JP2930534B2 - Condensate drain collection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensate drain recovery system for a steam plant, and more particularly to a condensate drain recovery system suitable for a steam turbine plant with low equipment and operation costs.

[0002]

2. Description of the Related Art Generally, in a steam turbine plant, condensed water is recovered and used as boiler feed water, or treated, heated or deaerated as necessary, and reused for various purposes. I have. Therefore, the condensate drain is recovered as much as possible in the steam turbine plant. By the way, since the condensate drain is open to the atmosphere, the only way to recover it is to use a negative pressure condenser (negative pressure condenser). And the vacuum in the condenser drops.

Therefore, conventionally, as shown in FIG. 6, a condensate recovery tank 21 is installed and each drain pipe 5 is connected to the condensate recovery tank.
When the vacuum of the condenser 22 is rising, the condenser 22 is controlled by the pressure difference while controlling the condenser level with the control valve 23 so that air is not sucked in from the condenser recovery tank 21 when the vacuum of the condenser 22 is rising. To collect the drain.

When the vacuum in the condenser 22 is broken, the drain is collected in the condenser 22 by the pump 24. Since the condensate recovery tank 21 collects the drain open to the atmosphere using only the hydrostatic head, the condensate recovery tank 21 needs to be dug underground and installed at a low position. In FIG. 6, reference numeral 12 denotes an atmosphere opening portion, 24a denotes a discharge pipe of a pump, 25 denotes a drain suction pipe, and 26 denotes a check valve.

[0005]

As described above, the conventional condensate drain recovery apparatus requires a condensate recovery tank, a condensate recovery pump, a condensate recovery tank level control valve, and the like, so that the apparatus is complicated. In addition to this, the operation cost is high, and the condensate recovery tank collects the drain open to the atmosphere only by the hydrostatic head.Therefore, it is necessary to dig an underground pit and install a condensate recovery tank at a low position. There is a problem. SUMMARY OF THE INVENTION An object of the present invention is to provide a condensate drain recovery device that solves such problems.

[0006]

In order to achieve the above-mentioned object, in the condensate drain recovery apparatus of the present invention, a head connected to the drain inlet of the condenser and having a height up to the atmospheric pressure (10.3) is provided. M) or more, and a standpipe (second pipe) and a drain pipe connected to a lower end portion (the lowest diameter portion at the bottom) of the seal pipe. The drain pipe is configured to have an overflow port having an overflow height in a range from the lowest open-to-atmosphere portion height to the head height corresponding to the minimum vacuum degree of the condenser operation. That is, the condensate drain recovery device of the present invention, in a steam plant, includes a negative pressure condenser and a seal pipe having an upper end connected to a drain inlet of the condenser, and the seal pipe has a lower end. The height from the inlet to the drain inlet of the condenser is set to be equal to or higher than the atmospheric pressure equivalent head, and the drain pipe and the stand pipe of the steam equipment of the steam plant are connected to the lower end of the seal pipe, respectively. However, the present invention is characterized in that an overflow port having an overflow height in a range from the height of the lowest open portion of the drain pipe to the atmosphere to the head height corresponding to the minimum vacuum degree during the operation of the condenser is provided.

[0007]

In the above-described condensate drain recovery device of the present invention, when the condenser rises in vacuum, the condensate is drained through the drain pipe and the seal pipe.
The drain of the steam equipment is collected in the condenser. When the condenser vacuum is reduced (vacuum break), the drain head overflows from the overflow port of the stand pipe due to the hydrostatic head, and the water seal of the condenser is held. In order to prevent communication, the condensate drain can be collected without installing a condensate collection tank and without sucking air into the condenser.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system diagram showing a condensate drain recovery system according to an embodiment of the present invention, FIG. 2 is a system diagram showing a modification thereof, and FIGS. FIG. 1 to 5, the same reference numerals as those in FIG. 6 indicate substantially the same members.

In FIG. 1, reference numeral 1 denotes a negative-pressure condenser, and a drain outlet pipe 10a of a steam-water separator 10 is connected to a drain inlet 2 of the condenser 1. Also,
A steam extraction pipe 10b of the steam-water separator 10 is connected to a steam return port 2a provided in the gas phase section 11 of the condenser 1.
Along the condenser 1, a seal pipe 3 is disposed substantially vertically, and a steam-water separator 10 is attached to an upper end of the seal pipe 3.

The lower end of the seal tube 3 is bent horizontally to form a bottom-most maximum diameter portion 4. Each drain pipe 5 of each steam device of the steam turbine plant is connected to the end of the bottom end maximum diameter portion 4 of the seal pipe 3 (at a position separated from the lower end of the seal pipe 3). A stand pipe 9 is vertically connected to the portion 4 at a position near the lower end of the seal tube 3. A water filling port 7 is formed at the upper end of the stand pipe 9, and an overflow port 6 is branched in the middle. A closure palate 8 is provided at the water filling port 7.

Here, the reason why the diameter of the lower end of the seal tube 3 is increased is as follows. In other words, the part that is open to the atmosphere
In order to make the condensate drain supplied from the drain pipe 5 having 12 smoothly overflow from the overflow port 6 of the stand pipe 9, that is, to reduce the pressure loss (flow resistance) of the pipe in the middle as much as possible, The diameter of the maximum diameter portion 4 is set to be larger than any drain pipe 5. `` Maximum diameter ''
Has such a technical meaning, but it is not always necessary to increase the diameter. Reference numeral 12 denotes a portion of the drain pipe 5 which is open to the atmosphere, and reference numeral 13 denotes a valve.

In the initial stage (before the operation of the condenser 1),
As shown in FIG. 3, the closing palate 8 is opened, water is injected from the water filling port 7, water is injected until water overflows from the overflow port 6, and then the closing palate 8 is closed. Therefore, at this time, the drain pipe 5 and the stand pipe 9 (including the bottom-most maximum diameter portion 4 of the seal pipe) are filled with water up to a water level indicated by a two-dot chain line AA (overflow level). 1 can be kept in a water seal (the condenser 1 is not in communication with the open-to-atmosphere portion 12). This state is called “initial water filling”.

After the initial filling, the condenser 1 is operated (evacuated). However, since the condenser 1 is in a water-sealed state,
As the condenser 1 operates, the vacuum inside the condenser 1 gradually increases. Before the vacuum rises to a predetermined value or when the vacuum is broken, the condensate drain may temporarily overflow from the overflow port 6 of the stand pipe 9 as shown in FIG. The two-dot chain line BB shows the water level in this state. The condensate drain overflowing from the overflow port 6 is discarded outside the apparatus by a drain pipe (not shown).

As the vacuum in the condenser 1 rises, the condenser 1
The condensate drain is normally collected, and during normal operation, the water levels of the drain pipes 5 and the stand pipes 9 drop, for example, to the position indicated by the two-dot chain line CC in FIG. During the normal operation, the condensate drain is lost in the bottom-most maximum diameter portion 4 of the seal tube 3 so that the water seal does not break (the condenser 1 and the atmosphere opening portion 12 do not communicate with each other). As described above, a difference between the drain inlet 2 of the condenser 1 and the lowest level of the sealing pipe 3 is provided, which is equal to or higher than the atmospheric pressure equivalent head (10.3 meters).

Therefore, the condensate drain is not lost in the bottommost maximum diameter portion 4, and the condenser 1 does not suck in air. Also, the height of the overflow port 6 is lower than the lowest open-to-atmosphere portion 12a, and the lower limit of the degree of vacuum of the operating condenser from the drain inlet 2 of the condenser (when the vacuum state is the worst). The hydrostatic head is 8.9 m for 660 mmHgVac, for example (10.3 m for 760 mmHgVac at 760 mmHgVac). ] Is set higher than the distance.

That is, if the height of the overflow port 6 is higher than the lowest air opening portion 12a, the condensate drain does not flow from the drain pipe 5 toward the stand pipe 9 but the lowest air opening portion 12a. Backflow to this atmosphere open part
It will overflow from 12a. If the height of the overflow port 6 is lower than the hydrostatic head height corresponding to the lower limit of the vacuum degree, the condensate drain is discharged during the operation at the lower limit value of the vacuum degree.
It will continue to overflow more.

A valve 13 is provided at a position closest to the lower end of the seal tube 3 at the bottommost maximum diameter portion 4. This valve 13 is used to close when the condenser 1 is inspected (check whether the condenser is filled with water and there is no leak), and is normally open. Note that the closing palate 8 and the water filling port 7 in the above embodiment are not always necessary, and the same applies to a modified example in which the closing palate 8 and the water filling port 7 are removed from the embodiment of FIG. Action and effect can be obtained.

In this modification, prior to the operation of the condenser 1, the initial filling with drain water introduced from the drain pipe 5 is performed. The upper end opening of the stand pipe 9 functions as the overflow port 6.

As described above, in the condensate drain recovery apparatus of this embodiment, when the vacuum of the condenser 1 is higher than a predetermined value (during normal operation) without installing a condensate recovery tank unlike the conventional apparatus. In the meantime, drain water flows into the condenser 1 through the seal pipe 3 to collect the drain, and when the vacuum of the condenser 1 does not reach a predetermined value (at the time of vacuum break), the hydrostatic head As a result, drain water overflows from the overflow port 6 of the stand pipe 9, and the condenser 1, the seal pipe 3, and the like can be kept in a water-sealed state until the condenser 1 recovers vacuum.

[0020]

As described in detail above, according to the condensate drain recovery apparatus of the present invention, the following effects and advantages can be obtained. (1) When the condenser is broken in vacuum, drain water overflows from the overflow port of the standpipe and can be kept in a water-sealed state until the condenser recovers vacuum. (2) The condensate recovery tank, condensate recovery pump, and condensate recovery tank level control valve in the conventional equipment can be eliminated, and the pits for setting the condensate recovery tank become uneasy. There are advantages.

[Brief description of the drawings]

FIG. 1 is a system diagram of a condensate drain recovery device as one embodiment of the present invention.

FIG. 2 is a system diagram of the modification.

FIG. 3 is a schematic side view showing an initial water-filled state in the operation explanatory view.

FIG. 4 is a schematic side view showing an overflow state in the operation explanatory diagram.

FIG. 5 is a schematic side view showing a normal operation state in the operation explanatory view.

FIG. 6 is a system diagram of a conventional condensate drain recovery device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Condenser 2 Drain inlet 2a Steam return port 3 Seal pipe 4 Maximum diameter part at the bottom 5 Drain pipe 6 Overflow port 7 Water filling port 8 Closing palate 9 Stand pipe 10 Steam-water separator 11 Gas phase section 12 Open to atmosphere 13 valves

Claims (1)

(57) [Claims] 1. A steam plant, comprising: a negative pressure condenser; and a sealing pipe having an upper end connected to a drain inlet of the condenser, wherein the sealing pipe is connected to the condenser from a lower end thereof. The height to the drain inlet is set to be equal to or higher than the atmospheric pressure equivalent head, and the drain pipe and stand pipe of the steam equipment of the steam plant are connected to the lower end of the seal pipe, respectively, and the stand pipe is connected to the drain pipe. A condensate drain recovery device comprising an overflow port having an overflow height in a range from the lowest height of the open-to-atmosphere portion to a head height corresponding to the minimum vacuum when the condenser is operated.