JP2019143945A - Method for controlling condensate system, and condensate system and ship with the same - Google Patents

Abstract

To provide a method for controlling a condensate system and a condensate system, each of which enables condensate level inside a condenser to be appropriately maintained even when vacuum state inside the condenser changes, and to provide a ship with the condensate system.SOLUTION: There is provided the method for controlling a condensate system 1 comprising: a condenser 10 condensing steam exhausted from a steam turbine to obtain condensate; a gland condenser 12 heating the condensate from the condenser 10; a tank 14 storing a part of the condensate from the gland condenser 12; a condensate pump 16 provided between the condenser 10 and the condensate inflow side of the gland condenser 12; a condensation level control valve 18 provided between the condensate discharge side of the ground condenser 12 and the condenser 10; and a condenser internal pressure detection part capable of detecting the pressure inside the condenser 10. The method for controlling the condensate system includes: a rotational speed switching step of adjusting the minimum rotational speed of the condensate pump 16 in accordance with the pressure inside the condenser 10, which is obtained by the condenser internal pressure detection part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a condensate system control method, a condensate system, and a ship equipped with the same.

  In a steam turbine provided in a steam plant employed in a ship or a power generation system, a condenser that generates condensate by condensing steam discharged from the steam turbine is known.

  In the invention disclosed in Patent Document 1, when the condensate stored in the condenser hot well provided at the bottom of the condenser is supplied to the deaerator by the condensate pump, the rotation of the condensate pump is performed. The flow rate of the condensate to be supplied is reduced by lowering the number.

JP 2010-270637 A

  In order to maintain the performance of the condenser, non-condensable gas mixed with the steam discharged from the steam turbine and continuously flowing out of the condenser is continuously discharged to the condenser. A vacuum pump that puts the inside of the chamber into a vacuum state may be provided. When the condenser is in a vacuum state, such as when the steam turbine is operating or when the steam turbine is stopped before stopping the steam turbine auxiliary equipment, or when the steam plant is stopped or when the steam turbine auxiliary equipment is started or stopped The capacity required for the condensate pump for sucking condensate may be different from when it is not.

  In the invention disclosed in Patent Document 1, although the flow rate of the condensate to be supplied is reduced depending on the number of rotations of the condensate pump, the vacuum state in the condenser is not taken into consideration, so Depending on the vacuum state, the flow rate may not be properly controlled. In other words, there is a possibility that the condensate level in the condenser cannot be properly maintained.

  The present invention has been made in view of such circumstances, and controls the condensate system that can appropriately maintain the condensate level in the condenser even when the vacuum state in the condenser has changed. It is an object of the present invention to provide a method, a condensate system, and a ship equipped with the same.

In order to solve the above problems, a condensate system control method, a condensate system, and a ship equipped with the condensate system of the present invention employ the following means.
That is, a control method for a condensate system according to one aspect of the present invention includes a condenser that condenses steam discharged from a steam turbine into condensate, and a ground condenser that heats the condensate from the condenser. A tank for storing a part of the condensate from the ground condenser, a condensate pump provided between the condenser and the condensate inflow side of the ground condenser, and a condensate discharge of the ground condenser And a condenser level control valve provided between the condenser and the condenser, and a condenser system pressure detection unit capable of detecting the pressure in the condenser. And a rotational speed switching step of adjusting a minimum rotational speed of the condensate pump according to the pressure in the condenser obtained by the condenser internal pressure detector.

The condensate system control method according to this aspect includes a rotation speed switching step of adjusting the minimum rotation speed of the condensate pump according to the pressure in the condenser obtained by the condenser pressure detector. Here, with regard to the arrangement of the main equipment constituting the condensate system, for example, in order of the head, tank (inflow side), ground condenser (discharge side), ground condenser (inflow side), condenser, condensate pump and Is done. According to this, for example, when the inside of the condenser becomes a low vacuum, the minimum rotational speed of the condensate pump is lowered accordingly (that is, the minimum value of the discharge head of the condensate pump is lowered), The pressure of condensate discharged from the condensate pump can be lowered. Thereby, it is possible to prevent the condensate in the condenser from flowing excessively into the tank through the ground condenser. In other words, the condensate flowing into each of the condenser and tank connected to the discharge side of the ground condenser can be properly secured, so even if the condenser is in a low vacuum, the condenser in the condenser is The water level can be maintained properly. In addition, it is possible to prevent idling of the condensate pump due to a decrease in the condensate level in the condenser. If the condenser head is in a low vacuum and the discharge head of the condensate pump cannot be lowered (that is, if the discharge head remains high during high vacuum), the condensate from the condensate pump The condensate flows into the tank from the ground condenser beyond the head (differential pressure due to the difference in height) due to the discharge of the condenser, and the condensate that should flow into the condenser cannot be secured. There is a possibility that the condensate pump will run idle due to a decrease in the condensate level in the vessel. Note that when the condenser has a high vacuum, compared to when the condenser has a low vacuum, a larger pressure is required to suck in the condensate from the condenser. Even if the minimum value is not lowered, the pressure of the condensate discharged from the condensate pump becomes low when the condensate is sucked from the condenser.
The low vacuum mentioned here is, for example, about -0.5 bar to 0 bar (including atmospheric pressure) in gauge pressure, and the high vacuum is, for example, about -1 bar to -0.5 bar in gauge pressure. The minimum number of rotations is not the actual number of rotations of the condensate pump, but the number of rotations set so that the condensate pump does not operate at a lower number of rotations.

  Further, in the condensate system control method according to an aspect of the present invention, in the rotation speed switching step, a predetermined pressure in which the pressure in the condenser obtained by the condenser pressure detector is determined in advance. When the pressure is exceeded, the minimum rotation speed of the condensate pump is lowered.

In the condensate system control method according to this aspect, in the rotation speed switching step, when the pressure in the condenser obtained by the condenser pressure detection unit is equal to or higher than a predetermined pressure, Reduce the minimum speed of the water pump. According to this, when the inside of the condenser becomes a low vacuum, the condensate pump is reduced by lowering the minimum rotation speed of the condensate pump accordingly (that is, lowering the minimum value of the discharge head of the condensate pump). The pressure of condensate discharged from the pump can be lowered. Thereby, it is possible to prevent the condensate in the condenser from flowing excessively into the tank through the ground condenser. In other words, the condensate flowing into each of the condenser and tank connected to the discharge side of the ground condenser can be properly secured, so even if the condenser is in a low vacuum, the condenser in the condenser is The water level can be maintained properly. Further, it is possible to prevent idling of the condensate pump due to a decrease in the condensate level in the condenser.
The low vacuum referred to here is, for example, about −0.5 bar to 0 bar (including atmospheric pressure) in gauge pressure.

  In the condensate system control method according to one aspect of the present invention, when the pressure in the condenser is a gauge pressure of −0.5 bar or more and 0 bar or less, the minimum rotation speed of the condensate pump is decreased.

  In the condensate system control method according to this aspect, when the pressure in the condenser is a gauge pressure of −0.5 bar or more and 0 bar or less, the minimum rotation speed of the condensate pump is lowered. According to this, when the vacuum state is low, the condensate pump discharged from the condensate pump is reduced by lowering the minimum rotation speed of the condensate pump accordingly (that is, lowering the minimum value of the discharge head of the condensate pump). The water pressure can be lowered.

  Further, the condensate system control method according to one aspect of the present invention provides a maximum opening degree of the condensate level control valve according to the pressure in the condenser obtained by the condenser pressure detection unit. An opening degree switching step of adjusting the angle.

The condensate system control method according to this aspect includes an opening degree switching step of adjusting the maximum opening degree of the condensate level control valve according to the pressure in the condenser obtained by the condenser pressure detector. Including. According to this, for example, when the inside of the condenser becomes a high vacuum, the maximum opening of the condensate level control valve can be lowered accordingly. Accordingly, it is possible to prevent the pressure in the condenser from becoming high (approaching low vacuum) by preventing the opening of the condensate level control valve from becoming larger than necessary. That is, it is possible to prevent the condensate in the condenser from flowing into the tank from the ground condenser due to the discharge of the condensate from the condensate pump operating at the minimum rotation speed. Therefore, the condensate flowing into the condenser connected to the ground condenser can be appropriately secured, so that the condensate level in the condenser can be appropriately maintained. In addition, it is possible to prevent idling of the condensate pump due to a decrease in the condensate level in the condenser. If the opening of the condensate level control valve becomes excessively large, the pressure of the condensate discharged from the condensate pump will increase, and even if the condensate pump is at the minimum rotation speed, Due to the discharge, the condensate passes through the ground condenser and flows into the tank, so that the condensate that should flow into the condenser cannot be secured and the condensate pump is emptied due to a decrease in the condensate level in the condenser. There is a possibility of driving.
The high vacuum referred to here is, for example, about −1 bar to −0.5 bar in gauge pressure. The maximum opening is not the actual opening of the condensate level control valve, but an opening that is set so that the opening of the condensate level control valve does not increase any more.

  Further, in the condensate system control method according to one aspect of the present invention, in the opening degree switching step, a predetermined pressure in which the pressure in the condenser obtained by the condenser pressure detector is determined in advance. When the pressure becomes lower than the maximum pressure, the maximum opening of the condensate level control valve is lowered.

  In the condensate system control method according to this aspect, in the opening degree switching step, when the pressure in the condenser obtained by the condenser pressure detection unit is equal to or lower than a predetermined pressure that is determined in advance, Reduce the maximum opening of the water level control valve. According to this, when the inside of the condenser is in a high vacuum, the condensate passes through the ground condenser due to discharge from the condensate pump even though the condensate pump rotates at the minimum rotation speed. Thus, it is possible to prevent the condensate level in the condenser from being lowered without ensuring the condensate that would have flowed into the tank and supposed to flow into the condenser. That is, since the condensate flowing into the condenser connected to the ground condenser can be appropriately secured, the condensate level in the condenser can be appropriately maintained.

  In the condensate system control method according to one aspect of the present invention, when the pressure in the condenser is −1 bar or more and −0.5 bar or less in gauge pressure, the maximum opening degree of the condensate level control valve is set. Lower.

  The condensate system control method according to this aspect reduces the maximum opening of the condensate level control valve when the pressure in the condenser is −1 bar or more and −0.5 bar or less in gauge pressure. According to this, when the vacuum state is high, the maximum opening of the condensate level control valve can be lowered accordingly. Accordingly, it is possible to prevent the pressure in the condenser from becoming high (approaching low vacuum) by preventing the opening of the condensate level control valve from becoming larger than necessary.

  A condensate system according to an aspect of the present invention includes a condenser that condenses steam discharged from a steam turbine to condense, a ground condenser that heats the condensate from the condenser, and the ground condenser. A tank for storing a part of the condensate from the condenser, a condensate pump provided between the condenser and the condensate inflow side of the ground condenser, a condensate discharge side of the ground condenser and the condensate A condenser level control valve provided between the condenser and a condenser pressure detection unit capable of detecting the pressure in the condenser, the pressure obtained in the condenser pressure detection part A control unit is provided that adjusts the minimum number of revolutions of the condensate pump according to the pressure in the condenser.

  It is possible to provide a condensate system that can appropriately secure the condensate flowing into the condenser connected to the ground condenser and can appropriately maintain the condensate level in the condenser.

  Further, in the condensate system according to one aspect of the present invention, the control unit is configured to control a maximum of the condensate level control valve according to the pressure in the condenser obtained by the condenser pressure detection unit. Adjust the opening.

  It is possible to provide a condensate system that can appropriately secure the condensate flowing into the condenser connected to the ground condenser and can appropriately maintain the condensate level in the condenser.

  Moreover, the ship which concerns on 1 aspect of this invention is equipped with the above-mentioned condensate system.

  According to the condensate system control method, condensate system, and ship equipped with the condensate system according to the present invention, the condensate level in the condenser is appropriately adjusted even when the vacuum state in the condenser has changed. Can be maintained.

It is a block diagram which shows the state in which the condensate has not flowed into the cascade tank in the condensate system which concerns on one Embodiment of this invention. It is a block diagram which shows the state in which the condensate is flowing in into the cascade tank in the condensate system which concerns on one Embodiment of this invention. It is the figure which showed the difference by the vacuum state in a condenser in the flow volume characteristic in the minimum rotation speed of a condensate pump. It is the figure which showed an example of the relationship of the condensate pump rotation speed in the condensate system which concerns on one Embodiment of this invention, the pressure in a condenser, the condensate level in a condenser, and the opening degree of a condensate level control valve. is there.

  Hereinafter, an embodiment of a condensate system control method, a condensate system, and a ship including the condensate system according to the present invention will be described with reference to the drawings.

First, the structure of the condensate system 1 which concerns on this embodiment is demonstrated.
As shown in FIG. 1, the condensate system 1 according to this embodiment includes a condenser 10, a ground condenser 12, a cascade tank (tank) 14, a condensate pump 16, and a condensate level control valve 18, and a pipe W1. , W2, W3 (W3a, W3b). The condensate system 1 includes a TCP (Turbine Control Panel) 20 and a VFD controller (VFD: Variable Frequency Drive) 22. The condensate system 1 is suitable for use in a ship, and is provided in the ship in a form in which the above-described components are accommodated in the ship's hull structure, that is, in a space surrounded by the outer plate 40.

  The TCP 20 and the VFD controller 22 include, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is preinstalled in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

  The above-described components included in the condensate system 1 shown in FIG. 1 are arranged at different height positions in the vertical direction (up and down direction on the paper). For example, in FIG. The inflow side of the tank 14, the discharge side of the ground condenser 12, the inflow side of the ground condenser 12, the condenser 10, and the condensate pump 16 are provided. At this time, the surface on which the condensate pump 16 at the bottom is installed is defined as a reference surface P1, and the surface on which the ground capacitor 12 and the cascade tank 14 are installed is defined as an installation surface P2. The reference plane P1 and the installation plane P2 are each level of the engine room provided in the ship.

The condenser 10 condenses the steam discharged from, for example, a steam turbine (not shown) provided in a steam plant (not shown) that serves as a power source for the ship, and condenses it. A cooling pipe (not shown) is provided at the upper part, and a lower tank (not shown) for storing condensate is provided at the lower part. The steam discharged from the steam turbine is guided into the body of the condenser 10 and is condensed by being cooled by the cooling pipe. As described above, the condensate is temporarily stored in the lower tank.
The condenser 10 is provided with a level meter (not shown) that can measure the liquid level of the condensate in the lower tank. The output signal of the level meter is transmitted to the TCP 20, and the TCP 20 can acquire the condensate liquid level by the level meter.
Further, the condenser 10 includes a vacuum device (not shown) (for example, a vacuum pump) for making the inside of the condenser 10 into a vacuum state from the atmospheric pressure, and a condenser internal pressure detection unit (for detecting the pressure of the condenser 10). These output signals are also transmitted to the TCP 20. A vacuum device (not shown) is controlled to put the condenser 10 into a vacuum state according to a command from the TCP 20. Further, the TCP 20 can acquire the pressure in the condenser 10 by a condenser internal pressure detection unit (not shown).

  The ground condenser 12 condenses the steam leaked from the ground part of a steam turbine or the like (not shown) provided in the ship and condenses it, and uses the condensate stored in the condenser 10 as cooling water. . That is, the leaked steam is cooled by the condensate in the ground condenser 12, and the condensed water is heated by the steam leaked in the ground condenser 12.

  The condenser 10 and the ground condenser 12 (inflow side) are connected by a first pipe W1 through which condensate flows. A condensate pump 16 is provided in the middle of the first pipe W1, and the condensate flow of the condensate system 1 is formed by the condensate pump 16. Further, a discharge pressure detection unit 26 capable of detecting the discharge pressure of the condensate pump 16 is provided on the discharge side of the condensate pump 16 in the first pipe W1.

  The condensate pump 16 is electrically connected to the VFD controller 22, and the VFD controller 22 can change the rotational speed of the condensate pump 16. Further, the VFD controller 22 is electrically connected to the TCP 20, and the rotational speed of the condensate pump 16 is set by a command from the TCP 20. Further, the signal of the discharge pressure detection unit 26 is transmitted to the TCP 20, and the TCP 20 can acquire the pressure of the condensate discharged from the condensate pump 16 by the discharge pressure detection unit 26.

  The ground condenser 12 (discharge side) and the condenser 10 are connected by a second pipe W2 through which condensate flows. A condensate level control valve 18 is provided in the middle of the second pipe W2, and the flow rate of condensate flowing from the ground condenser 12 (discharge side) to the condenser 10 can be adjusted by its opening.

  The condensate level control valve 18 is electrically connected to the TCP 20, and the opening degree of the condensate level control valve 18 is adjusted by a command from the TCP 20.

  The condensate system 1 includes a cascade tank 14. The cascade tank 14 can store a part of the condensate from the ground condenser 12, and is installed upstream of an economizer provided in a ship equipped with the condensate system 1. The stored condensate is stored in the economizer. To be supplied.

  The second pipe W2 connected to the ground condenser 12 (discharge side) and the cascade tank 14 are connected by a third pipe W3 through which condensate flows. That is, a part of the condensate flowing through the second pipe W2 (that is, a part of the condensate from the ground condenser 12) can be guided to the cascade tank 14 by the third pipe W3. A condensate heater 24 is provided in the middle of the third pipe W3, and the condensate flowing through the third pipe W3 can be heated. The third pipe W3 is divided into a third pipe horizontal part W3a installed in the horizontal direction and a third pipe rising part W3b raised from the third pipe horizontal part W3a.

Next, the flow of condensate during operation of the condensate system 1 according to the present embodiment will be described.
As described above, the condensate flowing through the condensate system 1 forms its flow by the condensate pump 16. Hereinafter, the flow of condensate in the condensate system 1 will be described with the condenser 10 as a starting point.

  Condensate stored in the condenser 10 passes through the condensate pump 16 while flowing through the first pipe W1 and flows into the ground condenser 12. The condensate that has flowed into the ground condenser 12 undergoes heat exchange with the ground condenser 12, and then flows into the second pipe W2. The condensate guided to the second pipe W2 passes through the condensate level control valve 18 and returns to the condenser 10. Further, a part of the condensate led to the second pipe W2 is led to the third pipe W3 and flows into the cascade tank 14 under a predetermined condition (described later).

  During operation of the steam turbine or during turbine stop before stopping the steam turbine auxiliary equipment, the pressure in the condenser 10 is high vacuum (for example, about -1 bar to -0.5 bar in gauge pressure) by a vacuum device (not shown). The steam discharged from a steam turbine or the like (not shown) is sucked into the condenser 10.

  At this time, the condensate led to the third pipe W3 by the operation of the condensate pump 16 is the level of the condensate between the third pipe rising portions W3b (between Cm and Fm shown in FIG. 1). The minimum rotation speed (first minimum rotation speed) of the condensate pump 16, that is, the minimum discharge head (lifting height) is set so as to maintain (Gm shown in FIG. 1). Here, Cm is a height between the reference plane P1 (installation position of the condensate pump 16) and the inlet of the cascade tank 14 (hereinafter referred to as “pump-tank height Cm”), and Fm is a reference. The height between the surface P1 (installation position of the condensate pump 16) and the discharge port of the ground condenser 12 (hereinafter referred to as "pump-capacitor height Fm"), Gm is the liquid level height of the condensate. (Hereinafter referred to as “liquid level height Gm”). At this time, the height of the inlet of the cascade tank 14 is equal to the height of the upper end of the third pipe rising portion W3b, and the height of the discharge port of the ground condenser 12 is equal to the height of the lower end of the third pipe rising portion W3b. .

The pressure of condensate discharged from the condensate pump 16 is the head (Bm shown in FIG. 1) of the condenser 10 with respect to the reference plane P1 (installation position of the condensate pump 16). Height Bm ”), the discharge head of the condensate pump 16 (Dm shown in FIG. 1, hereinafter referred to as“ discharge head Dm ”), the pressure in the condenser 10 (Am shown in FIG. 1). And hereinafter referred to as “condenser pressure Am”). That is, the pressure of condensate discharged from the condensate pump 16 can be expressed as Am + Bm + Dm. At this time, the condenser pressure Am becomes a negative value in a vacuum. Further, the liquid level height Gm in the third pipe rising portion W3b is the pressure of condensate discharged from the condensate pump 16 (Am + Bm + Dm), and other pressure loss (hereinafter referred to as “pipe loss Em”). ”). That is, the liquid level height Gm can be expressed by the following equation.
Gm = Am + Bm + Dm-Em
If the same condensate system 1 is used, the pump-condenser height Bm and the pipe loss Em are considered to be equal. Therefore, the liquid level height Gm in the third pipe rising portion W3b is equal to the discharge head Dm, It depends on the condenser pressure Am. Further, if the condenser pressure Am is substantially constant, the liquid level height Gm in the third pipe rising portion W3b depends on the rotational speed of the discharge head Dm, that is, the condensate pump 16. That is, when the rotational speed of the condensate pump 16 increases, the liquid level height Gm increases, and when the rotational speed of the condensate pump 16 decreases, the liquid level height Gm decreases.

  Note that, for example, when the steam plant is stopped or when the steam turbine auxiliary machine is started or stopped, the pressure inside the condenser 10 is low vacuum (for example, about -0.5 bar to 0 bar (including atmospheric pressure) in gauge pressure). It becomes.

  Next, a case where a part of the condensate guided to the second pipe W2 flows into the cascade tank 14 will be described.

  The condensate stored in the condenser 10 is controlled by the TCP 20 so that the liquid level is maintained at a preset liquid level. Specifically, the control of adjusting the liquid level is performed by the TCP 20 comparing the liquid level of the condensate acquired by a level meter (not shown) with a preset liquid level. . In addition, in the following, instructions for devices related to the liquid level control (including the condensate pump 16, the condensate level control valve 18, the VFD controller 22, the discharge pressure detection unit 26, the condenser internal pressure detection unit, etc.) Information acquisition is assumed to be executed by the TCP 20.

  When the level of the condensate stored in the condenser 10 rises, for example, the number of revolutions of the condensate pump 16 is increased to increase the discharge head Dm. If the discharge head Dm increases, the pressure of condensate discharged from the condensate pump 16 increases accordingly, the liquid level height Gm in the third pipe rising portion W3b increases, and the condensate cascades. It flows into the tank 14 (see FIG. 2). As a result, the liquid level can be lowered by guiding the excess amount of the condensate stored in the condenser 10 to the cascade tank 14.

  On the other hand, when the level of the condensate stored in the condenser 10 falls, for example, the number of revolutions of the condensate pump 16 is reduced and the condensate flowing into the ground condenser 12 from the condenser 10 is reduced. By suppressing the flow rate of water, the level of the condensate stored in the condenser 10 can be increased.

  Still, when the liquid level of the condensate stored in the condenser 10 is lowered, the liquid level is maintained by adjusting the opening of the condensate level control valve 18. For example, by increasing the opening of the condensate level control valve 18, the flow rate of the condensate flowing from the ground condenser 12 to the condenser 10 side is increased. Accordingly, the liquid level of the condensate stored in the condenser 10 can be increased by suppressing the flow rate of the condensate flowing from the ground condenser 12 into the cascade tank 14 or preventing the condensate from flowing. .

  In the present embodiment, control is performed by the TCP 20 so as to adjust the minimum number of revolutions of the condensate pump 16 according to the pressure (vacuum state) in the condenser 10 obtained by the condenser internal pressure detector (not shown). Is done. Specifically, when the pressure in the condenser 10 becomes a low vacuum, the minimum rotational speed of the condensate pump 16 is set to a rotational speed lower than the first minimum rotational speed from the first minimum rotational speed described above. It was decided to reduce to the second minimum rotation speed. That is, when the TCP 20 determines that the pressure in the condenser 10 acquired from the condenser pressure detector is high vacuum, the minimum rotation speed is set to the first minimum rotation speed, and the TCP 20 When it is determined that the pressure in the condenser 10 acquired from the water pressure detector is a low vacuum, the minimum rotation speed is set to the second minimum rotation speed (rotation speed switching step). Thereby, as shown in FIG. 3, the ejection head Dm can be changed depending on the vacuum state.

  Here, the second minimum number of rotations means that the condensate guided to the third pipe W3 by the operation of the condensate pump 16 when the pressure in the condenser 10 is low vacuum is generated in the third pipe rising portion W3b. The number of revolutions of the condensate pump 16 is set so as to be a discharge head Dm that keeps the liquid level height Gm in the interval (between Cm and Fm shown in FIG. 1). At this time, the condenser pressure Am of the low vacuum (Am is a negative value in the vacuum state) is higher than the condenser pressure Am of the high vacuum (Am is a negative value in the vacuum state). When it is desired to make the pressure of the condensate discharged from the same at low vacuum and high vacuum, that is, when it is desired to equalize the liquid level height Gm in the third pipe rising portion W3b, the minimum rotational speed of the condensate pump 16 is set. By lowering and lowering the discharge head Dm, the liquid level height Gm is maintained at the same level as at the time of high vacuum even at the time of low vacuum. That is, when the vacuum is high, the condensate pump 16 must draw the condensate at a pressure that is not inferior to the vacuum pressure in the condenser 10, but when the vacuum is low, the vacuum pressure in the condenser 10 is high vacuum. Since it is weaker than the time, it is necessary to reduce the pressure at which the condensate pump 16 draws the condensate in the condenser 10. For this reason, the second minimum rotation speed is lower than the first minimum rotation speed.

  Furthermore, in the present embodiment, control is performed by the TCP 20 so as to adjust the maximum opening of the condensate level control valve 18 according to the pressure in the condenser 10 obtained by a condenser internal pressure detection unit (not shown). Is done. Specifically, when the pressure in the condenser 10 becomes high vacuum, the maximum opening degree of the condensate level control valve 18 is set lower than the maximum opening degree of low vacuum. When the maximum opening of the condensate level control valve 18 in the high vacuum is the first maximum opening and the maximum opening of the condensate level control valve 18 in the low vacuum is the second maximum opening, the TCP 20 When it is determined that the pressure in the condenser 10 acquired from the internal pressure detector is high vacuum, the maximum opening is set to the first maximum opening, and the TCP 20 is acquired from the condenser internal pressure detector. When it is determined that the pressure in the condenser 10 is low vacuum, the maximum opening is set to the second maximum opening (opening switching step). At this time, the first maximum opening is, for example, about 60%, and the second maximum opening is, for example, about 100%.

  The first maximum opening is, for example, the maximum opening of the condensate level control valve 18 set so as not to eliminate the pressure loss of the condensate flowing through the condensate level control valve 18. If the pressure loss at the condensate level control valve 18 is eliminated by excessively increasing the opening degree (when the resistance by the condensate level control valve 18 is reduced), the condensate pump 16 is connected to the condenser 10. When the condensate is drawn from the condensate level control valve 18 side, the pressure required is reduced. That is, a phenomenon equivalent to the increase in the condenser pressure Am occurs. As a result, the liquid level height Gm in the third pipe rising portion W3b, which depends on the discharge head Dm and the condenser pressure Am, increases. Then, the condensate is guided to the cascade tank 14 even though the opening degree is increased (see FIG. 2).

  Here, the above-mentioned low vacuum is, for example, about -0.5 bar to 0 bar (including atmospheric pressure) in gauge pressure, and the high vacuum is, for example, about -1 bar to -0.5 bar in gauge pressure. In this case, the TCP 20 determines the vacuum state in the condenser 10 with −0.5 bar as a threshold value (predetermined pressure). In addition, it cannot be overemphasized that the range and threshold value of a vacuum pressure can be suitably changed with the specification of the condensate system 1. FIG.

  Further, the above-mentioned minimum rotation speed is not the actual rotation speed of the condensate pump 16 but the rotation speed set so that the condensate pump 16 does not operate at a rotation speed lower than that. Furthermore, the aforementioned maximum opening is not an actual opening of the condensate level control valve 18 but an opening set so that the opening of the condensate level control valve 18 does not become any larger.

  FIG. 4 shows the number of rotations of the condensate pump 16, the pressure in the condenser 10, the level of condensate in the condenser 10, and the condensate level control valve 18 in the control of the condensate system 1 described above. An example of the relationship of the opening degree is shown. In FIG. 4, when the pressure (vacuum state) in the condenser 10 is switched from low to high vacuum in the process of changing from atmospheric pressure to high vacuum by a vacuum device (not shown) (see the dashed line in FIG. 4). ), The minimum rotation speed of the condensate pump 16 is increased by the above-described rotation speed switching step, and the second minimum rotation speed is changed to the first minimum rotation speed. Accordingly, the rotational speed of the condensate pump 16 indicated by the solid line in FIG. 4 is also increasing. Further, when the pressure (vacuum state) in the condenser 10 is changed from low vacuum to high vacuum (see the one-dot chain line in FIG. 4), the maximum opening degree of the condensate level control valve 18 is increased by the opening degree switching process described above. The first maximum opening is reached from the second maximum opening. Along with this, the opening degree of the condensate level control valve 18 indicated by the broken line in FIG. 4 also decreases.

The present embodiment has the following effects.
When the inside of the condenser 10 becomes a low vacuum, it is discharged from the condensate pump 16 by lowering the minimum rotation speed of the condensate pump 16 accordingly (that is, lowering the minimum value of the discharge head Dm). The pressure of condensate can be lowered. Thereby, it is possible to prevent the condensate in the condenser 10 from passing through the ground condenser 12 and excessively flowing into the cascade tank 14. That is, it is possible to appropriately secure the condensate flowing into the condenser 10 and the cascade tank 14 connected to the discharge side of the ground condenser 12, so that even if the condenser 10 is in a low vacuum, the condenser 10 The liquid level of the condensate in the water vessel 10 can be maintained appropriately. Further, it is possible to prevent idling of the condensate pump 16 due to a decrease in the level of the condensate in the condenser 10. Temporarily, when the inside of the condenser 10 is in a low vacuum, the discharge head Dm cannot be lowered (that is, the minimum rotation speed of the condensate pump is a set value in a high vacuum, and a high value in a high vacuum. When the discharge head remains as it is), the condensate discharge from the condensate pump 16 causes the ground capacitor 12 to exceed the head difference between the two devices (difference between Cm and Fm shown in FIG. 1) and to the cascade tank 14. Condensate flows in (see FIG. 2), the condensate that should flow into the condenser 10 cannot be secured, and the condensate pump 16 is emptied due to a decrease in the level of the condensate in the condenser 10. There is a possibility of driving.

  Note that when the condenser 10 has a high vacuum, the condenser pressure Am is smaller than when the condenser 10 has a low vacuum, so that the condensate can be obtained without reducing the minimum value of the discharge head Dm. The pressure of the condensate discharged from the pump 16 is lowered.

  Moreover, when the inside of the condenser 10 becomes a high vacuum, the maximum opening degree of the condensate level control valve 18 can be lowered | hung according to this. Accordingly, it is possible to prevent the pressure of the condensate discharged from the condensate pump 16 from being increased by preventing the opening of the condensate level control valve 18 from becoming unnecessarily large during high vacuum. That is, it is possible to prevent the condensate in the condenser 10 from flowing into the cascade tank 14 from the ground condenser 12 due to the discharge of the condensate from the condensate pump 16 operating at the minimum rotation speed. Therefore, since the condensate flowing into the condenser 10 connected to the ground condenser 12 can be appropriately secured, the level of the condensate in the condenser 10 can be maintained appropriately. Further, it is possible to prevent idling of the condensate pump 16 due to a decrease in the level of the condensate in the condenser 10.

1 Condensation system 10 Condenser 12 Ground condenser 14 Cascade tank (tank)
16 Condensate pump 18 Condensate level control valve 20 TCP (control unit)
22 VFD controller 24 Condensate heater 26 Discharge pressure detector 40 Outer plate P1 Reference surface P2 Installation surface W1 First piping (pipe)
W2 Second piping (piping)
W3 3rd piping (piping)
W3a 3rd piping horizontal section (piping)
W3b 3rd pipe rising part (pipe)

Claims (9)

A condenser that condenses the steam discharged from the steam turbine into condensate,
A ground condenser for heating the condensate from the condenser;
A tank for storing a part of the condensate from the ground capacitor;
A condensate pump provided between the condenser and the condensate inflow side of the ground condenser;
A condensate level control valve provided between the condensate discharge side of the ground condenser and the condenser;
A condenser pressure detector capable of detecting the pressure in the condenser; and
A condensate system control method comprising:
A method for controlling a condensate system, comprising: a rotation speed switching step of adjusting a minimum rotation speed of the condensate pump according to the pressure in the condenser obtained by the condenser internal pressure detection unit.   In the rotational speed switching step, when the pressure in the condenser obtained by the condenser internal pressure detection unit is equal to or higher than a predetermined pressure, the minimum rotational speed of the condensate pump is decreased. The method for controlling a condensate system according to claim 1.   The method for controlling a condensate system according to claim 2, wherein when the pressure in the condenser is a gauge pressure of -0.5 bar or more and 0 bar or less, the minimum number of revolutions of the condensate pump is decreased.   2. The condensate according to claim 1, further comprising an opening degree switching step of adjusting a maximum opening degree of the condensate level control valve in accordance with the pressure in the condenser obtained by the condenser pressure detection unit. How to control the system.   In the opening switching step, the maximum opening of the condensate level control valve when the pressure in the condenser obtained by the condenser internal pressure detection unit is equal to or lower than a predetermined pressure determined in advance. The control method of the condensate system of Claim 4 which lowers | hangs.   The condensate system control method according to claim 5, wherein when the pressure in the condenser is a gauge pressure of -1 bar or more and -0.5 bar or less, the maximum opening of the condensate level control valve is lowered. A condenser that condenses the steam discharged from the steam turbine into condensate,
A ground condenser for heating the condensate from the condenser;
A tank for storing a part of the condensate from the ground capacitor;
A condensate pump provided between the condenser and the condensate inflow side of the ground condenser;
A condensate level control valve provided between the condensate discharge side of the ground condenser and the condenser;
A condenser pressure detector capable of detecting the pressure in the condenser; and
With
A condensate system comprising a controller that adjusts the minimum number of revolutions of the condensate pump according to the pressure in the condenser obtained by the condenser internal pressure detector.   The condensate system according to claim 7, wherein the control unit adjusts the maximum opening of the condensate level control valve according to the pressure in the condenser obtained by the condenser internal pressure detection unit. .   A ship provided with the condensate system according to claim 7 or 8.

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