CA1232220A - Hydrogenation of undissolved coal and subsequent liquefaction of hydrogenated coal - Google Patents

Abstract

HYDROGENATION OF UNDISSOLVED COAL AND SUBSEQUENT
LIQUEFACTION OF HYDROGENATED COAL

ABSTRACT OF DISCLOSURE
A staged process for hydrogenation of undissolved coal and subsequent liquefaction of the hydrogenated coal to provide useful hydrocarbon liquid products including naphtha, gasoline and diesel fuels. These low boiling hydrocarbon liquids are produced by the process comprising:
(a) mixing solid coal particles with a hydrocarbon solvent oil in a solvent/coal ratio ranging from about 8/1 to about 1.5/1 to provide a flowable coal/oil slurry; (b) passing said coal/oil slurry and hydrogen upwardly through a first stage reaction zone containing a coal-derived liquid in a catalytic bed of particulate; catalyst maintained at a temperature ranging from about 400° to about 700°F and a hydrogen partial pressure of 100 to 2000 psig for a residence time sufficient to hydrogenate the solid coal particles; and (c) withdrawing the coal/oil slurry con-taining the hydrogenated coal particles from the first reaction zone and passing the coal/oil slurry to a second stage reaction zone containing a catalytic bed maintained at a temperature of between about 700° and about 850°F and a hydrogen partial pressure of 100 to 2000 psig to liquefy and convert the coal to useful hydrocarbon liquid fuel products. The first and second stage reaction zones may contain the same or different catalysts such as Co/Mo on a porous substrate such as alumina or silica. The process preferably uses a coal-derived slurrying oil and first stage temperature of 550-650°F. and second stage temperature of 800-825°F.

Description

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HYDROGENATION OF UNDISSOLVED COAL AND SUBSEQUENT
LIQUEFACTION OF HYDROGENATED COAL

BACKGROUND OF THE INVENTION

This invention relates to a coal liquefaction process, and more particularly, it relates to the hydra-genation of undissolved coal and subsequent liquefaction thereof to provide useful hydrocarbon liquid and gaseous fuel products, wherein solid coal particles are hydrogenated in a coal/oil slurry of a coal-derived solvent in the presence of a particulate hydrogenation catalyst.
Conventional processes for coal liquefaction and hydrogenation include a preheating or thermal dissolution step, for the coal-oil slurry feed prior to the catalyst reaction step as generally disclosed in US. Patent Nos.
3,519,555; 3,700,584; 3,791,957 and I 788~ Other coal hydrogenation processes use fine recycled catalysts at plug flow conditions and low solvent/coal ratios such as US. Patent Nos. 4,090,943 and 4,10~,775. In these processes, the coal-oil slurry is preheated to near the reactant temperature before feeding it into the catalytic reaction zone.
In these conventional coal hydrogenation processes which utilize the coal-slurry preheating step, the hydrogen donor potential or theoretical hydrogen concentration of the coal-derived slurring oil therein is limited by its mobility and the hydrogen is usually consumed during the coal preheating and dissolution steps. These processes are also lacking in that the coal is not sufficiently hydrogenated to fully liquefy or convert coal to useful hydrocarbon liquid and gaseous fuel products as provided herein..
The conventional methods of coal liquefaction attempt to liquefy coal while having donatable hydrogen .:~

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available in the liquid solvent to "seal off" free radicals which crack from the coal. Catalytic processes provide a greater quantity of hydrogen for this purpose by hydrogen-cling the solvent. In significant contrast, the process of the present invention relies on hydrogenation of the particulate coal in the first stage, but the predominant transfer of the donatable hydrogen to the coal particles taxes place before the liquefaction thereof Once the coal liquefies, the excess hydrogen in the products induces almost immediate reformation reactions which in turn result in stable, light hydrocarbon compounds. In conventional coal liquefaction processes, more heavy residual products are made since the polymerization reactions, i.e.; condemn-stations, are competitive with the hydrogen transfer from solvent reformation reactions which occur much slower.
In a process developed by Vader and described in Us Patent 4,331,530, a process for the hydrogenation of coal and subsequent treatment of hydrogenated coal to pro dupe fuels and chemicals is provided. In this process, there is not any solvent used and the hydrogen provided in the process involves the hydrogen transfer from the gas phase to solid phase. In an attempt to hydrogenate the coal, the coal has been pulverized into very fine particles.
This procedure of hydrogenating a dry coal provides great difficulty in the hydrogenation thereof in order to liquefy or convert such coal to useful fuel products. Thus, the present process is needed in order to fully and more come pletely convert the coal of various types to useful hydra-carbon liquids and fuel products, such as gasoline, diesel fuels and naphthaO

SUMMARY OF INVENTION

The present invention provides a staged process ~3~2~3 four the hydrogenation of coal and the subsequent liquefaction thereof to provide useful hydrocarbon liquid and gaseous fuel products. The process comprises:
pa) mixing solid coal particles with a hydrocarbon liquid solvent in a solvent/coal ratio ranging from about 8/1 to about 1.5/1 to provide a plowable coal/oil slurry of the solid coal particles;
(b) passing the coal/oil slurry and hydrogen upwardly through a first reaction zone containing a hydra-carbon liquid in a catalytic bed of particulate hydrogenation catalyst maintained at a temperature ranging from about 400 to about 700F and a hydrogen partial pressure of 100 to 2000 prig for a residence time sufficient to hydrogenate the solid coal particles in the coal/oil slurry;
(c) withdrawing the coal/oil slurry containing the hydrogenated coal particles from the first reaction zone and passing the coal/oil slurry to a second reaction zone which is maintained at a temperature between about 700 to about 850F, and a hydrogen partial pressure of 100 to 2000 prig for a residence time sufficient to convert the hydrogen, so coal particles to gas and liquid fractions;
Ed) passing said gas and liquid fractions from the second reaction zone to a gas-liquid-solid separation zone from which a hydrocarbon liquid stream containing a reduced solids concentration is recycled to provide a solvent liquid for the coal/oil slurry; and a purified hydrogen gas stream is recycled to provide the hydrogen partial pressure in the first reaction zoos, and a heavy liquid stream is removed contain-in an increased concentration of insoluble materials and ash; and (en recovering from the separation zone hydrocarbon liquid distillate and gaseous hydrocarbon products.

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- pa -On the process, the nominal residence time of the materials in the first reaction zone ranges from about 5 to about 90 minutes and the residence time in the second no-I.

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action zone ranges from about 1 to about 90 minutes.

BRIEF DESCRIPTION OF THE DRAWINGS
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This invention can be understood by reference tote accompanying drawings in which:
Fig. 1 is a schematic diagram of the present continuous two stage process for the hydrogenation/lique-faction of coal, wherein the hydrogenation reactor, pique-faction/conversion reactor, separation-purification systems and recycle conduits are shown.
Fig. 2 is a chart showing a comparison of yield distributions of solubles for the process of the present invention.
Fig. 3 is a graph showing the effect of hydrogen pressure on percent coal conversion.
Figs. 4 and 5 are charts showing the comparative conversion results for the present conversion process compared to other processes for bituminous and low rank coals.
Fig. 6 is a chart showing comparative performance of the present process compared to other known processes for sub-bitumlnous coal mixed with heavy petroleum resin solvent.

DESCRIPTION OF INVENTION
-The present process of hydrogenating coal particles and subsequently liquefying such to provide useful fuel products involves the operation of two close-coupled gala-lyric bed reactors, i.e., first and second stage reaction zones. In the first reaction zone, the conditions are designed to promote the hydrogenation of the coal and to effect most of the heteroatom removal to byproducts such I

as hydrogen sulfide, ammonia and waxer. In the second reaction zone, the conditions are maintained sufficient for the conversion liquefaction of the hydrogenated coal to convert it readily to hydrocarbon liquid products while removing still more of the heteroatoms, e.g., hydrogen sulfide, ammonia and water.
According to the present invention, coal is hydrogenated prior to liquefaction in a system capable of providing usable hydrogen to sites within the solid coal matrix. The process according to the present invention involves a well mixed catalytic first stage reaction zone in which a slurry of coal and hydrocarbon liquid solvent is present with any suitable hydrogenation catalyst under increased temperature and hydrogen pressure. A suitable catalyst would be a cobalt/molybdenum catalyst on a sub-striate of alumina. according to the present invention, there is no limitation as to the hydrogenation catalyst used in the process. That is, any catalyst may be used providing it will promote the hydrogenation of solid coal particles. also/ the catalysts would be either heterogeneous or homogeneous and can be supported on any porous substrate, e.g., alumina or silica or mixtures thereof. The catalysts used in the beds of the first and second stage reaction zones may be a particulate catalyst containing an active metal oxide selected from the group consisting of: Comma;
Nemo' H, Sun promoted Comma; W promoted Comma; Nix Cost Most Foes; Phase; Lit; and MgH2. Also, the catalyst used in the first and second reaction zones may be a noble metal such as platinum. More specifically, the catalysts may be a material having an active metal oxide selected from the group consisting of; metals of Group VIII of the Periodic Table, and their salts; tin; zinc; copper;
chromium; and antimony. The catalyst may be the same in both the first and second reaction zones but this is not -~23~

necessarily the preferred mode of operation.
The feed stock or the coal that is fed into this process and catalytically hydrogenated before it is pique-fled may be any bituminous coal, such as Illinois No. 6 or Kentucky No. 11, or a sub-bituminous coal such as Wyodak.
The feed material may also be lignite, or peat In each case, the type of feed stock used will dictate the conditions required in the first and second reaction zones.
In the process, hydrogen is provided initially to stat up the process but during the course of the continuous two stage operation, hydrogen is derived from the process and recycled to be fed into the first reaction zone to hydrogenate the feed stock, i.e., coal particles During the process, a sufficient amount of hydrogen is provided in order to fully hydrogenate the coal feed stock so that it may be liquefied or converted easily at the higher temperature within the second reaction zone. Under normal conditions, the amount of hydrogen consumed ox utilized in the first reaction zone, based on the weight of dry coal fed therein is between about 2.0 and about 4.0 W %. This amount ox hydrogen may vary as based on the type of coal feed that is utilized in the present process.
The coal-derived solvent used to make up the coal/
oil slurry may he any suitable coal-derived liquid material wherein a substantial portion thereof has a normal boiling point ranging from about 400F to about 1100F. Of this coal-derived liquid material (i.e., solvent?, at least about 50% has a normal boiling point above about 975F.
According to the present invention, it has been found that a suitable hydrocarbon liquid solvent utilized in the coal/oil slurry may be selected from the group consisting of petroleum-derived residual oil shale oil, tar sands bitumen, and an oil derived from coal other than that processed within the present process.

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The hydrocarbon solvent oil is catalytically hydrogenated in the first reaction zone and migrates into the pore structure of the solid coal particles where the solvent gives up hydrogen to the coal particle matrix. The solvent molecules do this repeatedly until an equilibrium hydrogen content is achieved in the coal particles and coal/
oil slurry.
In the first reaction zone, the coal is fed with hydrogen into the first reaction zone and through the catalytic bed, where the catalytic bed is maintained at a temperature ranging from about 400 to about 700F and a hydrogen partial pressure of 10~ to 2000 prig with the total pressure being between about Lund 4000 pug and preferably ranging between about 1000 and about 3000 swig The residence time of the coal in the first reaction zone ranges from about 5 to about 90 minutes, which is sufficient to hydrogenate the solid coal particles in the keelhaul slurry.
After the coal solid particles have been hydrogenated, the resulting keelhaul slurry is introduced into the second stage reaction zone where liquefaction of the undissolved coal particles occurs. The conditions in the second reaction zone are near to but less severe than the conditions for the conventional liquefaction of coal. Since the coal structures are weakened by the hydrogenation of the matrix, less thermal energy will be required to liquefy the coal in the second reaction zone since an excess of hydrogen exists in the solid phase of the coal as well, a lower hydrogen partial pressure will still provide sufficient gas phase hydrogen to terminate free radicals of liquefaction products. The end result is to produce lighter products (i.e., primary products, distillate oil and naphtha) with less severe reaction conditions relative to the conventional I

coal liquefaction process. The temperature of the second reaction zone ranges from about 700 to about 850~F and the hydrogen partial pressure ranges from about 100 to about 2000 prig with the total pressure being between about 500 and about 4000 prig and preferably ranging between about 1500 and about 2500 prig. The residence time of the mat-trials in the second reaction zone ranges from about 1 to about 90 minutes.
The catalytic bed in the first reaction zone can be a fluidized bed or an ebullated bed, with an ebllllated bed being preferred. Although the second reaction zone is preferably a catalytic reaction zone, it may instead be a non-catalytic back mixed thermal reaction zone.
The coal particles fed to the present process have a particle size ranging from less than 20 mesh to greater than 400 mesh (US. Sieve Series?, and preferably from less than 70 mesh to greater than 100 mesh USE.
Sieve Series).
The products of the two stage hydrogenation and conversion process generally are distillate liquid hydrocarbon products such as naphtha, gasoline and diesel fuel, and insoluble materials and ash are removed from the process.
According to the present invention the product yields as provided by the prehydrogenation of the coal before it is liquefied results in the advantages of:
(a) the need or less severe conditions in the conversion/liquefaction reaction zones; and (b) an increase in the yield or production of the light liquid products, i.e., hydrocarbon liquid distillate hydrocarbon products.
According to the present invention and as indicated and discussed below in the Examples, by use of the present ~Z3~

g invention, an increase in product yields will average from between at least about 5 and about 24~ over that resulting from a conventional coal liquefaction process or single stage process The yields from the present process of hydrocarbon liquid material such as cyclohexane solubles ranges from about 60 to abut 90 W % of the coal feed.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to Figure 1 of the drawings, a continuous two-stage coal liquefaction process is schematically shown As shown, a coal feed or feed stock is provided at 10. The coal being e.g. an Illinois No. 6 coal or other bituminous coal, is ground to a particle size of about 70 mesh (US.
Sieve Series) and smaller and dried to remove surface moisture and passed to a slurry mix tank 12. Here the particulate coal is blended with a process derived oil or an oil derived from coal in other than the process herein.
The process derived oil or solvent is blended in a weight ratio of solvent to coal which is at least sufficient to provide a pump able slurry mixture, and usually has a weight ratio range of solvent to coal ranging from about 8/1 to about 1.5/1.
The coal/oil slurry, i.e., blend from slurry mixing tank 12, is pressurized by pump I heated in feed preheater 26 and pumped through conduit 15 to blend along with make-up hydrogen through conduit 17 directly to an ebullated bed reactor 20 containing hydrogenated coal-derived liquid, the hydrogen and a bed 22 of particulate hydrogenation catalyst. The coal/oil slurry is passed with hydrogen through flow distributor plate 21 and upwardly through the catalyst bed 22 at sufficient velocity to expand the bed. The catalyst 22 which suitably may come prose particles such as 0~030 0.130 inch diameter extradites ye .

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ox nickel/molybdate or cobalt/molybdate on alumina or a similar material, is expanded by at least about 20~ and not over about 100% of its settled height by the up flowing fluids, and is wept in constant random motion during reaction by the upward velocity of the coal/oil slurry and hydrogen gas.
The oilily slurry is passed upwardly through reactor 20 and in contact with the catalyst at average nominal residence times ranging from about 5.0 to about 90 minutes, and preferably from about 10 to about 30 minutes The reaction conditions maintained within the first reaction zone 20 are a temperature of from 400 to 700F, preferably from about 550F to about 650F, and a 100-2000 prig hydrogen partial pressure or a total pressure of between about 100 and 4000 prig, preferably ranging from about 1000 to about 3000 prig. The reactor liquid is recycled through a down comer conduit 24 and recycle pump 25 and then passed upwardly through the distributor plate 21 to maintain sufficient upward liquid velocity to expand the catalyst bed 22 and maintain the catalyst at random motion in the liquid to assure intimate contact with complete reactions to substantially hydrogenate the coal particles.
From the first stage reactor 20 through effluent stream 29, the hydrogenated coal particles in the coal/oil slurry are passed into the bottom of the second stage reactor 30. The hydrogenated coal is then passed through a flow distributor and catalyst support plate 31 into an ebullated bed 32 of catalyst, in much the same way as the material flows through first stage reactor 20. The hydrogenated coal/oil slurry is passed upwardly through the reactor 30 in contact with the catalyst at nominal average residence times ox about 1.0 to about 90 minutes, ~3~2~

and preferably from about 10 to about 30 minutes. The reaction conditions maintained in the second stage no-actor 30 are a temperature ranging from about 700 tug about 850F, preferably about 800F to 825F, and 100~2000 prig hydrogen partial pressure or a total pressure of between about 500 and about 4000 prig, preferably ranging from about 1500 to about 2500 prig. The reactor liquid in the second reactor 30 is recycled through down comer conduit 34 and recycle pump 35 to heat exchanger 36 for heating and controlling the temperature of the reaction liquid of the second reactor 30 within a relatively narrow range.
The reactor liquid is then passed upwardly through distributor plate 31 to maintain sufficient mixing and upward liquid velocity to expand the catalyst bed and maintain the catalyst in random motion in the liquid to assure intimate contact and complete reactions.
From the second reactor 30 through effluent stream 39, the reaction liquid, i.e., liquefied coal, is usually cooled and passed to hot separator 40. The resulting vapors are passed through conduit 41 and may be processed in a first separation-puri~ication system 60 as desired to obtain recovered low purity hydrogen, which is recycled through conduit 16 to preheater 18 and then into the bottom of reactor 20. Other light gases such as hydrogen sulfide, NH3, and Cx are emitted from separation-purification system 60 through conduit 51; and product gases, i.e., low boiling, light hydrocarbon gases are emitted from system 60 through conduit 52.
From the bottom of the hot phase separator 40, a coal-derived slurry liquid is passed through conduit 42. The slurry liquid in conduit 42 is processed in a second separation-purification system 62 to obtain a no-cycle liquid or slurry containing a reduced solids con-

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cent ration which is passed through conduit 44 to the slurry mix tank 12~ The coal-derived liquid solvent recycled through conduit 44 has a normal boiling point ranging from about 400F to about 1100F., with at least about 50 W of the solvent material having a normal boiling point above about 975F. Also, the slurry liquid from conduit 42 is processed in the second system 62 as desired to remove ash and insoluble materials through conduit 45, and to remove product liquids, i.e., distillate hydrocarbon liquids, through conduit 46.
The recovered hydrogen is recycled into the process through conduit line 16 to preheater 18, where it is heated prior to being passed through conduit 19 into the bottom of the first reactor 20. This arrangement provides the hydrogen needed in the continuous process of the present invention.
The present invention and its advantages are further illustrated by the following examples, which are not intended to be limiting for the scope of the invention.

Present and.~Sirlgle Stage Coal Liquefaction Processes In order to show the effectiveness of the present process, a comparison was made between the present process and a single stage "Cole" coal liquefaction process.
The conditions and process yield results of the two pro-cusses are provided below in Table 1. In both cases, Illinois No. coal from Burning Star mine and known to be relatively difficult to liquefy, was processed and liquefied.

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Comparison of Continuous Process Results For Burning Star Illinois No. 6 Coal Present "H-Coal'i Reaction Conditions Process Process sty stage temperature, F5S0 sty stage reaction time, mint 30 sty stage Ho pressure, prig 2000 end stage temperature, F800 850 end stage reaction time, min. 30 30 end stage Ho pressure, prig 2000 2250 Yields, W % Dry Coal -Cluck Gas 7.2 9.9 C4-400F Liquid 15.4 19.8 400-650F Liquid 19.8 18.6 650-975F Liquid 21.1 10.0 975F~ Material 11.8 19~5 Total C4-97$F Liquid 56.3 48.4 Hydrogen Consumption 4.6 5.2 Kiwi Conversion 93,0* 94.0 HO, ISSUE, NH3, eta, 13.0 9.9 Ash 11.8 11.5 *Not Optimized.

As shown in Table l above, the present process yields less hydrocarbon gas, more distillate liquid, less 975F~ bottoms fraction moreheteroatom gases, and consumes less hydrogen than in the single stage "H-Coal" process.
These results, as shown in Table 1, were obtained at a lower maximum temperature and hydrogen partial pressure for the present process than those employed in the con-ventional Coal process.

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The results listed in Tables 1, 2 and 3 are for approximately the same catalyst ago Table 2, below, shows a further comparison between the present process and a single stage "Cole" process operated at the conditions listed in Table 1. These results show that there is less heteroatom sulfur and nitrogen compounds in the products, ire., product fractions from the present process than in the products from the conventional single stage "H-Coal"
process. The advantages of the present process over the single stage "H Coal" process, which were operated at the conditions listed above in Table 1, are shown below in Table 3. The higher C4-975F fraction distillate yields and lower hydrogen consumption result in a much higher hydrogen efficiency for the present process as compared to the single stage "H-Coal" process.
Table 2 Comparative Heteroatom Removal For Single Slave us Two Stave CatalYtic-catalytic Process "H-Coal" Present Process_ Process Sulfur in Products. W
C4-400F 0.04 0.05 400-650F OWE 0.03 650~975F 0.18 0.05 Nitrogen in Products, W.%

400-650F OWE 0.19 650-975F OWE Owe ~322~

Process Efficiency Comparison .

"H-Coal" Present Process Process C4-975F Yields, As W of Dry Coal 47 56 Hydrogen Efficiency Expressed as Ratio of C4-975F
Yield/
Total Hydrogen Consumed OWE 12.2 Present and Two Stage Thermal/
Catalytic Liquefaction Processes .. . . _ In order to further illustrate the effectiveness of the present process, a comparison was made between the present process and a two stage thermal/catalytic coal liquefaction process. The operating parameters and yields for the present process and the thermal/catalytic two stage process are provided below in Table 4. In both cases, Burning Star, Illinois No 6 coal was processed and liquefied. The results of Table 4 are for a comparable catalytic age.

Comparison of Continuous Process Results For Burning Star Illinois No. 6 Coal ._ - Thermal/
: Present Catalytic Reaction Conditions:ProcessTwo~Stage sty stage temperature, OF 550 850 sty stage reaction time, min. 30 30 sty stage Ho pressure, prig. 2000 2250 Jo :~23~

Thermal/
Present Catalytic Reaction Conditions: Process Two-Stage end stage temperature, OF 800 770 end stage reaction time, min. 30 30 end stage Ho pressure, prig 2000 2250 Yields, W % Dry Coal Cluck Gas 7.2 7.2 C4-400F Liquid 15~2 17.4 400-975F Liquid 40.9 34.0 975F+ Material 11.~8 15~8 Total C4-975F Liquid 56.3 51.4 Hydrogen Consumption 4.6 5.1 Coal Conversion 93.0* 94.0 HO, HIS, NH3, etc. 13~0 12.8 Ash 11.8 11.7 *Not Optimized As shown in Table 4, equivalent gas yields and light distillates C4-400F fraction yields are obtained, but more diesel and heavy distillate vacuum gas/oil fractions are obtained from the present process than from the thermal/
catalytic process. In addition, total distillate yields are increased and total 975F~ bottoms yields are decreased for the present process as compared to the thermaltcatalytic process.
A comparison of the heteroatom contents for the various product cuts from the thermaltcatalytic and present process are listed below in Table JO These results show that the present process produces less heteroatom sulfur and nitrogen compounds in the various product cuts or fractions. The process efficiencies for coal liquefaction aye and hydrogen consumption for the two processes are listed below in Table 6. These results show that higher distillate yields and lower hydrogen consumption results in better process conversion and hydrogen efficiency for the present process than for the thermal/catalytic process, Comparative Heteroatom Removal . For .
Two Stage Processes Thermal/
Catalytic Present . ......... Two Stage Process Sulfur in Product Fractions W%
C4-400F 0.16 0.05 400~650F 0.10 0.03 650-975F 0.16 0.05 Nitrogen in Product Fractions, W%
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C4-400F 0.07 0.09 400-650F 0.25 Oily 650-975F O o 64 O o 60 Tub 6 Process Efficiency Comparison Thermal/
Catalytic Present . Two Stage Process C4-975F Yield, so W% of dry coal 52 56 Hydrogen Efficiency Expressed as Ratio of C4-975F/
total hydrogen consumed 10~6 12.2 :~;23~

Comparison of Present Process With Existing Coal Liquefaction Processes In order to show the effectiveness of the present process, a comparison was made of a run of the present process for the liquefaction of coal with runs of existing coal liquefaction processes: "H-Coal" J Chevron Coal Pique-faction (CCLP); Solvent Refined Coal I (SAC I); and SAC Rio In all cases, Burning Star, Illinois No. 6 coal was processed and liquefied. The operating conditions for the various runs were similar and comparable to those for the present and Coal processes, listed above in Table I of Example I The results and yields for the various processes are provided below in Tubule.

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Yield of Burning Star Illinois No 6 Coal (All quantities expressed in White MA coal) Present Fraction Process "H-Coal" CCLP* SAC I** SAC II**
NH3, HIS, HO, 12 11 15 10 12 CO, COY
C1-C3 Gases 8 11 7 7 17 C4-400F Lockwood 23 9 NO 11 975F+ Material 10 21 9 63 26 Unconverted Coal 6 6 10 8 4 Ho Consumption 5 5 5 3 3 Total 105 105 105 103 103 -NO - not available *Data is extracted from TOGA results published by Chevron;
Rosenthal JAW., et at, "The Chevron Coal Liquefaction Process" EPRI Contractors' Conference, Thea midyear Mug.
May 10-13, 1982.
**Data from: Elliot Mud Chen~stry of Coal Utilization, end supplementary Vol. 1981, John Wiley & Sons, Inc. NY, NY.
(NOTE: Thermogravimetric Analysis may tend to shift disk tillation results from high boiling point to Lowe ~3Z~

As shown above, in Table 7, the present process gives higher distillate yields of C4-975F fraction than any reported process Less 975F+ bottoms yield and higher hydrogen efficiency are also observed for the present process. Also, the results for the present process were obtained at lower hydrogen partial pressures than those employed in the single stage "H-Coal" process.

Present and "H-Coal" Batch Processes ... , .. _ _ . .... . . .

In order to further illustrate the overall effect-iveness of the present process, batch process runs of the present and the single stave Coal processes were made.
The conditions and yields of both process runs are provided below in Table 8, Also, in Figure 2, the effectiveness of the present process is demonstrated for the conversion of Burning Star Illinois No. 6 coal as compared to that of the single-stage "H-Coal" process. The processes in both runs A and B use a standard Comma catalyst, whereas in run C a different Coo catalyst, i.e., AMOCAT* lo is used. The results, it yield distributions, are set forth as con-version to solubles in various solvents such as cyclohexane, Tulane, and tetrahydrofuran.
The results provided in Figure 2 show that for a given thermal severity in the end stage reaction, the present process yields higher conversions to various solubles than does the conventional "H-Coal" process at the same severity. on increase of about 20% in cyclohexane solubilities is obtained. Increases in Tulane solubilities range from about 15 to about 20% and increase in tetrahydro-Furman solubles (a measure of total conversion) range about * Trademark I

5 to 10%. Table 8 lists the maximum yields obtained from Illinois No. 6 Burning Star Coal in the batch tests made at substantially the same reaction conditions. These results show the superiority of the present process over the "H-Coal"
process. The total conversions of coal for tetrahydrofuran solubles is 6% higher for the present process, for cycle-hexane solubles is 23% higher for the present process, and maximum obtained Tulane solubles are 20~ higher for the present process than for the Cole" process. The higher total percent conversion of coal for the present process, as shown in Figure 2 are: (l) 6% higher for tetrahydrofuran solubles; (2) 23% higher for cyclohexane solubles; and (3) 20% higher for Tulane solubles than for the single stage "H-Coal" process.

Maximum Comparative Yields for Illinois No. 6 Coal in Batch Test Yields, We MA Colloquial" Process Present Process , _ .. . .
Cyclohexane Solubles 67 90 Tulane Solubles 73 93 Tetrahydrofuran Solubles 90 96 Reaction Conditions sty Stage Temperature, OF -- 550 sty Stage Time, miss. -- 60 sty Stage Ho Pressure, prig -- 2000 end Stage Temperature, F830 800 end Stage Time/ miss. 30 60 end Stage Ho Pressure, prig 2000 2000 In Figure 3, the effect of hydrogen pressure on the present process is illustrated. Batch runs were made .. Jo I

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on Illinois No. 6 coal using cobalt/molybdenum catalyst at hydrogen partial pressures of 500, 1000 and 2000 prig. As shown, the yields of solubles at 500 prig pressure in the present two-stage process conducted at 550DF in the first stage for a 30 minute residence time, and at 800F and 30 minutes residence time in the second stage, are greater than those obtained for the single stage "H-Coal" process-in at 500 prig hydrogen pressure, 800F temperature, and 60 minutes residence time. Thus, it follows that the present process can be operated at lower pressures than the convent-tonal single-stage Coal process and still obtain higher yields of desired hydrocarbon liquids.

Present and H-Coal Processes In Conversion of Various Coals In order to show the electiveness ox the present process for processing different coals, runs were made using the present process and the conventional single stage H-Coal process for both Burning Star, Illinois No. 6 coal and a lo volatile coal. The operating conditions for both the present and H-Coal processes were the same as those listed above in Table I of Example I. The results of these tests are illustrated in Figure 4, and are presented on a conversion to various solubles bases, i.e. to cyclohexane solubles, to Tulane solubles and to tetrahydrofuran solubles.
The cross-hatched bars represent equivalent second stage thermal seventies for the various tests. The open bars represent the maximum obtained conversion for the individual processes.
In Figure Noah maximum conversion data is illustrated .
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for the low volatile coal since these results represent a single data point. The data in Figure 4 indicates that the low volatile coal is less reactive under the conventional H-Coal process than Illinois No. 6 Burning Star coal. On the other hand, the results for the present process show that the low volatile coal is as reactive as the Illinois No. 6 coal, and yields far more solubles than the con-ventional H-Coal process yields with this coal. Thus, in the present process, an unreactive low volatile bit-urinous coal is made as reactive highly reactive Burning Star, Illinois No. 6 coal.

Present, "H-Coal" , and Thermal/
Catalytic Processes .

A series ox runs were made to show the effective-news of the present process ion the conversion of a high rank, medium volatile bituminous, high ash coal. The present process was compared to a conventional single stage Coal process and to a two-stage thermal catalytic process in small batch runs for raw and cleaned coals. The operating conditions or the different processes were as follows:

Conditions Processes Thermal "H-Coal" Catalytic Present sty Stage Temperature, OF 550 550 sty Stage Reaction Time, Min. 30 30 sty Stage Ho Pressure, prig 2000 2000 end Stage Temperature, OF 850 850 800 end Stage Reaction Time, Mooney 30 30 end Stage Ho Pressure, swig 2250 2000 ~Z3Z~2~

The results of the various runs are illustrated and set forth in Figure 5. The illustrated results of Figure 5, show that on an ash free basis, the present process yields higher conversions to cyclohexane, Tulane and tetrahydrof~ran (THIEF solubles than does the "H-Coal"
process or the thermal/catalytic process. For this coal a 17% increase in cyclohexane solubles, a 12~ increase in Tulane solubles and a 1 to I increase in the THY solubles, are observed for the present process over the Coal process. Thus, the present process is effective in converting a high rank, medium volatile bituminous coal to solubles and hydrocarbon liquid products.

Present; One Stage Thermal, "H-Coal" ;
Thermal/Thermal; and Thermal/Catalytic Processes A series of runs were made to show the effective-news of the present process in the conversion of a highly unreactive, Western Canadian sub-bituminous coal. The series of runs compared the effectiveness of the present process with (1) one-stage thermal, I "H-Coal" , (3) two-stage thermal/thermal and I) two-stage thermal/catalytic processes. In comparing these processes small batch tests .
were conducted, employing a heavy petroleum resin as a solvent for the coal.
The operating conditions for the different pro-cusses were as follows:

~Z3~

Conditions Processes _ thermal Thermal/
Thermal "H-Coal" Thermal Cata1~tic Present sty Stage Twitter, OF 550 550 550 sty Stage reaction Time, Min. 30 30 30 sty Stage Ho Pressure prig 2000 2000 2000 end Stage Temperature F850 850 800 800 800 end Stage Reaction Time, Min. 30 30 30 30 30 end Stage Ho Pressure, prig 2000 2250 2000 2000 2000 The results of the comparative tests as illustrated in Figure 6, are based on a total slurry solubles of a MAFIA. basis. The results of the present process run show an increase of slurry solubles of 11~ cyclohexane sol-rubles, 11~ Tulane solubles and 11% tetrahydrofuran solubles over those produced by the "H-Coal" process. Also, the results show that for the present process, 100% tetrahydrofuran volubility is obtained. This indicates that all the coal is convertible to tetrahydrofuran solubles in the present process, hut is not convertible in any other test mode shown. Also a higher conversion to cyclohexane and Tulane solubles were obtained for the present process than for any other process mode.

Claims (39)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.

1. A.continuous two reactor stage coal conversion process for hydrogenation of coal and subsequent liquefaction thereof for producing hydrocarbon liquid and gas products, comprising:
(a) mixing solid coal particles with a hydrocarbon liquid solvent in a solvent/coal ratio ranging from about 8/1 to about 1.5/1 to provide a flowable coal/oil slurry feed of said solid coal particles;
(b) passing said coal/oil slurry and hydrogen upwardly through a first reaction zone containing a coal-derived liquid and a catalytic bed of particulate catalyst maintained at a temperature ranging from about 400° to about 700°F, and a hydrogen partial pressure of 100 to 2000 psig for a residence time sufficient to hydrogenate said solid coal particles in said coal/oil slurry;
(c) withdrawing said coal/oil slurry containing said hydrogenated coal particles from said first reaction zone and passing said coal/oil slurry to a second reaction zone which is maintained at a temperature of between about 700° and about 850°F, and a hydro-gen partial pressure of 100 to 2000 psig for a residence time sufficient to convert said hydro-genated coal particles to gas and liquid fractions;
(d) passing said gas and liquid fractions from said second reaction zone to a gas-liquid-solid separa-tion zone, from which a hydrocarbon liquid stream containing a reduced solids concentration is recycled to provide the solvent liquid for said coal/oil slurry, and a purified hydrogen gas stream is recycled to provide the hydrogen partial pressure in the first reaction zone, and a heavy liquid stream is removed containing an increased concentration of insoluble materials and ash; and (e) recovering from said separation zone hydrocarbon liquid distillate and gaseous hydrocarbon products.

2. A process according to claim 1, wherein the bed in the first reaction zone is an ebullated catalytic bed comprising a solid porous catalyst selected from the group consisting of Co/Mo; Ni/Mo; Li, Sn promoted Co/Mo; W pro-moted Co/Mo, NiS; CoS; MoS; FeS, FeS2; LiH, and.MgH2.

3. A process according to claim 1, wherein the second reaction zone contains an ebullated catalytic bed comprising a solid porous catalyst selected from the group consisting of: Co/Mo; Ni/Mo; Li, Sn promoted Co/Mo, W promoted Co/Mo;
NiS; CoS; MoS; FeS; FeS2; LiH, and MgH2.

4. A process according to claim 2 or claim 3, wherein the catalyst is supported on a porous substrate.

5. A process according to claim 2 or claim 3, wherein the catalyst is supported on a non-porous substrate.

6. A process according to claim 2 or claim 3, wherein the catalyst is supported on a porous substrate of silica, carbon or alumina or mixtures thereof.

7. A process according to claim 2 or claim 3, wherein the catalyst is supported on a non-porous substrate of aluminum oxide pellets, clays or crystals.

8. A process according to claim 1, wherein the second reaction zone is a non-catalytic backmixed thermal reaction zone.

9. A process according to claim 1, wherein the catalytic bed of the first reaction zone is a pulsed bed, a fluidized bed, or an ebulllated bed.

10. A process according to claim 1, wherein the second reaction zone contains a catalytic bed which is a fixed bed, pulsed bed, fluidized bed, or an ebullated catalyst bed.

11. A process according to claim 1, wherein a substantial portion of said coal-derived liquid solvent material has a boiling point ranging from about 400°F to about 1100°F.

12. A process according to claim 1, wherein at least about 50% of said coal-derived liquid solvent material has a boiling point above about 975°F.

13. A process according to claim 1, wherein the amount of hydrogen utilized in the first reaction zone ranges from about 2.0 to about 4.0 W % of the dry coal feed.

14. A process according to claim 1, wherein the hydro-carbon liquid distillate products include naphtha, gasoline, and diesel fuel.

15. A process according to claim 1, wherein the temp-erature of the first reaction zone is about 550°F-650°F and the residence time of the material therein ranges from about 5 to about 90 minutes, and the temperature of the second reaction zone is about 800°F-825°F and the residence time therein ranges from about 1 to about 90 minutes.

16. A process according to claim 1, wherein the residence time of the material in both the first and second reaction zones ranges from about 10 to about 30 minutes.

17. A process according to claim 1, wherein the hydro-carbon solvent utilized in the coal/oil slurry is selected from the group consisting of petroleum-derived residual oil, shale oil, tar sands bitumen, and an oil derived from coal other than that processed herein.

18. A process according to claim 1, wherein the total pressure maintained in said first reaction zone ranges from about 100 to about 4000 psig.

19. A process according to claim 1, wherein the total pressure maintained in said second reaction zone ranges from about 500 to about 4000 psig.

20. A process according to claim 1, wherein the coal of said coal/oil slurry feed is selected from the group consisting of bituminous and subbituminous coals, lignite, and peat.

21. A process according to claim 1, wherein the catalyst of the catalytic bed of the first reaction zone is a material selected from the group consisting of: metals of Group VIII
of the Periodic Table and their salts; tin; zinc; copper;
chromium; and antimony.

22. A process according to claim 1, wherein the second reaction zone contains a catalytic bed comprising a material selected from the group consisting of: metals of Group VIII
of the Periodic Table and their salts; tin; zinc; copper;
chromium; and antimony.

23. A process according to claim 21 or claim 22, wherein the catalyst is supported on a porous substrate.

24. A process according to claim 21 or claim 22, wherein the catalyst is supported on a non-porous substrate.

25. A process according to claim 21 or claim 22, wherein the catalyst is supported on a porous substrate of silica, alumina or carbon or mixtures thereof.

26. A process according to claim 21 or claim 22, wherein the catalyst is supported on a non-porous substrate of aluminum oxide pellets, clays or crystals.

27. A process according to claim 1, wherein said coal particles have a particle size ranging from less than 20 mesh to greater than 400 mesh (U.S. Sieve Series).

28. A process according to claim 1, wherein said coal particles have a particle size ranging from less than 70 mesh to greater than 100 mesh (U.S. Sieve Series).

29. A continuous two stage coal conversion process for hydrogenation of coal and subsequent liquefaction thereof for producing hydrocarbon liquid and gas products, comprising:
(a) mixing solid coal particles with a coal derived hydrocarbon liquid solvent in a solvent/coal ratio ranging from about 8/1 to about 1.5/1 to provide a flowable coal/oil slurry feed of said solid coal particles;
(b) passing said coal/oil slurry and hydrogen upwardly through a first reaction zone containing a catalytic bed or particulate hydrogenation catalyst maintained at a temperature ranging from about 400° to about 700°F, and a hydrogen partial pressure of 100 to 2000 psig for a residence time sufficient to hydro-genate the solid coal particles in said coal/oil slurry;
(c) withdrawing said coal/oil slurry containing said hydrogenated coal particles from said first reaction zone and passing said coal/oil slurry to a second reaction zone containing a catalytic bed which is maintained at a temperature of between about 700°
and about 850°F, and a hydrogen partial pressure of 100 to 2000 psig and a residence time sufficient to convert said hydrogenated coal particles to gas and liquid fractions;
(d) passing said gas and liquid fractions from said second reaction zone to a gas-liquid-solid separa-tion zone from which a hydrocarbon liquid stream containing a reduced solids concentration is re-cycled to said coal mixing step to provide a coal-derived liquid for said coal/oil slurry, and a purified hydrogen gas stream is recycled to said first reaction zone to provide the hydrogen partial pressure in the first reaction zone, and a heavy liquid stream is removed containing an increased concentration of insoluble materials and ash; and (e) recovering from said separation zone hydrocarbon liquid distillate and gaseous hydrocarbon products.

30. A coal conversion process according to claim 29, wherein said catalytic bed of the first reaction zone is a pulsed bed, a fluidized bed, or an ebullated bed.

31. A process according to claim 29, wherein said second reaction zone contains a catalytic bed which is a fixed bed, pulsed bed, fluidized bed, or an ebullated type bed.

32. A coal conversion process according to claim 29, wherein said catalyst bed in the first reaction zone is an ebullated catalytic bed containing a solid particulate catalyst comprising a metal selected from the group con-sisting of: Co/Mo, Ni/Mo; Li, Sn promoted Co/Mo; W promoted Co/Mo; NiS; CoS; MoS; FeS; FeS2; LiH, and MgH2 and supported on a suitable substrate material.

33. A coal conversion process according to claim 29, wherein said catalytic bed in the second reaction zone is an ebullated catalytic bed containing a solid particulate catalyst comprising a metal selected from the group consisting of: Co/Mo; Ni/Mo; Li, Sn promoted Co/Mo, W promoted Co/Mo;
NiS; MoS; FeS; FeS2; LiH, and MgH2 and supported on a suitable substrate material.

34. process according to claim 32 or claim 33, wherein the catalyst is supported on a porous substrate of silica, carbon or alumina.

35. coal conversion process according to claim 29, wherein the amount of hydrogen utilized in the first reaction zone ranges from about 2.0 to about 4.0 W % of the coal feed.

36. A coal conversion process according to claim 29, wherein said coal feed is selected from the group consisting of bituminous and subbituminous coals, lignite, and peat.

37. A process according to claim 29, wherein said coal particles have a particle size ranging from less than 20 mesh to greater than 400 mesh (U.S. Sieve Series).

38. A coal conversion process according to claim 29, wherein the residence time of the material in the first reaction zone ranges from about 5 to about 90 minutes, so as to achieve an equilibrium hydrogen content in the coal particle matrix, and the residence time in the second re-action zone ranges from about 1 to about 90 minutes to liquefy the hydrogenated coal particles.

39. A coal conversion process according to claim 29, wherein the hydrocarbon liquid distillate products include naphtha, gasoline, and diesel fuel.