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Calibration
Equipment Required
Equipment Required
Zero Gas Generator
Compression
4-2
42iQTL Instruction Manual
The quantitative nature of this reaction is such that when the NO
concentration is known, the concentration of NO
Ozone is added to excess NO in a dynamic calibration system, and the NO
channel of the chemiluminescence NO-NO
indicator of changes in NO concentration.
When O
calibrated NO channel is equivalent to the concentration of NO
produced. Adding variable amounts of O
change the amount of NO
The following equipment is required to calibrate the analyzer:
Zero gas generator
●
Gas phase titrator
●
A zero air source, such as a Thermo Scientific 111iQ Zero Air Supply, free
of contaminants such as NO, NO
calibration, and gas phase titration.
The zero air source should be at an elevated pressure to allow accurate and
reproducible flow control and to aid in subsequent operations such as
drying, oxidation, and scrubbing. An air compressor that gives an output of
10 psig is usually sufficient for most applications.
Drying
Several drying methods are available. Passing the compressed air through a
bed of silica gel, using a heatless air dryer, or removing water vapor with a
permeation dryer, are three possible approaches.
Oxidation
NO is usually oxidized to NO
can be accomplished by either ozonation or chemical contact. During
ozonation, the air is passed through an ozone generator. The O
produced reacts with the NO to form NO
sufficient residence time for the ozonation reaction to go to completion.
Chemical oxidation is accomplished by passing the air stream through a
reacting bed. Such agents as CrO
very efficient at oxidizing NO to NO
the advantage of needing no electrical power input for its application.
NO
+
O
NO
3
is added, the decrease in NO concentration observed on the
3
generated.
2
2
+
O
2
2
can be determined.
2
-NO
analyzer is used as an
2
x
from a stable O
3
, and O
is required for dilution,
2
3
in order to ease its scrubbing. Oxidation
. Care must be taken to allow
2
on an alumina support or Purafil® are
3
. The chemical contact approach has
2
2
generator can
3
that is
3
Thermo Scientific
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