Apex Instruments VSC-33 - Results And Calculations; Calculation of Results; Data Validation

where:
M
d
= Dry molecular weight, g/g·mole (lb/lb·mole)
%CO
2
= Percent CO
2
by volume, dry basis
%O
2
= Percent O
2
by volume, dry basis
%CO = Percent CO by volume, dry basis
%N
2
= Percent N
2
by volume, dry basis
0.280 = Molecular weight of CO or N
2
, divided by 100
0.320 = Molecular weight of O
2
, divided by 100
0.440 = Molecular weight of CO
2
, divided by 100
The concentrations of carbon dioxide, oxygen, and, if performed, carbon monoxide are measured
directly as the decrease in volume of the effluent gas sample after each analysis. The concentrations of
each of the constituents are calculated as follows:
% ( )CO V V
CO i2
2
= −
% ( )O V V
O CO2
2 2
= −
% ( )CO V V
CO O
= −
2
% ( % % % )N CO O CO= − − −100
2 2
where:
Vi = Initial burrette volume, ml (assumed to be 0)
V
CO
2
= Volume of gas sample as read on burette, after passes through CO
2
absorption
pipette, ml
V
O
2
= Volume of gas sample as read on burette, after passes through O
2
absorption
pipette, ml
V
CO
= Volume of gas sample as read on burette, after passes through CO absorption
pipette, ml
Data Validation
For any given fuel burned in air, a relationship between the oxygen (O
2
) and carbon dioxide
(CO
2
) concentrations exists. This relationship can be used to validate the results of the Orsat analysis
immediately after the analysis is completed based upon the type of fuel combusted. Since air is used for
the combustion process, the law of conservation of mass demands:
% .O F CO
O2 2
209+ =
VSC-33
APEX INSTRUMENTS, INC.
16