Dehydrogenation processing method for turbine blades

Patent metadata

Field	Value
Publication number	US-11066715-B2
Application number	US-201716086705-A
Country	US
Kind code	B2
Filing date	Mar 6, 2017
Priority date	Mar 31, 2016
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A dehydrogenation processing method for a turbine blade of a steam turbine. The method includes a step of heating the turbine blade by suppling heating steam into a casing of the steam turbine after a steam turbine plant is stopped. The heating steam supplied to the casing has a temperature that is higher than steam passing through the turbine blade during operation of the steam turbine plant. The method further includes repeating the process of supplying the heating steam into the casing a multiple of times.

First claim

The invention claimed is:

1. A dehydrogenation processing method for a turbine blade of a steam turbine, the method comprising:
a step of heating the turbine blade by supplying heating steam into a casing of the steam turbine after a steam turbine plant is stopped,
wherein the heating steam has a higher temperature than steam passing through the turbine blade during operation of the steam turbine plant, and
repeating the process of supplying the heating steam into the casing of the steam turbine, wherein the process of supplying the heating steam into the casing is repeated multiple times.

2. The dehydrogenation processing method for a turbine blade according to claim 1 ,
wherein the step of heating the turbine blade includes supplying gland steam as the heating steam into the casing via a gland seal portion of the steam turbine.

3. The dehydrogenation processing method for a turbine blade according to claim 2 ,
wherein the step of heating the turbine blade includes setting the temperature of the gland steam as the heating steam to be higher than gland steam during operation of the steam turbine plant.

4. The dehydrogenation processing method for a turbine blade according to claim 3 ,
wherein the temperature of the gland steam is adjusted by a temperature adjuster disposed in a gland steam line for supplying the gland steam to the gland seal portion.

5. The dehydrogenation processing method for a turbine blade according to claim 4 ,
wherein the temperature adjuster is a desuperheater disposed in the gland steam line between a gland steam header and the gland seal portion, and
wherein the desuperheater is configured to adjust a temperature decrease amount of the gland steam.

6. The dehydrogenation processing method for a turbine blade according to claim 5 ,
wherein the step of heating the turbine blade includes increasing a temperature setting value of the gland steam at the desuperheater compared to during operation of the steam turbine plant.

7. The dehydrogenation processing method for a turbine blade according to claim 2 , further comprising:
introducing the gland steam into the casing by supplying the gland steam into the gland seal portion while maintaining a pressure inside the casing to be less than an atmospheric pressure; and
after heating the turbine blade, increasing the pressure inside the casing to the atmospheric pressure, or stopping supply of the gland steam to the gland seal portion.

8. The dehydrogenation processing method for a turbine blade according to claim 1 ,
wherein the step of heating the turbine blade includes heating the turbine blade to a temperature of 120° C. or higher.

9. The dehydrogenation processing method for a turbine blade according to claim 1 , further comprising:
repeating the process of supplying the heating steam into the casing for multiple times when the steam turbine plant is stopped, until an accumulated execution number of the process reaches a predetermined number.

10. The dehydrogenation processing method for a turbine blade according to claim 1 ,
wherein the turbine blade to be heated includes a final stage blade of a low-pressure steam turbine.

11. The dehydrogenation processing method for a turbine blade according to claim 1 , wherein the turbine blade is made of martensitic stainless steel.

Assignees

• Mitsubishi Hitachi Power Sys
• Mitsubishi Power Ltd

Inventors

• Shimizu Yuichi
• Furukawa Tatsuya
• Matsubara Ryuichi
• Sato Kenji

Classifications

• F01K21/06

  Treating live steam, other than thermodynamically, e.g. for fighting deposits in engine · CPC title

• F01K13/02

  Controlling, e.g. stopping or starting · CPC title

• F01D9/02

  Nozzles; Nozzle boxes; Stator blades; Guide conduits {, e.g. individual nozzles (nozzle boxes F01D9/047)} · CPC title

• F01D25/00

  Component parts, details, or accessories, not provided for in, or of interest apart from, other groups · CPC title

• C21D9/00

  Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor · CPC title