White Pine news weekly mining review. [volume] (East Ely, Nev.) 1910-1920, 1920-08-22

In a report sen to the United States
bureau of mines, J. II. Virgins. as
slsta Mt petroleum engineer. says that
the evaporation of crude oil causes
one Of the largest single losses to
which the oil Is subjected after 1t Is
taken from the ground. The few days
which crude oil Is stored on the lease
before being taken by the pipe line
causes an aggregate loss per year
from evaporation estimated at 122.-
100000 gallons of gasoline In the mid
continent field alone. This has a value,
at % cents per gallon, of $26.880.0OO
and represents about 3 per cent OF the
total gasoline produced IN the United
States from all fields and all sources.
This problem is now being taken up
at the Bartlesville experimental sta
tion and at the San Francisco office
of the bureau Of mines. Mr.. Virgins
In preparing his report covered only
the mid-continent field, whose output
represents more than one-half the
United States production. Some OF
the important features of his report
are as follows:
Features Of Report
1.-The rate at which oil of given
quality and under given temperature
conditions will evaporate depends
chiefly on tho way 1t Is handled. The
ordinary method Is to pump the oil
from the well. force It through a pipe
line gathering system. and then into .
tank by means Of overshot connec-
lions. In this tank. called a flow tank.
any free water Is separated By grav-
ity. then the oil Is led by another pipe
to the lease storage tank. The latter
Is also filed by overshot connections
which permit the oil to fall 8 to 10
feet and splash into the tank. causing
spray. After standing In this tank
perhaps two to ten days the oil Is
run by the pipeline company By
means of pumps and pipe lines to the
large steel storage tanks. These have
bottom connections and nearly gas
tight roofs. The oil Is run from here
to large tank farms. or directly to the
refinery by pipe lines or tank cars.
Each Of these steps constitutes a
different class as regards rate Of evap-
Grafton. These classes may be divided
as follows: "a Filling a tank by over
shot connection; t2) filling a tank
by bottom connections; CD storage In
small unprotected tanks on the lease;
(4) storage In small tanks on the
lease which have some protection such
as shading or an alright jacket. and
90 storage In $1,000 or 5000 barrel
steel tanks which have so-called gas
tight roofs.
'FIllIng the tank by oyershot con-
nections Is the cause of the most rap
Id loss. The amount of this loss de-
ponds on several variables. such as
the height from which the oil falls.
the velocity and size of the stream,
and the size OF the tank as compared
with the time required to all II. Sew
eral tests we're made which show that
the loss I'm "a hours from such condi-
tons ranges from ] to 2h per cent Of
the original volume In the summer
time. Evaporation during the storage
on the lease In unprotected tanks
shows a high rate. Data obtained
from some OF the largest independent
producing companies In the mid-conti-
nent field show that the average period
Of storage Is FIVE days. In that time
oil stored In a 2JO-barreI steel tank.
unprotected. will lose 90 to 81 per
rent by volume; oil stored In 500.bar-
rel steel unprotected tanks. about 2
per cent a 1,00O-barrel wooden tank.
which is protected by n house that
acts both as a shade and ~wlndbreak.
will lose about IL per cent. The above
figures are for summer conditions. but
tests covering this phase Of the sub
ject were run for summer. autumn and
winter.
Conclusions Drawn.
data were kept on seml-montilly
losses In eighty 5000 and 37,OOO-bar-
rel steel tanks from which the average
evaporation loss vas computed. Re-
suits show that oil stored In such a
tank will In the first year lose 8 per
cent Of Its original volume. and In the
second year 81 per cent. giving q loss
for the first two years Of 81 per cent.
In considering evaporation losses OF
crude oil. one must remember that the
portion that escapes Is gasoline. and
moreover Is the lighter. o valuable
mart NJ the Oa aOlfno- This iipht 0anO.