JP2777061B2 - Device for preventing erosion damage of steam turbine blades by solid particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for preventing erosion damage of steam turbine blades of a thermal power plant, and physically traps solid particles such as peeling scales carried in from a boiler. A method and an apparatus therefor.

[0002]

2. Description of the Related Art In a thermal power plant or the like, there is a demand for measures to prevent erosion damage of steam turbine blades caused by steam oxidation scale peeling off the boiler tube material caused by rapid startup or rapid load change.

The following method has been used as a conventional measure. (1) Countermeasures from the steam turbine side Corrosion resistance is enhanced by the surface hardening treatment of the blades. However, the service life is short, it is expensive, and it needs to be replaced every time it is repaired. The time required for the surface hardening treatment of the wings is several months, and the time required for periodic repairs is significantly longer. If the scale is carried in a large amount, damage may occur in a short period of time, making maintenance management difficult. Since it is not possible to measure the surface hardened layer on site, it is difficult to evaluate the remaining life.

(2) Countermeasures from the boiler side There is use of high-grade tubing that does not easily generate boiler steam oxidation scale, and removal of accumulated scale by cutting the boiler tube.
It is difficult to adopt it because it is not a cost, construction period and fundamental measure. Chemical cleaning is performed to remove the scale on the inner surface of the main steam pipe with chemicals. However, the cleaning work is expensive and workability is poor, and the effect of the main cleaning alone is unknown.
In addition, since the washing is also a coping treatment, it needs to be regularly performed.

[0005]

SUMMARY OF THE INVENTION The present invention provides an inertia force and a centrifugal force to a scale by changing the direction of a scale and a steam flow carried into a main steam pipe from a boiler side, thereby changing the direction of the scale from the steam flow. The purpose is to separate and collect and prevent erosion of turbine blades due to abutment of scale.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a boiler connected to an inlet of a steam turbine.
Direction of the main steam pipe near the inlet,
With a cyclone interposed and cut along the side of the cyclone
Connect the main steam pipe from the boiler side to the upper end of the cyclone
Insert the lower opening of the direction change main steam pipe from the center of the plate,
A scale collection unit is provided at the lower end of the cyclone, and
Solid particles with a scale discharge valve at the lower end of the
Steam turbine blade erosion damage prevention device .

[0007]

According to the present invention, the scale generated in the boiler or the main steam pipe by the kinetic energy of the steam flow in the main steam pipe from the boiler side to the inlet of the steam turbine is directed to the inlet of the steam turbine. The flow direction is changed by striking the wall of the tube in the direction change portion of the main steam pipe provided immediately therearound, and an inertial force is applied in the change direction, and collected by the scale collection portion in the change direction.

The steam flow enters the main steam pipe after the direction change from an intermediate portion between the direction change section and the scale collection section, and is injected from the inlet of the turbine to turbine blades. The scale accumulated in the scale collecting unit is discharged from the discharge valve when the turbine stops.

The main steam pipe communicates tangentially with a cyclone provided in the vicinity of or near the turbine, and the scale is turned down by centrifugal force applied along the inner wall of the cyclone to lower the scale accommodating portion at the lower end. Accumulate in The steam rises from the lower end opening of the direction change main steam pipe inserted into the cyclone at the center of the upper end plate of the cyclone, and is injected from the inlet of the turbine to the turbine blades. The scale accumulated in the scale accommodating section is discharged from the discharge valve when the turbine stops.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a main steam pipe 2 for connecting a boiler and a steam turbine 1, the main steam pipe 2 is bent from the horizontal to the vertical as shown in FIG. A scale discharge valve 5 is provided by an on-off valve 5 '. And branch the horizontal main steam pipe 2 'in the middle of the vertical pipe,
It is connected to the inlet 1 ′ of the steam turbine 1 via the on-off valve 7.

The scale s generated on the inner wall of the main steam pipe 2 separates and moves along with the high-temperature and high-pressure steam flow having a flow velocity of about 60 m / sec. Upon contact, inertial force is applied from the horizontal direction to the vertical direction, and the moving direction changes from horizontal to downward, and is accommodated in the scale collection unit 4 below the vertical tube.

The steam flow is a main steam pipe 2 'branched from a vertical pipe.
And is injected into turbine blades from an inlet 1 ′ of the turbine 1. When the turbine is stopped at the time of periodic inspection of the turbine 1, the scale s accumulated in the scale collecting section 4 below the vertical pipe is discharged by opening the electromagnetic on-off valve 5 '.

As shown in FIG. 2 and FIG.
Of the vertical main steam pipe 2 ′ is inserted through the upper side of the cyclone 6 provided in the vicinity of or near the turbine 1 from the tangential direction, and the lower end opening of the vertical main steam pipe 2 ′ is inserted into the upper end plate central part 6 ′. The other end of the pipe 2 ′ is connected to the steam turbine 1 via the on-off valve 7.
To the inlet 1 'of the vehicle.

The middle part of the cyclone 6 and below has an inverted conical cylindrical shape, and the scale s entering with the high-temperature and high-pressure steam entering from the tangential direction is subjected to centrifugal force along the inner peripheral surface of the cyclone 6. It turns downward and accumulates in the collecting section 4 at the lower end. Then, the steam rises into the vertical main steam pipe 2 ′ and is injected from the inlet 1 ′ of the steam turbine 1 to turbine blades. The size of the collecting unit 4 has such a capacity that it does not re-scatter until the next regular repair.

The scale s is discharged from the solenoid on-off valve 5 'during the stoppage of the turbine 1 due to the periodic inspection, and the scale s is removed from the steam flow in the immediate vicinity of the steam turbine 1 as described above.
Are separated and removed.

[0016]

According to the present invention, as described above, the scale s which flows with the kinetic energy of the high-temperature and high-pressure steam flow from the boiler is provided with an inertial force or a centrifugal force near or near the inlet 1 'of the steam turbine 1. Therefore, it is possible to separate and remove the steam from the steam flow before entering the turbine 1, reduce the scale s that abuts with the steam flow injected to the turbine blade, and reduce the erosion damage of the turbine blade due to the scale s. In addition, the damage to the turbine blades can be reduced , and the period of the regular case hardening replacement process for the turbine blades can be greatly extended.
In addition, there is no need to perform a scale-down operation by chemical cleaning of the inner wall of the main steam pipe 2, and the cost can be greatly reduced.

[Brief description of the drawings]

1 is a side view showing the erosion damage-proof TomeSo location of the steam turbine blade according to the solid particles of the present invention.

FIG. 2 is a plan view of a scale collecting unit using a cyclone.

FIG. 3 is a longitudinal sectional view taken along the line AA of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steam turbine 1 'Inlet 2 Main steam pipe 2' Direction conversion main steam pipe 3 Direction conversion part 4 Scale collection part 5 Scale discharge valve 6 Cyclone 6 'Central part of upper end plate

Claims (1)

(57) [Claims] 1. A boiler side connected to an inlet of a steam turbine
The main steam line from
A cyclone is interposed in the replacement part, and a cut line is made on the side
Connect the main steam pipe from the boiler side in the direction
Insert the bottom opening of the direction change main steam pipe from the center of the top plate
And a scale collection unit is provided at a lower end of the cyclone, and
Solid particles comprising a scale discharge valve provided at the lower end of the collecting section
Erosion damage prevention device for steam turbine blades.