careful to observe the level of the disorbent solution in the carbon dioxide pipette. When the level
of the disorbent solution in the carbon dioxide pipette reaches the capillary, crimp the tubing on
the leveling bottle. Observe the level of the meniscus in the burette.
c. Continuously repeat Step B until the amount of carbon
dioxide absorbed from the sample (e.g., the level of the
meniscus) does not change. Typically, three passes of
the sample through the absorption pipette is sufficient
for the complete absorption of CO
2
. Close the stopcock
on the burette and on the CO
2
pipette and record the
position of the meniscus. To ensure the correct reading
of the meniscus, hold the aspirator bottle as shown
inFigure
7
.
d. Open the stopcock on the burette to the oxygen
absorption pipette, and open the stopcock on the
oxygen absorption pipette.
e. Raise the leveling bottle so that the confining solution
fills the burette. When the confining solution reaches
the top of the capillary, crimp the rubber tubing. Lower
the leveling bottle, being careful to observe the level of
the oxysorbent solution in the oxygen pipette. When the
level of the oxysorbent solution in the oxygen pipette
reaches the capillary, crimp the tubing on the leveling
bottle. Observe the level of the meniscus in the burette.
f.
Repeat the previous step until the amount of oxygen
absorbed from the sample (the level of the meniscus) does not change. Typically six passes of
the sample through the absorption pipette is sufficient for the complete absorption of O
2
. Close
the stopcock on the burette and on the O
2
pipette and record the position of the meniscus.
g. If carbon monoxide analysis is desired open the stopcock on the burette to the carbon monoxide
absorption pipette, and open the stopcock on the carbon monoxide absorption pipette.
h. Raise the leveling bottle so that the confining solution fills the burette. When the confining
solution reaches the top of the capillary, crimp the rubber tubing. Lower the leveling bottle, being
careful to observe the level of the cosorbent solution in the carbon monoxide pipette. When the
level of the cosorbent solution in the carbon monoxide pipette reaches the capillary, crimp the
tubing on the leveling bottle. Observe the level of the meniscus in the burette.
i.
Repeat the previous step until the amount of carbon monoxide absorbed from the sample (the
level of the meniscus) does not change. Typi cally, three passes of the sample through the
absorption pipette is sufficient for the complete absorption of CO. Close the stopcock on the
burette and on the CO pipette and record the position of the meniscus.
V.
Results And Calculations
Calculation of Results
The results of carbon dioxide and oxygen analyses are used to calculate the dry molecular
weight, M
d
, of an effluent gas. M
d
is used in conjunction with data from velocity and temperature
traverses and moisture measurements to calculate the velocity and volumetric flow rate of an effluent
gas. Stack gas molecular weight is calculated according to the following equation:
M
CO
O
N
CO
=
d
+
+
+
0 440
0 320
0 280
2
2
2
.
(%
)
.
(%
)
.
(%
%
)
Figure 7 Measuring Sample
Volume using Leveling Bottle
VSC-33
APEX INSTRUMENTS, INC.
15