US3162594A - Process for producing liquid fuels from coal - Google Patents

Description

E; GoRlN 3,162,594

PRocEs For: PRonucING LIQUID FUELS FROM com.

Dec. 22, 1964 Filed April 9, 1962 uw mzON zormdn-mm QZOOm m mw mzoN zoFmm 5m E wbb2-oma mm2-motor.-

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United States Patent itice 3,l02,591l Patented Dec. 22, i964 3,162,594 PRGCESS FOR PRODUCMYG LIQUID FUELS BRGM CAL Everett Gerin, Pittsburgh, Pa., assigner to Consolidation Coal Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Apr. 9, 1%2, Ser. No.. 185,994 9 Claims. (Cl. 20S-57) This invention relates to an improved process for producing liquid fuels such as gasoline from coal. More particularly, this invention relates to an improved process for producing distillable hydrocarbonaceous liquid from ash-containing, non-distillable extract obtained by the solvent extraction f coal.

This application is a eontinnation-in-part of my copending application SerialNo. 81,177, now abandoned, led January 6, 1961, which is assigned to the assignee of this application.

As described in my copending application Serial No. 154,451, filed November 24, 1961, and my US. Patent No. 3,018,242, which are both assigned to the assignee of this application, valuable liquid products such as gasoline may be derived from coal by initially subjecting the coal to solvent extraction, whereby a mixture of coal extract and undissolved coal residue is obtained. After separating the extract from the residue, the extract is catalytically hydrocracked to 'yield an ash-free, distillable hydrocarbonaceous liquid normally boiling below about 500 C. The distillable hydrocarbonaceious liquid, which is sometimes hereinafter referred to as a hydrogen-enriched hydrocarbonaceous liquid, is suitable for refining to gasoline, for example, by a refining scheme such as described in my copending application Serial No. 154,451, supra.

The extract obtained by the solvent extraction of coal, after being separated from the undissolved coal residue, contains a minute, unfilterable amount of metallic contaminants, commonly referred to as ash. If the ash is not removed from the coal extract prior to catalytic hydrocracking thereof, the ash tends to deposit on the `catalyst contained in the hydrocracking zone thereby causing a more rapid decrease in the activity'of the catalyst than otherwise would be experienced; and more importantly, causing a more rapid decrease in the useful life of the catalyst. Such decrease in activity forces resort to more frequent replenishment of the catalyst with either regenerated or fresh catalyst.

innumerable methods have been suggested for removing ash from hydrocarbonaceous liquids or for minimizing the deleterious effect caused by the ash. In most cases, however, these methods have been designed for treating hydrocarbonaceous liquids derived from petroleum. Unfortunately, the methods which remove ash from or overcome the deleterious effect of the ash contained in petroleum-derived liquids normally do not accomplish the same result with ash-containing coal extract, particularly the ash-containing coal extract which is used in the present invention.

Coal extract is not similar nor does it behave similarly to other hydrocarbonaceous materials such as petroleumderived liquids, primarily because coal extract has a completely different chemical structure from that of other hydrocarbonaceous materials. Coal extract, a solid at room temperature, contains very little (in general, less than about weight percent) material boiling below 400 C. The remainder of the extract is essentially non-distilllsoluble. in the petroleum.

able without decomposition. The difference between coal extract and other hydrocarbonaceous materials such as petroleum is best exemplified by the solubility of the respective materials in benzene. Up to weight percent of coal extract is insoluble in benzene, while other hydrocarbonaceous materials, for example, petroleum-derived liquids, are substantially completely soluble in benzene.

It is important to note that the above description of ash-containing coal extract is applicable specifically to the coal extract used in the present invention. Coal extract may be produced which contains no benzene insolubles, for example, if high temperatures (greater than 450r3 C.) and elevated hydrogen pressures are use-d during extraction, coal extract may be obtained which is completely soluble in benzene. This invention, however, is designed to treat coal extract containing benzene insolubles and, in fact, this invention becomes more valuable the higher the amount of benzene insolubles that is contained in the coal extract. Such high. benzene-insoluble containing coal .extracts normally are obtained when it is desired to produce gasoline from coal, for example, as described in my copcndug application, Serial No. 154,451, supra, wherein the result-ing coal extract usually contains greater than 35 weight percent benzene insolubles.

Likewise, coal-extract ash is not similar nor does it behave similarly to ash contained in other hydrocarbonaceous materials such as ash contained in petroleum` derived liquids. The metallic contaminants, i.e., ash, contained in petroleumfderived liquids generally are associated with a porphyrin type of molecule or class of compounds which are to a large extent, if not completely, In contrast, up to 50 weight percent of the metallic contaminants in coal extract, which contaminants have their origin in the coal feedstock, are insoluble, finely divided particles, substantially all of which have particle diameter between 0.01 and 2.0 microns, thereby making it difficult, it not impossible, to remove the particles by commercial mechanical separa, tion methods. The remaining metallic contaminants in the coal extract have a particle diameter below 0.01 micron and frequently a major portion of these remaining contaminants is actually soluble in the coal extract. As hereinafter more fully explained, I have now found that the coal-extract ash which is=below 0.01 micron in diameter, Whether soluble or insoluble in the coal extract, is particularly harmful during catalytic hydrocracking of the coal extract.

The metallic contaminants found in coal extract are metals which usually appear in the form of compounds, for example, silicates, complex aluminum silicates, sulfates, suldes, chlorides, and oxides. The metals include sodium, silicon, iron, calcium, magnesium, aluminum, and titanium.

The following Table I is typical analysis of the metallic contaminants present in a coal extract. The extract was obtained by subjecting Pittsubrgh seam bituminous coal to solvent extraction with tetrahydronaphthalene solvent under the following conditions:

Temperature C 380 Pressure p.s.i.g 600 Solvent/coal (Wt. ratio) 2 Normal residence time minutes 52 The extract was separated (by filtration) from the residue, and the extract was then analyzed for the metallic contaminants. The contaminants are expressed as oxides in the following Table I.

1 The ignition loss is due to subsequent con version of metal compounds tha are stable at the ashing temperature o 1100 I to the corresponding 0x1 es The only previously described method for removing ash from coal extract is to wash ash-containing coal extract with acid. Unfortunately, the cost of the acidic reagents,

particularly concentrated solutions'thereof, and the cost of equipment associated with handling such acidic reagents undesirably increases the total cost of the process. Furthermore, the acidic reagent, even if used in highly yconcentrated form,V generally does not remove all of the ash contained in the extract.

It is preferred to overcome the ash-deposition problem without removing the ash from the extract in a separate treatment step prior to catalytic hydrocracking. Such a scheme is not only desirable from the standpoint of eliminatingla costly ashremoval step prior to hydrocracking, but such a scheme is also desirable from the standpoint of minimizing degradation of the coal extract. For example, it is known that coal extract readily undergoesdegradation when it is subjected to vchemical treatments, particularly at elevated temperatures. Asa result, the extract is more diicult to hydrocrack and gives poorer hydrocracking yields. The degradation fis manifested by the formation of coke and by` the' increase in the high molecular weight, hydrogen decient portion of the ex# tract. The ,benzene-insoluble content of the extract is 'a measure of this undesirable, high molecular weight extract portion.

In my copending application Serial No. 31,445, iled May 24, 1960, now abandoned, which is assigned tothe assignee of this application, I described a process for improving the ash-deposition problem during catalytic hydrocracking of extract without removing the ashV from the coal extract prior to hydrocracking. Specifically, I suggested that a dense bed, liquid phase fluidized catalytic reaction zone be used to produce the distillable hydrocarbonaceous lliquid rfrom the ash-containing coal extract. I found that insoluble ash contained in the coal extract passes through the dense iiuidized bed of catalyst without ydepositing thereon and leaves the fluidized catalytic reaction zone suspended in unconverted coal extract. However, as previously mentioned, extract may contain not only insoluble ash but also soluble ash, i.e., ash particles' that are soluble in the coal extract. I found that when coal extract containing soluble ash is introduced into a dense bed, liquid phase fluidized catalytic hydrocracking zone, the major portion of the soluble ash is converted to insoluble ash. The soluble ash which is not converted to insoluble ash tends to collect on the surfacev and in the pores of the catalyst, thereby deactivating the catalyst.

"Hydrocracking catalyst, as well as other forms of catalyst plurality of sections such that the extract is introduced in countercurrent ow relationship to the hydrocracking catalyst. Thus, the extract initially contacts partiallyV deactivatedrcatalyst thereby minimizing, but not eliminating, catalyst deactivation.

I have now found that inaaddition tothe deactivation caused by the soluble ash, a particular portion of the insoluble ash also causes catalyst deactivation. Specifically, the insoluble ash having a particle diameter below 0.01 micron has the tendency to accumulate in the pores of the catalyst thereby deactivating the catalyst.

vAccordingly, the primary object ofythis invention is toy provide an improved process for minimizing the deleterious effect of coal-extract ash having a'diameter below 0.01 micron (whether the ash is soluble or insoluble in the coal extract) on hydrocracking catalyst during the production of ash-free, distillable hydrocarbonaceous liquid from ash-containing coal extract. 1

In accordance with my invention, ash-containing coal extract, at least a portion of which is insoluble in benzene and which contains at least some ash (either soluble or insoluble in the extract) which is smaller than 0.01 micron in diameter, is subjected to hydrogenation. During hydroe v genation of theV coal extract,'hydrogen is added to the extract under conditions such thatra product comprising a' minor amount of an ash-free, distillable hydrocarbonaceous liquid, which is completely soluble in benzene, and avmajor amount of an ash-containing, non-distillable hydrocarbonaceous liquid is obtained. The non-distillable hydrocarbonaceous liquid comprises at least 50 weight' percent of the coal extract fed to vthe hydrogenation zone.

As a result of the hydrogenation treatment, the non-dis tillable liquid is more soluble in benzene and contains less ash below 0.01 micron in diameter than the original ashcontaining coal extract.. At least a portion of the nondistillable liquid subsequently is catalytically hydro'cracked to produce additional ash-free, benzene-soluble, distillable hydrocarbonaceous liquid. The distillable hydrocarbonaceous liquid (sometimes referred to as hydrogen-en riched hydrocarbonaceous liquid) frornboth hydrogenation yand hydrocracking is suitable for refining to gasoline.

The essence of my invention -is that I have found that about weight percent of the soluble ash and the insolu- Vble ash having a particle diameter below 0.01 micron which is contained in coal extract is associated with the benzene insoluble portion of the coal extract.V In fact, a directrelationship exists between the benzene insolubles and these particular ash components., If the benzene insolublesV are removed from theextract or converted to' benzene solubles, substantially all of the ash having ai diameter below 0.01 micron (whether'soluble or insoluble in the coal extract) is correspondingly removed or agJ glomerated to insoluble ash particles having a particle di# aineter greater than 0.01 micron.

In order to convert benzene insolubles t'o benzene solubles, the extract needs only to be hydrogenated; preferably in the presence of a catalyst so that lower pressures and temperatures may be used. The hydrogen used for hydrogenating the coal extract may be supplied by extraneous hydrogen gas, by hydrogen-transfer from a hydrogentransferring solvent such as tetralin, or by both.

By agglomerating the coal-extract ash prior to catalytically hydrocracking the extract, the ash has a decreased adverse effect on the hydrocracking catalyst. While some agglomerated ash particles will still deposit on the hydrocracking catalyst and thereby cause deactivation, the.

amountof ash entering the interior of the hydrocracking catalyst is substantially reduced. Obviously, maximum-k the uidized catalyst bedV without depositing on1 the' catalyst surface.

' of benzene insolubles.

While it is desirable to suliently hydrogenate the coal extract to convert all of 4the benzene insoluble extract to benzene solubles and thereby agglomerate substantially all of the coal-extract ash to ash particles above 0.01 micron in diameter; it is also desirable to minimize the amount of extract converted to distillable hydrocarbonaceous liquid during hydrogenation. Preferably, the coal-extract is converted during hydrogeuation to a substantially benzene-soluble, non-distillable hydrocarbonaceous liquid with as little distillable hydrocarbonaceous liquid production as possible. The resulting non-distillable hydrocarbonaceous liquid, which diters from the feed coal extract only in terms of the amount of liquid that is soluble in benzene and the amount of ash below 0.01 micron which is contained therein, is catalytically hydrocracked in the presence of an eicient hydrocracking catalyst to produce the distillable hydrocarbonaceous liquid at a lower cost than the distillable liquid produced during hydrogenation. In order to minimize the distillable liquid production in the hydrogenation zone, the amount of hydrogen added is limited to no more than 4.0 weight percent of the extract. As a result, the nondistillable liquid comprises at least 50 weight percent of the extract, and preferably more.

For a better and more complete understanding of my invention, its objects and advantages, reference should be had to the following .description and to the accompanying drawing which is a diagrammatic illustration of the preferred embodiment of lthe present invention.

Preferred Embodiment The following, with reference to the drawing, is a description of the preferred embodiment oi this invention. Extract, obtained by treating bituminous coal such as Pittsburgh seam coal in a solvent extraction zone (not shown) wherein at least 35 weight percent ofthe MAF (moisture-free and ash-free) coal is dissolved, is introduced after separation from the residue into a conventional type mixing zone l0 via a conduit 12. Generally, up to 75 weight percent of the extract is insoluble in benzene and the extract contains approximately 0.10 to 0.30 weight percent ash; up to one-half of which is insoluble ash having a particle diameter greater than 0.01 micron. The remaining coal-extract ash generally consists of soluble ash or insoluble ash having a particle diameter below 0.01 micron; The ,conditions for the preparation of the coal extract do not form a part of this invention, but are further disclosed, for example in my US. Patents 3,018,241 and 3,018,242.

As previously mentioned, this invention Vis particularly suitable for treating coal extracts containing high amounts Such high benzene-insoluble containing coal extracts are obtained when it is desired to produce gasoline from coal by a process such as described in my copending application Serial No. 154,451, supra. In my copending application the coal is treated in a solvent extraction zone until the solvent has extracted, that is, converted or dissolved, between 50 and 80 weight percent of the MAF coal. The resulting extract', after filtration, normally contains more than l35 weight percent benzene insolubles.

Catalyst, introduced via a conduit i4, is mixed with the extract in the zone 1 0 preferably at atmospheric pressure and at a temperature which is suliicient to maintain the extract in the liquid state, generally about 190 C. if lower temperatures are desired, a hydrocarbonaceous solvent may be added to the extract to maintain it in the liquid state. Typical solvents are those which are employed in the solvent extraction zone, for example, tetrahydronaphthalene, Decalin, and various extract hydro grenation and hydrocracking products.

Any conventional type catalyst' commonly used for hydrogenation of coal extract may be introduced into the mixing zone 10. Since ash will cause deactivation of the catalyst used during the hydrogenation treatment', it obviously is desir-able t0 employ inexpensive hydrogenation catalysts which are only suiciently active to accomplish the conversion of the benzene-insoluble extract to benzene solubles. For example, red mud may be used as the hydrogenation catalyst. Preferably, the catalyst is deactivated catalyst which previously has been employed as `the catalyst in a catalytic hydrocracking zone, as hereinafter more fully explained.

A mixture of the extract and the catalyst is continuously withdrawn from the mixing zone 10 via a conduit 16 and introduced into a catalytic hydrogenation zone 18. The hydrogenation lzone 1%8 is preferably a hydrogenation zone which enables Vthe catalyst to be introduced into, maintained therein, and withdrawn therefrom, in the form of a slurry or a suspensoid. if desired, however, the catalyst may be used in the form of fixed, uidized, or gravitating bed within the hydrogenation zone 1S rather than being introduced into the zone 18 in admixture with the extract.

Hydrogen is introduced into the hydrogenation zone 18 via a conduit 2l), wherein it reacts with the extract under the following conditions: 375 to 460 C., 1000 to i000() psig., a hydrogen feed rate in ,the range of 10 to 50 s.c.f./lb. extract feed, and a liquid feed rate in the range of 20 to 150 lbs/ft.3 reaction space. The catalyst concentration in `the hydrogenation zone is maintained within the range of 2.5 to 50.0 weight percent, preferably between about 5 and 25 weight percent. As hydrogen and extract react under the above conditions, benzene-insoluble coal extract is converted to benzene solubles. Correspondingly, soluble ash and insoluble ash having a particle diameter below 0.01 micron contained therein is converted to insoluble ash having a particle diameter greater than 0.01 micron.

As previous.y mentioned, it is desirable to hydrogenate the coal extract such that substantially all of the benzene insolubles are eliminated from the extract; and thus a non-distillable liq? id hydrocarbonaceous hydrogenation product, which is substantially completely soluble in benzene and which contains little or no ash below 0.01 micron in diameter, is obtained. Furthermore, it is also desirable that the coal extract be converted to the nondistillable liquid with as little distillable liquid production as possible. Because of the hydrogenation conditions used, however, some distillable hydrocarbonaceous liquid will be produced. In order to minimize the amount of distillate production during hydrogenation, .the hydrogenation conditions are maintained such that no more than 4.0 weight percent hydrogen is added to the extract whereby the non-distillable hydrocarbonaceous liquid comprises at least 50 weight percent of the coal extract. Thus, the non-distillable liquid may be more efficiently converted to distillable hydrocarbonaceous liquid in a catalytic hydrocraclcing zone, as hereinafter more fully explained.

By non-distillable hydrocarbonaceous liquid, I mean a liquid which is non-distillable without decomposition such as coal extract. In fact, the non-distillable hydrocarbonaceous liquid is the same as coal extract except for the increased amount of hydrocarbonaceous liquid which is soluble in benzene and the lower amount of ash below 0.01 micron that is contained therein.

A product stream is continuously Withdrawn from the catalytic hydrogenation zone 18 via a conduit V22. The product stream comprises catalyst, the distillable hydrocarbonaceous liquid, and the non-distillable hydrocarbonaceous liquid hydrogenation product. These products are introduced into a first separation zone 24 wherein the distillable hydrocarbonaceous liquid, which is ash-free and essentially completely soluble in benzene, is separated from the catalyst and the ash-containing, non-distillable hydrocarbonaceous liquid. The distillable liquid is withdrawn from the zone 24 via a conduit 26. Preferably, substantially all ofthe distillable liquid is subjected to hydroning as hereinafter explained; however, if desired,

Vond separation zone 30.

` at'alyst regeneration zone.

portions of the distillable liquid maybe used for other purposes, forl example, as solventfor the solvent extraction of the coal. l

The catalyst and the non-distillable liquid hydrocarbonaceous product are withdrawn from the first separation zone 24 via a conduit 28 and introduced intoa sec- Y Y The separation zone 30 is preferably a sedimentation zone or one which employs centrifugal force as a means of separating, for example,a hydroclone. This type of separation zone is preferred 1n order to separate the catalyst from the major portion of the.nondistillable hydrocarbonaceous liquid the form of `a concentrated slurry.` It is `desirable to reintroduce at least a portion of the catalyst into thehydrogenation zone; therefore, it is preferred to maintain the catalyst in the form of a concentrated slurryin order to minimize degradation of the individual catalyst particles due to attrition. Catalyst in the form of a concentrated slurry is withdrawn from the separation zone 30 via a conduit 32, While substantially catalyst-free, ash-containing, non- Y distillable hydrocarbonaceous liquid is withdrawn from the zero 30 via a conduit 34. The latter is preferably introduced into a dense bed, liquid phase fluidized catalytic hydrocracking zone 36.

At least a portion of the concentrated catalyst slurry Vis reintroduced into the hydrogenation zoneflS via a conduit 38, while the remaining portionv is introduced-into a Iltration vzone (not shown). At least a portion of the catalyst obtained from :the filtration zone is subsequently treated to remove carbon deposits vin aconvent'ional type The lregenerated Vcatalyst is generally reintroduced into the mixing zone 10. The non- Vdistillable hydrocarbonaceous liquid hydrogenation product separated from the catalyst in the filtration zone is preferably introduced in admixture with the liquid hydrogenation product into the .fluidized catalytic hydrocracking zone 36. If desired, however, a portion of the non-distillable liquid may be subjected to coking, for example, to produceelectrode carbon and a distillate, f

The fluidized catalytic hydrocracking zone 36 kpreferably contains a plurality of sections, as previously mentioned. Hydrocracking catalyst preferably. having a rather narrow size consist within lthe range vof 8 x 100 mesh Tyler Standard screen, eg., 16 x 24 mesh, 24 x 48 mesh,

*of feed, and a liquid feed rate of from l to 150 lbs/ft.3

reaction space. The catalyst employed therein may be .any of the catalysts which are commonly used by those .skilled in the art for hydrocracking extract, such a-s metals of Sub-Groups to 8 of the Periodic Chart, preferably oxides, and combinations thereof. A preferred catalyst is one containing a metal oxide or sulfide of Sub-Group 6 of the Periodic-Chart,i.e., molybdenum, combined with a relatively minor amount of a transition group metal oxide or sulfide such ascobalt` or nickel. The active hydrocracking metals are preferably supported on a hydrous oxide support such as alumina gel.

As hydrogen and the non-distillable liquid. react under the above conditions, a portion of the non-distillable liquid is' converted to an ash-free, benzene-soluble, distillable hydrocarbonaceous liquid product which is continuously withdrawn from the zone 36 via a conduit 40. The remaining non-distillable liquid is withdrawn from the zone 36 Via a conduit 42. The agglomerated ash passes through QI A zone 1S or introduced into a conventional type zone, eg., a delayed coker (not shown). The ash-free, distillable liquid product w1thdrawn via the conduit 40, preferably is admixed with the distillable hydrocarbonaceous liquid hydrogenation product (conduit 26) and the mixture is subjected to hydroiining as hereinafter explained. If desired, however, a portion of the distillate liquids may be used as solvent for the aforementioned solvent extraction of the coal.

Deactivated hydrocracking catalyst-is withdrawn (not shown) from the uidized catalytic hydrocracking zone 36 and preferably at least a portion is introduced into the mixing zone 10 as the hydrogenation catalyst. Normally, catalyst which is tooinactive lfor economic hydrocracking will still be sufficiently active to convert benzene insolubles to benzene solubles. More preferably, however, the deactivated hydrocracking catalyst is crushed prior to use in the hydrogenation zone. Crushing the catalyst restores a substantial amount of activity to the hydrocracliing catalyst. In fact, the crushed hydrocracking catalyst is su'icie'ntly active -to produce, during hydrogenation, a non-distillable hydrocarbonaceous liquid which is substantially completelysoluble in benzene and which contains a substantially reduced amounto'f ash below 0.01 micron in diameter. v

If desired, the above over-all process may be conducted as a continuous, v semi-continuous, or batch'operation. Moreover, in place of the fluidized catalytic hydrocracking zone 36 employed in the preferred embodiment, any conventional type of hydrocracking zone may be employed. Naturally, the use of a hydrocracking zone other than a fluidized catalytic hydrocracking zone will result in increased deposition of ash on the catalyst; however, such deposition will be substantially less than the deposition which occurs when the extract is introduced directly into the treatment. Y i y If desired, :prior to introducing the ash-containing nondistillable liquid hydrogenationy product into the 'hydro- .cracking zone, the liquid product may be treated to remove the portion of the insolubleV ash having a particle diameter greater than 1.2 microns if example,'by filtration.

The ash-free, distillable hydrocarbonaceous liquid product (conduit 26) is introduced into a hydroning zone 46. The distillate feed is Vreacted in the zone 46 with hydrogen in the presence vof a catalyst under the following conditions:

any is present, for

Broad Preferred Temperature 340 to 470 C. 380 to 430 C. Pressure (Total 50D to 4, 500 p.s.l.g. l, 000 to 3, 000 p.s.i.g.

Pressure). Hydrogen Ratio 1,000 to 10, 000 l, 500 to 3, 000 s.c.f./

t s.o.f./bbl. feed. bbl. feed. Llquld Hourly 0. 2 to 2. 0 volume] 0.5 to 1. 5 volume] Space Velocity. volume/hour. volume/hour.

The eiliuent-hydroliner products, recovered from the zone 46 via a conduit 48, are substantially free of nitrogen, oxygen, and sulfur compounds. The effluent products are preferably fractionated to recoVed a gasoline fraction boiling below about 193 C., as further explained in my copending application Serial No. 154,451, supra.

The hydroning catalystmay beV disposed in a fixed stationary bed, or various moving bed or uidized bed y techniques may be used. Generally the fixed bed technique is most satisfactory. Suitable catalystsmay comprise any of the oxides 'or suldes of the transitional metals and especially an oxide or sulfide of aGroup 8 Y metal (preferably iron, cobalt, or nickel) mixed with an oxide or sulfide of a Group 6B metal (preferably molybdenum or tungsten). Such catalysts may be used in undiluted form, but'normally are supported on a absorbent carrier such as alumina,vsilica, zirconia, titania,

coking zone Without the prior hydrogenation 9 and natural occurring porous supports, i.e., activated high alumina ores such as bauxite or clays such as bentonite, etc. Preferably, the carrier should display relatively little cracking activity, and hence highly acidic carriers are generally to be avoided. The preferred carrier is activated alumina.

EXAMPLE Extract, obtained by the solvent extraction of a Pittsburgh seam coal at 380 C. with tetrahydronaphthalene solvent, was introduced into hydrogenation zone in admixture with a catalyst. The extract contained 0.18 weight percent total ash and 38 weight percent benzene insolubles. Approximately half of the ash was insoluble ash having a particle diameter greater than 0.01 micron while the remaining portion of the ash was soluble ash and insoluble ash having a particle diameter below 0.01 micron. The catalyst was crushed, deactivated hydrocracking catalyst that had been previously employed for hydrocracking a similar extract. The catalyst, when originally introduced into the hydrocracking zone, was an alumina base catalyst containing 13 percent by Weight M003 and 3 percent by weight CoO. The catalyst was employed in the hydrocracking zone until no further absorption of ash occurred (the catalyst had absorbed 10.5 weight per cent ash), at which point the catalyst would normally be discarded. The catalyst was withdrawn from the hydrocracking zone and then regenerated with air in order to remove carbon deposits. The regenerated catalyst was crushed such that substantially all the catalyst particles had a particle diameter with the range of about to 200 microns. The actual particle size distribution of the crushed catalyst was as follows:

50 percent by weight of the particles were between 147 and 200 microns 36 percent by weight of the particles were between 74 and 147 microns 14 percent by Weight of the particles were between 0 and 74 microns The conditions of the hydrogenation zone were as follows:

Temperature 440 C.

Partial pressure of hydrogen 3500 psig. Hydrogen feed rate 15 s.c.f./lb. extract Residence time l hour. Catalyst/extract feed ratio 0.046.

The products of prehydrogenation were collected and analyzed.

Yields, percent by weight, of extract feed Substantially all of the non-distillable liquid hydrogenation product was soluble in benzene. Furthermore, approximately 90 weight percent of the soluble ash and insoluble ash having a particle diameter below 0.01 micron contained in the original extract was converted to insoluble ash having a particle diameter above 0.01 micron.

According to the provision of the patent statutes, I have explained the principle, preferred construction, and mode of operation ot my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. An improved process for producing liquid fuels from 10 ash-containing coal extract, said extract being essentially non-distillable Without decomposition, at least a portion of said extract being insoluble in benzene and at least a portion of said ash being below 0.01 micron in diameter, which process comprises (a) subjecting said Sh-containing coal extract to hydrogenation in a hydrogenation zone maintained under conditions such that an ash-containing, nondistillable hydrocarbonaceous liquid comprising at least 50 weight percent of the coal extract is obtained, said non-distillable liquid being more soluble in benzene and containing less ash below 0.01 micron in diameter than said coal extract, and

(b) subjecting at least a portion of said non-distillable hydrocarbonaceous liquid to catalytic hydrocracking in a hydrocracking zone maintained under conditions such that an ash-free, benzene-soluble, distillable hydrocarbonaceous liquid is obtained.

2. An improved process for producing liquid fuels from ash-containing coal extract, said extract being essentially non-distillable without decomposition, at least a portion of said extract being insoluble in benzene and at least a portion of said ash being below 0.01 micron in diameter, which process comprises (a) subjecting said ash-containing coal extract to hydrogenation in a hydrogenation zone maintained under conditions such that an ash-containing, non-distillable hydrocarbonaceous liquid comprising at least 50 weight percent of the coal extract and an ash-free, benzene-soluble, distillable hydrocarbonaceous liquid are obtained, said non-distillable liquid fraction being more soluble in benzene and containing less ash below 0.01 micron in diameter than said coal extract, and

(b) subjecting at least a portion of said non-distillable hydrocarbonaceous liquid to catalytic hydrocraclcing in a hydrocracking zone maintained under conditions such that an ash-free, benzene-soluble, distillable hydrocarbonaccous liquid is obtained.

3. The process of claim 2 wherein the ash-containing coal extract is treated in the presence of a catalyst in said hydrogenation zone, said hydrogenation zone being maintained at a temperature between 375 and 460 C. and at a pressure between 1000 and 10,000 p.s.i.g.

4. The process of claim 2 wherein at least a por-tion of said distillable hydrocarbonaceous liquid from said hydrocracking zone and at least a portion of said distillable hydrocarbonaceous liquid from said hydrogenation zone are subsequently refined to yield gasoline.

5. The process of claim 2 wherein the coal extract is hydrogenated in the hydrogenation zone of step (a) in the presence of a catalytic composite consisting essentially of a crushed, deactivated hydrocracking catalyst.

6. An improved process for producing liquid fuels from ash-containing coal extract, said extract being essentially non-distillable without decomposition, at least a portion of said extract being insoluble in benzene and at least a portion of said ash being below 0.01 micron in diameter, which process comprises (a) adding up to 4.0 weight percent hydrogen to said ash-containing coal extract in the presence of a catalyst in a hydrogenation zone maintained at a temperature between 375 and 460 C. and at a pressure between 1000 and 10,000 p.s.i.g., such that an ashcontaining, non-distillable hydrocarbonaceous liquid comprising at least 50 weight percent of the coal extract and an ash-free, benzene-soluble distillable hydrocarbonaceous liquid are obtained, said nondistillable liquid being more soluble in benzene and containing less ash below 0.01 micron in diameter than said coal extract,

(b) subjecting said non-distillable hydrocarbonaceous liquid fraction to catalytic hydrocracking in a hydrocracking zone maintained under conditions such that 11 an ash-free, benzene-soluble, distillable hydrocarbonaceous liquid is obtained, and (c) therafter introducing at least a portion of said distillable liquid from said hydrocracking zone and at least a portion o-said distillable liquid from said hydrogenation zone into a hydroning zone to yield gasoline. 7. The process of claim 6 wherein said non-distillable liquid fraction from step (a) is substantially completely soluble in benzene and substantially all of said ash contained therein is greater than 0.01 micron in diameter. Y

8. The process of clairn''wherein said hydrocracking zone of step (b) is a dense bed, liquid phase fiuidized catalytic hydrocrackingzone. f

12 9. lThe process of claim 6 wherein the catalyst maintained in the hydrogenation zone` of step (a) is a catalytic composite consisting essentially of a crushed, deactiyated hydrocracking catalyst recovered from the hydrocracking zone of step (b). l i l References (Jited in the le of this patent i UNITED STIK'IESV PATENTS Y Howard Feb. 19,1929

1,702,899 2,191,157 Pier et al. FebfZO, 1940 2,853,433 Keith 1 Sept. 23, 1958 2,913,397 Murray 'et al Nov. 1 7, 1959 3,018,241 Gorin Q 'Ian. 23, 1962 Gorin Jan. 23, 19,62

Claims (1)

1. AN IMPROVED PROCESS FOR PRODUCING LIQUID FUELS FROM ASH-CONTAINING COAL EXTRACT, SAID EXTRACT BEING ESSENTIALLY NON-DISTILLABLE WITHOUT DECOMPOSITION, AT LEAST A PORTION OF SAID EXTRACT BEING INSOLUBLE IN BENZENE AND AT LEAST A PORTION OF SAID ASH BEING BELOW 0.01 MICRON IN DIAMETER, WHICH PROCESS COMPRISES (A) SUBJECTING SAID ASH-CONTAINING COAL EXTRACT TO HYDROGENATION IN A HYDROGENATION ZONE MAINTAINED UNDER CONDITIONS SUCH THAT AN ASH-CONTAINING, NONDISTILLABLE HYDROCARBONACEOUS LIQUID COMPRISING AT LEAST 60 WEIGHT PERCENT OF THE COAL EXTRACT IS OBTAINED, SAID NON-DISTILLABLE LIQUID BEING MORE SOLUBLE IN BENZENE AND CONTAINING LESS ASH BELOW 0.01 MICRON IN DIAMETER THAN SAID COAL EXTRACT, AND (B) SUBJECTING AT LEAST A PORTION OF SAID NON-DISTILLABLE HYDROCARBONACEOUS LIQUID TO CATALYTIC HYDROCRAKING IN A HYDROCRACKING ZONE MAINTAINED UNDER CONDITIONS SUCH THAT AN ASH-FREE, BENZENE-SOLUBLE, DISTILLABLE HYDROCARBONACEOUS LIQUID IS OBTAINED.

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