Coal testing: Ultimate analysis of coal determines the percentage of which constituents?

Introduction / Context:
Coal characterization uses proximate and ultimate analyses. Ultimate analysis provides elemental composition essential for combustion calculations, emission estimates, and boiler design (air requirement, flue-gas composition, SOx/NOx potential).

Given Data / Assumptions:

• Standard ultimate analysis reports mass percentages of C, H, N, S, O, and ash.
• Moisture may be reported separately or included depending on reporting basis.
• Laboratory procedures follow standardized methods (e.g., ASTM).

Concept / Approach:

Ultimate analysis breaks coal into elements: carbon, hydrogen, nitrogen, sulphur, oxygen (by difference), and ash. Therefore, options naming carbon; hydrogen and nitrogen; and sulphur and ash are each part of ultimate analysis. The combined option “all of these” is correct.

Step-by-Step Solution:

Verification / Alternative check:

Engineering manuals and standards confirm the same constituent list for ultimate analysis used in boiler and environmental calculations.

Why Other Options Are Wrong:

Any single subset alone is incomplete; moisture alone is proximate analysis content, not the full ultimate analysis.

Common Pitfalls:

Confusing proximate (moisture, volatile matter, fixed carbon, ash) with ultimate (elemental) analysis.

Final Answer:

all of these