Question

Which one of the following has the highest calorific value?

(A) Kerosene

(B) Biogas

(C) LPG

(D) Petrol

Answer 1

So, in this question for finding the highest calorific value we have to see how much energy they release when 1kg of fuel or any other substance is used.

Step by step solution:

We know that calorific value is the amount of energy released or produced by 1 kg of fuel burned (at normal conditions or any other substance is burnt in the presence of oxygen. Its SI unit is kJ/kg.

Higher calorific value means (gross calorific value-GCV) the total quantity of heat liberated from combustion of unit mass or unit volume of given fuel when by products/side products are allowed to cool at room temperature.

Calorific value, measured in British thermal units or megajoules per kilogram, is the amount of chemical energy stored in a coal that is released as thermal energy upon combustion.

Lower calorific value means the total quantity of heat liberated from combustion of unit mass or unit volume of given fuel when side products are allowed to escape. So, for this question data of calorific values are:

-For kerosene LCV is 43.1 MJ/kg and HCV is 46.2 MJ/kg.

-For Biogas it is 19-25 MJ/m3. And it depends on the percentage of methane.

-For LPG it is 46.1 MJ/kg.

-For petrol it is 45.8 MJ/kg.

From the above explanation we can say that LPG has the highest calorific value.

So, the correct answer is option (C).

Note: The combustion of a fuel product generates water vapor. Certain techniques are used to recover the quantity of heat contained in this water vapor by condensing it.