Boiler performance metrics Which of the following quantities are used to measure and report the performance of a steam boiler in routine practice?

Introduction / Context:
Boiler performance is expressed using standardized metrics so engineers can compare different units and verify contractual guarantees. Common measures include evaporation rate, mass flow of steam per hour, and specific evaporation (kg of steam per kg of fuel), which collectively capture capacity and efficiency.

Given Data / Assumptions:

• Steady boiler operation at a specified pressure and quality (saturated or superheated).
• Fuel characteristics and feedwater conditions are known for fair comparison.
• Accurate measurements of feedwater, steam, and fuel flows are available.

Concept / Approach:
Three complementary indicators are used: capacity (total steam per hour), equivalent or actual evaporation rate (water evaporated per hour, often corrected to standard conditions), and efficiency-related ratios like kg of steam per kg of fuel. Together they describe how much steam is made, how fast it is produced, and how effectively fuel energy is converted into steam energy.

Step-by-Step Solution:
Define capacity: Steam production rate, typically kg/h or t/h, indicates sizing and load.Define evaporation rate: Mass of water converted to steam per hour; may be reported as equivalent evaporation from and at 100°C for comparisons.Define specific evaporation: kg steam per kg fuel, linking output to fuel input and relating to boiler efficiency.Recognize that all three are standard and jointly reflect boiler performance.

Verification / Alternative check:
Boiler trial codes and acceptance tests tabulate evaporation, equivalent evaporation, and efficiency or heat balance—matching options (a), (b), and (c). Therefore, “all of these” is the correct comprehensive choice.

Why Other Options Are Wrong:
Choosing only one ignores other equally valid and customary metrics. “None of these” conflicts with industry practice and testing standards.

Common Pitfalls:
Comparing boilers using raw evaporation without correcting for feedwater temperature; overlooking that kg/kg fuel depends on fuel calorific value and operating pressure/quality.

Final Answer:
all of these