Problems with boiler protection

1. After the boiler is shut down, and before the pressure in the drum drops to 0.5 MPa, connect the nitrogen filling system; the diameter of the nitrogen supply pipes should generally be no less than 20 mm, and the nitrogen filling system can be connected via the air pipes of the high-temperature superheater； 2. When the drum pressure drops to 0.5 MPa, nitrogen begins to be introduced into the boiler. While maintaining a nitrogen pressure of 0.5 MPa, drain the water by using this pressure; once all the water in the furnace has been removed via nitrogen pressure, close all the drainage valves, or start filling with nitrogen after the residual heat has been removed ； 3. Conduct a thorough inspection of the boiler’s steam and water systems; tightly close all air valves, drain valves, sewage valves, as well as the feedwater and main steam pipes along with their drain valves, to ensure that the entire nitrogen filling system is airtight ； 4. Use the outlet control valve of the nitrogen tank to adjust the pressure to around 0.3 MPa; when the pressure inside the vessel falls below this value, nitrogen is automatically supplied into the vessel ； 5. During nitrogen purging maintenance, the nitrogen pressure inside the vessel should be maintained at 0.03–0.05 MPa (gauge pressure), with a nitrogen purity of over 98%; meanwhile, the operators must record the nitrogen pressure twice per shift.