Hydrogenation of High-Volatile Bituminous Coals Summary of Assays of Bituminous Coals, Subbituminous Coals, and Lignites L. L. HIRST, R. L. BOYER, A. EISNER, I. I. PINKEL, AND H. H. STORCH Central Experiment Station, U. S.Bureau of Mines, Pittsburgh, Penna.
EC-USE of high yield of oil and comparative freedom from certain operating difficukies, the hydrogenation of high-volatile bituminous coals is of special interest. I n a previous paper of this series ( 6 ) the results of hydrogenation of the following coals of this type were presented: High-volatile -4coals from the Mary Lee (Ala.) and the Pittsburgh (Penna.) beds, high-volatile B from the Illinois No. 6 bed, and high-volatile C from the McKay (Wash.) bed. The present paper describes the hydrogenation of similar coals: High-volatile A coals from the Upper Freeport (W. Va.) and the Black Creek (Ala.) beds, high-volatile B from the Lower Sunnyside (Utah) bed, and high-volatile C from the Indiana No. 4 bed. The hydrogenation assays were conducted in the experimental plant erected by the Bureau of Mines at Pittsburgh. This plant has been described in previous publications (5, 6, 8, 9, 10). The assay procedure comprises pumping a mixture of about equal parts of powdered coal and a heavy oil with hydrogen under 200 to 300 atmospheres pressure into a vertical alloy-steel tube, 3 inches i. d. and 8 feet long, heated to 430-450" C. (806-842' F.). The contact time and temperature are varied until a maximum yield of oil, carried out of the converter by the stream of hydrogen, is obtained. A heavy oil, in which are suspended the ash of the coal, the unreacted coal, and the catalyst particles, is discharged through a standpipe about 6 feet above the bottom of the converter. This heavy-oil slurry is centrifuged, and the resulting oil is mixed with another charge of coal and catalyst. Thus the assay consists essentially in determining the optimum conditions for the maximum yield of oil consistent with complete regeneration of the tar-oil vehicle used in making a paste with the original coal. The assay product comprises about 20 per cent of oil boiling in the gasoline range (to 205" C.) and 70 per cent boiling from 205-330" C. (401-626' F.). This oil contains 12-20 per cent of tar acids and 2-4 per cent of tar bases. The
B
remainder, or neutral oil, is 40-70 per cent aromatic and contains 20-40 per cent saturates and 10 per cent olefins. The saturates are 50-90 per cent naphthenic, and the olefins are cyclic. Table I summarizes the yield of oil and residue for all coals thus far hydrogenated in the experimental plant. Column 4 shows that, with two exceptions, there is a steady decrease in the yield of oil, based on the moisture- and ashfree coal, with decreasing coal rank. The coal of highest rank gave a lower yield than might be predicted, and the Monarch subbituminous coal yielded appreciably more oil than was expected from a coal of this rank. The yield based on dry coal is somewhat erratic owing to varying amounts of ash, and that based on the coal as mined also shows eccentricities due to the ash content as well as to the influence of the moisture content, which results in a more rapid drop with decreasing rank. The petrographically estimated amounts of organic residue in column 7 agree reasonably well with those of column 8, which were obtained in the experimental plant. Table I1 shows the quantity of tar acids, tar bases, neutral aromatic oils, and gas obtained in the coal hydrogenation assays, as well as the quantity of hydrogen consumed. The oxygen and nitrogen content of the coals may be correlated to a limited extent with the yield of tar acids and tar bases, respectively. There is no apparent explanation for the outstanding high yield of tar acids from Pittsburgh bed coal. The low tar acid yield for the Upper Freeport and the Black Creek coals is probably due to the higher operating temperatures used in hydrogenating these coals (Table IV). These temperatures ranged from 455-460" C. (851-860' F.),
TABLEI. YIELDOF RESIDUE AND OIL 19 THE EXPERIMENTAL PLAXT 1 Coal Ranka H. V. A bit. H . V. A bit. H. 7. A bit. H . V. A bit. H . V. B bit. H. V. C bit. H . V. B bit. H. V: C bit. Subbit. B Subbit. B Subbit. B Lignite Lignite a
2
3
Hs0, yo of Bed and State Coal as Mined Mary Lee, Ala. 4.2 3.2 Upper Freeport, W.Ca. Pittsburgh, Penna. 1.6 2.7 Black Creek, Ala. 5.5 Lower Sunnyside, U'tah No. 4, Ind. 13.6 No. 6 I11 7.8 McKAy, b a s h . 9.6 Puritan, Colo. 24.1 Rosebud, iMont. 25.1 Monarch, Wyo. 23.2 Beulah, N. Dak. 34.0 Velva, N . Dak. 39.5
H.V. = high-volatile; bit.
5
4 Moisture- and Ash-free coal 60 70 70.5 70.5
Yield of Oil, yo
75
70 70.5 68.5 63 60 68.5 56.5 52
Dry coal 54 64 65 68 71 64 65 66 BO
55 64 50 49
= bituminous: subbit. = subbituminous.
1068
6
Coal as mined 52 62 64 66 67 55 60 59 45 40 49 31 32
7
70of
8
9
9.8 5.1 4.0 6.0 5.0 5.5 4.9 1.1 5.6 6.7 3.1 9.7 4.7
Ash 10.2 8.3 5.7 2.9 5.2 8.5 7.1 4.1 5.4 10.1 5.1 12.3 7.4
Dry Coal Organic Residues Predioted Obtained
9.0 3.4 7.8 7.8 5.4 6.8 6.4 0.5 4.2
8.2 2.6 7.6 6.6
August, 1941
INDUSTRIAL AND ENGINEERING CHEMISTRY
1069
whereas 430440" C. (806TABLE11. HYDROGEN USED AND YIELD O F TARACIDS, TARBASES,AND TOTAL AROMATIC 824" F.) was employed for NEUTRAL OIL most of the other coals. The 1 2 3 4 5 6 7 8 9 10 tar acids boiling to 235" C. --Tar AcidsTotal Hydro-DistillingAromatic (455" F.) are approximately gen Total To 235NitroTar Neutral half of the total phenolic comCoal Bed and State Oxygen Used yield 235O C. 300' C. gen Bases OiP Gas nounds and comnrise about Per cent of moisture- and ash-free coal 2.6 2.5 32.8 5.0 4.3 1.8 8.5 7.6 50 per cent xylenols, 30 2.1 34.8 12.0b 5.3 5.7 2.9 1.5 2.0 Va. cresols, and 20 phenol. Per3.7 40.9 7.5 1.7 2.8 9.0 12.2 6.8 30.8 1.7 12.1b 8.4 2.5 7.5 4.1 1.8 haps the most significant 7.5 10.9 tah 4.0 29.8 9.5 5.1 1.6 2.6 4.3 31.5 5.6 1.7 2.3 9.0 11.7 9.5 data in Table I1 to be correNo. 6 I11 10.0 8.5 15.1 4.2 37.1 6.0 1.9 1.7 lated with rank are those of 27.7 6.0 5.0 2.2 3.7 12.5 7.6 14.6 McK& Wash. 28.2 4.2 1.6 2.8 Puritan: C O ~ O . 9.7 12.6 7.4 16.4 column 9 for the total aro26.4 2.1 16.2 7.5b 13.8 1.1 7.6 5.4 Rosebud, Mont. 25.4 16.9 6.0 1.6 8.2 3.1 8.56 17.2 Monarch, Wyo. matic neutral oil. With two 23.5 Beulah, N. Dak. 19.4 8.0 12.0 5.6 5.2 1.0 1.6 outstanding exceptions 22.1 Velva, N. Dak. 21.2 7.0b 15.6 1.0 1.6 8.4 6.3 (Pittsburgh and Illinois No. 6 a I n calculating total aromatics i t was assumed that overhead oil boiling over 330' C. of Table V was 80 per oent aromatic. beds) there is a steady deb Assayed st 4500 pounds per square inch hydrogen pressure; all other tests a t 3200-3350 pounds. crease in yield of aromatic oil with decreasing rank. Column 3 shows th% there Geology, Petrography, and Chemical Analysis is little, if any, trend with coal rank in the amount of hydrogen used per unit weight of moisture- and ash-free A sample of high-volatile A bituminous coal from the Upper coal. The assays run at a hydrogen pressure of 4500 pounds Freeport bed was obtained from the Industrial Collieries per square inch consumed more hydrogen than those conCorporation No. 21 mine, Monongalia County, T.V. Va. This ducted a t 3200 pounds. This increased consumption was coal contains about 67 per cent fixed carbon on a moisturemore marked for the coals of higher rank. The hydrogen and ash-free basis (Table III), which is close t o the maximum used per ton of oil produced (column 3, Table 11, divided by of 69 per cent set for high-volatile A coals. The geology column 4, Table I) ranges from about 0.12 ton for bituminous and petrography of this bright coal were described in a recent coals to 0.15 for lignites, with the highest values about 0.17 publication (3); the major petrographic constituents are ton for the two bituminous coals hydrogenated a t 4500 anthraxylon and translucent attritus, both of which are pounds per square inch. The increase from 0.12 t o 0.15 ton liquefiable with high yield (Table 111). of hydrogen per ton of oil is much smaller than might have been predicted from the oxygen content (column 2, Table 11) of the coals. This result is apparently due to removal of most of the oxygen as carbon dioxide rather than as water TABLE 111. PETROGRAPHIC AND CHEMICAL ANALYSIS(PERCENT) for oxygen content greater than about 10 per cent ( 4 ) . Coal Constituents
Upper Freeport, W. Va.
Black Creek, 41a.
Lower Sunnyside, Utah
No: 4, Indiana
5.5 39.2 50.4 4.9
13.6 34.2 44.9 7.3
5.4 77.8 1.5 9.1 1.0 5.2
5.3 74.0 1.6 8.6 2.0 8.5
5.7 82.1 1.6 9,5 1.1
5.7 80.9 1.7 9.5 2.2
30 61 6 3
65 24
Coal as Received
The results are given of liquid-phase hydrogenation assays in the Bureau of Mines experimental plant of four additional bituminous coals : high-volatile A coals from the Upper Freeport (W. Va.) and the Black Creek (Ala.) beds, high-volatile B coal from the Lower Sunnyside (Utah) bed, and high-volatile C coal from the Indiana No. 4 bed. A summary is presented of the results with eight bituminous coals, three subbituminous coals, and two lignites. The yield of tar acids increases with decreasing rank from about 6 per cent (of the moisture- and ash-free coal) for the high-volatile bituminous coals of highest rank to about 16 per cent for subbituminous coals of lowest rank and for lignites. About half of the tar acids boil below 235 C. at atmospheric pressure. Of these low-boiling tar acids about 50 per cent is xylenols, 30 per cent cresols, and 20 per cent phenol. The neutral oil boiling above 188 C. contains only small amounts of paraffins and consists mainly of aromatics and naphthenes. About 7 per cent of cyclic olefins is present. The neutral oil boiling in the range 20-188" C. contains about 33 per cent saturated paraffins, 8 olefins, 38 naphthenes, and 21 aromatics. The yield of neutral oil is about 60 per cent (of the moisture- and ash-free coals) for bituminous coals, 50 for subbituminous coals, and 38 for lignites.
Moisture Volatile matter Fixed carbon Ash
3.2 29.2 59.3 8.3
Hydrogen Carbon Nitrogen Oxygen Sulfur Ash
4.9 79.4 1.4 5.2 0.8 8.3
2.7 36.4 59.1 2.8
Moisture-Free Coal 5.3 82.0 1.7 7.3 0.8 2.9
Moisture- and Ash-Free Coal Hydrogen Carbon Nitrogen Oxygen Sulfur
5.3 86.6 1.5 5.7 0.9
Anthraxylon Translucent attritus Opaque attritus Fusain
67 26 6 1
5.4 84.4 1.8 7.6 0.8
Petrographic Analysis" 45 3s 7 5
7
4
a Based on microscopic estimation of areas in numerous thin sections made from a vertical column of coal cut from a working face of the coal seam.
The Black Creek, high-volatile A, bituminous coal sample was obtained from the washer a t the De Bardeleben Coal Corporation's Empire mine, Walker County, Ala. It was X 0 inch coal collected in small increments every 4 minutes over a period of 8 hours. This coal is of somewhat lower rank than that from the Upper Freeport bed. I t s chemical and petrographic analyses are given in Table 111. A dis-
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 33, No. 8
TABLE IV. HYDROGENATION YIELDDATAFOR HIGH-VOLATILE BITUMIXOUS Coats [Catalyst, 0.05 per oent CHI8
1 Run and Generation N ~ . 66-3 66-5 67-7
67-8 63-4 64-5 64-6 64-8 60-8 61.9 61-11
2
Reaction Conditions Temp., 0 c. ( 0 F.) 451 (843.8) 453(847.4) 460(860)
464(867.2) 450(842) 448(838.4) 454(849.2) 455(851)
446(834.8) 439(822.2) 440 (824)
445(830) 451 (843.8) 451 (843.8) 70-9 a The hydrogen absorbed
6s-6 70-8
+ 0.1culation per cent SnS; paste-pumping rate, 7.0 t o 7.3 pounds per hour: reflux temperature, 292-303' rate, 250-300 cubic fee%per hour: duration of each generation, 20-30 hours] 3
4
Pressure, 1b.I sq. In.
~ ~ Overhead to Heavy Oil
3300 4500 4500 4500
0.44 0.45 0.50 0.55
3300 4500 4500 4500 3300 3300 3300
0.40 0.40 0.50 0.50 0.49 0.32 0.33
5 6 7 8 Moisture~ i and~ Ash-Free , Coal Hz absorbed, % Water and water Organic Gas sol. solids Oil
+
31.8
29.3 27.6 22.2
20.1 22.4 20.6 19.8
14.9 12.8 13.0
3.6 3.1 5.8 6.6 7.4 8.4 9.6 8.7 13.8 10.9
12.6
19.5 9.0 3300 0.37 21.4 10.3 3300 0.45 18.8 10.6 3300 0.52 in the first and second generations a t
9
10
Upper Freeport 3.9 61.0 12.Za 3.2 63.8 11.7 5.1 62.4 12.0 5.7 64.5 10.0 Black Creek 64.6 70.1 62.2 64.0
68.6 71.0 70.0
71.0
7.7 9.4 11.0 13.2
69.S 77.0 68.9 72.3
Lower Sunnyside 4.8 65.6 6.8 7.1 69.2 7.2 4.9 10.1 7.5
70.1 74.2 75.3
6.8 7.5 6.0 5.7
11
Moisture- and Ash-Free Coal, % HydroTar genabOil acid sorbed yield yield
12
13
Overhead Oil, Vol. yo Tar Tar acids bases
C. (558-572" F,);gas cir14
5.0 6.0
cussion of its geology and petrography was published (2). Frequent occurrence of thin fusain bands results in a moderately high fusain content. Apparently, grinding and washing reduced the fusain content appreciably, as the '/? x 0 inch sample contained only 5 per cent of fusain, mThereas the column sample is reported ( 2 ) to contain 10 per cent. 4 sample of high-volatile B coal from the Lower Sunnyside bed was obtained from the Columbia Steel Company's Columbia mine, Carbon County, Utah. This coal differs from the other bituminous coals hydrogenated in that translucent attritus predominates and a considerable quantity (about 10 per cent) of resins is present. A detailed petrographic study of the coal was published (11). The bulk of the Lower Sunnyside coal was derived from coniferous plants rather than from lycopods or cycadophytes, the remains of which comprise the major parts of the other bituminous coals chosen for hydrogenation. The fourth coal sample was taken from the Indiana KO. 4 bed, Walter Bledsoe & Company's Saxton No. 1 mine, Vigo County, Ind. Although of high-volatile C rank, this coal has about the same oxygen content as that from the Lower gunnyside bed. The Indiana No. 4 bed is a fairly uniform bright coal whose petrography ( 1 ) is much the same as that of most of the high-volatile bituminous coals in the Appalachian field. O p e r a t i n g Difficulties a n d Yields In beginning the coal hydrogenation assays, coal tar from cokillg of Illinois KO. 6 coal in Knomles ovens was used for the first batch of vehicle or pasting oil. After the third generation (generations are periods of 20 to 30 hours during heavy-oil slurry is centrifuged and the heavy oil stored for use in making up the next batch of coal-oil paste), a vehicle characteristic of the coal was formed. The ratio of coal to pasting oil ranged from 1.0 to 0.7, depending on the ease of pumping and the steady-state concentration of insolubles in the heavy 011, whlch usually was about 12 per cent. The heavy-oil slurry from the Upper Freeport coal was quite viscous, and some dilution was necessary before centrifuging. During eight generations the operating tempera-
16
Neutral Overhead Oil, 1'01. y: AroSatumatics rates
Olefins
7.4 6.4 5.3 5.1
10.8 9.0 7.5 7.2
2.7 2.4 2.7 2.8
6.2 6.0 5.2 5.0
56 4 556 54.0 55.0
40.0
9.1
13.1 12.0 11.4 11.6
2.9 3.0 2.8 2.4
7.0 7.0 6.4 6.4
52.0 50.4 52.2 52.6
41.0 42.6 41.4 41.0
14.3 16.0
3.0 3.2 3.4
8.5 10.0 8.4
48.5 60.0 47.2
43.0 40.0 44.4
62.0 55.2
39.0 36.0 36.0
9.2
7.9 8.4
10.1 11.9
10.7
14.2
Indiana KO.4 66.4 10.3 73.0 11.7 16.0 3.6 9.0 62.4 10.1 69.0 10.1 14.6 3.4 8.8 64.1 8.8 10.4 70.0 14.8 3.2 8.4 3300 pounds per square inch was 9.1 and 9.8 per cent, respectively
4.7
15
85.6
37.4 38.4 40.8
ture was increased from 440' to 464" C. (824" to 867.2" F,). The chief effects of this increase were a somewhat lower viscosity of the heavy-oil slurry, an increase in the ratio of overhead to heavy oil, a marked decrease in the fraction boiling over 330" C. (626' F.) in the overhead oil, and a decrease in the tar-acid content of this oil from 10.8 to 7.2 per cent. In the fourth generation the pressure was increased from 3300 to 4500 pounds per square inch. The average of the hydrogenconsumption percentages for the first three generations was about 10.0, while that for the fifth, seventh, and eighth generations was 11.2. KO other effect was observed that could be direct'ly attributed to the increased hydrogen pressure. Yield and analytical control data representing the optimum condit.ions for the four bituminous coals are presented in the last two r o w under each coal in Tables IV and V. Thus for the Upper Freeport coal t.he seventh and eighth generation conditions are considered optimum. Data for the third and fifth generations are also included in Tables IV and V for comparison of the coals a t constant temperature. The additional data also indicate the decrease in tar acid vield with increasing temperature. (See column 11,Table 117.) During the sixth, seventh, and eighth generations of hydrogenation of the Freeport coal, 0.20 per cent ILl[Ooo, 0.50 , 0.20 per cent each of Mooe and MoS2, per cent M o O ~ and respectively, were added as catalysts, in addition to 0.05 per cent CHI3and 0.1 per cent SnS. As far as could be observed, these additions of molybdic acid and molybdenum disulfide had no effect on the yield or the physical and chemical characteristics of t'he product. During the first and second generations of the Black Creek coal, some paste-pumping difficulties were experienced owing t o deposition of a shellaclike material on the check-valve seats of the paste pump. This difficulty disappeared in subsequent generations as the Illinois No. 6 tar vehicle was replaced by one characteristic of the Black Creek coal. TO obtain a heavy oil that was sufficiently fluid, it was necessary to operate a t 458" C. (851' F.). At this temperature, dilution of the heavy-oil slurry was necessary with about 5 per cent of bottoms from the distillation of the overhead oil. A change from 3300 to 4500 pounds per square inch operating pressure of hydrogen was made in the fifth generation. This
I N D U S T R I A L A N D E N G I N E E R I N G CHEM1STR.Y
August, 1941
change increased the consumption of hydrogen from 7.7 to 9.4 per cent. No other effect on yield or character of products was observed. Comparison of the tar acid yield a t 450451" C. (842-843.8" F.) of the Black Creek and the Upper Freeport coal shows about 25 per cent larger yield for the Black Creek coal. The hydrogenation assay of Lower Sunnyside coal was begun a t 425" C. (797" F.) and the temperature increased gradually to 446" C. (834.8' F.) in the eighth generation. The viscosity of the heavy oil decreased with a n increase in operating temperature until at 440" C. (824" F.) the heavyoil slurry was fluid enough so that no dilution was necessary before centrifuging. Some changes were made in the quantity of iodoform added as a catalyst in hydrogenating this coal, but little, if any, effect was noted when the quantity of iodoform was increased from 0.05 to 0.15 per cent. Although 440" C. was chosen as the optimum operating temperature for this coal, data a t 446" C. (generation 8, Tables IV and V) are also included for comparison with data on Indiana No. 4 coal a t constant temperature. Such a comparison indicates a significantly lower tar acid yield (column 11, Table IV) for the Lower Sunnyside coal, whereas a similar comparison a t optimum operating temperatures shows a somewhat lower yield for the Indiana No. 4 coal. I n general, the Lower Sunnyside coal gave the least difficulty in hydrogenation of the four coals described in this paper. Probably the relatively high yield of oil is due largely to the low optimum operating temperature. The first-generation paste for the Indiana No. 4 coal was very stiff and difficult to pump. Although quite fluid when first prepared, it thickened considerably when agitated. The second-generation paste was much more fluid, and the thirdgeneration paste was quite satisfactory for normal pump operation.
Characterization of Oil Products of Liquid-Phase Hydrogenation of Bituminous Coals Tables IV, V, and VI give analytical data on overhead oils. The variation of tar acid content with operating temperature (Table IV) and rank of coal (Tables I and IV) has already been discussed. The concentration of aromatic hydrocarbons in the neutral-oil product is about 55, 52, 48.5, and 55 per cent for the Upper Freeport, Black Creek, Lower
Sunnyside, and Indiana No. 4 coals, respectively. The total yield of aromatics (Table I) is 34.8, 30.8, 29.8, and 31.5 per cent, respectively, of the moisture- and ash-free coals. The Indiana No. 4 coal apparently yields appreciably larger quantities of aromatics than would be expected from its rank. Inspection of columns 2 and 15 of Table IV indicates that the aromatic content of the neutral oils varies little, if any, with reaction temperature. The distillation data of Table V show no trend with either rank of coal or temperature of operation. Ae observed in a previous publication ( I ) , the most important variables in determining the distillation characteristics of the overhead oil are the reflux temperature and the rate of passage of hydrogen gas into the converter. Both factors were held constant during the runs of Table V. To obtain information on the boiling-point distribution of tar acids, aromatics, and other constituents of the overhead oils, proximate analyses were made of fractions boiling in the temperature ranges 20-188", 188-207", 207-235") 235-270", and 270-300" C. (68-369', 369-405", 405-455", 455-518", and 518-572" F.) the first three of which correspond to the boiling ranges of phenol, cresols, and xylenols in mixtures with aromatic hydrocarbons. These distillations, as well as those of Table V, were made through a 6-inch, indented, glass distillation column of the Vigreux type, and the data are given in Table VI. From the refractive indices of the saturated-oil fractions the naphthene content was estimated for the 20-188" and 188-207" C. fractions by the method of McArdle and his collaborators (7). The higher boiling fractions were entirely naphthenic, and the number of rings per molecule was estimated by comparison with the refractive indices of pure naphthenes boiling in the same temperature ranges. The tar acid figures of Table VI show that higher concentrations of these acids are obtained from hydrogenation of Indiana No. 4 and Lower Sunnyside coals than from that of the higher rank Upper Freeport and Black Creek coals. Table VI1 gives the percentage of phenol, cresols, and xylenols in the tar acids boiling below 235" C. for all of the high-volatile bituminous coals hydrogenated in the Bureau of Mines experimental plant. The distillation data for the Mary Lee, Pittsburgh, Illinois No. 6, and McKay coals are contained in a previous publication (1). No apparent trend with rank is observable in Table VII. I n general, about 50
TABLPJ v. ANALYTICAL CONTROL Run and Generation
S
20-200° C. 2 0 ~ ~ ~ ~ ! ! ~ 4 2 ' ' 200-270° C. (68-392' F . ) F.) (392-518' F.) Vol. % Sp. Gr. Vol. $'% Vol. % SP. Gr.
No.
Gr.5 a8 geceived
66-3 66-5 67-7 67-8
0.927 0.919 0.918 0.916
27.8 28.2 29.4 30.1
0.813 0.809 0.809 0.821
11.2 10.0 10.1 9.6
25.8 26.8 26.0 28.1
63-4 64-5 64-6 64-8
0.915 0.914 0.914 0.915
30.5 31.5 29.6 28.6
0.815 0.815 0.813
9 6 12.1 12.1 12.4
27.2 33.0 29.0 30.5
60-8 61-9 61-11
0.910 0.914 0.905
31.6 29.3 32.0
0.812
0.812 0.801
11.7 14.6 13.5
30.2 30.3 33.0
69-5 70-8 70-9
0.927 0.922 0.922
28.0
0.825 0.823 0.813
13.5 11.5 12.4
28.5 29.0 29.8
l0Pl
D.4TA
270-300" C. (518-572' F.) Vol. % Sp. Gr.'
300-330' C. (572-626' F.) vol. % Sp. Gr.
Over 3300 Vol. %
20-330' C., Sp. Gr.
c.,
Upper Freeport 0.945 0.942 0.938 0.940
17.2 17.9 17.4 18.1
0.969 0.969 0.963 0.966
17.2 21.7 18.3 14.5
0.988 0.993 0.9S6 0.987
12.0 5.4 8.9 9.2
0.918 0.921 0.914 0.911
16.7 12.1 17.5 14.0
0.965 0.966 0.963 0.963
17.2 17.0 14.0 15.0
0.982 0.985 0.981 0.980
8.4 6.4 9.9 11.9
0.915 0.912 0.911 0.910
15.8 19.2 17.0
0.964 0.963 0.959
13.9 15.6 15.0
0.977 0.976 0.972
8.5 5.6 3.0
0.906 0.914 0.904
18.5 17.5 18.9
0.969 0.969 0.970
17.5 17.0 16.9
0.985 0.984 0.991
7.5 8.5 7.1
0.924 0.922 0.922
Black Creek
0.810
0.946 0.942 0.939 0.941 Lower Sunnyside 0.942 0.945 0.939 Indiana No. 4
a
28.0 27.3
All specific gravity data taken a t 15.6' C. (60' F.).
0.950 0.947 0.947
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1.N D
USTRIAL A N D EN G I NEERIN G CHEMISTRY
Vol. 33, No. 8
TABLEVI. SPECIALOVERHEAD-OILANALYSES(PER CENTBY VOLUME) Boiling Range,
c.
Fraction Yoof total overhead Sp. gr. a t oil 15.6' C.
% in Fraction Tar acids Tar bases
Saturates
Refractive Index a t 20° C .
Saturates Rings per mol. of naphthenes
64.6 33.0 24.6 17.0 11.0
1.4250 1.4500 1.4553 1.4627 1.4690
1 1 1 1 1.5
71.4 48.0 36.0 24.6 20.0
1.4223 1.4468 1.4526 1.4586 1.4635
1 1 1.3
69.6 43.0 31.4 22.4 18.0
1.4252 1.4450
1 1
% in Neutral Oil Olefins
Aromatics
% of naphthenes
Upper Freeport, Runs 67-6, 67-7, and 67-8 20-188 188-207 207-235 235-270 270-300
26.9 4.9 10.3 14.7
19.1
0,802 0:9i2 0.947 0.966
5.2 20.0 16.5 11.5 7.0
2.8 6.3 3.6 2.0 1.5
8.0 8.0 6.0
4.2 4.0
27.4 59.0 69.4 78.8 85.0
61
100 100 100 100
Black Creek, Runs 64-6 and 64-7
0.961
8.0
2.0
Lower Sunnyside. Runs 61-9.61-10, and 61-11 1
1
51 97 100 100 100
Indiana No. 4, Runs 70-8, 70-9 and 70-10 20-188 188-207 207-235 235-270 270-300
23.0 7.2 11.5 16.8 18.2
0.798 0:940 0.952 0.965
6.5 40.2 30.5 21.0 14.0
3.0 3.5 2.5 3.0 1.5
8.4
7.0
6.0 5.0 5.4
22.0 50.0 62.6 72.6 76.6
....
1.4520 1.4580
... 1 1
59
91 ... 100
100
index and boiling point. The composition of the 20-188" C. fractions was therefore 35-40 per cent naphthenes, 29-36 saturated paraffins, 18-27 aromatics, and 7-10 olefins. The latter are mainly cyclic olefins, as indicated by the fact that the refractive index of the residual oil from successive extractions does not change appreciably with progressively increasing concentrations of sulfuric acid from 72 t o 84 per DISTRIBUTION OF LOW-BOILING TARACIDS TABLEVII. PERCENTAGE cent. Refractive indices of the satuUpper Black Indiana Lower Mary PittsIllinois rates in all fractions boiling above Freeport Creek No. 4 Sunnyside Lee burgh No. 6 McKay 188' C. indicate that they are pre19 20 16 26 26 Phenol 34 21 18 24 31 37 24 31 27 27 Cresols 27 dominantly naphthenic compounds. 44 56 53 47 47 Xylenols 42 48 55
per cent of the tar acids boiling below 235' C. is xylenols, 30 per cent cresols, and 20 per cent phenol. The principal constituent of all fractions from the overhead oils was neutral oil, whose composition varies greatly with the boiling point. The olefin content, as determined by ex-
Acknowledgment traction with 86 per cent sulfuric acid, decreases with molecular weight (boiling point used as index of molecular weight) until the 270-300' C. fraction, where a small increase occurs. The olefin content of neutral oils from the Mary Lee, Pittsburgh, Illinois No. 6, and McKay coals (6) showed a sharp increase in the 235-270' C. fraction. The operating temperature for these coals was 15-30' C. (59-86' F.) lower than that for the coal described in the present paper; for the later work 0.05 per cent iodoform plus 0.1 per cent stannous sulfide was used as catalyst, whereas 0.5 per cent molybdic acid plus 0.5 per cent stannous sulfide was used for the earlier work. It is possible that the iodine-containing catalyst saturates the high-boiling olefins more rapidly than the molybdic acid catalyst. Another possibility is that the higher operating and lower reflux temperatures of the later experiments result in retention of some of the higher boiling olefins in the recycle oil. I n general, the overhead oils discussed in the present paper contain appreciably more low-boiling material than those of the earlier paper (1). The aromatic content of the neutral-oil fractions of Table VI increases with molecular weight from 18-27 per cent in the 20-188' C. fraction to 73-85 per cent in the 270-300" C. fraction. Aromatic hydrocarbons predominate in all of the fractions boiling above 188" C., except the 188-207' C. fraction of the oil from Lower Sunnyside coal. The saturated hydrocarbons in the fractions boiling below 188" C. contained 50-60 per cent naphthenes, as estimated from the refractive
The authors wish to acknowledge the indispensable help of many Bureau of Mines workers, particularly those operating the experimental plant and its control laboratory, the instrument shop, and the coal analysis laboratories. Cordial cooperation in obtaining coal samples was given by the De Bardeleben Coal Corporation, Birmingham, Ala. ; the Columbia Steel Company, of Provo, Utah; Walter Bledsoe & Company, Terre Haute, Ind. ; and the Industrial Collieries Corporation, Bethlehem, Penna.
Literature Cited (1) Fieldner, A. C., a n d others, Bur. Mines, Tech. Paper 525 (1932). (2) I b i d . , 531 (1932). (3) I b i d . , 621 (1941). (4) Fisher, C. H., a n d other*, Fuel, 19, 132-8, 162-72 (1940). ( 5 ) H i r s t , L. L., a n d others, IXD.ENQ.CHEM.,31,869-77 (1939). (6) Ibid.. 32.864-71 (1940). (7) McArdle, E. H., a n d others, IND.ESG. CHIM.,Anal. E d . , 11, 248-50 (1939). ( 8 ) Storch, H. H., a n d Fieldner, A. C., Mech. ETZQ..61, 605-11 (1939). (9) St&h,H. H., a n d others, Bur. Mines, Tech. Paper 622 (1941). (10) Storch, H. H., a n d others, IND. EXG,CHEW., 29, 1377-80 (1937). (11) Thiessen, R., a n d Sprunk, G. C., B u r . Minos. Tech. Paper 573 (1937). PRESENTED before the Division of Gas and Fuel Chemistry at the 1Olst Meeting of the American Chemical Society, St. Louis, 310. Published by permission of the Director, U. S. Bureau of Mines.
