M&C TechGroup CG-2H-W_-2MH-W Operator's manual - Manual (Page 20)

20
Gas sampling and conditioning technology 9-0.2-ME
15 CLOSING DOWN
N O T E !
The location at which the converter is mounted must remain frost-free even
when the device is switched off !
No special measures need to be taken when the converter is taken out of operation for a short period.
In order to avoid unnecessary consumption of the catalyst and to ensure that the catalyst is ready for
use at short notice, the catalyst temperature should be reduced below 300°C in the "stand-by" during
brief operational pauses.
When the converter is taken out of operation for more protracted periods, we recommend purging the
converter with inert gas or air at ambient temperature, switching off the voltage and interrupting the
gas supply.
16 DETERMINING THE CATALYST SERVICE LIFE
The catalyst service life depends essentially on the following factors:

Converter-temperature

NO
2
concentration in the sample gas

O
2
concentration in the sample gas

Gas flow-rate

Interfering/carrier gases
Figures 6 up to 8 show the service life curves of the NO
2
/NO catalyst cartridge type C at 350°C de-
pending on the flow rate and the oxygen concentration. During the stated service life, conversion is
over 95%. If the degree of efficiency falls notably below 95%, the used catalyst cartridge should be
replaced (see 17.1).
The curve values are guide line values and are intended to enable the user to be better able to esti-
mate catalyst service life under practical conditions in the relevant installation.
N O T E !
Adverse conditions in the installation and long lasting increased converter
temperatures can lead to a substantially shorter catalyst service life !