Boiler performance terminology: “The amount of water evaporated (steam produced) in kilograms per kilogram of fuel burned is termed the evaporative capacity of a boiler.” Evaluate the correctness of this statement.

Introduction / Context:
Boiler literature distinguishes between several metrics: capacity (or power), evaporation ratio, equivalent evaporation, and efficiency. Mixing these terms leads to misinterpretation of performance data. This item checks recognition of the correct definition for “kg steam per kg fuel”.

Given Data / Assumptions:

• Steam generation is steady.
• Fuel mass flow is measured accurately.
• Standard definitions from boiler practice apply.

Concept / Approach:
The quantity “kg of steam produced per kg of fuel” is the evaporation ratio, not the evaporative capacity. Evaporative capacity (or boiler capacity) usually refers to the rate of steam generation (e.g., kg/h, t/h) at specified pressure and temperature. Equivalent evaporation further normalizes steam production to “from and at 100°C” for comparison across conditions.

Step-by-Step Solution:
Write the definition: evaporation ratio ER = m_steam / m_fuel (dimensionless).Define capacity: capacity = dm_steam/dt (e.g., kg/h) at rated conditions.Compare: the statement uses a fuel-normalized, dimensionless number yet calls it “capacity”, which should be a rate with units.Conclude: the statement is incorrect; it describes evaporation ratio, not evaporative capacity.

Verification / Alternative check:
Manufacturer datasheets list capacity separately from ER; ER improves with heat-recovery devices but the rated capacity name remains a flow rate.

Why Other Options Are Wrong:
Agree/conditional Agree: they perpetuate the incorrect definition.

“Disagree; it defines boiler efficiency”: ER correlates with efficiency but is not the efficiency itself.

Common Pitfalls:
Calling ER “power” or “capacity”; ignoring that capacity has time units while ER does not.

Final Answer:
Disagree