Engineering Chemistry S Datta

404 ENGINEERING CHEMISTRY
Filter
Stop cock
Water
reservoir
Gases
tube
Flue
gas
Graduated
Burette
Fused CaCl 2
Bulb Bulb
containing containing
AM.Cu 2 Cl 2 Alkaline
pyrogalic
acid
Bulb
containing
KOH
solution
Rubber
tube
Fig. 18.16
Procedure
• The apparatus is tested for its air-lightness.
• The flue gas (100 ml) is taken in the apparatus in the measuring burette by adjusting
the volume by water reservoir atmospheric pressure.
• The stopper (1) is opened for CO 2
absorption and water reservoir is raised to force the
gas inside the bulb. The gas is finally taken in the burette and the volume of the gas is
measured by making the levels of water inside the burette and water reservoir equal.
The decrease in volume gives the percentage by volume of CO 2
in the flue gas.
• The stopper (2) is opened and provided as usual to get the percentage by volume of O 2
in the flue gas.
• The stopper (3) is opened and proceeded as usual to get the percentage by volume of CO
in the gas.
• The sequence of the bulbs should be strictly followed.
Implications of the Analysis
• If the flue gas contains greater percentage of CO it is implied that considerable wastage
of fuel is taking place due to incomplete combustion and the O 2
supply is insufficient.
• The greater percentage of O 2
in the flue gas indicates that O 2
supply is in excess.
• Result of the analysis will help to control the combustion process.
SOLVED EXAMPLES
Example 1. A sample of coal contains:
C = 93%, H = 6% and ash = 1%
Calculate the gross and net calorific V value of the coal from the following data:
Weight of coal burnt (m) = 0.92 g
Weight of water taken (w) = 550 g