Page 14 - Petroleum and Gas Field Processing

Figure 2 Master gas system (MGS).

Field processing of natural gas, in general, is carried out for two main
reasons:
1. The necessity to remove impurities from the gas
2. The desirability of increasing liquid product recovery above that
obtained by conventional gas processing
Gas field processing units usually include the following:

1. Removal of water vapor: Gas dehydration represents the most
common needed unit in gas field processing. Water vapor seems to
be a universal impurity in natural gas. Water vapor is not
objectionable as such; however, the liquid or solid phase of water
is very troublesome. This is experienced when the gas is
compressed or cooled.
The liquid from of water accelerates corrosion of pipelines
and other related equipment. It also reduces pipeline capacity,
because it accumulates in low-point regions. Solid hydrates, on the
other hand, plug valves, fittings, and in some cases the pipe itself.
2. Acid gas separation: Acid gases basically imply hydrogen sulfide
and carbon dioxide (H 2 SandCO 2 ). Both gases are considered
impurities that must be removed from raw natural gas before it
can be marketed. Hydrogen sulfide is extremely toxic; when

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