Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a me~hod for collectin~
oil and dealing with and reducing the toxic and des~ructive
effects of oil spills by the use of an inert, non-toxic
material alone or in combination with other non-toxic and
inert materials. The oil with which this invention is concerned
is petroleum base oil and the term "oil" will henceforth be
used with this meaning. Spills of fuel oil present a
particular problem, both on land and water.
Oil spills have become of increasing concern due
to the ecological, environmental and atmospheric (oil evap-
oration) damage that is caused. Numerous schemes have been
proposed for collectin~, dispersing or neutralizing the ~ -
oil, but to date for various reasons, none has proven to be
entirely satisfactory. Generally the problem has been the
fact that by its very nature, oil when spilled, either on
land or water, is difficult to handle.
The object of this invention is to provide
processes and methods which will cause the oil to be absorbed
and adsorbed and thus to provide a product which can be readily
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~' 20 collected and/or disposed of.
' A further object of this invention is to provide
a composition or compositions which are particularly suitable
for use in such methods.
Another object is to produce a resultant by-product
~ having value as a fuel.
v In accordance with the method of this invention in
~g one aspect, diatomaceous earth is used to absorb and adsorb
- the oil in a proportion which will provide a clay-like product.~nder conditions of the use of Arabian light oil
of specific gravity 0.8581 and Saybolt Universal viscosity 67
at about ~0F., the ratio to provide such clay-like product
, is between 1:1 parts by volume of oil to diatomaceous earth and
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1:~ par-ts by volume of oil to diatomaceous earth. The
diatomaceous earth that was used came from California.
Variations in the source and type of oils and their viscos-
ities and densities,surface tensions, weather conditions and
prevailing temperatures may necessarily result in variations
to these proportions.
The combination of diatomaceous earth and
initially buoyant absorbent materials is particularly suitable
for use in practising the method of this invention applied to
oil spills on water where buoyan~y is desired to facili-~ate
recovery of the resultant floating clay-like product. This
is believed to be a novel composition and as such represents
a further aspect of this invention. Similarly, diatomaceous
earth by itself or in combination with denser particulate
materials is particularly suitable for use in practising
the method of this invention in cases where more rapid sinking
of the clay-like product is desired and is believed to be a
novel composition.
In the case of oil spills on land diatomaceous
earth may be applied without significant additives. The
proportion should be such as to produce a clay-like product
where it is desired to recover or remove the oil. But in some
case, such as a beach, it may be satisfactory to use an excess
of diatomaceous earth in which there is too small a proportion
of oil to act as a binder. ~he frangible diatomaceous earth
that has absorbed and adsorbed the oil is then merely left on
the beach.
In accordance with a further aspect of this
invention the combination of diatomaceous earth and oil provides
a product which can be shaped into briguettes or any other
convenient form and used as fuel. Other suitable substances
such as peat, hay and straw may be included.
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It has been found that as increasing parts of
diatomaceous earth are mixed with oil, certain significant
changes take place. Commencing first with one part of
diatomaceous earth to two parts of oil by volume, there is
merely thickening of the oil with no significant advantage
being obtained. However, at about equal parts of diatomaceous
earth to oil by vol~ne, a significant though not abrupt
transition occurs and the product is no longer oily to the
touch~ Instead it has a texture similar to that of soil having
a high clay content, with the oil acting as a binder to give
some degree o~ bonding between the individual particles of
diatomaceous earth. Such bonding is useful as it facilitates
the handling of the clay-like product.
Under conditions of oil density and viscosity
within the medium range, and at temperatures about 60F.,
it is best to use about four parts of diatomaceous earth
to one part of oil by volume. Larger amounts of diatomaceous
earth may be wasteful and furthermore substantially beyond
four parts of diatomaceous earth to one part of oil by volume,
~ 20 the binding effect of the oil diminishes to a low value.
,. . .
About four parts of diatomaceous earth to one part oil by
volume, therefore, under the stated conditions represents a
~ practical upper limit on the ratio of diatomaceous earth to
- oil by volume, where the achievement of such binding effect
is important. With heavy oil such as Bunker C oil, a larger
amount of diatomaceous earth should be used. About one part
of oil to 4 to 8 parts of diatomaceous earth is preferred.
In the case of oil spills on water, an important
parameter in the selection of a suitable ratio of diatomaceous
earth to oil is the time to initiation of sinking. The
appropriate ratio is dependent upon the viscosity and type of
spilt oil, the thickness and size of the oil layer, the
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temperature, the prevailing atmosphere and weather conditions,
includin~ the currents, water temperature, wind, rain and
wave size and form~
In accordance with one way of practising the
method of this invention, diatomaceous earth may be spread
on the spilled oil in the ratiG of from one to three parts
of diatomaceous earth to about one part of oil by volume.
The diatomaceous earth will absorb the oil and the resultant
clay-like product will fall to the bottom. As the oil will
be retained indefinitely in the pores of the diatomaceous
earth, the massive ecological damage caused by floating oil
slicks resulting from oil spills on water will be greatly
reduced, if not eliminated~ As, however, the possibility
arises that even in this absorbed form, some harm will be
~` caused to sensitive marine life, it may therefore be preferred
to cause the combination of diatomaceous earth and oil to
float for a sufficient period of time to enable it to be removea
mechanically from the surface of the water by suitable means such
as netting. Unfortunately, once diatomaceous earth has been
wetted it will sink. But it has been found that a mixture
of diatomaceous earth with an initially buoyant absorbent
fibrous material such as hay, straw or peat, together with
the absorbed oil, will float for a sufficient time for the
product to be removed mechanically. For example, one part
of hay to one part of diatomaceous earth to one part of oil
of medium viscosity, all by volume, will bat for a period
o~ approximately one week or more. Preferably the ratio
of diatomaceous earth to buoyant material should be 1:1 -
to 1:5 parts by volume. The ratio previously indicated,
namely, one to four parts of diatomaceous earth to one
part of oil by volume should be retained when diatomaceous
earth is used alone. However, it will be appreciated that
the hay or other fibrous material will absorb additional
oil. The amount of diatomaceous earth required may be reduced
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to an extent d~pendent on the oil absorbed by the fibrous
material. The diatomaceous earth combines with oil and in
so doing becomes a binder that links the fibrous material
to form a cohesive and durable floating "island".
Although the diatomaceous earth can be applied
to the oil physically mixed with the fibrous material, it may
be preferable in the case of the use of diatomaceous earth
combined with an initially buoyant fibrous material such as
dry hay, straw or peat, that the initially buoyant fibrous
material be applied to the oil in advance of the application
of the diatomaceous earth. In the case of peat, if the
diatomaceous earth is applied to oil mixed with the peat,
due to its fine size, the diatomaceous earth will quickly work
down through the peat and much of it may be lost. Once the
oil is present on the surface of the peat, it has a sufficient
binding effect to prevent significant loss of diatomaceous
earth. The composite product that results, whlch will float
for an appreciable period, may in the meanwhile, be skimmed
off using conventional-e~liEment, such as a scoop. The clay-like
texture resulting from the diatomaceous earth and oil will
consolidate the peat, and make it easier to handle. Other
natural or synthetic or buoyant materials such as hay, 6traw,
porous plastic known under the trademark STYROFOAM, polyure-
thane or polystyrene! which may be in the form of fibersJ
could be used in combination with the diatomaceous earth in
cases where buoyancy is desired, although their cost may be
high, and must be measured against the ecological benefit
from the operation. .
In accordance with the preferred method of this
invention which is believed to be unique, the following
procedure is followed: - a net is sunk through the oil, buoyant
material is applied to the oil, diatomaceous earth is applied
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with or subsequent to the application of the buoyant material
to develop the desired consolidation of buoyant material and
oil. Then the net is raised to remove the product fxom the
water and the product is dumped into suitable receptacles.
In cases where time is of the essence, for
example, where a spill is approaching a vulnerable location
such as a popu~ated land rnass, shore line, resort area, fish
spawning area, or shellfish ground, then diatomaceous earth
may be used alone or in combination with a more dense material
as a loading agent to accelerate -the sinking process before
the oil reaches the vulnerable location~ The oil will then
be absorbed and adsorbed and then rendered innocuous by being
deposited on the ocean bed at a non-critical location.
Processed and ground clays freely available and similar to
those in common use as absorbent cat litter have been found
to be effective loading agents, when mixed with diatomaceous
earth for this purpose. A suitable working proportion of
three parts of diatomaceous earth to one part of clay and one
part of oil, all by volume, has been found to be suitable for
medium oils at room temperatures. However, variations in
sinking times may occur depending on the type of oil, temper-
ature, weather and other conditions prevailing.
Another possibility where oil is approaching
a shore line is to apply diatomaceous earth to the shore as
a preventative measure, so that the oil will immediately be
absorbed before it causes damage.
A further serious problem resulting from large
scale oil spills is air pollution b~ oil vapour. Diatomaceous
earth, by its nature, tends to control the volatilization of
the lighter oil fractions of oil spills so as to minimize the
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effects on habitable areas of air which contains entrained oil.
It will be appreciated from the foregoing that
the method and composition of the invention provides a highly
useful and effective way of either collecting, dispelling or
nullifying oil spills. Diatomaceous earth is preferably applied
alone or with small amounts of additives in the case of oil
spills on land such as oil-well blowouts on land, ruptured
pipelines and other spills, which, though they take place on
water, result in oil being deposited on the beaches. In the
case of oil spills at sea, it will usually be preferable to
use the combination of diatomaceous earth and a fibrous buoyant
material as previously discussed. Suitable materials are
combustible products such as hay, straw or peat. In either
case, the product will be combustible. Briquettes can readily
be formed by shaping any of these products in moulds under
moderate pressure and temperature.
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