JP4166467B2 - War tanning prevention device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a water-induction prevention device in a power generation steam turbine plant.
[0002]
[Prior art]
In power generation steam turbine plants, condensers, feed water heaters, and deaerators are important heat exchangers. The condenser condenses the exhaust steam of the steam turbine for power generation and keeps the back pressure of the turbine in a vacuum, increasing the efficiency of the steam turbine plant for power generation and recovering this condensed and condensed water to generate power again. It is installed for the purpose of being used for the steam turbine cycle. The feed water heater is installed for the purpose of improving the thermal efficiency of the power generation steam turbine plant by heating the condensate and the feed water using the extraction of the power generation steam turbine. The purpose of the deaerator is to separate and remove the non-condensable gas in the boiler feed water, that is, deaerate and prevent corrosion of the equipment by heating the steam turbine for power generation and the feed water directly in contact with each other. Is installed.
[0003]
In such a power generation steam turbine plant, when a water supply tube arranged in the condenser, feed water heater, or deaerator breaks and water leaks, the water leaks up the extraction pipe to generate power. Water will enter the steam turbine for industrial use. This phenomenon is called “warning”, and this causes damage to the moving blades, stationary blades, rotors, etc. of the steam turbine for power generation.
[0004]
The conventional method will be described below with reference to FIG. 3, taking a feed water heater as an example. In FIG. 3, the steam turbine 31 for power generation, the feed water heater 32, the bleed pipe 33 flowing from the steam turbine 31 for power generation into the feed water heater 32, the shut-off valve 34 provided in the middle of the pipeline, and the feed water heater The water level detector 35 for measuring the water level 32 and a warpage prevention circuit 36 for giving a command to the shutoff valve 34 based on the water level in the feed water heater 32 obtained from the water level detector 35 are installed. .
[0005]
In such a power generation steam turbine plant, the water level in the feed water heater 32 that is an inflow source of water into the power generation steam turbine 31 is constantly monitored by the water level detector 35 in the feed water heater, and the water level is dangerous. When the water level rises above the level, the shut-off valve 34 is fully closed by a command from the warpage prevention circuit 36 and the inflow conduit between the power generation steam turbine 31 and the feed water heater 32 is shut off.
[0006]
In the conventional method, the amount of steam flowing into the condenser, feed water heater, and deaerator from the power generation steam turbine 31 in the normal state and discharged from the condenser, feed water heater, deaerator to the drain tank, etc. The amount of exhaust air discharged is balanced and controlled to maintain a constant water level, but when a water supply tube installed in the condenser, feed water heater, or deaerator is damaged and water leakage occurs. The water level in the condenser, feed water heater and deaerator rises abnormally. Then, the water level detector in the feed water heater detects that the dangerous water level has been reached, and the shut-off valve 34 in the middle of the pipeline is fully closed by a command from the war-taction prevention circuit 36 to prevent the war-taction from being reached. It was a thing.
[0007]
[Problems to be solved by the invention]
However, there are cases where the water level in the condenser, feed water heater, and deaerator rises to a dangerous water level other than during the time of the warning. For example, in the process of shutting down the power generation steam turbine, the amount of steam flowing into the power generation steam turbine may change suddenly and the internal pressure of each other may be reversed. This influence causes the inside of the condenser, feed water heater, deaerator. Water levels may rise to dangerous water levels. Therefore, this method has a problem in that it is fully closed except when a warning action occurs.
[0008]
The mechanical principle leading to the generation of the wartization is that when the pressure in the condenser, feed water heater, and deaerator becomes higher than the pressure in the steam turbine for power generation, the condenser, feed water heater, deaeration The water in the vessel flows back into the steam turbine for power generation. For this reason, the present invention provides a drain pot in the middle of the steam inflow pipeline to detect the water level of the drain pot, and prevents the shut-off valve from being fully closed except during the occurrence of the warning while maintaining the basic function of the warning action. The purpose is to do.
[0009]
[Means for Solving the Problems]
In the power generation steam turbine plant having a shut-off valve installed in the middle of the steam inflow line between the power generation steam turbine and the feed water heater, a water potion prevention device according to the present invention is provided with a drain pot in the middle of the steam inflow line. The gist of the present invention is to provide a water level detector in the drain pot for detecting the water level of the drain pot and to close the shutoff valve based on the detection result of the water level detector in the drain pot.
[0010]
Furthermore, the water-intake prevention device according to the present invention is provided with a water level detector in the feed water heater in the feed water heater, and based on both detection results of the water level detector in the feed water heater and the water level detector in the drain pot. The gist is that the shut-off valve is closed.
[0011]
Furthermore, the gist of the water-induction preventing device according to the present invention is that a check valve is provided on the steam turbine for power generation at the branch point between the steam inflow conduit and the drain pot.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the following, the first embodiment of the present invention will be described with reference to FIG. 1, taking a feed water heater as an example. In FIG. 1, there are a power generation steam turbine 11, a feed water heater 12, a bleed pipe 13 flowing from the power generation steam turbine 11 to the feed water heater 12, and a shutoff valve 14 provided in the middle of the pipeline. Further, a drain pot 15 is provided between the shut-off valve 14 and the feed water heater 12, and the shut-off valve 14 and the drain discharge ON are turned on based on a detection signal obtained from the drain pot water level detector 16 that measures the water level in the drain pot 15. / Warning prevention circuit 18 for giving a command to OFF valve 17 is provided.
[0013]
In the above-described configuration, the value of the water level detector 16 in the drain pot is always monitored by the warming prevention circuit 18, and when the water level in the drain pot 15 rises above the safe water level, the shut-off valve is instructed by a command from the warming prevention circuit 18. 14 is fully closed and a fully open command is output to the drain discharge on / off valve 17 to shut off the inflow line between the power generation steam turbine 11 and the feed water heater 12 and to open the drain discharge line of the drain pot 15. It is a method of fully opening and preventing war-tensioning.
[0014]
Although drain pot 15 are only set in the middle pipe of the bleed pipe 1 3, check valve 20 is provided in the branch point of the extraction pipe 1 3 and drain pot 15. As a result, only the water from the feed water heater 12 toward the power generation steam turbine 11 flows into the drain pot 15.
[0015]
Next, a second embodiment of the present invention will be described with reference to FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals. In the steam turbine plant for power generation described in the first embodiment, a water level detector 19 in the feed water heater, which is a conventional technique, is installed. In such a power generation steam turbine plant, the water level in the drain pot 15 is measured by the water level detector 16 in the drain pot, and the water level in the feed water heater 12 is measured by the water level detector 19 in the feed water heater.
[0016]
Then, these values are constantly monitored by the war- ning prevention circuit 18, and when the water level in the drain pot 15 rises above the safe water level, and when the water level in the feed water heater 12 rises above the dangerous water level, the war-action occurs. Therefore, the shutoff valve 13 is fully closed and the drain discharge on / off valve 17 is fully opened in accordance with a command from the warming prevention circuit 18 to prevent the warming.
[0017]
【The invention's effect】
According to the present invention, it is possible to improve the problem that the shut-off valve is fully closed at the time other than the occurrence of the warping action, which is a problem, while leaving the basic function of the conventional warning action prevention function.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a warpage prevention device according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing a warpage prevention device according to another embodiment of the present invention.
FIG. 3 is a configuration diagram showing a conventional warpage prevention device.
[Explanation of symbols]
11 ... power generation steam turbine 12 ... feed water heater 13 ... extraction piping 14 ... shutoff valve 15 ... drain pot 16 ... drain pot water level detector 17 ... Drain for on / off valves 18 ... water induction prevention circuit 19 ... Water Heater water level detector 20 ... check valve

Claims (3)

In a steam turbine plant for power generation having a shut-off valve installed in the middle of the steam inflow line between the power generation steam turbine and the feed water heater, a drain pot is provided in the middle of the steam inflow line, and the water level of this drain pot is detected. A water potage prevention device characterized in that the water level detector in the drain pot and the shutoff valve are closed based on the detection result of the water level detector in the drain pot. The feed water heater is provided with a water level detector in the feed water heater, and the shutoff valve is closed based on both detection results of the water level detector in the feed water heater and the water level detector in the drain pot. The war-tension prevention device according to claim 1. 3. The warning anti-warming device according to claim 1 , wherein a check valve is provided on a side of the steam turbine for power generation at a branch point between the steam inlet pipe and the drain pot.

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