va1 nhi 00100 m m1c man 0003 rev1 coal mill operation manual

7/21/2019 VA1 NHI 00100 M M1C MAN 0003 Rev1 Coal Mill Operation Manual

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DOCUMENT SUBMISSION STATUS: FC

1 2013-03-25 4 paragraphs be modified whichpainted yellow

Zhang Pengxiao Li Hongsheng Yu Tingwei

0 2012-12-01 Zhang Pengxiao Li Hongsheng Yu Tingw ei

REV DATE DESCRIPTION DRWN CHKD APPN

OWNER OWNERS CONSULTANT

EPC CONTRACTOR EPC CONTRACTORS CONSULTANT

PROJECT TITLE

VUNG ANG 1 THERMAL POWER PLANT 2 x 600MW

CONTRACT No. 251209/LILAMA-NHI

DRAWING TITLE

Coal Mill Operation ManualFUNCTION NAME SIGN DATE

DRWN Zhang Pengxiao 13-03-25

CHKD Li Hongsheng 13-03-25

SUB-CONTRACTOR

APPD Yu Tingwei 13-03-25

DOCUMENT No.

VA1-NHI-00100-M-M1C-MAN 0003SCALE REV

1

VIETNAM OIL AND GAS GROUP (PVN)POYRY ENERGY LTD

VIETNAM MACHINERYINSTALLATIONCORPPORATION (LILAMA)

FICHTNERGmbH & Co. KG

NORTHERN HEAVY INDUSTRIES GROUP CO.LTD


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Vung Ang I Thermal Power Plant 2600MW Coal Fired Project

C20400.00 SM-2Coal Mill Operation Manual

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Content

1. General

1.1 Principle of operation

1.2 Mechanical instruction

1.3 Instruction of control system

2. Preparation before Preoperation

2.1 Visual inspection

2.2 Pipeline inspection2.3 Inspection on electric and instrument

2.4 Mechanical inspection

2.5 Charging lubrication and grease

2.6 Manual inspection

3. First Operation (preoperation)

3.1 General principle

3.2 Special regulations for several devices

3.3 Inspection after first operation

4. Operation (ball charged)

4.1 First step4.2 Second step

4.3 Third step and Fourth Step

5. Inspection before Operation

6. Startup of Coal Mill without Coal

6.1 Startup of the first coal mill after the combustion of fuel

6.2 Startup of coal mills without coal except for the first coal mill

7. Startup of Coal Mill with Coal (After Abnormal Stop or Tripping

Operation)

7.1 Startup of the first coal mill (without the other coal mills)7.2 Startup of the other coal mills

8. Shut Down

9. Emptying the Coal Mill

9.1 Partial emptying

9.2 Complete emptying

9.3 Sign when no coal in the coal mill

9.4 Sign when overload

9.5 Ball charge during operation


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Attachments:

1.Check Sheet for non-load operation of main motor (without coupling)

2.Trail Run Check Sheet for main motor (connected to ball mill)

3.Check Sheet for ball charging test operation


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The shell comprises a shell which is rolled and welded, and two heads

which are welded on the shell. Wear-resistant linings are installed inside the

shell and the heads, and the steel balls can be driven by the linings.

1.2.2 Hollow shaft

The hollow shaft is a hollow body which is fixed on the heads by bolts.

It has two functions:

(1) The hollow shaft can be used for air supply, coal feed and mixture

discharge of air and pulverized coal

The heat air gets into the coal mill through the center pipe which is

rotated by beam. The inner side of the beam is fixed on the lining, and the

outer side is supported by roller bearings outside a heat-air inlet case.

The coal is sent into the shell by helical laminaes which are fixed

outside the center pipe through protective chain.

(2) The hollow shaft can rotate the shell with the coordination of sliding

bearing.

1.2.3 Bearing

The structure of the bearing can compensate the sag of the coal mill with

loads. The bearing is made of wear-resistant metal, and can avoid damages.

The bearing pedestal is formed by welded steel components.During lubrication, the oil is transmitted by a hydraulic drive device:

- During high pressure, the oil is transmitted under the hollow shaft to

float the hollow shaft.

- During low pressure, plenty oil is transmitted onto the hollow shaft for

cooling.

The oil is transmitted under the hollow shaft for lubrication.

1.2.4 Seal system

During operation, the coal mill is in positive pressure. Thus, a special

connecting component which is used for preventing the pulverized coal from

getting into the outside air is arranged between the fixing components and

rotating components of the hollow shaft.

The connecting component is a flange made of composite material,

which is stuck to the smooth component.

The seal air fan provides the opposite pressure to avoid the leakage of

pulverized coal.

1.2.5 Classifier


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The dynamic classifier is assembled with variable frequency motor the

frequency of which can be changed by the frequency converter. Therefore,

the speed of the rotor blades of the classifier can be changed between 0

150r/min to change the fineness of the pulverized coal.

1.2.6 Drive device

The drive device is used for driving the coal mill, and the power is

provided by motor. The speed of the motor is reduced by speed reducer. The

output end of the speed reducer is used for driving the center shaft of the

pinion, and then the pinion meshes the girth gear to drive the shell.Automatic jet lubrication is used on the pinion and girth gear, and spray

lubrication is used on speed reducer.

1.2.7 Inch device (low-speed drive)

The inch device can drive the coal mill with the 1/100 speed of the rated

speed during maintenance and stop. Thus, specified position of the stop of

the coal mill can be achieved.

1.2.8 Sound-proof shield

A sound-proof shield is installed because of the noise made by the coal

mill. The shield is made of structural steel with a layer of mineral wool

inside.1.2.9 Ball charge system

The ball charge system can charge balls into the coal mill without stop.

Each coal mill is provided with one ball charge system.

1.2.10 Inert system

Inert system is used for transmitting steam into the coal mill during stop.

1.2.11 Fire-extinguishing system

This system is used for extinguishing fire. When the fire alarm rang out,

the system can spray fire fighting steam into the coal mill.

1.3 Instruction of control system

1.3.1 The temperature control of the blast-coal mixture at outlet of the

classifier

The temperature control can be achieved by adjusting the opening of

heat and cool air baffle plates. The temperature of the pulverized coal is

controlled by the primary air, which limits the temperature of the outlet in

certain range.


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1.3.2 Volume control of primary air

The volume control can achieve a proportion between the primary air

and the by-pass air.

The signal for transmitting the primary air is sent out by main controller:

1) The air volume through the coal mill is adjusted in accordance to the

flow rate at outlet of coal mill.

2) The volume of the by-pass air is adjusted in accordance to the flow

rate at outlet of coal mill.

1.3.3 Adjustment of coal level inside coal mill

1) The output of pulverized coal is modified in accordance to the load of

the boiler, and the coal feed volume is also modified relevantly.

2) No matter how the load of the coal mill is changed, the coal level

inside the coal mill shall retain the same.

3) The control of the coal level is achieved by the coal level detection,

which can be achieved by two ways:

- by controlling the differential pressures at two points

The pressures between two different points are detected, and are sent

to the speed controller of the coal feeder. Then the speed of the coal feeder is

adjusted to retain the same pressure at different points.- by the electric ear device

The coal level is controlled by detecting the sound signal to adjust the

volume of primary air and the speed of the coal feeder.

As a main control method of the coal level, the differential pressures

measuring device controls the coal feeder. The electric ear device is an

auxiliary control device used at the starting stage of operation to output

control signal. During the starting stage, the differential pressures is not

stable enough to provide rightful information of coal level. The signal from

electric ear device can provide a general information inside the shell to the

operator as a protection to avoid the situation of coal blockage inside or lack

of coal inside.

1.3.4 Automatic control system

The coal mill is provided with an automatic control device to guarantee

safety when error occurs during operation.

When error occurs to the boiler, at which emergency shut down is

needed, the coal mill shall be provided with other self-protection device,

such as non-stop of lubrication and start of low-speed drive.


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The inlet and outlet of the coal mill are provided with valves which can

be used for isolating the coal mill when the entire system stops.

2. Preparation before Preoperation

2.1 Visual inspection

Before start the coal mill, the following ordinary inspections shall be

carried out:

1) All parts and components shall be assembled well, and all importantdevices shall not be lost. In this case, the coal mill can be started safely.

2) No obvious damage occurs, and all devices are in good conditions.

3) No error is allowed during installation, or the installation shall be

carried out again from the start. The installation of all components shall be

carried out strictly in accordance to the instruction. The questions about the

installation shall be raised immediately during installation.

4) The sundries (such as tools, scrap iron, scrap wood, etc) are not

allowed to retain in coal mill.

2.2 Pipeline inspection

Before operation, all pipeline shall be inspected and get ready.

1) Inspection is carried out to all valves (rotation, open, and close). Then

the valves are set into the condition of opening or close in accordance to the

requirements of working condition.

2) All necessary parts (such as water and comprised air) are prepared,

and the performance (such as temperature and pressure) is checked.

3) All pipes are drained, and then the outlet valves are closed.

2.3 Inspection on electric and instrument

Ordinary inspections are carried out to the electric and instruments in

accordance to the following requirements:

1) Inspections are carried out to all wire connections (including power,

control and instruments).

2) All cables are arranged, and are assembled with bushing.


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3) Operation inspection is carried out to instrument (such as flow switch,

pressure switch, switch and baffle plate) if possible.

4) All junction boxes and control cabinets shall be open for inspection.

5) Fuse and interlock devices are disconnected for inspection separately.

6) The electric devices are disconnected with the main machines for non-

load operation to inspect the current and the rotating direction.

7) The power consumption of the electric devices is recorded when the

devices are disconnected with the main machines.

2.4 Mechanical inspection

First, the stableness of the foundation bolts for main components and

auxiliary devices are inspected.

The drive devices must be inspected. The couplings shall be

disassembled for the inspection of axiality if necessary.

2.5 Charging lubrication and grease

The cleanliness of all lubrication pipes are inspected.

The devices need lubrication, and the specification and quantity for theoil are marked in the instruction of lubrication.

Then, the charge for lubrication and grease can be carried out.

2.6 Manual inspection

Most devices shall be rotated by hand to inspect whether there is

interference or inflexibility.

3. First Operation (preoperation)

3.1 General principle

In order to execute start operation for single coal mill, the interlock

devices shall be disconnected.

The first preoperation shall be non-load operation without coal and steel

balls. Simultaneously, the coal mill shall be disconnected with the boiler, but

safety devices shall be in application.


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The instruments shall be started in accordance to procedures gradually

without using the interlock device. Device cannot be started individually

unless the instruments have been in operation for a while or all operational

parameters are stable.

Then, inspections are carried out to the operation and setting position of

the instruments.

During operation, the technical staff shall inspect the following item near

the devices:

- Temperature (such as bearings) must not be high.

- No abnormal noise exists.

- Whether the wastage of the motor is close to the value of calculation.

- No leakage (such as water, oil) occurs.

- The oil level is correct.

- Oil film thickness of the main bearing is inspected, as the coal mill

could be jacked up by operating the jacking oil pump of the main bearing.

The abnormal occurrence during the first operation should be analyzed

and solved, and make sure that there is no problem left.

3.2 Special regulations for several devices

3.2.1Bearing lubrication

The commissioning of the lubrication device must be carried out in the

manufacturer and the device cant be used without the oil, the electric heater

switch and cooling circuit shall be provided, when the oil temperature meets

the requirements, the oil pump is started and the oil condition is inspected,

(if there is no oil in one minute, the inspection to oil pump shall be ceased)

The inspections are carried out to the oil mist on the hollow shaft (the

both side are equal), and the oil return is normal.

The oil pressure of the high-pressure pump is inspected, and the raisedheight of the both side of coal mill is recorded.

The oil level in the tank in inspected, the oil level must be over the

height of pipeline and be above the minimum oil level.

The filter of the low pressure pump should be cleaned regularly.

3.2.2 Lubrication of speed reducer


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The motor is started and the inspections are carried out to the oil

condition.

The filter must be cleaned frequently.

If possible, the access eye shall be opened to inspect the spray condition

in the speed reducer.

3.2.3Lubrication of girth gear

The pressure of the comprised air is inspected and there is no moisture in

the air.

The girth gear is started for one circle regularly.

The operations of all the components are inspected, especially the

injection oil on the girth gear. The nozzle should cover the entire width of

the girth gear and the formed oil films are similar.

The jet circle and the interval between the two jets are adjusted.

3.2.4 Coal mill

Warning: the coal mill must be started without the steel ball and coal.

The sealed fan of gear cover, the motor and speed reducer are started.

The coal mill is ceased after the 30 minutes smoothly operation.The bearing temperature is monitored during the operation, if the bearing

temperature is too high, the coal mill shall be ceased, and the conditions of

race rotation and oil film are inspected by the observation door on the

bearing cap.

The vibrations of the coal mill are inspected.

The inspections are carried out to the operations of the girth gear and

main bearing.

The power equipment of the coal mill drive is observed.

3.2.5 Main electric machine of the coal mill

The bearing temperature is inspected.

The winding temperature is inspected.

The absorbed power of the electric machine is recorded.

3.2.6 Screw convey device

The frictions between the stranding cage and hollow shaft are inspected

(listening).


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The temperature of the steady bearing is inspected.

The inspections are carried out to the vibrations.

3.2.7 Trial run of dynamic classifier

The following shall be checked before the trial run:

Check the direction of the stator blade.

Check the rotating direction of the classifier motor (shall be

counterclockwise direction seen from ouotput shaft)

Check the condition of the lubricant and grease on the speed reducer

and the transmission part of the classifier.

Check the connection of the seal air pipe. Check whether theres

leakage.

Start up the variable frequency motor. The design speed of the rotor

blade on classifier is 107rad/min. The speed can be adjusted based on the

actual condition during operation. The trial run of the classifier is 4 hours.

Check the stability of the rotor blade rotation. Check the classifier

whether theres abnormal noise or vibration.

When the coal mill is put into operation, the blades of the classifier

shall be checked regularly in case theres material winding on the blade. Thegrease shall be added to the transmission part of the classifier regularly by

manual pump.

3.2.8 The operations of all the control system are inspected.

3.2.9 The raw-fuel feeder is inspected in accordance to the manufactory

instructions.

3.3 Inspection after first operation

The coal mill and auxiliary device are inspected after first operation (30

minutes at most), and the errors shall be recorded and be restored or

regulated.

4. Operation (ball charged)

The amount of steel balls is increase gradually during the operation.


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first step: A quarter of the total steel balls

second step: Two fourth of the total steel balls

third step: Three quarters of the total steel balls

fourth step: All of the steel balls.

Important hints: The rotation is carried out without coal in order to

avoid the fire.

It is very important to record the quantity of steel ball

which had been added in the coal mill.

The characters (such as absorption power, friction, oil

pressure etc.) are recorded during operation.

The coal mill should rotate for 30 minutes with the

maximum amount of load.

The first ball charge must be carried out through the access

door rather than the ball charge system.

4.1 First step

25% steel balls are added in the coal mill in the first step, the following

methods are carried out:

The access door is put upwards under the sound-proof shield

through one of the access door, the bearing lubrication system is operated

and the shell needs the brake and is locked at this site. The support bearing

lubrication is started while the brake is disengaged in order to avoid the

frictions between the metals. The grinding mediums are added into the shell

with the help of hoisting machine. The access door is fixed on the shell.

All the devices (including lubrication system and sealed fan) are started.

All the devices are inspected, especially the bearing temperature during

the operations. The coal mill is ceased and cooled after the 30 minutes

operation.The looseness of the liner bolt is inspected.

4.2 Second step

25% steel ball are added in the coal mill by the above methods and the

coal mill is started and inspected. The coal mill stops after 30 minutes

operation.


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4.3 Third step and fourth step

The entire steel balls are charged by repeating the above steps.

The inspections are carried out to the coal mill after the operation and

the errors shall be restored and regulated.

5. Inspection before operation

All the devices and components are to be ensured of the normal startup

and safe work before operation.Especially the following required inspections:

1) The actions of the coal mill and auxiliary devices, especially the coal

feeder, blower, sealed system, coal dust, air, pipe shutoff valve of air and

dust mixture and controlled blind.

2) The individual devices must be ensured to be provided with the

lubricant system, especially the oil level, pressure, temperature shall be in

accordance with the requirements.

3) The temperature, dust delivery system and air system are normal.

4) The remote control is normal.

5The warning system and safety device should follow the instructions,

the range of instruments shall be adjusted to the setting point.

6The power system such as electric machine is to be ready for the

instructions.

7) The measuring instruments, indicator and optional switch of

automatic device are in the satisfying state.

8) The enough oil is put into the lubrication system of burner during the

entire stage to ensure the smooth burning in the boiler, the boiler burning is

raised while in the trouble.

9) The steam inert system can be used while the coal mill is on fire.

Any abnormal occurrence which is not accordance with the normal

requirements shall be recorded in the device and main control room

recording, the shutting down or close watching shall be decided for the grave

circumstance and error. Thus, the responsible operator could understand the

circumstance, the allowed scope of the above circumstances and the methods

which is carried out should be recorded while overrunning the scope.

10) The no coal warning device of the coal feeder is inspected.


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11) The outlet valve of coal feeder is started.

12) The water cooling system of the lubrication device is inspected, and

the inspection is carried out to the water cooling which should pass the

pipeline.

13) The sealing system is adjusted to the starting state.

14) The sites are inspected for the door and baffle plate of the entire air

and pulverized coal pipe.

6. Startup of coal mill without coal

6.1 Startup of the first coal mill after the combustion of fuel

The meaning of coal mill without coal is that the coal mill has coal,

but after the period of stall, the amount of coal may reduces because of the

wind.

The following advises are applicable to the thermal and cool state coal

mill, the difference is that the operation time of cool state coal mill(the stable

adjustment for flow rate and temperature) is longer than the thermal state

coal mill , the stable grind time must be considered.

The operator must ensure the sufficient load of boiler before thecombustion of coal in order to avoid the danger which could be caused by

the fuel in the boiler during the period of startup.

The first startup must be careful. The boiler must work on the upmost

ability of the fuel device. Then, as the short instability of the combustion, the

amount of reduced fuel is ensured by text in order to avoid the danger to

boiler.

After all the chapter 3 requirements are achieved and the interlocking

mechanism can be used and be operated completely, the coal mill can be

started. The startup of coal mill without coal and the restartup are carried

out in accordance to the following steps.

6.1.1 The control of all the milling system is installed on the automatic

control procedure.

6.1.2 The control baffle plates which are provided with the air system, coal

dust pipe, raw coal pipe and ball charge system are closed.


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6.1.3 The temperatures of all the devices are inspected.

6.1.4 Startup of lubrication system

Note: The low pressure pump of the main bearing lubrication system is

started before the last several hours startup. Under the normal conditions, the

pump keeps working even in the period of stop. The pump stops working

only while the longtime stop and maintenance.

6.1.5 The low-speed device is closed after a few minutes startup, if the doubt

about the rotating flexibility of coal mill is there.

6.1.6 The output system of instrument which measures the pressure and coal

level is inspected.

6.1.7 The fire protection system of coal mill can follow the working

instructions.

6.1.8 The sealed air fan of the gear cover is started.

6.1.9 The valve under the raw coal bin is opened.

6.1.10 The burner is combusted by fuel oil while the startup of coal mill is

ensured.

6.1.11 The primary air fan is started.

6.1.12 The air flow rate and pressure in the bellows are inspected.

6.1.13 The inspection is carried out to the primary air temperature which

should be higher than 150at the air preheater outlet.

6.1.14 The coal mill is started by the automatic procedure.

6.1.15 The inspections are carried out to the primary air volume (include the

air volume of coal mill and bypass) which should be more than the minimum

flow rate.


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6.1.16 The automatic purge device of the coal level detection system is

inspected.

6.1.17 The temperature of the classifier setting value is inspected.

6.1.18 After the classifier outlet temperature reaches to the enough degree

(110) for 2 minutes or the coal mill is started for nine minutes, the raw-

fuel feeder is started and is set in the state of coal supply.

6.1.19 The temperature of the classifier outlet is monitored, if the

temperature is abnormal, the flow rate of raw coal must be adjusted, the

stability and performance of the combustion are inspected and the inspection

is carried out to the secondary air volume of burner in order to reach the

good combustion state.

6.1.20 When the electric ear sign is lower than 35% for two minutes, the

coal level is controlled by coal feeder

6.1.21 The coal mill load is added progressively, controlled by automaticprocedure and continued to increase in accordance with the control

requirements, the secondary air passed burner is inspected.

6.1.22 The purge wind should purge the detecting device of coal level

control system at regular intervals.

6.2 Startup of coal mill without coal besides the first coal mill

The general inspection is carried out to the coal mill in accordance with the

regulations of the third chapter and fifth chapter, before the startup ofremaining coal mill which follow the first coal mill.

The boiler load is inspected and the steps in the 6.1 paragraph are carried

out after the boiler program permits the startup of coal mill.

7. Startup of Coal Mill with Coal


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The coal mill is started under the coal feeding conditions (the abnormal stop

or devices trip), before the startup, the inspections are carried out to the coal

mill in accordance with the requirements of the fifth chapter.

The boiler load is inspected and the following steps shall be carried out

after the program permits the startup of coal mill.

7.1 Startup of first coal mill (no operations of other coal mills).

7.1.1 All the controls to the relevant coal mill milling system are set on the

automatic control program.

7.1.2 Startup of coal mill burner, the stability of firing combustion is

inspected.

7.1.3 Startup of primary air fan.

7.1.4 The works for coal level detection system are inspected.

7.1.5 Inspections are carried out to the lubrication system.

7.1.6 Startup of coal mill.

7.1.7 The temperature of classifier outlet is normal. The primary air flow is

higher than the minimum value.

7.1.8 Monitoring is carried out to classifier temperature and the adjustment

can be carried out to the raw coal flow if the temperature is abnormal.

7.1.9 If necessary, the manual operation could be carried out to keep thecontrol normal and eliminate the errors which could effect the coal mill

operation.

Warning: If the error of coal feeder makes the stop of coal mill and the coal

feeder can not be used at once, the restart-up of coal mill is prohibited.

7.2 Startup of remaining coal mill.


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The protective measures are carried out before the operations in

accordance to the steps of 7.1 sections to start oil burner which fits the coal

dust burner.

The oil combustion load must keep the combustion stable.

8. Shut down

The boiler load requires that the coal mill can be shut down systematically

or by force in the emergency, such as a sudden tripping which is caused by

the startup of safety interlock.

When the coal mill shuts down, the coal mill inside is full of pulverized

coal (all or part of pulverized coal), the coal mill can be operated continually

by the low-speed device which should operate about 6 hours to avoid the fire

in coal mill.

If the time of stop is short (less than 40 hours), the coal mill can be shut

down with full load.

If the time of stop is long (more than 40 hours), coal mill can be shut down

after10 minutes operations without the coal feeding to keep the coal mill

empty.Before the maintenance, the coal mill must be empty, when the coal

activity is high, coal mill must be emptied in the inert gas conditions

(mixture of pulverized coal, primary air and steam).

While the low-speed device or steam inert system can not be used, the coal

mill can be shut down after it was empty.

The coal mill with coal can be shut down by low-speed device because of

the tripping.

During the period of stop, the shell temperature of milling system must be

kept under observation in order to find the abnormal occurrence or ignition

danger.

The coal mill must combust before the stop operation, otherwise the fuel

burner is operated, and all the fuel burner must be kept on working by force

until the pulverized coal pipeline is clean.

9. Emptying the Coal Mill

9.1 Partial emptying (10 minutes)


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The operations are carried out in accordance with the following steps:

9.1.1 The pulverized coal burner is closed, the combustion of coal mill

adopts fuel burner and the load of coal mill could keep the combustion stable.

9.1.2 The stability of the fuel burner combustion is inspected.

9.1.3 The primary air flow is controlled by hand.

9.1.4 The coal feeder is shut down and the outlet gate of coal feeder is closed.

9.1.5 The primary air flow is reduced progressively to the permissible

minimum flow.

9.1.6 The temperature of the classifier outlet is monitored and the

temperature is stabilized on the normal value by hand.

9.1.7 After 10 minutes of shutting down the coal feeding, the primary air

gate is closed.9.1.8 The main motor of coal mill is closed and the low-speed motor is

started.

9.1.9 Startup of the steam inert system (last 3 minutes).

9.1.10 The stop valve of pulverized coal is closed.

9.1.11 While the coal mill is shut down, the fuel burner can be closed after

make sure that other burners can keep the combustion stable.

9.2 Complete emptying

9.2.1 The pulverized burner is closed, the burner combustion is adopted and

its load should keep the combustion stable.

9.2.2 The stability of fuel burner combustion is inspected.


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9.2.3 The primary air flow is controlled by hand.

9.2.4 The coal feeder is shut down and the outlet valve of coal feeder is

closed.

9.2.5 The heat air baffle plate is closed, the steam valve is opened.

9.2.6 After 30 minutes stop of the coal feeding, the seam valve and primary

air gate are closed.

9.2.7 The main motor of the coal mill is shut down.

9.2.8 The seal air fan is shut down.

9.2.9 The stop valve of pulverized coal is closed.

9.2.10 While the coal mill is shut down, the fuel burner can be shut down

after make sure that other burners can keep the combustion stable.

9.3 Sign when no coal in the coal mill

The assurance is confirmed by the following observations after the stop.

9.3.1 Low coal level is detected by coal level control system.

9.3.2 High noise level.

9.3.3 The difference in temperature between the coal mill inlet and classifier

outlet has a sharp drop.

9.4 Sign when overload

9.4.1 High coal level is detected by coal level control system.

9.4.2 Low noise level.

9.4.3 Pressure drop of the coal mill is very high.


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9.4.4 Absorption power increases.

9.5 Ball Charge during operation

9.5.1 Since the steel balls will be worn out during operation, new ones shall

be charged into the shell regularly in order to fulfill the output capacity and

the PC fineness.

9.5.2 During operation, the steel balls are charged into the shell by ball

charging device when the the operation of the coal mill is not stop.

9.5.3 If tge current of the main motor is increased or the output is decreased,

the new steel ballsshall be charged. The quantity of the new steel balls is

based on the current-quantity curve chart during the test of the steel ball

charging.

9.5.4 When the new steel balls are charged into the shell by ball charging

device, only the50 steel balls is needed. Each charge shall be less than 50kg.

If the charging quantity is large, then it shall be separated by several times in

order to avoid damage to the ball charging device or blockage of the pipe.

9.5.5 The valve of the ball charging device is controlled by the local control

cabinet of the ball charging device. First, 50kg of steel balls shall be added

to the ball container from the 13.7m operation floor manually. Then open the

upper layer valve. When all the steel balls are into the ball container, the

upper layer valve is closed. After that, open the lower layer valve so that the

steel balls inside the ball container can be dropped into the shell through the

pipe. Finally, close the lower layer valve. The above procedure is a

complete ball charging procedure for one time. The name and the instruction


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Page 22 of 22

of the equipment refers to VA1-NHI-00100-M-M1C-DGA 2012 BALL

CHARGING DEVICE.

9.5.6 If new steel balls are still needed to charge, please repeat item 9.5.5.


24/29

Check Sheet for Non-load operation of main motor (without coupling)

Unit System Equipment NameMain Motor of Ball Mill

KKS Test Date

Rated Voltage Rated Current

Rated Speed Running Current

Megger Value of motor before run

M

Direction of Rotation

Measurement and ToolInsulation Resistance: measured by operator at site with megger (megohmmeter).Vibration velocity: measured by operator at site with vibration meter.Temperature: indicated on local control cabinet or DCS.

Vibration velocity

Time Location

Direction

Main Shaft

End

Countershaft

End

axial direction mm/s

Vertical mm/s

horizontal mm/s


Vertical mm/s

horizontal mm/s

Temperature Ambient Temperature

Time

Location

0.5h 1h 1.5h 2h 3h 4h DCS

Reading/Local

Reading

1

2

Winding

Temperature

3

1BearingTemperature 2

Oil Temperature

Measured by Company Signature

LLM/Vendor Owner/Consultant Signature


25/29

Trail Run Check Sheet for Main Motor (connected to ball mill)

Unit System Equipment NameMain Motor of Ball Mill

KKS Test Date

Rated Voltage Rated Current

Rated Speed Running Current

Megger Value of motor before run M

Measurement and ToolInsulation Resistance: measured by operator at site with megger (megohmmeter).Vibration velocity: measured by operator at site with vibration meter.

Temperature: indicated on local control cabinet or DCS

Vibration

Time Location

Direction

Main Shaft End Countershaft End


Vertical mm/s

horizontal mm/s


Vertical mm/s

horizontal mm/s

Temperature Ambient Temperature

Time

Location

0.5h 1h 1.5h 2h 3h 4h DCS

Reading/LocalReading

1

2

WindingTemperature

3

1Bearing

Temperature 2

Oil Temperature




26/29

Check Sheet for Ball Charging Test Operation (1)

Unit System Equipment NameBall Mill

KKS Test Date

Measurement and Tool

Jacking Height: measured by operator at site with dial indicator.

Pressure at high-pressure pump: indicated on outlet pressure gage of lube station.

Jacking Height of Shell & Pressure of High-pressure oil

Jacking Height

mm

Pressure of High-pressure oil(MPa)Item Continuousworking

period Drive

End

Non-

DriveEnd

DE

instantaneouspeak value

DE

stablevalue

NDE

instantaneouspeak value

NED

stablevalue

Non-load

Steel Ball

Stationary

State

1/4 SteelBall Load

StationaryState

2/4 Steel

Ball Load

Stationary

State

3/4 SteelBall Load

StationaryState

Steel BallLoad

during

normaloperation

StationaryState




27/29


Unit System Equipment Name

Ball Mill

KKS

Measurement and Tool:

Current of main motor: indicated on DCS or other indicator

Bearing Temperature: measured by operator at site with thermodetector.

Current of Main MotorA

Item Continuous

working period

Current

Non-load Steel balls 30min

1/4 Steel balls load 30min



Steel Ball Load during

normal operation

30min

Bearing Temperature Ambient Temperature

Bearing of Pinion Bearing of SpeedReducer

Bearing of conveyingdevice

Item Continuousworking

period InputEnd

Output End InputEnd

OutputEnd

DE end NDE end

Non-load Steel balls 30min





normal operation

30min




28/29


Unit System Equipment Name KKS

Measurement and Tool:

Vibration velocity: measured by operator at site with vibration meter.

Vibration velocity

mm/s

Bearing seat of pinion shaft extension ofspeed reducer

Bearing Seaconveying devic

Item Continuousworking

period

Direction

DE NDE Inout end Outputend

DE NDE

axialdirection

Vertical

Non-load steel ball 30min

horizontal

axial

direction

Vertical

1/4 steel ball load 30min

horizontal

axial

direction

Vertical


horizontal

axialdirection

Vertical


horizontal

axial

direction


normal operation

30min

Vertical




29/29


Unit System Eqipment Name Ball Mill

KKS Test Date

Measurement and Tool

Temperature: indicated on local or DCS.

Temperature of main motor and main bearing Ambient Temperature

WindingTemperature

Bearingtemperature

of mainmotor

Oiltemperature

Mainbearing

of ballmill

Outlettemperature

of lubestation

item Continuousworking

period

1 2 3 1 2 1 2

Non load 30min

1/4 load 30min

2/4 load 30min

3/4 load 30min

Normal

loadduringoperation

30min



va1 nhi 00100 m m1c man 0003 rev1 coal mill operation manual

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