Emerson X-STREAM XE - Page 94

Emerson Process Management GmbH & Co. OHG3-20
X-STREAM XE
Instruction Manual
HASXEE-IM-HS
10/2012
3.5 Hydrogen Sulde (H
2
S) Measurement
Interfering
Gas
ppm
applied
% Interference related to full scale (f. s.)
Measurement range H
2
S
0 to 50 ppm 0 to 200 ppm 0 to 2000 ppm
CO 400 4 4 1
H
2
400 0.2 1 0.25
SO
2
20 20 18 10
NO
2
10 -25 -30 -30
NO 50 10 2 3
Cl
2
10 -12 -25 -25
C
2
H
4
400 0.25 0.8 0.1
NH
3
20 0.1 0.1 0.1
Tab. 3-8:
Electrochemical H
2
S Measurement - Cross Interference by Accompanying Gases
3.5.1 Cross Interferences by Accompanying Gases
Moisture and oxygen are needed in the sample
gas for the electrochemical reactions to take
place. If concentrations of above components
are too low, the sensor's sensitivity decreases.
Therefore a purge cycle with ambient air can
be implemented by programming the internal
PLC.
If this option has not been ordered, the cu-
stomer is responsible to take care of regularly
purging the sensor. See the separate docu-
mentation provided together with every sensor
for information on how to properly setup such
a procedure.