If a boiler is generating 20,000 lb/hr of steam, how much feedwater must be supplied?

The correct answer is based on the principle of conservation of mass and the efficiency of the steam generation process. When a boiler generates steam, it converts feedwater into steam; however, not all feedwater is converted into steam due to the efficiency of the system and potential losses, such as radiation or blowdown losses.

In an ideal situation with 100% efficiency, the amount of feedwater needed to produce a given amount of steam would be equal to the steam produced. Therefore, if a boiler is generating 20,000 lb/hr of steam under optimal conditions, it would logically require 20,000 lb/hr of feedwater.

In real-world applications, factors such as the temperature of the feedwater, operating pressure, and the heat transfer efficiency of the boiler can affect the exact amount of feedwater required. However, in many scenarios or simplified calculations, it's acceptable to use the same figure for the feedwater supply as the steam generation output in situations where detailed efficiency calculations are not provided.