Tuesday, January 3, 2012

Boiler operation from cold start

Boiler operation from cold start

Preoperational precautions

1. Make sure all maintenance services are finished
2. Make sure all air gates and flue gases gates are closed
3. Make sure no personal are working on site
4. Make sure all electric devices have power
5. Air compressors must be working
6. All air pressures in the system must be at normal
7. Cooling water system must be ready
8. Secondary Steam system must be on
9. Drum must be filled with water

Turning Feed Pump on :

1. Water tank level at normal (0) level
2. Lubricating oil pressure < 1.4 bar
3. Gear box at neutral position
4. Valve for controlling lowest rate of feed water must be open
5. Suction valve must be open
6. Delivery Valve and bypass must be closed.
7. Cooling water valve must be open

Steps :

1. The bypass valve for the delivery pipe is opened
2. The delivery valve is opened
3. The control valve is opened for starting operation
4. The entrance valve to the economizer is opened

The operating range for rate of feed water should be about (200-250 ton/hr)

5. After the drum is filled with water the delivery valve to the drum is closed to start operation
6. The ammonia (NH3) pump is turned on to increase the water PH
7. Hydrazine (N2H4) is used to remove Oxygen(O2) and increase PH
8. Sodium Phosphate (NA3PO4) is used to remove dissolved salts

Turning the air system and flue gas system on :

Precautions before operating
a) Air pressure must be 8 bar
b) Cooling water system must be normal point
c) Inlet and outlet gates for the air must be closed
d) Inlet and outlet gates for the flue gases must be closed

Air preheaters are to be turned on now
a) Open the inlet and outlet gates for the flue gases
b) Open the inlet and outlet gates for the air
c) The forced air fan is to be turned on now
d) After 15 sec the induced fan is to be turned on.

Turning the Fans on :

Precautions for turning fans on:
1. Air Preheater must be turned on
2. Cooling water system must be operational
3. Air suction gates must be closed on both sides
4. Air delivery gates must be closed on both sides
5. Lubricating oil pump must be operational
6. Hydraulic coupling must be at normal (0) level

Turning air Fans on procedure:
1. Turn the fan on
2. Hydraulic coupling is to be opened 20 %
3. The delivery gate for the fan is to be opened
4. The suction gate for the fan is to be opened
The hydraulic coupling and the fan air suction gates must be set to AUTO setting
All gates must be put to AUTO setting as follows:
Over fire Damper 20 % open
Aux. Dampers 40 % open
Fuel Air Damper 60%


Turning the flue gas fan and flame detector on:
1. Air fans must be turned on
2. Outlet gates for air must be open
3. Circulating Flue gases fans are to be turned on now

Operating Precautions :

1. Air fans must be on
2. Cooling water system must be operational
3. Inlet and outlet flue gases gates must be closed
4. Heater gates must be opened
5. Lubricating oil pump must be on

Secondary steam system must be turned on
Secondary steam must be at 360 C at about 13.5 bar
Secondary steam destinations:
1. Air heaters
2. Gas absorbers
3. Air dumpers
4. steam atomizer burners
5. Secondary steam for steam turbines

Fuel System :

1. Fuel level must be normal
2. Leakage preventing pump must be operational
3. suction valve must be opened
4. control valve for the lowest level of fuel must be opened
5. the delivery valve must be opened
The main fuel pump can now be turned on
Minimum pressure for the fuel is 20 bar by adjusting the control valve
The steam atomizing system is now to be turned on

After checking that the steam level is normal the inlet valve for the secondary steam is to be opened
The atomizing steam pressure is to be 11 bar

Purging condition
1. Air flow not much than 30%
2. One or more FDF running
3. Fuel Oil trip valve closed
4. Fuel gas trip valve closed
5. All igniter off
6. All scanner no flame.
7. MFT
8. Igniter gas oil supply pressure must be proper
9. Fuel oil or gas supply pressure must be proper
10. All flue gases and air damper are to be opened
11. All burners valve must be closed
12. BCS power supply normal
13. All Aux. Damper modulating

Boiler Storage
As soon as possible after the end of the heating season, take these steps, where applicable:
1. Remove all fuses from the burner circuit.
2. Remove soot and ash from the furnace, tubes, and flue surfaces.
3. Remove all fly ash from stack cleanout.
4. Drain the broiler completely after letting the water cool.
5. Flush the boiler to remove all sludge, and loose scale particles.
6. See that defective tubes, nipples, stay bolts, packings, and insulation are repaired or replaced as required.
7. Clean and overhaul all boiler accessories such as safety valves, gauge glasses, and firing equipment. Special attention should be given to low-water cutoffs and feedwater regulators to ascertain that float (or electrode) chambers and connections are free of deposits.
8. Check the condensate return system for tightness of components.











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