improving efficiency & reliability of steam turbine through r & m by: amitabh srivastava...

Improving Efficiency & Reliability

of

STEAM TURBINEThrough R & M

BY:AMITABH SRIVASTAVA

SR.DGM, BHEL HARDWAR

IN THE PRESENT POWER SECTOR SCENARIO

FOCUS IS ON

• ENHANCING EFFICIENCY• RELIABILITY• STRICTER POLLUTION NORMS• COST REDUCTION

RESULTING TO ENHANCED EMPHASIS ON

=> REDUCTION IN GENERATION COST

HIGH EFFICIENCY OF TG CYCLE LOWER EQUIPMENT COST SHORTER GESTATION PERIOD REDUCED MAINTENANCE TIME

=> INCREASED RELIABILITY

=> MINIMIZING ENVIRONMENTAL HAZARDS

IMPROVEMENT IN STEAM TURBINE IMPROVEMENT IN STEAM TURBINE PERFORMANCEPERFORMANCE

POSSIBLE BY1. IMPROVED BLADE PROFILE• REDUCTION IN THE AERODYNAMIC

FLOW LOSSES e.g.PROFILE LOSSSECONDARY FLOW LOSSTIP LEAKAGE LOSS

•MORE UNIFORM FLOW DISTRIBUTIONCONTD……..

IMPROVEMENT IN STEAM TURBINE IMPROVEMENT IN STEAM TURBINE PERFORMANCEPERFORMANCE

POSSIBLE BY ….contd...

2. OPTIMISED FLOWPATH

3. IMPROVEMENT IN SHAFT SEALING SYSTEM

4. REDUCTION IN PRESSURE DROPS

5. REDUCED FRICTION LOSSES

6. OPTIMISATION OF INLET & EXHAUST SECTION

7. OPTIMISED EXHAUST LOSS

DEVELOPMENT OF PROFILES FOR DEVELOPMENT OF PROFILES FOR

CYLINDRICAL TURBINE BLADESCYLINDRICAL TURBINE BLADES

T4 PROFILE HAS 1% LOWER PROFILE LOSSES COMPARED TO T2 PROFILE.

NEWLY DEVELOPED TX HAS 0.2% LOWER PROFILE LOSSES COMPARED TO T4 PROFILE.

CONSIDERATIONS IN RETROFITTING & CONSIDERATIONS IN RETROFITTING & UPGRADATION OF OLDER SETSUPGRADATION OF OLDER SETS

• COST EFFECTIVENESS• MODIFICATIONS IN TURBINE INTERNALS ONLY• INCREASE IN POWER OUTPUT WITH MINIMUM CHANGES• OUTER CASING, PIPINGS, VALVES, PEDESTAL FIXING ARRANGEMENT , STEAM PARAMETERS & FOUNDATION DETAILS REMAIN UNALTERED• SHORTEST POSSIBLE OUTAGE TIME

RETROFITTING & UPGRADATION OF OLDER RETROFITTING & UPGRADATION OF OLDER SETSSETS

PRE-REQUISITE

•IDENTIFY THE UNIT

•PRESENT LEVEL OF PERFORMANCE

•RESIDUAL LIFE ASSESSMENT STUDY OF CRITICAL COMPONENTS

•ANALYSIS OF HISTORY & OPERATING DETAILS

RETROFITTING & UPGRADATION OF OLDER RETROFITTING & UPGRADATION OF OLDER SETSSETS

MAJOR MODIFICATIONS INMAJOR MODIFICATIONS IN GUIDE & MOVING BLADEGUIDE & MOVING BLADE

(LATEST STATE OF ART (LATEST STATE OF ART PROFILE)PROFILE)

STEAM FLOWPATHSTEAM FLOWPATH ROTORS & INNER CASINGS ROTORS & INNER CASINGS

OF TURBINEOF TURBINE SHAFT SEALINGSSHAFT SEALINGS [ADVANTAGE IN HEATRATE [ADVANTAGE IN HEATRATE

/ OUTPUT CAN BE WORKED / OUTPUT CAN BE WORKED OUT ON CASE TO CASE OUT ON CASE TO CASE BASIS]BASIS]

3 DS BLADE

(HPT/IPT)

TWISTED PROFILE

BLADE (HP/IPT)

BANANA TYPE

BLADE (LPT)

Retrofitting of HP Turbine

with

STATE OF ART REACTION BLADING

210 MW STEAM TURBINE

(IMPULSE DESIGN SET-LMW) HP TURBINE

EXISTING 210 MW HP TURBINE EXISTING 210 MW HP TURBINE WITH IMPULSE BLADINGWITH IMPULSE BLADING

PROPOSED NEW DESIGN WITH PROPOSED NEW DESIGN WITH LATEST STATE OF ART BLADINGLATEST STATE OF ART BLADING

210 MW STEAM TURBINE (IMPULSE DESIGN SET) HP TURBINE

EXISTINGEXISTING IMPULSE BLADING ( PRESSURE DROP

ONLY IN STATIONARY BLADES)

EFFICIENCY : 83.6 % (FOR NEW MACHINE) EFFICIENCY FOR

EXISTING CONDITION : ~ 80%

NEWNEW REACTION BLADING

( PRESSURE DROP IN STATIONARY AS WELL AS MOVING BLADES

EFFICIENCY : 86.5 %

HP TURBINE

ACTIVITIES INVOLVED

REMOVAL OF EXISTING HP ROTOR, LINERS AND DIAPHRAGMS

INSTALLATION OF NEW LINERS FITTED WITH STATIONARY BLADES AND NEW HP ROTOR

FITTING DIMENSIONS ARE TO BE MEASURED DURING PREVIOUS OVERHAUL AND LINERS ARE MACHINED ACCORDINGLY.

REMOVED HP ROTOR AND DIAPHRAGMS CAN BE USED AS SPARE FOR OTHER SETS

THE RETROFIT CAN BE DONE WITHIN NORMAL OVERHAUL PERIOD.

PAY BACK PERIOD IS LESS THAN 3 YEARS

ACTIVITIES INVOLVEDACTIVITIES INVOLVED

A. Reference data for ORIGINAL brand new turbineReference Heat Balance Diagram TCD - 210 - 33 - 2, Regime No. 1

Rated parameters

Main steam Flow 662 T/h

Main Steam Pressure 130 ata

Main Steam Temperature 535 Deg C

Hot reheat Temperature 535 Deg C

Condenser Vacuum 0.1042 ata

TG Heatrate 2062 kCal/kWh


Rated parameters







B. Expected present performance level (210 MW Original rating)

Considering deterioration due to ageingdeterioration due to ageing as per ASME-PTC-6Report 1985•Expected Power output

with 662 T/h main steam flow

and rated parameters 202.4 MW

•Expected TG Heatrate with 662 T/h main steam flow

and rated parameters 2164 kCal/kWh







EXPECTED PERFORMANCE IMPROVEMENT EXPECTED PERFORMANCE IMPROVEMENT IN THE EXISTING IMPULSE DESIGN SET DUE IN THE EXISTING IMPULSE DESIGN SET DUE TO HP TURBINE REFURBISHMENTTO HP TURBINE REFURBISHMENT

INCREASE IN POWER OUTPUT : 8.6 MW

IMPROVEMENT IN HEATRATE : 4% (FROM EXISTING PERFORMANCE LEVEL OF

THE SET WITH RATED STEAM PARAMETERS & THROTTLE STEAM FLOW)

BRAND NEW SET

EXPECTED PRESENT

DETERIORATED CONDITION

UPGRADED HPT

OUTPUT (MW)

210 202.4 (3.6% DECREASE)

211 (4.2% INCREASE)

HEAT RATE (KCAL/ KWh)

2062 2164 (4.9% INCREASE)

2077 (4.02% IMPROVEMENT)

EXPECTED PERFORMANCE IMPROVEMENT IN THE EXPECTED PERFORMANCE IMPROVEMENT IN THE EXISTING IMPULSE DESIGN SET DUE TO HP TURBINE EXISTING IMPULSE DESIGN SET DUE TO HP TURBINE

REFURBISHMENTREFURBISHMENT

COMPARISONCOMPARISON

GAIN WITH UPRATED HPT:

ADDITIONAL GEN. OF MU = MW X1000 X HRS.X PLF

= 8.6 X 1000 X 8000 X 0.80 = 55.04 MU

ADDITIONAL GEN. OF REVENUE @ RS 2/= PER UNIT

= 55.04 X 2 = RS 11 CR

200/210 MW IMPULSE DESIGN SET

(LMW)

EXISTING AFTER RETROFIT

WORK INVOLVED IN RETROFIT OF LP WORK INVOLVED IN RETROFIT OF LP TURBINETURBINE

WORK TO BE DONE AT SITE:

•CUTTING OF DEFLECTORS / RIBS & BLANKING THE SPACE IN LP CASING TO FACILITATE REMOVAL OF BAUMEN STAGE.•MODIFICATION OF STRUCTURE AT THE EXHAUST END OF LPC TO FACILITATE INSTALLATION OF DIFFUSOR.

CONTD….

• MODIFICATION OF STRUCTURE AT THE STEAM INLET END OF LPC TO FACILITATE INSTALLATION OF 1ST STAGE OF GUIDE BLADES.

WORK INVOLVED IN RETROFIT OF LP WORK INVOLVED IN RETROFIT OF LP TURBINETURBINE

WORK TO BE DONE AT SITE:


Rated parameters








Rated parameters







EXPECTED PERFORMANCE EXPECTED PERFORMANCE IMPROVEMENT IN THE EXISTING SET IMPROVEMENT IN THE EXISTING SET

DUE TO LP TURBINE REFURBISHMENTDUE TO LP TURBINE REFURBISHMENT

INCREASE IN POWER OUTPUT : 10.1 MW

IMPROVEMENT IN HEATRATE : 102 KCAL / KWH

(FROM EXISTING PERFORMANCE LEVEL OF THE

SET WITH RATED STEAM PARAMETERS & THROTTLE STEAM FLOW)

BRAND NEW ST

EXPECTED PRESENT DETERIORATED CONDITION

UPGRADED LPT

OUTPUT (MW)

210 202.4 212.5HEAT RATE (KCAL / KWH)

2062 2164 2066

ADDITIOAL GEN (MU)

NA NA 64.64



GAIN WITH UPRATED LPT:


= 10.1 X 1000 X 8000 X 0.80 = 64.64 MU


= 64.64 X 2 = RS 12.93 CR

BRAND NEW ST

EXPECTED PRESENT DETERIORATED CONDITION

UPGRADED HPT

UPGRADED LPT

UPGRADED HPT & LPT

OUTPUT (MW)

210 202.4 211 212.5 214HEAT RATE (KCAL / KWH)

2062 2164 2077 2066 2047

ADDITIOAL GEN (MU)

NA NA 55.04 64.64 74.24



GAIN WITH UPRATED HPT & LPT:


= 11.6 X 1000 X 8000 X 0.80 = 74.74 MU


= 74.74 X 2 = RS 14.848 CR

TECHNICAL PROPOSAL

FOR R & M OF 210 MW STEAM TURBINES (KWU DESIGN) OF TUTICORIN

TPS

CROSS SECTIONAL VIEW OF 210 MW STEAM TURBINE

EXISTING DESIGN:

HP Turbine:•HP ROTOR : WITH MOVING BLADES OF T2 PROFILE

•INNER CASING: WITH STATIONARY BLADES OF T2 PROFILE

•INLET INSERTS: WITH 580X9 MM BUTTRESS THREADS

•EXHAUST ELBOWS: WITH SERRATED GASKET.

210 MW STEAM TURBINE (REACTION DESIGN SET-KWU)

HP TURBINE

RETROFITTING 210 MW REACTION TURBINE WITH IMPROVED BLADING

HP INLET INSERTS

BREECH NUT

HP OUTER CASING

IMPROVEMENTS IN PROPOSED DESIGN:

HP MODULE:

•INNER CASING & HP ROTOR WITH OPTIMISED HIGHLY EFFICIENT T4 PROFILE BLADING.

ADVANTAGE:INCREASED EFFICIENCY

IMPROVEMENTS IN PROPOSED DESIGN: (CONTD.)

HP MODULE (CONTD.):

• MODIFIED HPT INLET INSERTS WITH BUTTRESS THREADS OF SIZE 580X20 MM IN HP OUTER CASING & BREECH NUTS.

ADVANTAGE:EASE IN ASSEMBLY & DISMANTLING.

IMPROVEMENTS IN PROPOSED DESIGN: (CONTD.)

HP MODULE (CONTD.):

MODIFIED HP EXHAUST ELBOWS WHICH HAVE U-RING IN PLACE OF SERRATED GASKET.

ADVANTAGE:ENHANCED RELIABILITY.

HP EXHAUST ELBOWS

Exhaust ElbowHP OUTER CASING

HP EXHAUST ELBOWS

HP EXHAUST ELBOWS

U-RING

SCOPE OF SUPPLY

FOR HP TURBINE:

•COMPLETELY ASSEMBLED HP MODULE WITH T4 PROFILE BLADING ALONGWITH MODIFIED HP INLET ASSEMBLY & HP EXHAUST ELBOWS.

210 MW STEAM TURBINE

(REACTION DESIGN SET-KWU)

IP TURBINE

RETROFITTING 210 MW REACTION TURBINE WITH IMPROVED T4 PROFILE BLADING

ADVANTAGE:IMPROVED PERFORMANCE.

SCOPE OF SUPPLY (CONTD.)

FOR IP TURBINE:

•IP INNER CASING & IP ROTOR WITH T4 PROFILE BLADING.•A SET OF HPR-IPR & IPR-LPR COUPLING BOLTS.•NECESSARY KEYS ETC.

WORK REQUIRED TO BE DONE AT SITE:

[NOT INCLUDED IN THE SCOPE OF THIS TECHNICAL OFFER]

•PERFORMANCE TESTING PRIOR & AFTER R & M.•OVERHAULING.•RLA STUDY.•COMPONENTS IDENTIFIED DURING OVERHAULING/ RLA STUDY WHICH NEED REPLACEMENT

WORK REQUIRED TO BE DONE AT SITE: (FOR HP Turbine)

•REMOVAL OF OLD HP MODULE FROM ITS

POSITION AFTER DISMANTLING OF HP

INLET INSERTS AND HP EXHAUST ELBOWS.

•OLD HP INLET ASSEMBLY (INLET INSERTS

WITH BREECH NUTS) & HP EXHAUST

ELBOWS ARE TO BE CUT FROM MS PIPES &

CRH PIPES RESPECTIVELY.

WORK REQUIRED TO BE DONE AT SITE:(CONTD.)

•INSTALLATION OF NEW IMPROVISED

HPT MODULE IN POSITION, CENTERING

& ALIGNMENT.

•WELDING OF HP INLET ASSEMBLY OF

NEW MODULE WITH MAIN STEAM PIPES.

WORK REQUIRED TO BE DONE AT SITE:(CONTD.)

•HP EXHAUST ELBOWS ARE TO BE WELDED WITH CRH STEAM PIPES.

•ASSEMBLY OF HP INLET INSERTS & HP EXHAUST ELBOWS TO BE COMPLETED.

WORK REQUIRED TO BE DONE AT SITE:FOR IP Turbine

•REMOVAL OF OLD IP ROTOR & IP INNER CASING.•INSTALLATION OF NEW IP INNER CASING & IP ROTOR WITH T4 PROFILE BLADING, ITS CENTERING & ALIGNMENT.•COMPLETION OF BOX UP OF IP Turbine.

CONDITION AFTER R & M OF HPT & IPT (UNDER RATED CONDITION):

RATED PARAMETERS:At 100% MCR condition

•MAIN STEAM FLOW : 641.3 T/HR•MS/ HRH STEAM TEMP:535/535 DEG C•MAIN STEAM PR: 150 ATA•BACK PR: 0.121 ATA

EXPECTED PRESENT PERFORMANCE:

CONSIDERING DETERIORATION DUE TO AGING AS PER ASME-PTC-6 REPORT 1985 FOR AVERAGE LIFE OF 20 YEARS, FOLLOWING WILL BE EXPECTED PERFORMANCE AT 641.3 T/HR MAIN STEAM FLOW AND RATED PARAMETERS OUTPUT: 202.3 MW HEAT RATE: 2067 KCAL/KWH

COMPARISON OF PERFORMANCE:

PAY BACK PERIOD

1) REDUCTION IN OH PERIOD: 25 DAYSRESULTING TO

ADDITIONAL POWER GENERATION FOR 25 DAYS

YIELDING TO

GUAREENTED MINIMUM ADDITIONAL REVENUE:= 209MW x 1000 x 25DAYS x 24HRS x 0.80PLF x 2.00RS

=RS 20.06 CRORES

PAY BACK PERIOD

2) ADDITIONAL ANNUAL REVENUE GENERATION DUE TO INCREASE IN OUTPUT & IMPROVED HEAT RATE:

= 6.7 MW x 1000 x 8000 HRS x 0.80 PLF x RS 2.00

= RS 8.576 CRORES PER YEAR

HENCE, PAY BACK PERIOD < 3 YEARS

improving efficiency & reliability of steam turbine through r & m by: amitabh srivastava...

Documents

sets slide

retrofitting of hp turbine

turbine internals

bhel hardwar slide

optimised exhaust loss

lower profile losses

new hp rotor

t2 profile