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4-7
Flue Gas Analysis System Operation 4
TELEDYNE BROWN ENGINEERING
Analytical Instruments
4.2.2 Span Gas
It is recommended that the span gas have a concentration of 4.0–4.8%
methane or other desired combustible gas with the balance being nitrogen.
Note: It is important that the dilution air flow is never turned off during
operation or calibration. Combustibles without at least a 2 : 1 ratio
of oxygen should never be allowed to flow past the sensor. If this
occurs, a loss of sensitivity will result and the unit will require
complete recalibration and possible sensor replacement.
Note: The range of the combustible monitor is 0–5% combustibles,
however, it is actually operating, at a sensitivitv of 0–2.5% combus-
tibles (methane equivalvent) due to the 1 : 1 dilution with air.
4. 3 System Startup
4.3.1 Analyzer Startup
Refer to Sections 4.1 and 4.2 for startup procedures for the oxygen
and combustibles analyzers, respectively.
4.3.2 Sample System Startup
Start the pump by turning ON the oxygen analyzer RANGE switch.
Then turn on the water by opening the shutoff valve inside the case. Water
should be observed passing through the transparent plastic hoses. Water
flow rate will be determined by the supply pressure. With 10 psig, flow
rate will be approximately
1
/4 gpm maximum pressure should be 100 psig.
This will give a flow rate of about 1
1
/2 gpm. Generally, the dirtier the
sample, the more water required. However, a
1
/4 gpm flow rate will nor-
mally be adequate, and the pressure should be reduced accordingly.
After analyzer startup and calibration procedures have been accom-
plished, make certain that the sample-calibration selector valve is in the
proper position to draw in the sample (see the cautionary note in step (2) of
Section 4.1.4, Initial Calibration and Equilibration, and step (5)).