JPH10300013A - Feed water pump warming up method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate water hammering and cavitation generated from feed water retained in a pipe. SOLUTION: This feed water pump warming up method comprises processes. In one process, feed water 71 supplied to a deaerator 55 from a feed water heater 54 is branched and supplied to a feed water pump 51a as heated feed water through a warming system 72a to warm the feed water pump 51a and in another process, the heated feed water cooled by the warming of the feed water pump 51a is reversed into a deaerator water storage tank 56 through a feed water pump suction pipe 63a and a deaerator down pipe 60a to effectively lower the temperature of the feed water 71 retained in the feed water pump suction pipe 63a and the deaerator downcomer 60a below a prescribed temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator downcomer and a feed pump suction pipe which are connected to a suction side of a feed pump for a boiler and supply the water stored in a deaerator storage tank to the feed pump. The present invention relates to a water supply pump warming-up method for warming a water supply pump in a standby state while preventing staying water from becoming hot water.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing an example of a boiler feedwater pump system conventionally used generally. As shown in the figure, the boiler feedwater pump system condenses steam discharged from the plant, deaerates the air contained in the condensate water to supply water, and replenishes water when water shortages occur. It comprises a replenishing device 49 and a boiler water supply device 50 for supplying water to the boiler.

[0003] Further, the boiler water supply device 50 is usually A,
B, C, and three water supply systems;
It consists of a warming system attached to B and C. That is, each of the water supply systems A, B, and C is provided with a water supply pump 51a, 51b, or 51c capable of supplying a water supply amount corresponding to 50% of a rated boiler capacity (not shown) to the boiler load. In addition to supplying a water supply in accordance with the water supply pump 51, a warming system is provided to cope with the fluctuation of the water supply amount which fluctuates according to the boiler load.
Each of the water supply systems a, 51b, and 51c can be kept in a standby state so that the water supply system can be immediately activated to supply the required water supply to the boiler.

[0004] Next, a path for supplying water to the boiler using the boiler water supply pump system will be described. In the water supply unit 49, the water 71 discharged from the steam turbine or the like, condensed, and stored in the condenser 52 is pumped out by the condensate pump 53, and extracted water from the steam turbine is condensed by the condensate pipe 57. , And is supplied to a feed water heater 54 for increasing the temperature by heating with steam. The loss of the water supply 71 due to the steam flowing out of the plant is supplied at any time by a supply pipe (not shown) connected to the condenser pipe 57.
The feed water heaters 54 are usually provided in parallel, but only one of them is shown in the figure.

The feed water 71 heated by the feed water heater 54 is
The deaerator 5 is provided by the condenser 57 in which the check valve 58 is disposed.
5 is supplied. The water supply 71 supplied to the deaerator 55 is
Heated steam such as extracted steam supplied by the steam pipe 59 is heated and degassed and stored in the deaerator storage tank 56.

Next, in the boiler water supply device 50, the water supply 71 stored in the deaerator water storage tank 56 is supplied to one of three water supply systems A, B and C according to the load of the boiler. The water is supplied to the boiler using the water supply system of ~ 2. As described above, each of the water supply systems A, B, and C includes water supply pumps 51a, 51b, and 51c that can supply the water supply 71 corresponding to 50% of the rated boiler capacity to the boiler. Is provided.

The booster pump inlet valves 61a, 61b, 6
1c are respectively arranged in the middle, one end is connected to the dehydrator storage tank 56, and the other ends are booster pumps 62a, 62b.
b, 62c respectively connected to the deaerator downcomer 60a,
60b, 60c, one ends of which are booster pumps 62a, 62
b, 62c, respectively, and the other end of the water supply pump suction pipes 63a, 63b, 63 connected to the inlets of the water supply pumps 51a, 51b, 51c, respectively.
c, and water supply pump outlet check valves 65a to 65c and water supply pump outlet valves 66a to 66c are respectively disposed in the middle, and one end is connected to the discharge port of each of the water supply pumps 51a, 51b, 51c, and the other end is connected. The feed water pump discharge pipes 64a to 64c respectively connected to the header 67, and the boiler water supply system 5
0, the water supply pumps 51a, 51b, 51c installed in the water supply systems A, B, C are kept in a standby state.
A warming system for warming each is provided. In each of the warming systems, a series connection of warming valves 69a to 69c and orifices 70a to 70c is provided in the middle.
7 and the other end is connected to a water supply pump 51a, 51b, 51.
c is connected to each of the warming tubes 68a, 68
b, 68c.

[0008] In the conventional boiler feedwater pump system configured as described above, when the boiler is switched from the halt state to the operating state, the boiler starts to be started from one arbitrary water supply pump.
Hereinafter, the description will be made assuming that the start is started from the water supply pump 51a. First, the supply water 71 stored in the deaerator storage tank 56 is supplied to the deaerator downcomer 60a, the booster-pump inlet valve 61a, the booster-pump 62a, and the water supply due to the pressure and height difference in the deaerator 55. Pump suction pipe 63a
Through the water supply pump 51a
Warm up. Then, when the difference between the metal temperature of the water supply pump 51a and the temperature of the water supply 71 becomes equal to or less than a certain value,
The water supply pump 51a is started.

After the water supply pump 51a is started in this way, the warming valves 69b and 69c provided in the other water supply systems B and C are opened, and a part of the water discharged from the water supply pump 51a is supplied to the water supply pump 51a. 51b, 51c and feed water pump suction pipes 63b, 63c, booster pumps 62b, 62c and deaerator downcomer pipes 60b, 60.
After c, the boiler feed pumps 51b and 51c are warmed by flowing back and circulating in the deaerator water storage tank 56. After the completion of the warming, the water supply pump 51b or 51c is started in accordance with the operation load of the boiler.

The water supply 71 discharged from the activated water supply pump 51a is caused to flow back to the other water supply systems B and C via warming valves 69b and 69c.
b and 51c, the amount of circulating water to be warmed is very small, but the supply water pumps 51b and 51c which are inactive
Is sufficient to maintain the temperature difference between the temperature of the metal and the temperature of the water supply 71 below a certain value at which the water supply pumps 51b and 51c can be started, and no trouble occurs in the warming of the water supply pumps 51b and 51c.

However, since the amount of circulating water flowing back through the water supply systems B and C is extremely small, the supply water 71 staying in the supply water pump suction pipes 63b and 63c and the deaerator downcomer down pipes 60b and 60c is inactive. However, a problem occurs because it takes a long time to be replaced by the circulating water flow.

That is, when the plant load suddenly decreases, the temperature of the water supply 71 in the deaerator storage tank 56 rapidly decreases, and the pressure also rapidly decreases. On the other hand, the water supply 71 in the water supply pump suction pipes 63b and 63c and the deaeration and downcomer pipes 60b and 60c of the water supply systems B and C, which had been operating at a temperature just before the saturated steam pressure in a high temperature state before the plant load was reduced, was circulated. Because the amount of water is extremely small and the replacement with circulating water is performed only gradually, the high temperature state is maintained,
The pressure drops in the communicating deaerator storage tank 56, so that the pressure drops, so that flushing is performed to generate bubbles. And these air bubbles are supplied to the water supply pump suction pipe 63.
b, 63c and the horizontal portion of the deaerator downcomer 60b, 60c.

Thereafter, when a part of the air bubbles stored in the horizontal portion rises, and when the supply water whose temperature has decreased due to a decrease in the plant load in the deaerator storage tank 56 flows into the portion where the air bubbles have escaped, When a large number of bubbles around the portion from which the bubbles have been removed are quickly cooled and disappear, and a gap is formed in this portion, the water supply 71 in the deaerator storage tank 56 flows in abruptly to generate a water hammer. The problem described above occurs.

Further, there is a problem that bubbles generated by depressurizing flushing of the high-temperature feed water 71 stagnating in the feed water pump suction pipes 63b and 63 and the deaerator downcomer pipes 60b and 60c cause cavitation.

As a method for solving the above-mentioned problem, the diameters of the orifices 70a to 70c installed in the warming system are increased to increase the amount of circulating water flowing backward in the stopped and standby water supply systems B and C. It is possible. According to this method, the water supply pump suction pipes 63b, 63
The high-temperature water 71 stagnating in the c and the deaerator downcomers 60b, 60c is replaced in a short time by the low-temperature water 71 discharged from the water supply pump 51a, thereby solving the above-mentioned problem. Can. However, when such a method is adopted, a large amount of the water supply 71 is always circulated for warming, and the water supply pump 5
A problem that increases the power loss of the motor 1a is newly generated.

[0016]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned disadvantages of the conventional water supply pump warming-up method. Among the water supply systems provided in a plurality of systems, a line of a water supply system in a standby state is provided. Without flushing the water supply inside
Further, it is an object of the present invention to provide a water supply pump warm-up method in which a water supply pump installed in a water supply system in a standby state can be warmed without increasing a power loss of a water supply pump for circulating water to be warmed. As an issue.

[0017]

Therefore, the water pump warm-up method of the present invention employs the following means.

(1) Warming a water supply pump interposed in each of a plurality of water supply systems for supplying water supplied to a boiler from a deaerator and stored in a deaerator storage tank. In order to do so, the feedwater supplied from the feedwater heater to the deaerator is branched, supplied via a warming system attached to each feedwater pump to the feedwater pump as heated feedwater, and stopped. A step of warming the water supply pump so that the difference between the temperature of the water supply pump casing which is low and the temperature of the water supply is within a certain value that does not hinder the activation of the water supply pump.

The feed water branched as the heating feed water may be extracted from an appropriate stage of the feed water heater.
The main valve provided in the feed water heater for branching the feed water may be opened and closed manually, or a temperature switch may be attached to the bleed system of the feed water heater and provided in the warming system. The mining valve may be a temperature control valve, and the temperature of the feedwater stagnating in the feedwater pump suction pipe and the deaerator downcomer pipe may be automatically maintained at an appropriate temperature. Further, it is desirable that the difference between the casing temperature and the supply water temperature be within ○ degrees when warming the water supply pump.

(2) The heating water supplied from the water supply pump is cooled by warming the water supply pump, and the heated water supplied from the water supply pump is deaerated by the deaerator to warm the supply water stored in the deaerator storage tank. Backflow through the deaerator downcomer and the water supply pump suction pipe provided in the water supply system with the water supply pump interposed is performed, and the high temperature state is maintained depending on the load fluctuation. Replacing the feedwater staying in the feedwater pump suction pipe and the deaerator downcomer pipe with cooled heated feedwater to lower the temperature to a temperature lower than a specified temperature at which flushing does not occur.

According to the method for warming up the water supply pump of the present invention, by adopting the above-mentioned steps (1) and (2), water is drawn from the water supply heater outlet of a suitable paragraph as heating water for heating the water supply pump. And heat exchange while supplying water from a warming system. Further, the water supply in the deaerator downcomer and the water supply pump suction pipe further replaces the water supply with a somewhat lower temperature by heat exchange.

(A) Thereby, the feed water pump can be started immediately and warmed to a temperature at which a standby state in which feed water can be supplied to the boiler can be maintained according to the load of the boiler, and the feed water pump suction pipe and the deaerator The feedwater stagnating in the pipe is maintained at an appropriate temperature without becoming hot water, and does not cause flushing even when the plant load suddenly decreases, and may induce water hammer and cavitation accompanying it. Disappears. In addition, it is not necessary to lay new pipes necessary for replacement for supplying water without causing flushing.

(B) Further, the feed water supplied to the feed water pump as the heating feed water is not discharged from the active feed water pump, but the feed water supplied from the feed water heater to the deaerator is branched, in other words. Since the water is discharged from the condensate pump, the diameter of the orifice installed in the warming system is increased to quickly replace the stagnant water in the water supply pump suction pipe and deaerator downcomer pipe. Even if it does, power loss hardly occurs. However, power loss of the condensing pump occurs.

(C) Further, the feedwater branched from the feedwater heater outlet only moves in the feedwater replenishing device and the boiler feedwater device and is not consumed.

The warming method of the water supply pump according to the present invention employs the following means. (3) Provided for supplying water to water supply pumps respectively interposed in a water supply system including a plurality of systems for supplying water supplied to the boiler from the deaerator and stored in the deaerator storage tank. When the temperature of the feedwater in the suction pipe of the feedwater pump becomes higher than the specified temperature, the warming valve provided in the warming system attached to each feedwater pump for warming is closed to warm up. A step of stopping the supply of heated supply water from the system to the supply pump to prevent the supply water from being heated and flushed.

(4) The temperature of the water supply in the water supply pump suction pipe is lower than a specified temperature at which flushing does not occur, and
When the casing temperature of the water pump is low and the temperature is lower than the warm-up temperature, which is lower than the water supply temperature by a certain value, the warming valve is opened and heated water is supplied from the warming system to the water supply pump. Then, a step of warming the water supply pump so that the difference between the casing temperature of the water supply pump and the water supply temperature is within a certain value that does not hinder the operation of the water supply pump.

The opening and closing of the warming valve may be performed manually. However, a temperature switch is attached to the water supply pump suction pipe and the water supply pump casing, and automatic control is performed by using the warming valve as a temperature control valve. Is preferable. Further, the balance point of the opening and closing operation of the warming valve is naturally found depending on the scale of the water supply pump device. Further, the heating water supply from the warming system to the water supply pump is performed as in the step (1) described above.
Water supply branched from the outlet of the water supply heater may be used, or water supplied from an operating water supply pump may be used in the same manner as in the conventional water supply pump warm-up method.

In the water supply pump warming method of the present invention, a thermometer or a temperature switch is attached to the water supply pump suction pipe and the water supply pump casing by adopting the above-mentioned steps (3) and (4), and the temperatures of both of them are measured. By measuring the temperature signal and operating the warming valve of the warming pipe based on these temperature signals, the water supply pump can be warmed without causing a problem due to flushing of the water supply.

That is, when the measured temperature of the feedwater staying in the feedwater pump suction pipe becomes equal to or higher than the temperature at which flushing is caused, the warming valve is closed to stop the warming of the feedwater pump. When the temperature of the casing is not sufficient to start the water supply pump, and the temperature of the water remaining in the water supply pump suction pipe of the water supply pump is lower than the temperature at which flushing is caused, the warming is performed. By opening the mining valve and supplying heated water to the water supply pump to raise the temperature of the water supply pump casing to a temperature at which the water supply pump can be started, the same operation and effect as in the above (a) can be obtained. In addition, it is possible to solve the problem caused by the conventional water supply pump warm-up method.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a feed water pump warm-up method according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a boiler feed pump system for showing a first embodiment of a feed pump warm-up method of the present invention.
In the drawing, the same members as those shown in FIG. 3 are denoted by the same reference numerals, and detailed description is omitted.

The steam that drives the turbine not shown is
The exhaust gas returns to the condenser 52, where it is cooled and condensed, and is stored in the condenser 57. The condensate in the condenser 52 is drawn out by a condensate pump 53, is heated by a feed water heater 54 through a condensate pipe 53, enters a deaerator 55, and is heated by steam supplied from a steam pipe 59. It is heated and degassed and stored in the deaerator storage tank 56.

The water stored in the deaerator water storage tank 56 is supplied to the water supply systems A,
Deaerator downcomers 60a, 60b, 60c forming B and C
Is supplied to the boiler water supply device 50 within the two-dot chain line. In addition, a suffix a is attached to a device attached to the water supply system A or a water supply pump warming system A described later, and a suffix b is attached to a device attached to the system B.
The suffix c is added to the device attached to the system C.

The water supply systems A, B and C are provided with booster pump inlet valves 61a, 61b and 61c and a booster pump 6 in addition to the deaerator downcomers 60a, 60b and 60c described above.
2a, 62b, 62c, feed water pump suction pipes 63a, 63
b, 63c, water supply pumps 51a, 51b, 51c, water supply pump discharge pipes 64a, 64b, 64c, water supply pump outlet check valves 65a, 65b, 65c, water supply pump outlet valve 66
a, 66b, 66c are connected in series, and the water supply pump outlet valves 66a, 66b, 66c are connected to the header 67.
To supply water 71 in the deaerator storage tank 56 to the boiler.

In such a boiler feed pump system, in this embodiment, feed pumps 51a, 51b, 51
As the heating water supply for warming c, the water supply 71 from the water supply heater 54 in an appropriate paragraph was extracted and used. For this purpose, the water supply pumps 51a, 51b,
Warming pipes 68a, 68 provided for warming the 51c and constituting the boiler water supply device 50.
b, 68c The water supply pump warming systems 72a, 72b, 72c, which communicate with the warming valves 69a, 69b, 69c and the orifices 70a, 70b, 70c, and the water supply heater 54 are connected by the extraction pipe 1. I have.

The extracted water extracted from the feed water heater 54 is supplied to the feed water pump warming systems 72a, 72b, 72c.
, And all or any of the water supply pumps 51a, 51b, and 51c that need to be warmed up and are in a standby state are warmed up. Further, the heated water supplied by warming the water supply pumps 51a, 51b, 51c and exchanging heat becomes low in the deaerator water through the water supply pump suction pipes 63a, 63b, 63c and the deaerator downcomer pipes 60a, 60b, 60c. Tank 56
Backflow to Due to this backflow, the deaerator downcomer 60
a, 60b, 60c and feed pump suction pipes 63a, 6
The stagnant water in 3b and 63c is quickly replaced with heated and supplied water that is cooled and cooled to a low temperature, and is maintained at a low temperature.

As described above, by employing the water supply pump warm-up method of the present embodiment, the water supply pumps 51a, 51b, 51
c, when none of them is operating, it can be started immediately and warmed to a temperature that can maintain the standby state in which the water supply 71 can be supplied to the boiler according to the load of the boiler, and the water supply pumps 51a, 51b, The feedwater 71 stagnated in any of the feedwater pump suction pipes 63a, 63b, 63c and the deaerator downcomer pipes 60a, 60b, 60c connected to 51c is maintained at an appropriate temperature without becoming hot water.
The plant load suddenly changed, and the water supply in the deaerator storage tank 7
Even if the temperature and pressure of 1 suddenly decrease, the supply water 71 stagnating in the pipe does not cause flushing, and does not induce water hammer and cavitation associated therewith.

Further, it is not necessary to lay a new pipe necessary for replacing the staying water for supplying the water 71 without causing flushing. In addition, the water supply 71 supplied to any of the water supply pumps 51a, 51b, and 51c that are in a standby state as the heating water supply is replaced with the water supply pump 51 that is operating.
a, 51b, and 51c, the water supplied from the water heater 54 to the deaerator 55
1 is used, the orifice diameters 70a, 70b, 70c installed in the warming systems 72a, 72b, 72c are increased.
The water supply pump suction pipe 63 of the water supply system in the standby state
a, 63b, 63c and deaerator downcomer 60a, 60
Regardless of how quickly the water 71 stagnated in any of b and 60c is replaced, power loss hardly occurs. However, power loss of the condensing pump occurs.

Further, the feed water 71 branched from the outlet of the feed water heater 54 only moves in the feed water replenishing device 49 and the boiler feed device 50, and is not consumed and does not cause a problem associated with an increase in make-up water. Further, in order to make the feed water supplied from the feed water heater 54 to the deaerator 55 into heating feed water, the opening and closing of a main valve provided in the feed water heater 54 is performed by attaching a temperature switch to the extraction system of the feed water heater 54, Ming valve 69
a, 69b, 69c are temperature control valves, and the water supply pump suction pipe 6
3a, 63b, 63c and deaerator downcomer 60a, 60
If the temperature of the feed water 71 stagnating in the b and 60c can be controlled to be automatically maintained at an appropriate temperature, the plant efficiency can be further improved.

Next, FIG. 2 is a diagram showing a system of a boiler water supply apparatus for showing a second embodiment of the water supply pump warm-up method of the present invention.

As shown in the drawing, the water supply systems A, B, and C constituting the water supply pump device 50 are all connected to the deaerator downcomer 60.
a, 60b, 60c, booster pump inlet valve 61a,
61b, 61c, booster pumps 62a, 62b, 6
2c, water supply pump suction pipes 63a, 63b, 63c, water supply pumps 51a, 51b, 51c, water supply pump discharge pipe 64
a, 64b, 64c, feed water pump outlet check valve 65a, 6
5b, 65c, and feed water pump outlet valves 66a, 66
b and 66c are connected to communicate with the header 67,
Warming pipes 68a, 68b, 68c and warming source valves 69a, 6 are provided between the header 67 and the water supply pump 51.
9b, 69c and orifices 70a, 70b, 70c
Are connected in series, and the feed water pump warming system 72a,
72b and 72c are formed.

In the conventional boiler water supply device 50 configured as described above, the water supply pump suction pipes 63a, 63b, 6
3c and the casings of the water supply pumps 51a, 51b, 51c are provided with thermometers or temperature switches 2, respectively, and both thermometers or temperature switches 71 are provided.
The temperature is measured, and the feed water pump 51
a, 51b, and 51c are warmed, and the temperatures in the deaerator downcomer pipes 60a, 60b, and 60c and the feed water pump suction pipes 63a, 63b, and 63c are maintained at low temperatures.

That is, the measured water supply pump suction pipe 6
When the temperature of the feed water 71 staying in the 3a, 63b, 63c becomes higher than the temperature causing flushing, the warming valves 69a, 69b, 69c are closed, and the warming of the feed water pumps 51a, 51b, 51c is started. Stops and prevents the occurrence of problems due to the occurrence of flushing.

The water supply pumps 51a, 51b, 51c
The temperature of the casing of the water supply pumps 51a, 51b, 51
The temperature of the feed water 71 that has not reached a sufficient temperature for starting the water supply pump 51a, 51b, and 51c and that is retained in the feed water pump suction pipes 63a, 63b, and 63c, respectively. When the temperature is lower than the temperature at which the flushing is caused, the warming valves 69a, 69
9b and 69c are opened, the water is supplied from any of the water supply pumps 51a, 51b and 51c operating the heating water supply, and the water supply pumps 51a, 51b and
By raising the casing temperature of the casing 51c to a temperature at which it can be started, the casing is placed in a standby state as in the first embodiment,
Any of the water supply pumps 51a, 51b, and 51c that are not operating can warm immediately to a temperature at which a standby state in which the water supply 71 can be supplied to the boiler can be maintained according to the load of the boiler.

Further, the water supply pump suction pipes 63a, 63
b, 63c and the supply water 71 staying in any of the deaerator downcomer 60a, 60b, 60c are maintained at an appropriate temperature,
Even if the plant load is suddenly reduced, no flashing is caused, and no water hammer and cavitation are caused. In addition, there is provided an advantage that it is not necessary to lay a new pipe for replacing the stagnant water in order to supply the water 71 without causing flushing.

That is, the water supply pump suction pipes 63a, 63
If the temperature of the water supply 71 in b, 63c is higher than the specified temperature, the warming valves 69a, 69b, 69c are closed,
Water supply 71 in water supply pump suction pipes 63a, 63b, 63c
If the temperature is lower than the specified temperature and the feed water pump casing temperature is lower than the warm-up temperature, the operation of opening the warming source valve 69 is performed, and the feed water pump casing temperature is set to the warm-up temperature, and deaeration is performed. The temperature in the downcomer 60 and the feed pump suction pipe 63 is maintained at a low temperature.

Further, this temperature operation, that is, opening and closing of the warming valves 69a, 69b, 69c is performed by manual operation of a thermometer visually or by a water supply pump suction pipe 63a, 63b,
If the temperature switch 2 is mounted on the water supply pump casing 63c and the water supply pump casing, and the warming valves 69a, 69b, and 69c are used as temperature control valves to perform automatic control, higher reliability can be achieved. In the present embodiment, a part of the water supply 71 discharged from the operating water supply pumps 51a, 51b, 51c is supplied to the water supply pumps 51a, 51b, 51c in a standby state as heating water supply. However, as in the first embodiment, the feed water heater 5
The water supply 71 supplied from 4 to the deaerator 55 may be branched and used as heating water supply.

[0047]

As described above, according to the feed water pump warming method of the present invention, the feed water supplied from the feed water heater to the deaerator is branched and heated to the feed water pump via the warming system. Supplying the water as a water supply, and warming the water supply pump; heating water cooled by the warming of the water supply pump is caused to flow back into the deaerator storage tank through the water supply pump suction pipe and the deaerator downcomer, thereby supplying the water supply pump; By adopting a process to reduce the temperature of the water supply in the suction pipe and deaerator downcomer to a specified temperature or less, it is suitable for warming of the water supply pump from the water supply heater, and flushing occurs in the deaerator downcomer and water supply pump suction pipe. It is possible to continuously supply water at a suitable temperature, and it is not necessary to lay new pipes for hot water replacement.

As a result, even when the plant load is suddenly reduced, the supply water in the deaerator downpipe and the supply pump suction pipe is subjected to depressurized flushing and does not generate water hammer or cavitation.

Further, according to the feed water pump warm-up method of the present invention, when the temperature of the feed water in the feed water pump suction pipe becomes higher than the specified temperature, the warming valve is closed to switch the warming system to the feed water pump. A step of stopping the supply of the heating water, and when the temperature of the water supply in the water supply pump suction pipe is lower than the specified temperature, and when the temperature of the casing of the water supply pump is lower than the warm-up temperature, the warming valve is opened and the warming system is opened. By supplying the heating water supply to the water supply pump and adopting the step of warming the water supply pump, the temperature of the water supply water staying in the water supply pump suction pipe,
When the temperature exceeds the specified temperature that causes flushing, close the warming valve and stop warming of the water supply pump.
Further, the temperature of the water supply pump casing has not become a warm-up temperature sufficient for starting the water supply pump, and the temperature of the water remaining in the water supply pump suction pipe of the water supply pump has fallen below the specified temperature causing flushing. When the plant load is suddenly reduced by opening the warming valve and supplying the heating water to the water supply pump and raising the temperature of the water supply pump casing to a temperature at which the water supply pump can be started, The water supply in the deaerator downpipe and the water supply pump suction pipe is depressurized and flushed, and the water supply pump can be kept in a standby state in which the water supply pump can be immediately started without generating water hammer or cavitation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a boiler feed pump system for showing a first embodiment of a feed water pump warm-up method of the present invention,

FIG. 2 is a diagram showing a system of a boiler water supply apparatus for illustrating a second embodiment of the water supply pump warm-up method of the present invention,

FIG. 3 is a diagram showing a conventional boiler feedwater pump system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extraction pipe 2 Thermometer or temperature switch 49 Water supply replenishment apparatus 50 Boiler water supply apparatus 51a, 51b, 51c Water supply pump 52 Condenser 53 Condensation pump 54 Feedwater heater 55 Deaerator 56 Deaerator storage tank 57 Condenser pipe 58 Check valve 59 Steam pipe 60a, 60b, 60c Deaerator downcomer pipe 61a, 61b, 61c Booster pump inlet valve 62a, 62b, 62c Booster pump 63a, 63b, 63c Water supply pump suction pipe 64a, 64b, 64c Water supply pump discharge pipe 65a, 65b, 65c Water supply pump outlet check valve 66a, 66b, 66c Water supply pump outlet valve 67 Heading 68a, 68b, 68c Warming tube 69a, 69b, 69c Warming valve 70a, 70b, 70c Orifice 71 Water supply 72a, 72b , 72c Water supply pump warmin System A, B, C Water System

Claims (2)

[Claims] 1. A deaerator downcomer, a water supply pump suction pipe and a water supply pump discharge provided in a plurality of systems for supplying water supplied to a boiler, which is deaerated by a deaerator and stored in a deaerator storage tank. A water supply pump which is interposed in a water supply system composed of a pipe and a warming system composed of a warming pipe and a warming valve is provided for each,
In a water supply pump warming method configured to warm with heating water supply, the water supply supplied to the deaerator from a water supply heater is branched and supplied to the water supply pump as the heating water supply through the warming system. And warming the feedwater pump, and causing the heated feedwater cooled by the warming of the feedwater pump to flow back into the deaerator storage tank via the feedwater pump suction pipe and the deaerator downcomer. Cooling the feedwater staying in the feedwater pump suction pipe and the deaerator downcomer to a specified temperature or lower. 2. A deaerator downcomer, a water supply pump suction pipe and a water supply pump discharge provided in a plurality of systems for supplying water supplied to the boiler, which is deaerated by the deaerator and stored in the deaerator water storage tank. A water supply pump which is interposed in a water supply system composed of a pipe and a warming system composed of a warming pipe and a warming valve is provided for each,
In the water supply pump warming method configured to warm with heated water supply, when the temperature of the water supply in the water supply pump suction pipe becomes higher than a specified temperature, the warming valve is closed, and the warming system is closed. Stopping the supply of the heated water supply to the water supply pump; and when the temperature of the water supply in the water supply pump suction pipe is lower than a prescribed temperature, and when the casing temperature of the water supply pump is lower than the warm-up temperature, the warming valve is provided. And supplying the heating water from the warming system to the water supply pump, and warming the water supply pump.