FR2462469A1 - Recovering premium oil from slurry produced by hydrogenation of coal - by countercurrent contact with a non-polar solvent in a column - Google Patents

Abstract

A feed slurry produced from a solid carbonaceous fuel (esp. coal) is sepd. into a premium liq. oil fraction (I) and fire solids and polar liquids -contg. fraction (II) by contact with a non-polar liq. solvent, chosen from (a) 5-9C alicyclic hydrocarbons, (b) 5-9C aliphatic hydrocarbons and (c) a naphthenic or paraffinic fraction of a coal liquefaction prod. contg. 10wt.% aromatic cpds. in a vertical column having a lower collection zone whose wall temp. is >=20 degrees C higher than that of the wall defining a contacting zone. The column has an upper setting zone which, along with the contacting zone, is operated at 100-250 degrees C and at a pressure sufficient to keep the feed and the solven liq. but 450 psi. The feed is introduced at the top and the solvent at the bottom of the contacting zone, the solvent:feed wt. ratio being >=0.5:1 (pref. 0.6-5:1). The solvent passes up the column, the feed passing down, and is in intimate contact with the feed and extracts (I) from it. (I) is then recovered as an overflow from the settling zone and (II) is recovered as a viscous slurry underflow from the collection zone. A solids-free overflow of premium oil is recovered from the column. Unconverter fuel, polar molecules rich in heteroatoms (O, N, S) etc. are also removed.

Description

 The present invention relates to a method for separating a slurry comprising finely divided solids, polar liquids and a high quality oil, this sludge being produced by high temperature hydrogenation of a solid hydrocarbon fuel, so as to obtain, by this separation a first fraction comprising the upper oil and a second fraction comprising finely divided solids and polar liquids.

 The high temperature hydrogenation of solid hydrocarbon fuels, as used in the coal liquefaction process, has the effect of producing a feedstock slurry and comprising not only a high quality liquid oil, but also various solids, for example ashes, inorganic sulfur and other liquids, for example polar liquids.

The separation of these substances, particularly finely divided solids, and the higher oil, or the removal of said substances, is a major problem which has been the subject of much research.

 British Pat. No. 312,657 discloses an apparatus and a process for separating, from solid residues, oils obtained in the destructive hydrogenation of varieties of coals, tars, mineral oils and the like.

The apparatus comprises a vertical column provided with a clarification vessel attached to the top of said column, and a worm attached to the bottom thereof. The process involves introducing a slurry of solid residues and oils into, at or near the column, and introducing a solvent, typically benzene, into said column. by the bottom thereof or in its vicinity, so that going up in the column, the solvent extracts the oils from the sludge flowing in said column. The solid residues are removed in the form of a powder from the bottom of the column by the worm, while the oils are removed at the top of the column as a head flow from the clarification vessel. .

 U.S. Patent Nos. 3,611,716 and 3,607,717, in the name of Kerr-McGee, disclose a gravity settling process comprising removal from a coal liquefaction product, finely divided solids, using a solvent heated to a supercritical temperature.

This method differs from the others in that the solids settle in a dense phase gas (the solvent being in super-critical conditions). The finely divided solids are contained in the extraction residue.

 In accordance with the present invention, there is now provided an improved process for separating a sludge feedstock produced by high temperature hydrogenation of a solid hydrocarbon fuel and comprising finely divided solids, polar liquids and a high quality liquid oil, at a higher temperature. first fraction comprising said upper liquid oil and a second fraction comprising said finely divided solids and said polar liquids, characterized in that t (a) mixing the sludge feed with a non-polar liquid solvent which consists of an aliphatic hydrocarbon or C 5 -C 8 alicyclic or a naphthenic or paraffinic fraction of a coal liquefaction product containing less than 10% by weight of aromatic compounds, the mixture being made in a vertical column comprising a clarification zone, a contact zone and a zone collector, areas of clarification and contact f operating at a temperature between 1000C and 2500C and under a pressure sufficient to maintain plowing and solvent in the liquid state, but less than 31.7 bars, the sludge being introduced into the column at the top of the contact zone or its vicinity, while the solvent is introduced into the column from the bottom of the contact zone or in its vicinity, the solvent and the sludge being mixed in a weight ratio of at least 0.5 / 1 and brought into contact so that the solvent (1) passes up the column while the slurry passes through the descent column (2) is in intimate contact with the sludge as the solvent and the slurry pass through the column simultaneously; and (3) extracts the upper liquid oil from the sludge as the solvent and the slurry pass through the column simultaneously; (b) recovering the first fraction from the column clarifying zone as overflow or teat flow; and (c) the second fraction is drawn from the collector zone of the column in the form of a base flow consisting of a viscous sludge.

 The method of the invention thus described has the effect of producing an overhead flow consisting of upper oil substantially free of solids and a base flow containing a minimum amount of higher oil. In addition, this process has the effect of eliminating other substances, such as polar molecules of unconverted fuels, rich in hetero atoms (O, N, S).

 The sludge used in the context of the invention is a sludge generally produced by high temperature hydrogenation of any solid hydrocarbon fuel. The sludge produced by the liquefaction of coal is given for illustrative purposes. The solid fraction of this sludge comprises finely divided solids (eg ashes), inorganic sulfur (e.g., pyrrhotite) and organic solid materials (e.g. unreacted coal) while that the liquid fraction comprises a higher oil (eg, hydroxide-soluble sludge constituents, such as paraffinic, naphthenic and aromatic hydrocarbons), and polar liquids (eg, asphaltenes and insoluble products); toluene, both defined below). The term "finely divided" used in the context of the invention applies to mid-size solid particles having a size of about 0.1 to 20 microns. The solids content (by weight) of said sludge can vary widely, but depends at least partly on the polar liquid content. Generally, the solids content, which can be effectively treated, is even greater than the amount of polar liquids present is important.

Specifically, a sufficient amount of polar liquids must be insoluble in the non-polar solvent under the conditions prevailing in the column, so that the polar liquids combine to form a separate continuous liquid phase in which the amount of finely divided sol can to be dispersed. Although the quantitative parameters can effectively vary with the sludge used as the feedstock, the conditions prevailing in the column, the solvent and other factors, it can be said that, in general, the resulting flow It is preferred to use a slurry having a solids content of less than about 25 weight percent, with particular preference being given to a slurry having a lower solids content. at about 20% by weight.

 In a specific embodiment of the invention, in which hexane is the non-polar solvent used, it is produced by the liquefaction of a bituminous coal, a sludge, which is particularly suitable. This sludge can take several forms: it can be, for example, the sludge as produced (ash content of about 3 to 8% by weight), the sludge after the elimination, for example by centrifugation, of a certain amount of solids (ash content of about 0.5 to 5% by weight) or sludge after a solids concentration technique, for example, as a stream from a hydrocyclone (ash content of about 1015% by weight). The solids content of each of these forms is less than about 25% by weight of the slurry.

 The principle considerations to be observed in the choice of the solvent are that the solvent selectively extracts the higher oil and that the solvent and the higher oil (extracted) do not have a clear superposition of their distillation intervals (because such a superposition can result in contamination by interaction). Since the constituents of the upper oil are generally non-polar, a non-polar solvent is used. The solvents are preferably hydrocarbons and most preferably aliphatic or alicyclic C 5 -C 8 hydrocarbons, such as pentane, hexane, heptane, octane, 3-methylpentane, cyclopentane, cyclohexane, and the like. Other suitable solvents include certain naphthenic or paraffinic fractions of a coal liquefaction product, such as a C4-C5 mixture or a paraffinic petroleum fraction, these fractions containing less than about 10% by weight of aromatic compounds.

 The conditions (temperature and pressure) prevailing in the column can effectively vary with the solvent and the composition of the sludge charge. It is necessary to use a minimum column temperature to maintain the charge and the sludge in the liquid state. The column temperature can not be higher than the critical temperature of the solvent.

 Minimal pressure should be used to avoid solvent vaporization and sludge loading. Practical considerations, such as equipment, economy and other similar factors, are the only limitations imposed on the maximum pressure, which can be used.

 The terms "column temperature", "zone temperature", and similar expressions used in the context of the invention refer to the temperature of the column wall or the portion of the column wall defining an area. sludge, solvent and sludge separation products may or may not reach the same temperature as the wall of the column, depending on the flow rate of these materials. large, so that these materials reach the temperature of the wall of the column.Of course, the materials receive heat from the wall of the column by combustion.

 Although the column pressure is generally uniform over the entire column, the column temperature generally varies from one region or zone of the column to another.

Since the sludge has a relatively high content of solids and high molecular weight polar substances, it is the most viscous and requires the highest temperature. Thus, the zone in which this sludge is collected is typically operated at a temperature at least about 200 ° above that of the remainder of the column.

 Although the quantitative temperature and pressure ranges can not be set globally, by way of illustration and using hexane as a solvent, a typical minimum column temperature (the sludge collecting zone) can be cited. set apart) of at least about 100C and preferably about 1400C. The corresponding pressures are typically about 12.7 and 14.1 kg / cm 2. A typical maximum temperature is about 2250C and preferably about 2000C with corresponding pressures of about 31.7 and 23.0 bar. Although the temperatures of the sludge collection zone are respectively generally higher than at approximately 200 ° C., with comparable pressures, the collecting zone of the waste sludge preferably has a temperature of at least about 1500 ° C. and very particularly preferably about 1800 ° C.

 Extraction of the upper oil from the slurry is at least partially dependent on the weight ratio of solvent to slurry charged to the vertical column. Generally, the solvent / oil ratio used in the implementation of the invention is even greater than the solids content of the sludge is important. The use of a larger solvent / oil ratio leaves, under these circumstances, a greater quantity of polar liquids remaining in the sludge, these polar liquids favoring the coalescence of the solids and, consequently, improving the fluidity of the flow. A minimum weight ratio of about 0.5: 1 may be used although a ratio of about 0: 6: 1 is preferred. Practical considerations, such as energy efficiency, are the only limitations imposed on the maximum weight ratio, although a maximum weight ratio of about 5: 1, and preferably about 1: 1, be typical. A weight ratio of about 0.8 / 1 is particularly preferred. Generally, if the weight ratio is less than 0.5, i.e., less than 0.5 / 1, the recovered asphaltene has a lowered viscosity, which indicates poor separation from the production liquid. In addition, the detection of an interface between the residual sludge and the solvent-sludge phases becomes difficult, the selective removal of the residual sludge from the vertical column itself becoming all the more difficult as this difficulty of detection. staccroSt. If the weight ratio is greater than about 1, the sludge loading capacity (volume per unit time) is sacrificed and additional costs and services are introduced.

 Although it is possible to vary at will the physical characteristics (cut and shape of the envelope and the channel) of the vertical column used according to the invention, said column is typically a hollow cylinder of elongated shape or a structure of pipe form having a length / diameter ratio (LOD) of between about 40 and 2 and preferably between about 20 and 5. the column can be made of any suitable material, but materials such as steel, known for their good use characteristics at high temperatures and pressures are preferred. The column generally comprises three zones: a first zone or clarification zone, a second zone or zone of contact and a third zone or collector zone.

 The first zone or clarification zone is gen- erally the upper part of the column, equipped with an extraction outlet for the upper oil-solvent fraction and starts above an inlet port equipped to introduce the sludge. in the second zone or contact zone. This first zone or clarification zone collects the solvent and the upper oil flowing upwardly from the second zone or contact zone for final disposal from the column. The function of this clarification zone is to provide a region for the gravity separation of any finely divided solids that may have been entrained from the contact zone by the solvent and the higher oil. Accordingly, it is desirable that the solvent and the upper oil are at rest, that is to say that they have little or no convection currents, to promote the re-epalate of any finely divided solids in the contact zone. In large-scale treatments, vertical baffles or other construction features may be useful in pocketing these convection currents and the resulting presence of finely divided solids in the column's taste flow.

 The second zone to the contact zone is generally the middle part, that is to say the part between the first and third zones of the column, and it is generally the greater part of the column (relative to the overall length). In this zone, the sludge descends along the column, partially forming a mixture that rises the stream, partially in a counter-current mode. Although the upper oil / solvent phase which rises the stream is substantially completely mixed in. this second zone (due to the difference in density between the upper oil and the solvent and because of the convection currents), there is a clear circulatior z against the flow of the residual sludge downward opposing the updraft the upper oil / solvent phase. This second zone is equipped with an inlet or inlet of the mud, at its top or in the vicinity thereof, and an inlet or solvent inlet, in the bottom or in the vicinity of it. The use of interior arrangements in this area may be useful, particularly in large-scale operations, for interrupting convection currents. All these interior arrangements must be other designed to avoid the accumulation of an asphaltenic residue, such so that their exposed surfaces are generally not inclined more than 30 degrees from the vertical axis of the column.

 The third zone or collector zone is generally the lower portion of the column and typically has an enlarged diameter relative to that of the first and second zones. This area collects the sludge, i.e. the slurry comprising finely divided solids and other materials, which is not soluble in the polar solvent, for ultimate disposal from the column. The wall of the column defining this zone is generally maintained at a higher temperature than the wall defining the zone dry zone, since the residual sludge, which is collected in the third zone, has a viscosity greater than that of the feed, of the higher oil or solvent and thus requires a higher temperature to maintain its liquid state. As the third zone is generally operated, even as the first and second zones, continuously, it is believed that the temperature difference presented between the wall defining the third zone and the wall defining the second zone is not comparable to the temperature difference between the content of the second zone and the content of the third zone.

However, it is believed that the higher temperature of the wall defining the third zone has the effect of hindering the accumulation of the solids-containing waste phase along the interior of the wall, which promotes permanent unloading and uninterrupted residual sludge.

 The third zone is also equipped with an outlet for the waste sludge, which outlet can be located at any suitable point in said zone, but which is preferably situated in the center of the bottom of this zone. This has the effect of preventing the solvent and the upper oil from escaping by bypassing the waste sludge. The outlet for the sludge may be equipped with any conventional means for facilitating the removal of sludge from said zone, such as a valve, a worm, or a reprocessing machine.

 Other characteristics and advantages of the invention will become apparent in the following detailed descriptions of several embodiments of the invention, given by way of indicative but nonlimiting examples, and with reference to the attached drawing on which it has been used. the same numerical references to designate identical parts.

On this drawing
FIG. 1 represents a specific preferred embodiment of a vertical column
FIG. 2 is a schematic flow diagram illustrating the vertical column of FIG. 1 in specific combination with a conventional separation apparatus, upstream
FIG. 3 represents a schematic functional diagram illustrating a variant of the combination represented in FIG. 2.

 To simplify the description, various components of the equipment, such as valves, fittings, condensers, pumps and others, have been omitted. However, it is understood that specialists in the technical sector considered can use, as they wish, these conventional accessories.

 Referring first to FIG. 1, there can be seen a vertical column 10 which includes a first zone or zone of clarification 11, a second zone or zone of contact 12 and a third zone or zone of collector 13. The zone 11 is equipped with an outlet 14 for the upper oil / solvent phase and a heating jacket it has. Zone 12 is equipped with an inlet 16 for the sludge, an inlet 17 for the solvent and a heating jacket 12a. Zone 13 is equipped with an outlet 19 for the waste sludge and a heating envelope 13a.

 In FIG. 2, the column 10 is connected to an adiabatic expansion tank 22 via lines 21 and 23. A distillation unit 26 equipped with an extraction line 28 is connected respectively to the expansion tank 22 via line 24. and at the column 10 by lines 27 and 23. The lines 27 and 23 are coupled to each other. A separator 31 is connected to the column 10 by the pipe 29. A pipe 33 emanates from the separator 31, while a pipe 32 joins the separator 31 to the condenser 38 which is, in turn, joined to the column 10 by the pipes coupled 39 and 23.

 In FIG. 3, a separation unit 34 replaces the adiabatic expansion flask 22 and the distillation unit 26 of FIG.

The unit 34 is connected to the column 10 by lines 21 and 23 and is equipped with an extraction line 37. The column 10 is equipped with an extraction line 29.

 Having thus described the apparatus and with reference now to FIG. 1, it can be seen that in column 10, a sludge is continuously fed through the inlet 16, while a non-polar solvent is simultaneously and continuously charged. by the inlet 17. Said solvent passes through the zone 12, while the sludge simultaneously passes through said zone by descent. During this continuous simultaneous crossing, the solvent and the sludge are in intimate contact and said solvent extracts from said slurry the upper oil, which is soluble in the solvent under the conditions prevailing in zone 12, thus producing a first fraction comprising the solvent and the upper oil and a second fraction (waste sludge) comprising finely divided solids and polar liquids.The solvent and the higher oil are continuously transported in zone II from which they are removed by the outlet 14. The waste sludge is collected continuously in the zone 13 and removed from it by the outlet 19.

 Referring now to FIG. 2, it can be seen that the solvent / higher oil mixture present in zone II of column 10, in the form of a substantially resting bath, is eliminated as head flow. the line 21 is sent to the expansion tank 22, where a quantity of solvent is separated from the upper oil to be recycled to the column 10 via line 23.

The remainder is transferred. of the solvent / higher mixture in distillation unit 26, where the remaining solvent is distilled off as the overhead product which is recycled to column 10 via lines 27 and 23, while the upper oil is withdrawn. as a basic flow through the extraction outlet 28.

 The waste sludge collected in zone 13 of column 10 is extracted in the form of a flow which is passed through separator 31 via line 29. Separator 31 collects any quantity of solvent present in the residue for recycling. in column 10 through line 32, condenser 38 and lines 39 and 23. Remaining residual sludge is withdrawn as base flow through line 33.

 Referring now to FIG. 3, it can be seen that the overflow from column 10 can be transferred (via line 21) to a single stage solvent extraction (recovery) unit, such as In the latter, the solvent is separated from the upper oil to be recycled to the column 10 through the pipe 23, while the extract is withdrawn through the pipe 37. The choice between the unit 34 and the combination of units 22 and 26 is governed by the needs of the practitioner.

 The high solids sludge thus recovered is suitable as feed raw material for gasification. The hydrogen / carbon ratio in this material is generally equal to or less than that of the coal used as the feedstock for liquefaction. Thus, if this material is used as a fuel, the hydrogen expenditure is rendered minimal.

The higher oil produced according to the invention is desirable as a recycle oil, as a low sulfur fuel or as a raw material for petrochemicals. This material is generally recovered as a bottom stream from a solvent distillation unit.

 The process of the invention is particularly well suited for the separation of sludge produced by hydrogenation of coal at elevated temperature into a first and a second fraction of divided solids and polar liquids. Said mud differs in several important ways from petroleum type materials.

 In the first place, sludges of the invention typically contain about 2 to 15% by weight of ash and about 8% by weight of unconverted organic solids.

 Second, the softening temperature of the waste sludge tends to be considerably higher than that of petroleum asphaltenes. In step, while the propane slurry separators (deasphalter) can operate at temperatures below 1000 C with a fluid waste product, the viscosity of the asphaltenic residue produced in accordance with the invention is typically between 100,000 and 200,000 cps. at 2000 C.

 Thirdly, the coal liquids according to the invention tend to contain a larger fraction of solvent insoluble oil, i.e., polar liquids.

 Fourthly, because of the strongly aromatic nature of the coal-derived oil and the large amounts of hetero-atom-containing compounds, particularly phenolic organic compounds, the difference in interfacial tension between the higher oil and the solvent tends to be higher. to be larger for coal-based oil than for oil-based oils. It is believed that the latter difference is clearly at the origin of the reaction carried out in the process of the invention. The "Marangoni" effect is directly related to this difference in interfacial tension.

 It is admitted that the extraction mechanism occurring in the implementation of the process of the invention is a manifestation of the "Marangoni" effect, the description of which follows. When an oil containing a mixture of polar and non-polar species is contacted with a nonpolar solvent, interfacial tension forces tend to cause the concentration of nonpolar species on the surface of the oil. These non-polar species are rapidly extracted by the non-polar solvent, leaving a high concentration of polar species in the vicinity of the oil surface with a relatively high inter-facial tension, which represents a thermodynamically unstable situation.

 This thermodynamic driving force creates circulation patterns in the oil phase that transfer nonpolar species from within the oil phase to the interface where they are extracted. These flow patterns result in rapid interface movement and extremely high mass transfer rates.

 The inter-facial tension forces, which control these flow patterns, are counteracted by the viscosity effects in the oily phase. As a result, a high viscosity in the vicinity of the oil surface has the effect of damping the flow patterns.

 When the solvent-oil interface is generated by introducing oil into the solvent in the form of drops, for example from a small tube, the Marangoni instability leads to a pronounced increase in the concomitant processes of dispersion. and dissolution, i.e. rapid destruction of the drop into many smaller droplets, which is accompanied by an extraction of the upper oil in the solvent. Other studies have shown that when using a viscous oil or polar solvents such as benzene or toluene, the rate of rapid destruction does not occur. This "Marangoni" instability is believed to occur under the operating conditions of the present invention. Accordingly, the choice of the solvent used according to the invention is preferably such that the "Marangoni" effect is favored. Solvents which do not favor this effect, such as benzene or toluene, have the effect of literally extracting all the liquid from the suspension, thus producing a powder as the final discharge product constituting the withdrawal flow.

In this form, the polar liquids are not separated from the upper oil but are entrained in the clarification zone from which they are removed forming a part of the overhead flow.

 The instability "Marangoni" strongly increases the liquid-liquid extraction by ensuring large inter-facial expanses, which thus reduces the required residence times in the extraction zone.

this in turn allows the use of equipment with smaller volume dimereions for a given volume of sludge and solvent and simplifies the construction of the sludge inlet system, ie eliminates the need to tightly adjust the size of the initial mud droplet previously required to obtain an extremely fine dispersion of the sludge in the solvent. Thus, the essence of the invention is the use of one of the solvents of a specific group of solvents in combination with a temperature difference between different parts of the column wall to facilitate the handling of the residues as This combination not only has the effect of making the implementation of the invention easy, but it also promotes a desirable separation of the upper oil from polar liquids and finely divided solids.

 The following examples illustrate the invention without being in any way limiting. Unless otherwise stated, all parts and percentages are by weight.

Apparatus and technique
A jacketed vertical column having an internal diameter of 7.62 cm and a length of 1.37 m is used, having a similar arrangement to that shown in FIG. 1. The first and second zones are at a temperature of about 1600 ° C. and a pressure of about 14.1 bar, while the third zone is operated at a temperature of about 200 ° C. under a pressure of about 14.1 bar. The column pressure is adjusted by a back pressure regulator and a valve provided at the outlet of the heated upper solvent-oil phase (1500 C).

This output feeds the adiabatic expansion balloon. In the latter, the solvent is distilled off, removed and consecutively condensed and recycled to a solvent feed tank. The upper oil from the flash drum is removed from any residual solvent by a continuously fed distillation unit.

 The sludge is removed from the column via a control valve. A level controller is used to detect the interface between the phases of the waste sludge and the upper solvent-oil mixture to adjust the asphaltene outlet valve.

 Hexane is used as a solvent by feeding the column with different slurries at the rate of about 20.4 kglh. A hexane / sludge weight ratio of about 0.8 l is used.

Analytical protocols
In the following examples, the analytical protocols described below are used:
Viscosity:
The viscosities of liquids produced at 250 ° C. are measured using a "Brookfield" viscometer. The ashes of these liquids are not removed prior to measurement.

insoluble in toluene
The liquid product (40 g) is shaken with toluene (160 g) and centrifuged consecutively. The supernatant liquid is decanted, the remaining residue, the toluene insoluble hydrocarbons and the ash are dried under vacuum at 100 ° C. The ash content of the residue is determined by the ANSI / ASTM method.
D482-74.

Asphaltenes:
The liquid product (25 g) was shaken with n-hexane (100 g) and centrifuged consecutively. The supernatant liquid is decanted, the residue is dried under vacuum at 1000 ° C. (a mixture of ash, of insoluble in toluene and of hydrocarbons soluble in toluene which are insoluble in n-hexane, that is, say the asphaltenes), then we weigh it. The asphaltene content is determined by subtracting the insoluble matter in the toluene and the ash previously determined, in total of the insoluble in hexane.

Coal analysis
The coal used to generate the various liquefied liquids purified as described below, are bituminous coal from Pittsburg's Allison No. 8 mine, milled, dried, pulverized and sorted such that 99.9% pass through a sieve. having a mesh aperture of 0.124 mm. The sulfur content is about 3.9%.

Examples 1-3
In Tables I-III, data from three operations using different sludge, ie in Table I: a flow from a hydrocyclone (at 12.6% ashes), Table II: a liquefaction product (at 5.2% ash) and in Table III: centrifuge head product <at 2.1% ash). The 6SHC heat of combustion is determined according to ANSI / ASTM D2015-66 and the Ramsbottom carbon is determined according to ANSI / ASTM D524-76.

TABLE I
REMOVAL OF IMPURITIES FROM A MUD
HAVING A HYDROCYCLONE

<tb><SEP> Liquid
<tb><SEP> Load <SEP> Product <SEP> Asphaltenes
<tb><SEP> purified
<tb> Quantity, <SEP> kg <SEP> 234 <SEP> 167 <SEP> 60.8
<tb> Quantity <SEP> (Z <SEP> in <SEP> weight) <SEP> 100.0 <SEP> 73.3 <SEP> 26.7
<tb> Analyzes <SEP> ::
<tb> Viscosity, <SEP> cps, <SEP> 250C <SEP> 320 <SEP> 60 <SEP> - <SEP>
<tb> Insoluble <SEP> in <SEP><SEP> toluene, <SEP> Z <SEP> 9.8 <SEP> 0.84- <SEP>
<tb> Asphaltenes, <SEP> Z <SEP> 21.2 <SEP> 1 <SEP> 18.6- <SEP>
<tb> Ash, <SEP> Z <SEP> 12.4 <SEP> 1 <SEP><SEP> 0.33 <SEP> 41.2
<tb> Carbon, <SEP>% <SEP> in <SEP> Weight <SEP> - <SEP> - <SEP> 48,9
<tb> Hydrogen, <SEP>% <SEP> in <SEP> weight- <SEP> - <SEP> 3,19
<tb> Sulfur, <SEP>% <SEP> in <SEP> Weight <SEP> - <SEP> - <SEP> 4.1
<tb> Analysis <SEP> of <SEP> nitrogen, <SEP> Z <SEP> in <SEP> weight <SEP> - <SEP> - <SEP> 0.72 <SEP>
<tb><SEP> Carbon <SEP> Ramsbottom, <SEP>% <SEP> in <SEP> Weight <SEP> - <SEP> 11.1 <SEP> 72.7
<Tb>
TABLE II
REMOVAL OF IMPURITIES FROM A SLUDGE
LIQUEFACTION

<tb><SEP> Liquid
<tb><SEP> harge <SEP> product <SEP> Asphaltenes
<tb><SEP> purified
<tb> Quantity, <SEP> kg <SEP> 1840 <SEQ> 1450 <SEP> 326
<tb> Quantity, <SEP> (% <SEP> in <SEP> weight <SEP> of <SEP> load) <SEP> 100.0 <SEP> 79.17 <SEP> 17.67
<tb> Quantity, <SEP> (Z <SEP> in <SEP> weight <SEP> of <SEP> products) <SEP> - <SEP> 81,76 <SEP> 18,24
<tb> Summary <SEP> = <SEP> 96.8 <SEP>%
<tb> Analyzes <SEP> ::
<tb> Viscosities, <SEP> cps, <SEP> 25 <SEP> C <SEP> 632 <SEP> 152
<tb> Insoluble <SEP> in <SEP><SEP> toluene, <SEP> Z <SEP> 11.81 <SEP> 3.12 <SEP>
<tb> Asphaltenes, <SEP> Z <SEP> 33.47 <SEP> 29.93 <SEP> - <SEP>
<tb> Ashes, <SEP> Z <SEP> I <SEP> 5.02 <SEP> 0.12 <SEP> 28.14
<tb> Carbon, <SEP>% <SEP> in <SEP> weight <SEP> - <SEP> 61.63
<tb> Hydrogen, <SEP> Z <SEP> in <SEP> Weight <SEP> i <SEP> - <SEP> 3.99
<tb> Sulfur, <SEP>% <SEP> in <SEP> weight <SEP> - <SEP> - <SEP> 2.94
<tb><SEP> Hc <SEP> Kcal / g <SEP> - <SEP> - <SEP> 2740
<Tb>
TABLE III
ELIMINATION OF IMPURITIES FROM A MUD (1) COLLECTED
AT THE HEAD OF A CENTRIFUGE

<tb><SEP> Liquid
<tb><SEP> Load <SEP> Product <SEP> Asphaltenes
<tb><SEP> purified
<tb> Quantity, <SEP> Z <SEP> in <SEP> weight <SEP> 100.00 <SEP> 88.2 <SEP> 11.7
<tb> Analysis
<tb> Viscosity, <SEP> cps, <SEP> 25 C <SEP> 670 <SEP> 83
<tb> Insoluble <SEP> in <SEP><SEP> toluene, <SEP> Z <SEP> 9.1 <SEP> 2,4
<tb> Asphaltenes, <SEP> Z <SEP> 36 <SEP> 29
<tb> Ash, <SEP> Z <SEP> 1.9 <SEP> 0.09 <SEP> 17.7
<tb> Carbon, <SEP> Z <SEP> in <SEP> weight <SEP> - <SEP> - <SEP><SEP> 72.0
<tb> Hydrogen <SEP> Z <SEP> in <SEP> Weight <SEP> - <SEP> - <SEP><SEP> 4,2
<tb> Sulfur, <SEP> Z <SEP> in <SEP> Weight <SEP> - <SEP><SEP> - <SEP> 1,7
<tb>#Hc,<SEP><SEP> Kcal / g <SEP> - <SEP> - <SEP> 3330
<tb> Carbon <SEP> Ramsbottom, <SEP> Z <SEP> in <SEP> weight <SEP> - <SEP> - <SEP> 74 <SEP>
<tb> (1) represents average data based on several tests
made with this type of load. As a result, we do not have
information on total feed and feed material
recovery and on the balance sheet of the materials.

 These data demonstrate, on a wide range of sludges containing solids, the low ash content of the purified liquid produced (head flow) and the low residual content of hexane-soluble hydrocarbons from the waste sludge.

Example 4
A series of experiments were conducted to determine the degree of solubility of an oil derived from coal, respectively in pentane, hexane (a mixture of C 6 paraffinic products as contained in Hexane-based solvents). commercial grade), cyclohexane, n-decane and toluene. For each solvent, the solubility of the oil is measured for a series of solvent / oil ratios. The solubility of the oil is determined by weighing the appropriate amount of solvent and oil in a 224 g flask, shaking mechanically the vial for at least 20 minutes to intimately mix the two substances, centrifuging the vials containing the mixture for at least 20 minutes to entrain the collection of the insoluble phase in the bottom of the vial, decanting the liquids from the insoluble residue, by vacuum drying the residue at about 80 ° C, determining the weight of the residue and finally calculating the percentage of the sample that is insoluble (soluble oil = 100% - insoluble 2) The results are listed in Table IV .
TABLE IV
PERCENTAGE OF TECHNICALLY YES IS INSOLUBLE

<tb> Report
<tb> Weight <SEP> of <SEP> solvent <SEP> S <SEP> o <SEP> 1 <SEP> v <SEP> a <SEP> n <SEP> t
<tb> Weight <SEP> of oil <SEP> entane <SEP> Hexane <SEP> Cyclohexane <SEP> n-decane <SEP> toluene
<tb> 0.1 <SEP> 36.08 <SEP> 34.76 <SEP> - <SEP> - <SEP> - <SEP>
<tb> 0.2 <SEP> 28.03 <SEP> 26.37 <SEP> - <SEP> - <SEP> - <SEP>
<tb> 0.4 <SEP> 41.08 <SEP> 36.54 <SE> 19.8 <SE> 25.8 <SE> 9.8
<tb> 0.8 <SEP> 44.44 <SEP> 39.99 <SEP> 18.1 <SEP> 27.5 <SEP> 9.8
<tb> 1.0 <SEP> - <SEP><SEP> - <SEP><SEP> 18.9 <SEP> 27.6 <SEP> 9.4
<tb> 1.6 <SEP> 46.26 <SEP> 39.26 <SEP> - <SEP> - <SEP>
<tb> 3.2 <SEP> 43.21 <SEP> 36.71 <SEP> - <SEP> - <SEP> - <SEP>
<tb> 6.4 <SEP> 43.36 <SEP> 30.20 <SEP> - <SEP> - <SEP> - <SEP>
<tb> Sample
<tb> oil <SEP> A <SEP> A <SEP> B <SEP> B <SEP> B
<Tb>
Oil samples A and B are both samples of coal liquefaction products having initial boiling points of about 1500C, which were centrifuged prior to said experiment to remove substantially all of the solids present therefrom. exception of a small fraction of these (less than about 2-3% of the sample are filterable solids).

Example 5
A series of experiments is carried out as in Example 4 using hexane and decane as solvents. The oil used is the ash-rich fraction obtained by treating the suspension produced above 1500C obtained by the liquefaction with the hydrocyclone.
TABLE V
PERCENTAGE OF SAMPLE WHICH IS INSOLUBLE (*)

<tb><SEP> Report <SEP> S <SEP> o <SEP> 1 <SEP> v <SEP> a <SEP> n <SEP> t <SEP>
<tb><SEP> weight <SEP> of <SEP> solvent
<tb><SEP> weight <SEP> d <SEP> oil <SEP> Hexane <SEP> Decane <SEP>
<tb><SEP> 0.1 <SEP> 19.79 <SEP> 21.14
<tb><SEP> 0.3 <SEP> 13.17 <SEP> 16.86
<tb><SEP> 0.7 <SEP> 24.87 <SEP> 24.75
<tb><SEP> 1.0 <SEP> 28.71 <SEP> 26.91
<tb><SEP> 2.0 <SEP> 28.96 <SEP> 30.94
<tb><SEP> 4.0 <SEP> 29.63 <SEP> 26.23
<tb> (*) <SEP> Insoluble <SEP> in <SEP> the sample <SEP> initial <SEP> counted <SEP> free <SEP> of
<tb><SEP> ashes.
<Tb>

In order to assess the effectiveness of the precipitation by the solvent, the ash contents in the decanted liquids are determined for samples chosen as shown below.
TABLE VI
PERCENTAGE OF ASHES IN THE SOLVENT
AND DECANT OIL

<tb> Report <SEP> Solvent
<tb> Weight <SEP> of <SEP> solvent <SEP>
<tb> Weight <SEP> of oil <SEP> Hexane <SEP> Decane
<tb><SEP> 0.1 <SEP> 0.02 <SEP> 0.01
<tb><SEP> 0.3 <SEP> 0.0 <SEP> 0.0
<Tb>
Several conclusions appear by studying the values presented in Tables IV-VI. First, while the quantity of insoluble matter shows variations according to the oil used and the solvent / oil ratio, and to a lesser degree, of the experimental uncertainty, there is a greater amount of insoluble material recovered for a given solvent / oil ratio and a given oil sample when using pentane, hexane, cyclohexane or decane (all solvents non-polar) only when the solvent is toluene (polar solvent).

 In the second place, when the solvent is toluene, much less insoluble material is obtained because of the higher solubility of the oil drawn from the coal in toluene than in paraffinic hydrocarbons.

 Third, for very low solvent / oil ratios, the ash is very efficiently removed from the soluble oil by practicing the invention. Centrifugation of all the oil samples results in ash contents of 1-2% in the decanted oil.

 Fourthly, because of the increased solubility of the oil in hydrocarbon solvents at elevated temperatures, it can be expected that the operation of the deasphalter with an aromatic solvent, such as toluene, will result in a small amount of oil. non-solid residue separated as insoluble materials. The residue obtained under these circumstances is not a viscous mud but a powder moistened with solvent. Problems with the removal of this residue prevented further operation with toluene as a solvent. Xylenes, ethylbenzene and other monoaromatic compounds can be expected to behave similarly to toluene.

Example 6
A study at room temperature is carried out to observe the effect of the solvent on the production of the "Marangoni" instability.

Hexane is placed in a filled glass container to a height of about 15.2 cm. As the test sample, a coal-derived oil containing about 0.1% ash, 1% toluene-insoluble material and 22% asphaltenes was used. When this oil is added dropwise to hexane from about 2.54 cm above the surface of the liquid hexane, a rapid dispersion in drops is observed. A photographic study of the phenomenon indicates that the droplet dispersion begins before the oil has penetrated hexane for more than 2.54 cm. Secondary droplets are formed with diameters less than 1 / 20th of that of the initial oil droplet in one second and before the oil has penetrated hexane for more than 5.1 cm At the same time, a disturbance of the solvent in the vicinity of this formation indicates that the extraction of a portion of the oil has occurred.

 When performing the identical experiment using toluene instead of hexane as a solvent, no dispersion in drops is produced. The drop of oil is deposited through the solvent and remains on the bottom of the container, minimal extraction having occurred in this case. The toluene solvent changes only slightly in color as the drop of oil passes through it.

 This is in favor of the importance of the "Marangoni" effect in the quick and efficient extraction of deasphalter charge suspension. The choice of solvents, which are less polar than monoaromatic compounds, for example, C 5 -C 6 paraffinic products, is thus essential to obtain a proper operation of the process.

Example 7
Using the apparatus and technique of Examples 1-3, an extraction experiment is performed in which an oil drawn from coal, having the composition described below, is treated.

The oil feed rate is about 2.20 kg / h and the hexane feed rate is about 2.20 kg / h and the hexane feed rate is about 16.6. kg / h. For this experiment, the temperature of the extraction zone of the column is about 1900C. The residue collection zone is warmer, i.e., the wall temperatures are 2040C and 2070C, respectively, in the middle and bottom of the collector zone.

The temperature in the center of the third zone is 1950C. Operation under these conditions resulted in derivation of significant amounts of hexane and hexane soluble oil through the residue outlet line. About 15% by weight of the material in the residue collection vessel is a mixture of hexane and low viscosity oil instead of the desired viscous slurry. A sample of the oil after settling is analyzed as indicated below. A balance of hexane material indicates that much more than the usual amount of hexane has escaped through the exit of the third zone.
TABLE VII
ANALYZES

<tb><SEP> Oil <SEP> Oil <SEP> Oil <SEP> (t) <SEP> Residue
<tb><SEP> load <SEP> produced <SEP> decanted <SEP> total
<tb> Viscosity <SEP> to <SEP> approx. <SEP> 25 C <SEP> 375 <SEP> 9i <SEP> 3000
<tb> Ash <SEP> Z <SEP> 8.14 <SEP> 0.002 <SEP> 14.22 <SEP> 30b54
<tb> Insoluble <SEP> in <SEP> the
<tb> toluene <SEP> Z <SEP> 9.78 <SEP> 0.83 <SEP> 17.26 <SEP> - <SEP>
<tb> Asphaltenes <SEP>% <SEP> 21,12 <SEP> 17,17 <SEP> 25,80 <SEP> (decanted from the material present in the container
residue collector.

Example 8
Continuing the operation described in Example 7, the extraction process is continued while the temperature of the wall of the third zone is increased. After reaching the steady state, the following temperature profile is recorded: Zone 2, 190 C; wall temperature in the middle and bottom of zone 3, 2250C and 255 C; temperature in the center of zone 3, 212 C. Under these operating conditions, no decantable oil in the residue collection zone. The quality of the product is as follows
TABLE VIII
ANALYZES

<tb><SEP> Oil <SEP> Oil
<tb><SEP> loaded <SEP> produced
<tb> Viscosity <SEP> to <SEP> approximately <SEP> 25 C <SEP> 375 <SEP> 62
<tb> Ash <SEP> Z <SEP> 8.14 <SEP> 0.004 <SEP> 35.15
<tb> Insoluble <SEP> in <SEP><SEP> toluene <SEP> 9.78 <SEP> 0.88 <SEP>
<tb> Asphaltenes, <SEP> Z <SEP> 21.12 <SEP> 17.08 <SEP>
A comparison of the values presented in the Tables
VII and VIII is in favor of the need to maintain the wall temperature of the third zone at a value of about 20 ° C higher than that of the wall temperature of the remainder of the column, if a viscous sludge is intended to be recovered from the third zone.

Claims (7)

R1VENDICATIONS  An improved process for separating a sludge feed produced by high temperature hydrogenation of a solid hydrocarbon fuel and comprising finely divided solids, polar liquids and a high quality liquid oil, into a first fraction comprising said top liquid oil. and a second fraction comprising said finely divided solids and said polar liquids, characterized in that  (a) the sludge feed is mixed with a nonpolar liquid solvent which consists of a C 5 -C 6 aliphatic or alicyclic hydrocarbon or a naphthenic or paraffinic fraction of a coal liquefaction product containing less than 10% by weight of aromatic compounds, the mixture being formed in a vertical column comprising a clarification zone, a contact zone and a collecting zone, the clarification and contact zones operating at a temperature of between 100C and 2500C and under a sufficient pressure, for maintaining the sludge and the solvent in the liquid state, but below 31.7 bar, the sludge being introduced into the column at the top of the contact zone or in its vicinity, the solvent and the sludge being mixed in a ratio of weight of at least 0.5 1 and brought into contact so that the solvent  (1) crosses the column by ascent while the mud  crosses the column by descent  (2) is in intimate contact with the mud as  the solvent and the mud pass through the  column ; and  (3) extracts the upper liquid oil  from the mud, as the solvent and mud  cross the column simultaneously;  (b) recovering the first fraction from the clarification zone of the column as an overflow (or overflow); and  (c) recovering the second fraction from the collector zone of the column in the form of a base flow consisting of a viscous sludge.  2. Method according to claim 1, characterized in that the sludge is produced from the liquefaction of coal.  3. Method according to claim 2, characterized in that the solvent / sludge weight ratio is between about 0.6 l and about 5 1.  4. Process according to claim 3, characterized in that the sludge solids content is less than 25% by weight of the sludge.  5. Process according to claim 4, characterized in that the base flow comprises less than 65% by weight of solids.  6. Method according to claim 5, characterized in that the liquid solvent is at least one aliphatic or alicyclic hydrocarbon C5 Cg.  7. Method according to claim 6, characterized in that the temperature of the portion of the wall of the column, which defines the collecting zone, is at least 1500C.