bhel turbine manual

Improving Efficiency & Reliability

ofSTEAM TURBINEThrough R & M

BY:AMITABH SRIVASTAVASR.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 PERFORMANCEPOSSIBLE BY1. IMPROVED BLADE PROFILEREDUCTION IN THE AERODYNAMIC FLOW LOSSES e.g.PROFILE LOSSSECONDARY FLOW LOSSTIP LEAKAGE LOSSMORE UNIFORM FLOW DISTRIBUTIONCONTD..

IMPROVEMENT IN STEAM TURBINE PERFORMANCEPOSSIBLE BY .contd...2. OPTIMISED FLOWPATH3. IMPROVEMENT IN SHAFT SEALING SYSTEM4. REDUCTION IN PRESSURE DROPS5. REDUCED FRICTION LOSSES 6. OPTIMISATION OF INLET & EXHAUST SECTION7. OPTIMISED EXHAUST LOSS

DEVELOPMENT OF PROFILES FOR CYLINDRICAL TURBINE BLADEST4 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 & UPGRADATION 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 SETSPRE-REQUISITEIDENTIFY THE UNITPRESENT LEVEL OF PERFORMANCERESIDUAL LIFE ASSESSMENT STUDY OF CRITICAL COMPONENTSANALYSIS OF HISTORY & OPERATING DETAILS

RETROFITTING & UPGRADATION OF OLDER SETSMAJOR MODIFICATIONS IN GUIDE & MOVING BLADE (LATEST STATE OF ART PROFILE)STEAM FLOWPATHROTORS & INNER CASINGS OF TURBINESHAFT SEALINGS [ADVANTAGE IN HEATRATE / OUTPUT CAN BE WORKED OUT ON CASE TO CASE 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 WITH IMPULSE BLADINGPROPOSED NEW DESIGN WITH LATEST STATE OF ART BLADING210 MW STEAM TURBINE (IMPULSE DESIGN SET) HP TURBINE

PROPOSED NEW DESIGN WITH LATEST STATE OF ART BLADING

HP TURBINEEXISTINGIMPULSE BLADING ( PRESSURE DROP ONLY IN STATIONARY BLADES)EFFICIENCY : 83.6 % (FOR NEW MACHINE)EFFICIENCY FOR EXISTING CONDITION : ~ 80%NEWREACTION BLADING ( PRESSURE DROP IN STATIONARY AS WELL AS MOVING BLADES

EFFICIENCY : 86.5 %

ACTIVITIES INVOLVED

REMOVAL OF EXISTING HP ROTOR, LINERS AND DIAPHRAGMSINSTALLATION OF NEW LINERS FITTED WITH STATIONARY BLADES AND NEW HP ROTORFITTING 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 INVOLVED

A. Reference data for ORIGINAL brand new turbineReference Heat Balance Diagram TCD - 210 - 33 - 2, Regime No. 1 Rated parametersMain steam Flow 662 T/hMain Steam Pressure 130 ataMain Steam Temperature 535 Deg CHot reheat Temperature 535 Deg CCondenser Vacuum 0.1042 ataTG Heatrate 2062 kCal/kWh

B. Expected present performance level (210 MW Original rating)Considering deterioration due to ageing as per ASME-PTC-6Report 1985Expected Power outputwith 662 T/h main steam flow and rated parameters 202.4 MW

Expected TG Heatrate with 662 T/h main steam flowand rated parameters 2164 kCal/kWh

EXPECTED PERFORMANCE IMPROVEMENT IN THE EXISTING IMPULSE DESIGN SET DUE TO HP TURBINE REFURBISHMENTINCREASE IN POWER OUTPUT : 8.6 MWIMPROVEMENT IN HEATRATE : 4% (FROM EXISTING PERFORMANCE LEVEL OF THE SET WITH RATED STEAM PARAMETERS & THROTTLE STEAM FLOW)

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

Sheet1

BRAND NEW SETEXPECTED PRESENT DETERIORATED CONDITIONUPGRADED HPT

OUTPUT (MW)210202.4 (3.6% DECREASE)211 (4.2% INCREASE)

HEAT RATE (KCAL/ KWh)20622164 (4.9% INCREASE)2077 (4.02% IMPROVEMENT)

Sheet2

Sheet3

COMPARISONGAIN 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)

EXISTINGAFTER RETROFIT

WORK INVOLVED IN RETROFIT OF LP TURBINE

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 TURBINEWORK TO BE DONE AT SITE:

A. Reference data for ORIGINAL brand new turbineReference Heat Balance Diagram TCD - 210 - 33 - 2, Regime No. 1 Rated parametersMain steam Flow 662 T/hMain Steam Pressure 130 ataMain Steam Temperature 535 Deg CHot reheat Temperature 535 Deg CCondenser Vacuum 0.1042 ataTG Heatrate 2062 kCal/kWh

B. Expected present performance level (210 MW Original rating)Considering deterioration due to ageing as per ASME-PTC-6Report 1985Expected Power outputwith 662 T/h main steam flow and rated parameters 202.4 MW

Expected TG Heatrate with 662 T/h main steam flowand rated parameters 2164 kCal/kWh

EXPECTED PERFORMANCE IMPROVEMENT IN THE EXISTING SET DUE TO LP TURBINE REFURBISHMENT

INCREASE IN POWER OUTPUT : 10.1 MWIMPROVEMENT IN HEATRATE : 102 KCAL / KWH (FROM EXISTING PERFORMANCE LEVEL OF THE SET WITH RATED STEAM PARAMETERS & THROTTLE STEAM FLOW)

COMPARISON

Sheet1

DESCRIPTIONUNITSTEAM TURBINEWITH UPGRADEDGAIN

BRAND NEWLIKELY PRESENT DETERIORATED PERFORMANCE LEVELHPTLPTWITH UPGRADED HPT% INCREASE (WRT PRESENT LEVEL)WITH UPGRADED LPT% INCREASEWITH UPGRADED HPT & LPT% INCREASE

PLANT DATA

RATED CAPACITY OF TG-SETMW210204212.5212.52.51.22.51.2

LOADING WITH 662 T/HR STEAM FLOWMW210204211.5212.573.438.5415.57.5980392157

HEAT RATE OF STKCAL/KWH2062214020762057.764382.341993.75.6

GENERATION

NO OF UNITS GENERATEDMU1471 (ASSUMING PLF OF 80%)1429 (ASSUMING PLF OF 80%)1482 (ASSUMING PLF OF 80%)1489 (ASSUMING PLF OF 80%)533.70%604.20%1137.9

BENEFIT

SELLING PRICE PER UNITRS / KWH2.32.32.32.32.3NA2.3NA2.3NA

REVENUE GENERATEDRS CRORE338.33328.67340.9342.4712.233.72%13.84.20%267.9

Sheet2

BRAND NEW STEXPECTED PRESENT DETERIORATED CONDITIONUPGRADED LPT

OUTPUT (MW)210202.4212.5

HEAT RATE (KCAL / KWH)206221642066

ADDITIOAL GEN (MU)NANA64.64

Sheet3

COMPARISONGAIN WITH UPRATED LPT:


= 10.1 X 1000 X 8000 X 0.80 = 64.64 MU


= 64.64 X 2 = RS 12.93 CR

COMPARISON

Sheet1

DESCRIPTIONUNITSTEAM TURBINEWITH UPGRADEDGAIN

BRAND NEWLIKELY PRESENT DETERIORATED PERFORMANCE LEVELHPTLPTWITH UPGRADED HPT% INCREASE (WRT PRESENT LEVEL)WITH UPGRADED LPT% INCREASEWITH UPGRADED HPT & LPT% INCREASE

PLANT DATA

RATED CAPACITY OF TG-SETMW210204212.5212.52.51.22.51.2

LOADING WITH 662 T/HR STEAM FLOWMW210204211.5212.573.438.5415.57.5980392157

HEAT RATE OF STKCAL/KWH2062214020762057.764382.341993.75.6

GENERATION

NO OF UNITS GENERATEDMU1471 (ASSUMING PLF OF 80%)1429 (ASSUMING PLF OF 80%)1482 (ASSUMING PLF OF 80%)1489 (ASSUMING PLF OF 80%)533.70%604.20%1137.9

BENEFIT

SELLING PRICE PER UNITRS / KWH2.32.32.32.32.3NA2.3NA2.3NA

REVENUE GENERATEDRS CRORE338.33328.67340.9342.4712.233.72%13.84.20%267.9

Sheet2

BRAND NEW STEXPECTED PRESENT DETERIORATED CONDITIONUPGRADED HPTUPGRADED LPTUPGRADED HPT & LPT

OUTPUT (MW)210202.4211212.5214

HEAT RATE (KCAL / KWH)20622164207720662047

ADDITIOAL GEN (MU)NANA55.0464.6474.24

Sheet3

COMPARISONGAIN 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 PROPOSALFOR 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 TURBINERETROFITTING 210 MW REACTION TURBINE WITH IMPROVED BLADING

HP INLET INSERTSBREECH NUTHP OUTER CASING

HP INLET INSERTSHP INLET INSERTS (OLD DESIGN):HP OUTER CASING & BREECH NUTS THREAD SIZE : 580X9 MM

HP INLET INSERTS (NEW DESIGN):HP OUTER CASING & BREECH NUTSTHREAD SIZE : 580X20 MM

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 ELBOWSExhaust ElbowHP OUTER CASING

HP EXHAUST ELBOWS

HP EXHAUST ELBOWSU-RING

SCOPE OF SUPPLYFOR 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 TURBINERETROFITTING 210 MW REACTION TURBINE WITH IMPROVED T4 PROFILE BLADINGADVANTAGE: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 TurbineREMOVAL 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 conditionMAIN STEAM FLOW : 641.3 T/HRMS/ HRH STEAM TEMP:535/535 DEG CMAIN STEAM PR: 150 ATABACK 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:

BRAND NEW ST

EXPECTED PRESENT CONDITION

AFTER R & M of HPT & IPT

OUTPUT (MW)

210

202.3

209

(GAIN OF 3.3%)

HEAT RATE (KCAL/KWH)

1991

2067

1999.6

(GAIN OF 3.2%)

PAY BACK PERIOD1) 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 PERIODADDITIONAL 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

PRESENT EXPECTED CONDITION:

OUT PUT = 202.3 MW (641.3T/HR)THEREFORE,OUT PUT = 210 MW (665.7 T/HR)FOR THIS FLOW : IT IS OPERATING NEAR TO VWO CONDITION WHICH IS NOT DESIRABLE.

EXPECTED CONDITION AFTER R&M:

OUT PUT = 209 MW (641.3T/HR)THEREFORE,OUT PUT = 216.95 MW (665.7 T/HR)FOR THIS FLOW : IT WILL BE OPERATING NEAR VWO CONDITION WHICH IS NOT DESIRABLE.

bhel turbine manual

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