Question

Which value is determined by bringing all products of combustion back to original pre-combustion temperature?

(a) Higher calorific value

(b) Low calorific value

(c) Flash point value

(d) Fire point value

This question was posed to me in an online interview.

My enquiry is from Calorific Value of Fuels in chapter Steam Power Plant of Energy Engineering

Answer 1

Correct option is (a) Higher calorific value

Easiest explanation: High calorific value is determined, as all fuels contain hydrogen; they produce water vapor during combustion. When the products of combustion containing water vapor are cooled back to initial temperature, then all water vapors formed condense and evolve latent heat. This adds up to the heat liberated by burning the fuel, producing maximum amount of heat per kg of fuel. This heat is known as the higher calorific value of fuel, and it is denoted by HCV.