.
It is further guided into the second reheater 105, heated by the heated steam in the heat transfer tube 109, changed to a superheated steam state, and sent to the low pressure turbine 102. However, on the other hand, the heat exchanger tube 108
．． In 109 the heated steam condenses. If this condensation is excessive, there will be a problem that the condensation will be completely condensed within the outlet ends of the heat exchanger tubes 108, 109. In order to solve this problem, the conventional technology also uses a heat exchanger tube 108 as shown in FIG.
, 109, but it was considered to be insufficient.

For this reason, a control method as introduced in Japanese Patent Application No. 56-99845 was adopted. That is, as shown in Figure 2, the first
The temperature of the heated steam that has passed through the reheater 104 (the same applies to the second reheater 105), the amount of scavenging steam and the amount of drain from the reserve tank 110 are detected, and the flow rate control valves 109 and 114 are controlled based on this. In this way, unstable flow is prevented from occurring within the heat exchanger tube 108. However, this method does not detect the individual flow state of the heat exchanger tubes 109 formed from a large number of tubes, but is insufficient because it is grasped as a cross), and cannot control all of the heat exchanger tubes 108 to a stable state. First, there was a drawback that the reliability and thermal efficiency of the plant could not be improved.

Next, the prior art will be explained in more detail.

FIG. 3 shows the overall configuration of the brackish water separation and reheater 106.

Brackish water separator 103, first and second reheaters 104.1
05 is inserted into an elongated closed hollow cylindrical outer shell 17. The illustrated brackish water separation reheater 106 has a large capacity, so the first reheater 104a has the same shape as the central part.
, 104b and second reheaters 105a, 105b are housed facing each other. Steam inlet pipes 5a, 5b are provided on the outer wall of the outer shell 17 for introducing exhaust steam 6a, 6b, 6c, 6d from the high-pressure turbine 101 into the interior.

5C, 5d and superheated feed steam 8a, 8b.

Steam outlet pipes 7a, 7 that send 8C to the low pressure turbine 102 side
b and 7c are provided, respectively.

As shown in FIG. 4, the brackish water separator 103 has an outer shell 17
arranged on the lower side of the
A brackish water separator 103a is arranged in a V-shape in a room divided by 9a and 19b.

103b. The first reheater 104 and the second reheater 105 are provided above the brackish water separator 103, and are connected to the partition walls 20a and 20b connected to the partition walls 19a and 19b.
It is supported and stored in the chamber formed between them. Further, the first and second reheaters 104 and 105 are formed from a large number of heat transfer tube groups 108 and 109, as will be explained later. Further, on the outer wall side of the outer shell 17, there is a drain pipe 15 for discharging the drains 16a and 16b excluded by the brackish water separator 103.
a and 15b are provided. Further, headers 9.10 are formed on the inlet sides of the first and second reheaters 104, 105, and a heating steam pipe 11.13 and a drain discharge pipe 12.14 are connected to the headers 9, 10. There is. The heating steam pipe 11 is connected to a high pressure turbine 101, and the heating steam pipe 13 is connected to a main steam pipe of a nuclear reactor (not shown).

FIG. 5 shows header 9 (header 10 is also the same).

The header 9 has a closed space surrounded by an outer partition wall 18, a tube plate 22, and side walls (not shown) installed at both ends of these, and a heating steam chamber 24 and a drain chamber 25 using an intermediate partition plate 21.
A heating steam pipe 11 is provided to introduce heating steam 26 into the heating steam chamber 24, and a drain 29 is provided in the drain chamber.
A drain discharge pipe 121r from which water is discharged is provided.

On the other hand, the heat exchanger tube group 108 includes a large number of long V-shaped heat exchanger tubes 2.
3, and the inlet portion 2 of the heat exchanger tube 23 on the outermost edge side thereof.
3a and the outlet portion 23a' are held by the tube plate 22 and communicated with the heating steam chamber 24 and the drain chamber 25. Similarly, the innermost heat exchanger tube 23 and the inlet portions 23d, 23b, 23c and outlet portion 23d' of the heat exchanger tube 23 located in the middle thereof.

23b' and 23C' also have a heating steam chamber 24 and a drain chamber 25.
are connected to each other.

The heated steam 26 from the high-pressure turbine 101 introduced into the heated steam chamber 24 from the heated steam pipe 11 is heated steam 27a, 27b, and 27C as shown by the arrows.

The inlet portion 23a of each heat transfer tube 23 is divided into 27d.
, 23b, 23c, and 23d, and go around the pipe to exit portions 23a'', 23b', 23c'.

From 23d', drain flows 28a and 28b as shown by the arrows.

It is discharged into the drain chamber 25 such as 28c and 28d, and is discharged as a drain 29 from the drain discharge pipe 12. As described above, the steam 30 from the brackish water separator 103 comes into contact with the outer peripheral side of the heat transfer tube 23, exchanges heat with the heated steam 27a, etc. in the heat transfer tube 23, and becomes superheated steam 31. Sent to the 105 side. On the other hand, the drain flow 283 and the like are generated within the heat exchanger tube 23 as described above.

As described above, the heated steam 27a and the like in the heat exchanger tubes 23 are condensed through heat exchange, but if the heat load is unbalanced or the amount of heated steam is not appropriate, excessive condensation will occur in the heat exchanger tubes 23, which have a large heat load. For this reason, the heated steam 278 and the like are completely condensed before reaching the outlet portion 233' of the heat exchanger tube 23, and a pool of supercooled condensate is generated, which causes the temperature of the heat exchanger tube 23 to become uneven.
Local thermal stress and thermal deformation are induced. Also, the transmission pipe 23
The two-phase flow of steam and condensate flowing inside does not become a laminar flow,
Extremely unstable flow conditions such as wavy flow, flood flow, and slug flow are formed, and problems such as water hammer occur, resulting in problems that impair the safety and reliability of the heat exchanger tubes.

Therefore, as shown in FIG.
an orifice 32b at the end of the outlet section 23a', etc.
, 32c, 32d, 32b'.

32c' and 32d' have been proposed, and methods have been proposed in which steam is added to scavenge the heat exchanger tubes 23. However, these measures do not completely solve the above-mentioned problems, and in particular, the means for inserting the orifice 32b etc. cannot cope with all operating conditions and load changes, and in practice, there are a huge number of It becomes extremely difficult to design an orifice to optimize the flow state of the heat exchanger tube 23. or,
Merely adding scavenging steam has the disadvantage of wasting a significant amount of heating steam, thereby reducing the thermal efficiency of the turbine plant.

Therefore, in the prior art, a solution has already been proposed in Japanese Patent Application No. 56-99485. This method is schematically illustrated in FIG.
05 is the same) is detected by a temperature detector 116, and the detected temperature is inputted to a comparator 117 by Δ. A set value of a temperature setting device 119 that calculates a desired temperature setting value is inputted to the comparator 117 from a turbine load change rate calculator 118, and the two are compared. The signal of this comparison value is the opening degree setting means 12.
0 variable temperature calculator 121, variable flow rate calculator 122, and variable valve opening calculator 123, and the flow rate control valve 10
9 to adjust the temperature of the superheated steam passing through the first reheater 104 to an appropriate temperature.

On the other hand, the amount of scavenging steam discharged from the heat transfer tube group 108 to the reserve tank 110 is detected by the flow rate detector 124, and the amount of drain is detected by the flow rate detector 125, and each detection signal is sent to the flow rate calculator 129. Scavenging steam amount calculator 1
26, is input to the drain amount calculator 127. These two calculated values are input to the flow pattern determiner 128, and the flow state (flow pattern) of the two-phase flow is determined. When it is determined that this flow state is in a region exhibiting unstable flow phenomena such as the above-mentioned wavy flow, allotment flow, and slab flow, the opening degree of the flow rate control valve 114 is controlled and adjusted to shift to an appropriate state. do.

Although the above control method has some effects, the temperature of the superheated steam passing through the first reheater 104 and the temperature of the reserve tank 1
The scavenging steam amount and drain amount from 10 are detected as a cross, and the heating steam amount,
Since the amount of scavenging steam is adjusted, there is a drawback that it is difficult to determine the state of two-phase flow in each of the heat exchanger tubes 23 formed from a large number of tubes. In particular, as described above, the largest heat load is applied to the outermost heat transfer tubes 23, and the amount of condensed liquid is also the largest. On the other hand, the amount of condensed liquid is the smallest on the innermost edge side. As described above, since the state of the two-phase flow changes depending on the arrangement position of the heat exchanger tubes 23, it is not possible to optimize all of these by the above method.

[Purpose of the invention]

The present invention was devised to solve the above-mentioned drawbacks and inconveniences, and its purpose is to prevent overcooling inside all heat exchanger tubes, maintain a stable fluid state, and improve the safety of heat exchanger tubes. An object of the present invention is to provide a brackish water separation and reheater that improves reliability and improves the thermal efficiency of a plant, and a method for controlling the same.

[Summary of the invention]

In order to achieve all of the above objects, the present invention divides a sealed space formed by a tube sheet holding the inlet and outlet parts of a large number of U-shaped heat exchanger tubes, an outer partition wall, and a side wall with an intermediate partition plate, Each of the heating steam chamber and drain chamber of the header of the reheat pipe forming the heating steam chamber and the drain chamber is further divided into a plurality of stages. A second heating steam chamber and a drain chamber are formed, corresponding to the first and second heating steam chambers and drain chambers. The heat exchanger tube is connected between the second heating steam chamber and the drain chamber, and the first heat exchanger tube is connected between the second heating steam chamber and the drain chamber. Brackish water separation and reheating system in which a heating steam pipe that introduces heating steam from a high-pressure turbine or a nuclear reactor and a scavenging steam pipe and a drain pipe that connect to the above-mentioned reserve tank are connected to a second heating steam room and a drain room, respectively. In addition, a flow control valve is interposed in the line path of the heating steam and the path through which the scavenging steam discharged from the drain chamber of the header flows, and Detects the temperature difference between the steam inlet and outlet and calculates the temperature rise value within the heat exchanger tube. This detected value is compared with a set value to control the flow rate control valve of the heating steam line, and the flow rate of scavenging steam and drain from each of the drain chambers is detected, and this detection signal is used to control the flow rate of each of the above-mentioned transmissions. The entire flow pattern of the two-phase flow in the heater is determined, and the flow control valves in the scavenging steam line and the heating steam line are controlled based on this, and the flow state of the two-phase flow is stabilized for each heat transfer device. The present invention is characterized by a method of controlling a brackish water separation reheater in which the

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

First, an outline of an embodiment of the brackish water separation and reheater will be explained.

As shown in FIG. 7, the header 9 of the first reheater 103 is
A heating steam chamber and a drain chamber formed by dividing a sealed space surrounded by an outer partition wall 18, a tube plate 22, and side walls 58 and 59 shown in FIG. 8 by an intermediate partition plate 21 are further divided into a plurality of stages. It is formed by a heating steam chamber 50, a first drain chamber 57, and the like.

Between the first heating steam chamber 50 and the first drain chamber 57, there is an inlet portion 23a and an outlet portion 33a' of the heat transfer tube 23 on the outermost edge side.
and a first scavenging steam pipe 48 and a first drain pipe 49 that send scavenging steam and drain to the first heating steam pipe 38 into which heated steam from the high pressure turbine 101 is introduced, and the reserve tank 110. Connected. Similarly, 2nd and 3rd. The fourth heating steam chamber 51, 52.53 and the second. Third. The fourth drain chamber 56, 55.54 also has a second drain chamber. Third. The fourth heating steam pipe 39, 40° 41 and the second. Third. The fourth scavenging steam pipe 46°44.42 is connected to drain pipes 47, 45.43, respectively.

Next, this embodiment will be explained in more detail.

As shown in FIGS. 7 and 8, the closed space of the header 9 includes the outer partition wall 18, the tube plate 22, and the side walls 58, 59.
The closed space is divided into a heating steam chamber and a drain chamber by an intermediate partition plate 21 which is disposed astride the space and substantially in the center of the sealed space. The heating steam chamber is further divided into a first heating steam chamber 5o by horizontal partition plates 32.33.34 arranged in parallel at appropriate intervals.
It is divided into a second heated steam chamber 51, a third heated steam chamber 52, and a fourth heated steam chamber 53. Also, the drain chamber has horizontal partition plates 37°36.35 which are arranged in parallel at appropriate intervals.
The first drain chamber 57, the second drain chamber 56, and the third
It is divided into a drain chamber 55 and a fourth drain chamber 54. Each of the first to fourth heating steam chambers 50, 51, 52.53 has first to fourth heating steam pipes 38, which introduce heating steam from the high-pressure turbine 101 (not shown).
39°40.41 are connected. Also, the first to fourth
Each of the drain chambers 57, 56, 55.54 has first to fourth scavenging steam pipes 48.46, 44.42 for discharging scavenging steam and drain from the drain chamber to the reserve tank 110 (not shown) and a fourth scavenging steam pipe 48.46, 44.42. First to fourth drain pipes 49, 47, 45° 43 are connected.

On the other hand, the tube plate 22 includes an inlet portion 23a of the heat transfer tube 23.

23b, 23c, 23d and outlet portion 23'a'.

23b', 23C', and 23d' are fixed, and the inlet part 23a and outlet part 238' of the heat exchanger tube 230 on the outermost edge side communicate with the first heating steam chamber 50 and the first drain chamber 57. In addition, the inlet portion 23d and outlet portion 23d' of the heat exchanger tube 23 on the innermost edge side are connected to the fourth heating steam chamber 53 and the fourth drain chamber 5.
Connects to 4.

Inlet part 2 of heat exchanger tube 23 located between the outermost edge side and the innermost edge side
3b, 23c and the outlet portions 23b', 23e' are the second. The third heating steam chamber 51.52 and the second. They communicate with third drain chambers 56 and 55, respectively.

Next, the operation of this embodiment will be explained.

Heating steam (including scavenging steam) sent from the high-pressure turbine 101 is passed through the first to fourth heating steam pipes 38, 39, 4.
0.41 to the first to fourth heating steam chambers 5 as described above.
0, 51, 52, 53), the inlet part 23 of the heat exchanger tube 23
a, 23b, 23c.

23d into each heat transfer tube 23.

A high pressure turbine 101 is installed on the outer peripheral side of each heat transfer tube 23.
The steam 30 sent from the above through the brackish water separator 103 contacts, exchanges heat with the heated steam in the heat transfer tube 23, is superheated, becomes superheated steam 31, and is sent to the second reheater 105 (not shown). . . On the other hand, the heated steam inside the heat exchanger tube 23 that has absorbed the amount of heat is condensed, and the first to fourth drain chambers 57, 56
, 55° 54 to exhaust scavenging steam and condensate. This scavenging steam and drain are connected to the first to fourth scavenging steam pipes 48°46
．． 44.42 and the first to fourth drain pipes 49.47,
45.43 and is discharged to the reserve tank 110 side.

In this embodiment, first to fourth heating steam chambers and drain chambers are formed, but of course the number is not limited to this number. or,
Although one heating steam pipe, one scavenging steam pipe, and one drain pipe are connected to each heating steam chamber and drain chamber, it is of course possible to provide a plurality of pipes. Moreover, the arrangement position is not limited to that shown in the drawings.

9 and 10 show another embodiment of the present invention relating to a brackish water separation and reheater.

In this embodiment, the heating steam chamber and the drain chamber are partitioned by arc-shaped partition plates 32' and the like arranged concentrically in place of the horizontal partition plate 32 and the like of the above embodiment. That is, the heating steam chamber divided by the intermediate partition plate 21 is divided into arc-shaped partition plates 32' and 3 arranged concentrically at appropriate intervals.
3', 34', a first heating steam chamber 50', a second heating steam chamber 51', a third heating steam chamber 52', and a fourth heating steam chamber 50'.
The heating steam chamber 53' is divided into two heating steam chambers 53'. Similarly, the drain chambers are divided into a first drain chamber 57', a second drain chamber 56', a third drain chamber 55', and a fourth drain chamber by arc-shaped partition plates 35', 3.6', and 37'. It is divided into 54'. In addition, as in the above embodiment, as shown in FIG.
, 51', 52'.

first to fourth heating steam pipes 38' communicating with 53';
, 39', 40', and 41' are connected in communication, and the first
4th drain chamber 57', 56'.

55' and 54' have first to fourth scavenging steam pipes 48.
', 46', 44', 42' and first to fourth drain pipes 49', 47', 45', 43' are connected in communication with each other.

The functions and effects of this embodiment are similar to those of the above-mentioned embodiments, but since the arc-shaped partition plate 32' and the like are used, it has excellent pressure resistance, and is advantageous when the pressure loss of each partitioned space is different.

Next, a preferred embodiment for carrying out the invention relating to a method of controlling a brackish water separation and reheater will be described based on the drawings.

First, an outline of this embodiment will be explained with reference to FIG. 14.

Heating steam 90a from the high-pressure turbine 101 (not shown) is supplied to the first to fourth heating steam chambers 50 of the header 9,
90b, 90c, and 90d are introduced into a heating steam system path, and flow control valves 91a, 91a, and 90d are installed in the system, respectively.
91b, 91c, and 91d are interposed. Further, scavenging steam 62 and drain 61 are sent to the reserve tank 110 from the first to fourth drains, the first chamber 57, and the like. A scavenging steam pipe 66 and a drain pipe 67 are connected to the reserve tank 110, and flow control valves 68 and 70 are interposed in the pipe system.

On the other hand, each heat exchanger tube 23 in the first reheater 104 (the same applies to the second reheater 105) has a temperature increase value of the steam to be heated near the inlet section 23a, etc. and outlet section 23a', etc. Temperature difference detectors 63, 64, etc. that measure ΔTs and ΔT1 are engaged. This detected value is input to the temperature rise detector 72 to obtain a temperature rise value, and this value is input to the comparator 73. On the other hand, a desired temperature rise set value determined by the turbine load, etc. is inputted from the temperature rise setter 74 to the comparator 73. The control signal 83 is determined by the difference between the two by the comparator 73.
is sent to the flow rate control valve 912 etc., and the flow rate of the heated steam 90a etc. is controlled and optimized.

On the other hand, flow rate detectors 69 and 71 are engaged with the scavenging steam pipe 66 and the drain pipe 67 to measure the flow rate flowing through these pipes. These detected values are input to a scavenging steam amount calculator 75 and a condensed liquid amount calculator 76, and based on these calculated values, a scavenging rate calculator 77 determines the scavenging rate. With this scavenging rate, p
, the flow state of the two-phase flow in each heat transfer tube 23 is determined by the flow pattern determiner 78, and it is evaluated whether the flow is unstable or not.

If the flow is in an unstable flow region, the scavenging rate is corrected by the scavenging rate corrector 79, and the control signal 86 is sent to the flow rate control valve 68 which controls the amount of scavenging steam to control the flow rate. . When controlling the scavenging flow rate, the flow rate of the heating steam 90a etc. must also be controlled at the same time, so the scavenging rate corrector 79
and a control signal 84.8 from the flow pattern determiner 78.
5 is sent to the flow rate control valve 91avf of the heated steam 90a, etc.
control.

By the above control method, the two-phase flow is stabilized for each heat exchanger tube 23.

Next, this embodiment will be explained in more detail.

In FIG. 11, the horizontal axis shows the distance from the heat exchanger tube 23 tube bundle population ■ (steam 30 side in FIG. 14) to the tube bundle outlet O (superheated steam 31 side), and the vertical axis shows the heated steam ( The figure shows the temperature rise value ΔT of the steam (steam from the brackish water separation 103). The temperature rise value ΔT, 1 of the portion near the outlet portion 23a′ of the heat transfer tube 23 on the side shown in the figure is the largest, and the temperature rise value ΔT8 of the portion near the inlet portion 23a of the heat transfer tube 23 on the outermost edge side, which is the tube bundle outlet 0. is shown to be the minimum. Note that the pipe bundle central person indicates the position of the intermediate partition plate 21. Now, as shown in the above embodiment, the heating steam chamber and drain chamber of the header 9 are divided into first to fourth heating steam chambers and drain chambers, and the temperature of the heat transfer tube 23 connected to each chamber is increased. The values are ΔTI+ΔT2+ΔTs, ΔT4+ Δ
When T5 + ΔT6 + ΔT 7 +ΔT8, the temperature increase value of the heated steam heated by the outermost heat exchanger tube 23 is ΔTI + ΔT8, and the temperature increase value due to the innermost heat exchanger tube 23 is ΔT4 + ΔT5. The intermediate temperature rise value is ΔT2+ΔT7. ΔT3+ΔT6.

In this way, since the temperature rise value of the heated steam differs for each heat exchanger tube 23, the flow state of the two-phase flow consisting of heated steam and condensed liquid flowing inside each heat exchanger tube 23 differs. Even if one heat exchanger tube 23 is flowing stably,
There may be cases where unstable flow occurs in other items.

Now, the amount of heated steam GHEAT when the heated steam inserted into the heat exchanger tube 23 is completely changed to condensate at the outlet portion 233' of the heat exchanger tube 23, etc. is determined by the following equation.

Here, G, 7 is the amount of steam to be heated, X is the humidity of the heated steam at the inlet of soda lime (hereinafter referred to as the inlet), X is the humidity of the steam to be heated at the inlet, and 11' is the heated steam at the inlet. is the enthalpy of dry steam in the heated steam at the inlet, 12/ is the enthalpy of the heated steam condensate, 11' is the enthalpy of moisture in the heated steam at the inlet, and 7' is the enthalpy of moisture in the heated steam at the inlet. The dry steam enthalpy in the heated steam, I2, indicates the enthalpy of the heated steam at the outlet.

The enthalpy of dry steam 11"+I+" and the enthalpy of moisture iI'+Il' are related to the pressure and temperature of the fluid, but in reality the pressure loss on both the heating steam side and the heated steam side is small, so this The enthalpy of etc. depends mostly on temperature. Therefore, the amount of heated steam ()gzmuT is the enthalpy change Δ■(Δknee ΔT 0UT−ΔT
IN, where ΔTOUT is the temperature rise value on the outlet side of the tube bundle, Δ
E N can be determined relatively easily from N, which indicates the temperature rise value on the tube bundle inlet side, and the enthalpy change Δi of the heated steam.

However, if the heating steam amount GHEAT is completely condensed at the outlet of the heat exchanger tube 23, supercooling will occur as described above, so it is necessary to add a scavenging steam amount ()s to the heat exchanger tube 23 as shown in FIG. .

As introduced in the above-mentioned patent application No. 56-99845,
Classified by the value of W. Here, Gt is the steam flow rate, G
E is the condensate flow rate, ψ and F are characteristic values that change depending on the characteristics of the fluid, and are expressed in (Ft-tb) units by the following equation.

Here, 'rt is the specific weight of vapor, rt is the specific weight of condensate, σ is surface tension, and μt is the viscosity coefficient of condensate.

Therefore, the scavenging steam rate Gs/Ga1er, which is expressed by comparing the scavenging steam amount Gs and the heating steam amount GH]8A, indicates that the flow state determined by the value shown by G4/Gt・ψ・W is a laminar flow, It is necessary to select a flow that provides a stable flow such as a laminar flow.

In FIG. 11, the horizontal axis shows the position of the heat exchanger tubes 23, and the vertical axis shows the amount of heated steam GI introduced into each heat exchanger tube 23.
IIAT, scavenging steam amount Gs and scavenging steam rate Gs, /G
iA]ct e is shown. The heat exchanger tube 23 on the outermost edge side and the heat exchanger tube 23 on the innermost edge side (in the figure, for convenience, the inlet section 23
a, 23d and outlet portions 23a', 23d'), the heating steam amount Gui
AT is different and increases toward the outermost edge. Therefore, in order to obtain a constant scavenging vapor rate Gs/GnxAt (indicated by a dashed line in the figure), the scavenging vapor amount Gs must also increase toward the outermost edge as shown in the figure.

Based on the above theory, the present embodiment of the control method shown in FIG. 14 will be described. As described above, the temperature increase value of the heated steam is compared with the set value, and the heating steam line is controlled by the flow rate control valve 91a etc., and the first to fourth drain chambers 57 to 5 are controlled.
7', '56 56'.

55 55', 54 54' (Figures 7 and 9
Detect the amount of scavenging steam and drain amount flowing out from the flow rate control valve 91a etc. and determine the amount of scavenging steam Gs/GHEATf described above, determine the flow state of the two-phase flow, and transfer the heating steam and scavenging steam to the flow rate control valve 91a etc. It is intended to be adjusted and maintained in a stable state. This prevents all of the heat transfer tubes 23 from being overcooled, providing a stable two-phase flow, and also making it possible to improve the thermal efficiency of the Nagi turbine plant without causing water hammer or the like.

FIG. 15 shows another embodiment of the invention.

In the embodiment described above, the amount of scavenging steam and the amount of drain discharged from the reserve tank 110 were detected, but in this embodiment, the amount of scavenging steam 62a discharged from the first to fourth drain chambers 57°, 56, 55, 54 was detected.

62b, 62c, 62d and drey6ia.

Directly detect the flow rates of 61b, 61c, and 61d, and input these to the scavenging steam amount calculator 75 and the condensed liquid amount calculator 76,
A flow rate control valve (not shown) is used to control the amount of scavenging steam for each. Its action and effect are the same as those of the above embodiment.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, it is possible to prevent supercooling in all heat transferers, maintain a stable flow state, improve safety and reliability, and improve the thermal efficiency of the plant. Improved effects can be achieved.

It should be noted that, as a matter of course, the present invention is not limited to the illustrated embodiment.

[Brief explanation of drawings]

Figure 1 is a schematic cycle configuration diagram of a nuclear power plant equipped with a brackish water separator and reheater, Figure 2 is a control system diagram showing the conventional control method for a brackish water separator and reheater, and Figure 3 is a diagram of the brackish water separator and reheater. General structural diagram of a heating device, Figure 4 is a sectional view taken along the line ■-■ in Figure 3, Figure 5 is a configuration diagram around the header of a conventional reheater, and Figure 6 is Figure 5. FIG. 7 is a sectional view showing a header wheel according to an embodiment of the present invention, FIG. 8 is a cross-sectional view of FIG. 7, and FIG. 10 is a bird's-eye view of FIG. 9, FIG. 11 is a diagram showing the temperature rise characteristics due to the reheater, FIG. 12 is an explanatory diagram showing the addition state of scavenging steam, and FIG. The figure is a diagram showing the characteristics of scavenging steam, and Figure 14 is a diagram suitable for carrying out the present method invention.
FIG. 15 is a control system configuration diagram showing one embodiment, and FIG. 15 is a partial control system configuration diagram of another embodiment. 101...High pressure turbine, 102...Low pressure turbine, 103, 103a, 103b =-Brackish water separator, 104° 104a, 104b--First reheater, 105°105a, 105b-Second Reheater, 106
...Brackish water separation reheater, 108,109... Heat exchanger tube group, 110°112... Reserve tank, 113...
- Feed water heater, 5a, 5b, 5c, 5d...Steam inlet pipe, 6a. 6b, 6c, 6d...-exhaust steam, 7a, 7b, 7c...
...Steam outlet pipe, 8a, sb, 8c...Supply steam, 9
゜10... Header, 11.13... Heating steam pipe, i
2゜14... Drain discharge pipe, 15a, 15b... Drain pipe, 16a, 16b... Drain, 17... Outer shell, 18... Outer corner wall, 19a, 19b... Partition wall , 20a. 20b...Partition wall, 21...Intermediate partition plate, 22...
Tube sheet, 23... Heat exchanger tube, 23a, 23b, 23c,
23d... Inlet part, 23a', 23b', 23c
'. 23d'...Exit part, 24...Heating steam chamber, 25.
...Drain room, 26.27a, 27b, 27c, 27d
... Heating steam, 28a, 28b, 28c, 28d - Drain flow, 29... Drain, 30... Steam, 31...
- Superheated steam, 32b, 32C, 32d, 32b'. 32c', 32d'... Orifice, 32, 33° 34.35, 36.37... Horizontal diaphragm, 32'. 33', 34', 35', 36', 37'...
・Arc-shaped partition plate, 38.38', 39.39', 40.
40', 41.41'...first to fourth heating steam pipes, 48.48', 46.46', 44.44', 4
2.42'...first to fourth scavenging steam pipes, 49.
49', 47.47', 45.45', 4j, 43'・
...first to fourth drain pipes, 50°50', 51.
51', 52.52', 53°53'...first to fourth heating steam chambers, 57°57', 56.56', 55
．． 55', 54° 54'...first to fourth drain chambers, 58, 59 first side wall, 61, 61a, 61b, 61c
, 61d...drain, 62, 62a, 62
b, 62c, 62d...Scavenging steam, 63
．． 64...Temperature difference detector, 66...Scavenging steam pipe, 6
7... Drain pipe, 68... Flow rate control valve, 69.71
...Flow rate detector, 72...Temperature rise detector, 73.
...Comparator, 74...Temperature rise setting device, 75...Scavenging steam amount calculator, 76...Condensed liquid amount calculator, 77...
・Scavenging chamber calculator, 78...Flow pattern determiner, 7
9...Scavenging rate corrector, 83, 84, 85.86...
control signal, 90a, 90b, 90c,
90 d =-・Heating steam, 91a, 91b, 91c
, 91d...-Flow control valve. Foil figure 6 figure q figure q

Claims (1)

[Claims] 1. A brackish water separator that is provided between a high pressure turbine and a low pressure turbine constituting a nuclear turbine plant and that separates moisture from exhaust steam from the high pressure turbine, and the high pressure turbine or nuclear reactor. The heating steam is introduced into a large number of U-shaped heat transfer tubes connected to the header, and the heat transfer tubes are connected to the heat transfer tubes from the brackish water separator. a reheater for exchanging heat with the moisture-separated exhaust steam sent to the outer circumferential side of the heat exchanger tube and discharging drain generated in the heat transfer tube to the reserve tank side via the header. In the header, the closed space is formed by a heating steam chamber and a drain chamber formed by partitioning the closed space with an intermediate partition plate, and the heating steam chamber and the drain chamber are further divided into a plurality of stages. Second
forming heating steam chambers and drain chambers such as, and connecting the corresponding first and second heating steam chambers and drain chambers with the heat transfer tubes held and disposed on the tube plate; Furthermore, the above 1. A heating steam pipe for introducing heating steam from the high pressure turbine or the nuclear reactor is connected to the second heating steam chamber, and a heating steam pipe for introducing heating steam from the high pressure turbine or the nuclear reactor is connected to the first heating steam chamber. A brackish water separation and reheater characterized in that a second drain chamber is connected to a scavenging steam pipe and a drain pipe connected to the reserve tank side. 2. Above 1. The second class heated steam room and drain room are
Claim 1, wherein the heating steam chamber and the drain chamber of the header are divided into a plurality of stages by partition plates arranged in parallel at appropriate intervals. Brackish water separation reheater. 3. Above 1. The second class heated steam room and drain room are
Claim 1, wherein the heating steam chamber and the drain chamber of the header are divided into a plurality of stages by concentric arc-shaped partition plates provided at appropriate intervals. Brackish water separation reheater. 4. The first and second parts formed in the header of the reheater.
The heating steam chamber and the drain chamber, the heating steam pipe, the scavenging steam pipe, and the drain pipe connected thereto, the corresponding heating steam chamber and the drain pipe, and the corresponding heating steam chamber and drain chamber. The scavenging steam is connected to the heat exchanger tube connected between the second heating steam chamber and the drain chamber, and the scavenging steam pipe and the drain pipe, and is discharged from the first and second drain chambers. In the method for controlling a brackish water separation reheater, the method includes controlling the flow rate of the heating steam introduced into the heating steam chamber and the scavenging steam of the reheater having the reserve tank for separating and discharging the water and the drain. A flow rate control valve is provided in the system through which heating steam and scavenging steam flows, detects the temperature difference between the inlet and outlet of the heated steam of each heat transfer tube turner, calculates the temperature rise value, and calculates the temperature increase. The flow rate control valve of the heating steam line is controlled by comparing the detected field value of the rising value with the set value, and the flow rate of the scavenging steam and drain is detected, and from this detection signal, the steam and A brackish water separation and reheater characterized in that the flow state (flow pattern) of the two-phase flow of condensate is completely determined, and the flow rate control valves of the scavenging steam system path and the heating steam system path are controlled based on this. Control method.