Batch Autoclave Studies of Catalytic Hydrodesulfurization of Coal Y. K. Yen, D. E. Furlani, and S. W. Weller’ Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 142 74
The liquefaction and hydrodesulfurizationof a high sulfur Kentucky coal has been studied in batch autoclave experiments, with tetralin or methylnaphthalene as solvents, and several Co-Mo-A1203 catalysts. In tetralin, an excellent hydrogen-donor solvent, gas phase hydrogen and catalyst are still important in determining both the conversion of asphaltene to oil and the extent of desulfurization. Superimposed on other effects, the disproportionation of tetralin to naphthalene and decalin has been discovered to occur to approximately equilibrium at 455 OC, even in nitrogen and with no catalyst. Two commercial catalysts and two catalysts made from controlled-pore size aluminas have been studied in coal hydrodesulfurizationwith methylnaphthaleneas solvent, at a 1 % catalyst level. Appreciable differences were observed in product distribution. The most favorable results were obtained with large pore diameter (220 A) catalyst, even though this had the lowest total surface area.
Catalysis in coal hydrogenation was extensively studied several decades ago (Pelipetz et al., 1948; Weller et al., 1949; Weller et al., 195Oa,b; Pelipetz et al., 1950; Clark et al., 1950; Weller and Pelipetz, 1951 (a); Weller et al., 1951a; Weller and Pelipetz, 195lc). In that work attention was focussed largely on catalyst screening and the effects of catalyst distribution in the absence of a solvent. However, those studies did lead to proposals o f (a) a kinetic scheme in which the conversion of coal to asphaltene (benzene-soluble, pentane-insoluble product) proceeds much more rapidly than the subsequent conversion of asphaltene to oil (pentane-soluble product), and (b) a reaction mechanism which provided for the rapid, thermal or acid-catalyzed production of reactive fragments which are either stabilized by catalytic hydrogenation to give liquid products, or alternatively react with each other to yield a refractory “coke.” Very little attention was paid a t that time to the question of hydrodesulfurization. Some subsequent Bureau of Mines studies of catalysts for coal hydrogenation have been summarized in two review bulletins (Hawk and Hiteshue, 1965; Wu and Storch, 1968). Donath (1963) has given an excellent overview of catalytic coal hydrogenation, both historically and as the situation appeared about a decade ago. The noncatalytic pressure extraction (solvation, dissolution) of coal has been extensively studied since the early work of Pott and Broche (Pott et al., 1933) with a tetralinphenol-naphthalene solvent. The usefulness of a high boiling point, a hydroaromatic structure (e.g., tetralin), and polarity (e.g.. a phenolic hydroxyl or an amine) in the solvent has been shown by the work of Orchin and Storch (1948), Dryden (1950, 1963), and Oele et al. (1951), among others. Particularly elegant work on the comparative kinetics of coal pyrolysis, dissolution, and hydrogenation has been published by Hill, Wiser and co-workers (Wiser, 1968; Wiser et al., 1971). It has been generally accepted that a hydroaromatic solvent donates hydrogen to coal during the extraction process, with resultant mild hydrogenolysis (Orchin and Storch). The possibility that a disproportionation naphthalene decalin, might reaction, such as tetralin
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Ind. Eng. Chem., Prod. Res. Dev., Vol. 15, No. 1, 1976
be occurring in this system seems not to have been examined. In the past several years processes have been announcedfirst by the Bureau of Mines and subsequently by a few private corporations-for the catalytic hydrodesulfurization of a coal-recycle oil slurry by passage through a fixed bed of catalyst (Akhtar et al., 1971, 1972; Yavorsky et al., 1972). The Bureau of Mines’ process (“Synthoil”) utilizes pelleted cobalt molybdate-alumina as catalyst. The results of batch autoclave screening tests of a wide variety of catalysts were recently presented (Kawa et al., 1974). These screening tests, conducted with a charge of 50 g of coal, 75 g of tar, and 50 g of catalyst, indicated that of the catalysts examined, the most effective for both desulfurization and oil production was a commercial, silica-promoted Co-MoA1203 (Harshaw 0402T). This catalyst has been extensively used in the pilot plant work conducted a t the Bureau of Mines. The present paper contains the first results of a program of batch autoclave studies to examine some of the catalyst and solvent variables associated with the hydrodesulfurization of coal with Co-Mo-AleOa catalysts. The results presented here include (a) product distribution and analysis during hydrodesulfurization runs with tetralin as solvent, as a function of temperature, gas, and catalyst concentration; (b) analyses for naphthalene, tetralin, and decalin in the tetralin and benzene distillation cuts from these runs; and (c) studies of pore size and particle sizes effects with Co-Mo-A1203 made from Corning controlled-pore aluminas, along with comparison with two commercial catalysts, in methylnaphthalene as solvent. In all cases a high sulfur, high ash Kentucky coal was used. Experimental Section Equipment. All autoclave experiments were conducted in a 1-1. stirred autoclave (Autoclave Engineers, Model MB-1005 MagneDash). The autoclave was provided with a thermowell; a gas inlet port, connected (with valving) to a hydrogen cylinder or to a nitrogen cylinder, and to a pressure gauge; a port for connection to a rupture disk assem-
bly; and a port for gas discharge. The vertical magnetic rod of the MagneDash was provided with two disks or “dashers,” of which the upper dasher broke the gas-liquid interface during its travels, and the lower one stirred the solvent, coal, and catalyst particles. Modelling experiments outside the autoclave indicated that a “dasher” amplitude of 2.1 cm and frequency of 180-240 strokes per minute gave good mixing in this multiphase system. A glass liner, which just fitted into the autoclave, was used to eliminate any catalyst “memory” effects by the autoclave walls. The autoclave temperature was measured by an iron-constantan thermocouple inserted into the thermowell. A Perkin-Elmer 154D vapor fractometer was used for analysis of the tetralin and benzene cuts (see Results and Discussion). The column was Apiezon L supported on Chromosorb, operated a t 184 “C and a pressure of 25 psi; the flow rate of He carrier gas was 107 ml/min. Materials. The coal used in all experiments was a highsulfur, high-ash, h.v.a.b. Kentucky coal which has been used in Bureau of Mines pilot plant experimentation (Yavorsky et al., 1972) and which was kindly provided to us by the Bureau of Mines. Chemical and physical analyses of the coal are presented in Table I. Four Co-Mo-AlzO3 catalysts were used, all having a nominal composition of 3 wt % COO and 15 wt % MOOS (balance A1203). Two of these are commercial catalysts (Harshaw 0402T and Houdry HR-801), kindly furnished to us by the manufacturers. The other two were prepared by a “no-excess-solution,” two-step impregnation of two different controlled-pore-size y-aluminas, kindly furnished by Corning Glass Works. These aluminas had an exceptionally sharp pore size distribution. Each alumina was first impregnated with ammonium molybdate solution, dried, and calcined for 24 h a t 550 “C; and then impregnated with cobalt nitrate solution. dried, and calcined again for 24 h a t 550 “C. Some characterization data of the four Co-MoA1203 catalysts are contained in Table 11. Pore diameter distributions were determined by mercury porosimetry. More extensive studies of the catalysts based on the controlled-pore size aluminas are in progress and will be reported a t a later date (Parekh and Weller, unpublished results). All catalysts were ground and sieved before use. The sieve fractions employed were either 42-60 mesh (average particle diameter 0.030 cm), 48-60 mesh (average particle diameter 0.027 cm), or 20-28 mesh (average particle diameter 0.072 cm). The tetralin and methylnaphthalene employed as solvents were Eastman products, used without further purification. The benzene and pentane employed for separation of “ashphaltene” and “oil” were Fisher solvent grade, also used without further purification. Procedures. In a standard autoclave experiment, the autoclave (with glass liner) was charged with coal (75-80 g), solvent, and catalyst; evacuated; leak tested; charged with H2 (or N2) to a pressure of 1000 psia a t room temperature; and finally isolated from the H2 (or Nz) supply. The autoclave temperature was then increased to the desired operating temperature (405 or 455 “C) over a period of 1 h, held a t operating temperature for 1 h, and then allowed to cool (with use of a fan) to room temperature; the magnetic “dasher” was in operation only during the heatup and reaction periods. When the reactor had reached room temperature (usually with overnight cooling), the gas was slowly discharged through two caustic scrubbers t o absorb HzS, and then through a wet test meter. During this letdown, a sample of the gas was collected in a balloon to determine the gas density; the hydrocarbon gas production was calculated from the total gas density and volume.
Table I. Analyses of Kentucky Coal Ultimate Component
Pro xi m a t e %
Component
7c
Moisture 4.9 Moisture Ash (corrected for Ash sulfate and pyritic Volatile matter sulfur) 12.8 Fixed carbon Carbon 65.5 Hydrogen 4.9 Nitrogen 1.0 Sulfur (total) 4.64 as sulfate 0.61 as pyrite 2.59 as organic 1.44 Oxygen (by dif.) 6.3 Calorific value: 11 350 Btu/lb Apparent bulk density: 37 lb/ft3 Apparent particle density: 64 lb/ft3 Size: -100 mesh 100% -200mesh 70% Table 11. Characterization Data for Co-Mo-Al,O,
4.9 14.0 37.1 44.0
Catalysts
Total area, mZ/gaAv pore diam,d,~A Sample
Before After Before impreg. impreg. impreg.
After impreg.
Harshaw ,. . 1436 .. . 60 Houdry ... 277C ... 60,3500 Corning “large pore” 100 71 180 2 20 Corning “small pore” 170 128 90 120 a BET area after evacuation at 135 C. b Nominal area stated by manufacturer as 200 m’/g. CNominal area stated by manufacturer as 300 m*/g. This catalyst has an unusually broad pore size distribution, which is represented in the table as being approximately bimodal.
The reaction products and solvent inside the autoclave glass liner were filtered, and the solids were extracted in a Soxhlet thimble for 1 to 12 h (depending on the amount of solids) with a 5:l weight ratio of benzene to wet filtered solids. The extracted solids were dried in a vacuum oven and reported as “benzene insolubles.” The liquid was combined with the original filtrate and then distilled to 180-200 “C to give a “benzene cut.” The distillation was continued to about 245 “C in the case of runs with tetralin solvent to give a “tetralin cut,” or to about 280 “C in the case of runs with methylnaphthalene. The liquor remaining in the distillation flask was then mixed with a 5:l ratio of pentane to precipitate crude asphaltene. This crude asphaltene was again mixed with excess pentane and filtered again; the solid, after vacuum drying, is reported as “asphaltene.” The two pentane filtrates were combined and the pentane distilled off; the relatively light residue is reported as “oil.” Material balances, based on total coal charged, were usually within f3%. In a few cases, however, the material balance was off by almost 7%. The product distributions reported in the Results and Discussion section are based on total product actually obtained (including gas), rather than on total coal charged, in order to minimize the complicating effect of imperfect material balances. Elemental analyses (S, N, C, H) of the oil, asphaltene, and benzene insolubles were obtained through the courtesy of the Corning Glass Works. H2S absorbed in the caustic scrubbers was converted to sulfate by wet oxidation, followed by gravimetric determination as BaS04. In the initial runs with tetralin solvent, a white solid was observed to form in the connecting lines during distillation of the “tetralin cut” from the reaction products, as well as in the cooled cut. The solid was proved to be naphthalene Ind. Eng. Chem., Prod. Res. Dev., Vol. 15, No. 1 , 1976
25
Table 111. Coal Hydrodesulfurization in Tetralin Solventa ~~
Product distribution, wt % Run no.
T, “ C
Gas
Cat.,
P f,
%
%
%
%
%
040 +
%
psia
Liq.
Asph.
Oil
Gas
B.I.
A), %
1 2170 67.2 41.2 18.8 2.0 32.8 31 405 HZ 0 4130 74.7 41.3 24.2 4.6 25.3 37 455 N* 49.9 25.4 5.6 13.8 34 0 2960 86.2 T-3 455 HZ 1 2900 86.2 38.0 36.9 6.3 13.8 49 T-4 455 HZ 2885 89.4 27.2 50.7 6.7 10.6 65 455 H, 10 T-5 Initial (cold) gas pressure 1000 psia. All runs with 75 g coal, 42-60 mesh Harshaw 0402T catalyst (where used). Initial (cold) tetralin: coal ratio = 3.2 in Run T-1, 4.0 in others. Tetralin: coal ratio at run temperature = 2.3 (calcd). B.I. on catalyst-free basis. Product distribution based on actual material balance (B.I. + asphaltene + oil + gas + 4.9% moisture in coal). O / ( O + A) = ratio of oil to oil + asphaltene in liquid product. p f = measured total pressure after 1 hour at run temperature. Catalyst concentration based on coal.
T-1 T-2
by thin layer chromatography and by mixed melting point with a known sample. The lines were thereafter heated during distillation. For analysis of the condensed tetralin cut by gas chromatography, a sample was therefore diluted with 2 parts of acetone before injection into the chromatograph. Every sample proved to give four peaks on chromatographic analysis; the retention times showed these to be: (1) naphthalene; (2) tetralin; (3) one of the decalins (one peak only); and (4) some “unknown,” small in amount, with a retention time rather close to that of the decalin peak. For purposes of calculating mole percentages, the “unknown” was assumed to have the same molecular weight and GC calibration curve as decalin.
Table IV. Sulfur Contents of Product Fractions, Tetralin Solvent
Results and Discussion Hydrodesulfurization and Product Distribution with Tetralin Solvent. A series of scanning runs was made, all with 42-60 mesh Harshaw 0402T catalyst, to explore the effects of temperature, gas phase, and catalyst concentration. The results are summarized in Tables I11 and IV, and they present no surprises. A t 405 “C, even with Hz and catalyst, liquefaction is relatively low (though substantial in tetralin as solvent); the liquid product is largely asphaltene; and the residual sulfur content of both the oil and the asphaltene fractions is relatively high. Comparison of runs T-2 and T - 3 shows that the presence of gaseous hydrogen is important, even when tetralin, an excellent hydrogen donor, is used as solvent. Liquefaction is incomplete in nitrogen, and the extent of desulfurization is less in both oil and asphaltene fractions. These results are relevant to the “Solvent Refined Coal” (SRC) process, in which coal is extracted with a heavy aromatic solvent under moderate hydrogen pressure, but in the absence of catalyst. In the three runs, T-3, T-4, and T-5, in which catalyst concentration was varied from 0 to 10% of the coal charged, liquefaction in tetralin solvent was substantially complete in all cases. The minor variations indicated in Table I11 are not considered meaningful because of the high ash content (of which an important part is pyrite) in the original coal. The apparent liquefaction will be influenced by the extent to which pyrite is reduced during the run. The data in the last column of Table IV show that in all cases, a significant amount of pyritic sulfur is removed; the average for Runs T-3, T-4, and T-5 indicates that about 74% of the total inorganic sulfur is no longer present in the benzene insolubles (which contains the ash, as well as the catalyst). Mr. Herman Taylor, Jr., of the Gulf Research and Development Company, has very kindly informed the authors that over 80% of the inorganic sulfur is removed in the Gulf catalytic coal liquefaction process, a typical figure being 83% (H. Taylor, personal communication). Much more pyritic sul-
Table V. Distribution of Tetralin, Naphthalene, and Decalin
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Ind. Eng. Chem., Prod. Res. Dev., Vol. 15, No. 1, 1976
Wt % S in: Run no.
Cat., T, ” C
Gas
%
Asphal- Wt S, g, tene in B.1.Q
Oil
T-1 H, 1 0.41 405 0 0.34 T-2 N, 455 T-3 0 0.25 H, 455 T-4 1 0.21 H, 455 T-5 455 H, 10 0.093 aTotal weight of sulfur in 75 g of,coal = 1.08 g is organic and 2.40 g is inorganic.
1.21
1.45 1.34 0.80 0.47 0.52 0.47 0.25 0.58 3.48 g, of which 1.10
Mol %a Run no.
T, “C
Gas
T-1 T-2 T-3 T-4
405 455 455 455
H, N, H, H,
Cat., Tetra- Naphtha- Deca- “Un% lin lene lin known” 1 0 0 1
84.4 46.4 47.1 41.5
9.8 27.8 24.7 21.2
3.2 19.6 20.5 28.9
2.7 6.2 7.8 8.4
28.7 19.1 ... ] b [Calcd equil. at 455°C: 52.2 Retention times (min) in GC analysis: naphthalene, 5.73; tetralin, 4.76; decalin, T-1,2,3,4, 3.04 (one peak only); decalin (Eastman), 3.04, 3.79 (two peaks); “unknown,” 2.41. b Equilibrium (vapor phase) calculated from data of Frye (1962) and Egan (1963), including the formation of both trans- and cis-decalin. fur is removed a t 455 than a t 405 “C, of course, but even a t 455 OC and in tetralin the removal is substantially greater in Hz than in Nz (T-3 vs. T-2, Table IV). The largest effect of catalyst concentration on sulfur removal is in the sulfur contents of oil and asphaltene (Table IV); especially a t 10% catalyst, the sulfur content of both fractions is quite low. The other major effect of catalyst concentration a t 455 “C is on product distribution. The ratio of oil to oil plus asphaltene shifts from 34% in Run T-3 (Table 111), with no catalyst, to 65% in Run T-5, with 10% catalyst. In summary, these results show that even though tetralin is an excellent hydrogen-donating solvent, the presence of gas phase hydrogen and of Co-Mo-AlZOs catalyst play very important roles both in the conversion of asphaltene to oil and in the extent of desulfurization. Disproportionation of Tetralin. As indicated in the introduction, although the hydrogen-donor properties of tetralin in coal solvation have been long known, little attention has been given to the possible occurrence of the disproportionation of tetralin to naphthalene and decalin
Table VI. Coal Hydrodesulfurization in Methylnaphthalene Solventa Product distribution, wt % Run no. MN-1 MN-2 MN-3 MN-4 MN-5 MN-6 MN-7
Catalyst Corning A1,0, Corning A1,0, Corning A1,0, Corning A1,0, Houdry Harshaw (None)
base base base base
d, A
5,cm
220 220 120 120 (60,3500) 60
0.072 0.027 0.072 0.027 0.030 0.030
% Liq.
% Asph.
% Oil
5% Gas
% B.I.
O / ( O + A)
71.2 33.0 25.3 8.0 28.8 43.4 46.6 71.5 31.2 27.2 8.3 28.5 21.2 9.6 33.2 40.3 66.8 31.3 9.7 32.8 44.1 23.3 67.2 29.5 34.6 33.8 17.8 9.8 33.8 66.2 64.8 28.5 21.7 9.7 35.3 43.2 43.1 18.3 15.5 4.4 56.9 46.0 a Initial (cold) gas pressure 1000 psia. All runs with 80 g of coal, H, gas, 1%catalyst (except for MN-7, a blank run with no catalyst) based on coal. Methylnaphtha1ene:coal ratio at run temperature = 2.3 (calcd). B.I. o n catalyst-free basis. Product distribution based on actual material balance. 0/(0 + A) = ratio of oil to oil + asphaltene in liquid product. All runs for 1 h at 455 "C. Table VII. Sulfur Contents of Product Fractions, Methylnaphthalene Solvent Table V summarizes the molar composition of the tetralin distillation cuts (including a small amount of these components found in the benzene distillation cuts) found by GC analysis for a number of the coal hydrodesulfurization runs listed in Tables I11 and IV. Also in Table V is a calculated equilibrium composition for the disproportionation reaction in the vapor phase at 455 "C, deduced from data given by Frye (1962) and Egan (1963). (The calculated compositions do not vary greatly between 600 and 800 OK.) More work on the disproportionation reaction should be carried out because of its intrinsic interest. Since the matter could not be pursued further in the present investigation, the results obtained to date are presented in Table V in spite of some residual questions of interpretation. The principal conclusions (and residual problems) from Table V are the following. (1) Disproportionation occurs relatively slowly a t 405 "C, even in the presence of CoMo-AlzOs; the amounts of naphthalene and decalin are far less than those corresponding to equilibrium. (2) Disproportionation appears to occur rapidly a t 455 "C with or without catalyst, and it should be considered in accounting for the behavior of hydroaromatic solvents in coal processing. (3) In the absence of catalyst, disproportionation a t 455 "C occurs relatively independently of the gas present (Nz vs. Hz), and the naphtha1ene:decalin ratio is not far from the predicted 3:2. (4) In the presence of Hz and CoMo-AlzOs, hydrogenation of napthalene (and possibly of tetralin) occurs a t 455 "C, with the formation of a disproportionately high amount of decalin. (5) The identity of the "Unknown" listed in Table V should be established. (6) The reason for the occurrence of only one of the decalins in these runs should be investigated. The data suggest t h a t the disproportionation may be occurring by a stereospecific mechanism. Hydrodesulfurization and Product Distribution with Methylnaphthalene Solvent. The data shown in Tables I11 and V indicated that tetralin was not an ideal solvent for these studies for two reasons: (1) the very high degree of liquefaction obtained with 1% catalyst, Hz, and 1 h a t 455 "C (Run T-4, Table 111)makes it difficult t o differentiate the comparative effects of catalyst variables; and (2) the occurrence of the disproportionation reaction complicates interpretation of the role of solvent. Subsequent experiments were therefore made with (mixed 1- and 2-) methylnaphthalene as solvent. The results are summarized in Tables VI-VIII. All of the runs in methylnaphthalene were conducted with a hydrogen atmosphere, for 1 h a t 455 "C, and with a cata1yst:coal ratio of 0.01:l (except for the blank run MN-7, in which catalyst was omitted). Comparison of Tables I11 and VI, and of IV with VII, leads to the following conclusions.
Wt % S in: Run n0.a MN-1 MN-2 MN-3 MN-4 MN-5 MN-6 MN-7 a See Table VI for
Oil
Asphaltene
0.23 0.30 0.25 0.23 0.24 0.33 0.39 description of
Wt s, g, in B.I.
1.62 0.56 0.60 1.57 1.68 0.49 0.57 1.57 1.53 0.95 1.49 0.85 0.74 2.42 catalysts and conditions.
Table VIII. Factorial Analysis of Runs MN-1, 2, 3, 4 Main effects Quantity % Liquefaction
O / ( O + A)
Increase in d
Decrease in D
Interaction
+4.4% +3.0%
+0.4% +4.0%
0.1% 0
1. Liquefaction is incomplete in all runs with methylnaphthalene. 2. Comparison of Run T - 4 (Tables I11 and IV) with Run MN-6 (Tables VI and VII), both of which were made with 1% Harshaw 0402T a t the same reaction conditions (except for solvent), shows that in methylnaphthalene liquefaction is lower, gas production somewhat higher, and sulfur content substantially higher (especially in the asphaltene fraction) than in tetralin. 3. Very poor liquefaction is obtained in methylnaphthalene in the absence of a catalyst under these conditions (Run MN-7, Tables VI and VII), although the oi1:asphaltene split and the S contents of these fractions is not grossly different than those obtained with some runs with catalysts. Comparison of Run MN-7 with Run T-3 (Tables I11 and IV) shows the importance of the hydrogen-donating property of tetralin vs. methylnaphthalene, in the absence of catalyst. 4. Compared a t about the same particle size, the two catalysts based on Corning controlled-pore aluminas were somewhat superior to the two commercial samples tested, in the sense of slightly higher liquefaction and considerably lower S in the asphaltene fraction. This result should not be generalized until many more commercial samples have been tested. 5. The four runs represented by MN-1 to MN-4 were set u p as a 2 X 2 factorial design, in which average pore diameter and average particle size were the two factors. As Table VI1 indicates, the variations in S content of oil and asphalInd. Eng. Chem., Prod. Res. Dev., Vol. 15,No. 1, 1976
27
tene fractions were not significant. However, Table VI11 shows the results of a factorial analysis for the degree of liquefaction and the asphaltene to oil conversion. The main effects-increase in liquefaction and in oil production with increase in pore diameter and with decrease in particle size-were shown by analysis of variance to be statistically significant a t the 90% level or higher. Interaction between these factors appeared to be negligible. 6. The results in Tables VI and VI11 imply that with CoMo-Al203 catalyst, the rates of both liquefaction and conversion of asphaltene to oil are strongly pore-diffusion limited. The beneficial effects of larger pore diameter (e.g., MN-1 vs. MN-3, and MN-2 vs. MN-4, Table VI) occur in spite of the fact that the total surface area of the large pore diameter catalyst is substantially lower than that of the small pore material (71 vs. 128 m2/g, Table 11). Further studies are planned on controlled-pore aluminas having diameters larger than 180 A, when these become available. 7. The preceding conclusion also implies that the effectiveness factor is low for high area Co-Mo-A1203 in this application. This suggests the desirability of preparing and testing catalysts in which the transition metal compounds (Co, Mo oxides and sulfides) are introduced in such a way as to be preferentially concentrated near the external surface of the catalyst particles or pellets.
Acknowledgment The authors are grateful to the Houdry Laboratories and to Harshaw for kindly supplying catalyst samples, and to the Corning Glass Works both for partial support of this research and for supplying a number of the analytical results reported in this work.
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Res. Dev., Vol. 15,No. 1, 1976
Literature Cited Akhtar, S., Friedman, S.. Yavorsky, P. M., U S . Bur. Mines Bull., No. 35 (July 1971). Akhtar. S.. Friedman, S., Yavorsky, P. M., 71st National Meeting, AIChE. Dallas, Texas, Feb 20-23, 1972. Clark, E. L., Pelipetz. M. G.. Storch, H. H., Weller. S., Schreiber, hd. Eng. Chem., 42, 861 (1950). Donath, E. E., "Hydrogenation of Coal and Tar," "Chemistry of Coal Utilization," Suppl. Vol., pp 1048-1053, Wiley, New York. N.Y.. 1963. Dryden, I. G. C.. Fuel, 29, 197, 221 (1950). Dryden, I. G. C., "Chemical Constitution and Reactions of Coal," "Chemistry of Coal Utilization," Suppl. Vol., pp 237-240, Wiley. New York. N.Y.. 1963. Egan, C. J., J. Chem. Eng. Data. 8 (4), 532 (1963). Frye, C. G., J. Chem. Eng. Data, 7 (4). 592 (1962). Kawa. W.. Friedman, S.,Wu. W. R. K., Frank, L. V., Yavorsky. P. M., 167th National Meeting of the American Chemical Society, Los Angeles, Calif., Mar 31-Apr 5, 1974. Oele. A. P., Waterman, H. I.. Goedkoop, M. L., van Kreveien, D. W., Fuel, 30, 169 (1951). Orchin, M., Storch, H. H., lnd. Eng. Chem., 40, 1385 (1948). Pelipetz. M., Kuhn. E. M., Friedman, S., Storch, H. H.. Ind. Eng. Chem., 40, 1259 (1948). Pelipetz, M., Weller. S., Clark, E. L.. Fuel, 29, 208 (1950). Pott, A,, Broche, H., Schmitz. H., Scheer, W.. Gluckauf, 69, 903 (1933). Taylor, H.. Jr., Gulf Research and Development Co., Pittsburgh, Pa., private communication, 1974. Weller, S.. Pelipetz, M. G., Kuhn, M., Friedman, S., Clark, E. L., lnd. Eng. Chem., 41, 972 (1949). Weller, S., Pelipptz, M. G.. Friedman, S., Storch, H. H.. lnd. Eng. Chem., 42, 330 (1950a). Weller, S..Clark, E. L., Pelipetz, M. G., lnd. Eng. Chem., 42, 334 (1950b). Weller. S., Peiipetz, M. G., lnd. Eng. Chem., 43, 1243 (1951). Weller. S., Pelipetz. M. G., Friedman, S., hd. Eng. Chem., 43, 1572 (1951a). Welier, S.. Pelipetz. M. G.. Friedman, hd. Eng. Chem., 43, 1575 (1951b). Weller, S., Pelipetz, M. G., Proc. 3rd WorMPetrol. Cong., Sect. IV, Subsect. I, 91 (1951~). Wiser, W. H., Fuel, 47, 475 (1968). Wiser, W. H.,Anderson, L. L., Qader, S. A,. Hill, G. R., J. Appl. Chem. Blotechno/., 21, 82 (1971). Wu, W. R. K., Storch, H. H.,US. Bur. Mines Bull., No. 633 (1968). Yavorsky. P. M., Akhtar. S..Friedman, S..65th Annual Meeting, AIChE, New York, N.Y., Nov 26-30, 1972.
Received for review January 6, 1975 Accepted November 13,1975
