Fuels

Question 1

What is fuel?

Answer 1

Fuel is any substance which is obtained in bulk and on combustion will produce energy in the form of heat.
It can be used for industrial purposes as well as domestic use.

Question 2

What is calorific value?

Answer 2

The total quantity of heat liberated when a unit mass or a unit volume is made to undergo complete combustion in air or oxygen is called its calorific value.

Question 3

Gross calorific value (GCV) or high calorific value (HCV)

Answer 3

The total quantity of heat produced when a unit mass or unit volume of a fuel is completely burned and the products are allowed to cool to room temperature.

Question 4

Lower calorific value (LCV) or Net calorific value (NCV).

Answer 4

Total quantity of heat produced when unit quantity of fuel is burnt completely and the products are allowed to escape.
LCV=∆1
LCV=HCV→ latent heat of vaporisation

Question 5

Define octane number.

Answer 5

Octane number is a major of a fuels resistance to knocking in internal combustion engines. It indicates the fuel’s ability to withstand compression before ignitions spontaneously.
higher octane number equals greater resistance to knocking, making the fuel suitable for use in high performance engines.

Question 6

Define ceatane number.

Answer 6

The seaten number is the major of ignition quality of diesel fuel.
Higher cetane number equals better ignition quality i.e smoother combustion

Question 7

Explain how the mining of petroleum is carried out with the help of a neat labelled diagram.

Answer 7

——–DIAGRAM———

Three conditions that must be satisfied for the accumulation of workable quantities of petroleum.
1) A porous rock should be present which acts as a reservoir.
2) A cap rock overlying the reservoir rock to prevent the escape of oil upwards.
3) A closer to prevent the lateral migration.
- The crude oil is found deep below the earth’s crust. In order to bring oil to the surface, holes are drilled into the earth’s crust and pipes are sunk deep to the oil bearing rocks. Initially the crude oil rushes out to the surface because of the pressure exerted by the natural gas. Later as the pressure becomes low the crude oil is mechanically pumped up using lift pumps.