Boiler performance terminology — choose the correct definition of equivalent evaporation: Which option best defines “equivalent evaporation” used for comparing boilers of different operating conditions?

Introduction:
Because boilers operate at different pressures and feedwater temperatures, engineers normalize performance to a common reference called “equivalent evaporation.” This allows fair comparison of capacities and efficiencies across diverse conditions.

Given Data / Assumptions:

• Reference state: “from and at 100°C.”
• Dry saturated steam as the reference output.
• Steady operation; standard definitions from boiler engineering.

Concept / Approach:
Equivalent evaporation expresses the mass of water that would be evaporated per unit time at the reference condition if the same heat input were applied. It is a conversion of the actual evaporation at operating conditions to the standardized basis “from and at 100°C.” This is not an efficiency or a fixed constant; it is a normalized mass flow measure.

Step-by-Step Solution:

Verification / Alternative check:
Handbooks show conversions using enthalpy differences: m_eq = (Q_actual) / (h_g,100 − h_f,100). This matches the verbal definition.

Why Other Options Are Wrong:

• Option a: that is boiler efficiency (heat used/heat released).
• Option b: that is “steam generation per kg of fuel,” not the standardized reference.
• Option d: 15.653 kg/h corresponds to 1 boiler horsepower, not a definition of equivalent evaporation.
• Option e: unrelated ratio; no standard meaning.

Common Pitfalls:
Confusing equivalent evaporation with efficiency or boiler horsepower; forgetting the “dry saturated at 100°C” reference.

Final Answer: