Post on 28-Oct-2014
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
SOME FACTSTOTAL INSTALLED CAPACITY OF INDIA IS 106254.22 MW
71 % OF THE TOTAL ELECTRIC ENERGY GENERATED BY COAL SETS IN THE COUNTRY WAS CONTRIBUTED BY 210 / 250 / 500 MW RATING BHEL SETS THOUGH THEY FORM 63 % OF TOTAL GENERATING CAPACITY OF THE COUNTRY
MORE THAN 60 % OF THE THERMAL MACHINES OPERATING IN INDIA ARE OF KWU DESIGN.
HIGH RELIABILITY,AVAILABILITY,BETTER HEAT RATE, FASTER START UP AND SHUT DOWN,MAINTENANCE FRIENDLY ENABLES HIGHER ACCEPTABILITY AMONGST MOST CUSTOMERS IN INDIA.
KWU TECHNOLOGY HAS WEATHERED IN INDIAN CONDITIONS AND CUSTOMER HAS SHOWN CONFIDENCE BY PLACING REPEAT ORDERS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
PLANT LOAD FACTOR
AND
OPERATIONAL AVAILABILITY
OF SOME NTPC MACHINES
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
87.1
87.4
89.0
92.9
94.0
94.1
95.9
84.9
89.2
96.0
93.5
96.9
95.3
PLF
2002-2003
92.7
92.0
93.3
93.8
93.9
94.2
97.8
90.0
91.3
97.3
95.0
98.2
95.6
OA
82.7
89.1
89.1
89.0
94.7
94.2
76.7
82.6
98.2
98.1
97.1
99.3
100.1
PLF
2003-2004
89.8
87.5
91.2
93.5
90.4
93.2
89.5
92.6
91.2
68.4
78.2
93.0
97.3
PLF
2001-2002
86.6
89.6
79.0
95.6
97.5
96.6
91.0
91.9
97.6
87.8
98.7
98.6
96.6
PLFOA
2000-20011999-2000
85.6
83.7
82.4
91.4
93.5
84.4
95.6
92.7
96.5
93.8
83.7
93.1
98.9
86.792.890.288.8UNIT-6
94.289.393.387.1UNIT-5
93.993.784.586.7UNIT-4
89.694.695.993.5UNIT-3
94.291.497.894.0UNIT-2
93.794.197.185.3UNIT-1KORBA
78.890.692.895.8UNIT-7
87.295.792.192.7UNIT-6
SINGRAULI
PLANT/YEAR
98.192.996.797.8UNIT-5
97.468.588.493.4UNIT-4
97.378.298.183.7UNIT-3
98.793.997.793.0UNIT-2
98.297.094.496.5UNIT-1
OAOAOAPLF
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
87.4
85.8
92.3
93.2
88.5
78.4
82.6
80.8
86.6
92.4
85.3
87.4
88.8
PLF
2002-2003
92.8
92.4
93.4
94.3
89.8
87.7
93.6
90.0
95.1
96.5
88.3
90.3
92.0
OA
96.4
99.4
92.7
85.6
91.8
90.1
93.1
95.4
94.4
94.7
87.1
77.7
93.5
OA
99.2
86.6
84.9
89.2
90.8
94.8
95.6
98.4
92.1
-
-
82.3
68.0
OA
69.1
91.5
89.9
91.5
84.6
91.2
90.2
95.7
97.2
-
-
80.8
75.8
PLF
82.5
71.7
90.2
91.4
87.1
94.3
96.7
97.0
96.6
-
-
-
-
PLF
2003-20042001-20022000-20011999-2000
92.881.695.782.3UNIT-4BADARPUR
90.389.376.092.8UNIT-5
91.583.090.489.3UNIT-6
83.786.892.292.2UNIT-5
88.687.985.790.3UNIT-4RAMAGUNDAM
81.389.591.894.6UNIT-4
84.290.791.997.2UNIT-3
86.194.297.196.6UNIT-2
84.388.497.196.3UNIT-1DADRI
91.6---UNIT-2
84.2---UNIT-1SIMHADRI
88.160.084.5-UNIT-7VINDHYACHAL
74.279.088.4-UNIT-8
PLANT/YEAR
PLFPLFOAOA
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
AGE WISE ANALYSIS OF KWU DESIGN TURBINES SUPPLIED BY BHEL
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
AGE-WISE ANALYSIS
0
21 (2 + 2 + 12 + 5)
29 (6 + 3 + 16 + 4)
31 (11 + 5 + 5 + 10)
21 (3 + 8 + 2+ 8)
15 (4 + 3 + 5 + 3)
210 MW(NR + ER + WR + SR)
00> 25 YRS
0020 – 25 YRS
05 (2 + 0 + 3 + 0)
15 – 20 YRS
08 (0 + 1 + 4 + 3)
10 – 15 YRS
4 (0 + 0 + 2 + 2)
2 (0 + 1 + 1 + 0)
5 – 10 YRS
4 (4 + 0 + 0 + 0)
5 (0 + 1+ 2 + 2)
< 5 YRS
250 MW(NR + ER + WR + SR)
500 MW(NR + ER + WR + SR)
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
A. LP BLADE FAILURE
B. BARRING GEAR STOPPAGE
C. HIGH HP FRONT SHAFT VIBRATION
D. LOW VACUUM DUE TO HIGH AIR INGRESS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
LP BLADE FAILURE :- PROBABLE REASONS
POOR WATER CHEMISTRY
OVERLOADING OF TURBINE
OFF FREQUENCY OPERATION
ALTERATION OF NATURAL FREQUENCY DUE TO EROSION
OF BLADE (OPERATION WITH LOW STEAM PARAMETER &
VWO OPERATION)
LOW VACUUM / HIGH EXHAUST HOOD TEMPERATURE
MECHANICAL RUBBING DUE TO BAD CENTERING
STAGNATION OF WATER IN LP EXTRACTION –1
POOR MACHINING OF BLADE ROOTS / GROOVES
LP WATER INJECTION SYSTEM
POOR MATERIAL OF BLADES
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
LP BLADE FAILURE :- RECOMMENDATIONS / ACTION TAKEN
CONDUCTANCE OF MPI / NFT FOR HEALTHINESS OF LP FREE STANDING BLADES OF 500 / 250 / 210 MW AFTER FIRST 50,000 OPERATING HOURS TO BE CONTINUEDCARE TO BE TAKEN DURING O&M OF THE PLANTAvoid following operation
Off – Frequency operationFull load operation with low vacuumProlonged no load operation Overloading Continuous Valve Wide Open operation
Ensure the proper functioning of following systemsTurbine Drainage SystemLP heaters Drip Cascading auto controls and LP heaters level alarm systemLP exhaust hood spray systemProtection System to avoid incidence of overspeeding, motoring etc.Water chemistry regime
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
ADDITIONAL CHECKS TO BE CARRIED DURING OVERHAULING OF LP MODULE
Centering Check (Record for any rubbing / touching marks at LP casing and LP blade tips)
Replacement of badly eroded LP blades.
Chemical Analysis of salt deposits on LP blades, if any, by customer.
Servicing / inspection of LP exhaust hood spray nozzle to be included in LP module overhaul.
LP BLADE FAILURE :- RECOMMENDATIONS / ACTION TAKEN
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
BARRING GEAR STOPPAGE : PROBABLE REASONS
FAILURE OF LUBRITE PACKERS / KEYS
MAL OPERATION OF GLAND STEAM SYSTEM
CHANGE IN CENTERING OF LP GLAND BOXES
DAMAGE TO HP / IP CASING INSULATION
IMPROPER ROLL CHECK OF HP/IP AND LP CASINGS
POOR BUMP CHECK
POOR LIFT OF JOURNAL IN BEARINGS
HIGH DIFFERENTIAL TEMP. OF TURBINE CASING
POOR SETTING OF OIL CATCHERS/SEALS
FOREIGN MATTER IN STEAM FLOW PATH
INADEQUATE MOTIVE POWER
EXCESSIVE PIPE PULLS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
BARRING GEAR STOPPAGE : RECOMMENDATIONS / ACTION TAKEN
REFER TROUBLE SHOOTING CHART
INTRODUCTION OF MODIFIED GLAND STEAM SYSTEM
FOR CENTERING & ROLL CHECK OF HP & IP TURBINE WITH TIP TO
TIP GLAND SEALS REF. TECH. CIRCULAR X-74 DATED 6TH NOV’2002
ADJUST POOR BUMP CHECK OR CONSULT BHEL
CHECK ROTOR SYSTEM CAN BE ROTATED EASILY BY HAND
CHECK MACHINE COMES TO AUTO BARRING
CHECK SPEED AT FULL BARRING AND COMPARE WITH PROTOCOLS
ENSURE PROPER INSULATION OF HP & IP CASING
REPLACEMENT OF LUBRITE PACKER WITH HIGH TEMPERATURE
MODIFIED PACKERS
BELLOWS BEING INTRODUCED IN LP FRONT AND REAR GLAND STEAM
SUPPLY AND LEAK OFF LINE
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
HIGH HPF SHAFT VIBRATIONS : PROBABLE REASONS
HIGH COUPLING RUNOUT / SWING CHECK
HIGH SLOW ROLL CHECK VALUE
UNEQUAL / DISTORTED RADIAL CLEARANCE
BAD CENTERING / ROLL CHECK
JAMMED SEAL SEGMENTS
ROTOR UNBALANCE
ANY MAJOR WORK DONE ON LP / GEN ROTORS, WHICH MAY HAVE
CAUSED ROTOR SYSTEM UNBALANCE
BAD BEARINGS
HIGH ROTOR RUN OUT AT JOURNAL / GLANDS
HIGH RUN-OUT / DENT MARKS AT THE LOCATION OF SHAFT
VIBRATION PICK-UP
POOR ALIGNMENT / POOR LOADING OF BEARINGS
OIL WHIRL CONDITIONS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
ANALYSE THE VIBRATION AND OPERATIONAL DATA
CHECK BEARING ASSEMBLY, ALIGNMENT, COUPLED RUN OUT,
ADJUSTMENT OF STEAM PATH
CROSS MATCHING OF HP / IP / LP ROTOR COUPLING FACES AT BHEL
WORKS
CHANGE IN THE AXIAL POSITION OF SHAFT VIBRATION PICK-UP DUE
TO HIGH SPOTS IN PRESENT LOCATIONS OF PICK UP
SLOW / RATED SPEED BALANCING
ENSURE PROPER FUNCTIONING OF SEAL SEGMENTS
PERIODIC SETTING OF SPRING LOADED TG DECK
INCREASE IN BEARING HEIGHTS, IF OIL WHIRL PRESENT AND
BEARING TEMPERATURE DISTRIBUTIONS NOT OK
HIGH HPF SHAFT VIBRATIONS : RECOMMENDATIONS / ACTION TAKEN
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
OFF LINE METHOD•Water fill test or vacuum tightness test•Steam pressurization test.
ON LINE METHOD• With the help of Helium Leak Detection Instrument
VARIOUS METHOD OF DETECTING AIR INGRESS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
WATER FILL TEST : NEW INITIATIVES / GUIDELINES
RECENTLY, BHEL – HARIDWAR HAS ISSUED GUIDELINES MENTIONING
THAT FROM SIMHADRI ONWARDS, ALL CONDENSERS OF 210 / 250 / 500
MW ARE DESIGNED TO WITHSTAND WATER FILL TEST UPTO LP BLADE
TIP. THIS WILL HELP IN DETECTING ALL MOST ALL AIR INGRESS POINT
NO FALL IN WATER LEVEL IN 24 HOURS SHALL INDICATE
SUCCESSFUL COMPLETION OF WATER FILL TEST
IN CASE OF FALL IN LEVEL, HIDDEN AIR INGRESS POINTS NEEDS TO
BE TRACED BY ELIMINATION PROCESS.
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
STEAM PRESSURISATION TEST IS CONDUCTED TO FIND OUT
LEAKAGES IN THOSE AREAS WHICH WILL REMAIN UNDER VACUUM
AND NOT COVERED IN WATER FILL TEST / VACUUM TIGHTNESS TEST.
STEAM PRESSURISATION OF VACUUM SYSTEM IS DONE IN AN
ABSOLUTELY COLD MACHINE AND PIPING SYSTEM.
STEAM PRESSURIZATION TEST INVOLVES FOLLOWING 3 STEPS:
STEP 1 : - CONDUCT WATER FILL TEST AND ENSURE THERE IS NO
FALL IN WATER LEVEL FOR 24 HOURS.
STEP 2 :- PREPARATION OF THERMAL SCHEME OF TURBINE FOR
STEAM PRESSURISATION.
STEP 3 :- CONDUCT STEAM PRESSURISATION OF VACUUM SYSTEM.
STEAM PRESSURIZATION TEST
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
CONDENSER
HELI LEAK DETECTOR
VACUUM PUMP
AIR EXHAUST
STEAM + AIR
SAMPLE LINE
HELIUM LEAK DETECTION TEST : SCHEME FOR DETECTING AIR INGRESS
HELIUM GAS SPRAY ON SUSPECTED AIR INGRESS POINTS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
COMPARISON OF STEAM PRESSURISATION TEST AND HELIUM LEAK DETECTION TEST
TEDIOUS EXERCISESIMPLE PROCEDURE5.
BULKY AND DELICATE INSTRUMENT
REQUIRE SYSTEM PREPAREDNESS PRIOR TO CONDUCT THE TEST
4.
CAN BE DONE AT LOADCAN BE DONE ONLY WHEN MACHINE IS COLD
2.
CAN DETECT BROAD AIR INGRESS AREA
CAN PINPOINT THE SOURCE OF AIR INGRESS
1.
REQUIRES HELIUM GAS WHICH IS NOT READILY AVAILABLE AT MANY POWER STATIONS
REQUIRE STEAM AND WATER 3.
HELIUM LEAK DETECTION TESTSTEAM PRESSURISATION TESTS.N
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
HIGH AXIAL SHIFT / DIFFERENTIAL EXPANSION
MS / HRH STRAINER CHOKING
OIL STARVATION
OVERSPEEDING OF TURBINE
OTHER PROBLEMS FACED IN KWU MACHINES
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
SPRING LOADED TG DECK : ADVANTAGES
MAJOR CORRECTION IN CATENARY OF MACHINE BY ADJUSTMENT
OF SHIM PROVIDED IN SPRING ASSEMBLY
REDUCTION IN COST OF CIVIL STRUCTURE
BETTER LAYOUT
ISOLATION OF TG DECK AND COLUMN WHICH WILL AVOID
VIBRATION PROBLEM IN TG COLUMN AT ANY TIME
EFFECT OF SETTLEMENT OF FOUNDATION COLUMN CAN BE
MINIMIZED FOR CATENARY DISTURBANCE
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
INCREASE IN ERECTION CYCLE TIME
INCREASE IN OVERHAULING PERIOD
COST OF SPRING ELEMENTS AND ITS INSTALLATION COST
SPRING LOADED TG DECK : DISADVANTAGES
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
USE OF CONVENTIONAL FOUNDATION AS STANDARD PACKAGE
FOR NON-EARTH QUAKE PRONE ZONE.
CUSTOMER WHO OPTS FOR SPRING LOADED TG FOUNDATION
SHOULD BE INFORMED OF INCREASE IN CYCLE TIME FOR
ERECTION AS WELL AS OVERHAULING.
SPRING LOADED TG DECK : BHEL’S RECOMMENDATIONS
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
TO DETERMINE LEVEL OF DEGRADATION IN THE UNIT
TO IDENTIFY AREAS OF DEFICIENCY
TO PLAN THE SCOPE OF WORK FOR NEXT OVERHAUL
TO PLAN THE SPARES REQUIRED IN THE NEXT O/H
TO PLAN THE MOBILISATION OF MAN, MACHINE, TOOLS AND TACKLES
TO PLAN FOR SPECIAL STUDIES TO BE CARRIED OUT IN THE NEXT
SHUTDOWN
AIM OF PRE – OUTAGE SURVEY
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
(A) Engineer from Turbine / Generator Group of PSTS (HQ) {LEADER}
(B) Field Engineering Service Engineer from Steam Turbine /
Turbogenerator Department from BHEL – Haridwar / Hyderabad /
Bhopal
(C) Service Engineer from Regional Service Centre
(D) Engineer from Regional Spare Business Group
(E) Vibration Engineer in case, the machine has some history of
vibration problem
Note:- After the survey, the team may recommend the visit of additional
experts to the site depending upon the problem / investigation
needed by the machine on case to case basis.
TEAM MEMBERS OF PRE – OUTAGE SURVEY
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
CHECKS TO BE CONDUCTED DURING PRE-OUTAGE SURVEY
CHECKS DURING THE RUNNING OF POWER STATION
CHECKS DURING THE SHUTTING DOWN OF THE MACHINE
STUDY OF PAST HISTORY OF THE PLANT
PRESENT AVAILABILITY OF SPARES WITH CUSTOMER
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
OPTIMAL APPROACH
SHORTER MAINTENANCE PERIOD BY ADVANCE PLANNING FOR
SPARE CONSUMPTION
PROVIDES LEAN TIME TO CUSTOMER FOR PROPOSAL
MOVEMENT / SANTIONING OF FUNDS
EDUCATION TO CUSTOMER WRT NEW PRODUCT , NEW
PHILOSOPHY, NEW FAILURES ETC.
PROVIDES FLEXIBILITY TO POST PONE THE SHUTDOWN
DEPENDING UPON CONDITION OF MACHINE
BENEFITS OF PRE – OUTAGE SURVEY FOR CUSTOMER
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
RUN THE COMPONENT.
o FOR HOW LONG ?
o WITH WHAT PRECAUTION ?
REPAIR OF THE COMPONENT
o HELP IN FINALISING SCOPE OF WORK DURING O/H
REPLACEMENT OF THE COMPONENT
o ORDER FOR SPARES WITH OEM TO AVOID DELAYS
DECISIONS OF PRE – OUTAGE SURVEY
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
ADVANCED CLASS STEAM TURBINE BLADES FOR IMPROVED EFFICIENCY
TODAY DESIGNER HAS ACCESS TO CALCULATION METHODS, WHICH VERY REALISTICALLY REPRESENT THE FLOW IN A TURBINE. THESE FLOW CALCULATION METHODS ARE USED TO OPTIMISE BLADE DESIGN FROM HP TURBINE THROUGH TO THE LP TURBINE. MOST OPTIMUM TX PROFILE BLADES GIVE HIGHER EFFICIENCY IN TODAY’S STEAM TURBINES. THREE DIMESIONAL BLADES (3DS BLADES) ARE IMPLEMENTED IN HP AND IP TURBINES TO REDUCE SECONDARY FLOW. TWISTED BLADES WITH INTEGRAL SHROUD ARE USED TO REDUCE THE INCIDENCE FLOW LOSSES AND FURTHER INCREASE EFFICIENCY.
IN LP TURBINE FINAL STAGES, CURVED STATIONARY BLADES (BANANA BLADES) ARE IMPLEMENTED TO POSITIVELY INFLUENCE THE DEGREE OF REACTION AND TO PREVENT FLOW SEPARATION AT THE HUB. THE OUTER PORTIONS OF THE FINAL STAGE MOVING BLADES HAVE BACKWARD LEANING PROFILES TO ACHIEVE HIGH PROFILE EFFICIENCIES. THE SIMULATION OF UNSTEADY FLOW IN THE TURBO-MACHINERY IS A CHALLENGING TASK AND CURRENT RESEARCHES ARE DIRECTED AT CFD MODELING TO SIGNIFICANGLY IMPROVE AERODYNAMIC PERFORMANCE OF THE BLADING.
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
HIGH PRESSURE ELECTRO-HYDRAULIC GOVERNING SYSTEM FOR STEAM TURBINES
HIGH PRESSURE ELCTRO HYDAULIC ACTUATION (EHA) SYSTEM COUPLED WITH DIGITAL CONTROL SYSTEM PRESENTS SIGNIFICANT ADVANTAGES OVER THE CONVENTIONAL LOW PRESSURE SYSTEM. IT IS COMPACT IN SIZE, PTOVIDES QUICKER RESPONSE, BETTER SUPERVISION, AND HIGHER LEVEL OF REDUNDANCY AND IS EASIER TO MAINTAIN. HIGH PRESSURE ACTUATION SYSTEM CAN BE APPLIED FOR MAIN, REHEAT AND BYPASS VALVES FOR STEAM TURBINES OF VARIOUS RATINGS. HYDRAULIC ACTUATORS, POWER SUPPLY UNIT, THE ELECTRICAL CONTROLLER AND THE PROTECTION SYSTEM ARE BRIEFLY DESCRIBED IN THIS PAPER.
BHEL HAD ALREADY INTRODUCED HIGH PRESSURE EHA SYSTEM IN HP & LP BYPASS SYSTEM FOR FARIDABAD (NTPC) & DVB COMBINED CYCLE POWER PROJECTS. THIS SYSTEM IS WORKING SATISFACTORILY AT THESE POWER STATIONS. PRESENTLY, BHEL IS IN POSITION TO OFFER HIGH PRESSURE EHA SYSTEM FOR TURBINE BYPASS OPERATION FOR CONVENTIONAL & CCP TURBINES OF ANY RATING. BHEL IS ALSO GEARING ITSELF FOR OFFERING EHA BASED SYSTEM FOR MAIN STEAM TURBINE VALVES.
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
HIGH PRESSURE ELECTRO-HYDRAULIC GOVERNING SYSTEM FOE STEAM TURBINES
THE HIGH-PRESSURE ELECTO-HYDRAULIC GOVERNING SYSTEM ALONGWITH THE DIGITAL CONTROLS OFFER THE FOLLOWING ADVANTAGES:
QUICKER RESPONSE
PRECISE CONTROLAND EASE OF ADJUSTMENT
BETTER SUPERVISION AND HIGHER REDUNDANCY
SIMPLIFIED PLANT LAYOUT DUE TO OVERALL CONPACT SIZE
EASE OF CHANGING CONTROL VALVE SEQUENCE
BETTER INTERCONNECTION WITH OTHER SYSTEMS
CONTROL OIL PIPING REDUCED TO LARGE EXTENT
GOVERNING AND BYPASS RACKS NOT REQUIRED
OPERATION AND MAINTENANCE ARE RELATIVELY EASY
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
STEAM TURBINES WITH SUPER CRITICAL PARAMETERS
MODERN SOCIETY’S CONCERN FOR POLLUTANT EMISSIONS FROM THERMAL POWER PLANT AND EVER INCREASING FUEL COSTS ARE TWO DRIVING FORCES FOR DEVELOPMENT OF MORE EFFICIENT POWER PLANTS. EVERY PERENTAGE POINT INCREASE IN THERMAL EFFICIENCY REDUCES POLLUTANT EMISSIONS BY 2.5% AND ALSO SAVES 2.5% ON FUEL COSTS. POWER GENERATION IN INDIA IS DOMINATED BY SUB-CRITICAL 500MW SETS OPERATING AT 170 ATA / 537 0C / 537 0C AND 210 MW SETS OPERATING AT 150 ATA / 537 0C / 537 0C.
EVERY 50 ATA INCREASE IN MAIN STEAM PRESSURE OR EVERY 22 0C INCREASE IN MAIN AND REHEAT STEAM TEMPERATURE IMPROVES CYCLE EFFICIENCY BY 1%.
Super-critical parameters221.2 BAR (225.6 ATA) PRESSURE AND 374.15 0C TEMPERATURE IS
CALLED CRITICAL POINT OF WATER / STEAM BECAUSE AT THESE PARAMETERS WATER CHANGES TO STEAM PHASE INSTANTANEOUSLY (WITHOUT ANY LATENT HEAT OF EVAPORATION). THE STEAM TURBINES UTILISING MAIN STEAM PRESSURE ABOVE THIS CRITICAL PRESSURE ARE CALLED SUPER-CRITICAL TURBINES.Advantage
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
USE OF SS TUBES IN SURFACE CONDENSER FOR ENHANCED RELIABILITY
FOR CONDENSERS EMPLOYING SWEET WATER I.E. COOLING WATER OTHER THAN SEA WATER OR SALTY WATER (CONTAINING HIGH CHLORIDES), USE OF WELDED SS TUBES IS RECOMMENDED AS THE BEST MATERIAL FOR ITS SUPERIOR QUALITIES OF BETTER EROSION-CORROSION RESISTANCE, HIGHER RELIABILITY, LONGER LIFE AND LOWER CAPITAL AND MAINTENACE COST IN COMPARISON TO NON-FEROUS TUBES LIE ADMIRALTY BRASS, ALUMINIUM BRASS OR CUPRO-NICKEL WHICH WERE CHOSEN AS THE TUBE MATERIALS FOR POWER PLANT CONDENSRES IN THE PAST AS PER TRENDS AND TECHNO-ECONOMICS PREVAILING THEN.
BHARAT HEAVY ELECTRICALS LIMITED
N.K. BANSAL, AGM (T)
FAST COOLING OF TURBINE TO REDUCE THE COOLING DOWN TIME
ALWAYS KEEP MANUAL VACUUM BREAKER OPEN
WHENEVER MACHINE WAS SHUTDOWN FOR LONG PERIOD, DRAIN
THE HOTWELL
PRIOR TO START OF OIL PUMPS, RAISE THE OIL TEMPERATURE