A method is provided for controlling superheating and temperature of a
compressed natural gas stream and the addition of a corrision inhibitor
composition for transmission through a pipeline that includes: a.
dividing a stream of natural gas discharged from a high pressure gas
compressor (106) into a first portion (108) and a second portion (202);
b. passing the first portion (108) of the gas from the gas compressor to
a heat exchanger (112) to heat the gas to a predetermined temperature; c.
passing the first portion of gas (111) exiting the heat exchanger to an
aftercooler (114); d. passing the second portion (202) of natural gas
discharged from the gas compressor (106) to the aftercooler (114) without
passing it through the heat exchanger (112), the second portion of gas
and the first portion of gas being mixed at the aftercooler inlet and
cooled by the aftercooler and discharged from the aftercooler as a cooled
gas stream (116) having a temperature no greater than a first
temperature; e. passing the cooled gas stream (116) from the aftercooler
to a liquid discharge drum (118) to remove condensate from the cooled gas
and discharging from the drum a partially dried gas stream (120) at a
second temperature; f. passing the partially dried gas stream (120) from
the discharge drum to the heat exchanger (112) in heat exchanging
relation with the first portion of gas (108) from the gas compressor, and
superheating at least a portion of the gas stream (120) to a third
temperature to provide a superheated gas stream (129), the third
temperature being controlled by an automated control loop responsive to a
differential pressure across the gas compressor (106); and g. passing the
superheated gas stream (129) into a transmission tie-line (256) and
injecting a predetermined amount of a corrosion inhibitor composition
into the tie-line to mix with the superheated gas stream, where the
amount of corrosion inhibitor injected is proportioned in response to the
third temperature.