book

1. Index No. 37-FA10871S-J0201-17
Rev. C
印度古德洛尔电厂工程 施工图设计
IL&FS Cuddalore Power Project DETAIL DESIGN
PULVERIZED COAL PREPARATION SYSTEM
DESIGN DESCRIPTION
Plant: IL&FS Cuddalore Power Project
Owner
IL&FS Tamil Nadu Power Company Limited
Owner’s Engineer Fichtner Consulting Engineers (India) Private Ltd.
CHENNAI
Contractor
SHANDONG TIEJUN Electric Power Engineering Co.,Ltd
Contractor’s Engineer SHANDONG Electric Power Engineering Consulting
Institute CORP.,Ltd
Document Code:
文件编码
Rev. No .C
Date：Jan.2013
ITPCL CNT-1110233-EPC_9747-2172 28/01/2013
 Action - 1 Approved
 Action - 2 Approved except as noted on drawing. Revise
drawing and resubmit for records.
 Action - 3 Returned with Comments. Resubmit for approval.
 Action - 4 Not Approved. Resubmit for review
Action - 5 Information noted. Retained for reference
and records.
FI Letter Ref. No. Date:
Signature Initials: BR
This document has been reviewed as noted with regard to general
conformity with the Contract specifications and requirements. The
Vendor / Contractor is responsible for correctness of design calculation
and details. Approval of this document does not relieve the Vendor /
Contractor of his responsibility in carrying out the work correctly and
fulfilling the complete requirements of the contract nor does it limit the
purchasr's rights under the contract.
FICHTNER Consulting Engineers (India)
Private Limited, (FI) Chennai.
VENDOR DRAWING REVIEW STATUS


2. 0
CONTENT
1.0 SYSTEM FUNCTION & SCOPE OF DESIGN
2.0 GENERAL DESCRIPTION OF PULVERIZED COAL PREPARATION
SYSTEM
3.0 SYSTEM DESIGN CRITERIA
4.0 CONTROL PHILOSOPHY
5.0 ATTACHMENT LISTS

3. 1
1.0 SYSTEM FUNCTION & SCOPE OF DESIGN
1.1 Description of function
The function of the pulverized coal preparation system is:
Making use of mill to grind raw coal into pulverized coal as required for boiler
combustion.
1.2 Scope of design
Coal bunkers and coal bunker discharges to coal feeders inlet.
Coal feeders and coal feeder discharges to mills inlet.
Mills and pulverized coal pipes to burners.
Coal bunkers empty measures.
2.0 GENERAL DESCRIPTION OF PULVERIZED COAL
PREPARATION SYSTEM
2.1 System descriptions
Pulverized coal preparation system for this project is positive pressure cold
primary air fan direct system with a medium speed mill.
When operation, coal falls from coal bunker into coal feeder, and then makes
use of coal feeder feeding coal to mill. In the mill, Raw coal falls onto the
surfaces of two groups of grinding elements in relative motion via incoming
coal chute, and the coal is grinded into pulverized coal. The finished coal is
revolved together with the grinding elements, and thrown above the air vane
due to centrifugal pull and pushing action of the coal particles being ground
and to be ground. Hot air enters the circular drying space at a certain velocity
after passing the vane with deflection blades to dry and entrain the pulverized
coal into the separator in the top of the mill. The oversized coal particles are
precipitated and returned to the grinding zone for regrinding through the
bottom of the inversely conical separator. The finished coal is entrained out of
the mill by drying air via pulverized coal separator and discharged into
pulverized coal pipes. The primary air and pulverized coal mixture is blown into

4. 2
the boiler furnace for combustion through burners. The coal gangue and stone
that are hard to be ground are also thrown above the vane, but they can not be
entrained (due to air velocity is not enough for entraining them) and will fall to
the reject hopper through the vane.
There are four φ720x13 pulverized coal pipes with material of 10 carbon steel
and the ceramic lining bend (ceramic lining thickness value will be provided for
ITPCL/FI review after the ceramic lining bend vendor fixed) at every mill
separator outlet, each pipe corresponding to one burner of four corner at same
level, seven mills corresponding to seven level burners separately. This type of
arrangement can assure that the heat input equably when any mill out of
service. A pneumatic operated quick-acting gate is mounted on each
pulverized coal feed piping, witch can be shut down quickly. There is another
manual gate equipped at the inlet of the burner for further shut down. Due to
the different resistance of each pulverized coal pipe, every pipe is equipped
with an adjustable orifice union. This can adjust the resistance of each pipe to
enable every pipe resistance balance, and good for combustion regulating.
Every boiler is equipped with 7 raw coal bunkers, and each bunker
corresponding to a coal feeder. The geometry volume of each bunker is
999.05m3
. Each mill is equipped with a 100% capacity raw coal feeder, and the
feeder capacity is 5~101t/h. The output of the feeder can be regulated by
adjusting the revolution, and can be controlled manually or automatically
according to the boiler combustion need.
2.2 Arrangement feature
The bunker bay is located at front of boiler. The span of the bunker bay is
13.5m, and the column space for mill is 10m. There are EL. 46.2m, El. 17.0m
and El. 0.00m floors in the bunker bay. The coal belt conveyors are arranged
on the El. 46.2m floor. The El. 17.0m floor is operation floor, the coal feeders
are arranged on this floor. The steel raw coal bunkers are arranged in the
space between the El.46.2m and El.17.0m. On the EL. 0.00m floor, seven
medium speed mills and corresponding auxiliary equipments are arranged for
each boiler. One maintenance area will be provided for each boiler, the

5. 3
maintenance area is at the fixed (No 1 boiler) and extension (No 2 boiler) end
of the main power building and the column space is 10m. The sufficient hoist
for the maintenance of the motor and roller is arranged in bunker bay.
For the maintenance of the coal mills, one common double-beam motor driven
crane is provided for handling of the motor, roller, roller loading device of one
boiler. The max. maintenance weight is about 14.7t (roller), and the
maintenance height is about 11m. The mill lifting arrangement drawing refers
to 37-FA10871S-J0306-01.
2.3 Bunker emptying pipe
During the coal mill long time out of service, considering the high volatile
matter content, the coal bunker shall be empty. Two coal empty pipes are
provided for each bunker, one is near C row, the other is near D row. The
bunker empty pipe size is Φ530×10, material is Q235-A.
The coal empty pipe neat D row is connected from the bunker, and with one
manual guillotine damper the pipe goes to the vehicle passageway between D
row and H row, the coal can fall from bunker to truck from this pipe. And poking
holes are provided at slope pipe to prevent coal block.
The coal empty pipe near C row is provided for empty the coal in bunker
conical part. After empty the most coal in coal bunker by D row pipe, the
back-side door of coal feeder can be opened, combined with the reversal
rotation of the coal feeder, The coal falls from the hole reserved on the
operation floor and temporary coal chute to the ground floor, then the coal will
be carried out of the bunker bay by little truck.
The coal empty pipe arrangement refers to 37-FA10871S-J0601-01.
3.0 SYSTEM DESIGN CRITERIA
3.1 THE DESIGN OF THE MILL
There are 7 medium speed mills for each boiler, and each mill will serve the
burners in the four corners at the same elevation of the corner-fired boiler. The

6. 4
principle in selecting the mill is based on the contract: there are 7 mills for each
boiler, based upon degraded mills having 90％ of the rated capacity，when
grinding design coal, 100％BMCR could be achieved with 5 mills work and one
mill at operation standby, one mill at maintenance standby. When grinding
worst coal, 100％BMCR could be achieved with 6 mills work and one mill at
standby.
The main technical data of mill is shown as follows:
Type: Medium speed mill
Quantity for each boiler: 7
Number of the roller for each mill: 3
Power of the main motor of the mill (tentative): 950kW
Fineness of the pulverized coal (pass through 200
mesh):
70%
Actual capacity of single mill (BMCR): 64.56t/h（design coal）
60.12t/h（worst coal）
Guarantee capacity of single mill: 82.7t/h（design coal）
75.9t/h（worst coal）
Sealing air parameter 7.1t/h for each mill
Differential pressure
between sealing air
and hot primary air at
mill inlet: 2kPa
The calculation results of the 7 medium speed mills direct-firing pulverizing
system is shown in table 3.1-1.
Table 3.1-1 Calculation results of pulverizing system (one boiler BMCR
operating condition)
No. Item Sym Unit Design coal
Worst
coal
1 Coal consumption of the boiler Bg t/h 322.8 360.7
2 Grind ability index of the coal HGI 44 38
3
Moisture of as received basis of the
coal
Mar ％ 29 31
4 Fineness of the pulverized coal T200 ％ 30 30
5 Type of the mill Medium speed mills
6 Quantity of the mill Z set 7 7

7. 5
No. Item Sym Unit Design coal
Worst
coal
7 Actual capacity of the mill（BMCR） Bm t/h 64.56 60.12
8 Guarantee capacity of the mill Bm’ t/h 71.016 60.12
9 Outlet temperature of mill t ℃ 62 62
10
Hot air temperature （ primary,
secondary air, outlet of the air
preheater）
t ℃ 373/363 376/368
Medium speed mill pulverizing system refers to 37-FA10871S-J0201-11.
Mill lube oil system is used for gearbox, motor bearing and classifier bearing.
There is one set lube oil station for each mill, the lube oil station type is
OWTS11, and each station includes one oil tank with the capacity of 2800L,
two set of screw oil pumps with the flow of 250L/min and head of 0.6MPa(one
work, one standby), two set of lube oil coolers (one work, one standby) , one
set of duplex filter(screen aperture is 0.025mm)and the relevant fittings. The
close circulating water is used to cool the lube oil, the cooling water flow for
each lube oil station is 20m3
/h.
3.2 THE DESIGN OF COAL BUNKER AND FEEDER
Corresponding to the mill, there are the same numbers of raw coal bunkers for
each boiler as the mill. The geometry volume of each bunker is 1001.3m3
. The
coal bunkers are steel structure of cylindrical construction with conical bottom.
The calculation capacity of coal feeder is not less than 1.2 times of the
guarantee capacity of the mill.
The main technical data of coal bunker is shown as follows:
No. Item Unit Design coal / Worst coal
1 Number of bunkers for each boiler 个 7
2 Geometrical volume of one bunker m3
999.05
3
Calculated stockpile specific weight of
raw coal
t/m3 0.8
（EPC contract）

8. 6
No. Item Unit Design coal / Worst coal
4
Calculated coefficient of fullness of
raw coal bunker
0.85
（EPC contract）
5 Effective volume of each bunker m3
849.2
The main technical data of coal feeder is shown as follows:
No Item Unit Design coal/Worst coal
1 Type － F55
2 Explosion proof pressure MPa（g） 0.35
3 Capacity t/h 5～101
4
Distance between coal
feeder inlet and outlet
m 2.25
5 Power of the motor kW 4.0+0.75
6
Sealing air quantity to each
coal feeder
Nm3/min 7
6
Coal feeder outlet chute
size
mm 650×650×10/Φ660×10
7 Quantity for each boiler
Unit/boiler
台/炉
7
We take the following block prevention measures for bunker:
1）The outlet diameter of the bunker is 915mm.
2）The geometry of the raw coal bunkers and coal chutes to feeders and mills
could be designed to give mass flow of coal under all conditions particularly
when reclaiming wet coal from stock, avoid material holding up on the chute or
bunker sides or in any valley angles.
The angle between the wall and the horizontal is not less than 70°. The
bottom conical portion of coal bunker will be provided with stainless steel
liners.
There is air blast for each raw coal bunker to prevent coal jamming at the
conical part of the metal raw coal bunker.
3）Each mill is equipped with one belt gravimetric type belt coal feeder with
variable frequency motor, which could adjust the coal amount fed to boiler
according to the boiler load. The coal chutes at inlet and outlet of the mill are
made of stainless steel, so it is much convenient for the coal to flow, at the

9. 7
same time, it can be more wearable.
3.3 Explosion, dust, abrasion prevention design of the pulverizing system.
The explosion prevention design scope begins from the point 0.61m above the
inlet of the coal feeder and the pipes which connect to the mill and the interface
of the sealing air which connects to the system and it ends at the burner of the
boiler. The design explosion prevention pressure is 0.35MPa. The explosion
prevention measures of the direct-firing pulverizing system include the
following:
（1）The maximum permissible temperature at the outlet of the mill (or
separator) is 62℃.
（2）All the equipment and other component in the pulverizing system are
made of fire-resistance materials. Coal pipes between coal feeder and mill will
be stainless steel made.
（3）All the medium in the pulverizing system is designed to flow toward one
direction, that is to say, the medium is flow from the mill to the furnace, there is
no “U” type duct arrangement.
（4）There are motor driven gate on the coal chute of the inlet and outlet of the
coal feeder.
（5）A pneumatic operated quick-acting isolate damper and explosion vent is
mounted on the air duct at the inlet of the mill.
（6）
A pneumatic operated quick-acting damper is mounted on the outlet of the
mill (separator).That means there is a pneumatic operated quick-acting slide
plate damper is mounted on each pulverized coal feed piping of each mill, in
order to satisfy the requirement of explosion prevention and maintenance
isolation of the pulverizing system.
（7）
A manual operated isolate gate should be mounted on the pulverized coal
feed piping (close to the burner) between the mill and burner.
（8）The minimum velocity through the pulverized fuel lines at 50％BMCR
could not be less than 19 m/s. The coal-air mixture velocity through the PF
lines will not be less than 28 m/s at rated mill capacity.

10. 8
（9）There is a sealing coal column above the coal feeder.
（10）Pulverized coal feed piping should use welded connection to reduce the
number of flange.
（11）Equipment, ducts and components in this system are all air sealing and
dust sealing type to prevent accumulation of the dust.
（12）Mill fire extinguishing steam is supplied by auxiliary steam after
attemperator. The inerting steam parameter for each mill: flow 7~9t/h, pressure
0.4~0.6MPa, temperature 150~250 Deg.C.
3.4 Calculation results of the pulverizing system
一 Coal and pulverized coal Unit Design coal Worst coal
1 Raw coal size mm 25 25
2 Regularity coefficient of pulverized coal 1.0 1.0
3
Selected fineness of the pulverized coal
（pass through 200 mesh）
％ 70 70
4 Temperature of the raw coal ℃ 20 20
5 Hardgrove index 44 38
二 Characteristics of the mill
1 Type of the mill
Medium
speed mill
Medium
speed mill
2 Number of the mill set 7 7
3 Operating number of the mill m 5 6
4 Actual capacity（BMCR） t/h 64.56 60.12
6 Guarantee capacity t/h 82.7 75.9
三 Desiccant characteristics
1 Initial temperature of the desiccant ℃ 326 312
2 Initial dosage of the desiccant kg/kg 2.086 2.25
3 Percentage of the hot air in the desiccant 0.853 0.803
4 Percentage of the cold air in the desiccant 0.147 0.197
5
Desiccant temperature at the mill（separator）
outlet
℃ 62 62
6
Dew point temperature of the desiccant at
the mill outlet
℃ 54.2 53.5

11. 9
四 Air flow rate at some location
1
Mass flow rate of hot air piping at inlet of mill
（each mill）
kg/h 114880 108616.67
2
Mass flow rate of cold air piping at inlet of
mill（each mill）
kg/h 19820 26650
3
Flow rate of hot air piping at the inlet of mill
（each mill）
m3
/h 212773.91 202107.58
4
Flow rate of cold air piping at the inlet of mill
（each mill）
m3
/h 17900.1 24068.5
5
Flow rate of mixing air piping at inlet of mill
（each mill）
m3
/h 231332.07 226875.75
6
Flow rate at the outlet of mill （operation flow
rate）
m3
/h 154315.84 154042.54
五 Duct diameter at some location
1 Hot air duct at the inlet of mill（each mill） mm
2200×1500×
5
2200×1500×
5
2 Cold air duct at the inlet of mill（each mill） mm Ф820×5 Ф820×5
3 Mixing air duct at the inlet of mill（each mill） mm
2200×1500×
5
2200×1500×
5
4 Hot air duct in front of the boiler mm
2800×2600×
5
2800×2600×
5
5 Cold air duct in front of the boiler mm Ф1320×5 Ф1320×5
6 Pulverized coal piping mm Ф720×13 Ф720×13
7 Sealing air header duct mm Ф1020×5 Ф1020×5
六 Air and flue gas velocity
1 Hot air duct at the inlet of mill（each mill） m/s 18.11 17.21
2 Cold air duct at the inlet of mill（each mill） m/s 9.65 12.97
3 Mixing air duct at the inlet of mill（each mill） m/s 19.69 19.31
4 Hot air duct in front of the boiler m/s 22.44 23.3
5 Cold air duct in front of the boiler m/s 9.22 14.88
6 Pulverized coal piping m/s 28.34 28.29
7 Sealing air header duct m/s 11.11 13.34
3.5 REFERENCE CODE AND STANDARD
DL/T 5121-2000 Technical code for design of the thermal power plant air&
flue gas ducts/raw coal & pulverized coal piping
DL/T 5145-2002 Technical code for design and calculation of pulverized coal
preparation system of fossil-fired power plant

12. 10
DL/T 5203-2005 Technical code for explosion prevention design of coal and
pulverized coal preparation system of fossil fuel power
plant
D-LD2000 Design manual of the typical parts for air& flue gas ducts/
raw coal & pulverized coal piping
4 CONTROL PHILOSOPHY
4.1 control and interlock
4.1.1 Coal feeder
4.1.1.1 Start up
The necessary condition for starting up (coal feeder A starting up)
（a） Boiler is operation and the boiler combustion is stable with fuel oil
（b） Coal level of coal bunker A normal, and mill A operation
（c） No Coal feeder trip condition
（d） Sealing air gate for coal feeder A open
（e） Sealing air system for coal feeder A normal
（f） No coal block signal for coal feeder A
（g） Coal feeder A outlet gate open
When the above condition is OK, the coal feeder will be started as the
following sequence:
1. Open coal feeder seal air damper
2. Open coal feeder outlet gate
3. Start up coal feeder after the mill operation
4. Open coal feeder inlet gate
5. Adjust the coal feeder rotate speed as per required
4.1.1.2 Normal operation
During the normal operation, all the operating parameter will be controlled
by CCS.
Indicator in the control room
Coal feeder conveyor motor and cleaning motor status
Coal feeder inlet and out let gate status
Coal flow

13. 11
Coal feeder belt status
4.1.1.3 Alert
（a） Coal feeder A trip
（b） Main motor of coal feeder overload
（c） Coal belt deviation
（d） Coal block
（e） No coal on belt of coal feeder
（f） Cleaning Chain broken
（g） Temperature High of coal feeder
（h） Coal feeder frequency converter failure
（i） Coal feeder reverse running
4.1.1.4 Trip
When one of the below condition occur, the related coal feeder trip
（a） MFT
（b） Mill stopped
（c） When coal feeder operation, coal feeder outlet gate closed
（d） When coal feeder operation, the corresponding mill emergency trip
4.1.1.5 Normal shut down
（1） Coal feeder control changed to manual, and reduce the rotate
speed step by step to the minimum
（2） Stop the coal feeder
4.1.2 Mill
4.1.2.1 Start up
The necessary condition for mill starting up
（a） Coal system firing permission condition OK
（b） Coal layer firing energy permission OK
（c） Pneumatic-operated shutoff damper at mill outlet open
（d） Electric shutoff valve on fire extinguishing steam pipe to mill closed
（e） Difference Pressure between top and bottom of mill bowl not high
（f） Main motor bearing temperature normal
（g） Main motor stator winding temperature normal
（h） Gear box bearing temperature normal

14. 12
（i） Mixed primary air flow at mill inlet is ok
（j） Pneumatic-operated shutoff gate of hot primary air at mill inlet open
（k） Pneumatic-operated shutoff gate of cool primary air at mill inlet
open
（l） Motor-operated shutoff gate on seal air pipe open
（m） Any oil pump operation
（n） Lube oil system normal
（o） Mixture of air and pulverized coal temperature at mill outlet normal
（p） Any one seal air fan operation
（q） NO Mill TRIP Signal
（r） No flame detection amplifier of the corresponding layer coal burner
located #1~4 corner failure
When the above condition is OK, the mill will be started as the following
sequence:
（1） Start lube oil pump
（2） Open mill outlet shutoff gate
（3） Open sealing air damper
（4） Open shutoff gate at hot primary air duct and cold primary air duct
（5） Open the first reject gate and close the second reject gate
（6） Open the control damper at hot primary air duct and cold primary air
duct to warm mill
（7） Start dynamic classifier
（8） Start mill
4.1.2.2 Normal operation
During the normal operation, all the operating parameter will be controlled
by CCS.
Indicator in the control room
Mill status
Mill motor status
Gear box status
Mill and motor bearing temperature
Mill lubrication oil system status
Dynamic classifier status

15. 13
Dynamic classifier motor status
Mixed primary air flow
Pneumatic-operated shutoff gate status of hot primary air and cold primary
air at mill inlet
Pneumatic-operated shutoff damper at mill outlet status
The control damper at hot primary air duct and cold primary air duct status
The mill reject gate status
4.1.2.3 Alert
（a） Mill trip
（b） The lubricating oil temperature high
（c） The lubricating oil pressure low
（d） Lube oil tank level low
（e） Lube oil flow low
（f） Pressure difference between oil strainer inlet and outlet high
（g） Gear box bearing temperature high
（h） Pressure difference of mill grinding bowl high
（i） Mill motor stator winding temperature high
（j） Mill motor bearing temperature high
（k） Dynamic classifier bearing temperature
（l） Pulverized coal temperature high
（m） Oil pump trip
4.1.2.4 Trip
When one of the below condition occur, the related mill trip
（a） MFT
（b） All PA fan stop
（c） Both seal air fan stop
（d） Pressure of primary air at mill inlet low
（e） Mill inlet primary air flow low
（f） Pulverized coal temperature at mill outlet high
（g） Pressure difference between primary air and seal air at mill inlet low
（h） At least 3 coal burners lost flame when mill is running
（i） Main motor bearing temperature high
（j） Main motor stator winding temperature high

16. 14
（k） Bearing temperature of gear box high
（l） All oil pumps stopped.
（m） Lube oil pressure low
（n） Lube oil temperature high
（o） Lube oil tank level low
（p） Mill running & coal feeder not running, delay 5 minutes
（q） Pneumatic-operated shutoff damper of pulverized coal pipe at one
mill outlet closed
When Mills emergency trip happened, the following action will be
interlocked:
（a） Close Pneumatic-operated shutoff damper for hot primary air at mill
inlet
（b） Close Motor-operated shutoff damper at coal feeder inlet
（c） Stop the corresponding coal feeder
（d） Stop Mill
（e） Stop Dynamic classifier frequency-converter motor
（f） Close Pneumatic-operated shutoff damper for cool primary air at
mill inlet
（g） Close Pneumatic-operated shutoff damper of 4 pulverized coal pipe
at mill outlet
（h） Close Motor-operated shutoff damper in coal feeder outlet
（i） Close Motor-operated shutoff gate in seal air pipe of mill
4.1.2.5 Normal shut down
The necessary condition for mill shut down
（a） Any one oil pump operation
（b） Lube oil pressure not low
When the above condition is OK, the mill will be shut down as the following
sequence:
（1） Close Pneumatic-operated shutoff damper for cool primary air at
mill inlet
（2） Set coal feeder rotate speed in minimum
（3） Close Motor-operated shutoff damper at coal feeder inlet
（4） Stop Coal feeder

17. 15
（5） close Motor-operated shutoff damper at coal feeder outlet
（6） Stop Mill
（7） Close Pneumatic-operated shutoff damper for cool primary air at
mill inlet
（8） Close Pneumatic-operated shutoff damper of 4 pulverized coal pipe
at mill outlet
（9） Close Motor-operated shutoff gate in seal air pipe of mill
4.2 System operation description
4.2.1 Start up step
Inspect the mill, fan, APH, coal feeder and other coal preparation
equipments, all the equipments are ready to startup.
The boiler is ready to ignition, TG set is ready to startup, and the vacuum
condition has been built in condenser, the drain valve of superheater and
reheater is open.
(1) Start up APH
(2) Start up one ID fan, the start up one corresponding FD fan
(3) When the total air flow up to 30% of the rated load, start Furnace
purging
(4) Inspect ignition and fuel oil system, there is no leakage and ready to
start, then start MFT, and ignite igniter, start the fuel oil system
(5) Adjust secondary air damper
(6) After the furnace is preheated and the igniter flame is stable for
pulverized coal combustion, start the PA fan、coal mill and coal feeder
in turn
(7) Before start the coal burner, the burner igniter shall be start. When the
boiler load up to the setting value, the oil gun will be stopped one by
one according to the combustion condition in furnace
(8) Adjust secondary air flow to the requirement, the coal fuel flow and air
flow can be increased according to the loading. When the permission is
OK, the air flow adjustment can be put into auto control.
4.2.2 Abnormal operation
When the FD fan, ID fan, PA fan, APH, ESP or other equipment in the system
is failure, this condition is abnormal operation.

18. 16
When one set of any other equipment listed above is stopped, the unit will
operate at the maximum load as possible with the working equipment.
When one fan is failure, the load will be auto adjusted for one set fan operation.
But other equipment is failure, the load will be adjusted by manual.
When one ID fan is tripped, the corresponding FD fan will be interlocked
tripped. PA fan and the operating coal mill will be still operation, the unit will be
operation at the maximum load with one ID fan and one FD fan. The coal fuel
flow and PA flow will be reduced to the requirement of the load. The above
function is auto adjustment.
When one PA fan is tripped, the corresponding coal mill will be tripped, the unit
load will be reduced to the maximum load with one PA fan. The coal fuel flow
and air flow will be auto reduced to the requirement of the load.
When the motor of APH is failure, the standby motor will be auto startup, the
unit can be still in normal operation.
4.2.3 Normal operation
During normal operation, according to the requirement of boiler, turbine and all
equipment of the system, this system can be working at different conditions
under the control of auto control system.
The following item will be inspected during the normal operation:
(1) No air leakage and pulverized coal leakage, the anchor bolt of rotate
equipment is firm, bearing vibration is normal
(2) The coal level and temperature of coal bunker is normal
(3) Coal feed flow is stable, the local control panel has no alert signal
(4) No over heat on Coal feeder motor, the oil level of reducer is normal
(5) No belt deflection and broken of coal feeder
(6) Cleaning clapper of coal feeder normal
(7) The oil level of mill lube tank normal, the oil temperature normal
(8) Lube oil pump in normal operation, the pump outlet pressure and flow
normal, the filter pressure difference is normal, no oil leakage
(9) Cooling water for oil station is normal
(10) Mill reject is normal and without pulverized coal
(11) No abnormal vibration of dynamic classifier
(12) No abnormal vibration of mill
(13) The action of damper is agility

19. 17
(14) Mill motor is normal
4.2.4 Pulverized coal system stop
Manual stop
(1) During normal stop, the mill should be cooled till the temperature less than
the normal operation temperature, then clean the coal
(2) Reduce the coal feeder speed to the minimum gradually.
(3) Close the hot primary air control damper and hot PA guillotine gate when
the coal feeder speed is minimum, and the cold primary air damper should
be auto open at 100%
(4) Close the coal gate at coal feeder inlet, after there is no coal in coal feeder,
stop the coal feeder
(5) Purge the mill till the outlet temperature is less than the normal operation,
until the motor current is reduced to empty load current, stop the mill
(6) Stop dynamic classifier
(7) Close the cold primary air damper at mill inlet to 5% condition, and well
cool the mill, when the temperature at mill outlet is reduced to the ambient
temperature, close the mill outlet gate
(8) When the mill bearing temperature is reduced to the normal temperature,
stop the lube oil system
(9) Empty the mill reject
5.0 ATTACHMENT LISTS
5.1 Coal and ash analysis (as received basis)
1) Proximate Analysis (% by weight)
SI.No. Description
Performance
Coal For
Guarantee
Worst
Quality
Range for Design &
Performance Curves
1
Gross Calorific Value
（kcal/kg）
4600 4200 4200～5000
2 Ash 3.0 6.0 0.25～6
3 Volatile matter 38 35 32～41
4 Fixed carbon 30 28 27～32.75
5 Moisture 29 31 26～31

20. 18
6 Total 100 100
7 Grindability （HGI） 44 38 38～53
2) Ultimate Analysis Of Coal
SI.No. Description
Performance
Coal For
Guarantee
Worst
Quality
Range for
Design &
Performance
Curves
1 Carbon % 46.9 43.1
2 Hydrogen % 4.2 3.9
3 Oxygen % 15.6 14.9
4 Nitrogen % 1 0.9
5 Sulfur % 0.3 0.3 0.13～0.4
6 Ash % 3 6
7 Moisture % 29 31
8
Moisture of air dry based
%
20.8 25 20～25
3) Ash Analysis
1 Deformation Deg.C ≥1100
2 Hemisphere Deg.C / /
3 Flow Deg.C / /
4 Silica as SiO2 % 23.4 28.7 6～28.7
5 Alumina as Al2O3 % 22.6 21.66 3.02～27.2
6 Iron Oxide as Fe2O3 % 23.2 37 14.8～62.7
7 Titanium as TiO2 % 0.85 0.85 0.16～0.85
8 Phosphorus as P2O5 % 0.05 0.08 0.003～0.086
9 Potassium as K2O % 0.42 0.09** 0.07～0.42
10 Calcium as CaO % 11.2 4.24 4.24～31
11 Magnesium as MgO % 2.81 1.42 1.42～15.2

21. 19
12 Sodium as Na2O % 0.56 0.09** 0.09～0.56
13 Sulfite as SO3% 14.0 4.96 4.95～19.9
14 Manganese as Mn3O4 % 0.91 0.91 0.178～0.91
**
Na2O for design 0.09％ and range for correction curve 0.15% to 0.56%
K2O for design 0.09％ and range for correction curve 0.2% to 0.42%
5.2. Reference documents and drawings
37-FA10871S-J0201-11 BOILER PULVERIZING SYSTEM P&ID
37-FA10871S-J0306 LIFTING EQUIPMENT IN BOILER HOUSE
Coal mill sizing calculation
Coal feeder sizing calculation
Coal bunker sizing calculation