2. Description of EH Oil
• The main function of EH oil oil-supplying system is to provide HP
work oil for adjusting emergency system
• There are two EH oil pumps and two EH oil circulation pumps (Two
EHC pumps are pressure compensation variable plunger pump)
• if oil pressure drop to pressure compensation set value, pressure
compensator will adjust plunger stroke to increase system pressure
and flow rate
• There are two EH Circulation. (The main function of the two EH oil
circulation is: 1. cool EH oil, maintain EH oil work temperature; 2.
Filter and purify EH oil, remove moisture and debris in EH oil)
3. The main function of adjusting emergency system includes:
HP governor module, steam turbine latch and testing isolation module, emergency
governor and oil motor. Adjusting emergency system receives DEH order to fulfill latch,
valve-opening, rolling, tripping and over-speed protection, the main function of
adjusting emergency system are as the following.
1. latch
2. middle pressure cylinder startup
3. over-speed protection
4. quick-close steam-incoming valve
5. oil-spraying test
6. valve action test
Adjusting Emergency System
4. • Furnace Temperature
Range : 0 – 1300 Deg C
• Furnace Pressure
Range : 0 – 10000 mmWC
• Exhaust smoke temperature
Range : 0 – 300 Deg C
• Feed Water Pressure
Range : 0 – 25 Kg/cm2
• Feed Water Flow
Range : 0 – 52.2 TPH
• Steam Flow
Range : 0 – 45 TPH
• Flame Detector
Main Parameter
5. Main Parameter
• Drum level
Range : 0 – 350 mmWC
• Drum Pressure
Range : 0 – 25 Kg/cm2
6. PLC used to control & monitor
Make : Allen Bradley ( Redundancy control system )
Model : Logic – 5571
Version : 20.00
Scada : RS View32
7. Drum water level control.
Super Heater steam temperature control.
Boiler load control.
A) Stand by mode control.
B) Auto control.
Following Control loops used in the Boiler.
8. A) Auto control.
After the Burner1 & Burner2 have been successfully started under
auto mode, when the two burner stop burning because extreme high
pressure ( superheated steam pressure ), and the instant pressure
decrease to the setted value – 0.2 Mpa then both burners will restart
automatically.
B) Stand by mode control.
After the Burner1 and Burner2 have been successfully started under
auto mode when the instant pressure reaches 0.3 Mpa above the
setted value, the both burners will stop immediately.
Following Control loops used in the Boiler.
9. In the following cause, the interlock protection will happen and
the burner will stop.
Drum water level LL . ( 100 mmWC )
Inlet oil pressure low. ( 1.8 MPa )
Return oil pressure High. ( 0.5 MPa )
Burner Controller fault.
No signal in flame detector.
Air blower motor over load trip.
Interlock Protection
10. Drum water level measurement
• Water level signal can be measured by two type.
A) Electrical contact sensor Indication purpose.
B) DP type level transmitter for controlling purpose.
11. Combustion system:
A Complete set of combustion system is combined by burner, fan,
oil supply system, Air inlet system and control system.
Operating Instruction of combustion system:
Two no of burners run in synchronization. Each burner will has
one program controller and one flame detector. This system
performs the automatic ignition control by program controller. It
mainly include following parts.
A) Pre – sweeping.
Before the fuel enters into the furnace ( first time ignition or
after the Boiler trips ) a successful sweeping should be carried out
for furnace to eliminate any combustible fuel which is accumulate
in furnace, otherwise preventing the burner starting to protect
the system.
12. Combustion system
Flame detection:
Each burner has one flame detector for flame detection. When flame
is detected by detector. It will send signal to program controller. If signal
is not exact the program will alarm and cut all output.
Load adjustment ( Auto / Man)
After ignition procedure the system will enter into the normal
operation state. Control signal “Big fire” and “Small fire” step can also be
chosen. Burner will adjust the fuel and air quantity according to the fire
signal and realize load adjustment.
13. Combustion system
C) No MFT Instruction.
D) Finishing the furnace sweeping.
E) Fuel pressure is normal.
F) Combustion air pressure is in normal.
Ignition start order:
A) Starting the ignition transformer.
B) Open the fuel ignition valve.
C) Detect the flame by flame detector.
D) If the flame detection is in normal, the ignition is successful.
E) Opening the main fuel valve and oil nozzle.
F) Close the ignition valve after the main flame is ignited for three
second.
14. If ignition fails the alarm signal will appear on control cabinet,
then the operator shall confirm the alarm, then the close alarm.
The second ignition can only be started when the alarming has
been cancelled.
If ignition fails for 5 times then operator must not start the
burner again, the relevant inlet & return oil pressure need to be
checked. When the air blowers works for 30 minutes, then recheck
the Boiler water level, valves. When the precondition are met then
start the burner again.
15. Precondition before start up
• Step # 1
Before starting the Boiler, Start two Air blower to blow the
furnace. The follow up work can only continue after the Air
blowers normally run for 15 mins .
• Step # 2
When the two air blowers have run for 15 mins start the oil
pump, the oil pressure of main oil pipe for burner 1, burner 2
shall be kept between 2.0 MPa to 2.8 MPa on the oil way.
• Step # 3
Start one water pump when the drum water level reaches 200
to 230 mmwc.
16. Stop Procedure
• Step # 1
Stop the Boiler by pressing “Burner#1 – stop” “Burner#2 – stop”
to OR stop the both burner at the same time by pressing “ Full
stop”.
The “Emergency stop” can only be pressed in emergent.
• Step # 2
The 2 burner must be stopped for 15 mins before stopping the 2
air blowers. If there is only 1 burner running the 2 burners must be
at work.
17. Start up Procedure
• Step # 1
Start the boiler by pressing burner 1 & burner 2 on control cabinet OR
start two burners at the same time by pressing full start.
• Step # 2
Once the burner has been started the burner controller will run.
Open the control servo actuator to maximum fire location to blow the
furnace for 30 seconds. Close the servo actuator to open ignition
transformer. The ignition valve and main oil gun to form flame, ignition
has been okay, 5 seconds later turn the servo actuator to small fire
position the burner will perform load adjusting according to load.
18. Precautions
• In any case under the boiler need to be started, the operator shall
check the following matters.
A) Whether all the equipment in the control house are normal.
B) Whether control cable and power cable are normal.
C) Whether instruments OR boiler body are displaying right.
D) Whether all valve status are normal.
• As this Boiler fuel is light diesel, anytime when need to start the
boiler, the operator shall start the 2 air blower to blow the furnace
for 15 min, the air blowers can only be stopped after the boiler
have stopped for 15 mins.
• “ Emergency drain valve ” and “ Emergency stop ” buttons on the
control cabinet can not be pressed unless in emergency.
19. Main Equipment
• Air Blower Motor
A) Capacity – 75 KW ( 2 Nos )
• Feed Water Pump Motor
A) Capacity – 90 KW ( 2 Nos )
B) Rated flow – 55 m3/h
C) Rated delivery lift – 216 m.
20. Auxiliary Boiler Includes
1. Feed water system
2. De super Heating system
3. Steam system
The flow of feed water system is following:
Delivering the pressured water sucked from the water tank by
pump and preheated by economizer to the boiler steam drum.
Adjusting the drum level flow of feed water.
The flow of de super heating system is following:
Delivering the pressured water to de super heater steam.
Adjusting the flow of feed to de super heater according to outlet
temperature of super heated steam.
21. Auxiliary Boiler Includes
The flow of steam system is following :
Delivering the saturated steam in steam drum to boiler super
heater by steam connection tube, and then steam changes to
superheated steam after endotherm.
