Extended Natural Gas Analyzer - NGA-2
Natural gas is a
widely used resource. Its monetary value is based largely on its heating value
or BTU content. Gas chromatographic methods published by the Gas Processors
Association (GPA methods 2261 and 2177) for the analysis of natural gas are not
only used to analyze natural gas for composition but are ideal mechanisms for
calculating the BTU content, as well as other physical properties such as
specific gravity and compressibility.
The chromatograms below
show examples from our NGA-2 extended natural gas analyzer, which is
recommended for the analysis of gases with moderate concentrations of heavy
components, or for natural gas condensates. With this GC system, all of the
heavier (C6 and above) hydrocarbons pass through the analytical column making
more accurate BTU calculations possible.

This system is
usually equipped with our flow-through vaporizing inlet system which permits
the analyses of both gas and liquid samples with the same sample plumbing and
injection valve schemes, reducing complexity and costs. Separate gas and liquid
sampling valve versions are also available. The basic assay chromatogram above
shows the separation of hydrogen from helium. Renewed interests in helium
sources have resulted in our adding this as an optional feature to the NGA-2.
The trace level sulfur compound analysis seen above (which is capable of ppb
level analyses) is also optional on the NGA-2.
When not being used for natural gas or natural gas condensate samples, the system can function as a general purpose split injection capillary GC equipped with a 60 m x 0.25mm boiling point column. If the sulfur selective detection scheme is also purchased, you then have a general purpose GC capable of simultaneous FID and sulfur selective analyses. The TCD side of the GC performs an analysis that is also applicable to many other samples requiring determination of fixed gases such as oxygen, nitrogen, methane, carbon monoxide and carbon dioxide. This part of the NGA-2 uses a backflush scheme so the heavier hydrocarbons in a particular sample are irrelevant. The features and unique options on the NGA-2 make it a very flexible GC system performing analyses that in many laboratories are being conducted on 4 or more GC's.
Chromatographic Instruments Company
979-236-4671, e-mail home