Apex Instruments VSC-33 - Apex Instruments, Inc

% O
2
= oxygen content by volume (expressed as percent), dry basis
% CO
2
= carbon dioxide content by volume (expressed as percent), dry basis
F
O
= fuel factor; depends on type of fuel burned
20.9 = oxygen content in air by volume (expressed as percent), dry basis
Solving for F
O
, we obtain:
F
O
CO
=
O
−209
2
2
. %
%
The factor F
O
is mainly a function of the hydrogen to carbon ratio in the fuel. At zero percent
excess air, (i.e., when fuel is burned completely at stoichiometric conditions and the flue gas oxygen
concentration is zero) this equation simplifies to:
F
CO
O
ult
=
209
.
2
(% )
where (CO
)
2
ult
is the ultimate, or maximum, CO
2
concentration that the effluent gas is able to attain for the
given fuel. If the ultimate analysis of the fuel is known, the value of (CO
)
2
ult
can be calculated using the
following equation:
(% )
. % ( )
. % . % . % . % . %
CO
C
C H S N O
ult2
0321 100
153 364 057 014 0 46
=
+ + + −
where %C, %H, %S, %N, and %O are the percent by weight of carbon, hydrogen, sulfur, nitrogen, and
oxygen, respectively, as obtained from an ultimate analysis of the fuel.
The equations presented above can be used to check Orsat data or other analyses of oxygen
and carbon dioxide concentrations after they have been adjusted to a dry basis. This process simply
involves the comparison of the F
O
values obtained from the Orsat analysis with F
O
values calculated from
an ultimate analysis of the fuels being burned, or by comparison with published F
O
values.
VSC-33
APEX INSTRUMENTS, INC.
where:
17