What is the allowable percentage of economizer tubes that can be plugged without affecting boiler full power capability?

The allowable percentage of economizer tubes that can be plugged without affecting boiler full power capability is correctly identified as 20 percent. This percentage is crucial for maintaining efficient operation while minimizing the impact on performance. When economizer tubes are plugged, the flow of feedwater through those tubes is obstructed, which can lead to reduced heat transfer and efficiency.

By permitting up to 20 percent of the tubes to be plugged, the design ensures that the remaining tubes can handle the necessary flow and heat exchange required for the boiler to operate effectively at full power. Exceeding this percentage could compromise the steam output and efficiency by limiting the economizer's ability to preheat the feedwater adequately, leading to potential operational issues.

Understanding this limit is essential for Machinist Mates, as it informs maintenance decisions and operational protocols to ensure the longevity and reliability of boiler systems. Keeping a close account of the condition of economizer tubes helps in planning maintenance and ensuring optimal boiler performance.