[0001] This invention relates to the processing of liquid hydrocarbons and, more particularly,
relates to the removal of insoluble material from liquid hydrocarbons.
[0002] Liquid hydrocarbons can include, for example, products derived from liquefaction
of a mixture of coal derived liquids or non coal derived liquids plus coal, with or
without a catalyst; or products derived from hydroprocessing of a mixture of coal
or non coal derived liquids, with or without a catalyst; or combinations thereof.
[0003] Although the following description of the process of the invention will proceed with
reference to the processing of products of liquefaction of carbonaceous material,
it will be understood that this description is exemplary only of the process of the
invention applied to the separation of solids from the above liquid hydrocarbons.
[0004] Liquid hydrocarbons can be classified into the basic components of oils, asphaltenes
and pre- asphaltenes. Insoluble solids may comprise one or more of mineral matter,
ash, spent catalyst and unreacted or undissolved carbonaceous residue. The oils are
soluble in hexane, the asphaltenes are insoluble in hexane and soluble in toluene
and the pre-asphaltenes are insoluble in toluene and soluble in tetrahydrofuran.
[0005] Reactor products from liquefaction of carbonaceous material, which is well known
in the art for conversion of solid carbonaceous material such as anthracite, bituminous
and sub-bituminous coal, lignite and peat, and other carbonaceous material to liquid
products are usually in the form of a slurry which contains oils, asphaltene, pre-
asphaltenes and insoluble solids.
[0006] Removal of insoluble solids from the products of coal liquefaction is desirable to
permit optimum recovery and processing of liquid hydrocarbons. The presence of insoluble
solids leads to difficulties in the subsequent downstream refining and upgrading of
liquid hydrocarbons. Separation of insoluble solids from the coal extract liquids
is difficult to effect due to the wide particle size range of the discrete insoluble
solids, the relatively high viscosity of the liquid phase even at high temperatures,
the small differences between the density of the liquid phase and the density of the
solids, and the inherent characteristics of the constituents of the coal liquefraction
products.
[0007] The separation of discrete mineral matter such as insoluble solids from the coal
extract liquids remains a continuing problem. Filtration provides for a high liquid
yield by means of washing with a light oil and subsequent recovery of the light oil
by drying of the filter cake and separation from the filtrate. A dried filter cake
contains typically by weight 5 to 10% liquid product. That is, the cake consists of
90 to 95% solids and 5 to 10% of the desired liquid product on a dried solids cake
basis. Filtration, although it provides a good liquid yield, still has as drawbacks:
slow filtration rates, cost of pre-coat materials, and handling of the filter cake.
Centrifuges do not achieve as sharp a separation of the solids as by filtration. Also,
mechanical problems arise in the continuous removal of solids due to their abrasive
and adhesive properties. A centrifuged 'solids cake' typically still contains 50 to
55% of liquid product on a total cake weight basis. Hydroclones achieve an even less
sharp separation and are at best used for pre-thickening purposes in combination with
other unit operations. Solvent extraction and leaching have been used for removal
of only part of the solids. Coarser and heavier particles need to be removed by other
means. Magnetic separation processes can only also remove part of the solids. The
organic compounds of coal are diamagnetic while the ash, i.e. inorganic mineral matter
compounds, are paramagnetic which makes it possible to separate these by magnetic
means. However, the unconverted coal cannot be separated. Shou J. K. P. and Collins
D. J. describe these problems in: "A Review of Solid-Liquid Separation Technology
in Coal Liquefaction Processes", Proceedings of the 28th Can. Chem. Eng. Conf., Publ.
by Can. Soc. for Chem. Eng., Ottawa, Canada, 1978.
[0008] Distillation or evaporation is a possible means of separation. Very sharp separation
can be achieved but liquid carry-over must be minimized. The bottoms of such units
typically comprise 55% liquid product and 45% solids, resulting in substantial liquid
losses. Coking is another process which provides a sharp separation. However, a considerable
amount of liquid product is lost due to gasification of the light oil fraction and
due to coking of the heavier liquid hydrocarbon products.
[0009] Anti-solvent deashing is a process whereby the solids are co-precipitated with some
of the asphaltene and pre-asphaltene portion of the liquid liquefaction product due
to the solution equilibrium imbalance brought about by the addition of an anti-solvent.
The precipitated solids phase typically comprises 55 to 60% liquid product. Examples
of such processes are described in U.S. Patents Nos. 3,790,467; 3,852,182; 3,856,675
and 4,180,456. U.S. Patent 3,790,467 is typical in disclosing the use of an anti-solvent
to precipitate from solution "Quasi- solid" materials to cause an increase in size
of smaller solids for enhanced separation using size as a separation parameter. Valuable
liquefaction product thus is lost or tied up with the solids fraction.
[0010] Critical solvent processes affect separation by the greatly enhanced dissolving power
of the solvent in the range of pressure and temperature near the critical values for
the solvent. Two processes that apply this property are described in U.S. Pat. Nos.
3,607,716 and 3,607,717. By proper choice of solvent, pressure and temperature, such
a process can effectively produce separate process streams enriched in solids, asphaltenes,
pre-asphaltenes, and oils. After recovery of the critical solvent by evaporation,
the solids phase typically still comprise 35 to 40% of the liquid product.
[0011] The asphaltenes and pre-asphaltenes are considered to be non-distillable in that
they "crack" into gaseous and liquid hydrocarbons and coke upon heating, with a poor
liquid recovery. If the asphaltenes and pre-asphaltenes are separated with the insoluble
solids from the oil by distillation, anti-solvent deashing or critical solvent deashing,
subsequent recovery of the asphaltenes and pre-asphaltenes as liquid product becomes
as best marginal. For low rank coals, these processes provide a low liquid yield.
[0012] According to the process of the present invention, mixtures of liquid hydrocarbons
and insoluble solids are contacted with a volatile solvent compatible with the oils,
asphaltenes and pre-asphaltenes for solubizing said oils, asphaltenes and pre-asphaltenes
as opposed to the above prior art processes in which the solvent functions as anti-solvent
or a critical solvent. The said liquid hydrocarbons and solids are contacted with
the volatile solvent in stages to form a carrier solution. The carrier solution is
displaced by the volatile solvent, preferably by a countercurrent or crosscurrent
contacting mode, to produce a slurry of insoluble solids with volatile solvent substantially
free of the said liquid hydrocarbons to permit a separation and removal of said insoluble
solids by gravity settling, preferably under centrifugal forces, such that a minimum
of interstitial liquid containing a minor amount of the liquid hydrocarbons is discharged
with the insoluble solids. The interstitial liquid, composed largely of the volatile
solvent, is substantially recovered from the solids by evaporation.
[0013] The liquid hydrocarbons, including substantially all the asphaltenes and pre-asphaltenes,
are thus effectively separated from the solids and can be in turn separated from the
volatile solvent for conventional processing. High losses of the asphaltenes and pre-asphaltenes
inherent in known processes, particularly for low rank coals such as lignite coals,
are avoided.
[0014] In its broad aspect, the process of the present invention for separating insoluble
solids from liquid hydrocarbons containing oils, asphaltenes and pre-asphaltenes comprises
the steps of: contacting the liquid hydrocarbons with a volatile solvent compatible
with the oils, asphaltenes and pre-asphaltenes to solubilize the said oils, asphaltenes
and pre-asphaltenes to form a carrier solution; separating insoluble solids from the
carrier solution by gravity separation and displacing said carrier solution from the
solids by volatile solvent whereby said insoluble solids are discharged with interstitial
volatile solvent; recovering said volatile solvent from the residual solids; and recovering
oils, asphaltenes and pre- asphaltenes substantially free of insoluble solids.
[0015] Gravity separation is applied, preferably by centrifugal forces which accelerate
the rate of separation, utilizing the density differences between the insoluble solids
and liquid phase. The volatile solvent is contacted with the liquid hydrocarbons in
an amount in the range of about 10 to about 250% by weight of the liquid hydrocarbons
preferably in countercurrent or cross- current stages applying centrifugal forces
to each stage whereby the final insoluble solids residue is compacted with a minimum
of interstitial liquid, said final interstitial liquid comprised largely of the volatile
solvent for ease of recovery.
[0016] Coal liquifaction products are particularly suited for the application of the process
of the invention with the use of a coal extract volatile solvent, said volatile solvent
normally being recovered for recycle. The coal liquefaction products are processed
for the asphaltene, pre-asphaltene and oils recovery and recycle of the volatile solvent.
[0017] The accompanying drawing is a simplified schematic flow diagram of the process of
the invention applied to the processing of coal liquefaction products, it being understood
that the scope of the invention is not to be limited thereby.
[0018] Referring now to the drawing, reactor products from coal liquefaction are mixed with
a compatible volatile coal extract solvent introduced by line 52 either in pre-mixer
10 or directly in separator 14. Contact of the reactor products with the solvent is
accomplished, preferably in a series of multiple-stage countercurrent or crosscurrent
mixers with the application of gravity separation such as by the use of centrifuges
at each stage, such that the solids residue in the final mixing and separating stage
is contacted with fresh volatile solvent for discharge of compacted solids residue
therefrom containing interstitially volatile solvent essentially free of coal liquefaction
products. The use of pre-mixer 10 assists in the solubilizing of the asphaltenes and
pre-asphaltenes by the volatile solvent. The multiple-stage contacting can be effected
in a single device having multiple internal stages.
[0019] The volatile coal extract solvent is recovered from subsequent processing to be described
and is compatible with the oils, asphaltenes and preasphaltenes. The volatile solvent
is prepared from a coal derived oil fraction having at least 80% by volume distillation
temperature between about 205° and 535°C for compatibility with the coal liquefaction
products. A typical volatile solvent, shown in Table 1, comprises by volume about
98.3% distillation temperature between about 205° to 515°C.
Distillation characteristics
[0020] The volatile coal extract solvent is contacted and mixed with the reactor products
in an amount by weight in the range of about 10 to about 250%, preferably about 20
to about 100%, of the coal liquefaction slurry product. The quantity employed will
vary according to the particular volatile solvent used and the characteristics of
the reactor products which are determined by the coal starting material and the manner
of liquefaction. Separator 14 is maintained at a temperature in the range of about
50° to 350°C under a pressure within the range of sub-atmospheric pressure to about
3.5 MPa.
[0021] Separation 14 is effected by gravity separation, in a conventional gravity settling
vessel or in a centrifuge with the application of multiplied settling forces, for
separation primarily according to differences in densities between the homogeneous
carrier solution comprised of solvent and liquefaction products and the insoluble
solids. The carrier solution is recovered as an overflow substantially free of solids
and the solids recovered as an underflow, the amount of underflow preferably being
kept to a minimum such as by the use of centrifugal forces to compact the solids and
to minimize the volume of interstitial carrier solution at each stage and to minimize
the amount of volatile solvent escaping with the solids at the last stage.
[0022] The underflow containing solids with interstitial carrier solution, mainly voltile
solvent, is withdrawn throuhg line 16 and fed to recovery unit 18, which may constitute
part of separator 14 or consist of a separate vessel in which the volatile solvent
is evaporated at a temperature within the solvent boiling range. The evaporated solvent
and any contained liquefaction product are fed by lines 22, 25 to series condensers
24, 26 with condensed product recycled to separator 40, to be described, by lines
28, 30, or discharged by line 32 as product.
[0023] The solids, substantially free of solvent, are withdrawn from unit 18 as dried, friable,
non- sticking solids which may be crushed and conveyed by line 20 to a gasifier or
burner. Separation of oil, asphaltenes and preasphaltenes in separator 14 from the
solids is substantially complete due to the effective separation of the liquefaction
products solubilized in the carrier solution and displaced by the volatile solvent,
substantially eliminating loss of coal liquefaction product with solids in line 20.
[0024] The overflow of carrier solution from separator 14 is fed through line 36 to separator
40 and mixed with a coal derived light oil which is incompatible with the asphaltene
and pre-asphaltene materials. The carrier solution and said light oil, such as light
naphtha, are processed in separator 40 at a temperature in the range of about 50°
to about 150°C at a pressure of from atmospheric pressure to about 3.5 MPa, the light
oil being introduced in an amount by weight in the range of about 30% to about 100%
of the carrier solution. The addition of the incompatible light oil precipitates a
substantial part of the asphaltenes and pre-asphaltenes in the form of an immiscible
liquid and/or solid phase having a greater density than the density of the carrier
solution from which they are precipitated.
[0025] The immiscible phases can be separated from each other by gravity settling, preferably
under centrifugal forces, to produce a non-visocus liquid overflow and a sticky semi-solid
underflow comprised mainly of asphaltenes and pre- asphaltenes. The underflow is withdrawn
by line 42 and is: returned to the liquefaction reactor, not shown, for further conversion
into lighter oils; discharged for use as a solids product-with a low ash content;
or upgraded such as by hydrocracking into distillable oils.
[0026] The liquid overflow from separator 40 is fed by line 44 to recovery unit 46 for stripping
and recovery of the light oil fraction by flash evaporation and fractionation, or
by distillation, for recycle by line 54 to separator 40. The bottoms are withdrawn
by line 48 and discharged as product through line 50 or recycled by line 52 to separator
14 or pre-mix vessel 10. The bottoms of vessel 46 may be passed through a hydroprocessor
49 to convert remaining asphaltene and pre-asphaltene fractions to distillated and
to increase the hydrogen concentration, i.e. to regenerate the volatile solvent. Replacement
of light oil taken from the system by removal of the two product streams 42, 50 can
be made up by coal extract oil from coal liquefaction through line 38.
[0027] The overflow of carrier solution from separator 14 may be directly fed to alternative
processing unit 58 instead of to separator 40. The unit depicted by numeral 58 may
be a hydrocracker from which the liquids are subsequently separated in a distillation
column into products, recycle oil for the slurrying of coal, and recycle volatile
coal extract solvent compatible with the asphaltenes and pre-asphaltenes; a distillation
column for separation of overflow by boiling range; or a solvent deasphalting process
such as a propane deasphalting process or Duosol process in which the asphaltenes
and pre- asphaltenes are separated from the solvent.
[0028] The process of the invention was carried out for the processing of reactor product
resulting from the direct liquefaction of lignite in separator 14 and recovery unit
18. Separator 14 was a batch centrifuge operated at 1500 G's at atmospheric pressure
with carrier solution maintained at 150°C. The reactor liquid product consisted of
86.49 mass units of liquid hydrocarbons and 13.51 mass units of unreacted coal and
ash. Contacting was carried out in a three-stage crosscurrent mode using a total of
205.34 mass units of volatile coal extract solvent. The last underflow was fed to
a vacuum flask for evaporation of the volatile solvent from the residual solids. Table
2 indicates the distribution of components in the feed to the separator, combined
separator overflow and final underflow and recovery unit overflow and bottoms. For
a feed to the separator of 86.49 mass units of reactor liquid product, 1.84 units
of reactor liquid product were lost with the insoluble solids in the recovery unit
bottoms, resulting in a recovery of 97.9% of the reactor liquid product.
1. A process for separating insoluble solids from liquid hydrocarbons containing oils,
asphaltenes, pre-asphaltenes, comprising the steps of:
contacting the liquid hydrocarbons with a volatile solvent compatible with the liquid
hydrocarbons to solubilize the liquid hydrocarbons and to form a carrier solution;
separating insoluble solids from the carrier solution by gravity separation and displacing
said carrier solution from the solids by volatile solvent whereby said insoluble solids
are discharged with interstitial volatile solvent;
recovering said volatile solvent from the insoluble solids; and
recovering said liquid hydrocarbons substantially free of insoluble solids.
2. A process for separating insoluble solids from liquid hydrocarbons containing oils,
asphaltenes and pre-asphaltenes comprising the steps of:
contacting and mixing the liquid hydrocarbons and insoluble solids with a volatile
solvent recoverable by evaporation which is soluble with the said oils, asphaltenes
and pre-asphaltenes throughout all the process steps;
separating the insoluble solids from the solution by gravity separation and displacement
of the asphaltenes and pre-asphaltenes from the solids by forming a compacted solids
phase with minimal residual liquid hydrocarbons in the interstitial spaces;
recovering oils, asphaltenes and pre- asphaltenes substantially free of insoluble
solids in a clarified liquid phase;
extracting residual asphaltenes and pre- asphaltenes in the compacted solids phase
by contacting and mixing said compacted solids phase with a volatile solvent and separating
the insoluble solids therefrom by gravity separation by forming a compacted solids
phase with minimal residual liquid hydrocarbons in the interstitial spaces until said
interstitial liquid hydrocarbon mixture in a final gravity separation is substantially
free of said asphaltenes and pre- asphaltenes;
and recovering said residual interstitial liquid hydrocarbon mixture from the insoluble
solids from the final separation by evaporation.
3. A process according to Claim 2 in which said insoluble solids are discharged with
insterstitial solvent substantially free of said asphaltenes and pre-asphaltenes.
4. A process according to Claim 2 or 3 in which volatile solvent is recovered from
said oils, asphaltenes and pre-asphaltenes.
5. A process according to Claim 1 or 4 in which said liquid hydrocarbons are products
of coal liquefaction and said volatile solvent is a coal extract.
6. A process according to any preceding claim applying said gravity separation in
a centrifuge whereby said insoluble solids are compacted to minimize the volume of
interstitial carrier solution or volatile solvent.
7. A process according to Claim 4, 5 or 6 in which said volatile solvent is added
in an amount by weight in the range of about 10 to 250% of the liquid hydrocarbons.
8. A process according to any of Claims 1 to 5 in which the liquid hydrocarbons are
contacted with the volatile solvent in a pre-mixer prior to the gravity separation
for a time sufficient to effect substantial solubilization of the liquid hydrocarbons.
9. A process according to any of Claims 1 to 5 in which the liquid hydrocarbons are
contacted with the volatile solvent in a single stage or a multistage cross-current
or countercurrent system.
10. A process according to any of Claims 1 to 5 in which the gravity separation is
effected under centrifugal forces sequentially with addition and mixing of the volatile
solvent with the liquid hydrocarbons, said volatile solvent being added in an amount
by weight in the range of 10 to 250% by weight of the liquid hydrocarbons crosscurrent
or countercurrent to the flow of liquid hydrocarbons whereby the insoluble solids
in a final mixing and separating stage is contacted with fresh volatile solvent for
discharge of compacted insoluble solids containing interstitially volatile solvent
essentially free of said liquid hydrocarbon.
11. A process according to any of Claims 1 to 5 in which the gravity separation is
conducted at a temperature in the range of about 50° to 350°C at a pressure in the
range of sub-atmospheric pressure to about 3.5 MPa.
12. A process according to CLaim 4, 5 or 6 in which at least 80% by volume of the
volatile solvent has a distillation temperature in the range of 205° to 535° C.
13. A process according to any of Claims 1 to 12 in which the substantially solids-free
carrier solution recovered from the gravity separation is fed to one of a hydrocracker
from which the liquids are separated in a distillation column into products, recycle
oil for slurrying of coal and recycle solvent compatible with the asphaltenes and
pre-asphaltenes; a distillation column for separation of said overflow by boiling
range; or a solvent deasphalting process in which the asphaltenes and pre-asphaltenes
are separated from the solvent.
14. A process according to any of Claims 1 to 5 in which the substantially solids-free
carrier solution recovered from the gravity separation is contacted with a light oil
incompatible with the asphaltenes and pre-asphaltenes in an amount sufficient to precipitate
a portion of said asphaltenes and pre-asphaltenes, separating said precipitated asphaltenes
and pre-asphaltenes from the liquid phase, and recovering the light oil for recycle
to the substantially solids-free carrier solution.
15. A process according to any of the preceding claims in which the recovered asphaltenes
and pre-asphaltenes substantially free of insoluble solids are converted by hydrocracking
to distillates.
16. A process according to any of the preceding claims in which the liquid hydrocarbons
are at least one of:
products derived from liquefaction of a mixture of coal-derived liquids plus coal;
products derived from the liquefaction of non coal-derived liquids plus coal; products
derived from hydroprocessing of a mixture of coal-derived liquids; products derived
from the hydroprocessing of non coal-derived liquids; said products derived with a
catalyst; and combinations thereof.
17. A process according to any of Claims 1 to 5 in which part of the carrier solution
from which the light oil and most of the asphaltenes and pre-asphaltenes have been
separated is fed to a hydroprocessor to regenerate the volatile solvent.
1. Verfahren zur Abtrennung unlöslicher Feststoffe aus Öle, Asphaltene und Pre-Asphaltene
enthaltenden flüssigen Kohlenwasserstoffen, umfassend die folgenden Schritte:
In-Berührung-Bringen der flüssigen Kohlenwasserstoffe mit eninem flüchtigen, mit den
flüssigen Kohlenwasserstoffen verträglichen Lösungsmittel, um die flüssigen Kohlenwasserstoffe
löslich zu machen und eine Träger-Lösung zu bilden;
Abtrennen der unlöslichen Feststoffe von der Träger-Lösung durch Schweretrennung und
Verdrängen der Träger-Lösung von den Feststoffen durch flüchtiges Lösungsmittel, wodurch
die unlöslichen Feststoffe mit eingelagertem flüchtigem Lösungsmittel ausgetragen
werden;
Rückgewinnen des flüchtigen Lösungsmittels von den unlöslichen Feststoffen; und
Gewinnen der von unlöslichen Feststoffen im wesentlichen freien flüssigen Kohlenwasserstoffe.
2. Verfahren zur Abtrennung unlöslicher Feststoffe aus Öle, Asphaltene und Asphalten-Vorstufen
(Pre-Asphaltene) enthaltenden flüssigen Kohlenwasserstoffen, umfassend die folgenden
Schritte:
In-Berührung-Bringen und Vermischen der flüssigen Kohlenwasserstoffe und unlöslichen
Feststoffe mit einem durch Abdampfen rückgewinnbaren flüchtigen Lösungsmittel. ssigen
Kohlenwasserstoff-Gemisch, das mit den Ölen, Asphaltenen und Pre-Asphaltenen in sämtlichen
Verfahrensschritten löslich ist;
Abtrennen der unlöslichen Feststoffe von der Lösung durch Schweretrennung und Verdrängen
der Asphaltene und Pre-Asphaltene von den Feststoffen durch Bildung einer verdichteten
Feststoff-Phase, in der flüssige Kohlenwasserstoff-Reste in den Zwischenräumen nur
in minimaler Menge zurückbleiben;
Gewinnen der von unlöslichen Festoffen im wesentlichen freien Öle, Asphaltene und
Pre-Asphaltene in einer geklärten flüssigen Phase;
Extrahieren der restlichen Asphaltene und Pre-Asphaltene in der verdichtenten Feststoff-Phase
durch In-Berührung-Bringen und Vermischen der verdichteten Feststoff-Phase mit einem
flüchtigen Lösungsmittel und Abtrennen der unlöslichen Feststoffe daraus durch Schweretrennung
unter Bildung einer verdichteten Feststoff-Phase, in der flüssige Kohlenwasserstoff-Reste
in den Zwischenräumen nur in minimaler Menge zurückbleiben, bis das flüssige Kohlenwasserstoff-Gemisch
in den Zwischenräumen in einer letzten Schweretrennung im wesentlichen frei von Asphaltenen
und Pre-Asphaltenen ist; und
. Rückgewinnen des flüssigen Kohlenwasserstoff - Gemischs aus den Zwischenräumen der
unlöslichen Feststoffe der letzten Trennung durch Abdampfen.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß die unlölichen Feststoffe
mit in den Zwischenräumen befindlichem Lösungsmittel im wesentlichen frei von den
Asphaltenen und Pre-Asphaltenen ausgetragen werden.
4. Verfahren nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß das flüchtige Lösungsmittel
von den Ölen, Asphaltenen und Pre-Asphaltenen zurückgewonnen wird.
5. Verfahren nach Anspruch 1 oder 4, dadurch gekennzeichnet, daß die flüssigen Lohlenwasserstoffe
Produkte der Kohleverflüssigung sind und das flüchtige Lösungsmittel ein Kohle-Extrakt
ist.
6. Verfahren nach irgendeinem der vorhergehenden Ansprüche, dadurch gekennzeichnet,
daß die Schweretrennung in einer Zentrifuge durchgeführt wird, wodurch die unlöslichen
Feststoffe verdichtet werden, um das Volumen der Träger-Lösung oder des flüchtigen
Lösungesmittels in den Zwischenräumen auf ein Minimum zu verkleinern.
7. Verfahren nach Anspruch 4, 5 oder 6, dadurch gekennzeichnet, daß das flüchtige
Lösungsmittel in einer Menge im Bereich von 10 bis 250 Gew.%, bezogen auf die flüssigen
Kohlenwasserstoffe, zugesetzt wird.
8. Verfahren nach irgendeinem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die
flüssigen Kohlenwasserstoffe mit dem flüchtigen Lösungsmittel in einem Vormischer
vor der Schweretrennung eine Zeitspanne in Berührung gebracht werden, die ausreicht,
um die flüssigen Kohlenwasserstoffe im wesentlichen löslich zu machen.
9. Verfahren nach irgendeinem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die
flüssigen Kohlenwasserstoffe mit dem flüchtigen Lösungsmittel in einem einstufigen
oder mehrstufigen Kreuzstrom- oder Gegenstrom-System in Berührung gebracht werden.
10. Verfahren nach irgendeinem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß
die Schweretrennung unter Zentrifugalkräften sequentiell mit zugabe und Vermischen
des flüchtigen Lösungsmittels mit den flüssigen Kohlenwasserstoffen durchgeführt wird,
wobei das flüchtige Lösungsmittel in einer Menge im Bereich von 10 bis 250 Gew.-%,
bezogen auf die flüssigen Kohlenwasserstoffe, im Kreuzstrom oder Gegenstrom zu dem
Strom der flüssigen Kohlenwasserstoffe, zugesetzt wird, wodurch die unlöslichen Feststoffe
in einer letzten Stufe des Mischens und Abtrennens mit frischem Lösungsmittel in Berührung
gebracht werden, wodurch verdichtete unlösliche Feststoffe ausgetragen werden, die
in den Zwischenräumen von flüssigen Kohlenwasserstoffen im wesentlichen freies flüchtiges
Lösungsmittel enthalten.
11. Verfahren nach irgendeinem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß
die Schweretrennung bei einer Temperatur im Bereich von etwa 50°C bis 350°C unter
einem Druck im Bereich von unterhalb des Atmosphärendrucks bis etwa 3,5 MPa durchgeführt
wird.
12. Verfahren nach Anspruch 4, 5 oder 6, dadurch gekennzeichnet, daß wenigstens 80
Vol.- % des flüchtigen Lösungsmittels eine Destillationstemperatur im Bereich von
205°C bis 535°C aufweist.
13. Verfahren nach irgendeinem der Ansprüche 1 bis 12, dadurch gekennzeichnet, daß
die bei der Schweretrennung gewonnene, im wesentlichen feststoffreie Träger-Lösung
eingeleitet wird in eine der folgenden Verfahrensstufen:
einen Hydrocracker, aus dem die Flüssigkeiten in einer Destillationskolonne in Produkte,
Rücklauf-Öl zum Aufschlämmen der Kohle und mit den Asphaltenen und Pre-Asphaltenen
veträgliches Rücklauf-Lösungsmittel aufgetrennt werden;
eine Destillationskolonne zum Trennen des Überlaufs vermittels des Siedebereichs;
oder
ein Lösungsmittel-Entasphaltierungs-Verfahren, in dem die Asphaltene und Pre-Asphaltene
von dem Lösungsmittel getrennt werden.
14. Verfahren nach irgendeinem der Asprüche 1 bis 5, dadurch gekennzeichnet, daß die
bei der Schweretrennung gewonnene, im wesentlichen feststoffreie Träger-Lösung mit
einem mit den Asphaltenen und Pre-Asphaltenen unverträglichen Leichtöl in solcher
Menge in Berührung gebracht wird, die zur Asfällung eines Teils der Asphaltene une
Pre-Asphaltene ausreicht, wobei die abgeschiedenen Asphaltene und Pre-Asphaltene von
der flüssigen Phase abgetrennt werden und das Leichtöl zur Ruckführung zu der im wesentlichen
feststoffreien Träger-Lösung zurückgewonnen wird.
15. Verfahren nach irgendeinem der vorhergehenden Ansprüche, dadurch gekennzeichnet,
daß die gewonnenen Asphaltene und Pre-Asphaltene, die im wessentlichen frei von Feststoffen
sind, durch Hydrocracken in Destillate umgewandelt werden.
16. Verfahren nach irgendeinem der vorhergehenden Ansprüche, dadurch gekennzeichnet,
daß die flüssigen Kohlenwasserstoffe aus wenigstens einem der folgenden Materialien
bestehen:
Produkte, die aus der Verflüssigung einer Mischung aus von Kohle herrührenden Flüssigkeiten
plus Kohle stammen;
Produkte, die aus der Verflüssigung einer Mischung aus nicht von Kohle herrührenden
Flüssigkeiten plus Kohle stammen;
Produkte, die aus der Hydrierverarbeitung eines Gemischs von Kohle herrührender Flüssigkeiten
stammen;
Produkte, die aus der Hydrierverarbeitung nicht von Kohle herrührender Flüssigkeiten
stammen;
der gennanten Produkte, die mit Hilfe von Katalysatoren erhalten wurden; und
Kombinationen der vorstehenden.
17. Verfahren nach irgendeinem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß
ein Teil Träger-Lösung, aus der das Leichtöl und der größte Teil der Asphaltene und
Pre-asphaltene abgetrennt worden sind, zur Rückgewinnung des flüchtigen Lösungsmittels
einer Anlage für die Hydrierverarbeitung zugeführt werden.
1. Procède pour la séparation de matières solides insolubles à partir d'hydrocarbures
liquides, contenant des huiles, des asphaltènes et des pré-asphaltènes, comprenant
les étapes suivantes:
mise en contact des hydrocarbures liquides avec un solvant volatil compatible avec
les hydrocarbures pour solubiliser les hydrocarbures liquides et former une solution
mère;
séparation des matières solides insolubles à partir de la solution mère par décantation
et déplacement de ladite solution mère des matières solides par addition de solvant
volatil, lesdites matières solides insolubles étant transférées avec le solvant volatif
interstitiel;
récupération dudit solvant volatil à partir des matières solides insolubles; et
récupération desdits hydrocarbures liquides pratiquement exempts de matière solide
insoluble.
2. Procédé pour la séparation de matières solides insolubles à partir d'hydrocarbures
liquides contenant des huiles, des asphaltènes et des pré-asphaltènes, caractérisé
ce qu'il comprend les étapes suivantes:
mise en contact et mélange des hydrocarbures liquides et des matières solides insolubles
avec un mélange d'hydrocarbures liquides prétraité récupérable par évaporation, lequel
est soluble avec lesdites huiles, asphaltènes et pré-asphaltènes dans toutes les étapes
du procédé;
séparation des matières solides insolubles à partir de la solution par décantation
et déplacement des asphaltènes et pré-asphaltènes des matières solubles en formant
une phase solide compacte avec le minimum d'hydrocarbures liquides résiduels dans
les espaces interstitiels;
récupération des huiles, asphaltènes et pré-asphaltènes pratiquement exempts de matière
solide insoluble en une phase liquide transparente;
extraction des asphaltènes et pré-asphaltèmes résiduels dans la phase solide compacte
par contact et mélange de ladite phase solide compacte avec un solvant volatil et
séparation des matières solides insolubles obtenues par décantation en formant une
phase solide compacte avec le minimum d'hydrocarbures liquides résiduels dans les
espaces interstitiels jusqu'à ce que ledit mélange d'hydrocarbures liquides interstitiels
dans la décantation final soit pratiquement exempt desdits asphaltènes et pré-asphaltènes;
et
récupération dudit mélange d'hydrocarbures liquides interstitiels résiduels à partir
de matières solides insolubles de la séparation finale par évaporation.
3. Procédé selon la revendication 2, dans lequel lesdites matières solides insolubles
sont transférées avec le solvant interstitiel pratiquement exempt desdits asphaltènes
et pré-asphaltènes.
4. Procédé selon l'une des revendications 2 ou 3, dans lequel le solvant volatil est
récupéré à partir desdites huiles, asphaltènes et pré-asphaltènes.
5. Procédé selon l'une des revendications 1 à 4, dans lequel lesdits hydrocarbures
liquides sont des produits de la liquéfaction du charbon et ledit solvant volatil
est un extrait de charbon.
6. Procédé selon l'une quelconque des revendications précédentes appliquant ladite
décantation dans une centrifugeuse où lesdites matières solides insolubles sont comprimées
pour réduire au minimum le volume de solution mère interstitielle ou de solvant volatil.
7. Procédé selon les revendications 4, 5 ou 6, dans lequel ledit solvant volatil est
ajouté en une quantité en poids de 10 à 250% des hydrocarbures liquides.
8. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel les hydrocarbures
liquides sont mis en contact avec le solvant volatil dans un prémélangeur avant la
décantation et pendant une durée suffisante pour réaliser une solubilisation importante
des hydrocarbures liquides.
9. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel les hydrocarbures
liquides sont mis en contact avec le solvant volatil dans un dispositif à un seul
étage ou à plusieurs étages, à courant croisé ou à contre-courant.
10. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la décantation
est mise en oeuvre sous l'action de forces centrifuges de façon séquentielle avec
addition et mélange du solvant volatil et des hydrocarbures liquides, ledit solvant
volatil étant ajouté en une quantité en poids dans l'intervalle de 10 à 250% hydrocarbures
liquides, suivant un courant croisé ou à contre-courant du courant des hydrocarbures
liquides où les matières solides insolubles dans un mélange final et à l'étage de
séparation sont mises en contact avec le solvant volatil frais pour transfert des
matières solides insolubles compactes contenant le solvant volatil interstitiel pratiquement
exempt dudit hydrocarbure liquide.
11. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la décantation
est mise en oeuvre à une température d'environ 50 à 350°C, à une pression comprise
entre la pression subatmosphérique et environ 3,5 MPa.
12. Procédé seolon la revendication 4, 5 ou 6, dans lequel au moins 80% en volume
du solvant volatil a une température de distillation allant de 205 à 535°C.
13. Procédé selon l'une quelconque des revendications 1 à 12, dans lequel la solution
mère pratiquement exempte de matières solides récupérée à partir de la décantation
est introduite dans un hydrocraqueur à la sortie duquel les liquides sont séparés
dans une colonne de distillation en produits, huile recyclée pour délayer le charbon
et solvant recyclé compatible avec les asphaltènes et pré-asphaltènes; une colonne
de distillation pour la séparation dudit surnageant par gamme d'ébullition; ou un
procédé de déasphaltage par solvant dans lequel des asphaltènes et pré-asphaltènes
sont séparés du solvant.
14. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la solution
mère pratiquement exempte de matières solides récupérée à partir de la décantation
est mise en contact avec une huile légère incompatible avec les asphaltènes et pré-asphaltènes
en quantité suffisante pour précipiter une fraction desdits asphaltènes et pré-asphaltènes,
avec séparation desdits asphaltènes et pré-asphaltèmes précipités à partir de la phase
liquide, et récupération de l'huile légère pour recyclage vers la solution mère pratiquement
exempt de matières solides.
15. Procédé selon l'une des revendications précédentes, dans lequel les asphaltènes
et pré-asphaltènes récupérés, pratiquement exempts dé matières solides insolubles
sont transformés par hydrocraquage en distillats.
16. Procédé selon l'une quelconque des revendications précédentes, dans lequel les
hydrocarbures liquides sont au moins choisis parmi:
les produits dérivés de la liquéfaction d'un mélange de liquides dérivés du charbon
plus du charbon; les produits dérivés de la liquéfaction de liquides ne dérivant pas
du charbon plus du charbon; les produits dérivés du traitement hydrothermique d'un
mélange de liquides dérivés du charbon; les produits dérivés du traitement hydrothermique
de liquides ne dérivant pas du charbon; lesdits produits dérivés avec un catalyseur;
et leurs combinaisons.
17. Procédé selon t'une des revendications 1 à 5, dans lequel une partie de la solution
mère dont on a séparé l'huile légère et la majeure partie des asphaltènes et pré-asphaltènes,
est introduite dans un hydro-processeur pour régénérer le solvant volatil.