During cold starting of boiler, the whole process of pressurizing is controlled in 4 to 6 hours. The boiler shall be pressurized slowly and smoothly in even speed. 

Operation of pressurizing: 

1. With the ignition process, the steam pressure rises continuously, when the pressure of boiler drum rises to 0.1-0.2 Mpa, close the air door, close the header for the lower-temperature superheater and level-1 desuperheater header and lower header under each enclosure wall and the draining valve of the circular lower header, flush the local water level gauge and calibrate the indication of the water level gauge to confirm it is normal. 

2. When the steam drum pressure rises to 0.2-0.3 Mpa, open the air bleeding valve by 20% of openness, inform the thermal engineering person and the chemical water treatment person to flush the instrument conduit and chemical sampling tube. 

3. When the steam drum pressure rises to 0.3-0.5 MPa, inform the maintenance person to hot tight the flange bolts, record the expansion indicating valve once and blow down the lower header of the water-cooling wall on a regular basis. 

4. Adjust the air bleeding valve, maintain the steam temperature at outlet of superheater to exceed the saturated temperature  by 15 ℃ at least, and to make the steam exhausting quantity be greater than 10%. Cool the superheater and keep the  temperature difference of upper wall and lower wall to be less than 50 ℃. 

5. When the steam drum pressure rises to 1.0 Mpa, open the primary valve and the secondary valve for back flushing and the water draining valve of the attemperation water platform in order to empty the accumulated water inside the attemperation water pipe. 

6. When the steam drum pressure rises to 3.0 Mpa, record the expansion indicating value once and blow down the lower header of water cooling wall for second time. 

7. When the drum pressure rises to 6.0 Mpa, stabilize the pressure, completely check the boiler unit, if the abnormal is found, the drum pressurizing shall be stopped and it can be continued after the faults have been eliminated. 

8. When the steam drum pressure rises to 8.0 Mpa, notify the chemical water treatment persons to test the steam quality; Wash the water level gauge, calibrate the steam drum water level and pressure and record the expansion indicating value again. 

9. When the pressure rises to 9.0 Mpa, contact the shift chief operator, the operator for steam turbine and the adjacent boiler for preparing combining the boiler. If you want to calibrate the emergency exit, then the preparation of calibrating the emergency exit shall be done and the equipment shall be completely checked. Record the expansion indicating value again.