M&C CG Series, Instruction Manual

Page: 12 / 35

12 CG-2 | 1.04.00 www.mc-techgroup.com
8.1 SELECTION OF THE APPROPRIATE CATALYST MATERIAL
For the conversion, as noted preliminary, two catalyst materials are available.
As a standard material, a carbon-molybdenum mixture
type C is used as catalyst. The carbon support-
ing material guarantees optimal contact between the gas to be converted and the surface of the catalyst
combined with a simultaneously low flow resistance.
The catalyst type C, operated within a flow range of 30
… 60 Nl/h, is able to convert NO
2
concentrations
up to 200 ppm to NO, achieving conversion ratios of >95 %. If necessary, the operating temperature of
the converter has to be raised within the admissible range.
N O T E !
For catalyst type C no oxygen in the sample gas as well as in the test gas is
necessary. A calibration with test gas NO
2
in N
2
is possible.
Alternatively, to type C, a cartridge with metal filling
type SS is available. It is possible to convert NO
2
concentrations of up to 2000 ppm into NO. A temperature adaption might also be necessary.
Figure 3 Notch to differentiate the two cartridge types
N O T E !
For catalyst type SS, oxygen in the sample gas as well as in the test gas
(> 1 vol% O
2
) is necessary. A calibration with NO
2
in N
2
is not possible.
8.2 SELECTION OF THE APPROPRIATE CATALYST TEMPERATURE
The converter with carbon-molybdenum cartridge filling is pre-adjusted to 350 °C [662 °F] in the factory.
In case of a metallic cartridge filling, the converter temperature is adjusted to 660 °C [1220 °F]. The
catalyst temperature can be adjusted continuously using the temperature controller on the front of the
converter (see chapter 18.2).
N O T E !
Depending on the gas composition and the flow temperature can be
adjusted and optimised within a certain level:
320 to 380°C
[608 to 716 °F], type C respectively
620 to 680°C [1148 to 1256 °F]. type SS.
Type SS