Instrument Maintenance Model T101 Instruction Manual
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8.3.5. MAINTAINING THE H2S SO2 CONVERTER
The catalyst contained in the H2S SO2 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 H2S into SO2 for up to 6000
ppm/hours. This means that if the H2S 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 H2S 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 H2S SO2 converter will operate efficiently:
1. Measure the amount of H2S in the sample gas.
2. Divide 6000 by the H2S concentration.
EXAMPLE: If the H2S concentration is 750 ppb:
Operational hours= 6000 ppm/hr ÷ 0.75 ppm
Operational hours= 6,00,000 ppb/hr ÷ 750 ppb
Operational hours= 8000 hrs
8.3.5.2. Checking the Efficiency of the H2S SO2 Converter
To check to see if your H2S SO2 converter is operating properly:
1. Set the analyzer to SO2 measurement mode (see Section 4.5.1).
2. Supply a gas with a known concentration of SO2 to the sample gas inlet
of the analyzer.
3. Wait until the analyzer’s SO2 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 SO2 concentration
5. Set the analyzer to H2S measurement mode (see Section 4.5.1).
6. Supply a gas with a known concentration of H2S, equal to that of the SO2
gas used in steps 2-4 above, to the sample gas inlet of the analyzer.
7. Wait until the analyzer’s SO2 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 H2S concentration
9. Divide the H2S concentration by the SO2 concentration
EXAMPLE: If the SO2 and H2S concentration of the two test gases used is
500 ppb:
Measured SO2 concentration = 499.1 ppb
Measured H2S concentration = 490.3 ppb
07266B DCN6485