Comparing manufactured gases – highest calorific value Among the following manufactured/industrial fuel gases, which typically has the highest calorific value per unit volume at standard conditions?

Introduction / Context:
Manufactured gases differ widely in composition (H2, CO, CH4, N2, CO2) and therefore in calorific value (CV). Knowing their relative CV is important for burner design, engine suitability, and pipeline distribution planning.

Given Data / Assumptions:

• Typical compositions without enrichment.
• Standard temperature and pressure for volumetric CV comparison.
• Historical industry definitions of coal gas, producer gas, Mond gas, and blast furnace gas.

Concept / Approach:

Coal gas (town gas) produced from coal carbonization contains a significant fraction of hydrogen, methane, and light hydrocarbons, leading to a relatively high CV. Producer gas and Mond gas are nitrogen-diluted (air used in gasification), with lower CV. Blast furnace gas contains substantial CO2 and N2 with modest CO, yielding the lowest CV among those listed. Hence, coal gas ranks highest on a volumetric basis among the options provided.

Step-by-Step Solution:

Verification / Alternative check:

Representative CV (approximate, MJ/Nm^3): coal gas ~ 18–20; producer gas ~ 4–6; Mond gas ~ 5–7; blast furnace gas ~ 3–4. Rankings confirm the choice.

Why Other Options Are Wrong:

Producer/Mond/BFG have substantial nitrogen or carbon dioxide dilution, lowering CV.Coke oven gas can be high CV but is not among the original set in the source list; the comparative context here points to coal gas as the typical highest CV versus producer/Mond/BFG.

Common Pitfalls:

Confusing coal gas with natural gas; natural gas (mostly methane) has even higher CV, but it is not a manufactured gas in this context.

Final Answer:

Coal gas