Page 464 - Pipeline Pigging Technology

Internal cleaning and coating

CASE STUDIES

Many types of line have been successfully coated by the "double-plug
extrusion" process. They include: potable water, raw water, brine, crude oil,
refinery off gas, jet fuel, isopropyl alcohol, ethylene glycol, and others. Below
are a few case studies.

Chemical solvent lines at shipping terminal
A large chemical producer coated 2000ft of new, buried 6-in carbon steel
pipe to prevent iron and corrosion from contaminating several water-white
chemicals. Their alternative, stainless steel pipe, would have cost up to ten
times that of coating carbon steel.

Jet fuel lines at military base
Several military installations have coated jet fuel lines, both new and old,
in order to prevent contamination from internal corrosion. Their alternative,
cleaning and dewatering the fuel with filters and separators, was more costly
and less reliable.

Water feed to steam generator used in crude oil production
An oil producer that uses steam for down-hole injection coated 5.5 miles
of 10-in new water lines to the steam generators to prevent corrosion from
contaminating the generators. Their alternative, pre-coated, or yard-coated,
pipe was about 40% more expensive, and would leave coating gaps at the
joints.

Boiler feed water line in refinery
A major refinery coated 1600ft of 4-in boiler feed water line which had
severe flow restriction due to tuberculation. Their alternative, replacement
of the pipe, was twice as expensive and would take much longer than coating.

Wet natural gas gathering lines
A major utility company coated 4.3 miles of 6-in and 4 miles of 4-in new
natural gas gathering lines. The lines were being chemically treated with
corrosion inhibitors, but the customer wanted additional protection in an
environmentally-sensitive area.

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