va1 nhi 00100 m m1c man 0003 rev1 coal mill operation manual
TRANSCRIPT
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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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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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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.
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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
axial direction 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
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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
axial direction mm/s
Vertical mm/s
horizontal mm/s
axial direction 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
Measured by Company Signature
LLM/Vendor Owner/Consultant Signature
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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
Measured by Company Signature
LLM/Vendor Owner/Consultant Signature
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Check Sheet for Ball Charging Test Operation (2)
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
2/4 Steel balls load 30min
3/4 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
1/4 Steel balls load 30min
2/4 Steel balls load 30min
3/4 Steel balls load 30min
Steel Ball Load during
normal operation
30min
Measured by Company Signature
LLM/Vendor Owner/Consultant Signature
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Check Sheet for Ball Charging Test Operation (3)
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
2/4 steel ball load 30min
horizontal
axialdirection
Vertical
3/4 steel ball load 30min
horizontal
axial
direction
Steel Ball Load during
normal operation
30min
Vertical
Measured by Company Signature
LLM/Vendor Owner/Consultant Signature
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Check Sheet for Ball Charging Test Operation (4)
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
Measured by Company Signature
LLM/Vendor Owner/Consultant Signature