Teledyne T101, Operation Manual, Page: 210 / 375

Instrument Maintenance Teledyne ML - T101 Operation Manual
206
8.3.5. MAINTAINING THE H
2
S

SO
2
CONVERTER
The catalyst contained in the H
2
S

SO
2
converter of your T101 must be replaced
periodically in order for the analyzer to continue measuring H2S accurately and
reliability.
This material is capable of efficiently converting H
2
S into SO
2
for up to 6000
ppm/hours. This means that if the H
2
S content of the sample gas is typically around 600
ppb, the scrubber will function for approximately 10 000 hours, a little over 13 months.
If, however, the typical ambient H
2
S level of the sample gas is 1000 ppb, the scrubber
would only last for approximately 6000 hours or about 8 months.
8.3.5.1. Predicting When the Converter Catalyst Should Be Replaced.
To determine how long the H
2
S

SO
2
converter will operate efficiently:
1. Measure the amount of H
2
S in the sample gas.
2. Divide 6000 by the H
2
S concentration.
EXAMPLE: If the H
2
S concentration is 750 ppb:
Operational hours= 6000 ppm/hr ÷ 0.75 ppm
Operational hours= 6,000,000 ppb/hr ÷ 750 ppb
Operational hours= 8000 hrs
8.3.5.2. Checking the Efficiency of the H
2
S

SO
2
Converter
To check to see if your H
2
S

SO
2
converter is operating properly:
1. Set the analyzer to SO
2
measurement mode (see Section 4.5.1).
2. Supply a gas with a known concentration of SO
2
to the sample gas inlet
of the analyzer.
3. Wait until the analyzer’s SO
2
concentration measurement stabilizes. This
can be determined by setting the analyzer’s display to show the SO2
STB test function (see Section 4.2.1) SO2 STB should be 0.5 ppb or
less before proceeding.
4. Record the stable SO
2
concentration
5. Set the analyzer to H
2
S measurement mode (see Section 4.5.1).
6. Supply a gas with a known concentration of H
2
S, equal to that of the SO
2
gas used in steps 2-4 above, to the sample gas inlet of the analyzer.
7. Wait until the analyzer’s SO
2
concentration measurement stabilizes. This
can be determined by setting the analyzer’s display to show the H2S
STB test function (see Section 4.2.1) H2S STB should be 0.5 ppb or
less before proceeding.
8. Record the stable H
2
S concentration
9. Divide the H
2
S concentration by the SO
2
concentration
EXAMPLE: If the SO
2
and H
2
S concentration of the two test gases used is
500 ppb:
Measured SO
2
concentration = 499.1 ppb
Measured H
2
S concentration = 490.3 ppb