CYCLE TIME REDUCTION -

VIJAYAWADA 1 X 500 MW

EXPERIENCE

BOILER HYDROTEST IN RECORD 7 MONTHS AND 18 DAYS . FOLLOWING DELAYS AFFECTED DRUM

LIFTING SCHEDULE BY 190 DAYS . DELAYS IN MOBILISATION OF HIGH

CAPACITY CRANES . INCESSANT RAINS AND UNFAVOURABLE

SOIL CONDITIONS AFFECTED MATERIAL FEEDING AND TRANSHIPPMENT .

DELAY IN CONTRACT AWARDENCE DELAY IN MATERIAL RECEIPTS .

BOILER HT……… contd

COURSE CORRECTION

THE ABOVE PERIOD WAS UTILISED TO REORGANISE AND REWORK THE FURTHER PLANS . PLATFORMS AND ROOFING COMPLETED TO ENSURE

UNINTERRUPTED WORK . SITE ENSURED COMPLETION OF ALL WELDED BEAMS,

ROLLED BEAMS AND STRUCTURES . BOILER ROOF WAS TOTALLY COVERED TO FACILIATATE

UNINTERRUPTED WORK . CROWN PLATE ASSEBLIES AND BUCKSTAY ASSEBLIES

WERE MADE READY FOR IMMEDIATE LIFTING WHEN THE CRANE ARRIVED .

BOILER HT …contd ALL PLATFORMS IN THE INNER CAVITY

COMPLETED TO ENSURE WELDING WORKS MAINTAINED CONTINUITY .

INTERACTION AND FOLLOW UP WITH BHEL TRY FOR DESPATCH OF MATERIALS AS REQD IN TIME .

DETAILED PLANNING WITH SUB CONTRACTOR AND A DETAILED WORK SCHEDULE AND REQUISITE SKILLED MANPOWER AND TOOLS AND PLANTS ENSURED.

THE PERCENTAGE OF REPAIRS CARRIED OUT WAS LESS THAN 0.03% AND THIS REASULTED IN SAVING OF TIME AND RESOURCES.

HYDRAULIC TEST TO LIGHT UP

DMCW SYSTEM

BOTH SG &TG DMCW SYSTEMS MADE READY TOTALLY AND DMCW AND ACW SYSTEMS INTERCONNECTED AT PHE END AND FLUSHED BY RUNNING ACW PUMP WITH CLARIFIED WATER OF 1000TPH

DUCT LEAK TEST

COMPLETED FOR ALL DUCTS OF FLUE GAS AND SECVONDARY AIR EXCEPT PRIMARY AIR

WIND BOX TOTAL F.G DUCTS & SEC DUCTS EXCEPT ID B FAN

CONNECTION COMPLETED

ESP

ALL PASSES OF ESP MECHANICAL READINESS WITH LEAK TESTS COMPLETED

BOTH FD FANS AND ID FAN -A RUN AND GD TEST COMPLETED BEFORE LIGHT UP INTERLOCKS

ID FAN B –CUSTOMER FOUNDATION NOT CAST TILL BOILER LIGHT UP.

INSULATION

FOLLOWING DUCTS INSULATION COMPLETED BEFORE LIGHT UP -

ALL GAS DUCTS ALL SECONDARY AIR DUCTS . BOTH FD FANS ACOUSTIC INSULATION

COMPLETED . TOTAL BOILER INSULATION –AFTER

COMPLETION OF FURNACE LEAK TEST. ALL FUEL,WATER AND STEAM SIDE DRAINS

INSULATED IN A PHASED MANNER BEFORE LIGHT UP .

STEAM FLUSHING OF AUX LINES OF BOILER AND PREBOILER SYSTEM

THE PRESENT UNIT IS A STAND ALONE UNIT LIKE ANY OTHER GREEN FIELD PROJECT

A SEPARATE STEAM LINE OF 200 NB -700MTRS LONG WAS LAID AND STEAM FROM EXISTING UNIT WAS DRAWN AND FUEL , ATOMISING LINES,APRDS HEADERS WERE STEAM FLUSHED .

THE SAME STEAM WAS USED FOR STEAM FLUSHING OF ENTIRE PREBOILER SYSTEM ALSO

BEFORE EDTA CLEANING . DE-AERATOR WAS CHARGED AND FOLLOWING

LINES FLUSHED . FEED WATER SYSTEM . CONDENSATE SYSTEM . DRIP SYSTEM . EXTRACTION . PEGGING STEAM . AUXPRDS HT&LT,CRH-APRDS . HP HTRS WATER SIDE(5A,5B,6A&6B) . A SEPARATE PACKAGE BOILER CAN BE

INSTASLLED TO REDUCE CYCLE TIME

STEAM FLUSHING OF AUX LINES OF BOILER AND PREBOILER SYSTEM

STEAM BLOWING

H.T EST OF REHEATER ,CRH AND HRH LINES COMPLETED BEFORE COMMENCEMENT OF 1ST STAGE ST.BLOWING .

TEMPRORARY LINES ERECTED FOR BOTH STAGES BEFORE COMMENCEMENT OF STEAM BLOWING .

INSULATION OF LINES COMPLETED . TOTAL TIME TAKEN FOR SB START TO FINISH IS

13 DAYS. ALL THE AUX LINES ALSO STEAM BLOWN .

TURBINE AND GENERATOR

TOTAL INSTRUMENTATION OF LUB OIL, JACK OIL AND SEAL OIL SYSTEM COMPLETED AND INTERLOCKS LOGICS AND PHYSICAL OPERATIONS MADE READY FROM CONTROL ROOM BEFORE BARRING GEAR.

CONTROL FLUID PIPING FLUSHING COMPLETED ON 20-03-09

DECK FLOATING AND ALIGNMENT DECK FLOATING ,FINAL ALIGNMENT, COUPLING

BOLT FIXING AND STRETCHING ,SWING CHECK , ROLL CHECKS, HORN DROP TEST AND BUMP CHECKS ALONG WITH INSULATION COMPLETION AND BARRING GEAR WITHIN

14 DAYS FROM DECK FLOATING START

A SURFACE GRINDER WAS INSTALLED AT TURBINE FLOOR TO EXPEDITE KEYS MACHINING

WITHIN THE 14 DAYS PERIOD CONDENSOR FILL TEST AS WELL AS GOVERNING CHARACTERISTICS WERE ALSO COMPLETED

CONDENSOR FILL TEST

DE-AERATOR OVERFLOW AND DRAINS WERE DIVERTED FROM UFT TO SDFT, HOTWELL MAKE UP AND CONDENSOR CW WATER BOX DRAIN WERE TEMPORARILY CONNECTED TO FILL THE CONDENSOR FASTER. FILLING COULD BE DONE IN 4 HOURS.

FILL TEST WAS COMPLETED DURING KEYS FIXING ALL 3 CEPS AND BOTH THE VACUUM PUMPS WERE

OPERATIONAL FROM CONTROL ROOM BEFORE FIL L TEST

ALL GLAND SEALING LINES WERE COMPLETED IN ALL RESPECTS.

PROBLEMS AND CONSTRAINTS

MANY HIGH PRESSURE VALVE GLANDS FAILED AT DIFFERENT STAGES DURING HT OF BOILER.FW HT,BOILER HT DELAYED BY 15 DAYS EACH

ALL DMCW PUMPS (BOTH SG AND TG) SEALS FAILED WITHIN 2 MONTHS OF OPERATIONS BECAUSE OF SEALS FAILURE.

DIFFERENT SEALS ARE INSTALLED

CUSTOMER CIVIL FRONTS FOR PA FANS AND ID FAN B DECKS WERE DELAYED.GENERALLY ALL CIVIL AND FONDATIONS FOR EQUIPMENTS,DUCTS,STRUCTURES WERE DELAYED AND OFTEN SITE HAD TO READJUST THEIR PLANS ACCORDING TO FRONT AVAILIABILITY.THIS RESULTED IN DIFFICULTIES AND DELAYS.

DURING RAINS WORKPROGRESS WAS AFFECTED DUE TO LACK OF PROPER ACCESS AND SLUSHY CONDITIONS

PROBLEMS AND CONSTRAINTS

CW AND ACW SYSTEMS WERE DELAYED.ACW NON AVAILIABILITY AFFECTED TG INSULAYION AND INSTRUMENT AIR AVAILIABILITY

ACW CHARGED THROUGH COOLING TOWER ONLY BEFORE STEAM BLOWING BY CUSTOMER

CW PUMPS WERE RUN BY CUSTOMER ONLY DAYS BEFORE DECK FLOATING

ACW WAS SHUT DOWN AFTER STEAM BLOWING BY CUSTOMER TO MAKE READY CW SYSTEM.HENCE IINST AIR WAS NOT AVAILIABLE AND HENCE DELAYED TURBINE INSULATION

INNNOVATIONS AND IMPROVEMENTS

ERECTION OF PLATFORMS INSIDE TO INCREASE WELD JOINTS OUTPUT.

DUCT LEAK TEST WITH BLOWERS EVEN BEFORE FANS WERE READY

STEAM FLUSHING IN STEAD OF DETERGENT FLUSHING TO MINIMISE WORK ,TO SAVE TIME ,OPERATIONAL CONVENIANCE,PHASING OF WORK TO THE REQUIREMENTS AND LESS RESTORATION TIME.

LP BYPASS LAYOUT MODIFICATION BEFORE ERECTION.

HP BYPASS MODIFICATION BY SITE.

INNNOVATIONS AND IMPROVEMENTS HP BYPASS OIL LINES ERECTION AND OIL

SYSTEM COMPLETION ALONGSIDE PIPELINE AND VALVES ERECTION,TOTAL COMPLETETION IN 7 DAYS INCLUDING ERN,OIL FLUSHING AND REMOTE OPERATION.

COMPLETION OF GD TEST OF ESP BEFORE BOILER LIGHT UP.

TDBFP STEAM LINES AND FEED WATER LINES REROUTING FOR IMPROVEMENTS

TOTAL FUEL OIL SYSTEM COMPLETION AND ALL CC PUMPS COMMG AND GD TEST OF ESP BEFORE LIGHT UP.

BOTH FD FANS ERCTION AND COMMG TOGETHER.

SUGGESTIONS REUSABLE HOSES WITH ADDITIONAL FLANGES

TO SIMPLIFY CONTROL FLUID FLUSHING IN TG AND TDBFPS.

TEMPORARY STEAM HOSES DURING ERECTION FOR CLEANING AND THERMAL SHOCKS.SUCH HOSES ARE EMPLOYED IN REFINERIES

NASH PORTABLE TEST KIT. SURFACE GRINDER IS TO BE USED DURING FINAL

ALIGNMENT AND PACKERS MACHINING AFTER DECK FLOATING.

AIR EJECTORS FOR WATER DISPOSAL

SUGGESTIONS

BLOWERS ATLEAST THREE NOS TO COMPLETE LEAK TEST WHILE DUCTS ERECTION AND BEFORE FANS MECHANICAL RUN

STEAM BLOWING DEVICE FOR IVS AND ESVS LIKE LP BYPASS VALVES OF CCI WHICH IS FAIL SAFE AND EASY TO USE