takniki darpan - issue 6[1]

7/31/2019 Takniki Darpan - Issue 6[1]

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EDITORIAL COM M ITTEE

CONTACTS & FEEDBACKS

M r. Dinesh Jawad e

Email : [email protected]. in

Phone: 0712 3048660

M obi le: 09423680639

PUBLISHED BY TSX/ PSW R FOR INTERNA L CIRCULATION ON LY

ISSUE NO. 06 AUG 201 0

Ref lect ion of t he achievements ..

Sh. R L RAN W AS

Sh. S N M AITI

EDITOR

Sh. TARSEM LAL

The statem ents and v iew s expressed in th is M agazine

are ent i re ly tho se of aut hors and not necessar i ly that of

the Organizat ion.

Cover p hoto graph:

Pow er Plant , NTPC, Kor ba

INSIDE

TITLE PAGE

M ESSAGE FROM GM (TSX& SAS) 1

GLIM PSES OF SITES 2

ISSUE SPECIAL - 6

ALL VOLATILE TREATM ENT OF BOILER

FEEDBACKS 13

M ESSAGE FROM GM (TSX) 37


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TECHNICAL SERVICES, BHEL-PSWR 1

MESSAGE FROM GM (TSX & SAS)... . . . .

Dear Colleagues,

I am very m uch del ighted to present you th e six th issue of Taknik i

Darpan, the technical magazine published by PSWR, Nagpur. So far,

w e have covered variet y of t opics start ing from tu be m il l , CFBC boilers

to renewab le energy and many more to come in the fo r thcoming

issues.

Sharing of experiences and knowledge by means of various

feedbacks w i l l not only avoid recurr ing problem s but a lso expand t he

know ledge base of every engineer wo rk ing in power p lant , which w i l l

result in t im e saving. How ever, in spit e of kno w ing al l th ese, we are not

shar ing the feedbacks amongst us as there was no proper forum

available. Rout inely, w e face many pr oblem s and also resolve t hem at

si te level, but the same is not comm unicated t o o thers. I request each

indiv idual to spare f i f teen m inute t ime dai ly and m ake a habi t to record

th ese problem s in dai ly d iary w hich w i l l becom e consol idated feedback

from each indiv idual . And no w, these feedbacks can be shared to thelarger sect ion o f th e engineers th rough Takniki Darpan.

Hence, once again I request you t o generou sly share th e feedbacks,

even if i t is very small in nature, so that everybody in BHEL wil l get

benef i ted.

W ith w arm regards and best w ishes.

R. L. Ranw as

General M anager (TSX & SAS)

BHEL, PSW R (HQ)

Nagpur


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GLIMPSES OF THE SITES

STATUS OF THE SITES UND ER COM M ISSION ING:

1. NSPCL BHILAI (2 x 250M W )

Uni t No.01:

A. At present , un i t is running at var ious loads depending on load requirement and coal availab i li ty .

B. PG Test o f TG comple ted .

Uni t No . 02:

A. At present , un i t is running at var ious loads depending on load requirement and coal availab i li ty .

B. PG Test o f TG comple ted on 05 /08 / 2010.

2. TATA TROM BAY (1 x 250M W )

A. PG Test of Boi ler, TG and ESP com pleted.

B. At present , un i t is running at var ious loads depending on load requirement and coal availab i li ty .

3. M AHAGENCO PARAS (1 X 250M W AND 1 X 250M W Extn.)

Uni t No . 02:t h

A. Synch r on isat i on w i t h coal f ir i ng done on 18 Feb 2010 .th

B. U n it a ch ie ve d f u ll lo ad o n 27 M a r 2 01 0.

C. Un i t is gener at i ng a round 200 M W load .

D. BFP hydraul ic coupl ing bear ing tem perature r ise problem resolved.

E. Turb ine o i l coo le r bypassing p rob lem reso lved .

F. Un i t i s unde r t r i al ope ra t ion .

4. PARLI (1 X 250M W AND 1 X 250M W Extn . )

Uni t No . 01:

A. Un i t i s runn ing sm ooth ly a t fu l l load w i th CM C in serv ice.

Uni t No . 02:t h

A. Un i t ach ieved f u ll load on 10 Feb . 2010 .

B. M ajor pending p oints l ike comm issioning of STLD system , UCP, Sensors of smart w al l b lowers,

Aut o-synchro nizer, LSR, al l pr int ers, ATRS com pleted dur ing t he shut dow n.

C. Un i t r unning at 250 M W load w i t h CM C in se r vi ce .t h

D. Tr ial operat ion , Com ple ted on 30 Ju ly,2010.

TECHNICAL SERVICES, BHEL-PSWR 2GLIMPSES OF THE SITES


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E. PG test p repara t ion under p rogress.

5. IOCL, BARODA (2X33 M W )

Uni t No. 01:

A. FSNL ach ieved on 10 .08 .2009.

B. Un i t synchron ised on 08 .10 .2009.

C. HRSG hydro test comp le ted on 15 .10 .2009.

D. HRSG ABO achieved on 04.01.2010.

E. Safe ty valve f loa t ing comple ted on 13 .02 .2010.

F. Fu l l l oad ach ieved on 30 /03 /2010.

Uni t No. 02:

A. FSNL ach ieved on 30 .03 .2010.

B. Un i t synchron ised on 31 .03 .2010.

C. Un it unde r shu t down fo r at t end ing t he pend ing wo r ks.

6. KUTCH LIGNITE (1 X 77M W )

A. PG Test preparat ions under progress.

B. Pend ing po in ts a re be ing a t tended.

7. SULEM ANIYAH, IRAQ (4 X123M W, FR9)

Uni t No 04:t h

A. Un it Synch r on ised on 26 Feb . 2010 .t h

B. Re l iab il i t y run test comple ted successfu l ly on 28 M ar. 2010.

C. Representat ives of PSW R visi ted to at ten d pending points.

8. SLPP M ANGROL (2 X 125M W PHASE II)

Uni t No. 03:t h

A. Un it ach ieved f u ll load on 12 Ap r. 2010 .

B. U n it i n ru n n in g at 1 0 0 t o 1 25 M W l oad .

Uni t No. 04:th

A . U n it sy nch r on ise d o n 25 M a r 2 01 0.rd

B. A ch ie ve d f u ll lo ad o n 23 A pr 2 01 0.

C. Present ly, un it i s runn ing a t 120 -130 M W.


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9. M AHAGENCO BHUSAWAL (2 X 500 M W )

Uni t No.4 :

A. Dra inable hyd ro t est com p leted on 31 /03 /2010 .

B. Stator l i f t ing and p lacem ent completed on 27.07.2010. TG al ignment in progress

C. Sta t ion t ransfo rmer is ready fo r charg ing .

D. ESP/ VFD area t ray work and cabl ing in progress

E. Insta l lat ion o f SPBD and Tie bus duct und er progress

F. Insta l la t ion o f DCS pane l in con t ro l room comp le ted .

M ileston es Planned:

G. Star t up pow er com mission ing by 20 .08 .2010.

Crit ical Pendin g Issues:

H. SPBD M ater ia ls f rom BHEL Rudrapur.

I. TG packages f r om Har dwar.

J. Crit ical custo m er inp ut s l ike, AC PCR, AC VFD CR, FOPH to boiler pipe rack, Boiler o/ L to ESP ductfoun dat ions, ACW / CW pum p ho use building, Boiler to TG cable tray interconnect ions, PCR to ID fan

area pipe rack w ith t rays etc.

10. M AHAGENCO KHAPERKHEDA (1 X 500 M W )

A. Stat ion Transform er-5B w as charged on 12/ 04/ 10 at 18:38 hrs & kept charged for 24 hrs on no- load

condi t ion.

B. VFD Panels & VFD Transform ers have been erected.

C. Dry Type Transform ers, LTM SB, ACP & Electro nic Cont rol Panels for ESP have been erected.

D. Soot B lower M CC has been erected .

E. Cont rol Panels of Contro l Equip m ent Room l ike STRP-A/ B, GRP & DAVR have been erected.

F. Al l the contro l panels of Cont ro l Equipm ent Room have been erected except Gravim etr ic Feeder

Panels- 2 nos., Gen. End W indin g Vibrat ion Panel.

G. Cabl ing of HT SW GR to M AX DCS has been comp leted.

H. Cabl ing of M TM T/ C is in progress. M TM pads are being w elded by Boi ler M ech. JB's have been

erected.

I . Cab ling o f Drum Vents M OVs is in p rogress.

J. M ax DCS pane ls o f FOPH/CWPH have been erec ted .K. UPS, ACDB & Bat ter ies have been erected.

L. 24 V DCDB have been erected & Pow er cabl ing for one source has been done for a l l the m ax DCS

panels.

M . Lub o i l f lush ing o f ID , FD & APH comple ted .


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11. NTPC KORBA-7 (1 X 500 M W )t h

A . Bo il er li gh t ed u p on 2 8 Fe b 20 10 .st

B. EDTA clean ing com p le ted on 31 M ar 2010.t h

C. Detergent f lush ing o f bo i ler feed system comp le ted on 26 Apr. 2010.t h

D. St e am b lo w i n g co m p l et e d 4 A u g., 20 10 .

12. BORL, Bina

Uni t No. 1:

A. Ro l li ng o f t he t u r b ine achieved on 09 / 07 /2010.

B. Dynam ic t est i ng o f Gener ato r com p leted on 09 / 07 /2010.

C. Elect r ical overspeed o f tu rb ine demonst rated .

D. M a jo r p r ob lem w i t h Gener ato r Tr ansfo r m er at t ended .

E. Dead bus synchron iza t ion o f the Un i t ach ieved on 29 / 07 /2010.

F. Turb ine ro l ling p rob lem has been a t tended.

G. Coa l Fi r ing o f Un i t 1 p lanned by end August , 2010.

Uni t No . 2:

A. Tu r bovi so r y wo r k com p le ted.

B. A l l tu rb ine auxi l ia r ies remote t r ial w i th in te r locks comple ted .

C. Tu r b ine pu t on ba r ri ng gear on 31 /07 / 2010 .t h

D. Dead Bus synch r on isa t ioncom p le ted on 15 Aug. 2010 .

Cri t ical Issue s :

1. Inst rum enta t ion cab les f rom BHEL, Hyderabad.

Uni t No. 3:

A. 2 M VA stat ion Auxi l iary t ransform er (TR-64) has been charged.

B. Coo l ing tow er motors test ing has sta r ted .

v v v



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TECHNICAL SERVICES, BHEL-PSWR 6ISSUE SPECIAL - ALL VOLATILE TREATMENT OF BOILER

INTRODUCTION:

M odern therm al pow er p lants, st ressing on h igher avai lab i l ity , h igher re l iab i l ity , opt im al operat ion &

m aintenan ce costs, enhan ced l i fe of boi ler pressure part s and ease of op erat ion , advocate for str in gent

boi ler water chemistry dur ing operat ion. Also the feed water chemistry mainta ined dur ing the p lant

operat ion determ ines the am ount & type of depo si ts ins ide the boi ler tub es, which determ ines the po st

operat ional chemical cleaning and the intervals of cleaning. These necessitated the discontinuance of

coord inated phosphate t reatm ent for Boi ler w ater chemistry and advent of Al l Volat i le Treatm ent o f Boi ler

w ater for sub-cr i t ica l & super cr i t ica l cycles p lant operat ion. Also com bined w ater t reatment (CW T), a

phi losophy of t reat ing the conden sate w i th CPU and boi ler w ater w i th oxygen do sing, is a lso em erging as

an improved method for better l i fe cycles of al l pressure parts in the plant. Research and studies arecont inuing regard ing the in f luence of w ater chemistry over t he depo si ts and l i fe of pressure par t s of

therm al pow er p lants a l l over t he w or ld. BHEL has suppl ied f i rs t t im e uni t s operat ing on Oxygenated Water

Treatm ent m ode (2 X 250 M W ) to NSPCL, BHILAI.

PROJECT DESCRIPTION:

BHEL has execut ed 2 X 250 M W pow er pro ject at BHILAI for NSPCL, a joint vent ure p ow er ut i l i ty of SAIL

and N TPC on EPC basis except CHP and Swit ch yard. Salient feat ure s of t he Boil er and Plant are,

Type: Nat ural Circulat ion , Radiant Reheat , Tangent ial fir ing, Single

Drum , Dry bot to m & Balance draf t furnaceFuel: Pulverised coal

Raw w ater : Chlor inat ion t reatm ent

PT Plant : Chlor inat ion, Liquid Alum & Poly Alum inium Chlor ide t reatm ent in Clar i fuculator

DM w ater : RO plan t

Feed w ater: Liquid am m onia and Oxygen t reatm ent w i th Condensate Pol ish ing Uni t

CW system : Chlor inatio n, Sulph uric acid and Scale- inhibito r do sing

DM CW system : Caustic Lye t reatm ent

Pot able water:Hypochlor i te t reatm entBOPs: PLCs l inkage w ith m ain Cont rol Room by Opt ical Fibre Cabling

AHP: Dry f ly-ash hand ling w ith pressurized air conveying

: Furnace bot tom w i th HP w ater seal & w et ash handl ing system

ETP & STP: Ash w ater recovery system and p lant w aste w ater t reatm ent

M RS: Pneum atic p ressurized conveying system

ISSUE SPECIAL ALL VOLATILE TREATMENT OF BOILER

BOILER OPERATION W ITH AVT & CW T

Sh. V.NAVANEETHAKRISHNAN

UCM / BHEL Sit e, N TPC KORBA


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DESCRIPTION O F AVT & CW T:

All Volat i le Treatment is the method that keeps dissolved oxygen close to zero and suppresses

corrosion of t ubes. Rem oval of dissolved oxygen in the bo iler feedw ater is don e by dosing hydrazine at th e

CEP discharge and by d eaeration b efore t he suction of BFPs. For m aintaining pH o f Boiler w ater, am m onia is

dosed in th e condensate d ischarge, contrast to the convent ional phosphate dosing in t he bo i ler drum .

Com bined w ater t reatm ent is the pro cess of do sing am m onia to m ainta in boi ler w ater pH and dosing of

oxygen in very sm al l quant i ty (5 ppb to 20 ppb approx. & 50 ppb m ax. in a w eek) to achieve Hemat i t e layerinside th e tu bes. For Boi ler operat ion w i th AVT / CW T, h igh pur i ty of conden sate, feedw ater & Boi ler w ater,

for w hich CPU is provided in the scheme.

CW T adopt ed for therm al pow er p lant g ives hem at i te layer ins ide t he t ubes, w hich is f la t and dense,

compared to the convent ional magnet i te layer which is undulated. And the solubi l i ty of hemat i te is

extremely smal l compared to magnet i te , which conta ins re lat ive ly large magnet ic par t ic le causingundu lat ion scale form at ion o n t he sur face of the m eta l . Also du r ing Boi ler operat ion w i th CW T, the scale

generat ing speed on tubes comes down to hal f o f o ther t reatments, which resul ts in lesser post

operat ional chemical c leaning act iv i t ies. How ever for operat ing the un i t on CW T, h igh pur i ty of w ater to b e

m ainta ined w hich involves st r ingent m easures and c lose m oni to r ing of SWAS parameters a long w i th t he

operat ion of CPU. The operat ion loss of t herm al plant on accoun t of t ube fai lures, chem ical cleaning etc arereduced to t he tu ne of 20 to 95 % by adopt ing CW T.

Cont rol l ing t he dr um sil ica is don e by t he op erat ion of CPU in t he CEP discharge l ine. I f th e CPU is notready / comm issioned, Boi ler w ater s il ica levels are contro l led b y th e operat ion of CBD f rom Drum , leading

to w astage of boi ler w ater and addi t ional make-up of DM w ater.

In th e absence of CPU in serv ice in t he condensate l ine for contro l l ing si l ica, lo t o f DM w ater about 2003

M / Day is being used as m ake up t o t he system due t o op erat ion of d rum CBD, in BHILAI uni ts . Also l iqu id

amm onia be ing dosed in the system fo r ma in ta in ing the pH o f water. How ever fo r un i ts des igned fo r

Oxygenerated t reatm ent in feed system , Hydrazine do sing is not recom m ended for rem oving d issolved

oxygen. Only am m onia dosing for pH correct ion and Deaerat ion are recom m ended for u ni t o perat ion

w hich is cal led AVT (O), being fol low ed in BHILAI.

THE PARAM ETERS TO BE M AIN TAIN ED IN UN IT:

Fol low ing are the paramet ers to b e m oni tored and m ainta ined dur ing uni t operat ion w i th AVT (O),

I Dem ineral ized w ater (at DM Plant out let)

Param eters Values

1. Specif ic conduct ivit y (m icrom hos/ cm ) 0.15 (M ax)

2 . Speci f ic conduct iv it y (m ic rom hos/cm ) 1 .0 (M ax)at storage tank out le t ( including CO )2

3. Silica (as SiO , ppm ) 0.02 (M ax)2

4. Na + K , ppb , m ax 5 (M ax)

5. TOC (ppb , m ax) 300 (M ax)

6 . O xyge n Sat u r at e d


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III Boi ler w ater qual i t y - AVT (O)

1. pH at 25 deg C > 8.5

2. Cat ion conduct ivit y (m icrom hos/ cm ) 1.5 (M ax)

3. Sil ica (as SiO , ppm ) 0.13 (M ax)2

4. Ch lo r ide (as Cl, ppb ) 30 (M ax)

5. Su lphat e (as SO , ppb) 30 (M AX)4

6 . Oxygen (as O , ppb )

(No te: as m easured at dow ncom er ) NIL

IV Satu rated steam qual i t y- AVT (O)

1 . Co nd uct ivit y (m i cr om h o s/ cm ) af ter cat io n exch an ger 0 .20 (M ax)

2. Silica (as SiO , ppb) 20 (M ax)2

3. Sod ium (as Na, ppb ) 5 (M ax)V Super heated steam qu al i ty- AVT (O)

1 . Co nd uct ivit y (m i cr om h o s/ cm ) af ter cat io n exch an ger 0 .20 (M ax)

2. Sod ium (as Na, ppb ) 5 (M ax)

3. Silica (as SiO , ppb) 20 (M ax)2

4. Iron as Fe, ppb 20 (M ax)

5. Ch lo r ide (as Cl, ppb ) 3 (M ax)

6. Su lphate (as SO , ppb) 2 (M ax)4

VI Condensate qual i ty Hotw el l out let1 . Ca t ion conduct i v it y (m ic rom hos /cm ) 0 .20 ( M ax)

2. Silica (as SiO , ppb ) 20 (M ax)2

3. Oxygen (ppb ) 10 (M ax)

4. pH 9.0- 9.6

5. Iron (as Fe, ppb) 20 (M ax)

1 . co nd uct ivit y (m i cro m h os/ cm ) af ter cat io n exch an ger 0.2 0 (M ax)

2. Specif ic conduct ivit y (m icrom hos/ cm ) 4.0 - 11.0

3. pH at 25 deg C 9.2 - 9.6

4. Silica (as SiO , ppm ) 0.02 (M ax)2

5. Iron as Fe, ppb 20 (M ax)

6. Oxygen (ppb) 10 (M ax)

7. Ch lo r ide (as Cl, ppb) 3 (M ax)

8. Su lphate (as SO , ppb ) 2 (M ax)4

II Feed w ater qual i t y- AVT (O)


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AVT w i th & w i thout CPU

AVT w i th & w i tho ut CPU II

AN ALYSIS OF SAM PLES OF UNIT OPERATION :

Follow ing pictor ials i llustrate th e Fe pick up by t he feed w ater at var iou s locations of t he Regenerative cycle

in t he po w erplant op erat ion. I t is clear that w i thou t CPU, the Fe concentrat ion in the operat ing system

sam ple is m ore at al l locations, from CEP Dischrge to t urb ine inlet .


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LIM ITS OF DRUM PRESSURE:

Fol lowing graphs depict the l imi ts of drum pressures dur ing uni t operat ion wi th respect to the s i l ica,

chlor ides and sulph ate values from th e sam ples of Boiler w ater.

Cont rol o f Si l ica in Boi ler Wat er un der AVT (O)


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Cont rol of Sulph ate in Boi ler w ater un der AVT (O)

Cont rol of Chlor ide in Boi ler w ater un der AVT (O)


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CONCLUSION:

Thermal power plants operat ing on Supercr it ical cycles and Once through Boilers are general ly

operat ing on AVT mode / Oxygenerated t reatment , as the Turb ine operat ing parameters need st r ic t

contro l on steam pur i ty fo r safety of t urb ine b lades and bo i ler tubes. How ever p lants operat ing on sub-

cr i t ica l cycles also can operate w i th AVT / Oxygenerated m odes that provide h igh steam pur i t y for b et ter

operat ing condi t ions l ike low er s il ica levels and low er deposi ts in tubes. But the operat ion and m oni tor ing

of Steam and w ater samples at al l locatio ns in the Regenerative cycle to be d one r el igiously for achievingth e result s.

v v v

M r. V. Navaneethakr ishnan has joined in BHEL Trichy in M ay 1982 as Chargem an in QC

depar tm ent of Boi ler and auxi liar ies w i th DM E.He has com pleted AM IE (I) in 1983 inm echanical branch and jo ined as Engineer in PSWR in Jan 1989 at KHAPERKHEDA

Turn key project as Boiler Com m ission ing Engin eer.He has completed M BA (HR) f rom IGNOU New Delh i in 1993 and no w present ly

w orking as UCM at 1 X 500 M W NTPC Korba un i t 7


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TECHNICAL SERVICES, BHEL-PSWR 13SITES FEEDBACKS

FEEDBACKS

Tata Pow er Trom bay U#8 1 X 250 M W

FLUE GAS DESULPHURISATION PLANTShr i. V.K. Jhad e

M anager, Khaperkheda


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3. Equip m ent for FGD:

Equipm ent Detai ls

Type Wo rkin g+ Stan dby

1 ) BO OSTER FA N o n e

2) BUF Cont ro l o i l pum p t w o

3) BUF Seal air fan one+one

4) Sea w ater / booster pum p t w o+one

5) Aerat ion fan t wo

6) GGH one

7) GGH seal air fan one

8) GGH SOOT b low er one

9) GGH H.P & L.P. Pum p one+one

10) Seal air fan fo r in let dam per one+one


1. Boost er fan3

Capac ity 626890 m / hr

Ef f iciency 80%

Pow er consum pt ion 1125 kW

2. Sea W ater pum p3

Capac ity 3600 x 2 m / hr

Head 14 m

Eff iciency 85%

Pow er consum pt ion 320 kW

Sea water consum ptio n3

Scrubb ing 7200 m / h r3

M ixing & aerat ion 6200 m / h r3

Service w ater consum pt ion 20 m / hr


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22TECHNICAL SERVICES, BHEL-PSWR 16SITES FEEDBACKSTECHNICAL SERVICES, BHEL-PSWR

4. OPERATIONAL PARAM ETERS OF FGD

BOOST UP FAN NORM AL ALARM TRIP UNIT TIM E

DELAY

FAN BRG. TEM PERATURE 45 >80.0 >90 DEG C >10 S

BEARING ROOM TEM P 45 >80 >90 DEG C >10 S

HYDRAULIC ACTUATING ROOM TEM P 50 >80 >90 DEG C >10 S

DE BRG. 1& 2 TEM PERATURE 45 >80 >90 DEG C >10 S

NDE BRG. 1& 2 TEM PERATURE 45 >80 >90 DEG C >10 S

M OTOR BRG. TEM PERATURE 50 >80 >90 DEG C >10 S

M OTOR W DG. PHASE 1,2,3 TEM P 60 >105 >110 DEG C >10 S

FAN HOUSING VIBRATION 0.5 >9.6 >12.6 m m / S >10 S

M OTOR I/ B & O/ B BRG. VIBRATION 1 >9.6 >12.6 m m / S >10 S

BUF LO PRESSURE 5 8.8 m m / s >10S

PUM P NDE BRG. VIBRATION 2.74 >4.4 >8.8 m m / s >10SM OTOR I/ B BRG. VIBRATION 4 >4.4 >8.8 m m / s >10S

M OTOR O/ B BRG. VIBRATION 3.5 >4.4 >8.8 m m / s >10S

PUM P DE BRG. TEM PERATURE 45 >80 >90 DEG C >10S

PUM P NDE BRG. TEM PERATURE 46 >80 >90 DEG C >10S

M OTOR I/ B BRG. TEM PERATURE 45 >80 >90 DEG C >5S

M OTOR O/ B BRG. TEM PERATURE 46 >80 >90 DEG C >5S

M OTOR W DG. TEM PERATURE 70 >105 >110 DEG C >5S

PUM P RUNNING & DV CLOSED OPEN TRIP >30S.

SCAVENGING LOW LEAKAGE FAN 50 >90 >100 DEGC >10S

SW BP CURRENT 20 AM PERE

3SW BP FLOW EACH 3600


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LOGISTICSSEAL AIR FAN :-- I/ L DAM PER CLOSED, I/ L DAM PER SEAL AIR VALVE OPEN,

ALL SEAL AIR FAN STOPPED.:--- AUTO START.

I/ L DAM PER OPEN & I/ L DAM PER OF SEAL AIR FAN CLOSED & FAN RUNNIN G 50 DEG C,

AUTO PUM P A START COM M AN D OR >60S, PUM P B START.

BLOW ER O/ L AIR TEM PERATURE


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Rot or Speed:- Nor m al Speed 3 .0 R.P.M . Nom inal

Slow Spee d:- 0.5 R.P.M . No m inal

Bearing Lubrication :- Oil bath for bot h roto r bear ings.Top Steady Bearin g 15 litr es. (appr ox.)

Bott om Supp ort Bearing 30 l i t res. (approx.)

Grade ISO VG 1000 Synt het ic (M obil SHC639 or equ ivalent)

Gearbox Lubrication :- Oil bath for bot h Pr imary and Secondary Uni ts .

Cleani ng Devices:- Tw o-off fu l ly retractable Jetb low ers.

Location - One in each unt reated gas duct .

M edium - UTG In let : - Steam / HP / LP Water

U TG O ut l et : - St e am / H P W a t er

STEAM :- Availab le st eam supp ly p ressu re:- 20.6 bar g.

Operat ing p ressu re :- 8 bar g.

No . of N ozzles :- 6

Op erat in g f lo w :- q uant it y p er lan ce 3600 kg/ h r

Rot or spee d - 3.00 R.P.M .

Frequen cy :- Every 8 hou rs init ial ly.

Final f requency to be determ ined by o perator exper ience at s i te

HP WA SHING:- Hot End Cleaning Device (Untreated Gas Inlet Du ct)

Cold End Cleaning Device (Untr eated Gas Out let Duct) - On Load Cleaning

M edium : - Cold W ater.

Pressure at Inlet Flange :- 100b ar g.

No . of N ozzles :- 6 3Water Consum pt ion / Lance - 5 .7 m / hr

Rot or speed :- 0.5 R.P.M .

Frequency :- When no rm al soot b low ing

cannot m ainta in pressure drop below 1.5 t im es c lean rotor va lue.

LP WASHING:- Hot End Cleaning Device (Untreated Gas Inlet Du ct) -

Off Load Cleaning

M edium : - Cold W ater.

Pressure at In let Flange - 5 bar g.

No . of N ozzles :- 6

Radial Coverage :- 3098 m m (approx.)3

Water Consum pt ion / Lance : - 39 .6 m / hr

Rot or speed :- 0.5 R.P.M .

Frequen cy :- As foun d necessary w ith b oi ler of f load.



21/40


RATING ARE AS:- DESIGN/ M AX/ 50%TM CR RATING ARE AS:- DESIGN/ M AX/ 50%TM CR

M AX/ 50%TM CR M IN. M AX/ 50%TM CR M IN.

Rotat ion Speed rp m :- 3 .00 / 3 .00 / 3 .00 / 3 .00 Rotat ion Speed r pm :- 3 .00 / 3 .00 / 3 .00 / 3 .01

Flow Quant i t ies per Bo i ler (kg/ hour ) Flow Quant i t ies per Bo i ler (kg/ hour )

U nt r eat ed G as In 8 0 86 90 / 8 08 69 0/ 4 9 12 00 / 4 91 20 0 U nt r eat ed G as In 8 0 86 90 / 8 08 69 0/ 4 9 12 00 / 4 91 20 1

U n t re at e d Ga s O u t 8 2 48 1 8 / 8 2 41 3 0/ 5 0 32 2 6/ 5 0 37 4 6 U n t re at e d Ga s O ut 8 24 81 8 / 8 24 1 30 / 5 0 32 26 / 5 0 37 47

Tr eat ed Gas In 8 17 49 1/ 8 17 91 9/ 5 03 83 0/ 4 97 03 0 Tr eat ed G as In 8 17 49 1/ 8 17 91 9/ 5 03 83 0/ 4 97 03 1

Tr eat ed Gas O ut 83 29 51 / 8 32 95 1/ 5 1 32 94 / 5 06 40 8 Tr ea te d Ga s O ut 8 32 95 1/ 8 3 29 51 / 5 1 32 94 / 5 06 40 9

Treated Gas Recyc led Purge 18801/ 18319/ 11994/ 12052 Treated Gas Recyc led Purge 18801/ 18319/ 11994/ 12053

Treated Gas Recyc led Scavenge 12788/ 12154/ 9618/ 9752 Treated Gas Recyc led Scavenge 12788/ 12154/ 9618 / 9753

To t a l St a ck Fl o w rat e 8 0 1 3 62 / 8 0 2 4 78 / 4 9 1 6 82 / 4 8 4 6 04 To t a l St a ck Fl o w rat e 8 0 1 3 62 / 8 0 2 4 78 / 4 9 1 6 82 / 4 8 4 6 05

Leakage per Bo i ler (as % o f Unt rea ted Gas In le t Flow) Leakage per Bo i ler (as % o f Unt reated Gas In let Flow)

Unt reat ed t o Treat ed Unt reat ed t o Treat ed

Gas Leakage 0.46 / 0.44 / 0.49 / 0 .51 Gas Leakage 0.46/ 0 .44/ 0 .49/ 0.52

Tem perat u res (C):- Tem perat ures (C):-

Un t reat ed Gas In 135 .0/ 1 55.0/ 1 23.0 / 123.0 Unt reat ed Gas In 135.0/ 1 55.0/ 1 23.0 / 123.1Unt reat ed Gas Out 79.3/ 97.0/ 80.4/ 74.1 Unt reat ed Gas Ou t 79.3 / 97.0 / 80.4 / 74.2

Treat ed Gas In 30.0/ 46.4/ 45.8/ 33.6 Treat ed Gas In 30.0 / 46.4/ 45.8/ 33.7

Treat ed Gas Ou t 85.2/ 103.9/ 87.8 / 82.8 Treat ed Gas Ou t 85.2/ 103.9/ 87.8 / 82.9

Pressu res (m m W g):- Pressu res (m m W g):-

Unt reat ed Gas Sid e Unt reat ed Gas Sid e

Pressu re Dro p 55.5/ 59.1 / 39.0 / 38.6 Pressure Drop 55.5/ 59.1/ 39.0/ 38.7

Clean Clean

Plat e Plat e

Treat ed Gas Sid e Treat ed Gas Side

Pressu re Dro p 47.2/ 50.5/ 34.9/ 33.6 Pressure Dro p 47.2/ 50.5/ 34.9/ 33.7

Clean Clean

Plat e Plat e


Gas Dif feren t ial Gas Dif feren t ial

Ho t En d :- 2 85.0/ 285.0/ 190.0 / 190.0 Ho t End :- 2 85.0 / 285.0/ 190.0/ 190.1


Gas Dif feren t ial Gas Dif feren t ial

Co ld En d :- 182.2/ 175 .3/ 116.2/ 117.8 Co ld En d :- 182.2/ 175.3/ 116.2/ 117.9

Treat ed Gas Com posit ion (% b y vo lum e):- Treat ed Gas Com po sit io n (% b y vo lum e):-N it ro gen 71.946 / 7 1.946/ 7 2.298/ 7 6.028 Nit rogen 71.946/ 7 1.946/ 7 2.298/ 7 6 .029

Oxygen 4.400/ 4.400/ 5.860/ 6.170 Oxygen 4.400/ 4.400/ 5.860/ 6.171

Car bo n Dio xid e 13 .4 00 / 1 3.4 00 / 1 2.0 80 / 1 2.7 10 Car bo n Dio xid e 13 .4 00 / 1 3.4 00 / 1 2.0 80 / 1 2.7 11

Su lph ur Dioxid e 0.004/ 0 .004/ 0 .002/ 0 .002 Su lp hu r Dioxid e 0.004/ 0 .004/ 0 .002/ 0 .003

W at er Vapo ur 10.250/ 10.250/ 9 .760/ 5 .090 W at er Vap ou r 10.250/ 10.250/ 9 .760 / 5.091

Densi t y a t NTP kg /m :- 1 .3076 / 1 .3076 / 1 .3029 / 1 .3288 Densi t y a t NTP kg /m :- 1 .3076 / 1 .3076 / 1 .3029 / 1 .3289


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Pro t ect ions Alarm Tr ip

Fan bear ing t em perat u re >95deg Celsius >105deg Celsius

Fan v ib ra t ion >4 .5mm / s 9mm / s

Delta P across oi l f i l ter >5 bar

Lube oi l pressure low 20 bar

Lube oi l pressure >4 bar

Bearing tem peratu re


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Booster fan fi rst up sequence

M oto r NDE,DE Vib not h igh

Fan hou sing vibrat ion n ot h igh

Lube o i l pressure no t low

Out le t damper open

In le t dam per open

Seal pressure n ot < 4 b ar

M otor bear ing tem peratu re no t h igh

Booster fan bear ing tem perature not h igh

FGD PG TEST

FGD PG test w as carr ied ou t aft er com plet ion o f Boiler and TG PG test. FGD PG Test w as delayed due t o no n

avai lab i l ity of CW Pum p as wel l as low suct ion pressure and insuf f ic ient w ater f low thro ugh FGD booster3 3pum ps. (Sea water f low a t Booste r pum p in let i s 5800m / hr aga inst des ign rated f low is 7200m / hr )

Booster pu m p in let connect ion is g iven at condenser CW out le t p ipe.

W ith m ut ual agreem ent bet w een BHEL and TATA POWER, FGD PG Test carr ied ou t as it is cond it io n at unit

fu l l load 250 M W.

FGD PG test carr ied out on 25/ 03/ 10 f rom 1500 hrs to 1800 hrs at uni t fu l l load 250M W.

SO m easured at in le t o f FGD is 50.7ppm and at FGD out le t 4 .4ppm .2

As per test reading FGD SO rem oval eff iciency ism ore than 90%as design guarant y value is 90%.2

M r. VIRENDRA KUM AR JHADE obt ained B.E. Degree in M echanical Engineerin g from

Governm ent College of Engineering and Technolo gy, Raipur (Ravishankar University).

He join ed BHEL Pow er sector w estern region as Engineer Trainee in 1997. He h as w orked

in Technical services department in the area of Boiler commissioning. He has wide

experience in various types and capacity of boi ler commissioning l ike CFBC, AFBC,PURVERISED FUEL FIRED, STROKER BOILER et c.

He is w orkin g as M ANAGER, Technical Services, Boiler com m issionin g depart m ent .


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OBSERVATIONS:

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During f irst synchronizatio n of Paras-II, the air leak test value could n ot be achieved to below < 0.32 2

kg/ cm in 24 hrs w i th test a ir pressure of 4.0 kg/ cm . Subsequent to t he synchronizat ion, the a i r leak test

w as repeated and some m ore leakages w ere found in th e end seal area (along the bol ts) and in som e pipe2

w eld jo ints. Even af ter at ten ding those, the leak test va lue could not be brought do w n below 0.24 kg/ cm in2

24 hrs. It w as a constant drop of 0.02 kg/cm per hr.

ACTIONS:

Fol low ing operat ion point s were a lso scrut in ized but d id not resul t any im provem ent in t he leak test

value:2 2

Seal o i l DP- The DP w as reduced f rom 1.7 kg/cm to 1.3 kg/cm w i thou t any resul t .

Generator gas temp erature var iat ion dur ing day and n ight- Even af ter t ak ing temperature correct ion,2

the resu l t w as no t w i th in the perm issib le lim i t ( m ax 0 .05 kg /cm )Af ter lo t o f bra in storm ing, i t w as found out that there w as a i r leakage in the d iode w heel area. This

m eant t hat t he leakage was from th e CC (current carrying) bolt s of exciter. Considering th at i t w as a new

generator, any leakage in t he CC bolt area was not ant icipated .

The m atter w as referred to BHEL/ Hardwar for n ecessary act ion. BHEL/ Hardwar t echnician team w ith

requ ired spares ( O-r ing and adhesive), visited site and replaced t he dam aged / und er size O-r ings below

the seal p late and around t he CC bol ts m at ing sur face wi th seal p late t o at tend to t he problem .

GENERATOR AIR LEAK TESTShri. S. M andal

AGM (TSX), Paras Sit e


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OBSERVATION:

Before star t o f contro l f lu id f lushing, a ir leak test of contro l f lu id l ines w as done. For condu ct ing the a i r

leak test , o t her t han m any dum m ies, one dum my w as put in the d ra in l ine of t he govern ing rack ( ref f ig-1

below ). Lub o i l system f lushing w as com pleted and system w as in service w ith f resh oi l . Oil accum ulat io n inthe govern ing rack header w as not iced.

ACTION:

Since th e FRF system w as not start ed, th e source of o i l w as lub o i l only. After careful t racing, i t w as

conf i rm ed that the o i l was com ing f rom the vent l ine of th e pr im ary o i l l ine. As per th e scheme, in case ofFRF as control f luid and lub oi l for turbine bearings, the pr imary oi l l ine vent in the governing rack is

connected in to a separate header w hich w as term inated to the lub o i l d ra in h eader. In th is case, i t w as

observed that t here w as an extra vent l ine (see f ig-1 & 2 below ) other than t he designed on e. This vent w as

connected back in the govern ing rack header.

FRF AN D LUB OIL M IX UP

Fig -1

Shri. S. M andal



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Fig -2

The extra dra in w as cut at bo th ends and du m m ied. Thus a great t roub le of m ix up of lub o i l wi t h FRF w as

avoided


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OBSERVATION:

Dur ing checking of HPT and IPT casing top and bot tom temperature thermocouple, fo l lowing

observat ions w ere m ade.

HPT top th erm ocouple depth (L & R ) - 100 m mHPT bot t om t herm ocouple depth ( L & R ) 100m m

IPT top th erm ocouple inser t ion d epth (D) , ( L & R ) - 20 m m / 20 m m

IPT bot t om t herm ocouple inser t ion dept h( D) , (L & R ) - 35 mm / 35m m

ACTION :

As per th e drawing (0-10601-18000), the depth o f IPT top and bot t om therm ocouple depth f ro m casing

sur face is to be sam e. As per t he above data, the d epth f rom the o uter sur face of t he casing to t he bot tom

of the ho le was 35 mm in case o f the bo t tom tem peratu re therm ocoup le and the same fo r top t empera tu re

one was 20 mm. Since there was var ia t ion observed in the measured values of IPT top bot tomtherm ocouple dept h, the m atter w as referred to BHEL/ Hardwar. As advised by Hardw ar, the t op s ide hole

depth w as increased by 15 mm to m ake i t equa l to tha t o f the bo t tom ones.

IP CASING TOP BOTTOM DIFFERENTIAL TEM PERATURE

Four t hermo coup les( two a t t op & tw o a t bo t t om)

Shri. S. M andal



28/40



29/40


OBSERVATION:

During f irst synchron ization of Paras-II, th e gland steam leak off l ine t o GSC and GSC vapour l ines wer e

not ful ly ready (ref f ig-1). So as a alternat ive, system l ineup w as m ade as per t he enclosed valve posit io n.

Vacuum w as pul led and dum ping act iv i ty star ted. Af ter comp let ion of dum ping, before star t o f ro l l ing, itw as not iced th at th ere was no steam com ing out of t he leak of f l ine exhaust .

ACTION:

The g land steam supply va lve to t he GSC (M AW80AA001) w as opened and lo t o f w ater gushed ou t

f rom the U- loop d ra in .

The p ip ing w as la id as per th e scheme ( 2-13100-29121) and in the scheme, the U- loop dra in w as

envisaged after th e isolat in g valve(M AW8 0AA001). This layout defeats the drainin g of cond ensation un der

the above m ent ioned l ine up. The m atter w as referred to BHEL/ Hardwar for changing the U- loop posi t ion

from dow nstream of iso lat ing valve to upstream po si t ion. Such layout w as a l ready envisaged in 500M W set( as enclosed) . Wit h t he concurrence of Hardw ar, the U- loop po si t ion w as changed.

W ATER ACCUM ULATION IN THE GLAND STEAM LEAK O FF LINE TO GSCShri. S. M andal


Scheme as was given in th e draw ing


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M r. S. M andal graduated in M echanical Engineerin g from Jadavpur Un iversity,

Kolkata in 19 84.

M r. M andal join ed BHEL in 1984 as engineer t rainee and w as posted in TSX dept.He has 24 years of r ich experience in Steam and Gas Turb ine com m issionin g.

At pr esent he is wo rking as Addit ional General M anager in TSX dept at Paras site.

v v v


31/40


DESCRIPTION:

The EBFP is pro vided in CFBC boiler for t he pu rpo se of m aintaining t he dr um level in case of em ergency

dur ing boi ler operat ion. The pum p provided is dr iven by a d iesel engine, wh ich can be run thro ugh a

remote com mand f rom the con t ro l room. The ma in purpose o f t he pum p is to avo id sta rvat ion o f water in

the boi ler t ubes in case of an em ergency i .e . b lackout condi t ion.

START PERM ISSIVES: The pum p d oes not have any star t perm issive.

START CON DITION S:0

1. Com bustor low er tem p. greater than 450 C AND al l BFP's o f f for m ore than 5 seconds.0

2. Com bustor lower tem p. g rea te r than 450 C AND b lack ou t cond i t ion w i th no de lay.0

3. Bo ile r Pro tect ion-1 ac ted and com bustor low er temp. g reate r than 450 C and al l BFP's o f f fo r mo re

than 5 seconds OR Black out condi t ion w i th no delay.

The EBFP has no d i rect t r ipp ing com m and f rom contro l room al l the t r ipp ing to th is pum p are f rom localpanel of th is pum p. The condi t ions in w hich the pum p w i l l t r ip are as below : -

1 . Lube o i l header p ressure very LOW.

2. Deaerato r leve l very LOW.

3. Engine local panel t r ipp ing incorporated for engine safety.0 0

4. Bear ing temp erature very HIGH (Gearbox bear ings at 110 C, Pum p bear ings at 90 C) not in serv ice

due to custom er requ i rement .

CHRONOLOGICAL ORDER OF EVENTS ON 0 2/ 06 / 201 0 UN IT #4 SLPP M AN GROL:

1 4:5 8 U nit #4 t r ip ped on dr um level ver y h igh .

15 :21 BFP- A t r i pped on suct i on p ressu r e low , t he deae ra to r l evel obse r ved at t h i s t im e was

(-) 1230 m m Wc.

15 :22 EBFP got sta r t com m and f r om con t r o l r oom . EBFP sta r t ed (Fig. 1 ).

15:33 EBFP t r ipped.

15 :40 Engine was t r i ed t o s tar t f r om loca l panel . Since deae rato r l eve l, lube o il p r essu r e and

bear ing temperature were normal , i t resul ted in burn ing of one of the terminals of the

bat tery bank.

1 7: 45 Pu m p an d en gi ne w e r e d eco u p le d a nd fo u n d t h at p u m p w as se ize d.

OBSERVATIONS:

1. The EBFP w as run on aut o m ode as soon as the ru nning BFP in the uni t t r ipp ed.

2 . There was no f low observed in the feed con t ro l sta t ion o f the bo i le r.

3 . The mechan ica l seal o f the pum p has go t damaged.

REPORT ON EBFP FAILUREShr i. Preet ham V.

Engin eer (TSX), M angro l Site


32/40


4. The pum p discharge pressure was decreasing gradual ly, when t he pum p w as running in min im um

re-circulat ion.2

5. The suc t ion p ressure o f the pum p decreased to 0 .46 kg /cm w hen the deaera to r level was ( -)

758m m Wc (Fig. 2 in increasing t rend) w hereas the t r ipp ing of t he pum p is at ( - ) 1600mm Wc.

6 . There may be som e vapour fo rm at ion in the deaerato r as pegging o f deaerato r w as cu t o f f and

w ater tem p and pressure in the d eaerator w as gradual ly com ing dow n.

7 . M ay be the ba lance leak o f f does no t p rov ide any ci rcu lat ion w hen the pum p is no t in serv ice, wh ich

m ay lead to u neven expansion in t he pum p im pel ler and casing.

8 . The suc t ion st ra iner o f the pum p was c leaned on 31 /05 / 2010 and pum p w as run fo r 5 m ins on

01/ 06/ 2010. Later on inspect ion of suct ion st ra iner, i t w as found c lean and had n o dam age.

ACTION SUGGESTED:

1. The pump shou ld be t r ipped on low suct ion p ressure also .

2 . The pum p m ay be p rov ided w i t h a w a rm up l ine f r om the f eed wa ter l i ne , wh i ch wou ld keep t he

pum p ready for ru nning any t im e. In exist ing uni t s (1& 2) , the EBFP's have warm up l ine w i th am oto r ised iso lat ion valve.

Fig. 1


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Fig. 2

M r. Preetham com pleted h is B.E. in M echanical from Natio nal Inst i t ut e of Technolo gyKarnataka, Surathkal in M ay 2005. He comp leted a pro ject o n Low tem perature

Rankine Cycle in 20 05. M r. Preeth am Joined BHEL on 13t h ju ly 2005. Since 2006, he is

w orkin g as a Boiler Com m issionin g Engineer. Wor ked in Dabhol p roject in 20 06, later in

M PPGCL Birsinghpu r 500M W ti l l 2009 and p resently w orkin g in SLPP M angrol

2x125M W CFBC.

v v v


34/40

INTRODUCTION:

l

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l

l

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NTPC KSTPS 200 M W KW U design Unit-1 TG set w as com m issioned o n 28/ 02/ 1983. The m achine had

comp leted around 1,95,925 running hours t i l l th is shut do w n. Uni t w as w i thdraw n on 02/04/ 10 due to LP

inner - inner com pensator bel low fai lure. The m ajor act ivity of LPT rot or replacem ent and LP casing

compensator replacement were carr ied out during this overhauling. This art icle covers observations,

act ion taken and sequent ia l procedure for LP casing inner- inner to inner out er com pensator bel lows

replacement .

OBSERVATIONS DURING LOAD :

Heavy abnorm al sound w as observed f rom LP Turbine d ur ing m achine w as on f u l l load.0

IPT exhaust steam tem perature observed as 290 C.IPT exhaust steam pressure observed as 5.0 Kg/cm

0LPH2 out le t tem perature observed as 80 C.

The heavy sound o n LP Turb ine and low pressure in IP exhaust l ine clearly indicates the bellow fai lure

in LP inner - inner com pensator. The Failure w as occurred in th e m ont h of Decemb er 2009 and BHEL advised

NTPC to replace the com pensator imm ediate ly to avoid m ajor dam ages. Due to non avai lab i l ity of spares at

si te , NTPC run t he m achine w i th bel low fa i lure condi t ion for fou r m ont hs.

OBSERVATIONS AFTER DISM AN TLING OF LP TURBIN E:

The fo l lowing o bservat ions were m ade af ter d ism ant l ing of LP Turb ine.t h t hDeep dent / bend and cu t marks was observed on the lead ing edge o f a ll the b lades o f 6 & 7 stages

of M oving & Guide b lades at bot h Turb ine & Generator s idest h

Last stage (8 ) b lades leading edge around 100-150 m m in length at bot h s ides found heavy erosion

m arks and l ight dent m arks.

FEED BACK ON LP TURBINE INNER-IN NER COM PENSATOR BELLOW S FAILURE

AT KSTPS UN IT-1, 20 0 M W TG SET NTPC KORBA

V.Veerapandi

Sr.M anager/ Ser BHEL-PSW R Nagpu r

E-mail :vpan di@ bhelp sw r.co.in

Dent and bend m arks on M oving & Guide b lades



35/40

COM PENSATOR BELLOW S AND THEIR SUPPORTS

LP inner- inner to inner outer compen sator bel lows at r ight side found m issing and the broken bellow

pieces are passed thro ugh extract io n l ine.

Broken p ieces of inner- inner to inner ou ter comp ensator bel low w ere found in betw een inner- inner

and inner out er casing and LP Heater No.2 inlet l ine.

COM PENSATOR BELLOW FAILURE AN ALYSIS

LP inner- inner casing bot t om hal f w as rem oved af ter cut t ing of bo th side in let p ipes. In let s team pipes

and t heir suppor t s were th oroughly inspected. Dur ing inspect ion o f r ight s ide inner comp ensator, a long

crack w as observed f rom t he longitud inal w eld jo int o f bel low protect ion p ipe. The in let steam f low w as

direct ly h i t on the com pensator bel low through the cracked por t ion of protect ion p ipe and i t lead to

fa i lure of bel low.

ACTIONS TAKEN:

Damaged LP Roto r w as replaced by new rotor .

M PI & NFT of last stage free stand ing blades.

LP inner- inner to inner out er comp ensator bel lows (Dn 800) on le f t & r ight sides (2 Nos) w ere

replaced.

LPH3 ( A3) bel low ( 1 No.) w as replaced.

COM PENSATOR BELLOW REPLACEM ENT PROCEDURE :

1. Remova l o f ou te r p ro tect ion cover o f ou te r com pensator bel low be tw een Gi rder & inner ou te r casing

on bot h side.

2 . Cut t ing /Gr ind ing o f ou te r p ro tect ion cover suppor t r ing on bo th sides.

3 . Cut t ing / Gr ind ing o f f lange we ld jo in t w i th the inner -inner compensator on bo th s ides.



36/40

4. Cut t ing and push ing the inner p ro tec t ion p ipe o f ou te r com pensators tow ards G irder side o f the steam

inlet p ipes at both end to faci l i tate the out er com pensator rem oval .

5 . Cut t ing and tak ing ou t o f ou te r com pensator (Dn 800) be l low (be tw een Gi rder & inner ou te r casing )

on b oth sides.

6 . Cut t ing o f l ip jo in t be tw een inner -inner casing and th e inner -compensator on bo t h s ides.

7 . Push ing the inner -inner com pensator (Dn 800) towards ou te r com pensator be llow end on bo th s ideto faci l i tate l i f t ing of inner- inner bot tom casing.

8. Recording the axia l & radia l posi t ion of inner- inner casing.

9 . Record ing o f e levat ion read ings o f the inner - inner casing at t he four pa lm.

10. Rem oval of eccentr ic bushes & axial keys of th e inner- inner casing.

11. Cut t ing of A3 (LPH3) com pensator (Dn 400) jo in t betw een inner- inner casing & inner out er casing

connected to A3 Extract ion p ipe l ine below the inn er-outer casing

12. Rem oval of bot tom hal f o f inner- inner casing.

13. Placement of bot h side inner- inner comp ensator bel low into t he outer casing steam in let p ipes af teredge preparat ion at bo th sides.

14. Placement of inner- inner casing bot t om hal f in posi t ion. Assem bly of eccentr ic bushes & axia l keys and

align the in ner casing by radial / axial direct ion w.r. t or iginal reference.

15. Al ignm ent and preparat ion of t he l ip jo in ts on both s ides.

16. Placement of T/ H of inner- inner casing & inner outer casing and t ightening of th e al ternate bol ts af ter

prop erly locking the in ner- inn er casing w.r. t inner -out er casing. (This is to b e don e to el im inate any

distor t ion dur ing th e w eld ing of p ipes) .

17 . Placement o f inner p ro tec t ion p ipe (new one) o f o u te r compensator be l low and push ing towards

girder end to fac i li ta te f ina l p lacement o f out er com pensator .

18. Placem ent of ou ter comp ensator in posit ion at bot h sides, a l ign the outer com pensator w i th inner-

inner compensator & steam in let p ipe at bot h sides w i th prop er w eld ing gap.

19 . Weld ing o f inner com pensator at bo t h sides a t a t ime w i th tw o w e lder.

20 . Weld ing o f ou te r com pensator a t bo th sides a t a t ime w i th tw o w e lder.

21 . A l ignment and we ld ing o f inner p ro tect ion p ipe o f ou te r compensator.

22. Preparat ion and w eld ing of the jo ints of the inner com pensators w i th the f langes in the steam in let

pipes of out er casing on bo th sides.

23. Fi t t ing ,al ignm ent and w eld ing of suppo r t r ing of out er protect ion cover on bot h sides.

24. Assem bly of outer prot ect ion covers of out er com pensator bel low.

25. Taking out top halves of inner-outer and inn er- inner casings af ter comp let ion of w eld ing.

26. Al l but t jo in t ro ot w eld ing by TIG (TGS1CM ) and Arc weld ing by E7018. Radiography to b e conducted in

a l l but t jo in t and 100% DPT for a l l o ther jo in t s.



37/40

LP INNER IN NER & IN NER-OUTER COM PENSATOR A RRAN GEM ENT (RIGHT SIDE)

Protection cover Support r ing

LP I nner -out er casing Out er protection cover

I nner protect ion pipe I nner protect io n pipe

LP I nner- Inner casing STEAM FLOW

I nner- inner compensator

Outer compensator

Erection Joint

Lip Joint Er ect ion j oint

Flange connected to outer casing

A3 compensator



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Inner inner Bel low Fi t up Roto r p lacement

PARA M ETERS AFTER RECTIFICATION :0

1. IPT exhaust steam tempera tu re - 316 C.2

2. IPT exhaust steam pressure - 7 .0 Kg / Cm .0

3 . LPH 2 o u t le t t e m p er at u r e - 8 5 C.

CONCLUSION:

The replacem ent of inner comp ensator bel lows at bot h side and LPH3 (A3) compen sator bel lows by

l i f t ing of inn er casing bot t om hal f, LP turb ine o verhaul ing w ork a long w i th LP rotor replacem ent inc ludinghoning / reaming of IP/ LP & LP/ Generator coupl ing were carr ied out w i th in t he contract schedule per iod of

20 days. BHEL-PSW R SAS has adopt ed inn ovative t echniqu es, strat egies to m eet t he scheduled d eadlines.

v v v

Inner- inner comp ensator p lacement Inner- inner Bot tom hal f p lacement


M r. V. Veerapand i graduated in Production Engineering from Regional Engineering

College at Tr ichy in t he year 198 8.

M r. Veerapandi jo ined BHEL Trichy in t he year of 1988 and w as tran sferred t o PSW R-

SAS Services in 1991. Since t hen he is responsible fo r Overh auling, Troub le shoot ingand Servicing wo rks of Steam Turb ines of various ranges up t o 500M W .


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Dear Frien ds,

S N M ai t i

General M anager (TSX),

BHEL, PSW R (HQ),

Nagpur.

This is a special issue on latest techn iques to be ado pt ed for b oi ler w ater t reatm ent . As

you are aw are, wi th in nex t tw o t o t hree years a l l our com m ission ing engineers shal l behandl ing super c r i t i ca l un i ts where a l l drum t ype steam generators shal l be rep laced

w i th on ce thru bo i lers. Quali ty o f feed w ater requi rem ent for a l l once thru b o i lers shal l

be m ost s t r ingent & requ i re a to t a l ly d i f ferent appro ach for on l ine t reatm ent .

Al l volat i le t reat m ent (AVT) wh ich is a mu st for al l once th ru bo i lers shal l not be able to t ake care of residual

hardness present in feed water since boi ler water pH w i l l be m ainta ined by Am m onia so lu t ions instead of

convent ional coord inated phosphate t reatment . Hence for tak ing care of a l l res idual hardness,

comm ission ing of cond ensate p o l i sh ing un i t i s must r ight f rom in i t ia l stages for safe & re l iab le operat ion of

the p l an t .

Apart f rom AVT t reatm ent , there is a to ta l l y new concept o f Oxygenated t reatm ent(AVTO) o f feed water

cyc le w here O2 is in jected in to the feed cycle for t ransform at ion of scale f rom m agnet i te to hem at i te &

prot ec t ive hem at i te layer thus form ed reduces the ra te of scale form at ions by a lm ost 50%. I t is a lso

c la imed that Oxygenated t reatment reduces the f requency of pos t operat ion chemical c leaning

considerably. Is not i t t hr i l l ing? All along, w e have concen trated on rem oval of oxygen from feed cycle to

m in imize corrosion. Hence w e a ll mu st t ry to u nders tand the chem ist ry o f oxygenated t reatm ent .

This new techn ique of b oi ler w ater t reatm ent is envisaged in NSPCL Bhi lai dru m typ e boi lers. Therefore

unders tanding of t he ent i re operat ion p h i losophy & a l l sor t s o f pos t operat ional feed b acks shal l be very

m uch usefu l to a l l o f you.

Overal l we are in receipt o f lo t o f feed backs f rom a l l our s ite engineers in d i f ferent areas of o perat ions . Due

to space constraint al l feed backs / w ri te u ps are no t included in th is issue. How ever, we assure you t hat al l

valuable feed backs shal l be pu bl ished in th e next issue o f Taknik i Darpan.

I w ould o nce again em phasize th at t he fu ture of BHEL lies on quick adopt ion of lates t technolog ies &

explor ing the a l ternat ives by ou t o f box t h ink ing w i th respect to t im e cycle reduct ion in a l l our processes.

This is possible by imp roving Core Com pet encies o f each & every ind iv idual in all f ie lds of op erat ion .

W i th bes t w ishes to a l l o f you,

TECHNICAL SERVICES, BHEL-PSWR 37

AND THE LAST PAGE


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BHARAT HEAVY ELECTRICALS LIM ITED

POW ER SECTOR W ESTERN REGIO N

Shree M ohini Com plex, 345, Kingsw ay, Nagpur-44000 1.in

ted

atAQUA

PROCESSPh.

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takniki darpan - issue 6[1]

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