Home > Operational Area > BOILER
Handling of Loss of ignition Accidents of Coke-dropping from Boiler

1. When the boiler is extinguished, FSSS protection device and MFT both shall act to automatically stop the boiler, otherwise MFT shall be manually operated to stop the boiler .
2. It is required to immediately close the manually operated valve for attemperating water, to shift to the auxiliary power, to open the drainage valve at the steam turbine and close the main control valve to 5MW load approximately.
3. It is forbidden to quit the protection and to apply the methods of closing small air valve and filling oil to the coal for deflagration in order to resume combustion. Air shall be supplied continuously in order to reduce the temperature of bed.
4. The boiler drum water level is automatically changed to manually operation.
5. Resume the alarm signals on OS frame, close the control valve and baffle of the primary fan and regulate the air volume of the forced-draught blower to the purging rate to meet the purging condition. After the purging is qualified, the ignition shall be resumed quickly and low steam temperature protective device shall be avoided to act.
6. Two primary fans shall be started.
7. The pre-heated steam shall be supplied for purging the soot.      
8. If the coke drops and the water cooled wall is damaged, the water supply cannot maintain the boiler drum water level, the steam turbine shall be stopped for handling.
9. When there are about 6 oil guns, start the first mill, gradually open the control valve to increase the load and open the manually operated valve for attemperation water valve, roughly control the first level attemperation water to be supplied automatically, and fine adjust the second-level water spraying. After the first mill capacity reaches to over 60%, the bed will be slowly stable, and at this moment slightly reduce the air supply, turn on the second mill until about 50% capacity of milling, reduce 3 to 4 oil guns to maintain the load to 200MW. If the steam temperature is stable, gradually withdraw the oil guns and pay attention to combustion.
10. The reheater shall be strictly prevented from overheating. In case there is rising tendency of temperature, it is required to open the attemperation water and make the temperature slowly rise, During the whole process of starting, the flue gas baffle shall be used for coordinating the adjustment . If the temperature rises quickly, the numbers of oil guns or air supply may be reduced.
11. Water level shall be controlled frequently and fine, it is possible not to switch the main water supply valve and it is also possible to adjust the water level with one steam pump, but the water level shall not be regulated by a large margin to prevent large amount of attemperatin water from affecting the temperature.
12.  After the load reaches to 200MW, it is required to withdraw the oil guns, shift to auxiliary power, turn on the electrostatic precipitator to desulfurize in order to maintain the parameters to be in normal range.
13. The equipment of boiler side shall be completely inspected once, and soot-blowing to the proper of the boiler shall be carried once completely.

Favourite