Question 88Steam Plants - QMED

The correct answer is C) Boiler steam flow. A two-element feed water regulator control system utilizes both the steam drum water level and the boiler steam flow as input signals. The steam flow provides a measure of the steam demand, which allows the control system to anticipate changes in water level and adjust the feed water flow accordingly. This helps maintain a stable water level in the steam drum, which is critical for safe and efficient boiler operation. The other options are incorrect because they do not represent the additional input signal required for a two-element feed water regulator control system. Boiler fuel flow, air flow, and feed flow are not the additional input signals used in this type of control system.