ALKALI FLUSHINGOBJECTIVE

To remove dust, rust, grease, slag of weld aments etc otherwise this presence will contaminate the system

ALKALI FLUSHINGLine capacity of regenerative system including DEA - 300 T

Employed only for condensate & feed system piping only ( excluding Heaters )

Commissioning of regenerative system includes

Main condensate system Eqpts: CEP, EJECTORS, GSC, DRAIN COOLERS, LPHs, DEALines: CEP R/C line,LP B/P spray line, Excess condensate to surge tank,Condensate lines and its B/P lines

Feed system

Equipments: BFPs ,HPHs

Lines : Suction line,warm-up line, R/C lines, feed discharge lines, GPV U loop, HPHs B/P lines

Drain condensate system

Heaters to next heaters drain condensate line

Heaters to FB line

Condensate & Feed lines alkaline flushing will be carried out

For other lines only hydro test will be carried out after erection work is over to check the weld joint Before erection individual pipe is cleaned and hydraulically tested

PRE COMMISSIONING CHECKS Standard check lists to be prepared for all items listed in the inventory ( i.e ) heatersand motor foundations ,pumps,deaerator,heaters, filters, valves, cabling, orifice plates, instruments,platforms etc.

Where temporary items have been welded to the parent metal ,surfaces must be made good and area must be checked by means of crackdetection techniques

Internals of deaerator ,Hp , Lp heaters must be inspected and cleaned by wire brush orhand

Nozzles in the dea tray will be removed andput back after flushing

Deaerator is the largest vessel in the LP feedsystem and final inspection includes check for removal of temporary stiffness and also that wedges, clamps etc are removed

After the erection of dea , a hydraulic test willbe carried out as part of the erection activityto check feed storage tank leak due to welding works

Hydro test of pipes which was welded at site and check for passing of valves

REQUIREMENTSTrisodium phosphate - 2000 kg (approx) ( Na3Po4 ) Sodium hydroxide - 1200 kg ( NaoH ) Lissopal D 300 - 200 kg ( Teepol )

Filtered water - 2500 t ( app)DM water - 2000 t Thermometer - 0 200 oC( 2 Nos)Sampling bottle - 12 Nos

Lab Equipments - To test alkalinity, ph , conductivity, temporary piping , flanged dummies as per site conditions

Alkali flushing pump 200 t/hr- 2 Nos ( OR )

- 150 t/hr- 3 Nos

Delivery Head - 120 MWC

Mixing tank capacity - 50 T 1 No

TRISODIUM PHOSPHATEHard scale forming substances will be converted into soft sludge

SODIUM HYDROXIDEStrong base To maintain ph If it falls to acidic iron materials will be eaten away

LISSOPAL D 300

Acts as a wetting agent

Loosen the debris

PRECAUTIONSAll NRVs ,Orifices to be removed

Necessary lines to be dummied & looped

BFPs &Booster pumps will be bypassed

Heaters will be bypassed

PROCEDUREMASS FLUSHING - Cold water - Hot water

ALKALINE FLUSHING

RINSING - First rinsing (once through ) - Second rinsing - Final flushing with DM water ( HOT )

BASIC TECHNIQUES To create a fluid velocity greater than when the system is in service

To disturb debris and carry the particles along its flow so that it can be trapped or discharged from the system

TO ACHIEVE HIGHER VELOCITIES

By employing high pr & flow pumps ( Normally 300 to 400 t/hr flow is to be established for effective flushing )

Sectionalizing the system so that higher velocities are created by less number of flow paths

Reducing the system resistance by removal of components which restricts flow such asorifice plates, filter internals ,NRVs & valves

Heating the flushing medium

Using a medium less viscous than the working fluid

To disturb debrisHammering the pipe To dislodge internal scale and disturb debris

Thermal cycling Used primarily to remove scale and other flaky particles from internal surfaces

Sudden changes in the velocity of flushing medium

By creating turbulence By introducing air into the flushing medium

PRECAUTIONSAt any stage all pumps should not be in stopped condition when alkaline flushing is taking place

If one pump trips start the other pump

COLD WATER FLUSHINGScheme is made ready in such a way that initially all equipments in the condensate system were excluded for flushing

After flushing the lines equipments included one by one for 20 minutes

All flushed water will be drained to atmosphere

FLOW PATHWhen R/C line closed

Alkaline tank- spray LP B/P valve- CEP dis.header- Ejector- GSC- HW control station- DC- LPH 1,2,3- Dea B/P valve- return header

When LP B/P injection closed

Alkaline tank- R/C line- HW control station- DC- LPH 1,2,3- Dea B/P valve- return header

Shortest route to Dea

From tank R/C line- HW control station Excess condensate to surge tank- Surge tank to dea ( through temporary B/P line )

During flushing check

Ammeter reading & dis pr

Amps & dis pr will be more if there is line choke

PROCEDUREStart the pump

Flow circuit pump discharge-CEP R/C-LPHs B/P- DEA B/P return header- drained to atmosphere (LP B/P spray valve closed) duration 45min to 1hr

Pump discharge - LP B/P spray valve 1&2-Ejector B/P GSC-LPH B/P DEA B/P- return header-drain 15 min R/C line closed

Ejector A included- B/P of ME closed (15 -30 min )Ejector B included- Ejector A I/L closed (15 -30 min )GSC includedLP B/P spray valve 3&4 included & 1&2 isolated

Drain cooler & LPH 1 taken (45 min)

LPH 2 taken for flushing (30 min )

LPH 3 taken for flushing (30 min )

Dea B/P closed Dea filling started ( through shortest route )

Dea filled completely & feed system charged

BFP A,B,C suction line flushed ( BFPs &BP will be bypassed )

CEP Excess condensate to surge tank flushed

All BFPs R/C line & warm-up lines flushed (warm up lines dummied at flash box and looped together near FB box)

GPV U loop flushed

HPH 5&6 B/P flushed

HPH 5&6 flushed on tube side

Cold water flushing completed

Stop the pump

HOT WATER FLUSHING (DM WATER)Start the pump

Charge the system & kept under circulation

Admit steam in the tank

When the return header temperature reaches around 80 oC flushing activity started by including the equipments one by one and by closing its bypass valves and samples were taken for every one hour

Hot water flushing is said to be completed when conductivity at both I/L & O/L are same

SAMPLE RESULTSTime Temp Conductivity in s/cm I/L O/L I/L O/L14:00 87 78 7.9 815:00 85 80 11.8 13.1.. .. .. .. .... .. .. .. ..21:00 87 80 14.8 15.5

High conductivity means ions because of more impurities

After flushing stop the pumps and open all the drains

Alkaline flushingHeaters ( tube side ) will not be flushed

Only lines will be flushed during alkaline flushing

8:00 Fill the tank with filtered water and raise it ,s temp to 50 oC by admitting steam Start the pump

Fill the system completely and kept under circulation for 15-20 minutes Add chemical reagents slowly

10:00 Add Na3Po4 10 bags Caustic soda flakes - 5 bags11:00 Add Na3Po4 20 bags Caustic soda flakes - 10 bags12:00 Add Na3Po4 20 bags Caustic soda flakes - 10 bags Teepol B 300 - ( 3 can )

Na3Po4 35 bags - 35*50 kg

Caustic soda flakes 20bags - 20*50 kg

Teepol B 300 - ( 3 can ) - 0.2 kg / ton of water

Mix the chemicals thoroughlyRaise the temp to 80 0C & maintain it throughout the processCirculate the solution through the system for 10 hrsCheck the concentration

Add more chemicals to the solution if necessaryIf more dust is there then more chemicals are neededSamples to be taken at I/L &O/L for one hourAnalyse ph & iron content Process is said to be complete when values are same at I/L &O/L

CIRCUIT14:00 Alkali flushing started . 4 nos LP B/P spray valves opened & CEP R/C closed14:40 CEP R/C opened and one pair of LP spray valve closed15:15 Other pair of LP B/P spray valve taken15:15/ CEP excess condensate to surge tank 15:30 taken

15:30 to All LP B/P spray valves &CEP R/C 15:40 valves15:30 to BFP A suction line 15:45

15:45 to BFP B suction line 16:1516:15 to BFP C suction line 16:45

16:45 to All R/C line & warm up line17:0017:00 to GPV U loop 17:3017:30 to HPH 5&6 B/P line 18:00

Entire system kept under recirculationTime Alk ph PO4 Alk ph PO4 I/L O/L14:00 4240 12.37 3040 4160 12.35 300015:00 4320 12.5 3200 4240 12.5 3120 .. .. .. .. .. .. .. .. .. .. .. .. .. ..21:00 4000 12.42 3120 4000 12.42 3120

21:30 Steam valve closed

21:45 Alkali flushing completed . Drain valve near neutralising pit opened and draining started to pit

FIRST RINSING (ONCE THROUGH )Mixing tank was filled with water and drained to trench three times to clear off the alkalinity from the tankMain condensate gate valve to dea was closed. Temporary B/P valve was opened.Dea drain was closed

00:00 Pumps started and once through to flushing through LP B/P spray valves, 3:00 CEP R/C line , all equipments B/P line to pit to wash out the alkalinity3:15 Dea was filled partly and drained to clear off alkanity. Dea filling started after closing its drain valve

After filling the dea charge the feed system . Water returned to the flushing tank will be diverted to neutralising pitPumps stopped Tank was drained to the trench

SECOND RINSING13:30 Mixing tank was filled with water To Start the pump & charge the system17:30 Condensate system was flushed and diverted to neutralising pit 17:45 Close the drain to neutralising pit Open the return drain to tank and kept under recirculation

Rinse BFP suc.lines ,warm-up line, r/c lineone by oneRinse GPV U loop , HPH 5&6 B/P line oneby oneSystem will be under recirculationTake the sample at I/L & O/L

Time Alk ph PO4 cond Alk ph PO4 cond I/L O/L18:30 16 10.09 10.4 58.2 15.2 10.05 10 55

20:15 14 10 10.4 49.8 13.8 9.96 10.2 48.2

21.30 Second rinsing completed

Pumps stoppedDraining startedAll lower most point drains near heaters, warm-up line drain , suction filter drain opened

MASS FLUSHINGMixing tank was filled with waterStart the pump1:00 Charge the condensate system andto kept under Recirculation ( by passing 4:00 all heaters ).Feed system was charged and kept under recirculation ( by passing HP heaters ).

4:00 rinsing of ejectors ,GSC, LPHs ,HPHs to carried out though their coils , closing the6:00 bypass one by one, making all the flow through the equipments .

Purpose : To clean any left out alkaline solutions inside the tubes due to passing of valves

5:30 First sample was taken and taken for every one hour10:30 Steam was admitted in the tank12:45 Temp reached to 80 0C. Samples collected & analyzed.When the results were satisfactory ,clear up mass flushing

Time Alk ph PO4 cond Alk ph PO4 cond I/L O/L5:30 12 8.8 10 15.3 12 9 10 19.3

6:30 11.2 9.07 10 14.9 11.2 9.07 10 18.8

7:30 10.4 9.05 10 29.2 10.4 9.06 10 31.6

Time Alk ph PO4 cond Alk ph PO4 cond I/L O/L10:30 10.8 9.45 12 30.5 10.8 9.45 12 25.7

12.30 10.4 9.1 12 39.5 10.4 9.1 12 26.4

15:00 Pumps were stopped after cutting out steam15:10 Draining started .All drains were opened. Dea vent was opened.

SAFETY PRECAUTIONSAlkali solution may cause skin burning.

It,s fumes to eyes are injurious. Henceoperators must use gloves, eyes protecting glasses ,masks, gum boots etc.

While tightening the flanges of temporaryjoints care must be taken so that they do not leak when the pump is in service

Ensure the availability of first aid kit, cottonroll , eye drops etc.

HPH FLUSHING HPH5 DEAFBCharge the system through shell drainHPH6 Dip to dea-Dea to HPH5- HPH5 to FB-AtmosphereHPH6 to HPH5-HPH5 to FB- AtmosphereHPH 6 to FB- AtmosphereTemporary lineHPH 6

Hydro test the pipes which are welded ( DrainCondensate lines )

Cold flushingStart the pump- charge the system( shell side)Though shell drain

CircuitHPH 6 Drip to dea Dea to HPH 5- HPH 5 To FB - AtmHPH 6 to HPH 5 HPH 5 to FB AtmHPH 6 to FB - Atm

HOT WATER FLUSHINGStart the pump charge the system kept in Recirculation- Admit steam Take sample When return water temp reaches 75 0C.Flushing is said to be complete when Conductivity at both I/L &O/L same.

LP HEATER FLUSHINGLPH3LPH2LPH1

FBDCFBTemporary lineRETURN HEADER TEMPORARY

OBJECTIVECheck the internals and free from waste,debris and clean the internalsHydro test the lines which are welded

COLD FLUSHINGPump stated .LP heater shell side charged through shell drainCircuit - LPH3 - LPH 3 to FB to LPH 2 LPH 2- LPH 1 LPH 1 to DC DC to FB FB to atm

LPH 3 to LPH 2 LPH 2 to LPH 1

LPH 1 to DC DC to FB - atm

HOT WATER FLUSHINGStart the pump charge the system kept in Recirculation- Admit steam Take sample When return water temp reaches 75 0C to 800CFlushing is said to be complete when Conductivity at both I/L &O/L same.Flow circuit will be same as cold water flushing

LOGICS CHECKING

MOV Checking

Air valves air line blow out & checking

Flushing of level transmitters & lines

Logic checking of switches

HYDRO TEST OF BFP SUCTION LINE

TEST PR 19.2 K.SC DURATION- 30 mts PR AFTER TEST - 18.7 k.sc DROP IN PR 0.5 k.scDEABPBFPDDPI0 60 KSC

AST TO SEALS HYDRO TEST

AST HEADERPITO TURBINE GLAND SEALINGNRV FLAPREMOVEDEX 15 CLOSEDAS 10NRV FLAPREMOVEDCONNECTION FOR PRESSURISING PUMPMAW 100-60 kscMAW 10 bef gate valve closedAS 10 openTest Pr - 50 kscTime 30 mts

STEAM BLOW OUT OF CRH TO DEACRH to Dea was warmed up slowly by opening main valve few turns Keep the drain and air vents opened for a few minutes

CRH TO DEA SCHEMEMOVB/PB/PTO DEAPCVFROM CRH LINE

CRH TO DEA MAIN LINEBlow out was carried out for 15 minutes at a Pr of 14 ksc &temp 320 oCCondition before blow outBef & after pr control valve was in closed ConditionBoth B/P valve of pr control valve was in closed Condition

CONDITION DURING BLOW OUTBef valve of pr control valve and its B/P in Open conditionAll drains & vents in close condition

CRH TO DEA B/P LINECondition before blow outBef iso valve ( MOV ) of pr control valve was in close condition

CONDITION DURING BLOW OUTAfter isolating valve of pr control valve wasOpenedB/P valve ( western side ) of pr control valve was openedB/P valve ( eastern side ) of pr control valve was opened

COMMISSIONING OF BFPLUB OIL CICUITA temporary heating source and centrifuge is desirableCentrifuge to remove dirts & heat the oilNRV S & Orifices to be removedInspection filters will be provided at the return oilline

Brgs will be removed and lub oil line will besuitably bypassedGeneral condition of the lub oil system shouldbe inspected and the system must be cleaned manually bef being charged with oil

ALOP s will be startedCollection at inspection filters will be seen periodicallyAfter oil flushing inspection filters will be removedBrgs will be placed in positionSupply to brgs made though

FUNCTIONAL CHECKSRequired conditionBreaker will be in test positionPumps charged conditionALOP runningAll switches & indicators made through

PERMISSIVESSuction valve open & dis valve closedLub oil pr adequate ( > 2 ksc )Working oil temp < 110 o CR/C valve openTop & bottom casing difference

PROTECTIONSWorking oil temp V.high > 130 oC Local latchSuction & discharge T > 10 oCLub oil pr low (1.2 ksc)Suction pr V.low ( main pump < 9 ksc )Dea level V.low ( 180 mm of wcl )Suction strainer P high ( 0.5 ksc )

ANNUNCIATIONSBrg temp highOil tank level lowLub oil temp O/L of oil cooler highWorking oil temp highStrainer P highSuction pr lowDea level low

Reserve startingReserve starting must be proven for both buses

OPERATION & PERFOMANCEEnsure lub oil supplyMotor in decoupled conditionCheck DORRun the motorCheck winding temp, Brg temp riseMovement of the shaft must be within limitsIf it is more it will touch thrust pads

Couple the motorEnsure cooling water for coolers, sealsScoop tube operation tube to be checkedAll valves checking ( R/C,MOV,Pneumatic )Fill the dea and charge the systemStart the pump with dis valve in closed Condition & R/C open & min scoop condition

Record starting & steady state currentCheck for vibrations ,oil flow through brgs, suction &dis pr ,leak off pr, oil pr to brgs,lub oil temp,working oil temp, brg temp flow at frequent intervalsSpeed will be measured through tacho meter

Speed may be increased slowly and readings may be takenAll personnel near the pump are protected from noiseAfter running of 8 hrs stop the pumpPump performance characteristics should bechecked against the supplier,s curve

DEA SAFETY VALVE FLOATINGRequired conditionsFill dea up to normal working levelEnsure AST is chargedPreheat water to 75 oC

ACTIVITIES TO BE CARRIED OUTClose R/C gate valves of all BFPs at dea levelClose BFP suction valves & isolate powerSupplyClose main condensate line valve at deaClose O/F valve DR 33 bef & after gate valveCRH to dea ext valve EX001 & it,s b/p valveClose DM 20 & it,s bef gate valve

Close operating vents of HPH 5&6 at dea levelClose HPH 5&6 drain condensate to dea iso.valvesIsolate dea level columnClose SM 20 & check its operation

PROCEDUREGag all line and dome safety valves exceptThe one to be floatedOpen gradually AST to dea B/P and slowlyraise dea prEnsure the opening of concerned safety valve atthe set pr other wise reduce dea pr and adjustthe spring tension

Again raise the dea pr and ensure blowing ofSafety valve at the set prOnce safety valve is lifted,close the peggingB/P valve and open immediately SM 20Repeat the same procedure one by one for theremaining safety valves