JPH02267403A - Control of feed water of condensate - Google Patents

Abstract

PURPOSE:To secure suction pressure required for a condensate pump and a feed water pump and make it possible to provide stable and continuous water supply by detecting the state of operation of the system of heater draining system and judging whether or not automatic tripping motion of the condensate pump and feed water pump is required. CONSTITUTION:In a steam power plant is which condensate feed water mean are provided with two sets of condensate pumps 10, high pressure condensate pumps 12 and feed water pumps 15 arranged in parallel respectively and the heater drain system is provided with a high pressure drain pump 21 and low pressure drain pump 26 the condensate system and the feed water system are provided with a trip detection signal generator 40 for the condensate and the feed water pump, and the heater drain system is provided with a detector 43 for the state of operation of the heater drain system. And at the time of trip of the condensate pump and feed water pump it is judged whether or not trip is required for the condensate pump and feed water pump on the downstream side of the tripped pumps by the signal from the detector 43 for the state of operation of the heater drain system, and during the operation of the heater drain system only automatic starting of a spare machine is made and during it is stopped, the pumps for the condensate system and the feed system water on the downstream side are tripped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a condensate water supply system for a power plant, and particularly to a condensate water supply control method for supplying stable water supply to a steam generator.

[Conventional technology]

Regarding the water supply system to the conventional steam generator, see Japanese Patent Application Laid-open No. 1986-
No. 105495, and the problems of the conventional method will be explained with reference to FIG.

The steam generated in the steam generator 1 passes through the main steam 2 flow meter 2 and the steam generator outlet valve 29, enters the high pressure turbine 5 to perform work, passes through the cross-around pipe 6° moisture separator 7, and is transferred to the low pressure It is supplied to the turbine 8 and rotates the turbine.

Steam exhausted from the turbine is condensed in a condenser 9 and becomes condensate. The condensate is transferred to a condensate pump 10, a condensate purification device 1
1, high pressure condensate pump 12, low pressure feed water heater 13, 14,
The water is returned to the steam generator 1 through a feedwater pump 15 and a high-pressure feedwater heater 16. On the other hand, the steam extracted from the middle of the turbine exchanges heat with the feed water in the feed water heater and becomes a drain. The high-pressure drain is collected in a high-pressure drain tank 21, increased in pressure by a high-pressure drain pump 22, and directly collected at the water supply pump inlet via a high-pressure drain tank water level adjustment valve 23.

Further, the low-pressure drain is collected in the low-pressure drain tank 25, raised in pressure by the low-level drain pump 26, and directly collected at the inlet of the high-pressure condensate pump 12 via the low-pressure drain tank water level adjustment valve 27.

[Problem to be solved by the invention]

Here, the water supply flow rate to the steam generator 1 is determined by the steam generator water level detector 18 so that the water supply water level in the steam generator 1 is constant.
The feed water flow rate itself is controlled by the feed water control device 28 based on the measured values of the main steam flow meter 2 and the feed water flow meter 17. Changes in the feed water flow rate itself are controlled by adjusting the rotation speed of the feed water pump 15 by a request signal from the feed water control device 28. Do by doing. In the condensate water supply system of the above conventional technology, as shown in Fig. 2, when the condensate water supply system pump (low pressure condensate pump, high pressure condensate pump) trips, the low pressure condensate pump or high pressure condensate pump is activated. Since only one unit is operated, the suction pressure of the water supply pump decreases, and in order to prevent all the water pumps from stopping, an interlock is installed to automatically trip the downstream condensate water supply system pump and start it again. . However, the reliability of the plant decreases because the downstream condensate water supply pump is automatically tripped and restarted. (There is a possibility of restart failure) In addition, in a power generation plant with one water pump backup machine (25%), even if the backup machine automatically starts normally, the generator output will be reduced to about 75%. need to be lowered.

The purpose of the present invention is to provide a condensate water supply system pump (low pressure condensate pump,
By controlling the operation status of the heater drain system or the amount recovered from the heater drain system when the high-pressure condensate pump, water supply pump) trips, the required suction pressure of the condensate water supply system pump is ensured and a stable continuous water supply is achieved. It's about trying.

[Means to solve aM]

The feature of the present invention is to detect the operating state of the heater drain system,
The objective is to determine whether automatic trip operation of the condensate water supply system pump is necessary.

[Effect]

In a power generation plant that recovers heater drain to the condensate system, as shown in Figure 5, in order to recover heater drain equivalent to approximately 45% of the feed water flow rate into the condensate system, the required suction pressure of the pump for the condensate water supply system pump trip is Less impact.

Furthermore, when the condensate water supply system pump trips, the pressure at the drain recovery point decreases, so the heater drain pump runs out and the amount of recovered water to the condensate system increases. In this way, the necessary suction pressure of the condensate water supply system pump is relieved when the condensate water supply system pump trips. Furthermore, by controlling the drain tank water level control valve of the heater drain system using the condensate water supply system pump trip signal, it is possible to increase the amount of collected water to the condensate system, thereby providing stable suction pressure to the condensate water supply system pump. can be ensured. Additionally, if the heater drain pump runs out, the water level in the heater drain tank may drop and the drain pump may trip, but the signal from the drain tank water level detector installed in the heater drain tank (usually Set the water level to return the drain system control to normal control between the water level and the drain pump trip water level) or a timer (set a timer to return the drain system control to normal control a few seconds after the condensate water supply system pump trip) By using the above, short-term (several seconds) run-outs can be controlled (operated) without any problems.

〔Example〕

The present invention is generally applicable to devices that recover feedwater heater drain directly into a condensate system.

An example thereof is shown in FIGS. 1 and 2. The steam generated from the steam generator 1 is passed through the main steam flow meter 2. Steam generator outlet valve 2
9, enters the high pressure turbine 5 to perform work, and passes through the cross-around pipe 6. The water is supplied to a low pressure turbine 8 through a moisture separator 7 and rotates the turbine. Steam exhausted from the turbine is condensed in a condenser 9 and becomes condensate. The condensate is supplied by a condensate pump 10, a condensate purifier 11, a high pressure condensate pump 12, a low pressure feed water heater 13, 14, a feed water pump 15,
It is returned to the steam generator 1 through a high pressure feedwater heater 16.

On the other hand, the steam extracted from the middle of the turbine exchanges heat with the feed water in the feed water heater and becomes drain. The high-pressure drain is collected in a high-pressure drain tank 21, increased in pressure by the high-pressure drain pump 21, and directly collected at the water supply pump inlet via the high-pressure drain tank water level adjustment valve 23. Further, the low pressure drain is collected in a low pressure drain tank 25, and the pressure is increased by a low pressure drain pump 26, and a low pressure drain tank water level adjustment valve 27 is used.
directly to the inlet of the high-pressure condensate pump 12.

Here, the flow rate of the water supply to the steam generator 1 is determined by the steam generator water level detector 1 so that the water level of the water supply in the steam generator 1 is constant.
8, the main steam flowmeter 2, and the feedwater flowmeter 17, the water supply control device 28 controls the flow rate. Changes in the water supply flow rate itself can be made by changing the rotation speed of the water supply pump 15 to the water supply control device 28.
This is done by adjusting according to the request signal from.

In this condensate water supply system, a trip detection signal generator 40 of the condensate water supply pump and a heater drain system operating state detection device 43 are used.
As shown in Fig. 4, the necessity of tripping the downstream condensate water supply system pump is determined based on the signal from the heater drain system operating state detection device 43, and while the heater drain system is operating, the standby equipment is automatically activated. It only starts up, and when the heater drain system is stopped, the downstream condensate water supply system pump is tripped.

Generally, the heater drain pump is operated at a load of 50% or more, so the electrical output is ensured before the condensate water supply system pump trips. In addition, the heater drain amount is 3 of the rated water supply flow rate.
However, by sending an excessive flow rate with the drain pump, approximately 40% of the drain (runout flow rate is 125% of the pump specification point flow rate) can be recovered to the condensate system.

In other words, the drain flow rate control device [41, 42] consisting of the heater drain flow rate detector 30, 31, drain tank water level detector 24, 34, etc. sets the runout flow rate to 125% of the pump specification point flow rate as the maximum flow rate for pump protection. can be restricted. In addition, if the drain pump runs out, the water level in the drain tank will drop, but the drain tank water level detector 24° 34 (usually detects the water level between the tank water level and the drain pump trip level to return the drain system control to normal control) By restoring the drain system to normal control using a signal from the condensate water supply system (setting) and a timer (a timer is provided to return the drain system control to normal control a few seconds after the condensate water supply system pump trips), the drain pump trip level is reached. The drain tank water level will not drop.

Therefore, runout of the condensate water supply system pump can be reduced, so when the condensate water supply system pump trips, the downstream condensate water supply system pump will not be tripped, and the required suction pressure of the condensate water supply system pump can be secured.

FIG. 3 shows another embodiment of the invention. In the condensate water supply system, a condensate water supply system trip signal generator 40 and drain tank water level control valve bypass valves 32 and 33 are installed, and when the condensate water supply system pump trips, the condensate water supply system The signal from the trip signal generator 40 and the drain tank water level detectors 24, 34 control the drain tank water level control valve bypass valves 32, 33 to cause the drain pump to run out. This makes it possible to maximize the performance of the drain pump and minimize run-out of the condensate water supply system pump.

As the amount recovered from the heater drain system increases, the amount of condensate sent from the low-pressure condensate pump and high-pressure condensate pump decreases, so the pumping height of the low-pressure condensate pump and high-pressure condensate pump increases, and the condensate water supply system Pump suction pressure increases. In addition, the drain tank water level control valve bypass valve 32, 3
3 opens, the water level in the drain tank will drop, but the drain tank water level detector 24.34 (usually sets the water level between the tank water level and the drain pump trip level to return the drain system control to normal control) Alternatively, since a timer is provided to return the drain system control to normal control several seconds after a condensate water supply system pump trip, the water level will not drop to the drain pump trip level.

[Brief explanation of drawings]

Figures 1 and 2 are system diagrams of one embodiment of the present invention, Figure 3 is a system diagram of another embodiment of the present invention, Figure 4 is a determination flowchart of the present invention, and Figure 5 is a condensate water supply. An explanatory diagram of system-drain system flow balance, FIG. 6 is a system diagram of a conventional condensate water supply system, and FIG. 7 is a conventional determination flowchart. 1...Steam generator, 2...Main steam flow meter, 3...
Main steam pipe, 5... High pressure turbine, 7... Moisture separator, 8... Low pressure turbine, 9... Condenser. Agent: Patent attorney Katsuo Ogawa fTx No. [Effects of the Invention] According to the present invention, the necessary population pressure of the water supply pump can be ensured when the condensate water supply system pump trips, etc., and a stable water supply can be supplied to the steam generator. 1-RFP---9111 Horse Emla Mizufu〉fu.

Claims (1)

[Claims] 1. A plurality of condensate pumps that supply water from a condenser of a power generation plant to a steam generator, a plurality of water supply pumps that are installed downstream of the condensation pumps, and a water supply that heats the feed water. a heater,
In a condensate water supply system and a heater drain system that are comprised of a drain pump that directly collects drain from the feedwater heater into the water supply system and piping that connects them, when the condensate pump or the water supply pump trips. A condensate water supply control method, characterized in that it is determined whether to continue operating or automatically stop the tripped condensate pump or a pump downstream of the water supply pump, using the operating state of the drain pump as a determination condition. 2. A plurality of condensate pumps that supply water from a condenser to a steam generator in a power generation plant, a plurality of water supply pumps that are installed downstream of the condensate pumps, and a feed water heater that heats the feed water;
In a condensate water supply system and a heater drain system, which are comprised of a drain pump that directly collects drain from the feedwater heater into the water supply system and piping that connects them, when the condensate pump or the water supply pump trips; ,
A condensate water supply control method characterized by controlling the amount of water recovered from a heater drain system. 3. The condenser according to claim 2, wherein a water level control valve of a drain tank is controlled by a signal from a trip detection signal generator of the condensate pump or the water supply pump, and the drain pump supplies water at an excessive flow rate. Water supply control method. 4. In claim 2, a bypass valve is provided in the trip detection signal generator and the drain tank water level control valve, and the signal from the trip detection signal generator and the drain tank water level detector is used to A condensate water supply control method comprising controlling the bypass valve of a drain tank water level control valve.