How to operate a boiler?
The operating procedure of a boiler depends on the type and the manufacturer’s instruction. Yet, there are few common points that should be kept in mind while operating any type of boiler on board a ship. So lets get down to some basic boiler operation training and the general procedures for operating a boiler are as follows.
Before starting the boiler
The following things should be checked thoroughly before starting the boiler:
- All the up-takes for the exhaust gases should be checked properly for a clear flow and to prevent any kind of obstacle or diversion.All the dampers should be checked for open position. All the vents should also be kept open.
- All feed water connections, combustion air connections and pressure gauges should be opened or checked for proper working condition
- Alarms should be checked for sound and proper working condition
- The connections to the super heater and those in between the super heaters should be opened fully to prevent any kind of disturbance in the steam flow.
- All the boiler water drains and blow-down cocks should be properly closed.
- The boiler should only be filled with De-aerated water till slightly below the working level
- All the header vents should be closed to prevent water leakage
- Water level in the economizer should be checked and the vents should be shut off after blowing out any trapped air.
- Forced draft fans should be checked for speed and sound. In case exhaust gas air heaters are provided, the connections to the forced draft fans should be diverted.
- Fuel oil system should be checked for any closed valves and the fuel oil should be adequately heated before circulation to prevent any kind of pipe blockage.
- Firstly, the forced draft fans should be started to purge the system to remove any trapped exhaust gases or oil vapours.
- All the air slides at different registers should be checked and closed, except the "lightning up" burner.
- Th operating burner should then be lit for low firing rate and efficient combustion
- The fuel oil flow should be matched with the speed of the fan to ensure a complete combustion with steady flame.
- Once the boiler starts and steam starts coming out of the superheater vents, the superheater header vents should be closed.
- As soon as the pressure reaches 210 kpa, the air drum vents should be closed.
- The working pressure should be brought up gradually to avoid overheating and damage to refractory material .
- After the main and auxiliary lines are warmed through, the drains should be closed.
- All the water level gauges should also be blown through and checked to ensure correct reading.
- The safety valves should be lifted and released when the pressure is 3 bar below the normal operating value.
- Once the operating pressure is reached , the boiler should be put on load and the superheater circulatory valves should be closed.
- All the vents, drains and by passes should also be closed.
- The water level in the boiler should be properly checked and the cascade system should be monitored for correct operation.