JPH08261665A - Operating method of cooling water pump for condenser - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a method of operating a condenser cooling water pump that suppresses the wasteful power consumption of the cooling water pump while keeping the degree of vacuum of the condenser at an appropriate value. [Structure] The controller 6 calculates the required cooling water amount based on the temperature signal from the thermometer 7 and the flow rate signal from the flow meter 11, supplies each opening command to the control valve 9, and also determines the required cooling water amount. A drive command is supplied to the pumps 1 that can be supplied. When the controller 6 determines that the degree of vacuum from the vacuum gauge 10 is equal to or less than the specified value and the opening degree of the control valve 9 is the upper limit, the combination of the pumps 1 to be operated is corrected, The vacuum degree of each condenser 2 is corrected to an appropriate value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a condenser cooling water pump for supplying cooling water to a condenser of a steam turbine.

[0002]

2. Description of the Related Art As a conventional method for adjusting the amount of cooling water supplied to a condenser of a steam turbine by a cooling water pump, for example, Japanese Patent Laid-Open Publication No. 2-305302 (referred to as a first conventional example) and Japanese Patent Laid-Open Publication No. Sho. 61-197992 (referred to as a second conventional example) and JP-A-61-3992 (the third example).
(Referred to as a conventional example).

In the first conventional example, the amount of cooling water supplied to the condenser is calculated based on the steam flow rate to the condenser and the temperature of the cooling water, and the steam flow rate to the condenser, the cooling water quantity, and the cooling water are further calculated. Calculate the current power generation output based on the temperature and the power of the cooling water pump that supplies the cooling water to the condenser, and then calculate the deviation of the power generation output when the amount of cooling water is increased or decreased. The deviation of the power of the steam cooling water pump is calculated, and the value of the deviation of the power output of the cooling water pump minus the deviation of the power of the cooling water pump is calculated to be the maximum amount of cooling water,
The number of rotations of the cooling water pump is controlled so that the cooling water amount is obtained, and the obtained cooling water amount is supplied to the condenser.

As a result, the amount of the cooling water supplied to the condenser is optimized so that the effective power generation amount of the entire power generation plant including the loss due to the power consumption of the cooling water pump which is the auxiliary device of the power generation plant becomes the most efficient. To control. Further, in the second conventional example, as the cooling water pump for supplying the cooling water to the condenser of the steam turbine, the main pump whose rotational speed is controlled and the sub pump whose rotational speed is not controlled are provided and The amount of cooling water supplied to the condenser is calculated based on the degree of vacuum of the water condenser, and when the cooling water quantity is low, the water quantity is controlled by controlling the rotation speed of the main pump. The sub pump is also driven.

As a result, the required amount of cooling water is secured and the power consumption used in the cooling water pump is suppressed. Further, in the third conventional example, the amount of cooling water supplied to the condenser is obtained according to the temperature of the condenser discharged from the condenser,
By adjusting the discharge flow rate from the cooling water pump so as to obtain the amount of cooling water, the temperature of the condensate water is kept constant.

[0006]

In the first conventional example described above, one unit is provided so that the amount of cooling water is determined from the flow rate of steam to the condenser and the temperature of the cooling water supplied to the condenser. Controls the speed of the cooling water pump. As a result, when the rotation speed of the pump is increased to supply the cooling water at a high flow rate, the power consumption of the pump increases in proportion to the cube of the rotation speed, so that the cooling water is supplied to the condenser. There is a problem that the power consumption of the cooling water pump increases significantly as the amount of cooling water used increases.

Further, if the steam in the condenser cannot be sufficiently cooled only by the amount of cooling water for the steam flow rate calculated in advance due to an unexpected reason such as deterioration of efficiency of the condenser, The degree of vacuum of the water container may drop below the specified value, which may adversely affect the amount of power generation. At this time,
Even if it is configured to predict a decrease in the degree of vacuum from fluctuations in the vapor flow rate, the vapor flow rate changes due to factors other than the above vacuum degree, and the degree of vacuum is less than a predetermined reference value due to the vapor flow rate. At the time when it is detected that it has become, the degree of vacuum may have already dropped significantly.

Further, in the second conventional example, since the amount of cooling water to be supplied is adjusted only by the degree of vacuum of the condenser, the degree of vacuum can be prevented from falling below the specified value, but cooling can be avoided. If the water temperature is low, the condensate will be cooled too much. This causes unnecessary power consumption by driving the pump more than necessary, and also leads to an increase in fuel consumption because the condensate that has been excessively cooled must be steam-heated again to the specified temperature, resulting in energy saving. Is not preferable from the viewpoint of.

Further, in the third conventional example, the amount of cooling water to be supplied is adjusted only on the basis of the temperature of the condensate discharged from the condenser so that the condensate temperature becomes an appropriate temperature. The degree of vacuum of the condenser is controlled to be within the proper range. Therefore, because it does not detect changes in the flow rate of cooling steam and changes in the temperature of the cooling water that affect cooling efficiency,
Even if the degree of vacuum is lowered to a predetermined value or higher due to the increase or decrease of the steam flow rate or the temperature change of the cooling water, there is a possibility that the proper adjustment of the amount of cooling water with respect to the reduction of the degree of vacuum may be delayed. In other words, if a situation occurs in which the degree of vacuum drops significantly, the amount of cooling water is not adjusted until the degree of vacuum actually drops below the specified value, and the range of change in vacuum is appropriate. There is a risk of exceeding the range. This is not preferable because it leads to unnecessary fluctuations in power generation.

Further, in the third conventional example, the amount of cooling water supplied is adjusted by adjusting the discharge flow rate of one cooling water pump. Therefore, as the amount of cooling water increases, the power consumption of the pump is almost the same. Increases in proportion to the cube of the rotation speed of
There is also a problem that the power consumption of the cooling water pump increases significantly as the amount of cooling water that supplies the cooling water to the condenser increases.

The present invention has been made in view of the above problems, and the condenser cooling water for suppressing the wasteful power consumption of the cooling water pump while keeping the vacuum degree of the condenser at an appropriate value. It is intended to provide a method of operating a pump.

[0012]

In order to achieve the above object, a method of operating a condenser cooling water pump according to the present invention is a condenser for supplying cooling water to a condenser by a plurality of cooling water pumps. In the cooling device, the amount of cooling water supplied to the condenser is calculated based on the flow rate of steam sent to the condenser and the temperature of the cooling water supplied to the condenser, and the calculated amount of cooling water is supplied. The number of the cooling water pumps required to drive the cooling water pumps is driven, and the number of the cooling water pumps to be driven is corrected based on the degree of vacuum of the condenser.

[0013]

In the method for operating the condenser cooling water pump according to the present invention, the amount of cooling water to be supplied is calculated according to the flow rate of steam to be cooled, and the amount of cooling water is controlled by the temperature of the cooling water which affects the cooling efficiency. Since it is corrected, an appropriate amount of cooling water is calculated, and excessive cooling of the condensate is prevented.

Since only the number of cooling water pumps corresponding to the required amount of cooling water is operated, only a minimum number of pumps are operated. At this time, since a plurality of pumps are driven to supply the cooling water, the load per pump is reduced. Also, even if the degree of vacuum, that is, the amount of power generation may change due to changes in the steam flow rate and cooling water temperature, the number of pumps that can be driven immediately before the degree of vacuum or the amount of power generation changes above a certain level. It is also possible to prevent changes by responding to changes.

Further, even if the degree of vacuum of the condenser changes due to factors other than the steam flow rate and the temperature of the cooling water, the number of cooling water pumps operated based on the change in the degree of vacuum. Is corrected and the degree of vacuum of the condenser is suppressed within a predetermined appropriate range.

[0016]

An embodiment of the present invention will be described with reference to the drawings.
First, the configuration of the condenser cooling device will be described. In this embodiment, as shown in FIG. 1 which is a condenser cooling water system diagram,
Cooling water is supplied to a plurality of condensers 2 by a plurality of cooling water pumps 1. In addition, 3 has shown the turbine corresponding to each condenser 2.

The plurality of pumps 1 are arranged in parallel, and the discharge port side thereof is connected to one shared communication pipe 4. The connection pipe 4 is connected to each condenser 2 via an individual supply pipe 5 so that cooling water can be supplied to all the condensers 2. The pump 1 is capable of sucking seawater or lake water used as cooling water, and its drive is individually controlled by a command from the controller 6. Moreover, the performance of each pump 1 is not the same.

A thermometer 7 is connected to the connecting pipe 4 so that a temperature signal based on the temperature of the cooling water measured by the thermometer 7 can be supplied to the controller 6. Also,
A discharge pipe 8 for discharging the used cooling water is connected to each of the condensers 2. A cooling water control valve 9 is inserted in each of the discharge pipes 8 so that each condenser 2
It is possible to adjust the amount of cooling water supplied to the. The opening of each control valve 9 is controlled by a command from the controller 6. In addition, 9a is a motor which operates the valve of each regulating valve 9.

A vacuum gauge 10 is connected to each of the condensers 2, and the pressure value measured by each vacuum gauge 10 can be supplied to the controller 6 as a vacuum degree signal.
A flow meter 11 for measuring the flow rate of steam is connected to the inlet side of the turbine 3 that sends steam to each condenser 2.
1 makes it possible to measure the flow rate of steam sent to the turbine 3, that is, to the condenser 2. Each flow meter 11
Can supply the measured flow rate signal to the controller 6.

The controller 6 calculates the amount of cooling water supplied to each condenser 2 and the amount of cooling water for the entire system based on the signals from the thermometer 7, the flow meter 11 and the vacuum gauge 10, and Based on the calculated value, it is possible to supply an opening command to each control valve 9 and a drive command to the required number of pumps 1. As shown in FIG. 2, the controller 6 mainly includes a required cooling water determination unit 12, a correction unit 13, a drivable pattern table creation unit 14, and an operation pattern determination unit 15.

Further, the controller 6 has a total operation pattern table 16 consisting of all the combination patterns of the plurality of cooling water pumps 1 and the water supply capacity by the combination of the pumps 1 constituting each combination pattern. ing. The combination patterns are prioritized according to the water supply capacity. When the water supply capacity is the same, the priority order is determined according to the efficiency of the pump 1 and the like.

Then, information 17 indicating whether or not each pump 1 can be used.
Each time the operator inputs, the operable pattern creating section 14 operates, and the operable pattern table 18, which is a combination pattern of the operable pumps 1, can be created based on the all operable pattern table 16. ing. Further, the required cooling water determination unit 12 can calculate the required cooling water amount A for each condenser 2 unit based on the temperature signal and the flow rate signal input from the thermometer 7 and the flow meter 11 by the following formula. Has become.

A = Q × K (T) Here, Q represents the steam flow rate measured by each flow meter 11, and K (T) represents the cooling water conversion coefficient. The cooling water conversion coefficient K (T) is a value obtained in advance from the difference in the amount of heat held per unit amount of steam at the inlet and outlet of the condenser 2,
The temperature T measured by the thermometer 7 is a value automatically corrected based on the graph as shown in FIG.
Increase or decrease in proportion to.

Although FIG. 3 illustrates a graph in which the temperature T of the cooling water and the cooling water conversion coefficient K are linearly proportional to each other, in reality, data is collected in a trial run and the graph Determine the curve. Further, the required cooling water determination unit 12
Supplies an opening degree command based on each of the calculated cooling water amounts A to each of the control valves 9 and the correction unit 13, and outputs a signal corresponding to the total cooling water amount obtained by adding the calculated cooling water amounts A to the operation pattern determination unit. 15 can be supplied.

Based on the operable pattern table 18, the operation pattern determination unit 15 selects the combination pattern having the lowest water supply capacity among the combinations capable of supplying the total amount of cooling water supplied, and the pump of the selected pattern. 1 can be notified to the pump operation command output unit 19. The pump operation command output unit 19 can supply a drive signal to the corresponding pump 1 and a stop signal to the other pumps 1.

Further, the correction unit 13 sends an opening correction signal of the opening of the control valve 9 of each condenser 2 based on the fluctuation of the degree of vacuum of each condenser 2 from the vacuum gauge 10 to the required cooling water. It can be supplied to the determination unit 12. Further, when it is detected that the degree of vacuum of the condenser 2 is equal to or less than the specified value and the opening degree of the control valve 9 is the upper limit, a command for operating the combination pattern of the water supply capacity one level higher is determined. It can be supplied to the operation pattern determination unit 15 via the unit 12.

Next, a cooling water pump 1 using the above device
The driving will be described. In the above device, the controller 6 uses the availability information 17 of each pump 1 by the operator.
The operable pattern table 18 is updated every time there is an input. In addition, the required cooling water determination unit 1 of the controller 6
In 2, the operation is performed by correcting the cooling water conversion coefficient K (T) by the temperature signal from the thermometer 7 and calculating the required amount of cooling water to be supplied to the condenser 2 based on the flow signal from each flow meter 11. In addition to being supplied to the pattern determination unit 15, an opening command according to the amount of cooling water supplied to each condenser 2 is supplied to each control valve 9.

The operation pattern determination unit 15 which has received the signal corresponding to the required cooling water amount selects the pattern having the lowest water supply capacity among the combination patterns capable of supplying the required cooling water amount based on the operable table 18. Then, the drive command is supplied to the pump 1 corresponding to the pattern via the pump operation command output unit 19. As a result, only the minimum necessary pump 1 is driven, and an appropriate amount of cooling water supplied by the pump 1 is supplied to each condenser 2.

In parallel with the above processing, the correction unit 13 of the controller 6 detects the variation of each vacuum degree by the vacuum degree signal of each condenser 2 supplied from the vacuum gauge 10, and based on the detected variation. A command for correcting the opening degree of each control valve 9 is supplied to each control valve 9 via the required cooling water determination unit 12.
By this, the amount of cooling water to each condenser 2 is adjusted,
The degree of vacuum of each condenser 2 is controlled so as to be in an appropriate range.

Further, when the correction unit 13 determines that the degree of vacuum is equal to or less than the specified value and the opening of the corresponding control valve 9 is the upper limit, the adjustment of the opening of the control valve 9 alone causes the vacuum. Since the degree cannot be adjusted, a command to operate in the combination pattern of water supply capacity one level higher is supplied to the operation pattern determination unit 15 via the required cooling water determination unit 12.
As a result, the combination of pumps 1 to be operated is corrected, the amount of cooling water supplied is increased, and the vacuum degree of each condenser 2 is corrected to an appropriate value.

As described above, in this embodiment, the amount of cooling water to be supplied is calculated according to the flow rate of steam to be cooled, and
The amount of cooling water is corrected by the temperature of the cooling water that affects the cooling efficiency. As a result, an appropriate amount of cooling water is calculated and excessive cooling of the condensate is prevented, so that wasteful fuel consumption when the condensate is steam-heated by the heater again can be suppressed.

Further, since only the number of cooling water pumps 1 corresponding to the required amount of cooling water is operated, it is possible to suppress wasteful power consumption when driving the pumps 1. At this time, since the plurality of pumps 1 are driven to supply the cooling water, the load per one pump is reduced. Further, even if the vacuum degree of the condenser 2 is lowered due to factors other than the steam flow rate and the temperature of the cooling water such as deterioration of efficiency of the condenser 2, the operation is performed based on the change of the vacuum degree. The number of cooling water pumps 1 that are used is corrected, and the degree of vacuum of the condenser 2 is suppressed within a predetermined appropriate range.

In the above embodiment, the cooling water is supplied to the plurality of condensers 2 by the plurality of cooling water pumps 1, but one condenser is constituted by the plurality of cooling water pumps 1. The configuration of the system that supplies the cooling water to 2 may be used. Further, in the above-described embodiment, the case where the performances of the respective cooling water pumps 1 are different is illustrated, but if the performances of all the cooling water pumps 1 are the same, it is possible to operate without having a combination pattern of the pumps 1. It suffices to control so as to drive the required number of arbitrary pumps 1 among the various pumps 1.

[0034]

As described above, in the operating method of the condenser cooling water pump of the present invention, the minimum required amount of cooling water that does not excessively cool the condensed water is calculated, and the calculated cooling is performed. Since only the minimum pump that can supply the amount of water is operated, there is an effect that it is possible to suppress wasteful power consumption when driving the pump.

Further, since the condensate water is not excessively cooled, the fuel consumption for steam heating the condensate water again is not increased.
Also, in the normal operation state, an appropriate amount of cooling water based on the temperature of the cooling water and the flow rate of steam is supplied to the condenser to adjust the degree of vacuum of the condenser to an appropriate range, and the degree of vacuum is raised due to some trouble. Even if it decreases, the number of pumps to be operated is corrected based on the degree of vacuum, so that the degree of vacuum can be suppressed within an appropriate range, and a stable power generation amount can be obtained.

[Brief description of drawings]

FIG. 1 shows a condenser cooling water system diagram of an embodiment according to the present invention.

FIG. 2 is a block diagram showing a controller according to an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a cooling water conversion coefficient and temperature in an example according to the present invention.

[Explanation of symbols]

 1 Cooling Water Pump 2 Condenser 3 Turbine 4 Connecting Pipe 6 Controller 7 Thermometer 9 Control Valve 10 Vacuum Gauge 11 Flowmeter 12 Required Cooling Water Determining Section 13 Correcting Section 15 Operation Pattern Determining Section

Claims (1)

[Claims] 1. In a condenser cooling device for supplying cooling water to a condenser by a plurality of cooling water pumps, the flow rate of steam sent to the condenser and the temperature of cooling water supplied to the condenser. The amount of cooling water to be supplied to the condenser is calculated based on, and the number of the cooling water pumps required to supply the calculated amount of cooling water are driven, and further, based on the degree of vacuum of the condenser. A method for operating a condenser cooling water pump, characterized in that the number of driven cooling water pumps is corrected.