ID ,FD ,PA FAN COMMISSIONING OF BOILER PART -X ABC OF THERMAL POWER STATION

Pre-commissioning Check List/activity to be carried out

Check the erection protocol /log sheet for foundation bolt tightness , clearance with respect to

impeller hubs ,blades casing etc.

Check fan shaft level , check the coupling arrangement , Different gaps measurement in protocol etc.

Check the calibration of power cylinder for blade pitches etc.

Once all the protocol checks are over then check the connection of water line and oil line at different

places.



Check the inlet /outlet duct position immediately before and after fan.

Check the commissioning of outlet dampers and inlet guide vanes.

Check the freeness of the rotor by hand before connecting to the motor.

Remove all temporary supports from inside the duct which comes under the flow path of fan

Agencies working in the boiler area / associated ducting system are informed about the test / cleared

from the test area (As per the actual requirement). Specially for the first time otherwise dust storm

can put any body into trouble .

All loose materials around the fan area are cleared.

Required approach stair cases, platforms and hand rails are erected prior to testing.

Erection of the following are completed.

Lube oil system

All the lube oil control oil pipe lines erected ,cleaned and flush as per procedure (acid cleaning)

described in my earlier blog 

DM.C.W lines for HT motors and oil coolers

Suction and discharge duct and their connection with fan.

L.T./H.T switch gears required for the fan.

Fan casing, Suction / Discharge ducts are cleared off men & temporary materials.

All permanent supports and guides of fan & duct  are erected.

All local  instrumentation of lube-oil system, motor and fan are erected. (Required list to be prepared

at site) )Pressure and temperature indicators are duly calibrated)

Remote indication at control room are made available (List to be prepared at site)

Recommended Blade pitch operation (for FD & PA fan) and inlet damper operation for ID fan)

verified at local and the same ensured from remote for correct opening / closing with respect to

position indicator at local and remote. Free movement of Blades & inlet dampers are ensured.

ACW lines are flushed and connected to the respective inlet points.

 ACW inlet / outlet connections to ID fan sleeve bearings are connected as per the indicated

markings.

 Ensure variable frequency Drive (VFD) system is made ready (In case of ID Fan for operation of the

Fan. (Refer to the procedure enclosed in Section 10.0.)

Insulation resistance of the motor measured and ensured that the values are at satisfactory level.

Final commissioning

Start lube-oil system and establish oil circulation at recommended oil pressures (Both lube-oil and

control oil, which ever is applicable)

After obtaining clearance from all agencies, start the motor in decoupled condition and check the

direction of rotation. If  direction found reverse, change the direction of rotation of the motor.

Refer to section 10.0 for details regarding checking and commissioning of VFD system. In addition

commissioning manual of VFD issued by supplier to be followed in the commissioning of VFD

system.

Start  the motor once again and put under 8 Hrs trial run (FD and PA motors). In the case of VFD

synchronous Machine, put the machine under 4 Hrs trial through channel I and under 4 Hrs trial

through channel II.

Performance of the motor to be monitored by logging load current, vibration and temperatures of

bearings and windings, whichever applicable.

After satisfactory completion of drive trial run, drive and the fan are coupled.

Start the fan and put under 8 Hrs trial run.

Blade pitch for FD and PA fan to be at minimum before starting the fan and after starting, fan to be

slowly loaded up to around 10-15% (Exact loading of the fan to be decided at site)

For ID Fan, keeping the inlet damper at minimum, Fan started and loading to be gradually increased

to 10-15% (Exact loading of the fan to be decided at site)

During 8 Hrs trial run, Fan performance observed by logging load current, vibration, temperatures of

the bearings, parameters of lub-oil system VFD system and draft values in PA,SA and Gas circuits

covered in single fan running condition.

Following parameters are recorded every hour in log sheet.

a. Starting time . b. Closing time (i.e time taken from running to standstill). c. Vane angle

d. Current and Voltage  e. Discharge Pressure . f. Motor Winding Temp . g. Oil level leakage of

oil. h. Cooling water flow Pressure and temperature. I. Lube oil and control oil Pressure and

temperature. j. Any other observation k. Vibration on all bearings.

All the fans commissioning process is same except the duct connection to be done . For FD and

PA suction chamber with silencer head should be available and discharge goes to furnace through

SAPH and PAPH.

For ID fan suction can be taken from ESP outlet bar or ESP can also be taken on line if ESP Air

tightness test is over . Discharge can be up to chimney. 

Above drawing shows the area to be covered during trial run. But it will be best if total ducting work

gets completed before the trial run.

 PA fan distribution up to mill including PAPH.

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ID,FD,PA FANS COMMISSIONING OF BOILER PART -X -ABC OFTHERMAL POWER

In my last blog I have discussed about the lube oil supply unit for fans ,Air heaters and Mills.

Construction features and item including control and instrument in the lube oil system is

more less same .Therefore observing one lube oil commissioning will help to learn the other.

Now we will discuss the commissioning of FANS. The commissioning of six numbers of

FANs are similar however system requirement for commissioning of FANs are different. We

will discuss the common system requirement and the individual requirement of FANs.

Induced Draft Fan

No of Fan                                :  2

Flow   (Approx)                       : 558.2 cu.m/Sec

Pressure (Approx)                  :  485 mmwc

Temperature                           :  150⁰C to 154 ⁰C

Drive                                       :  Motor

Speed                                     :  580 RPM

Motor Rating                           :  3650

Control                                    :  Inlet Damper plus variable  / Hydraulic coupling

                                                   Frequency Drive. (VFD).

Forced Draft Fan

No. of Fan                                                   :  2

Flow    (Approx)                                          :  246 cu.m/Sec

Pressure    (Approx)                                    : 351 mmwc

Temperature                                               :  50 degree C

Drive                                                            : Motor

Speed                                                           : 980 RPM

Control                                                         : Variable Blade Pitch control.

Motor Rating                                               :  1175 KW

The boiler   is also equipped with primary air fan, which form a part of the coal preparation a

and firing system.

PRIMARY AIR FAN

 

No. of Fan                                               :  2

Flow       (approx)                                   :  170.5 cu.m/Sec

Pressure   (approx)                                 :  1183 mmwc

         

Temperature                                           :  50 degreeC

Drive                                                       :  Motor

Speed                                                      :  1480 RPM

Motor Rating                                          :  2450 KW.

Control                                                   :  Variable Blade Pitch

                                                                  control.

(****- All the values given here are of 500MW set of BHEL Make.)

 

All the fan are mounted on concrete deck with suction and discharge duct. Connected to the

Fan flanges. FD Fans and PA fans are provided with Silencer at the suction duct. 

Regulation of Fan from no load to full load is performed by changing the pitch angle of blade

profile on all blades simultaneously during operation. This is achieved through a

sophisticated servo mechanism (Hydraulic Servo Motor externally actuated by a power

cylinder and forced lube-oil system.

In the case of ID Fan, the equipment is driven by variable frequency drive motor coupled

with soft coupling. The regulation of the fan is effected through the inlet dampers located at

the inlet of the fan and variable speed by VFD.

In FD and PA fans, the rotor is supported in antifriction  bearings and cooled by forced

lubricating oil. A thrust bearing is provided to absorb axial loads. Thermometers (RTD &

TI ) are provided in the bearing housing for temperature monitoring.

In ID Fan, the bearings are while metal sleeve type with forced oil lubrication. Fixed bearing

near drive end is designed to absorb the Axial forces. Thermometers are provided in the b

earing housing for temperature monitoring.

Respective O & M manuals to be referred for typical drawing of each fan.

Common Facilities Required for Fans

Safety Rules clearance certificate to be signed at site by all concerned engineers

before commissioning of the fans.
 

It is proposed to commission the fans as per the following proposals.

Oil flushing of lube-oil system is completed in all respect and fresh oil has been filled in the tank.(****)

 (***)- Presently using electronic centrifuge flushing oil can be cleaned up to required

parameter and can be reused as fresh oil. 

Trial run of H.T. Motor carried out for  8 Hrs as per agreed protocol.

Auxiliary cooling water line connected ,flushed with all instrumentation and ready for use.

LT /HT Power supply available and Minimum protection is tested and ready.

Availability of lighting, communication facility at the test area.

 Availability of portable fire extinguishers

Servo control mechanism / VFD system / Hydraulic coupling commissioned and calibrated.

Instruments for Pressure ,Temperature , Blade Pitch Position etc are commissioned and put

in place.

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ID, FD,PA FANS,AIR HEATER , MILLS LUBE OIL BOILER COMMNG PART IX -ABC OF THERMAL POWER

I am going to describe the commissioning procedures of ID<FD and PA fans for a boiler.

As  the procedure of commissioning is more or less same therefore commissioning

procedure will be common.

While writing  it was felt that before start commissioning procedures of fans ,the

commissioning procedures of lubrication units to be discussed . As these lubrication units

are more or less same for all the fans therefore any one can be discussed out of all

lubrication units. These units are also same for AH (air heater) and Mills. So if we discuss

one lubrication unit then other units are automatically covers.

Number of lubrication units used in Boiler

-  One Number /Fan /unit – Total requirement is six numbers ( ID-2 ,FD-2 and PA-2)

-  One Number / Mill /unit- Total number 9 or 10 as per number of Mills.

-  Two Number /Air Heater/Unit ( Support & Guide bearing) – Total 8 numbers ( SAPH and

PAPH).

Rotary equipment in Boiler like Fans ( except scanner and seal air) ,Air heaters and Mills

are provided with external lube oil system for supplying lubrication to the bearings. This

lubrication units also serves as coolant for equipment bearings.

The external lubrication system consists of Oil Tank , Pumps (02 nos) , suction

strainers ,duplex filters , oil coolers , connecting pipelines valves (isolating and relief),

instrumentation for local measurement and remote logic and measurement etc. Logic of

auto changeover and emergency change over by hand are also been provided.

Generally all  the lubrication unit comes as a skid (i.e totally fabricated with input / output

connection at the end.

Our main objectives will be clean the lube oil unit pipeline and associated equipment free

from dust and foreign materials so that lube oil going to bearing  is very clean.

All the equipment and pipelines to be erected as per drawing . Drain oil pipes ( from Bearing

to tank should have minimum slope towards  the tank).

Site erected pipelines are dismantled from flange joints ,end connection etc to make it

smaller pieces. Then these pipelines are manually cleaned and air blown. Then wooden

plugs placed in one end tightly and flushed with DM water number of times to check that      

there is no leakage from wooden plugs.

 All the coolers to be hydro tested 1.5 times  of the design pressure.

 Following chemicals are required for acid cleaning of pipeline ( soaking method)

 a. HCL 30% b. Rhodine 213 SPL  c. Sodium Nitrite d. Liquor ammonia 25%

 e. Lime Power.

 

5% hydrochloric acid with 0.2% inhibitor ( Rodine 213 SPL) is filled in the pipes.

The solution is allowed to soak in the pipes for four hours and then drain to pit and with

plenty of service water and lime to neutralized.

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

Pipes are again filled with DM water containing 2.0% sodium nitrite and 5% liquor

ammonia . The solution is allowed to soak for 30 minutes and then drained to pit.

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

 The internal surface is dried with compressed air.

 The line filled with lube oil and then drain . This will fill the pipeline with a uniform fill of oil.

 ( Any cutting ,welding after acid cleaning of the pipe is strictly prohibited. )

 Oil Flushing is carried out in two stages

 Stage-I - without bearing in circuit

 stage –II – Bearings included in the flushing circuit.

 The Oil Tank is filled with recommended oil

 Direction of motor is checked by dismantling the pump and again assembled.

 Centrifuge also placed in position and connected with temporary lines.

 Start the pumps with recirculation valves wide open.

 Pressure to lube oil lines is brought to 1.0 to 1.5 kg/cm2 by throttling recirculation valve.

 The system is checked for leakage. Flushing should continue with one pump in service .

Both the pumps should be tried alternatively. Centrifuge should be on service to clean the

oil.

Time to time DP filter is checked and if required cleaned/replaced.  DP across filter should

be less than 0.2 Kg/cm2

Mechanical impurities should be less than 100 ppm in flushing oil for three consecutive

reading taken at interval of four hours.

Before taken Bearing into circuit clean the oil tank again so that all sludge accumulated

during stage –I flushing gets cleaned.

All the measurements during commissioning to be recorded and protocoled.

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