principles of managerial finance gitmanFull description
CALORIFIC VALUE OF FUELS y
y
y
It is defined as the heat liberated in kJ by complete combustion of 1 kg of fuel, solid or liquid. For gases it is the heat liberated in kJ per cubic metre at STP. For example: Fuel
kJ/kg
kCal/kg
Hydrogen
141900
33900
Butane
49200
11800
Diesel
45000
10700
Anthracite
27000
7800
Wood
15000
3600
Natural Gas
54000
13000
TYPES y
OF CALORIFIC VALUES
Higher Calorific Value:
It is the total heat liberated when all the products of combustion are brought back to pre-combustion temperature and in particular, condensing any vapour produced. (kJ/kg)
Calorific Value: It is determined by subtracting the latent heat of vaporization of the water produced from the Higher Calorific value. (kJ/kg) Thus, (HHV ) p = (LHV)p + m hfg (HHV )v = (LHV)v + m(ug uf) y
Lower
COMPARISON OF HCV AND LCV y
Here
is a comparison of HC V and LC V of some fuels.
FUEL
HCV
(MJ/kg)
HCV
(kj/mol)
LCV
(MJ/kg)
Hydrogen
141.80
286.00
121.00
Butane
49.50
20900
45.75
Gasoline
47.30
-
44.40
Propane
50.35
2220
46.35
Anthracite
2700
-
-
Kerosene
46.20
-
43.00
Paraffin
46.00
-
41.50
THE
JUNKERS GAS CALORIMETER
APPARATUS The apparatus mainly consists of a cylindrical shell with copper coil arranged in two pass configuration with water inlet and outlet to circulate through the copper coil, a pressure regulator, a wet type gas flow meter & a gas Bunsen burner, temperature sensors for measuring inlet, outlet water temperature, and for flue gas temperature and a measuring jar.
WORKING PRINCIPLE This Gas Calorimeter works on the Junker's principle of burning of a known volume of gas and imparting the heat with maximum efficiency to steadily flowing water and finding out of the rise in temperature of a measured volume of water. The formula, Calorific V alue of Gas X V olume of Gas = V olume of water X Rise in Temperature, is then used to determine the Calorific V alue of the Gas (assuming that heat capacity of water is unity).
DETERMINATION OF CALORIFIC VALUE y
y
y
This Calorimeter covers a wide range between 120 BTU (1000 to 26000 K Cal/m3). The Calorimeter is fixed on a tripod stand having levelling screws to keep the Calorimeter in perfectly vertical position. A constant water head maintenance device provided in the feed water pipe along with the inlet water flow regulator is fixed to the outer housing of the calorimeter.
PROCEDURE(Contd.) y
y
y
y
The gas source is connected to the pressure regulator, gas flow meter and the burner respectively in series. The water and gas flows are started to flow at a constant rate and the burner is lighted outside the calorimeter. The gas flow is regulated at a steady state to any designed flow (volume). The burner is inserted into the calorimeter and the outlet water is allowed to attain a steady temperature.
PROCEDURE(Contd.) y
y
The outlet is let into a 1000mL flask and started and the initial gas flow rate is noted. The time taken for the 1000mL flask to be filled and the final gas f low rate is also noted.
FORMULA TO BE USED C V g=( V w x w x CPw x T ) / V g x g where w is the density of water w is the volume of water collected in litres V CPw is the specific heat of water T is the change in temp. of water V g is the volume of gas burnt in litres g is the density of the gas burnt
APPLICATIONS y y y y y y y
Petroleum Industries Coke Oven Batteries Thermal Power Houses Cement Industries Fuel Gas Producers & Consumers Steel Plants Fertilizer Units
