US3607718A - Solvation and hydrogenation of coal in partially hydrogenated hydrocarbon solvents - Google Patents

Abstract

Coal is solubilized and hydrogenated in partially hydrogenated hydrocarbon streams such as clarified slurry oil to produce a nonviscous solution which is readily deashed by settling or filtering. Both inorganic sulfur and organically combined sulfur are removed, and the deashed solubilized coal thus produced has a very low sulfur content. The invention is also useful for producing a hydrogenated solubilized coal solution which is suitable for use as a feedstock for a petroleum refinery, and valuable liquid hydrocarbon distillate products boiling, for example, within the gasoline, kerosene, naphtha, light fuel oil and gas oil ranges may be produced therefrom.

Description

United States Patent 3,188,179 6/1965 Gorin [72] Inventors William M. Leaders; 208/10 Jack W. Roach, both of Oklahoma City, 3,488,279 1/1970 Schulman 208/10 Okl 3,514,394 5/l970 Wilson etal. 208/l PP;- 1,6899 1970 Primary Examiner-Delbert E. Gantz [22] He d 1971 Assistant Examiner-Veronica O'Keefe [45] i p AtlameyShanley and ONeil [73] Asslgnee Kerr-McGee Corporation Oklahoma City, Okla.

[54] SOLVATION AND HYDROGENATION 0F COAL W L R ENATED HY ROCARBON 0G D ABSTRACT: Coal is solubilized and hydrogenated in partially hydrogenated hydrocarbon streams such as clarified slurry oil 30 Claims, 2 Drawing Figs.

to produce a l'lOllVlSCOUS solution WhlCh ls readily deashed by US. ttling or filtcring inorganic ulfur and organically com- 208/8 bined sulfur are removed, and the deashed solubilized coal [51] Int. Cl ClOg 1/06 thus produced has a very low lf content. The invention is [50] Field of Search 208/ a|so f l f producing a hydrogenated solubilizedvcoal so|u 56 R f d tion which is suitable for use as a feedstock for a petroleum 1 e erences refinery, and valuable liquid hydrocarbon distillate products UNITED STATES PATENTS boiling, for example, within the gasoline, kerosene, naphtha, 2,464,271 3/1949 Storch et al 208/l0 light fuel oil and gas oil ranges may be produced therefrom.

45 46 44 sa slnoa V COAL MIXER H SOLUTIZER FlsrlER I f HEATER 24 28 8 l5 l7 I6 I 25 26 2| 29 x l8 49$) SOLVENT 36 PATENTED SEP21 I971 3.601718 sum 1 [IF 2 F l LTKfIR FIG. 1 A

:3 INVENTOR WILLIAM M. LEADERS JACK W. ROACH BY M'QW ATTORNEYS com.

SOLYENT SOLVATION AND HYDROGENATION OF COAL IN PARTIALLY HYDROGENATED HYDROCARBON SOLVENTS BACKGROUND OF THE INVENTION The potentially soluble substances in fossilized carbonaceous materials such as coal are composed largely of high molecular weight three-dimensional cyclic structures which contain predominantly six membered rings. For example, coal contains bitumen and humin which have large flat aromatic lamellar structures that differ in molecular size, degree of aromaticity, oxygen content, nitrogen content, and the degree of cross-linking. Coal also contains volatile matter, fusain, mineral matter, and moisture. The mineral matter remains behind as ash when the coal is burned, and fusain is a mineral charcoal which is consumed during burning at high temperatures in the presence of sufficient oxygen for complete combustion. Coal contains sulfur which is present as pyritic sulfur, inorganic sulfates and/or organic sulfur compounds. The presence of sulfur in substantial quantities results in contamination of the atmosphere with sulfur oxides upon combustion which, upon reaction with atmospheric moisture, produce highly corrosive sulfurous acid and/or sulfuric acid. The mineral content of the coal, which may be -15 percent or higher in many instances, reduces the B.t.u. value of the raw coal per unit weight and this results in increased transportation costs. There is an additional cost when the ash-containing coal is burned as the ash residue must be removed from the combustion zone and disposed of in some manner.

The presence of fusain, mineral matter, and sulfur in substantial quantities also reduces the value of the coal. If these substances are removed, the coal may be used for preparing high purity coke for specialized purposes, such as in anodes to be used in the production of aluminus. High purity coke for anodes has a much higher value than the impure coke produced from the original coal.

In view of the foregoing and for still other reasons, it is desirable to reduce the fusain, mineral matter, and sulfur content of coal. One process for removing these substances involves solvation of the solvent-soluble coal constituents including the bitumen and humin contents in an organic solvent, and then separating the insoluble fusain, mineral matter, and inorganic sulfur from the coal solution. This process is largely ineffective for the removal of organically combined sulfur as it is soluble in the solvent.

A wide variety of organic solvents have been employed for solubilizing coal. However, the solvents used heretofore have not been capable of indirectly hydrogenating the solubilized coal to the extent required to produce low boiling liquid products and it has been necessary to resort to direct hydrogenation with gaseous hydrogen. Direct hydrogenation requires high temperatures and pressures and the presence of a catalyst which tends to be poisoned by impurities in the coal. As a result, an economic method of hydrogenating and desulfurizing coal to produce a low sulfur synthetic crude petroleum has not been available heretofore.

SUMMARY OF THE INVENTION The present invention provides for the first time an entirely satisfactory process for simultaneously solubilizing and hydrogenating coal.

The invention further provides a process for hydrogenating coal which does not require a catalyst in the solvation vessel, or the use of extremely high over-pressures of hydrogen. The partial hydrogenation of the solvent is accomplished outside of the coal solvation vessel, and in the absence of substances which would poison or otherwise adversely affect the hydrogenation catalyst.

The invention further provides a process for solubilizing an unusually high percentage of the coal, and which maximizes the production of valuable liquid products and minimizes the production of low molecular weight gases and solid byproducts. It is possible to obtain a higher yield of the more valuable constituents of the coal, and a lower percentage is lost in processing.

The invention further provides for the substantially complete removal of the mineral ash constituents of the coal.

The invention further provides a greatly improved process for removing sulfur from coal, as both mineral sulfur and organically combined sulfur are removed. It is possible to reduce the sulfur content of the deashed solubilized coal to well below 0.5 percent by weight, and often below 0.1 percent by weight. Such low sulfur contents have not been achieved heretofore in prior art coal solubilization processes.

The invention further provides a continuous process for producing synthetic crude from coal, as the liquid products produced in accordance with the present invention are suitable for use as a feedstock to a prior art petroleum refinery. The used or dehydrogenated solvent may be recovered from the coal solution by fractionation, subjected to a partial hydrogenation step, and recycled in the process.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B of the drawings illustrate one presently preferred arrangement of apparatus for use in practicing the process of the invention. FIG. 1B is a continuation of FIG. 1A.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING PREFERRED VARIANTS THEREOF Referring now to the drawings, a partially hydrogenated hydrocarbon solvent to be defined more fully hereinafter is passed from storage vessel 10 to mixer 11 via conduit 12 at a rate controlled by valve 14. Finely divided coal in storage vessel 15 is also passed to mixer 11 via conduit 16 at a rate determined by meter l7. The relative feed rates of solvent and coal are controlled so that the weight ratio of solvent to coal in mixer 11 is between about l:l and 20:1, and preferably between 2:] and 5:1. The best results are usually obtained when the weight ratio of solvent to coal is approximately 3:1.

The coal and solvent in mixer 11 are agitated with a motor driven agitator l8, and the slurry thus prepared is passed to pump 19 via conduit 13, and then via conduit 20 to gas-fired heater 21. The slurry flowing in coil 22 is heated to an elevated temperature which preferably closely approximates the desired initial temperature of solvation, and the heated slurry is then withdrawn via conduit 23 and is passed to solutizer 24.

While it is not essential when using partially hydrogenated solvents, it is usually preferred to carry out the solvation in the presence of added gaseous hydrogen. When gaseous hydrogen is added, it may be passed into the slurry flowing in conduit 20 upon opening valve 25 in conduit 26.

The solutizer 24 preferably operates under a superatmospheric pressure which is determined by the overpressure of gaseous hydrogen when present, the vapor pressure of the solvent at the operating temperature, and/or the hydraulic pressure applied by pump 19. The solvation temperature is determined by the initial temperatures of the slurry in conduit 23 and by the temperature control fluid supplied to coil 27 at a rate controlled by valve 28 in conduit 29 and withdrawn via conduit 30. The solvent is contacted with the coal under the temperature and pressure conditions existing in solutizer 24 for a sufficient period of time to solubilize and hydrogenate a substantial amount of extractable carbonaceous material and to produce a solution which contains finely divided fusain, mineral ash, and other insoluble constituents.

The coal solution containing the insoluble constituents is withdrawn from solutizer 24 via conduit 31 and is passed to header 33 which is provided with a plurality of space outlets 34. The header 33 is positioned in ash separator 35 a substantial distance beneath the interface 36 between the relatively heavy sludge layer 37 and the lighter clarified coal solution 38. The sludge layer 37 contains mineral ash, fusain and other insoluble material, and it is withdrawn via conduit 39 at a rate controlled by valve 40. The sludge 37 is withdrawn at a rate to maintain the interface 36 substantially above the outlets 34 on header 33. Inasmuch as the coal solution flowing in conduit 31 is at an elevated temperature and has a low viscosity, the heavier insoluble material tends to settle out rapidly when it is passed into ash separator 35. While the mechanism is not fully understood at the present time, it is believed that injecting the solution into the heavy sludge layer 37 tends to agglomerate the micron size solid particles of insoluble material and larger particles are formed which settle even more rapidly. As a result, the lighter clarified phase 38 is substantially free of insoluble material and often it does not require filtering, and especially in instances where the entire deashed coal solution is to be used as a fuel.

The clarified coal solution 38 is withdrawn from the top of ash separator 35 via conduit 45 and, upon opening valve 46 and closing valves 47 and 49, it is passed via conduit 44 to coil 51 in heat exchanger 52. A coolant such as water is supplied to heat exchanger 52 via conduit 53 at a rate controlled by valve 54, and it is withdrawn therefrom via conduit 55. In instances where it is desired to filter the clarified coal solution for the purpose of removing additional insoluble material, valve 46 is closed and valves 47 and 49 are opened, and the clarified coal solution 38 is passed via conduits 45 and 48 to filter 56. The clarified and filtered coal solution is withdrawn via conduit 50 and is passed to conduit 44, and then to coil 51 in heat exchanger 52.

The coal solution may be cooled i heat exchanger 52 to any suitable desired temperature such as 75200 F. or higher, or to a temperature which is suitable for feeding to atmospheric distillation tower 57. The solution is withdrawn via conduit 58 at a rate controlled by reducing valve 59 and is passed into gas separator 60.

The gas separator 60 is partially filled with a liquid coal solution phase 61 which has a vapor space 62 thereabove. The coal solution flowing in conduit 58 contains excess hydrogen, hydrogen sulfide produced by desulfurization of the coal during the solvation step, hydrocarbon gases, and other gases which are released into the vapor space 62 upon reducing the pressure on the solution as it passes through reducing valve 59. The pressure existing within vapor space 62 may be, for example, from substantially atmospheric pressure to 1 or 2 atmospheres. The gases in vapor space 62 are withdrawn via conduit 63 at a rate controlled by valve 64. If desired, the gases may be passed to a sour gas processing step, the sulfur content recovered, and the hydrogen content recycled to conduit 26.

In instances where one or more light liquid fractions are not recovered from the coal solution, it may be withdrawn from gas separator 60 via conduit 68 upon closing valve 65 in conduit 66 and opening valve 67. The deashed, degassed and desulfurized coal solution withdrawn via conduit 68 is very useful as a fuel. Inasmuch as it is normally liquid at room temperature, it may be readily pumped and transported by pipeline.

In most instances, it is desirable to recover at least the gasoline fraction and the light gas oil fraction from the coal solution as these are valuable liquid products of commerce, and also a dehydrogenated solvent fraction for recycle in the process. This may be conveniently accomplished by closing valve 67 in conduit 68, opening valve 65 in conduit 66, and passing the deashed and degassed coal solution to atmospherical distillation tower 57.

As will be recognized by those skilled in this art, it is not necessary that ash separator 35, filter 56, and heat exchanger 52 be operated at approximately the same pressure as exists in solutizer 24. For example, pressure-reducing valve 59 may be relocated in conduit 31 and gas separator 60 relocated immediately after the valve 59, and in such instances the ash separator 35, filter 56 and heat exchanger 52 may be operated at approximately the same pressure as gas separator 60.

Atmospheric distillation tower 57 may be of a prior art type used in petroleum refining for producing a plurality of hydrocarbon streams from crude oil. The construction and operation of such combination atmospheric distillation towers is well known, and does not constitute a part of this invention. Distillation tower 57 may be operated, for example, to produce a stream of normally gaseous hydrocarbons which is withdrawn via conduit 69, a gasoline stream having a boiling point up to 430 F. which is withdrawn via conduit 70, a light gas oil stream having a boiling range of 430-700 F. which is withdrawn via conduit 71 for further refinery processing, and a residue or bottoms stream which is withdrawn via conduit 73. The gases withdrawn via conduit 69 may be used to fire heater 21 or for other fuel purposes; and the gasoline stream withdrawn via conduit 70 may be used for internal combustion engine fuel.

The bottoms fraction withdrawn via conduit 73 is passed to vacuum distillation tower 89. in that tower, a heavy gas oil fraction containing dehydrogenated solvent and having a boiling range of, for example, 560950 F. is withdrawn and passed via conduit to catalytic cracker unit 78 wherein it is cracked and fractionated into lighter products including, for example, a gasoline fraction which is withdrawn via conduit 79, as well as other conventional catalytic cracker products which are not shown. The bottom stream withdrawn from vacuum distillation tower 89 via conduit may be recycled in the process via conduits 97 and 82 for further thermal cracking and hydrogenation to produce lighter liquid products upon opening valve 96 and closing valve 98. It also may be withdrawn via conduit 99 upon closing valve 96 and opening valve 98 and used as a low sulfur fuel.

The bottoms product withdrawn via conduit 100 from catalytic cracker unit 78 and having a boiling range of from 700-900 F. consists of slurry oil produced in said catalytic cracker unit and dehydrogenated recycle solvent. The bottoms product is passed to clarifier 101, from which sludge is removed via conduit 104, and then passed via conduit 102 at a rate controlled by valve 103 to hydrogenation unit 80.

If required, makeup solvent may be introduced via conduit 106 into conduit 102 at a rate controlled by valve 107'. Further, if excess solvent is flowing in conduit 102, it may be conveniently removed via conduit 106 at a rate controlled by valve 107. Such makeup solvent as is required is usually a small percentage of that flowing through the system such as ll0 percent, and is usually approximately 5-6 percent. Hydrogen is fed via conduit 108 at a rate controlled by valve 109 into hydrogenation unit 80. The partially hydrogenated solvent is then withdrawn via conduit 82 and is passed to solvent storage 10 for reuse in the process.

The carbonaceous material that is solubilized may be coal, which preferably is of a rank lower than anthracite, such as subanthracite, bituminous, subbituminous, and lignite or brown coal. Peat also may be used. The particles size of the coal may vary over wide ranges and in general the particles need only be sufficiently small to be slurried in the solvent and pumped. For instance, the coal may have an average particle size of onefourth inch in diameter or larger in some instances, and as small as minus 200 mesh (Tyler Screen) or smaller. The most practical particle size is often between minus 30 mesh and minus 100 mesh as less energy is required for grinding and yet the particles are sufficiently small to achieve an optimum rate of solubilization. The particle size is not of great importance provided extremely large particles are not present as the solvent penetrates the coal particles rapidly. The carbonaceous material that is hydrogenated in accordance with the invention is derived from coal, i.e., it may be coal, solubilized coal which is dissolved in a solvent other than the partially hydrogenated hydrocarbon solvent, solid deashed coal prepared by a prior art deashing process, partially hydrogenated coal which is being recycled, etc.

A partially hydrogenated hydrocarbon solvent is employed that has been subjected to a partial hydrogenation step prior to intimately contacting it which the particulate coal and/or carbonaceous material derived therefrom. The hydrocarbon solvent contains polycyclic hydrocarbons having normal boil ing points of about 425l000 F. and at least two condensed benzene rings before the partial hydrogenation step, and after partial hydrogenation, it contains polycyclic hydrocarbons wherein at least one of the said condensed benzene rings is retained and hydrogen is added during the partial hydrogenation to at least one condensed benzene ring adjacent thereto. Thus, the partially hydrogenated hydrocarbon solvent contains polycyclic hydrocarbons having an aromatic-naphthenic used ring structure wherein a benzenoid ring and a nonbenzenoid or naphthenic ring adjacent thereto are fused. It is understood that still other naphthenic or benzenoid rings may be present in the polycyclic hydrocarbon molecule, and they may be either fused to the foregoing two minimum rings or they may be located in other portions of the molecule. The solvent preferably contains polycyclic hydrocarbons having about 2-4 benzene rings before partial hydrogenation, and at least one of the benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during the partial hydrogenation step.

The solvent to be partially hydrogenated may be a byproduct stream produced in normal petroleum refinery operations having a boiling range of about 430-1000 F., e.g., a catalytic cracker recycle stock such as light recycle catalytic cracker oil, heavy recycle catalytic cracker oil and clarified catalytic cracker slurry oil, thermally cracked petroleum stocks, and lubricating oil aromatic extracts such as bright stock phenol extract. The boiling range of the byproduct petroleum stream is preferably between about 600 and 1000 F., and should be about 700-900 F. for better results in most instances. Refractory highly aromatic streams wherein the aromatic constituents contain two or more fused benzene rings per molecule and make up at least 50 percent by weight of the solvent are preferred, and for better results the aromatic constituents should be present in an amount of at least 80-95 percent by weight. Clarified catalytic cracker slurry oil is an excellent solvent.

The amount of hydrogen that is added to the solvent during the partial hydrogenation step should be sufficient to hydrogenate a substantial number of the fused benzene rings in the polycyclic hydrocarbon content, but insufficient to hydrogenate all of the fused benzene rings. For instance, when the polycyclic hydrocarbons have about 2-4 condensed benzene rings before partial hydrogenation, at least one of the benzene rings is retained in the molecule and 1-3 benzene rings may be hydrogenated to produce naphthenic rings during the partial hydrogenation step. As a general rule, approximately 100-1000, and preferably about 200-700 standard cubic feet of hydrogen per barrel of solvent added, but smaller or larger amounts of hydrogen may be added depending on the desired degree of hydrogenation and the number of fused benzene rings which are present. In instances where the solvent is clarified catalytic cracker slurry oil, it is usually preferred that approximately 400-500 standard cubic feed of hydrogen per barrel of slurry oil be added during the partial hydrogenation step.

Prior art hydrogenation catalysts may be employed such as a mixed nickel-molybdenum catalyst. Also, the prior art temperature and pressures for such hydrogenation reactions may be employed, e.g., a hydrogen pressure of about 100-1000 p.s.i.g. and a temperature of about 400-800 F. The pressure is preferably about 200-500 p.s.i.g. and the temperature approximately 550-650 F. As a general rule, the hydrogenation is usually continued until approximately 50 percent of the ethylenic double bonds contained in the solvent have been saturated or until a quantity of hydrogen such as discussed above has been added.

The presence of added elemental hydrogen is not always necessary, but it is usually beneficial and aids in more rapid and complete solubilization and/or hydrogenation. In a continuous process, the feed may include 0.1-2 percent and preferably 0.25-1 percent by weight of hydrogen based upon the weight of coal or carbonaceous material derived therefrom. The excess hydrogen which does not enter into the solubilization and/or hydrogenation reaction may be recovered from the coal solution and recycled if desired, and thus higher percentages than 2 percent by weight may be used such as up to 5 percent weight. The hydrogen content of the vapor phase in contact with the liquid solvent phase may be 5-50 percent and is preferably about 10-35 percent by volume, but may be higher or lower. However, the higher the partial pressure of hydrogen, the faster the solubilization and/or hydrogenation reaction as more hydrogen is available in the solvent.

The temperature should be sufficiently high to result in a fast solvation and/or hydrogenation rate. The upper limit is the temperature at which the coal and/or carbonaceous material derived therefrom is coked and/or the organic solvent is decomposed. The temperature may be about 550-l0 00 F., and preferably is at least 650 F. to 700 F. In most instances, the temperature should be about 650-900 F. and, for best results, about 700-850 F The solvation temperature should not be sufficiently high to result in substantial coking within the period of treatment. The coking temperature varies from coal to coal, and usually coals having a higher rank also have a higher decomposition or coking temperature. Oklahoma bituminous coal usually cokes at about 800-840 F., and more highly volatile coals such as the Wyoming coals usually coke at lower temperatures. In instances where a tubular reactor is employed and a slurry of coal in the solvent is passed through the tubes on a continuous basis, somewhat higher temperatures may be employed due to the dynamic nature of the system. Also, rate of flow through the tubes is sufficiently fast to reduce coking on the tube surfaces.

The solvent is contacted with the coal and/or carbonaceous material derived therefrom for a sufficient period of time to solubilize and/or hydrogenate a substantial amount of the extractable material in the coal. For example, the solvent may be contacted with the coal over about 0.1-2 hours. The contact period should not be more than about 0.2-1 hour for economic reasons; and is preferably 0.25-0.5 hour.

The weight ratio of solvent to coal and/or carbonaceous material derived therefrom may vary over wide ranges. The minimum weight ratio of solvent to coal and/or carbonaceous material derived therefrom for effecting a worthwhile amount of hydrogenation is about 0.2: l and the upper limit is practical in nature and may be up to about 20: 1. The minimum ratio of solvent to coal for solvation is usually about 1:1 or 2:1 and the upper limit may be as high as 15:1 or 20:1. There is little improvement in the degree of extraction beyond solvent to coal weight ratios of 5:1 or 10:1, and as the cost of handling the solvent increases with the amount used per unit weight of coal, the lowest ratio necessary to give a desired degree of extraction is preferred. Usually, this is a solvent to coal weight ratio between about 2:1 and 5: 1.

The pressure in solutizer 24 is at least sufficient to maintain liquid phase conditions and it may be as high as 10,000 pounds per square inch absolute (p.s.i.a.), and is preferably about 1,000-5,000 p.s.i.a. for most solvents. The pressure should be sufficient to provide a solvent density of at least 0.5 g./cc. and preferably at least 0.6 g./cc. There is no upper limit on the solvent density within the foregoing pressure range as the highest solvent density that can be achieved under practical operating conditions is usually more satisfactory. The solvents defined herein have a solvent density of about 0.5-0.9 g./cc., and preferably about 0.6-0.7 g./cc., under the practical temperature and pressure conditions.

The pressure on the system is not important in the absence of a hydrogen overpressure provided the solvent has the necessary minimum density. 1f the solvent density is too low, then it is necessary to resort to pressure to increase the density. Usually pressurized hydrogen is preferred as a pressurizing medium, but other gases or gaseous mixtures may be employed. Also, the pressure may be imposed by suitable hydrostatic means such as a high pressure pump.

The coal solution produced in accordance with the invention may be separated from the undissolved mineral ash, fusain and other insoluble constituents following prior art practices. For instance, it is possible to allow the coal solution to settle for a suitable period of time such as %l hour in separator 35 under the conditions of solubilization, and then withdraw the heavy phase 37 containing the undissolved material in the form of a slurry or liquid-appearing phase. It is also possible to filter the solution and remove the ash constituents, or the ash constituents may be separated by centrifuging.

The process of the invention is very flexible and is capable of producing a liquid coal solution which is suitable for use as a bunker fuel without the need for preheating, a semisolid to solid coal which is liquefiable upon heating with steam and also may be used as a heavy fuel oil such as bunker fuel, or a friable coal product that may be used as a solid fuel in the same manner as conventional coal. For instance, the solution withdrawn from gas separator 60 via conduit 68 is normally liquid at room temperature and does not require heating for pumping, and the product withdrawn from vacuum distillation tower 89 via conduit 95 may be substantially free of distillate fractions and may be a friable solid when cooled to room temperature. In all instances, the products produced by the process of the invention are deashed, and generally are reduced in sulfur content to low levels, such as 0. l-l percent by weight.

The invention is also unique in its ability to convert a large percentage of the raw coal into light distillate hydrocarbon fractions which are suitable for use as fuel for internal combustion engines or light heating oils. After removal of the light distillable fractions and heavy gas oil containing dehydrogenated solvent from the coal solution, the higher boiling fraction may be recycled for additional hydrogenation and/or thermal cracking to lighter fractions. When desired, substantially all of the coal that is solubilized may be converted into usable light distillate fractions and this may be accomplished without the need for unusually high pressure anywhere in the system. Also, catalyst poisoning is not a problem due to the hydrogenation of distillate fractions which contain substantially no metal compounds and very little sulfur.

The dehydrogenated hydrocarbon solvent may be recovered as a distillate fraction and, after partial hydrogenation, is recycled indefinitely. The make up solvent that is required is usually approximately -10 percent by weight of the solvent flowing through the system. The make up solvent can be obtained from the high boiling liquid fractions that are produced and the process is capable of being self-sufficient insofar as the solvent requirements are concerned.

As a general rule, the amount of partially hydrogenated hydrocarbon solvent that is required for hydrogenating a previously solubilized or deashed coal fraction is substantially less than that required for both salvation and hydrogenation of the raw coal. When the coal has been previously solubilized or deashed, usually about 0.23 parts by weight of the solvent for each part by weight of the deashed coal is sufficient to achieve a satisfactory degree of hydrogenation. lt is understood that the degree of hydrogenation varies with the amount of available hydrogen in the partial hydrogenated hydrocarbon solvent. By varying the amount of hydrogen that is added to each barrel of the solvent in the partial hydrogenation step and/or the ratio by weight of solvent to coal, the amount of coal that is converted to light distillable fractions may be controlled to some extent.

in instances where a previously deashed solid coal is used as a feedstock, it is merely substituted for the raw coal in vessel 15. In instances where a solution of previously deashed coal in a solvent other than the partially hydrogenated hydrocarbon solvent is used as a feedstock, the solution may also be fed to vessel and the required amount of partially hydrogenated hydrocarbon solvent is added thereto in mixer 1]. in each instance, the remainder of the process may be as previously described for raw coal with the exception of there being no need for withdrawing a heavy phase 37 from ash separator 35.

The following examples further illustrate the process of the invention.

EXAMPLE! This example illustrates the preparation of a partially hydrogenated hydrocarbon solvent for use in practicing the invention.

The feedstock was a clarified catalytic cracker slurry oil which was produced in normal petroleum refinery operations. The slurry oil had a distillation range of 700l ,000 F. and an AP! gravity of2. l.

The slurry oil was partially hydrogenated in a laboratory rocking autoclave at a temperature of 600 F. and under a hydrogen pressure of 500 p.s.i.g. in the presence of a mixed nickel-molybdenum hydrogenation catalyst. The hydrogenation was continued until hydrogen was consumed in an amount equivalent to 600 standard cubic feet per barrel of the slurry oil charge stock. The hydrogenation was terminated, the partially hydrogenated slurry oil was recovered and analyzed, and the analysis was compared with that of the charge stock. The following data was obtained:

The partially hydrogenated slurry oil produced in accordance with this example was used in example ll.

EXAMPLE ll This example illustrates the solvation and hydrogenation of a subbituminous Wyoming coal using the partially hydrogenated slurry oil produced in accordance with example I as a solvent and indirect hydrogenating agent.

The pressure vessel was a 1 liter Paar autoclave which was provided with a valved conduit for withdrawing a heavy phase from the lower end, a valved conduit for withdrawing a light phase from the upper end, and a pressure gauge. The autoclave was charged with 730 grams of a slurry containing in part by weight of the dry coal ground to minus 65 mesh and three parts by weight of the partially hydrogenated slurry oil. The autoclave was then pressurized with gaseous hydrogen to 500 p.s.i.g., and the temperature was raised to 700 F. These conditions were maintained for one-half hour, during which time about percent of the extractable carbonaceous matter in the coal was solubilized, and then the solution was cooled to F. and filtered to remove the undissolved residue. The undissolved residue was collected and analyzed, and the analysis was compared with that for the initial coal. The results appear below in table ll.

TABLE ll Volatile Matter Fixed Carbon Material wt. 96 Ash, wt. 70 wt. it:

initial coal 45.8 6.6 47.6 Undissolved coal residue 14.1 60.1 25.8

The data in table Ill show that the coal was hydrogenated to produce approximately one-third by weight of hydrocarbons boiling in the gasoline range (up to 430 F.), one-third by weight of hydrocarbons boiling in the light gas-oil range (430700 F.), and one-third by weight of higher boiling hydrocarbon products.

An analysis of the distillate fractions showed the sulfur content to be less than 0.1 percent, as compared with approximately 0.8-0.9 sulfur in the initial coal. Thus, the process is effective for the removal of both mineral sulfur and organic sulfur. The analysis of the fraction boiling at 700l ,000 F. gave the following results:

Carbon, wt. 91.7 Hydrogen, wt. 8.2 Sulfur, wt. less than 0.1 Gravity, +APl 2.4

The above analysis is substantially the same as that for the clarified slurry oil before it was partially hydrogenated in accordance with example I. This demonstrates that the hydrogen added to the slurry oil in the partial hydrogenation step of example was transferred to the coal during the solvation and hydrogenation step of this example.

The fraction distilling at 700l,000 F. may be partially hydrogenated in accordance with example l and reused as a solvent.

EXAMPLE III This example illustrates the solvation of coal when employing the apparatus shown in FIGS. 1A and 1B of the drawings.

Dry Oklahoma bituminous coal (Stigler Seam, Evans Coal Company) having a particle size of minus 65 mesh and partially hydrogenated clarified catalytic cracker slurry oil having a boiling range before hydrogenation of 700-900 F. are fed to mixer 11 at feed rates to provide three parts by weight of the slurry oil for each part by weight of the coal. The suspension of coal in the solvent is passed to pump 19 via conduit 13, and then via conduit 20 to heating coil 22 in heater 21 where the temperature is raised to 750 F. Elemental hydrogen in an amount of 0.5 part by weight based upon the weight of the coal is added via conduit 26 to the suspension flowing in conduit 20.

The heated hydrogen-containing slurry is withdrawn via conduit 23, and is passed to solutizer 24 which is a tube still operating at a pressure of 1,5000 p.s.i.g., at a feed rate to provide a residence time of minutes. A heating fluid is supplied to coil 27 to maintain a temperature of 750 F. in solutizer 24 during the 30 minutes residence time therein during which approximately 95 percent by weight of the carbonaceous matter in the coal is solubilized. Coal solution containing suspended micron size particles or mineral ash, fusain and other insoluble constituents is withdrawn as a fluid phase via conduit 31, and is passed to header 33 in ash separator 35. The header 33 is positioned below the surface 36 of sludge layer 37 whereby the micron size particles of insoluble constituents are agglomerated as the coal solution is ejected via outlets 34. The average residence time for the solution in ash separator is 30 minutes, and this is sufficient time to allow substantially all of the insoluble constituents to be agglomerated and retained in the heavy sludge layer 37. The sludge layer 37 is withdrawn via conduit 39 as a fluid phase at a rate sufficient to maintain the interface 36 at the level illustrated in the drawing.

The lighter clarified phase 38 of coal solution in the upper section of ash separator 35 contains very small amounts of micron size insoluble material, and this is removed by passing thecoal solution to filter 56 via conduits 45 and 48. The clarified and filtered coal solution is withdrawn via conduit 50 and is passed via conduit 44 to heat exchanger 52 where the temperature is reduced to below the boiling point of gasoline, and the cooled solution is passed to gas separator 60 via conduit 58. The pressure in gas separator 60 is about 1 to 2 atmospheres. Excess hydrogen and gases produced during the solvation are withdrawn via conduit 63 and the degassed coal solution is passed to atmospheric distillation tower 57 via conduit 66.

A light or normally gaseous hydrocarbon fraction is withdrawn from distillation tower 57 via conduit 69 and is used as fuel in the process such as in heater 21 and for other heating purposes. A gasoline fraction is withdrawn via conduit 70 for sale as motor fuel and a light gas oil fraction is withdrawn via conduit 71 for subsequent refinery processing. The bottoms fraction from distillation tower 57 is passed to vacuum distillation tower 89 via conduit 73 and a heavy gas oil containing dehydrogenated solvent is separated therefrom via conduit and is passed to catalytic cracker unit 78. The heavy gas oil fraction is cracked to produce lighter products, including gasoline, for subsequent processing or for sale.

A slurry oil fraction is withdrawn from catalytic cracker unit 78 via conduit 100, passed to clarifier 101 where a clarified slurry oil fraction is prepared, and the clarified slurry oil is withdrawn via conduit 102 and is passed to hydrogenation unit 80. Makeup solvent, which is clarified catalytic cracker slurry oil having a boiling range of 700900 F., is supplied to conduit 102 via conduit 106 in an amount of about 6 percent by weight of the solvent flowing through the system. Hydrogen is fed via conduit 108 and is introduced into the hydrogenation unit 80 at a rate to provide 400 standard cubic feet of hydrogen per barrel in the partially hydrogenated slurry oil that is withdrawn via conduit 82.

The bottoms fraction from vacuum distillation tower 89 is passed to conduit 82 via conduits and 97 for recycle in the process where it is subjected to additional hydrogenation and thermal cracking to produce lighter hydrocarbon fractions. When desired, a portion or all of the bottoms from distillation tower 89 may be withdrawn via conduits 95 and 99 and may be used as a low sulfur fuel.

EXAMPLE IV This example illustrates the hydrogenation of carbonaceous material which was previously derived from coal by solubilization in a solvent other than the partially hydrogenated hydrocarbon solvent of the invention. The pressure vessel emgloyed in this example was the same as that used in example ll.

The autoclave was partially filled with 540 grams of pyridine and grams of minus 65 mesh dry Oklahoma bituminous coal which had a sulfur content of approximately 2 percent and a mineral ash content of approximately 11 per cent. The autoclave was sealed, the air was evacuated from the vapor space above the charge, and the vapor space was pressurized with hydrogen gas to an initial hydrogen pressure of 750 p.s.i.g. The sealed autoclave was heated and agitated in a rocking heater to provide a solvent temperature of 640 680 F., and the pressure rose rapidly to a maximum pressure of 4,800 p.s.i.g. The heating and agitation was continued for 1 hour, and then the solution was allowed to settle for 30 minutes. The heavy phase, which was a fluid slurry of undissolved coal, ash and a small amount of the dissolved coal in pyridine, was withdrawn by opening the valve in the conduit leading from the bottom of the autoclave. The solution of coal remaining after removing the slurry contained approximately 1 percent by weight of sulfur and about 0.2 percent by weight of ash. Under these conditions, 49 percent by weight of the coal was dissolved in the pyridine solvent, and it was recovered as a friable solid by evaporation of the pyridine.

Deashed and desulfurized coal prepared by the above process is admixed with three parts by weight of the partially hydrogenated clarified slurry oil produced in accordance with example I, and the autoclave is charged with 700 grams of the mixture. The autoclave is sealed, and the temperature is raised to 700 F. by heating and agitating in the rocking heater. The pressure in the autoclave is 1,500 p.s.i.g. The heating and agitation is continued for one-half hour. The fluid solution is withdrawn from the autoclave and upon fractional distillation, approximately one-third by weight of the deashed coal charge is obtained as liquid hydrocarbons boiling within the light gas oil range. The sulfur contents of the gasoline and light gas oil fractions are less than about 0.1 percent and about 0.3 percent by weight, respectively.

EXAMPLE V This example illustrates the hydrogenation of a solution of solubilized coal in a solvent other than the partially hydrogenated hydrocarbon solvent of the present invention. The autoclave employed in this example is the same as that described in example ll.

The general procedure of example 1V is repeated with the exception of substituting the clarified slurry oil described in example 1 for the pyridine as a solvent. The slurry oil is not partially hydrogenated, and it is used as a solvent in this example as produced in the refinery operation. The hydrogen overpressure is 750 p.s.i.g., the maximum pressure employed is 1,750 p.s.i., and the solvation temperature is 750 F. The au toclave is heated and agitated under these conditions for 1 hour, and then the coal solution is allowed to settle for onehalf hour. The settled ash and other insoluble constituents are removed leaving a solution of solubilized coal in the slurry oil. Approximately 80 percent by weight of the coal is dissolved.

Upon removal of one-half of the solution from the autoclave and evaporation of the solvent under reduced pressure, it is found that substantially no light distillate fraction is present. The deashed coal is a hard and friable solid after removal of the solvent.

Three parts by weight of the partially hydrogenated slurry oil solvent prepared in accordance with example 1, based upon the weight of coal dissolved in the solution remaining in the autoclave, is added and the autoclave is closed. The autoclave is agitated and heated at 750 F. for an additional hour at a pressure of 1,500 p.s.i.g., and then cooled to room temperature. The coal solution is very fluid and it is apparent that a substantial degree of hydrogenation occurs. Upon subjecting the hydrogenated coal solution to fractional distillation, it is found that at least one-third of the initial weight of solubilized coal is converted to a light distillate boiling within the gasoline range, and an additional one-third is converted to a heavier distillate boiling within the light gas oil range. Thus, it is possible to add the partially hydrogenated hydrocarbon solvent to a solution of unhydrogenated coal in another solvent, and then partially hydrogenate the solubilized coal and produce light distillate fractions without first recovering the deashed coal.

What is claimed is:

l. A process for hydrogenating feedstock including coal and carbonaceous material derived therefrom comprising subjecting said feedstock to a temperature of about 5501,000 F. in the presence of a partially hydrogenated hydrocarbon solvent selected from the group consisting of partially hydrogenated catalytic cracker recycle stocks, thermally cracked stocks, and lubricating oil aromatic extracts whereby hydrogen is released by the solvent and the carbonaceous material is hydrogenated, the hydrocarbon solvent containing a mixture of polycyclic hydrocarbons having normal boiling points of about 4251,000 F. and at least two condensed benzene rings before partial hydrogenation, and the partially hydrogenated hydrocarbon solvent containing polycyclic hydrocarbons wherein at least one of the said condensed benzene rings is retained and hydrogen is added to at least one condensed benzene ring adjacent thereto during the partial hydrogenation.

2. The process of claim 1 wherein the feedstock to be hydrogenated is prepared by solubilizing coal in a solvent other than the partially hydrogenated hydrocarbon solvent, and thereafter the solubilized coal is hydrogenated in the presence of the partially hydrogenated hydrocarbon solvent.

3. The process of claim 1 wherein each part by weight of the feedstock is hydrogenated in the presence of about 02-20 parts by weight of the partially hydrogenated hydrocarbon solvent.

4. The process of claim 1 wherein the feedstock is subjected to a temperature of about 650900 F. in the presence of the partially hydrogenated hydrocarbon solvent.

5. The process of claim 1 wherein the hydrocarbon solvent contains polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation, and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation.

6. The process of claim 1 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.

7. The process of claim 1 wherein each part by weight of the feedstock is subjected to a temperature of about 650-900 F. in the presence of about 02-20 parts by weight of the partially hydrogenated hydrocarbon solvent.

8. The process of claim 7 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.

9. The process of claim 8 wherein each part by weight of the feedstock is subjected to a temperature of about 700-850 F. in the presence of about 25 parts by weight of the partially hydrogenated catalytic cracker slurry oil.

10. The process of claim 1 wherein at least one light distillate fraction is separated from the hydrogenated feedstock subsequent to the hydrogenation step.

11. The process of claim 10 wherein at least one distillate fraction heavier than the said light fraction is subsequently separated from the hydrogenated feedstock, said heavier distillate fraction containing heavy gas oil and dehydrogenated hydrocarbon solvent, and said heavier distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker recycle stock.

12. The process of claim ll wherein the catalytic cracker recycle stock is subjected to partial hydrogenation, and the partially hydrogenated catalytic cracker recycle stock thus prepared is used as a partially hydrogenated hydrocarbon solvent to hydrogenate additional feedstock.

13. The process of claim 1 wherein the hydrocarbon solvent contains a mixture of polycyclic hydrocarbons having about 24 condensed benzene rings before partial hydrogenation and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation, each part by weight of the feed stock is subjected to a temperature of about 650900 F. in the presence of about 02-20 parts by weight of the partially hydrogenated hydrocarbon solvent, and at least one light distillate fraction and at least one heavier distillate fraction are separated from the hydrogenated feedstock, said heavier distillate fraction containing gas oil and dehydrogenated hydrocarbon solvent.

14. The process of claim 13 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.

15. The process of claim 14 wherein said heavier distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker slurry oil, and the catalytic cracker slurry oil thus produced is partially hydrogenated and used as a partially hydrogenated hydrocarbon solvent to hydrogenate additional feedstock.

16. A process for hydrogenating and deashing coal comprising intimately contacting the coal in particulate form with a partially hydrogenated hydrocarbon solvent selected from the group consisting of partially hydrogenated catalytic cracker recycle stocks, thermally cracked stocks, and lubricating oil aromatic extracts to produce a solution containing solubilized hydrogenated coal and suspended insoluble material including ash, the partially hydrogenated hydrocarbon solvent being contacted with the coal at a temperature of about 550-1,000 F. and at a solvent density of at least 0.5 g./cc., whereby hydrogen is released and the coal is solubilized therein and hydrogenated, the hydrocarbon solvent being subjected to partial hydrogenation prior to contacting it with the coal, the hydrocarbon solvent containing a mixture of polycyclic hydrocarbons having normal boiling points of about 425- l,000 F. and at least two condensed benzene rings before the partial hydrogenation thereof, the partially hydrogenated hydrocarbon solvent containing a mixture of polycyclic hydrocarbons wherein at least one of the said condensed benzene rings is retained and hydrogen is added to at least one of the said condensed benzene rings adjacent thereto, and separating the insoluble material from the hydrogenated coal solution.

17. The process of claim 16 wherein the partially hydrogenated hydrocarbon solvent is contacted with the coal in the presence of elemental hydrogen.

18. The process of claim 16 wherein each part by weight of the coal is contacted with about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent.

19. The process of claim 16 wherein the coal is contacted with the partially hydrogenated hydrocarbon solvent at a temperature of at least 650 F.

20. The process of claim 16 wherein the hydrocarbon solvent contains a mixture of polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation, and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation.

21. The process of claim 16 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.

22. The process of claim 16 wherein each part by weight of the coal is contacted in the presence of elemental hydrogen at a temperature of at least 650 F. with about 02-20 parts by weight of the partially hydrogenated hydrocarbon solvent for about 0.1-2 hours.

23. The process of claim 22 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.

24. The process of claim 23 wherein each part by weight of the coal is contacted with about 2-5 parts by weight of the partially hydrogenated catalytic cracker slurry oil in the presence of elemental hydrogen at a temperature of about 700-850 F. and the solvent density is at least 0.6 g./cc.

25. The process of claim 16 wherein at least one light distillate fraction is separated from the hydrogenated coal solution.

26. The process of claim 25 wherein at least one distillate fraction heavier than said light fraction is subsequently separated from the hydrogenated coal solution, said heavier fraction containing heavy gas oil and dehydrogenated hydrocarbon solvent, and said heavy distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker recycle stock.

27. The process of claim 26 wherein the catalytic cracker recycle stock is subjected to partial hydrogenation, and the partially hydrogenated catalytic cracker recycle stock thus prepared is used as a partially hydrogenated hydrocarbon solvent to solubilize and hydrogenate additional coal.

28. The process of claim 16 wherein the hydrocarbon solvent contains a mixture of polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation and at least one of said benzene rings is retained and l-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation, each part by weight of the coal is contacted for about 0.1-2 hours with about O.220 parts by weight of the partially hydrogenated hydrocarbon solvent in the presence of elemental hydrogen and at a temperature of at least 650 F., the solvent density is at least 0.6 g./cc. and at least one light distillate fraction and at least one heavier distillate fraction are separated from the solution of hydrogenated coal, said heavier distillate fraction containing gas oil and dehydrogenated hydrocarbon solvent.

29. The process of claim 28 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.

30. The process of claim 29 wherein each part by weight of the coal is contacted with about 2-5 parts by weight of the partially hydrogenated catalytic cracker slurry oil, said heavier distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker slurry oil, and the catalytic cracker slurry oil thus produced is partially hydrogenated and used to solubilize and hydrogenate additional coal.

, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,607,718 Dated September 1. 7

Inventor(s) William M. Leaders; Jack'W. Roach It 'is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 35, "aluminus" should read aluminum Column 3, line 27, "i" should read in Column 4-, line 32, "recycle" should read recycled lines 48 and 49, "su-" should read suband "banthracite" should read anthracite Column 5, line 4-9, before "added" insert is line 54, "feed" should read feet Column 6, lines 14 and l5, "l0" and "00 F." should read Column 7, line 29, "distillable" should read distillate line 58, "partial" should read partially line 62, "distillable" should read distillate Column 9, in the last line of the second table appearing therein, "Gravity, i-API" should read Gravity, API

line 61, 1,5000" should read 1,500

Column 10, line 57, loyed" should read ployed Signed and sealed this 25th day of April 5972 (SEAL IEDL IARD I IQFLJETCHJTR, JR. R BERT GGTTSCHALK flttosting Oif'ice-I' Commissionerof Patents

Claims (29)

1. 2. The process of claim 1 wherein the feedstock to be hydrogenated is prepared by solubilizing coal in a solvent other than the partially hydrogenated hydrocarbon solvent, and thereafter the solubilized coal is hydrogenated in the presence of the partially hydrogenated hydrocarbon solvent.
2. 3. The process of claim 1 wherein each part by weight of the feedstock is hydrogenated in the presence of about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent.
3. 4. The process of claim 1 wherein the feedstock is subjected to a temperature of aboUt 650*-900* F. in the presence of the partially hydrogenated hydrocarbon solvent.
4. 5. The process of claim 1 wherein the hydrocarbon solvent contains polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation, and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation.
5. 6. The process of claim 1 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.
6. 7. The process of claim 1 wherein each part by weight of the feedstock is subjected to a temperature of about 650*-900* F. in the presence of about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent.
7. 8. The process of claim 7 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.
8. 9. The process of claim 8 wherein each part by weight of the feedstock is subjected to a temperature of about 700*-850* F. in the presence of about 2-5 parts by weight of the partially hydrogenated catalytic cracker slurry oil.
9. 10. The process of claim 1 wherein at least one light distillate fraction is separated from the hydrogenated feedstock subsequent to the hydrogenation step.
10. 11. The process of claim 10 wherein at least one distillate fraction heavier than the said light fraction is subsequently separated from the hydrogenated feedstock, said heavier distillate fraction containing heavy gas oil and dehydrogenated hydrocarbon solvent, and said heavier distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker recycle stock.
11. 12. The process of claim 11 wherein the catalytic cracker recycle stock is subjected to partial hydrogenation, and the partially hydrogenated catalytic cracker recycle stock thus prepared is used as a partially hydrogenated hydrocarbon solvent to hydrogenate additional feedstock.
12. 13. The process of claim 1 wherein the hydrocarbon solvent contains a mixture of polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation, each part by weight of the feedstock is subjected to a temperature of about 650*-900* F. in the presence of about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent, and at least one light distillate fraction and at least one heavier distillate fraction are separated from the hydrogenated feedstock, said heavier distillate fraction containing gas oil and dehydrogenated hydrocarbon solvent.
13. 14. The process of claim 13 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.
14. 15. The process of claim 14 wherein said heavier distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker slurry oil, and the catalytic cracker slurry oil thus produced is partially hydrogenated and used as a partially hydrogenated hydrocarbon solvent to hydrogenate additional feedstock.
15. 16. A process for hydrogenating and deashing coal comprising intimately contacting the coal in particulate form with a partially hydrogenated hydrocarbon solvent selected from the group consisting of partially hydrogenated catalytic cracker recycle stocks, thermally cracked stocks, and lubricating oil aromatic extracts to produce a solution containing solubilized hydrogenated coal and suspended insoluble material including ash, the partially hydrogenated hydrocarbon solvent being contacted with the coal at a temperature of about 550*-1,000* F. and at a solvent density of at least 0.5 g./cc., whereby hydrogen is released and the coal is solubilized therein and hydrogenated, the hydrocarbon solvent being subjected to partial hydrogenation prior to contacting it with the coal, the hydrocarbon solvent containing a mixture of polycyclic hydrocarbons having normal boiling points of about 425*-1,000* F. and at least two condensed benzene rings before the partial hydrogenation thereof, the partially hydrogenated hydrocarbon solvent containing a mixture of polycyclic hydrocarbons wherein at least one of the said condensed benzene rings is retained and hydrogen is added to at least one of the said condensed benzene rings adjacent thereto, and separating the insoluble material from the hydrogenated coal solution.
16. 17. The process of claim 16 wherein the partially hydrogenated hydrocarbon solvent is contacted with the coal in the presence of elemental hydrogen.
17. 18. The process of claim 16 wherein each part by weight of the coal is contacted with about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent.
18. 19. The process of claim 16 wherein the coal is contacted with the partially hydrogenated hydrocarbon solvent at a temperature of at least 650* F.
19. 20. The process of claim 16 wherein the hydrocarbon solvent contains a mixture of polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation, and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation.
20. 21. The process of claim 16 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.
21. 22. The process of claim 16 wherein each part by weight of the coal is contacted in the presence of elemental hydrogen at a temperature of at least 650* F. with about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent for about 0.1-2 hours.
22. 23. The process of claim 22 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.
23. 24. The process of claim 23 wherein each part by weight of the coal is contacted with about 2-5 parts by weight of the partially hydrogenated catalytic cracker slurry oil in the presence of elemental hydrogen at a temperature of about 700*-850* F. and the solvent density is at least 0.6 g./cc.
24. 25. The process of claim 16 wherein at least one light distillate fraction is separated from the hydrogenated coal solution.
25. 26. The process of claim 25 wherein at least one distillate fraction heavier than said light fraction is subsequently separated from the hydrogenated coal solution, said heavier fraction containing heavy gas oil and dehydrogenated hydrocarbon solvent, and said heavy distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker recycle stock.
26. 27. The process of claim 26 wherein the catalytic cracker recycle stock is subjected to partial hydrogenation, and the partially hydrogenated catalytic cracker recycle stock thus prepared is used as a partially hydrogenated hydrocarbon solvent to solubilize and hydrogenate additional coal.
27. 28. The process of claim 16 wherein the hydrocarbon solvent contains a mixture of polycyclic hydrocarbons having about 2-4 condensed benzene rings before partial hydrogenation and at least one of said benzene rings is retained and 1-3 benzene rings are hydrogenated to produce naphthenic rings during partial hydrogenation, each part by weight of the coal is contacted for about 0.1-2 hours with about 0.2-20 parts by weight of the partially hydrogenated hydrocarbon solvent in the presence of elemental hydrogen and at a temperature of at least 650* F., the solvent density is at least 0.6 g./cc. and at least one light distiLlate fraction and at least one heavier distillate fraction are separated from the solution of hydrogenated coal, said heavier distillate fraction containing gas oil and dehydrogenated hydrocarbon solvent.
28. 29. The process of claim 28 wherein the partially hydrogenated hydrocarbon solvent is partially hydrogenated catalytic cracker slurry oil.
29. 30. The process of claim 29 wherein each part by weight of the coal is contacted with about 2-5 parts by weight of the partially hydrogenated catalytic cracker slurry oil, said heavier distillate fraction is catalytically cracked to produce lower boiling products and catalytic cracker slurry oil, and the catalytic cracker slurry oil thus produced is partially hydrogenated and used to solubilize and hydrogenate additional coal.

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