TURBINE DRIVEN BOILER FEED PUMP EREC. &COMMNG -ABC OF THERMAL POWER PLANT

As  stated in earlier posts there are three Boiler Feed Pumps (3x 50%) in a thermal power station of 500MW and above. 2x50% turbine driven BFP ( normally working when unit is running above certain load ) and other is 1x50 % MDBFP  which usually runs during start up .

We have already explained in last few blogs about erection and commissioning of MDBFP . For TDBFP pumps are same whether it is booster pump or main pump. Instead of MOTOR driven we have variable speed turbine with disconnecting coupling both sides . In this blog we will discuss only the turbine as pumps are similar.

 Technical data of Turbine

a.  Maximum output                                         7575  KW

b.  Design rating 

        (Economical rating)                                  5732 KW

c.  Speed                                                            5275 RPM

d.  Speed range                                                  1494-5750 RPM

e.  Initial Steam Pressure                                   6.33 ata.

f. Initial steam Temperature                              289.6 0 C.

g.  Exhaust pressure                                           0.1064 ata.

Oil System

a.  Lube oil pump                                              2 Nos

b.  Emergency Oil pump                                   1 No.

c.  Jacking Oil Pump                                         1 No.

d. Oil vapour extractor fans                              2 Nos

PROCESS  : ERECTION CHECK

Foundation checking of elevation ,plan that is different pocket holes and other measurable items as per given approved drawing . This the protocol for taking foundation from civil vendor for erection  purpose .(elevation within+5mm/-10mm). 

Check that depth and verticality of each pocket is OK. Checking to be done by water level /dumpy level/ total station.

Distance from fixed reference axis e.g. A-row, B-row Columns.  (1mm / metre,  5mm Max.)- Establishing centre line as given in the drawing by putting distances from fixed point . This can be done by measuring tapes or by total stations .

Marking of equivalent axes on foundation. Plumb Bob / total station.

Fitting of half couplings to all equipment after ensuring corresponding fits.  For taper coupling, ensure around 80% contact between shaft & coupling.

Blue matching the top surface of foundation frame with corresponding bottom surfaces of equipment with around 80% contact.

Positioning and alignment of all equipment on the foundation. Measure distance between coupling half faces of following equipments by Vernier / Micrometer / Tape

            Booster Pump and Gearbox

            Gearbox and Drive turbine

            Drive turbine and BFP.

Grouting of Foundation Bolts. Check that nut has full contact with foundation frame after tightening.

Leveling and alignment of equipment  by jack bolts (within 0.1 mm / M). Dumpy / Precision Spirit level) and different thickness packer plates.

Foundation frame grouting. Now a days grouting is done with ready mix concrete of 25kg bags main supplier is ACC, PAGEL ,FOXROC etc. This is a specialised job it is advisable to do concreting in presence of suppliers representative to avoid any complicacy afterwards. Please insist on test certificate and cube testing on one day and three day sample. This may delay the process however by passing any of the test may complicate the situation afterwards. Major checks of equipment are already told during my earlier blog. Please go through it.

Alignment (lateral and angular) between booster pump & gearbox, gearbox & Drive turbine shaft, Drive turbine shaft & BFP, Measure distances between coupling flanges. This is done without any pipe connection ( water line ,oil line and steam line ). This is pre final reading and after doing final connection final reading to be taken. However during course of erection this reading is checked to find the effect of connection. Dial Gauge/Micrometer.

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Continued  to part –ii ( TDBFP)

BOILER FEED PUMP ERECTION AND COMMISSIONING FINAL PART-ABC OF THERMAL POWER PLANT

TYPICAL INTERLOCK & PROTECTION REQUIRED FOR BFP COMMISSIONING

Ensure completion, installation and readiness of all instrumentation works, as per instrumentation

schedule, on BFP/ Booster pump/ Motor/ Hydraulic coupling/ de- aerator.                         

                                               

Calibration, setting and testing of primary instruments.                

                  

 Pressure gauges/ switches/ transmitters calibration and installation and wiring up to JB.                              

 Temp gauges/ switches/ transmitters calibration and installation up to JB.                           

                  

 Level gauges/ switches/ transmitters.                  

               

Limit switches.                 

Installation of JBs, cabling & termination in local and control room.                          

Readiness of control supply to Panels:                                                                  

Availability of LT & HT supplies   and readiness of electrical protection instruments.         

Readiness of mechanical system.                                                                                            

 Oil system                         

 De=aerator                       

Compressed air system.               ( Compressed air is required for pneumatic valve operation.     

Charging and testing of panels.                 

Commissioning of motorized  valves,  actuators & pneumatic re circulation valve.                              

Checking of Interlocks, protections & Alarms:                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    .                              

                (i)   Calibration of speed control device like scope tube /thyrister control etc                       

                (ii)  Oil pressure low                       

                (iii)  Suction valve open                                

                (iv)  De-aerator level low                             

                (v)   Feed pump suction/ discharge temperature high.                   

                (vi)  Balancing leak off pressure. high                     

                (vii)  Re circulation valve open                    

                viii)  Bearings vibrations high (wherever provided)                          

                ix)   Remote/ local tripping          

                TRIAL RUN OF HYDRAULIC COUPLING

               

               

Readiness of lubrication oil & working oil coolers and availability of cooling water.

Charge lubrication  oil and working oil coolers.

Checking of HC interlocks & protections

Ensure alignment of Hydraulic coupling with BFP motor.

Ensure proper  earthing of Hydraulic coupling.

Check oil level in hydraulic coupling sump.

Start AOP and monitor lubrication oil header pressure.

Start trial run of Hydraulic coupling.

Check regulating oil pressure and set, if required.

Monitor all parameters of hydraulic coupling; Gauges are available /mounted on the equipment

                   I.   Lubrication oil and Regulating oil pressure.

                   ii.   Motor current.

                   iii.  Hydraulic coupling bearings temperatures.

                   iv.  Lubrication oil temp at L. O. cooler inlet and outlet.

                   v.   Working oil temp at W.O. cooler inlet and outlet.

                   vi.  Motor winding temps.        

TRIAL RUN OF BFP

               

               

1      Ensure free rotation of BFP by hand before coupling.                                                                                                                               

2      Ensure completion of alignment:                                                                                                                              

                     I.    Motor & Booster pump

                     ii.    Motor & hydraulic coupling.

                     iii.   Hydraulic coupling & BFP

Special attention to be given on pipe line final connection.Pipes to be ensured as free body  through

hanger adjustment.  No tension on pipes is permitted otherwise alignment  will be disturbed.

3              Flushing of mechanical seal cooling water lines for BP as well as BFP & Mechanical seal water

cooler cooling water lines.

4              Optimisation of oil flow through bearings by using orifice plates

5              Running of AOP

6              Charging of all system:  

                (i)  Lubrication oil/ working oil coolers

                (ii)  Seal water coolers

                (iii) Suction valve opening 

                (iv)  Re circulation valve (Isolation  valve) opening

                (v)  Charging of C&I local panels

7              Fill de=aerator and maintain normal level.  

 8              Interlocks & protections checking.

9              Start BFP.

10           Monitor all parameters of BFP and motor;

                    I.    Current

                    ii.    BFP suction pressure.

                    iii.   BFP discharge pressure.

                    iv.   Balancing leak off pressure.

                    v.    De-aerator level.

                    vi.   BFP suction/ discharge Differential Temperature.

                    vii.   Lubrication oil/ working oil pressures and temps.

                    viii.  Booster pump/ BFP/ Motor/ Hydraulic Coupling bearings and drain oil temps. 

                    ix.   Cooling water temps.

                    x.    Seal water/ seal water coolers temps.

                    xi.    Motor winding temps.

                    xii.   Bearing vibrations.

BOILER FEED PUMP ERECTION AND COMMISSIONING PART-VI ABC OF THERMAL POWER PLANT

FINAL COMMISSIONING OF BOILER FEED PUMP ( mdbfp)

Till my last dispatch we have discussed erection and commissioning of Boiler Feed pump including oil flushing of lubrication oil lines ,acid cleaning of the same , hydraulic test of coolers and other integral pipelines. Now we will discuss about Boiler feed pump commissioning as a whole. BFP( MDBFP) is one of the first major equipment need to be commissioned before Boiler light up.

Commissioning includes checking of following activities completion as per drawing and quality plan.

1              Erection completion of feed water lines.

2              Instrumentation stub parts completion.

3              Completion of Alkali/ detergent flushing of feed water system, as well as condensate system and heaters drip system.

4              Cleaning and normalisation of deaerator and feed lines

5              Checking & setting of hangers and supports of feed water lines including BFP suction lines, recirculation lines.

6              Deaerator filling with DM water.

7              Final flushing of the suction lines of Booster Pump & BFP .

Readiness of cooling water system

1 Erection completion of cooling water lines of,                                                                                                                                                                                                                                                                                                                                                                                                    

BFP Motor

                Lubrication  oil coolers and working oil coolers

                Seal water coolers of BP & BFP

2              Commissioning  of the motorised actuators of motor cooling water valve..

3              Checking & setting of hangers & supports of CW lines of CW system and motor cooler.

4              Availability & readiness of cooling water/ system.

5              Flushing of all cooling water lines of CW system and motor cooler.

Completion of  ACW  system and heat exchangers ,Pumps, tanks  ,pipelines with instrumentation.

Electrical and C&I work completion  of Feed Pump , Feed station , control valves ,actuators etc.

1              Meggering of BFP motor

2              Availability of HT supply

3              Ensure proper earthing of BFP motor and instruments panel..

4              Completion of instrumentation (bearing oil press & temp) impulse piping and mounting of

press/ temp gauges, and winding, temp RTDs

5              Filling of Hydraulic coupling sump with fresh oil after oil flushing & cleaning of sump

6              Oil pressure optimization  at motor bearings.

7              Ensure de-coupling of motor with booster pump and hyd. Coupling.

8              Ensure free rotation of motor by hand.

9              Checking of BFP motor protections and CW valve interlock.

10           Charging of CW system and lubrication  oil cooler.

11           Bumping of motor and checking DOR

12           Trial run of BFP motor

13           Monitoring of motor parameters.

                   I.    Motor current and voltage.

                   ii.   Motor winding temperatures.

                   iii.  Bearing temperatures.

Continued to concluding part

BOILER FEED PUMP ERECTION AND COMMISSIONING PART-V ABC OF THERMAL POWER PLANT

Oil pipelines are reassembled after acid cleaning is over.

Oil tank and duplex filters are clean.

Oil tank is filled to the required level with recommended oil. Oil should be filled through filter

/centrifuge. Oils of different quality / make should never be mixed. Follow OEM

Recommendation.

Oil pipelines are disconnected from the bearings. The bearings are bypassed by temporarily

interconnecting the inlet and outlet lines of bearings using temporary loops.

Oil lines are properly supported and all temporary supports are cut and removed.

Temporary line filter of stainless steel mesh is provided in the return line before entry to the tank to

avoid entry of dirt into MOT of Hydraulic coupling.

Working oil lines to working oil coolers disconnected at hydraulic coupling end and temporary loops

made as shown in the flushing scheme.

Temporary connections, preferably of transparent hose which can withstand temperature as high as

80⁰ C, are made across the bearings.

Portable centrifuge / electrostatic filtration unit is connected to the MOT of the Hydraulic coupling.

Suction of the unit is connected to the drain of MOT of Hydraulic coupling through suitable hose and  the 

discharge is left inside the Hydraulic Coupling tank through inspection cover.

Required instruments such as pressure and temperature gauges are calibrated and mounted in the

system.

Temperature of 65-75⁰C to be reached during oil flushing through centrifuge heaters.

With MOT of Hydraulic tank already filled with recommended oil, AOP is bump started to check the

direction of rotation of the pump.

After ensuring correct direction of rotation the AOP is run continuously and the system is filled

gradually.

Oil level in the tank is watched till oil flow is established throughout the system. Oil is topped up, if

required.

The system is checked for oil leakages and the leakages, if any, are attended.

Temperature of oil is raised to 65-70 deg Celsius by using the heaters of centrifuge or by external

heaters.

After attaining the elevated oil temperature, heater is switched off and cooling water is admitted in

the cooler to suddenly bring down the oil temperature to get an effect of thermal shock. Oil pipelines

are also tapped with wooden hammers during the period of thermal shock.

Oil temperature is again raised and thermal shock is given. Thermal shocks are repeated till oil

flushing is declared complete as per completion criteria.

The working oil and lub oil circuits are flushed separately by making suitable temporary connections.

Flushing of lub oil circuit is done in sub stages by grouping lines of two to three bearings ( to be

decided at site ) by suitable isolation of lub oil supply lines to other bearings to have adequate

velocity in the pipelines for effective flushing .

The filters are cleaned whenever there is an increase in differential pressure across the filter beyond

0.5 kg/cm² over the normal value. 

Periodicity of oil sampling and filter inspection is mutually decided at site.

Oil flushing of oil lines bypassing the bearings is declared complete based on completion criteria.

Hydraulic test of the pipelines is carried out at a pressure 1.5 times the working pressure with the

help of an external pump or the AOP itself. There should be NO leakage.

Temporary bypass connections / blanks / dummies / are removed and the pipeline connections with

the bearings are normalized.

Flushing of lub oil circuit with bearings included in the flushing circuit is started.

Flushing through bearings is declared complete based on completion criteria.

The oil used for flushing is drained and kept in safe custody. This oil can be used for flushing in

other units if the oil quality is found suitable. While using this used oil for flushing in other units,

filling should be done through centrifuge.

All the bearings are inspected and cleaned.

Fresh oil is filled in the system. Oil pump is run, flow through each bearing adjusted and flow of

return oil through each bearing ensured.

COMPLETION CRITERIA The flushed components are considered clean when the DP across the filter stabilizes and does not rise more than 0.2 to 0.3 ksc over the normal value after eight hours of continuous flushing. Also there should be NO deposition of hard particles in oil filters. Mechanical impurities ( through 0.45 micron filter ) and moisture content in the sample collected from flushing oil should be each less than 100 ppm in three consecutive samples taken at intervals of four hours. Continued to last part BFP commissioning

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BOILER FEED PUMP ERECTION AND COMMISSIONING PART-IV ABC OF THERMAL POWER PLANT

Acid cleaning and oil flushing of LUBRICATION oil line of BFP

OBJECTIVE:-  To obtain clean lubrication oil and dirt free lubrication  oil tank at Hydraulic coupling.

The pipelines shall be disassembled from flange joints after initial layout and welding completion.

Each pipeline shall be acid cleaned by soaking method.

After neutralization and passivation of each pipeline, the pipelines shall be reassembled for oil

Flushing .

Oil flushing for working oil and lub. oil circuits shall be done separately. Necessary temporary

connections shall be done for this purpose. Necessary temporary connection can be done during

erection stage and after flushing temporary connection can be removed and can be used in other

units.

During oil flushing of lub. oil circuit bearings shall be initially kept bypassed using temporary loops.

Subsequently bearings shall also be included in the flushing circuit.

After completion of oil flushing the oil used for flushing shall be drained. Bearings shall be inspected

and cleaned.

Recommended fresh oil shall be topped up in the tank as per OEM manual.

Following inputs required for acid cleaning and subsequent oil flushing.

Availability of DM Water and Service Water.

Availability of following chemicals:

Hydrochloric Acid 30% Min ( IS : 265 : 1993 )

Rodine 213 SPL as inhibitor

Sodium Nitrite

Liquor Ammonia 25% ( IS : 799 – 1990 )

Lime Powder ( IS : 1540 : 1990 -Part II )

Availability of adequate number of wooden plugs

Availability of Service Air

Availability of required grade and quantity of lub. oil

Availability of L.T. Power Supply

Availability of Lab service for efficiency test of inhibitor and for testing of Moisture & Mechanical

impurities in oil .

Availability of adequate lighting and telephone facility in lub oil flushing area

Availability of manpower with tools and consumables like cloth etc

Availability of portable centrifuge / Electrostatic Oil Filtration unit.

Precaution to be taken for fire safety .

Requirement of cooling water if thermal shock  is necessary.

ACID CLEANING ( Soaking method ) -BHEL

The dissembled pipeline pieces are filled with DM water and flushed few times. It is ensured that

there is no leakage through the wooden plug provided at one end of the pipe.

5% Hydrochloric acid with 0.2% inhibitor ( Rodine 213 SPL ) is filled in the pipes. Efficiency test of

the inhibitor is done prior to its use as per NACE procedure.

The solution is allowed to soak in the pipes for 4 (four) hours and then drained in a safe place and

neutralized. This is then disposed of with plenty of service water.

The pipes are flushed with DM water for 5 to 10 minutes.

The pipes are again filled with 2.0% Sodium Nitrite & 5.0% liquor ammonia solution. The solution is 

allowed to soak for 30 minutes and then drained.

The pipe is rinsed with DM water till pH of discharged water is between 6.5 and 7.5.

The internal surface of the pipes is dried with dry compressed air.

The lines are filled with lub. oil and uniform oil film is achieved through out the internal surface of

the pipe. The ends of the pipes are kept properly capped till the pipes are reassembled.

XXX- All the operation is done at water treatment plant because acid handling facilities will be better

There. If that facilities are not there then temporary facility to be developed at site as acid mixture

Cannot be discharged in the drain.

continued to part -v


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BOILER FEED PUMP ERECTION AND COMMISSIONING PART-III ABC OF THERMAL POWER PLANT

PART –III

Continuation from PART-II

Placement of pump pedestal  & grouting with ready mix grout.

Mounting of pump on the pedestal

Mounting of booster pump & alignment with BFP motor

BP/BFPs bearings checking, clearance setting and box-up

Mechanical seals checking/inspection and mounting of BP/BFP (Both for DE/NDE)

Alignment of pump with hydraulic coupling complete.

Completion of mechanical  seal cooling water lines, Auxiliary cooling water line  ,placement of coolers after Hydraulic testing.

Installation of seal water cooler.

Following erection checks to be carried  during the process of erection.

Position  & elevation of foundation (elevation within+5mm/-10mm). Check that depth and verticality of each pocket is OK.

Distance from fixed reference axis e.g. A-row, B-row Columns. (1mm / metre,  5mm Max.)

Marking of equivalent axes on foundation.

Blue matching of the packers to have a minimum of 80% of contact area between each other and with bottom of foundation frame.

Ensure that machined surfaces and surfaces exposed to grouting in foundation frame    

    

are free from paint, rust, scale.

Fitting of half couplings to all equipment after ensuring corresponding fits.  For taper coupling,

ensure around 80% contact between shaft & coupling.

Blue matching the top surface of foundation frame with corresponding bottom surfaces of

equipment with around 80% contact.

Measure distance between  coupling half faces of

               -Booster Pump and motor

               -Motor and Hydraulic coupling

              - Hydraulic coupling and Main Pump.

Alignment (lateral and angular) between Booster pump & Motor, Motor & Hydraulic coupling,

             

Hydraulic coupling & BFP. Measure distances between coupling flanges.

Ensure that the entire pipeline is supported by permanent supports before making the last four    

Joints. (i.e  Booster Pump suction and discharge and Main pump suction and discharge).

Distances and alignment readings between coupling half faces of BFP & Hydraulic coupling,

Hydraulic coupling & motor, Motor & Booster pump after completing pipe connections.              

We have till date described only MDBFP for TD BFP except prime mover every thing will be same. Next Part i.e PART IV we will discuss about TDBFP in brief.

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