Fuel testing instruments – application of Junker's calorimeter In industrial fuel testing, the Junker's gas calorimeter is specifically used to determine the calorific (heating) value of which class of fuels?

Introduction / Context:
The calorific value (CV) of a fuel is the amount of heat released during complete combustion. Different calorimeters are optimized for different fuel phases. The Junker's calorimeter is a classic continuous-flow instrument widely used in gas plants, utilities, and laboratories to measure the heating value of town gas, natural gas, and other gaseous mixtures accurately.

Given Data / Assumptions:

• Fuel phase to be tested can be solid, liquid, or gas.
• Objective is to measure higher or lower heating value under steady conditions.
• Junker's design employs a burner and a gas–to–water heat exchanger with controlled flow rates.

Concept / Approach:
In a Junker's calorimeter, the test gas burns at a standardized burner. The combustion products transfer heat to a measured flow of cooling water in a counter-current exchanger. Knowing inlet/outlet water temperatures, water flow rate, and gas flow rate allows calculation of the gas CV from an energy balance: heat gained by water equals heat released by fuel minus sensible and latent corrections where applicable.

Step-by-Step Solution:

Verification / Alternative check:
Solid and liquid fuels are typically measured using bomb calorimeters (constant-volume) or oil calorimeters; gaseous fuels use Junker's, Boy's, or Parr gas calorimeters.

Why Other Options Are Wrong:

• Pulverised coal: Measured via bomb calorimetry under constant volume with oxygen.
• Fuel oil: Determined using liquid-fuel (e.g., bomb) calorimeters or combustion-type oil calorimeters.
• None of these: Incorrect because the instrument is explicitly for gases.

Common Pitfalls:
Confusing lower vs. higher heating value; gas calorimeters may require condensation correction if water vapor is condensed or not.

Final Answer:
gaseous fuels