Galvanic Applied Sciences AccuChrome MA2963, Operation Manual

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Revision 4 10 12/15/2018
Figure 2-9: Two Column Flow Diagram
2.4.2 4-Minute Analysis Cycle
The oven compartment for a typical 4-minute cycle time ACCUCHROME system is
composed of one Valco model DV22 10 port valve, one Valco model DV22 10 port valve and
four columns.
Four chromatography columns are used to facilitate the rapid analysis of the sample gas. All
components but C6+ pass through column 1, and C6+ is trapped by column 1 for a quick
back flush out. Column 2 allows for the rapid passage of nitrogen, methane, carbon dioxide
and ethane into column 3, while separating the heavier hydrocarbon components propane, i-
butane and n-butane, and i-pentane and n-pentane. Once ethane has entered column 3, the
six-port valve is actuated, trapping nitrogen, methane, carbon dioxide and ethane in column
3.
The heavier components pass through a jumper (marked in the diagram as R1), a short piece
of tubing containing no packing material, on their way to the detector. Once n-pentane has
eluted, the six-port valve is actuated a second time, and nitrogen, methane, carbon dioxide
and ethane then elute from column 3. Total analysis time is about 4 minutes, and as before
the analysis is run isothermally at 70
°
C. The gas flow path for the HSHV analysis is shown in
Figure 2-10.