Inflatable maintenance is suitable for boilers that have been shut down for how long?

During the shutdown of the steam generator, there are three maintenance methods:

1. Pressure maintenance
When the gas boiler is shut down for less than a week, pressure maintenance can be used. That is, before the shutdown process is terminated, the steam-water system is filled with water, the residual pressure is maintained at (0.05~0.1) MPa, and the pot water temperature is maintained above 100°C. This can prevent air from entering the gas boiler. Measures to maintain the pressure and temperature inside the gas boiler are: heating by steam from an adjacent furnace, or regular heating by the furnace.

2. Wet maintenance
When the gas boiler is out of service for less than one month, wet maintenance can be used. Wet maintenance is to fill the gas boiler steam and water system with soft water containing alkali solution, leaving no steam space. Because an aqueous solution with appropriate alkalinity can form a stable oxide film on the metal surface, thereby preventing corrosion from continuing. During the wet maintenance process, a low-fire oven should be used regularly to keep the outside of the heating surface dry. Turn on the pump regularly to circulate the water. Check the alkalinity of the water regularly. If the alkalinity decreases, add alkaline solution appropriately.

3. Dry maintenance
When the gas boiler is out of service for a long time, dry maintenance can be used. Dry maintenance refers to the method of placing desiccant in the pot and furnace for protection. The specific method is: after stopping the boiler, drain the pot water, use the residual temperature of the furnace to dry the gas boiler, remove the scale in the pot in time, then put the tray containing the desiccant into the drum and on the grate, close all Valves and manholes and handhole doors. Check the maintenance status regularly and replace expired desiccant in time.

4. Inflatable maintenance
Inflatable maintenance can be used for long-term furnace shutdown maintenance. After the gas boiler is shut down, do not release water to keep the water level at the high water level, take measures to deoxidize the gas boiler, and then isolate the boiler water from the outside world. Pour in nitrogen or ammonia to maintain the pressure after inflation at (0.2~0.3) MPa. Since nitrogen can react with oxygen to form nitrogen oxide, oxygen cannot come into contact with the steel plate. When ammonia is dissolved in water, it makes the water alkaline and can effectively prevent oxygen corrosion. Therefore, both nitrogen and ammonia are good preservatives. Inflatable maintenance effect is good, and its maintenance requires good tightness of the gas boiler steam and water system.