JP3067053B2 - Condenser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condenser for a steam turbine, a control method therefor, and an apparatus therefor, and more particularly to a condenser suitable for removing dissolved oxygen in condensate in a condenser at the time of starting a plant. The present invention relates to a vessel, its control method and its apparatus.

[0002]

2. Description of the Related Art FIG. 7 is an overall configuration diagram of a condenser according to the prior art. At the start of the plant, the switching valve 15 of the condensate recirculation system 13 is opened by passing the cooling water through the condenser tube nest 2,
The switching valve 14 of the condensing system 12 is closed. Then, the condensate in the condenser 1 is drawn out from the condensate outlet 4 by the condensate water supply device 3, and the condensate recirculation system 13 branched from the condensate system 12 connected to the boiler, the switching valve 15, and the condensate heater 16. Nozzle 1
By 9, the condensate is sprayed onto the hot well ceiling plate 26 from below the tube nest 2 in the condenser 1. The condensed water that has fallen into the hot well flows sequentially through the hot well formed as a path by the partition plate 27 and is recirculated. Then, when the air extraction device 25 is operated, the air in the condenser 1 is removed from the extraction port 23 provided in the tube nest 2 by the system 24, and the air is sequentially depressurized to a vacuum state.

[0003] During the depressurization process, steam is introduced into the condenser through the injection pipe 20 to heat the condensate and promote degassing. Further, the heater 16 installed in the condensate recirculation system 13
Heats the condensate and further reduces the degassing time. When the dissolved oxygen reaches the boiler feedwater specified value by the above deaeration operation, the control valve 22 is closed to stop the supply of steam to the injection pipe 20, and the heating in the condensate heater 16 is stopped, and condensate recirculation is performed. The switching valve 15 of the system 13 is closed, and the switching valve 1 of the condensing system 12 is closed.
Open 4 and let water flow through the boiler.

The control devices 30 and 31 control the amount of steam supplied to the injection pipe 20 and the heater 16 based on the internal pressure, the condensate temperature, and the like. By the above-described procedure, the condensed water having the reconstituted dissolved oxygen concentration of about 7,000 to 10,000 ppb at the time of starting the plant can be quickly degassed to the boiler feedwater specified value (about 10 ppb). Incidentally, Japanese Patent Application Laid-Open No. Sho 60-248994 relates to the related art.

[0005]

An operation for starting and stopping every day in a combined cycle power plant or the like, that is, a DSS operation (Dairy operation)
In a condenser used in a plant that implements (Start Stop operation), if a vacuum break occurs to reduce the power of the plant auxiliary equipment, gas such as oxygen dissolves into the condensate in the condenser the next day, Dissolved oxygen concentration is approximately 7,00 in summer
It is as high as around 0 ppb and around 10,000 ppb in winter. Therefore, in a plant without a deaerator,
In order to prevent the boiler from being corroded when starting the plant, operate the condenser to degas until the concentration of dissolved oxygen in the boiler feed water, that is, the concentration of dissolved oxygen in the boiler, becomes less than the specified value (about 10 ppb). There is a need. Also, in a plant that performs DSS operation, shortening the plant startup time is an important issue in plant operation, such as shortening the working hours of workers.

Therefore, conventionally, the deaeration time has been shortened by heating the condensate in the condenser to shorten the plant start-up time. However, the deaeration time required to remove dissolved oxygen in condensed water greatly depends on environmental conditions such as condensate temperature, cooling water temperature, and air temperature. In the conventional technology, optimization based on environmental conditions is not performed. Since driving is often set under severe winter conditions,
Even when it is not necessary, heating is performed, and there is a problem that auxiliary power is used more than necessary.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a condenser for reducing auxiliary power by using an optimal heating equipment according to environmental conditions, a control method therefor, and a device therefor.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to incorporate the relationship between the degassing time and the heating method based on environmental conditions into a control device in advance, and to set the initial values of environmental conditions (detected values at startup).
This can be achieved by properly using a heating method using the minimum auxiliary power required to satisfy the deaeration conditions such as the required value of the deaeration time and the amount of condensate recirculation at the time of starting the plant.

[0009] The above-mentioned object is to condense water or environmental temperature.
Temperature detector for detecting the start-up time
Temperature detected by the temperature detector determined according to the required value
Judge the detection value of the detector at the set temperature
Condensate heating degassing using equipment and condensate degassing without heating
A control device for selecting a method and controlling a plurality of deaeration operations; and
This is achieved by providing

The above object is also achieved by providing a plurality of the condensate heating equipment.
At the initial stage of plant startup in accordance with the required startup time.
Setting of multiple levels of temperature detected by the temperature detector
Judging the detection value of the detector based on the temperature, and
Heat degassing of condensate using one of
No condensate heating degassing and heating with condensate heating equipment
Select the condensate degassing method and control the condensate degassing operation
This is achieved by providing a control device .

[0011] The above object is to condense steam in a condenser.
From the boiler feed pipe
One of the heaters located in the condensate recirculation system
Or by having both .

[0012]

In time to achieve deaeration [action] condenser, Madzu flushed with cooling water in the tube nest by the cooling water supply device, it is opened the condensate recirculation system switching valve which are branched from the condensate system, boiler Close the condensing system switching valve to prevent condensate with high oxygen concentration from flowing into the boiler. Then, the condensate water is fed by the condensate water supply device to the ground steam condenser, a ground seal is applied to the turbine, and the condensate is circulated through the condensate recirculation system. It is atomized to shorten the degassing time. When the gland seal is applied to the turbine, the air in the condenser is extracted by the air extracting device, and at the same time, the dissolved gas such as oxygen in the condensate is extracted to reduce the pressure in the vessel. Condensate
As a thermal facility, for example , an injection pipe installed in a condenser promotes degassing by heating and stirring the condensate by directly introducing steam into the condensate in the condenser. A heater installed in the condensate recirculation system promotes deaeration by heating the condensate.

The heater installed in the condensate recirculation system may be a direct heat exchanger using steam, an indirect heat exchanger, or an electric heater as long as it raises the condensate temperature. And degassing methods with or without these heaters
Select the control device for the degassing operation, condensate temperature and
Is a detector that detects environmental conditions such as the outlet temperature of the heater installed in the condensate recirculation system, the inlet temperature of the cooling water, and the air temperature.
At the beginning of runt detection, a signal indicating the "initial value" is detected,
It is set according to the required start-up time at the initial stage of plant startup.
Determined by the set temperature of the temperature detected by the temperature detector
Depending on the judgment result, the heating equipment is used by switching the control valve or the method not used is selected and the deaeration operation of condensate water is performed.
It is carried out for, degassed by recycling the condensate by the switching of the switching valve
Luke allowed to continue operating, or recirculating a portion, condensate dissolved
When the oxygen concentration deaerates to the boiler water supply specified value, water is supplied to the boiler . According to this deaeration operation, the start time
It can be easily degassed up to the specified boiler water supply value, and the temperature
If the detector temperature is high, perform deaeration without heating.
The amount of steam used in the heating equipment is reduced, and the auxiliary power is reduced.
I can .

Also, a plurality of condensate heating facilities are provided,
Set temperature set to satisfy required value at multiple levels
To determine the initial detected temperature at plant startup.
Multiple condensate heating facilities to use
Select, use or not use depending on ability
Perform deaeration operation (without heating). In this case, startup time is required
By further lowering the calculated value, the time can be significantly reduced .

[0015]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, when the plant is started, the switching valve 15 of the condensing recirculation system 13 is opened and the switching valve 14 of the condensing system 12 is closed by passing the cooling water through the condenser tube nest 2. The condensate in the condenser 1 is drawn out from the condensate outlet 4 by the condensate water supply device 3 and condensed by the nozzle 19 via the condensate recirculation system 13 branched from the condensate system 12 connected to the boiler and the switching valve 15. The condensate is sprayed onto the hot well ceiling plate 26 from the lower part of the tube nest 2 in the vessel 1. The condensed water that has fallen into the hot well flows sequentially through the hot well formed as a path by the partition plate 27 and is recirculated. And the air extraction device 2
When the air conditioner 5 is operated, the air in the condenser 1 is removed from the extraction port 23 provided in the tube nest 2 by the system 24, and the pressure is sequentially reduced to a vacuum state. Heating the condensate during this depressurization process is effective for shortening the degassing time. In a condenser having equipment for directly heating the condensate in the condenser by introducing steam from the injection pipe 20 and promoting deaeration, there are a method of heating using the equipment and a method of not heating depending on environmental conditions. .

Here, a description will be given of a case where a control method as shown by a line A in FIG. 2 is used. The start time required value is T1 in FIG.
When the condensed water temperature and the concentration of dissolved oxygen in the water are used as the detection signals,
When the condensate temperature is equal to or lower than t1, a detection signal of the thermometer 8 is input to the control device 29 through the signal line 34, and a control signal is transmitted from the control device 29 to open the control valve 22 via the signal line 41. And Thereby, steam is introduced from the injection pipe 20, the condensate is heated, and deaeration is promoted. When the condensed water temperature at the “initial” start of the plant is equal to or higher than t1, the thermometer 8
Is input to the control device 29 through the signal line 34, and a control signal is transmitted from the control device 29, and this closes the control valve 22 via the signal line 41. Thereby, deaeration is performed without heating. Further, the detection signal of the dissolved oxygen concentration meter 7 is input to the control device 29 through the signal line 33, and when the concentration of the reconstituted dissolved oxygen falls below the boiler feedwater specified value (about 10 ppb), the control device 29 controls the concentration. A signal is transmitted, and the control valve 22 is closed through the signal lines 41, 38, and 39, the switching valve 15 is closed, and the switching valve 14 is opened.
Stop the condensate recirculation and start supplying water to the boiler. When the control method as described above is adopted, the start time required value T1 can be satisfied, and the auxiliary power can be reduced by reducing the amount of used steam.

Further, according to the control method, when the condensed water temperature at the “initial” start of the plant is equal to or lower than t1, the control valve 22 controls the injection pipe 20.
By adjusting the amount of steam to be introduced into the fuel cell, a control method as shown by a line B in FIG. 2 can be applied, and the amount of used steam can be reduced. 3 and 4 show another embodiment of the present invention. The condenser of this embodiment has a facility for heating the condensate by a condensate heater 16 installed in the condensate recirculation system 13. In such a condenser, a method of heating using the heater and a method of not heating are selected based on the initial value of the environmental condition, and the deaeration operation is controlled. Here, a description will be given of a case where a control method as shown by a line A in FIG. 4 is used. If the required start-up time is T2 in FIG. 4 and the plant start-up “initial” condensate temperature and the condensate dissolved oxygen concentration are adopted as the detection signals, when the plant start-up initial condensate temperature is t2 or less, The detection signal of the thermometer 8 is input to the control device 29 through the signal line 34, and the control signal is transmitted from the control device 29 to open the control valve 18 via the signal line 40. As a result, the condensate heater 1 directly exchanges heat with steam.
The condensate is heated by 6 to promote degassing. Further, when the condensed water temperature at the “initial” start of the plant is equal to or higher than t2, the detection signal of the thermometer 8 is input to the control device 29 through the signal line 34,
A control signal is transmitted from the control device 29 to close the control valve 22 via the signal line 40, and degassing is performed without heating. Furthermore,
When the detection signal of the dissolved oxygen concentration meter 7 is input to the control device 29 through the signal line 33 and the concentration of the reconstituted dissolved oxygen falls below the boiler feedwater specified value (about 10 ppb), the control device 2
9, a control signal is transmitted, and the control valve 18 is closed, the switching valve 15 is closed, and the switching valve 14 is opened via the signal lines 40, 38, 39 to stop the condensate recirculation. Start supplying water to the boiler. When the control method as described above is adopted, the required start time T2 can be satisfied, and the power of the auxiliary equipment can be reduced by reducing the amount of used steam.

Further, when the condensed water temperature at the “initial” start-up of the plant is equal to or higher than t2 by the control method, the amount of steam introduced into the condensate heater 16 is adjusted by the control valve 18 so that the line B shown in FIG.
Can be applied, and the amount of steam used can be reduced.

FIGS. 5 and 6 show another embodiment of the present invention, in which steam is introduced from an injection pipe 20 to heat condensate to promote deaeration, and a condensate recirculation system 13. In the condenser having both of the equipment for heating the condensate by the condensate heater 16 installed in the middle, depending on the initial value of the environmental conditions, a method of heating using both, or a method of heating using either one And a method of selecting either a heating method or a heating method. When the start-up time request value is T3 in FIG. 6 and the plant start-up “initial” condensate temperature and the condensed water dissolved oxygen concentration are selected as detection signals, the plant start-up “initial” condensate temperature is t
In the case of 3 or less, the detection signal of the thermometer 8 is inputted to the control device 29 through the signal line 34, the control signal is transmitted from the control device 29, the signal passes through the signal lines 40 and 41, and the control valves 18 and 22 are set to ""Open", steam is directly introduced from the injection pipe 20 to the condensate in the condenser and heated, and the condensate is heated by the condensate heater 16 to promote deaeration.

Further, the condensate temperature at the “initial” start of the plant is t
When the value is 3 or more and t4 or less, the detection signal of the thermometer 8 is
The control signal is transmitted from the control device 29 to the control valve 29 through the signal lines 40 and 41, the control valve 18 is closed, the control valve 22 is opened, and the steam is supplied from the injection pipe 20. It is directly introduced into the condensate in the condenser and heated to promote deaeration. In addition, the “initial” condensate temperature at plant startup is t4 or more and t
At 5 or less, the detection signal of the thermometer 8 is input to the control device 29 through the signal line 34, the control signal is transmitted from the control device 29, and the control valve 18 is "opened" through the signal lines 40 and 41,
The control valve 22 is closed, and the condensate is heated by the condensate heater 16 to promote deaeration. Also, the plant startup “initial”
When the condensate temperature is equal to or higher than t5, a detection signal of the thermometer 8 is input to the control device 29 through the signal line 34, and a control signal is transmitted from the control device 29 to control the control valve 1 through the signal lines 40 and 41.
8. Close 22, and degas without heating. Furthermore,
When the detection signal of the dissolved oxygen concentration meter 7 is input to the control device 29 through the signal line 33 and the concentration of the reconstituted dissolved oxygen falls below the boiler feedwater specified value (about 10 ppb), the control device 2
9, a control signal is transmitted, and signal lines 40, 41, 38, 3
9, the control valves 18 and 22 are closed and the switching valve 15 is closed and the switching valve 14 is opened to stop condensate recirculation.
Start supplying water to the boiler.

When the above-described control method is employed, the condensate is heated by both the condensate heater 16 and the equipment for heating the condensate by introducing steam from the injection pipe 20 to promote the deaeration. Assuming that the steam amount is 100%, the steam is injected into the injection pipe 20.
The amount of steam used in the system in which the condensate is heated only by the equipment that heats the condensate and heats the condensate to promote degassing is approximately 70%,
The amount of steam used in the method of heating the condensate by only the condensing heater 16 is about 30%, and the amount of steam used when both heating methods are not used is 0%. T3 can be satisfied, and a reduction in auxiliary power due to a reduction in the amount of used steam can be achieved.

Further, according to the control method, when the condensed water temperature at the “initial” start of the plant is equal to or lower than t5, the amount of steam introduced into the injection pipe 20 and the amount of steam supplied to the condensate heater 16 are controlled by the control valves 18 and 22. Adjustment can further reduce the amount of used steam.

Note that the same control method can be applied when the detection signal is a signal from the cooling water temperature “initial” 10 at the start of the plant. As described above, the condensing heater 16 may be a direct heat exchanger using steam, an indirect heat exchanger, or an electric heater as long as it can raise the condensing temperature. still,
In the above-described embodiment, the example of the condensate temperature is described as the temperature detected by the temperature detector. However, other environmental condition temperatures , for example, the initial values such as the inside temperature, the air temperature, and the cooling water temperature are detected and controlled. It goes without saying that things can be done.

[0024]

According to the present invention, heating degassing or deheating without heating using an optimum heating equipment according to the initial value of environmental conditions.
The power method can be selected, and the auxiliary power can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a condenser according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a control method in the condenser shown in FIG.

FIG. 3 is an overall configuration diagram of a condenser according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating a control method in the condenser shown in FIG.

FIG. 5 is an overall configuration diagram of a condenser according to still another embodiment of the present invention.

FIG. 6 is a diagram illustrating a control method in the condenser shown in FIG.

FIG. 7 is an overall configuration diagram of a conventional condenser.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Condenser, 2 ... Tube nest, 3 ... Condenser water supply device, 4 ... Condenser outlet, 5 ... Grand steam condenser, 6 ... Flow meter, 7 ... Dissolved oxygen concentration meter, 8, 9, 10 ... Thermometer, 11 ... pressure gauge, 1
4, 15: switching valve, 16: condensate heater, 18, 22: control valve, 19: nozzle, 20: injection pipe, 23: air extraction port, 25: air extraction device, 26: hot well ceiling plate,
27: partition plate, 28: cooling water supply device, 29, 30, 3
1 ... control device, 32, 33, 34, 35, 36, 37,
38, 39, 40, 41, 42, 43 ... signal lines.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hitoshi Horibe 3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Plant (56) References JP-A-59-3106 (JP, A) JP-A-60-169084 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F28B 11/00 F28B 9/10

Claims (3)

(57) [Claims] 1. A condenser having a condensate heating facility and performing a deaeration operation for removing dissolved oxygen and the like in condensate water at the time of starting a plant, comprising: a temperature detector for detecting a condensate temperature or an environmental temperature; Heat deaeration of condensed water using the condensate heating equipment by judging the detected value of the temperature detector at a set temperature of the temperature detected by the temperature detector determined corresponding to the start time request value at the initial start-up. A condenser comprising a control device for controlling a deaeration operation of the condensate by selecting a deaeration method of the condensate without heating. 2. The condenser according to claim 1, further comprising a plurality of the condensate heating facilities, wherein a plurality of levels of temperatures detected by the temperature detector determined in correspondence with a start-up time request value at an initial stage of plant start-up. At a set temperature, the detection value of the temperature detector is determined, and one of the plurality of condensate heating devices is selectively used for heating and deaeration of condensate water, and heating and degassing of condensate water using a plurality of condensate heating devices in combination. A condenser comprising a control device for controlling a deaeration operation of the condensate by selecting an air and a deaeration method of the condensate without heating. 3. The condenser according to claim 1, wherein the condensate heating facility is branched from a facility for injecting steam into the condensate in the condenser and heating the condensate, and a boiler feed pipe. A condenser comprising one or both of heaters arranged in a condenser recirculation system.