JPS5827210Y2 - Heater drain water level control device for steam power generation equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a heater drain water level control device for steam power generation equipment that controls the drain water level of a feed water heater (hereinafter referred to as a heater) in steam power generation equipment.

Generally, steam such as bleed air from a steam turbine is introduced into the heater, and the feed water is passed through a number of tubes and heat exchanged across the tube walls to raise the temperature of the feed water.

In this case, the heat-exchanged steam becomes drain. In many steam power generation facilities, multi-stage heaters are provided, and the feed water passes through the multi-stage heaters in order to raise its temperature.

Further, each stage heater is supplied with bleed air from a different steam turbine bleed hole.

Furthermore, the drain from the previous stage heater is also introduced into the next stage heater.

The next stage drain is a gradual heater (or open type heater)
It flows out into the hexagram and the capacitor.

The heater is thus connected to the steam turbine through the bleed pipe.

For this reason, in each stage of the heater, the drain water level is controlled by releasing the drain to the next stage heater via the heater drain valve so that the drain water level is normally maintained at a constant normal water level (N, W, L) within the heater.

During load changes in steam power generation equipment, the heater drain water level may temporarily rise.

To cope with such high water levels, a normal bypass valve is often installed to release the condenser hedren.

In other words, even if the drain valve of the next stage heater drain valve is fully opened, if the drain water level rises, the water level α remains constant.
The normal bypass valve opens to release drain to the condenser and control the water level so as to maintain the heater drain water level at the so-called normal bypass water level (N, W, L+α) which exceeds the normal water level (N, W, L) by 1.

In addition, in order to prevent condensate from flowing into the turbine through the bleed pipe even if the heater tube breaks, an emergency relief valve is opened when the heater water level is high to discharge condensate into the condenser. Provide equipment.

Heater drain water level control that combines a normal control device with such a drain discharge to the heater and a normal bypass, and an emergency control device with an emergency relief valve satisfies each purpose.

However, if a failure occurs in the water level detector, etc. of the normal control device, even if only the emergency control device operates, it will not be possible to discharge the amount of drain that would be discharged by the normal control device, causing the heater drain water level to rise. However, there is a risk that the air will flow backwards through the bleed pipe and into the turbine, leading to serious failure.

This will be explained below with reference to an example of a conventional heater drain water level control device shown in FIG.

Steam turbine bleed air and pre-stage drain flow into the heater 1, which exchanges heat with the feed water within the heater 1 and becomes drain.

The normal control device for the heater drain water level is a next stage consisting of a drive controller 4 for driving a heater drain valve 3 for discharging the next stage heater 2, a control water level setter 5, an actual water level detector 6 for the heater 1, and a water level oscillator 7. There is heater drain water level control by draining drain to the heater 2.

In addition, the normal control device includes a controller 10 that drives a normal bypass valve 9 for discharging the condenser 8.
Heater drain water level control is often added by draining drain to the capacitor 8, which is composed of the water level setter 11, the heater actual water level detector 6, and the water level transmitter I described above.

In this case, the water level setter 5 is set to the normal water level (N, W, L), and the water level setter 11 is set to a higher water level than the normal water level (N, W, L+α), so the normal bypass valve 9 is A backup operation is performed that starts opening after the heater drain valve 3 is fully opened.

Next, the emergency control device is composed of a drive controller 13 that drives the emergency relief valve 12, a water level setting device 14, a heater actual water level detector 15, and a water level transmitter 16. 16 integrated devices may also be used.

This emergency control device is intended to prevent the water level of the heater drain from rising rapidly due to the jetting out of the supply water due to the breakage of the heater tube, and to prevent the turbine hedren from flowing in through the bleed pipe.

Therefore, when the water level of the heater drain rises in the water level housing which further exceeds the water level set value of the normal bypass valve 9, the emergency relief valve 12 is opened to release the drain to the condenser 8, and is operated to suppress the rise in the water level of the heater drain.

The emergency relief valve 12 starts to open after the heater drain valve 3 and normal bypass valve 9 are fully opened.

Here, regarding the capacity of the heater drain valve 3, the capacities of the heater drain valve 3 and the normal bypass valve 9 are set so that normal control can be performed in consideration of the increase in the amount of drain corresponding to the output of the power generation plant, as shown in Fig. 2. In the event of an abnormality in which the heater tubes break, the capacity A of the emergency relief valve 12 is determined so that the number of broken tubes can be minimized and the increased drain capacity can be discharged in the event of an abnormality.

Generally, as shown in FIG. 3, the capacity A of the emergency relief valve 12 is much smaller than the capacity B of the heater train valve 3 or the normal bypass valve 9.

Therefore, in the conventional device, when the normal control device, for example, the water level detector 6 or the water level transmitter 1 fails, and the heater drain valve 3 and the normal bypass valve 9 are both fully closed (11), the drain discharge capacity is the emergency relief valve 12. capacity only.

This usually results in a lack of drain discharge capacity due to a failure of the control device, and there is a risk that the heater drain water level will rise sharply and that water will flow into the turbine.

This idea was made in consideration of these circumstances,
Heater drain water level for steam power generation equipment When the heater drain water level rises due to a failure of the normal control device and the emergency control device is activated, the drain discharge valve of the fuel device is usually opened to discharge the drain and the sudden rise in the heater water level can be suppressed. Heater drain water level for steam power generation equipment The purpose is to provide a control device.

Hereinafter, a seven-day embodiment of this invention will be described with reference to FIG. 4. Parts that are the same as those in FIG. 1 are given the same reference numerals, and their explanation will be omitted, and points different from FIG. 1 will be explained.

In other words, when the emergency control device is activated, this invented device
Normally the heater discharge valve of the control device or Wachi heater drain valve 3
Focusing on the normal operation order in which the normal bypass valve 9 and the normal bypass valve 9 are fully opened, when the emergency control device is activated, the drain discharge valve and the heater drain valve 3 A linked opening device 17, 18 for opening the normal bypass valve 9 is provided.

The link opening actuating device 17 is provided in a part of the piping through which driving force is applied from the drive controller 4 to the heater drain valve 3, and the driving force of the drive controller 13 is also input to the link opening actuating device 11. It has become.

The link opening actuating device 18 is provided in a part of the piping through which driving force is applied from the drive controller 10 to the normal bypass valve 9, and the driving force from the drive controller 13 is also input to the link opening actuating device 18. It has become so.

With this configuration, even if all or any of the water level detector 6, water level transmitter 7, and drive controllers 4, 10 of the normal control device fails, the water level detector 15 of the emergency control device will detect a high water level. The drive controller 13 detects the high
When activated, the emergency drain valve 12 is activated, and the heater drain valve 3 and normal bypass valve 9 are opened by the simultaneous linked opening actuation device 17,18.

Therefore, there is no shortage of drain discharge capacity as in conventional devices.

This point is clear from the relationship between the failure situation and drain discharge capacity shown in FIG.

Capacitance symbols A and B in FIG. 5 are the same as those in FIG. 3.

That is, in the event of a failure of the normal control device, in the conventional device, the maximum capacity A of only the emergency relief valve 12 would be insufficient for the maximum drain amount B of the plant. No matter which one is used, the maximum capacity will be the sum (A+B) of the capacity A of the emergency relief valve 12 and the capacity B of the normal control valve of either one, resulting in a system with sufficient margin for the maximum drain amount of the plant.

However, this invention is not limited to the above-mentioned embodiment, and may be modified as follows, for example, by using a known opening priority device (high value priority device) as a linked opening actuating device.

Furthermore, even if one of the linked opening actuators 17 and 18 in FIG. 4 is deleted depending on the applied heater drain water level control device, the effect will not change from the relationship between the failure situation and drain discharge capacity shown in FIG. 5. do not have.

In addition, various modifications can be made without changing the gist of the invention.

According to this invention described above, a linked opening device is provided which opens the drain discharge valve of the normal control device by the opening operation of the emergency control device that bypasses the capacitor hedrain. It is possible to provide a heater drain water level control device for steam power generation equipment that can eliminate the risk of a sudden increase in water level and water inflow into the turbine, and therefore improves the reliability of protection against serious failure of the turbine, especially due to water inflow into the turbine.

[Brief explanation of the drawing]

Figure 1 is a configuration explanatory diagram showing an example of a conventional heater drain water level control device, Figure 2 is a diagram showing the relationship between the amount of drain output from a power generation plant in the same example, and Figure 3 is a diagram showing the relationship between the drain valve opening and drain discharge in the same example. FIG. 4 is a diagram illustrating the configuration of an embodiment of the heater drain water level control device according to this invention, and FIG. 5 is a diagram illustrating the effects of the embodiment. 1...Heater, 2...Next stage heater, 3
...Drain valve, 4...Drive controller, 5...Control water level setting device, 6...
・・Actual water level detector, I・・・Water level transmitter, 8,・
... Capacitor, 9 ... Normal bias valve, 10 ... Drive controller, 11 ...
... Water level setting device, 12 ... Emergency relief valve, 13
... Drive controller, 14 ... Water level setter, 15 ... Water level detector, 16 ...
・・Water level oscillator, 11 ・・・Linked opening actuator, 1
8... Linkage opening actuation device.

Claims (1)

[Scope of utility model registration request] In a device that leads the drain in the heater to the next stage heater button and condenser via drain piping, an emergency relief valve provided on the piping on the inlet side of the condenser, and an emergency relief valve installed on the piping on the inlet side of the next stage heater and condenser, respectively. A heater drain valve and a normal bypass valve are provided, a first water level detector detects when the water level in the heater becomes high, and the detected value of the first water level detector is set as the set value of the water level setting device. a first controller that issues an opening command to the emergency relief valve when the water level exceeds the normal water level; a second water level detector that detects the normal water level in the heater; and a detected value of the second water level detector that sets the control water level. a second controller that gives an opening command to the heater drain valve when the set value of the heater drain valve is exceeded;
a third controller that gives an opening command to the normal bypass valve when the detected value of the water level detector exceeds the set value of the water level setting device; A heater drain water level control device for steam power generation equipment, comprising a device that gives an opening command to at least one of a valve and a normal bypass valve.