multi hole bypass valve for epri australia 2008 final

8/4/2019 Multi Hole Bypass Valve for EPRI Australia 2008 Final

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Proprietary Information Toshiba Corporation 2008, All Rights Reserved

EPRI MCR meeting in Australia

Multi-hole Bypass ValveOctober 2008Toshiba CorporationToshiba International Corp Pty Ltd.


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2Proprietary Information Toshiba Corporation 2008, All Rights Reserved

High erosion rates for units with

solid particle erosion (SPEexfoliation of the boiler tubesfrom thermal transients).

SPE in the steam flow impinges

onto the bypass valve skirt and

erodes the Stellite away. Oncethrough the Stellite, the parentmaterial is softer and wearsfaster.

If left unattended, the skirt will

break apart and go downstreamthrough the turbine. This typically resulted in

replacement of the bypass valveson an annual basis.

Original Main Stop Bypass Valve


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If the erosion was allowed to proceed, parts couldhave broken off and carried through to the 1st stagenozzles and through the turbine.

Skirt is partially or fully

erodedValve stem under Skirt is eroded

Example of Damaged Bypass Valve & Stem


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Very limited erosion isobserved around Multi-hole

Photo shows

this parts

The photo shows an example of a valve used from 1991 to 2005in a 500MW supercritical turbine.

Multi Hole Bypass Valve needs no repair/replacement

over 10 years even under severe conditions.

SPE Resistance is Proven


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Operation Experience of Multi-Hole Valve (MSV) 1/2


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Plant code

Operation Experience of Multi-Hole Valve (MSV) 2/2


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Option 1 Option 2 Option 3

Main Valve X X X

Bypass Valve X X X

Valve Stem X12Cr with Nitride

X12Cr with Nitride

XIncoloy

Pressure SealHead

Modify and reuseexisting seal head

X12Cr with Nitride Bush

XStellite Bush

Assembly

Component Life

Expectancy

10+ years 10+ years 10+ years

RecommendedOverhaul Interval

2-4 years(Depends on Oxidation scale of Stem and Bush)

4-8 years(First overhaulafter 2 years)

Variation of Replacement Scope


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Worldwide application of multi-hole bypass valve

First installations in the mid-late 1980s in Japan. Installed in over 70units in Japan. Long term operation of these units have confirmed the

success of this valve.

First installation outside of Japan in 1999 at Az-Zour #1 in Kuwait(Ministry of Electric Power (MEP), 4 x 300MW units)Now installed at all 4 Az-Zour units.

Installed in Incheon #1 (2004) and Incheon #2 (2005) in Korea (KoreaMidland Power Co (KOMIPO), 2 x 250MW units)

First USA unit installed at Duck Creek (Ameren) in 2006. Now suppliedfor 4 Ameren units.

The first Australian application will be at Mount Piper Powerstation (Delta Electricity, 2 x 660MW). Toshiba will supply andinstall multi-hole bypass valves for both Mt Piper units next year.


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Case Study for Ameren (US Utility)

Ameren Reference of Toshiba BypassValve

Duck Creek #1Installed January 2006First inspection February 2007

Second inspection February 2008after approx 200hr bypass operation

Coffeen #1Installed in Autumn (U.S. Spring) 2008

Coffeen #2

Delivered, to be installed Spring (U.S. Fall) 2009 Sioux #1

Installed Spring (U.S. Fall) 2008

Duck Creek #1


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Duck Creek #1 The First Application to non-Toshiba unit

The first valves were successfully installed to Ameren Duck Creek #1 in January 2006 in 4days (hardware replacement & adjustment), and the unit restarted without problem.

Replace valve

Adjust valve stroke

Adjust limit switch

Adjust EHC function


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Inspection after first year of Operation ~ 35 hours on bypass

Unit removed from service in February 2007for installation of a Toshiba HP-IP turbine,

boiler rebuild and other plant projects. The valves were disassembled and

inspected for condition assessment.

Inspections provided favorable results verylittle erosion, no scale buildup on the stem orbushings

Presentation material courtesy of Ameren


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Close-up of bypass holes with minimal erosion



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Pressure seal head bushings (stellite liner) with no scale



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Incoloy Stem no scale and no bowing



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16Proprietary Information Toshiba Corporation 2008 All Rights Reserved

Inspection after 2 year of Operation

Duck Creek Inspection Resultafter approx 200hr Bypass Operation

Average Erosion Most Eroded Portion

Very limited erosion was observed

multi hole bypass valve for epri australia 2008 final

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