Thermo Scientific Omni FTIR Multi Gas CEMS, Instruction Manual

Page: 83 / 254

Calibration
System Calibration Procedure Using Calibration Factor Table in Method
Thermo Fisher Scientific Omni FTIR Multi Gas CEMS Instruction Manual 4-19
Next to the gas item list shown above, there are three columns. The first
column is used to store the zero offset, the second column is used to store
the calibration factors and, the third column is used to store quadratic term
factors. Only the second column needs to be edited for the calibration.
Users can change the value by typing the new calibration factor and
clicking the “OK” button to save it.
Prior to performing the calibration, it is always recommended to keep a
record of the original calibration factors. Change the calibration factor to
“1.000” before running the certified gas into the gas cell. When performing
the system calibration, connect the certified gas cylinder to the port labeled
as “Span Check” on the right side panel of the system. You can also directly
connect the gas cylinder to the FTIR gas cell input. Run the system
normally by opening IMACC monitor and watch the measurement data
until it has stabilized as shown below. In this case, 20 % CO
2
is connected
to the system.
At least three data points should be averaged. In this example, the new
calibration factor should be the ratio of 20% over 19.77%. That is
“1.0116”. You can also open the “con file” from the directory C:\cons with
Microsoft Excel to calculate the average data.
There are 28 calibration factors listed in the Table 4–1 Calibration Factors.
For each calibration factor, the appropriate concentration range and H
2
O
content are listed. Gases with no H
2
O value should be calibrated with dry
certified gases. For those with an H
2
O content range, such as HCl_wet, the
calibration must be done in that wet condition.