The border vidette., 1931-11-14
ThE USE OF ALUMINIUM FOR
OIL LEASE TANKS

! The corrosive action of con
centrated brines on aluminium
tank plates under different oper.
ating conditions is described by
the United States Bureau of
Mines, Department of Commerce.
ia the second of series of reports
on the use of aluminium for oil
lease.tanks.
! The resulting of one year
test made on an oil lease in the
So called sour district" near
Berger, Texas, where free hydro
gen sulphide accompanied the
production of oil. gas. and salt
water, proved that aluminium
lease tanks will withstand corro
sion by hydrogen sulphide; but
it was found that aluminium
was susceptible to attack by salt
water which was invariable pre-
sent in certain portions of tanks,
and that hydrogen sulphide ac-
CELEBRATED this salt water corro
sion in an indirect manner, state
the authors. Ludw wing Schmidt,
John M. Devine, and 0. j. Will
helm.
In order to study corrosion
conditions encountered in the
tanks during the test period. a
laboratory was maintained at the
site of the aluminium lease tanks.
All metals have an inherent
tendency to go into solution
when in contact with water. The
extent of this tendency varies
for different metals, depending
upon their position in the cleo
tromotive series. Investigators
generally agree that aluminium
owes its resistance to corrosion
to the protective action of sup
erficial layer of oxide which is
esta ablished in sites by auteoxida
ton. lnasmuch as the metal it
self is located relatively high in
the electromotive series, it is
evident that any set of conditions
whereby the oxide film is ruptur
| ed or rendered pervious to aque
Gus solutions will result in rapid
corrosion of the metal when in
contact with such solutions.
The potential corrosive agents
to which the aluminium tanks
we're subjected in service includ
ed natural gas, oil, and salt
water, each of which contained
free hydrogen-sulphite gas in
varying proportions. The feld
test proved that natural gas oil
were without corrosive effect on
the tanks. The salt water, how
ever, was capable of producing
serious corrosion. Hydrogen
sulphide, in dissolved or free
state. did not have any directac
ton on the tanks, but indirectly
it was a contributory factor to
corrosion through the production
of iron sulphide by interaction
with the steel flow lines. Iron
sulphide. so formed, was flushed
into the tanks and funtioned as
1accelerator to salt water zorro
sion.
All the corrosion in the alumi
mum tanks was of highly local
lied nature. resulting in a pitting
attack. Nevertheless, it was pos
sible to identify three distinct
types of corrosion:
CD Low temperature a t.
water corrosion, which was en-
countered where aluminium side
sheets of tanks we're exposed to
the action of salt water.
..(2) High-temperature a t.
water corrosion, which was en-
countered ie the corrosion of al.
uminum steam-heating coil 8
within tanks.
(3) Bimetallic corrosion, W hich
was caused or accelerated by the
proximity of steel in electrical
contact with aluminium; such
corrosion resulted where steel
steam heating coils were install
ed ia aluminium tanks.
Further details are given in
Report of Investigations 1881,
The use of aluminium for oil
lease tanks; Part II-Laboratory
tests" copies of whidh may be
obtained from the u. S. Bureau
of Mines, Department of Com
merce. Washington, D. G.