Note: Descriptions are shown in the official language in which they were submitted.
~l.2~3~7
BACKGROUND OF TAO MENTION
Field of the Invention
Thus invention relates to a process for repining
and separating all petroleums and/or related materials,
including natural materials Couch as, petroleum gas,
crude oils, bitumens, oils from oil-sands or oil-shales,
tars from tar-sands, etc.), petroleum fraction or fractions
derived from said natural materials, and refinery streams
and products and, more particularly is concerned with a
novel method for removing and separating asphaltic
constituents and/or nonhydrocar~on constituents by
contacting said petroleums Andre said related materials
with an added asphaltenes, precipitating said constituents
together with said added asphaltenes, and recovering an
oil (Andre gas) having a reduced concentration of said
constituents. In Ayers processes according to the
method provided by the present invention, an asphalt
or asphaltenes can also be recovered.
Description of Prior Art
Feed stocks for cracking processes are now usually
the residue or heavy distillate from a distillation
sequence However, as the occasion demands, whole cruxes
may also serve as the cracking ~eedstocks and, when this
is the case, the crude must be desalted prior to the
cracking process. Like still residue, heavy crude
petroleums usually contain substantial amounts of asphalt
tic constituents, which are not only regarded as the coke-
forming constituents in many thermal processes but also
the source of carbon depositing on the catalyst for
cracking process, thus limiting the service life of the
catalyst and the capacity of the catalytic cracking unit.
Crude oils contain appreciable amounts o organic non-
hydrocarbon constituents, mainly sulfur-, nitrogen, and
oxygen-containing compounds r in smaller amounts, organ-
metallic compounds in solution and inorganic salts in colloidal suspension with asp~altenes and resins. These
constituents appear throughout the entire boiling range
I,
. ,
~2;~3~7
2 --
of the crude oil jut do tend to concentrate mainly in
the nonvolatile fractions especially asph~ltenes and
resins In minute amounts, these compounds can cause
serious corrosion problems, catalyst deactivation,
degrading of product quality, health hazard, etch
In general, there is an approximate correlation
between the content of the non hydrocarbon constituents
and the content of the asphaltic constituents of a
petroleum stock - the higher the asphaltic constituents
content, the higher the non hydrocarbon constituents
content. It is, therefore often deemed necessary that
the asphaltic constituents be removed from feed stocks
for cracking and other refining processes.
There are a number of methods which are directed
at upgrading feed stocks and separating petroleums and
related materials by removal of the asphaltic con-
stituents and the non hydrocarbon constituents. These
conventional methods and processes may be summarized
as follows:
1. Flash distillation
I Vacuum flashing
3. viscosity breaking
4. Coking
I Solvent treatment
6. Caustic treatment
7. Gas trea~nent
I Ox dative treatment
I Adsorbent treatment
10. Acid treatment
11. Precipitation with reactive metal salts,
etc.
The solvent treatment method is most effective in
removing the asphaltic constituents, however it has been
subject to considerable economic and operational dozed-
vantages as all other conventional methods have, which
often require special equipment Andre severe operating
conditions Most of these conventional methods are not
933L7
3 -
applicable to the treatment of crude petroleums because
of the large volumes and the high treatment costs Some
of these methods produce wastes which require special
handling, and pose serious disposal problems.
Object of' the 'Inanition
In view of the above, a principal object of the
present invention is to provide a novel method for
simultaneously removing both the asphaltic constituents
and the non hydrocarbon constituents from petroleums
I Andre related materials, which avoid the difficulties
normally associated with conventional method. In par-
titular, it is an object of this invention to provide a
simple but effective method for economically refining
and separating crude petroleums in large volumes.
Another primary object of the invention is to
provide a novel method for refining petroleums and/or
related materials and, at the same time, economically
recovering asphaltenes, which have not been commercially
produced to any significant extent due to the high
recovery cost of the conventional methods. Asphaltenes
have been known -to have numerous important potential
usages
Other important objects of the present invention
are: 1) to provide a novel method for refining petrol-
ems and/or related materials, which employs only petroleum fractions and no foreign substances; I to
provide a novel method for refining petroleums and/or
related materials which can be carried out in conjunction
with many conventional methods, 3) to provide a novel
method for relining petroleums and/or related materials
which has relatively small energy requirements; 4) to
provide a novel method for reunion petroleums Andre
related materials which can be carried out without
special, costly equipment or hazardous operating con
dictions; I to provide a novel method for relining petrol
Lucy Andre related materials which produces no waste
stream; and 6) to provide a novel method for refining
I i ,
I. ,;
.
~2~3~
petroleums Andre related laterals which can be
easily applied to feed stocks having a wide range ox
chemical composition and ox physical properties, with
out requiring the major modification of its equipment
and operating conditions.
Summary of the Invention
In accordance with the present invention, a
petroleum or related material is rapidly and effectively
refined by the removal of the asphaltic constituents and
the non hydrocarbon constituents from the former by
contacting same with an added asphaltenes, preferably
those derived prom the same feed stock being treated,
and then precipitating and separating said asphaltic
constituents and said non hydrocarbon constituents
together with said added asphaltenes to recover the oil
fractions remaining Under the above conditions, it has
been found by the present inventor that the asphaltenes
added to the fed stock will attract and associate with
the resins and other heavy aromatics which are contained
in said stock, and thus breaking the equilibria existing
amount the asphaltic compounds and other heavy aromatic
compounds. The breaking of said equilibria results in
the precipitation of the asphaltic constituents and the
non hydrocarbon constituents. The precipitation is
followed by the agglomeration between the added asphalt
ones and the precipitating asphalt constituents. The
agglomerates, can be easily separated from the remaining
oil fractions, which is a disaffiliated oil Andre gas)
suited as feedstoc~s for further reining operations.
The precipitates separated can be further treated to
recover asphalts Andre asphaltenes~ The asphaltenes
recovered can ye partly recycled to the above contacting
step The contacting of a petroleum stock with an added
asphaltenes is normally carried out at temperatures not
higher than the boiling point of said stock, and the
precipitation ox the asp~altic constituents is usually
achieved at temperatures near the room temperature.
~2~g3~7
- 5
Therefore, heat can be exchanged between the contacting
apparatus and the precipitating (Rand separating appear-
tusk in order to save heat Furthermore, said precipi-
tales can ye treated by a paraffinic solvent to pro-
cipitate high-quality asphaltenes. The solvent used
can be recovered easily for recycling. Therefore, the
method requires no chemical, but fractions derived
from the feed stock.
Asphaltenes are the brown-to-black, pulverulent,
amorphous materials that are derived by treatment of
petroleums, residue, bituminous materials, etc. with
a light petroleum naphtha or solvent. Petroleum naphthas
range widely from the ordinary paraffinic straight-run
to the highly aromatic types On the basis of the
volubility in a variety of solvents, it has been
possible to distinguish among the various constituents
of petroleums Andre related materials as follows:
1) Carbides - Insoluble in carbon disulfide,
carbon tetrachloride, and low molecular
weight paraffins
2) Carbines - Soluble in carbon disulfide, but
insoluble in both carbon tetrachloride and
low molecular weight paraffins.
3) Asphaltenes - Soluble in both carbon disulfide
and carbon tetrachloride, but insoluble in low
molecular weight paraffins.
4) Militancy - Soluble in carbon disulfide, carbon
tetrachloride, and low molecular weight
paraffins
Most petroleums contain practically no carbides and
carbines, but residue from the cracking processes may
contain 2% by weight or more In the industry, the
separation of crude petroleums and bitumens into two
fractions, asphaltenes and militancy, is conveniently
brought about by means of low molecular weight paraffins,
which are known to have selective solvency for hydra-
carbons and simple low molecular weight hydrocarbon
~2~3:~7
derivatives. Petroleum naphthas of highly aromatic
types may dissolve asphaltenes partly, or completely
at high temperatures, and are therefore not recomb-
ended for treating asphaltenes or diluting asphaltenes
containing petroleum stocks in this invention, in order
to preserve the original characteristics of the asphalt
tones to be used for contacting. Pontoons, hotness
and hexanes are recommended for the above purpose.
Especially, n-pentane is known to precipitate asphaltenes
effectively without affecting their characteristics apple-
viably. This inventor has found that more asphaltenes
can be precipitated from asphaltenes containing petrol-
ems or related materials by using n-pentane as a delineate.
However, it still takes ~40 volumes of n-pentane to dilute
one volume of a crude oil in order to precipitate as
much as 90% by weigh of the asphaltenes contained in
said crude, my using 10% by weight of silica gel as
the precipitant. The same crude oil can be contacted
with the asphaltenes of the type identical to that con-
twined in Swede crude oil, in the amount equal to one half of the residue (cut point: 600F), to precipitate
nearly 100~ of the asphaltenes contained in said oil
without dilution by n-pentane.
It should be instructive to discuss further the
effect of the addition of asphaltenes into petroleums
or related materials. The hydrocarbons and their series
in petroleums and related materials are related closely,
and they differ from each other mainly in molecular
weight and HO ratio The close relations of the
various hydrocarbon series comprising the asphaltenes,
resins, and oils give rise to much overlapping of free-
lions into neighboring series, both in molecular weight
and HO ratio, although there is a large hydrogen
deficiency on the asphaltene hydrocarbons in which the
pronounced heterostructure appears. Excluding carbides
and carbines which may be contained in crude petroleums
only in negligible amounts, the asphaltenes are the final
,... .
I
condensation product High aromatic;`ty is generally
prevalent in the asphaltenes and in the series t Indeed,
the degree of aromaticity is of particular ;mportanee
when the resins associate with the asphaltene particles,
just as the degree of par affinity is important when the
resins dissociate The higher the aromaticity of resins
and of oils the wetter the solvency for asphaltenes, and
the solvent power of resins and of oils it one of the
most important facts in understanding the behavior of
the asphaltene/~altene interface, which characterize
the colloidal nature of crude petroleums and bitumens.
The same asphaltenes that disperse in a solvent of high
aromaticity may precipitate readily in a solvent of low
aromaticity~ Specifically, this inventor has found that
the colloidal stability of a petroleum, or of bitumen,
can be easily broken by changing the asphaltenes/resins
ratio of sand petroleum or of sand bitumen, or changing
the type of the asphaltenes or of the resins in same.
The degree of peptizat~on of the asphaltenes in a crude
2Q petroleum appears to ye affected strongly by the aroma-
Taoist, the metal constituents and the heteroatomic
constituents of the resins and the heavy aromatics in
said crude. For resins of equal aromaticity, those
having higher contents of metals and heteroatoms appear
to have greater peptizatton power for asphaltenes. It
appears that the resins associate with asphaltenes in
the manurer of an electron~donor-acceptor relation, and
furthermore, certain structural similarities between
the asphaltene molecules and the resin molecules in the
same crude could be playing an important role in deter-
mining -the colloidal behavior of said crude. This fact
has been experimentally observed by the inventor by
introducing asphaltenes obtained from one crude owl
into another crude oil of a different origin 9 and
observing the stability of toe newly formed asphaltenes .
oil dispersion system In every instance, asphaltenes
dispersed more readily in the crude oil from which whey
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~lZ293~7
-- 8
had been obtained, By increasing the amount of the
asphaltene$ added a point of immiscibility is reached
in the crude, at which the precipitation of asphaltenes
and resins begins to take place in the crude. This
finding has led the inventor to believe that for a given
petroleum at a siren temperature, there is a asphaltenes/
resins ratio at which the maximum amount of asphaltenes
can ye dispersed in said crude without precipitating out.
This ratio may be defined as the "asphaltenes/resins
salvation constant, or ratio", the knowledge of which
is useful in determining the optimum amount of asphaltenes
required in contacting and separating a given petroleum.
Furthermore, asphaltenes having higher H/C ratios can
disperse in oils easier than asphaltenes having low
H/C ratios. As the asphaltenes~resins ratio decreases
an addition of asphaltenes having high H/C ratios may
induce the formation of a gel, but an addition of
asphaltenes having low HO ratios would tend to precipi~
late Again, these facts can be explained in terms of
2Q the aromatic;ty of the asphaltenes and that of the
militancy in the petroleum
Extensive experimental evidences obtained by this
inventor indicate that asphaltenes in untreated crude
petroleums exist as single entities which are peptized
by the resin molecules and dispersed by the heavy
aromatic molecules in the crude. Asphaltenes in
bitumens appear to exist as clusters, and those in
residue usually exist as large agglomerations. There
is an experimental evidence that in untreated crude
petroleums, hydrogen bonding could be a preferential
intermolecular force acting between the resin molecules
and the asphaltene molecules. This may explain why
asphaltenes in crude petroleums are more difficult to
separate than those in residual Asphaltene molecules
which haze lost their peptizing resin molecules will
easily form clusters or agglomerates when they contact
due to their polarizabilities. Since both toe asphaltene
SLY
9 _
molecules and to resin molecules are very large, their
diffusion rates in petroleums would be extremely small
or negl~gi~le. Therefore, the conditions of agitation
and m;~x~ng on the contacting operation provided by the
present invention are extremely important The direct
intimate contact between the resins and the asphaltenes
is utmost important Individual asphaltene molecules
peptized my many resin molecules through hydrogen-bonding
form muzzles, whose structure is such that the bulk of
the substances with the greater molecular weight and
the most pronounced aromatic and polar nature are arranged
closest to the center (asphaltene molecule). These sub-
stances are again surrounded by lighter constituents of
less aromatic and polar nature until a gradual -transit-
lion to the intermiceller phase (oil is formed. Themetalic constituents and the heteroatomic constituents
appear to concentrate inside the Michelle than outside.
Therefore, the separation of the asphaltenes and the
resins from petroleums and/or related materials is the
key to the removal of the non hydrocarbon constituents
metals and heteroatomsl. The wreaking of the equal
brim at the asphaltene/resin interface by exceeding
the asphaltenes/resins salvation constant (or ratio)
discussed above us the key to the simple and effective
separation of petroleums Andre related materials, in
accordance to the principle of the present invention.
In the following, the present invention will be
discussed in detail by reference to the preferred,
basic processes of the invention shown in the accompany
in drawings FIGS. 1, 2 and 3, by reference to the
examples given in TABLES l and I
Brief Description of -the Drawings
The accompanying drawings illustrate the method
and apparatus of the present invention.
FIG 1 is a schematic representation showing a
preferred, basic process for roughening and partially
separating petroleums and related materials, in accord-
~Z293~
-- 10 7`
ante with the method provided by the invention.
FIG. 2 is a schematic representation of a preferred,
basic process for refining and partially separating
heavy crude petroleums, bitumens, residue, etc. in
accordance to the method provided by the invention.
FIG. 3 is a schematic representation of another
preferred, basic process for refining and partially
separating heavy crude petroleums, bitumens, residue,
etc., together Wylie the recovery of asphaltenes, in
accordance Thea the method provided by the invention.
.. ... ...
Detailed Description of the Invention
.. . . .. _ . .. . _ . .
The invention now will be described in detail, by
reference to the several specific embodiments shown in
the accompanying drawings, and to the results of export-
mental runs
As noted above, FIG. l illustrates, in block diagram, a preferred basic process for refining and
separating petroleums and related materials in accordance
to the method provided by the invention, which comprises:
I a contacting step, 2) a solid-liquid separating step,
I an asphaltenes precipitation step, 4) an asphaltenes
drying step and 5) a n-pentane recovering step. Refer
ring to FIG. l, the contacting apparatus 1 may be a
mixing tank, a fluidized-bed, etc. to provide the intimate
contacting between the feed stock and the added asphaltenes
and to facilitate the precipitation of the asphaltic con-
stituents and the non hydrocarbon constituents, together
with said added asphaltenes~ the solid rid separation
apparatus 2 may be a filter, a centrifuge, a liquid-
cyclone, etc. to effect the separation between the resultant precipitates and the oil constituents remain-
in the asphaltene precipitating apparatus 3 may be a
mixer-settler combination, a filtered etch to effect
the dilution of said precipitant with n-pentane and the
precipitation and the subsequent separation of asphaltenes
from said nwpentane7 the asphaltene drying apparatus 4 may
be a flash drum, a vacuum dryer, etc. to remove the
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33~L7
. 11
residual n-pentane from the precipitated asphaltenes
for final wrecker of asphaltenes? and the n-pentane
recovery apparatus 5 may be a flash still, an e~apora-
ion, eta to recover the n~pentane for recycling and
the res~ns-oil mixture for further processing. The
contacting step 1 and the solid-liquid separation step
2 are the basic steps, which can be carried out, if
desirable, in a single apparatus, such as a counter-
current mixer-settler, a contact filter, a rotary
filter using asphaltenes as the filter-aid, etc. In the
contacting apparatus 1, the feed stock is brought to
intimately contact with an added asphaltenes to effect
the precipitation of the asphaltic constituents and
the non hydrocarbon constituents together with said
added asphaltenes, and in the solid-liquid separating
apparatus 2, the mixture of solid masses precipitated
is effectively separated from the liquid (oil) medium
constituting the treated oil, which is suited as a
feed stock for catalytic cracking and for many further
refining operations. A part or whole, of said mixture
can be flashed to remove the residual volatile con-
stitu~nts and then stripped with steam to produce
high-qual~ty asphalts. Said mixture of solid masses
precipated is treated with n-pentane in -the asphaltene
precipitation apparatus 3 to precipitate the asphaltenes,
which are substantially free of resins, while the pro-
cipitated asphaltenes are dried in the asphaltene
drying apparatus 4 for removal of the residual n-pentane,
the spent n-pentane separated from the asphaltenes is
sent to the n-pentane recovery unit 5 for recovery and
recycling. A part of the asphaltenes recovered is
recycled to the contacting apparatus 1. The resins-oil
mixture from toe n-pentane recovery unit 5 may be used
as a eedstock for thermal cracking ox for resin recovery.
The method and apparatus for the contacting may
Mary widely, as noted aye. The contacting apparatus 1
in FIG. 1 should be, in general, equipped with a means
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~Z~3~7'
12 -
for agi-t~tin~ and mixing the masses in said apparatus.
Said means may include stirrer, aerator, vibrator, solid-
state mixture, sonic generator, etc. The contacting
apparatus 1 may be a fluidi~zed-bed of an added asphaltenes
and the petroleum being treated. When a filter-bed (or
packed-bed) is used to carry out both the contacting and
the subsequent sold liquid separation in the same appear-
tusk the periodical discharging of the resultant precipi~
tents accumulated will be necessary. however, a continue
out filter using asphaltenes as the filter-aid can be
employed to effect the continuous contaCtincJ and separating
of feed stocks. In this case, a layer of the precipitates
retained on the filter-cloth will junction like a filter-
bed to effect the contacting, the precipitation, and the
separation The continuous contacting combined with the
continuous solid-liqu;`d separation can be as effective,
if the fresh asphaltenes are continuously added to the
feed stream
Other solid-liquid contacting methods and apparatus,
I and various flow arrangements (counter-current, co-current,
cross-current, etc.) also can be employed, as may be
obvious to those who are skilled in the art. Needless to
say, there are numerous different methods and apparatus
for solid-liquid separation which can be employed in -the
I practice of this invention.
As noted above, FIG. 2 is a schematic representation
of a preferred basic process for refining and separating
heavy crude petroleums, bitumens, residue, etc., in
accordance with the method provided by the invention;
said process including the recovery of the solvent and
the asphalt. Referring to FIG 2, feed stocks are diluted
by a petroleum fraction (or fractions having a boiling
range not exceeding 6~0F, preferably, a liquid paraffinic
solvent (or sealants and intimately contacted by an
added asphaltenes in the contacting apparatus 1, which
may be a mixer-settler, a fluidized-bed, etc. to effect
the precipitation of the asphaltic constituents and the
~2zg3~7
- 13
nonhydrocarhon constituents, together with said added
asphaltenes. The mixture of solid masses precipitated
is then sent to the flashing (or drying apparatus I,
where the residual volatile constituents (mainly the
solvent added Gil said contacting apparatus) is removed
from sand mixture, which is treated in the stripper 3
to produce asphalt. The disaffiliated oil is separated
from the solvent by evaporation in the evaporator 4
and steam-stripped in the stripper 5. The solvent no-
covered in each of the four steps are combined and recycled to the contacting apparatus 1 as shown. By
the method of this invention using an added asphaltene
as the solid contractor, there is no need to use pique-
fled propane, or liquefied butane, to treat feed stocks
at high temperatures and high pressures. The treated
oil is suited as a feed stock for catalytic cracking and
for many other refining operations.
As noted above, FIG. 3 illustrates another pro-
furred embodiment of the basic process for rev nine
and separating heavy crude petroleums, bitumens, residue,
etc., in accordance with the method provided by the
invention; said process including the recovery of the
asphaltenes and the solvent, n-pentane. The process is
basically identical to the one shown in FIG. 2, except
that n-pentane is used as the solvent in order to prey
cipitate the asphaltenes, and that the treated oil con-
twining resins will not be suited as a feed stock for
catalytic cracking, but may be used in thermal cracking.
Referring to FIG 3 the contacting apparatus 1 may be
a mixer-settler, a fluidized~bed, etc., in which the
~eedstock is diluted with n~pentane and then intimately
contacted with an added asphaltene to effect the prows
citation of the asphaltenes contained and the nonhydro-
carbon constituents, together with said added asphaltenes.
us The total asphaltenes precipitated are then separated
from the oil fractions remaining, and then flashed and
dried in the flashing apparatus 2 to produce high-
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14 -
quality asphaltenes k which can be recycled or recovered
as a byproduct The oil fractions are separated in -the
evaporator 3 and in the stripper 4 to remove the n-
pontoon fox recycling The treated oil recovered will
contain resins, and is suited as a feed stock for thermal
cracking, or for resin wrecker. Needless to say, the
bottoms from the n-pentane recovery unit 5 in FIG. 1
and/or from the n-pentane recovery unit 5 in FIG. 3 can
be treated by a hydrocarbon solvent, preferably liquefied
propane, liquefied butane, or isobutane.
As may be obvious from the above discussion, in
treating heavy crude petroleums, bitumens, residue, etc.
the feed stock should be diluted with a suitable hydra-
carbon solvent (or solvents) before the contacting with
an added asphaltene~ The asphaltenes to be used for
the contacting with feed stocks are preferably treated by
n-pentane to dissolve the resins, while preserving the
original characteristics of said asphaltenes.
The conditions of the contacting operation are
very important-in achieving the objects of the operation.
Several important operational variables are summarized
below.
1. Temperature - The temperature of contacting
can affect the fluidity of the feed stock, the
hydron bonding between the asphaltenes and
the resins, the rates and the equilibria of
the redistribution of various constituents
near the asphaltene-resin interface and inside
the asphaltene-resins m~celles. The tempera-
lure in the contacting apparatus is normally
maintained above 60F, but not exceeding the
boiling point of the feed stock (or diluted
feed stock It has been found adequate to
heat crude petroleums at approximately 160F
for 10 to 30 minutes, and then cool it to
room temperature, at which the precipitation
of the asphaltic constituents takes place
I,,
~Z~3~7
- 15
more readily. The agglomeration of fine
precipitates is facilitated by gentle agile-
lion for a period of several minute before
the solid-liquid separation (filtration) may
be attempted
2. Pressure When no liquefied gas solvent is
employed the pressure will have no effect.
The method provided by the invention prefers
a liquid hydrocarbon solvent for diluting
lo feed stock as may be needed; and the contact-
in is normally carried out at thy atoms-
phonic pressure.
I Contacting time - The contacting time needed
depends on the nature of feed stock, the con-
tatting temperature, the dilution ratio, the
amount of asphaltenes added relative to the
amount of the asphaltic constituents in the
feed stock. Heavier feed stocks, lower con-
tatting temperatures, lower dilution ratios,
and small amounts of asphaltenes added
normally would require longer contacting time.
The method and apparatus of contacting also
will affect the contacting time required, as
may be obvious.
I Agitation - The intimate and uniform contact-
in between the feed stock and the added
asphaltenes can be achieved rapidly at a
higher temperature, if isotropic turbulence
is obtained. Once the asphaltene particles
and the resin particles have achieved the
intimate contacting, little or no agitation
is required for the precipitation of the
asphaltic constituents To facilitate the
agglomeration of all the precipitates, gentle
agitation is useful The above suggests that
a combination of a slurry-pump, a solid-state
mixer, and a vertically elongated, multi-
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16 -
stages tank equipped with a slow stirrer
would be an ideal contacting apparatus. The
feed stock the solvent (if used), and the
asphaltenes are fed -together to the slurry
pump which pumps the slurry formed through
a solid-state mixer to achieve the uniform
intimate contacting between the three before
entering said tank, where the precipitation
and the agglomeration can take place.
5. Slip velocity - If a packed-bed or a filter-
bed of asphaltenes is used, slower slip
velocities and longer residence time are
important in order to effect the precipita-
lion, the agglomeration, and the separation
of the asphaltic constituents while the
feed stock flows through said bed.
6. Viscosity - The viscosity of the ~eedstock
should be adjusted by heating or dilution
with a petroleum fraction (or fractions) to
facilitate the intimate contacting between
the asphalkenes and the resins and the
precipitation of the asphaltic constituents.
For ordinary crude petroleums, the dilution
would not be required if the contacting is
carried out at its boiling point, or about
160F.
7. Asphaltenas - As noted above the type and the
cleanness (free from resins and other heavy
aromatics) of the asphaltenes to be used for
the contacting operation are extremely
important. Preferably, they are identical,
in type, to those contained in the feed stock,
or similar types having high aromaticity and
lo HO ratio, and haze been treated by n
pontoon/ for the reasons already described
avow The n~pentane precipitated asphalt
tones are reasonably free from resins and
~.2Z93~
17
other heavy aromatics, and extremely effective
as the solid contractor to be used in the method
provided my the invention The amount of
asphaltenes required depends mostly on the
asphaltenes-resins salvation constant of the
feed stock, as already discussed above. The
asphaLtenes-resins solution constant (or
ratio) normally decreased as more paraffinic
solvent is added to the feed stock. While the
solvent molecules dissolve the resin molecules
and attempt to remove them away from thy pep-
tired asphaltene molecule, the effect of an
added asphaltene is to use the molecules of
the added asphaltenes to make hydrogen
bonding with these resin molecules and to
break the existing hydrogen bonds that they
make with the peptized asphaltene molecule.
It is important to note that the asphaltenes
to be used for contacting should not be
treated by a solvent which can dissolve said
asphaltenes, or change their characteristics,
especially their surface properties and
chemical structure. For example, cycle-
paraffins, aromatics, cyclohexane, pardon,
nitrobenzene, ethylene dichlorides chloroform,
carbon disulfide, carbon tetrachloride, etc.,
which can attack asphaltenes, should not be
used in diluting feed stocks or treating
asphaltenes Steam stripping, at a high
temperature, ox asphaltenes should be done
with a great care so that the asphaltenes
would not be badly oxidized or changed.
8. Solvent As already discussed above, hydra-
carbon solvents having lo aromaticity, low
polarity, and it HO ratio are on general
suited for use in diluting feed stocks.
Although low molecular weight paraffinic
I
18
solvents are preferred, in Yost cases a
petroleum fraction (or fractions containing
little ox no aromatics and having a boiling
range below 400F is adequate as a delineate
for most feed socks Petroleum fractions
having a bowling range as high as nearly
600F may also be used if they are mixed
with fractions having low boiling ranges,
and if the contacting is carried out at a
temperature above 160F.
There are a wide variety of solid-liquid swooper-
lion methods and apparatus, which can be applied to the
solid-liquid separation operation following the contact-
in operation in accordance with the method of the
invention. A few examples are: filtration (both batch
and continuous, centrifugation, liquid cyclone, settling,
etch The conditions for the separation will depend on
the nature of the feed stock and of the precipitates to
be separated. Filtration and centrifugation are usually
very effective liquid cyclone is not as effective; and
simple settling is too inefficient if the feed stock is
not diluted considerably
Thus, the simply method provided by the invention
can simultaneously remove the asphaltic, metallic, and
heteroatomic constituents rapidly from petroleums and/or
related materials It may include the recovery of
asphalts and of asphaltenes, without any operational
difficulties. The method can be modified through the
use of various additives, if desirable, thus enhancing
its effects and broadening its applicability. For
example, various solid sorbentsl, such as inorganic
metallic oxides (silica gel, alumina zealot, etc.),
clay minerals fullers earth, molecular sieves, etch
and organic solid sorbents, such as activated carbons,
charcoals, lignite coals etch can be used together
with asphaltenesr if desirable, as the contractors. In
the solid-liquid separation operation, filter-aids,
,. .
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~ZZ~93~7
such as diato~ceous earth, gypsum, etc. can be used to
facilitate the filtration of the precipitated asphaltic
constituents Polyvalent electrolytes which promote the
precipitation metallic halides which react with heavy
aromatics to form halides of the aromatics for easier
separation of resins and asphaltenes~ or acids which
react with asphaltenes and precipitate same from petrol-
ems also can be considered as additives. It should be
kept In mind that any foreign substances introduced to
a feed stock could become a source of the contamination
of the treated owls and of the products of the subsequent
refining processes. Furthermore, the complete separation
of these additives from the solid hydrocarbon constituents
(asphaltenes and resins) is usually extremely difficult
and costly. Therefore, the use of non hydrocarbon sub-
stances is not preferred in the method provided by the
invention .
The method of this invention may also be carried
out in conjunction with the conventional method, or
methods, in order to complement said conventional method.
However, for the reason described above, this approach
must be considered carefully in order to avoid the
possible operational difficulties and the contamination
problems
In order to illustrate specifically the practice
and the benefits of the present invention, the methods
descried in detail in connection with the accompanying
Figs 1 through 3 were followed in numerous experimental
runs conducted The results of some typical experimental
runs are shown in Tables 1 and 2; the former reporting
the results of experiments involving the treatment of
eleven (111 different crude petroleums; and the latter
reporting the results of experiments ;:nvol~ing the
treatment of four I different residual
Referring to TABLE 1, for each crude oil treated
and for each property measured, the first value listed
is that obtained before the treatment and the second
- SLY
value listed is that obtained after the treatment. The
properties determined are: the specific gravity at 60F,
the sulfur content by weigh-t percent I the nitrogen
content by weight percent (%1, the atmospheric residue
at cut point of 7Q0F, and the asphaltenes recovered by
weight percent to Because of the inevitable loss of
asphaltenes during the recovering process conducted in
the laboratory, the percent of the asphaltenes recovered
reported in TABLE 1 is smaller than the true value, and
the reproducibility of the data is probably about + 10%.
In carrying out each run, the crude in the amount of 2000
milliliters was added with the n-pentane precipitated
asphaltenes (previously recovered from the same crude
stock) in the amount equal to one half (1/2) of its
atmospheric residue (cut point: 700F), and then boiled
at about 160F for approximately 10 minutes. The slurry
was then allowed to cool to room temperature (about 70F)
prior to the filtration of said slurry through No. 4
Whitman filter paper to separate the entire precipitates.
Said precipitates separated were then treated with
n-pentane (10 volumes) to precipitate only the asphaltenes,
which were dried in vacuum at about 190F prior to the
weighing. The net amount of the asphaltenes produced,
which is the difference between the total asphaltenes
recovered and the asphaltenes added, was converted to
weight percent and reported in TABLE 1. Control runs
were made for each crude oil without adding the asphalt
tones, by following the some procedure No asphaltenes
could be separated in all of the control runs made.
As may be seen in TABLE 1, the contacting of these
crude oils with the added asphaltenes has resulted in
the reduction in specific gravity as much as nearly
6 percent (:%), in sulfur content over 8G percent (%~,
in nitrogen content over 80 percent (%~, in ash content
o'er 85 percent (%~, and in residue content nearly 95
percent ~%~. The weight of the asphaltenes separated
varied 11.2 to 35~5 percent (%~, depending on the crude
12Z93~7
. 21
TABLE 1. Treatment of Various Crude Petroleums
Specific Sulfur Nitrogen Ash Residue Asphal~enes
Gut- -Cbnbent Content Content Content Recovered
Cruxes ( - ) - (Wattage White) (Wt.%} (Whatnot I?
California Owe 0.51 0.398 0.0009 33.8 0
0.856 0.08 0.071 0.0001 1.4 20.6
. .............
_ .
California Owe 1.84 0.555 0.0035 41.9 0
LEA. 0.859 0.31 0.104 0.0Q04 2.8 29.1
.
Colorado 0.850 0.56 0.073 0.0004 26.5 0
RUB. 0.838 0.12 0.012 0.0000 1.2 17.5
- .
Ill mows 0.847 0.21 0.138 0.0005 28.3 0
L 0.831 0.03 0.033 0.0000 1.6 15.0
-
Kansas Owe 0.76 0.19 0.0021 43.6 0
R 0.851 0.11 0.03 0.0002 2.7 27.3
: .. .
Louisiana 0.846 0.21 0.040 0.0008 20.6 0
L 0.830 0.02 0.000 0.0000 1.1 11.2
. . . .. ..
Oklahoma Owe 1.68 0.4820.0022 55.9 0
G 0.864 0.29 0.0800.0003 2.6 35.5
Oklahoma 0~893 1.34 0.2430.0020 48.9 0
S 00848 0.24 0.0360.0003 3.1 30.7
... . . .. ..... ...
Texas 0.871 0.15 0.0200.0003 23.0 0
B 0.845 0.02 0.0000.0000 1.3 16.4
..... . ...
. _ _
Texas 0.863 2.12 0.000.0005 27.0 0
C 0.841 0.36 0.0Q00.00Q0 1.5 15~8
. . .. . . . .... .. ..... . ... .... . ... ... ... ..
. _ _ .
North 0.846 0~44 Q.21 0.0001 39.9 0
; yea 0.835 0.04 Q~02 0.0000 2.5 17.3
.. .. .. ... ... . .. . . - - -
_ . .
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~l2Z~3~f
22 -
oil treated. These results represent that the separation
of asphaltenes is over go percent I in most cases,
considering the fact that the reduction in residue us
over 95 percent C~2 in most cases
In TABLE 2, the results of experimental runs
involving the treatment of four I different still residue
from four (4) different crude owls are reported. Except
North Sea residue, which was a vacuum still residue with
1070F.cut point, the other three residue were atoms-
phonic still residue with 700F. cut point. Each residue
was treated in the three different ways: 1) contacting
with the asphaltenes; 2) contacting with silica gel;
and 3) contacting with a mixture of asphaltenes and
silica gel. In carrying out each run, the residue in
the amount of 200 milliliters was first diluted with
1200 milliliters of aromatic-free gasoline (boiling
range: 180 to 400QF.), and then boiled with one of the
solid contractors at approximately 160F~ for about 20
minutes. The amounts of the three solid contractors
employed were: I asphaltenes ~60 grams), 2) silica gel
(120 grams); and 3) asphaltenes-silica gel mixture in
1:1 ratio (100 grooms After boiling, the slurry was
allowed -to cool to room temperature (about 70F~), and
then filtered through No. 4 Whitman filter paper to
separate the entire precipitates. Said precipitates
separated were then treated by n-pentane (10 volumes)
to precipitate only top asphaltenes, which were dried
in vacuum at about 190F~ prior to the weighing. The
net amount of the asphaltenes produced which is the
difference between the total weight of the recovered
solids and the solid contractor added was converted to
weight percent and reported on TABLE 2. Control runs
were jade for each residue without adding a solid con-
tractor, by following the above procedure No asphaltenes
could be separated on all ox the control runs made.
The data given in TABLE 2 are the average values oboe
twined from several runs made for each residue. As
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23
TABLE I Recovery of ~sphaltenes from Various Residue.
........ ...
Solid Contacbors
Residue 1
~haltenes Silica Gel Asphaltenes~l ice None
. , , Gel
._ _ . . _
Texas 38.0% 11~2~ 21.3% 0%
, _ _
Oklahoma 41.2% 14.3% 22.5% o%
North 73~1% Z0~1% 41.1% 0%
. _
Monangas 71.4% 27~5% 42.0% I
. _ , .
may be seen from TALE 2, in every instance the result
of contacting by 60 grams of the asphaltenes is better
than that by 120 grams of the silica gel or that by 100
grams of the asphaltenes-silica gel mixture. The results
indicate also that the ability of the asphaltenes to
disaffiliate these residue is approximately 5 to 6 times
that of the silica gel used. The weight percent (based
on the residue) of the asphaltene separated in each case
is over 30 percent to), which may account for the near
complete separation of the asphaltenes contained in the
residue. It was extremely difficult to separate the
asphaltenes precipitated from the silica gel added
Therefore, it is not preferable to mix another solid con-
tractor with the asphaltenes in treating petroleums and/
or related materials by the method provided by the
invention.
In addition to those crude petroleums and residue
listed in Tables 1 and 2, many other crude petroleums,
bitumens, and residue haze been repined and separated
successfully, using various asphaltene doses, solvents,
and dilution ratios under various experimental Canada
lions, all in accordance to the method provided my the
invention Other experimental runs have been made,
using different methods of sold liquid contacting and
..
~22~93~L~
24
of solid-liquid separation In all cases, substantially
similar beneficial results were obtained.
It is obvious from the above illustrations and
discussion that petroleums and/or related materials
can be refined by removing the asphaltic, metallic,
and heteroatomic constituents by contacting same with
an added asphaltenes to effect the precipitation of said
constituents, and then separating the resultant precipi-
tales to recover the treated oil Andre gas containing
lo a substantially reduced concentration of said constituents,
in accordance with the method provided by the invention.
In carrying out said method, the fluidity of the feed-
stock to be treated should be adjusted, if necessary, by
heating or solvent dilution in order to facilitate the
contacting and the precipitation. Said added asphaltenes
are preferably the type identical to that contained in
the feed stock to be treated, or one having a lower H/C
ratio, and substantially free from resins and other
heavy aromatics. The optimum dose of said asphaltenes
to be added depends mainly on the nature of the feed-
stock to be treated. The method, apparatus, and opera-
tying conditions for said contacting and for said
separation of precipitates may vary widely as already
described above in detail. Furthermore, both said
contacting and said separation of precipitates can be
carried out in a single apparatus, such as a mixer-settler,
a filter-bed of asphaltenes, a continuous filter (using
asphaltenes as the filter aid), etc., if desirable.
The method provided by the invention may also be
carried out in conjunction with one of many conventional
methods, if the circumstance permits. Said method may
also be modified by the use of various additives
intended to affect the efficiency of said method although
the possible contamination, by said additives; of the
treated streams and the products from the subsequent
operations must be carefully considered.
The solvent (or solvents to ye used on diluting
. -I,,,
3~7
heavy feed stocks and in precipitating the asphaltenes to
be used for said contacting must be compatible with said
feed stocks and asphaltenes~ For diluting a petroleum
fraction or fractions having a boiling range not
exceeding 600F is preferable. For precipitating the
asphaltenes to be used as the contractor, n-pentane is
preferred, for the reason already described above.
It is obvious to those who are skilled in the art
that the recycling of the treated oil can be practiced
in the method provided by the invention, in order to
increase the final separation efficiency. In the alterna-
live, several units of the contacting and solid-liquid
separating apparatus can be connected in series and/or
parallel, in order to increase the capacity Andre the
separation efficiency of the process.
It should be understood that the present invention
applies to the refining and separation of all petroleums
and all petroleum-related materials, and, to the recovery
of asphalts and/or asphaltenes from said petroleums
Andre said materials, by contacting same with an added
asphaltenes, preferably the type identical to that
contained in said petrolelDms and/or said materials to
be treated, or one having lower HO ratio, to effect
the precipitation of the asphaltic, metallic, and
heteroatomic constituents, and then separating the
resultant precipitates from the treated oil (and/or gas)
containing a reduced concentration of said constituents.
Therefore, the intimate contacting between the feed stock
to be treated and said added asphaltenes, and the come
plate precipitation and subsequent separation of said constituents precipitated together with said added
asphaltenes are the keys to the method provided my
this invention
I'
