CALORIFIC VALUE OF

KEROSENE!!!

USING BOMB CALORIMETER

CALORIFIC VALUE!!!

The quantity of heat produced by the complete combustion of a given mass of a fuel, usually expressed in joules per kilogram.

There are two different types of heating value, which are the lower heating value (LHV) and the higher heating value (HHV). By definition the higher heating value is equal to the lower heating value with the addition of the heat of vaporization of the water content in the fuel.

DETERMINATION OF CALORIFIC VALUE

OF KEROSENE USING BOMB

CALORIMETER• This apparatus is primarily used to

determine the calorific value of any fuel (liquid or solid).

• Consists of a bucket filled with a known quantity of water, a steel bomb inside which an ignition coil is used to ignite the fuel whose calorific value is to be found.

• The whole system is insulated to any kind of heat losses.

HOW DOES THE BOMB

CALORIMETER WORK???Firstly, a known quantity of fuel whose Calorific Value is to be found is placed in the heater along with a bit of nichrome wire used for initiation of combustion.

This Steel bomb is closed and pressurized with oxygen (20 bar) and placed inside the bucket (filled with fixed quantity of water). This whole system is then sealed and the combustion is initiated.

The heat released by the fuel contributes to the rise in temperature of water, which becomes constant after the whole of the fuel is burnt.

THE EXPERIMENT

The experiment can be divided into 2 phases,

Phase 1 : Determination of WATER EQUIVALENT OF THE BOMB CALORIMETER by using a fuel of known Calorific value (BENZOIC ACID).

Phase 2 : Determination of the CALORIFIC VALUE OF KEROSENE by using the Water Equivalent of the Bomb Calorimeter.

PHASE 1

Calorific Value of Benzoic Acid : 26,460 kJ/kg

Mass of water : 1.6 kg

Mass of fuel : 1.23 g

ΔT = 2.06 °C.

Water Equivalent of Bomb Calorimeter = 0.666 kg

Mc x 4.18 x 103 x ΔT = Mf x C.Vf

PHASE 2

Mass of Kerosene = 0.8832 kg

ΔT = 3.88 °C

CVk = 41.75 MJ/kg

Mk x CVk = (Mw+ Mcal) x 4.18 x 103 x 3.88

DISCUSSIONS

The Experimental Value obtained is the LHV of Kerosene because of the fact that no water was left out in the products (i.e. a part of fuel energy has been utilized for the conversion of liquid water to vapor).

Experimental Value : 41.75 MJ/kg

Actual Value : 43 MJ/kg (LHV)

The difference between the actual and experimental values can be attributed to various reasons as discussed in the following slide.

SOURCES OF ERROR

A significant amount of heat loss occurs due to some gap at the stirrer – calorimeter interface.

A little amount of heat is lost due to conduction along the walls of the calorimeter.

Impurities in the fuel can also contribute to the difference in values.

The heat released by the nichrome wire can also be attributed for the variation.

REFERENCES

http://www.cement-co2-protocol.org/en/Content/Internet_Manual/tasks/lower_and_higher_heating_values.htm

en.wikipedia.org/wiki/Heat_of_combustion

http://www.britannica.com/EBchecked/topic/72493/bomb-calorimeter