JPS62255503A - Erosion monitoring method for nozzle blade of steam turbine - Google Patents

Abstract

PURPOSE:To enable the amount of erosion of nozzle blades of a steam turbine to be quantitatively monitored, by measuring pressure and temperature on the upstream and downstream steam of each of 1st stage nozzle, a regulating valve, and a main steam stop valve, and the opening of said regulating valve, so as to evaluate said amount of erosion. CONSTITUTION:A pressure gauge P0 and a thermometer T0 are installed to a main steam pipe 1, a pressure gauge P0' between a main steam stop valve 2 and each of steam regulating valves 3, and pressure gauges P1 to lead pipes 4. Further, a pressure gauge P2 and a thermometer T2 are installed, at the outlet of nozzle blades 6 and valve opening meters L to said regulating valves 3. Using the data obtained by the above measuring instruments, the amount of steam flow through said nozzle blades 6 and the current nozzle area thereof can be evaluated. Comparing these values with those obtained when said nozzle blades were in a sound condition, the amount of nozzle erosion is quantitatively determined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for quantitatively monitoring the state of 20-john generation and growth in the first stage nozzle blade of a steam turbine.

[Conventional technology]

Recently, the mainstream of newly constructed power plants is large-capacity and nuclear power plants. Therefore, existing thermal power plants are started and stopped every day and on weekends for load adjustment operation.

For this reason, the nozzle blades of steam turbines are placed under extremely severe conditions with respect to the occurrence of erosion due to oxidized scale scattered from the boiler.

Application No. 59- as a method for monitoring nozzle blades
249676 and attached thereto, a patent application has been filed for a method of measuring and comparing steam conditions in the vicinity of a nozzle box. The feature of this invention is that a pressure gauge is installed in front of the nozzle,
By detecting this pressure and comparing it with a preset setting value, it is possible to determine whether or not to continue operation and whether to open and inspect the turbine. Therefore, it is necessary to directly and quantitatively monitor the amount of nozzle erosion itself.

An object of the present invention is to provide a method for quantitatively calculating and monitoring nozzle erosion.

〔Example〕

FIG. 1 shows the configuration of the steam turbine inlet section of the present invention. The steam is main steam '171. Main steam stop valve2. Steam control valve 3,
It passes through the lead pipe 4, flows into the nozzle box 5, and flows out from the nozzle 6 into the turbine.

FIG. 2 is a diagram representing FIG. 1 in another form.

The main steam pipe 1 has a pressure gauge P. , thermometer T. is installed. A pressure gauge P is installed between the main steam stop valve 2 and the steam control valve 3.
0', and each lead pipe 4 has a pressure gauge P1,
A pressure gauge P2 and a thermometer T2 are installed at the nozzle outlet. Further, each of the steam control valves 3 is provided with an opening gauge.

Here, the steam #, G1 passing through the nozzle 5 is here:
ψ: Nozzle flow coefficient AN: Nozzle area ■,: Steam specific volume before the nozzle g: Gravitational acceleration k: Ratio of constant pressure specific heat to constant volume specific heat of steam P1: Pressure before the nozzle P2: Pressure after the nozzle Here, On the other hand, the amount of steam Gc passing through the steam control valve 3 is as follows.

ζC: Adjustment valve flow coefficient Ac (L): Adjustment valve area v0 at the adjustment opening degree
'; Specific volume of steam before the control valve Po': Pressure before the control valve where Gc:=G.

Therefore, the nozzle surface fJ　AN　N is OW It is expressed as

Nozzle area A1 in a healthy state. +: Nozzle area when two corrosions occur As described above, according to this embodiment, nozzle erosion can be quantitatively monitored.

FIG. 3 shows a system configuration diagram according to the present invention.

The measured data is processed by the computer G and displayed on the display device 7. Calculator 6 calculates the steam flow rate and nozzle area from the measurement data, basic data, and steam amount, compares it with the healthy state, calculates the erosion ratio, and compares it with the preset allowable nozzle area ANmax. , ma
If x is exceeded, a warning is displayed on the display device 7.

〔Effect of the invention〕

According to the present invention, the amount of nozzle erosion can be quantitatively monitored.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a steam inlet section according to an embodiment of the present invention, FIG. 2 is a block diagram of a steam inlet section, and FIG. 3 is a system block diagram.・′°−1ne. ,)

Claims (1)

[Claims] 1. Measure the pressure and temperature before and after each of the first-stage nozzle, steam control valve, and main steam stop valve of the steam turbine, as well as the opening degree of the steam control valve, and check whether the steam turbine is in a healthy state or has not suffered from erosion. A method for monitoring nozzle blade erosion of a steam turbine, characterized in that changes in steam flow rate and changes in nozzle area are calculated by comparing operating values in a state where the erosion occurs and the state of growth of the erosion is monitored. . 2. In claim 1, the pressure after the nozzle,
A method for monitoring nozzle blade erosion of a steam turbine, characterized in that a value after the first stage rotor blade is used as the temperature.