| SRI
has enhanced its popular Multi-Gas
Analyzer #1 GC to simultaneously monitor low levels ( <
50 ppm ) of sulfur compounds by adding an FPD/FID combined
detector, which selectively detects sulfur down to
mid-ppb range
and a nickel sample loop. Many analysts require natural gas analysis
for BTU value calculations or drilling and mudlogging
applications
and frequently sulfur compounds are also of
interest.
Sulfur
disappears on contact with hot stainless steel surfaces.
Even limited contact with a hot stainless steel sample loop
will destroy any sulfur in the gas sample. If the sulfur
compound makes it through the column and into the TCD
detector, no sulfur emerges from the TCD for detection by the
FPD.
The solution
is to use a special nickel sample loop which is mounted
outside the valve oven at room temperature, and special fused
silica lined transfer lines leading to a splitter and a 60
meter thick film capillary column. While Teflon columns
are sometimes also used for sulfur analysis, the natural gas
analysis ( using molecular sieve and silica gel ) requires
column temperatures of 250°C or higher, and since the sulfur
column is located in the same column oven, it is essential to
use a column like the 60 meter capillary which can tolerate
the higher temperatures.
The Multiple Gas Analyzer + Sulfur
GC is pre-plumbed and ready to resolve sulfur compounds via the
combined FPD/FID; H2, O2,
N2, Methane, and other compounds above 500ppm via the TCD, and
C1
through C6 and CO2 (as converted to methane via the methanizer)
via the single FID.
A detailed system overview on the operation of the Multi-Gas Analyzer can be viewed
here (1.5mB .pdf file - you will need Adobe Acrobat Reader to view this
file).
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