EN
16.1.2023
Official Journal of the European Union
L 14/205
Figure 11 Schematic flow diagram of methane analysis with the NMC
A.2.1.5.
Components of Figure 11 NMC
Non-methane cutter
To oxidize all hydrocarbons except methane HC Heated flame ionization detector (HFID) or flame ionization detector (FID) to measure the HC and CH4 concentrations.
The temperature of the HFID shall be kept at 453 K to 473 K (180 °C to 200 °C).
V1
Selector valve
To select zero and span gas R
Pressure regulator
To control the pressure in the sampling line and the flow to the HFID A.2.2.
Dilution and particulate sampling system
A.2.2.1.
Description of partial flow system A dilution system is described based upon the dilution of a part of the exhaust stream.
Splitting of the exhaust stream and the following dilution process may be done by different dilution system types.
For subsequent collection of the particulates, the entire dilute exhaust gas or only a portion of the dilute exhaust gas is passed to the particulate sampling system.
The first method is referred to as total sampling type, the second method as fractional sampling type.
The calculation of the dilution ratio depends upon the type of system used.
With the total sampling system as shown in Figure 12, raw exhaust gas is transferred from the exhaust pipe (EP) to the dilution tunnel (DT) through the sampling probe (SP) and the transfer tube (TT).
The total flow through the tunnel is adjusted with the flow controller FC2 and the sampling pump (P) of the particulate sampling system (see Figure 16).
The diluent flow is controlled by the flow controller FC1, which may use qmew or qmaw and qmf as command signals, for the desired exhaust split.
The sample flow into DT is the difference of the total flow and the diluent flow.
The diluent flow rate is measured with the flow measurement device FM1, the total flow rate with the flow measurement device FM3 of the particulate sampling system (see Figure 16).
The dilution ratio is calculated from these two flow rates.