CONTENTS
- Purpose of Oil system
- Equipment Details
- Diagrammatic Representation
- Local readings
- Permissives and Protections
- Oil Burner Sequence
Purpose of Fuel oil system
- During Cold start up for building up boiler parameters
- During Coal feeder choke
- During stopping and taking mill into service
- During hot and warm startups
General information
| Fuel oils types | Heavy fuel oil | Light fuel oil |
| Calorific value | 9000 kcal/kg | 10000 kcal/kg |
| Flash point | 100 deg | 66 deg |
| Viscosity | 100-150 cst | 2 cst |
| Spec. gravity | 0.88 | 0.83 |
Equipment Details
| Pump | HFO unload pump | HFO trans pump | LFO unloading pump | LFO trans pump |
| Pressure | 2.5 kg/cm2 | 30 kg/cm2 | 2.5 kg/cm2 | 20 kg/cm2 |
| Capacity | 25 m3/hr | 250 lpm | 25 m3/hr | 68 lpm |
| Motor rating | 7.5 kw /0.4kv | 26 kw /0.4kv | 5.5 kw/0.4KV | 5.5 kw/0.4KV |
| Current | 15 amps | 46 amps | 11 amps | 10.5 amps |
Diagrammatic Representation for LFO
Diagrammatic Representation for HFO
Local Readings
- LFO tank Level
- HFO tank level
- HFO header pressure
- HFO tank temperature
- HFO heater in service
Burner arrangement
Permissive for Fuel oil valves
LOTV (Light oil trip valve) opens when the following conditions are satisfied:-
1.NO MFT activated
2.LFO supply pressure adequate
3.Elevation AX1 all LO nozzle valves closed
4.LOTV trip conditions does not exist
HOTV( Heavy oil trip valve) opens when the following conditions are satisfied:-
i) NO MFT activated
ii) HO supply pressure adequate
iii) All HO nozzle valves closed
iv) HO supply temperature adequate
v) HO return trip valve open
vi) HO trip valve close command does not exist
Permissive for Fuel oil valves
HORV ( Heavy oil recirculation valve ) opens if the following conditions are satisfied:-
- HO return trip valve open push button pressed
- All HO nozzle valves are closed
Protections
HOTV ( Heavy oil trip valve) closes if any one of the following condition persist:-
- Pressure of HFO is very low (2.5 kg/cm2)
- Temperature of HFO is very low ( 90deg)
- Atomizing steam pressure very low (3.0 kg/cm2 & 2sec time delay), provided any one of the HONV is open
- MFT acts and HFO return trip valve not opens
- Loss of unit logic power supply
LOTV ( Light oil trip valve) closes if any one of the following condition persist:-
- LFO header pressure low ( 2.0kg/cm2)
- Atomizing air pressure very low (3.5 kg/cm2),provided any of LONV is open
- MFT active
- Loss of unit logic power supply
Oil Burner Sequence
On Start of any oil burner the following sequence will be followed:-
- Spark rod gives spark and igniter valve opens ( spark remains for 15 sec and igniter valve opens in 6 sec)
- If igniter flame proved then atomizing air/steam valve opens in (2-3) sec and then the oil valve will open in (2-3 sec)
- If scanner senses flame before 70 sec then the oil gun will be stabilized
- Igniter will be inside furnace for 70 sec from the instant of start command
On stop command of oil gun the following sequence will be followed:-
- Total time taken in shutdown sequence is 6.25 minutes
- Oil nozzle valve will be closed
- Atomizing nozzle valve will be closed
- Igniter comes into service
- If igniter flame is sensed , then scavenging and atomizing valve will be opened
- Igniter valve will be closed
Diagrammatic representation
LFO & HFO tank Details
LFO tank :
Nominal capacity : 397 kl
Stored capacity : 310 kl
Design liquid level : 6016 mm
HFO tank:
Nominal capacity : 1538 kl
Stored capacity : 1250 kl
Design liquid level : 8764 mm