Specifications

S
TARTUP AND
O
PERATION
748410-A
August 1999
21
Chemiluminescense Detector Analyzer Module
Rosemount Analytical NGA 2000
3
6. Open valve MV2 until the CLD Module SAMPLE Pressure Gauge reaches operating
pressure and the BYPASS flowmeter indicates some bypass flow. Wait until stable
readings are obtained by the CLD Module.
7. Zero and span the Analyzer output to indicate the value of the NO concentration being
used. This value should be about 80% of fullscale. Record this concentration.
8. Open valve MV1 (air supply metering valve) and adjust to blend enough air to lower the
NO concentration (as noted above) about 10%. Record this concentration.
9. Power up the ozonator, and increase its supply voltage until the NO concentration noted
in Step 8 is reduced to about 20 percent of the concentration noted in Step 7. Wait for
stabilization. NO
2
is now being formed from the NO + O
3
reaction. There must always be
at least 10 percent unreacted NO at this point. Record this concentration.
10. Switch the CLD Module to NOx mode. Total NOx concentration is now output to the
network for display. Record this concentration.
11. Turn off the ozonator, and allow the Analyzer reading to stabilize. Total NOx
concentration of the dilute NO span gas initially used is displayed. Record this
concentration.
12. Close valve MV1. The NO concentration should be equal to or greater than the reading
in Step 7. This indicates whether the NO contains any NO
2
.
13. Calculate the efficiency of the NO converter by substituting the concen-trations obtained
during the test in the equation below:
Where:
a = recorded concentration in Step 10
b = recorded concentration in Step 11
c = recorded concentration in Step 8
d = recorded concentration in Step 9
In the example in Figure 3-7B, the following calculations would apply:
Efficiency checks should be made on each analyzer range, using an NO span gas
concentration appropriate to the instrument range.
a - b
c - d
% Efficiency = 1 + 100
% Efficiency = 1 + 100 = 92%
80 - 85
80 - 20