Liquid-Phase Hydrogenation of
Pittsburgh Seam Coal L. L. HIRST, C. 0. HAWK, G. C. SPRUNK, P. L. GOLDEN, I. I. PINKEL, R. L. BOYER, J. R. SCHAEFFER, R. H. KALLENBERGER, H. A. HAMILTON, AND H. H. STORCH
Central Experiment Station, U. S. Bureau of Mines, Pittsburgh, Penna.
Quantitative procedures for the hydrogenation assay of American coals have been developed. This work involved the perfection of mechanical equipment for continuous operation of the experimental plant and development of feasible quantitative tests. All work was done with Pittsburgh seam coal from the Bureau of Mines Experimental mine a t Bruceton, Penna. The assay work on this coal has been completed. Data are presented concerning the effect of varying temperature, contact time, agitation, and pressure. The assay comprises determination of the optimum conditions in liquid-phase hydrogenation for the maximum yield of a “middle” oil consistent with the complete regeneration of the vehicle used in making paste with the original coal. For Bruceton coal the optimum conditions are approximately 440” C., 200 to 300 atmospheres pressure,
A
2.75 hours of contact time, and circulation of about 100 cubic feet (measured a t 20’ C. and 760 mm. pressure) per hour of hydrogen. Under these conditions a yield of about 66 per cent of “middle” oil (containing 20 per cent boiling in the gasoline range and 80 per cent boiling below 330’ C.) and 20 to 25 per cent of hydrocarbon gases (methane to butane) is obtained in a single pass through the converter. The 9 to 14 per cent loss consists of 6 to 8 per cent of unreacted carbonaceous material (fusain and opaque attritus) and 3 to 6 per cent of oxygen, nitrogen, and sulfur hydrogenated to water, ammonia, and hydrogen sulfide. The “middle” oil contains 15 to 18 per cent of tar acids and 3 to 5 per cent of tar bases, and the remaining neutral oil contains 6 to 8 per cent olefins, 67 to 70 per cent aromatics, and 22 to 27 per cent saturated hydrocarbons.
DESCRIPTION of the Bureau of Mines experimental coal hydrogenation plant was published in 1937 ( 6 ) . Since that time a study has been made of the effect of varying temperature, time of contact, and agitation (hydrogen recirculation rate) on the hydrogenation of Pittsburgh seam coal from the Bureau of Mines Experimental mine a t Bruceton. Penna. Some changes have been made in the plant since the last published description ( 5 ) . The first section of €he present paper discusses these modifications. Later sections present data on Bruceton coal and a critical discussion.
Changes in Plant During the operation of the hydrogen plant, it was found that the carbon dioxide content of the finished gas increased. Thus, after the plant was operated for a few hours, as much as one per cent of carbon dioxide was found in the hydrogen, and
this could be reduced only by decreasing the output of the water-gas generator. (Figure 1 shows the flow diagram.) Simple experimentation demonstrated that this increase in carbon dioxide content of the hydrogen was due largely to insufficient regeneration of the tetramine solution. When larger plant quarters became available in September, 1937, the size of the tetramine regenerator kettle was increased from 24 inches in diameter and 12 inches in height to 36inches in diameter and 24 inches in height, its volume was thus increased three to four times. T h e l e n g t h of t h e r e g e n e r a t o r column was increased from 9 to 16 feet and that of the scrubbing column from 11 to 20 feet. Since these changes were made, the carbon dioxide c o n t e n t of t h e scrubbed hydrogen has not exceeded 0.1 per cent, regardless of the number of cons e c u t i v e h o u r s of operation. FIGURE1. FLOWDLAQRAM OF THE HYDROGBN PRODUCTION UNIT 869
VOL. 31, NO. 7
INDUSTRIAL AND ENGINEERING CHEMISTRY
870
converter makes it possible to discharge a distilled overhead oil and a Light oil and gas tarlike heavy oil slurry from the standI I pipe overflow, and to circulate hydrogen a t a much greater rate than would be possible without it. With no heat exchanger, so much volatile liquid distills out of the converter that the heavy oil slurry is too viscous to disand a t high charge even a t 100" circulation rates an external hydrogen preheater would be necessary in the absence of the heat-exchange coil. The aluminum coil, which was used in the first heat exchanger, failed, probably owing to a small excess of inlet pressure over converter pressure. There was little evidence of corrosion of the aluminum in the exchanger, although an iron clamp used in attaching it to the head was heavily sulfided. Subsequent exchangers have been made of approximately 45 feet of s/16inch 0. d. X '/rinch i. d., 18 per cent c h r o m e 8 per cent nickel alloy tubing, wound into eighteen layers of mixer Unreacted-coal pancake coils. These coils are wound catalyst from the inside out and spaced about F I G U R2.~ FLOWDIAGRAM OF THE HYDROGENATION SYSTEM 1 / 4 inch apart vertically; there are about four-and a half turns of tubing per pancake. The heat-exchange coil is slipped into a 22The tetramine solution used to absorb carbon dioxide was gage, 18 per cent c h r o m e 8 per cent nickel alloy can, open on found sufficiently corrosive to cause leaks to develop a t the the bottom end and closed on the top end, except for a l/sbutt-welded seams of the heat-exchange system. This inch pipe outlet which is attached to the top head of the consystem, made of l/S-inch black iron pipe welded inside of 1verter. Recently the bottom end of this exchanger, which inch black iron pipe, has been replaced by a similar exchanger made of seamless steel pipe of the same sizes. Gregory and Scharmann (9) report that oxygen in the hydrogen being scrubbed by 50 per cent triethanolamine was responsible for considerable corrosion observed in their equipment. HowU. S.S. thread -4 ever, the gas scrubbed in the authors' unit probably contains very little oxygen since the system is under positive pressure, and before reaching the scrubber all of the gases pass over a very active copper-cobalt catalyst which would cause the combination of hydrogen and oxygen to proceed rapidly. No oxygen could be introduced as dissolved gas in the spray tower because no tap water is used in this tower, the circulated water being cooled by passage through finned copper tubes cooled by building-ventilation air. Wear on the rotors of the small liquid pumps that circulate the tetramine solutions has been excessive and is greatest in the pump that delivers the hot regenerated tetramine solution to the first heat exchanger. It is necessary to replace these pumps after a few hundred hours of operation. The fouling by carbon deposition of the nickel catalyst in A and B are the wearing the water-gas generator is very slow. Only once for every parts and are replaceable 75,000 cubic feet of hydrogen produced is it necessary to pass air through the generator to remove carbon. The water-gas shift catalyst (a copper-cobalt mixture) is as active now as when first put into service. The flow diagram for the hydrogenation system (Figure 2) shows the present arrangement of equipment. No changes have been made in the converters, although seizing or galling of the top end threads has occurred several times, after runs in which no heat exchanger was used in the converter; hence the top closure became hotter than usual. Dimensions in inches Inlet It is thought that use of a harder or softer alloy for constructing the retaining nut will relieve this trouble. FIGURE 3. DISCHARGE VALVEFOR SLUDGE, 2 X 2 l / ~X 6l/2 The use of a heat-exchange coil in the top section of the INCHES IN SIZEAND MADEOF 18-8 STAINLESS STEEL
r
I
Circulated gas
,
,
,
I
c.,
5
77
'
JULY, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
OF COXPONENTS IN FIGURE 4. TYPESOF COALAND PERCENTAGE BUREAUOF MINESEXPERIMENTAL MINE
Percent TEE PITTSBURGH BED,
871
terminates near the bottom of the converter, has been protected with a vertical stainless-steel ball check valve. The hydrogen inlet line a t the top of the converter has also been protected with a horizontal stainless ball check valve. Paste pumping in general has been smooth and regular. A new and more sturdily constructed high-pressure paste pump has been installed. It is somewhat better adapted to pumping viscous pastes of the type that are characteristic of Bruceton coal, since it has a longer and less frequent stroke. Adjustment of delivery is made as in the other p u m p t h a t is, by changing the length of the stroke. The introduction of a rotary pump to agitate the coal-oil paste by recirculation and to feed the paste under positive pressure to the high-pressure paste pump made t h e p a s t e - p u m p i n g operation much smoother and eliminated frequent loss of prime by the high-pressure pump. Originally the auxiliary rotary paste pump was fed by a suction pipe which dipped into the paste feed tank on the platform of a sensitive scale and later by a similar suction pipe which was steam-jacketed. The delivery of the rotary pump became erratic as the feed tank emptied, so that a new feed tank with steam-jacketed sides and conical bottom was built. The pump was then fed from the conical bottom, first by a a/d-inch bore, woven-metal hose and later by a 6/g-inch bore, Neoprene tube. Weighings were extremely erratic when the metal hose was used, but with the Neoprene tubing weights of the paste and container are reproducible to 0.01 pound; and additions of 150 pounds of paste to the feed tank, as determined by the paste scale, check to the closest 0.10 pound when compared with the weight determined by another scale. The agitation produced in the paste feed tank by the return of the excess paste pumped by the inlet of the high-pressure paste pump is all that is necessary, since it is possible t o pump 150 to 200 pounds of paste from the feed tank with no additional stirring. H e a v y oil n o w d i s c h a r g e s through the valve shown in Figure 3. The replaceable cylinder and plunger generally discharge the
872
INDUSTRIAL AND ENGINEERING CHEMISTRY
product for about 24 hours before needing replacement. The small-bore tube coil which was used formerly is not satisfactory for the discharge of the viscous heavy oils that have been produced since a vehicle characteristic of Bruceton coal has been used in making the pastes. The needles of valves used in throttling gas discharges from the high-pressure system have been given a slimmer taper, resulting in much finer control over these discharges.
VOL. 31, NO. 7
10-17 inch layer of dull, hard, compact, semisplint to splint coal. I n three of the mines the dull coal formed the top of the bed, and in one mine (Edenborn) there was a second bright coal layer above the dull coal. I n the assay work on Bruceton coal a representative sample of the entire working face of the seam was used.
This sample was ground in a Raymond pulverizer to give 98 per cent passing a 200-mesh screen. Some experiments on the effect of particle size of coal have been reported by the Assay Work on Bruceton Coal British Fuel Research Laboratory ( I ) , but no such work has et been done in the Bureau of Mines Experimental plant. The Pittsburgh bed is probably the most extensive and Faste was made by adding 42-47 per cent by weight of this coal uniform coal bed in the United States. It extends west and to thinned and centrifuged heavy oil slurry in a steam-jacketed southwestward from Pittsburgh to the middle of West Virmixing tank in which the slurry was stirred by a high-speed mixer. In all cases the catalyst, which was added gradually with ginia for over 125 miles, where it is found in nine counties; the coal, was 0.5 per cent each of stannous sulfide and molybdic on the west it extends into Ohio, covering most of Belmont acid, based on the weight of the ground coal. Mixing continued and part of four other counties; in Pennsylvania i t occupies for 30 minutes to several hours before the paste was charged into a n area about 50 miles long and 50 miles broad embracing all the paste feed tank. After being charged to the feed tank, the paste was circulated of Greene and Washington and parts of five other counties; i t by a rotary pump through steam-jacketed pipes to the inlet of extends eastward into the Georges Creek Valley of Maryland, the high-pressure paste pump and then returned to the paste where i t is known locally as the Fourteen Foot or Big Vein. feed tank. These pastes were always so viscous that without use I n Pennsylvania the Pittsburgh bed is 4 to 16 feet thick; of a pressure control valve on the return line paste pressures at the high-pressure paste pump inlet were 20 to 30 pounds. After in Ohio it ranges from 2 to 6 feet; in Maryland i t averages circulation of paste became regular, it was pumped into the conabout 8 feet, although in one place in the Georges Creek Basin verter which had been heated to reaction temperature. Frei t attains a thickness of 22 feet; and in West Virginia i t ranges quent weighings and stroke adjustments were made until the defrom 7 to 9 feet. sired paste pumping rates were attained. During all runs the paste tank weight was determined to 0.01 pound every 15 The main bed is separated into an upper and lower portion minutes. by what is known as the bearing-in band, a bench about 4 The converter, which had a length of 8 feet and a bore of 3 inches thick, with thin 1/4-1/2 inch partings above and below. inches, was heated by four independent furnace sections whose A few other shale partings come in irregularly. temperatures were automatically controlled by thermocouples peened into the converter wall. Downward adjustment of these The column of coal received for petrographic analyses from control temperatures was sometimes necessary to maintain the the Bureau of Mines Experimental mine a t Bruceton, Penna., desired reaction temperatures (the hydrogenation is exothermic). was 63 inches thick. At this location the top bench is 36.3 The reaction temperature in the converter was determined by inches thick; the bearing-in bench, with accompanying shale No. 28 gage Chrome1 2, Cope1 thermocouples carried in a closed-end, '/s-inch bore X S/s-inch 0. d., 18 per cent chrome-8 binders, 3.5 inches thick; and the bottom bench, including per cent nickel alloy steel tube which extended the full length of two thin shaly streaks, 23.2 inches thick. the converter. The temperatures given by two couples, 33 and From the 63-inch column of coal, seventy-two thin sections 55 inches above the bottom of the converter, are considered to be were prepared. The sections were carefully examined with the reaction temperatures. Ordinarily the temperatures a t these points were not over 3" C. apart. A couple placed 12 respect to their nature, composition, and structure, and in inches above the bottom of the converter was 20" to 150" C. each the relative percentage of anthraxylon, translucent atlower in temperature, depending on the rates of paste pumping tritus, opaque attritus, and fusain were determined; the perand gas circulation. centages are shown graphically in Figure 4. Heavy oil slurry was discharged intermittently from the converter through a 1/2-inch diameter standpipe which was open It is of interest to note whether the petrography of the coal at the top end and extended 66 inches above the bottom of the from the Experimental mine a t Bruceton is representative of At a paste pumping rate of 7.5 pounds of paste per converter. the Pittsburgh bed from other localities. Table I gives the hour and 15-minute discharge intervals, the liquid level in the average petrographic composition of Pittsburgh seam coal converter would change 8 inches or less. Both light and heavy oils were discharged first into receivers a t gasholder pressure, from four mines located in four different counties. where dissolved gases were separated, then to 5-gallon pails on a scale. Weighings to 0.01 pound were made following each discharge. T A B LI.~ PETROGRAPHIC COMPOSITION OF THE PITTSBURGH Dry gas meters were used to determine the volumes of ( a ) BEDAT FOUR LOCATIONS hydrogen added from storage to maintain the gas holder at conPittsburgh stant volume, ( b ) gas purged from the converter, ( c ) gas returned Edenborn Terminal Consolidation Experimental from the converter to the gas holder, and ( d ) gas dissolved in the Mine, Mine No. 9 Mine, No. 63 Mine, liquids discharged from the converter. The reported figure for Fayette Alle he& Washington Marion Co., Components co., senna. co., Penna. W. Va. Co., Penna. circulated gas is the sum of the purge gzs and the as returned to the gasholder from the converter. The volume o f hydrogen abAnthraxylon 63 65 50 50 Translucent sorbed is equal to the volume of hydrogen added to the holder 22 24 40 44 attritus less the volume of hydrogen in the purged and dissolved gases as Opaque attritus 12 7 7 2 determined from their volumes and analyses. An average 6Fusain 3 4 3 4 cubic-foot sample of purged gas was collected in a small gasholder during the test period, which generally lasted 6 hours, and all dissolved gas was collected in a larger holder. At the end of the There is close agreement between the petrography of the period these collected gases were sampled for Orsat analysis and Experimental mine and the Pittsburgh Terminal No. 9 mine, gas density determinations by means of gas balloons. The discharged overhead oil, which contained the water and also between the Consolidation No 63 mine and the pumped into the converter and the water, ammonia, and sulfide Edenborn mine coals. The Experimentat mine coal has the resulting from hydrogenation, was centrifuged and decanted to highest content of opaque attritus and the Edenborn mine separate it into water and oil layers whose weights were determined. The heavy oil slurry was heated and sam led, then dicoal the least. luted with 30 per cent by weight of the light oil an8 centrifuged. The types of coal are the same in the four mines; that is, The centrifuged oil was used to make paste as outlined above. in each instance a bottom layer of bright coal extends from The solids obtained in centrifuging, which generally contained the bottom bench through the bearing-in bench to 15-22 about 40 per cent by weight of oil soluble in benzene, were not inches above the bearing-in bench. Above this point occurs a used in subsequent hydr
JULY, 1939
IKDUSTRIAL AND ENGINEERING CHEMISTRY
813
OF OIL YIELD, GAS LOSS, .4ND RATIOO F OVERHEAD TO HEAVY OILS ON TEMPERATABLE 11. DERIVEDDATASHOWING DEPEKDENCE TURE, CONTACT TIME,PRESSURE, AND HYDROGEN RECIRCWLATIOK RATE
Run No. 16-1 16-2 16-3 16-4 19-2 19-3 19-6a 19-8 19-9 4 19-10 19-1 16-1 16-5 17-2 19-4 17-1 19-3 19-6 19-Sa 13
11
16-3
Temp.,
' C.
420 433 447 459 440 440 44 1 440 441 44 5 440 440 420 420 440 440 440 440 440 439 450 448 447
Paste Pumping Rate, Lb./Hr. 7.4 7.1 7.5 7.4 3.8 7.3 7.1 7.3 8.4 8.5 9.2 10.0 7.4 5.0 7.2 7.1 7.4 7.3 7.4 6.9 7.3
7.0
7.5
Hydrogen Recirculation Rate, Cu. Ft./Hr.
Reflux
272 293 265 237
18-8 coil 18-8 coil 18-8 coil 18-8 coil
229 228 243 238 228 250 259 243 272 110
Contact Time 18-8 coil 1.26 18-8 coil 0.58 0.55 18-8 coil 0.46 18-8 coil 0.35 18-8 coil 0.78 None 0.32 18-8 coil 18-8 coil 0.39 0.41 18-8 coil 0.47 18-8 coil
0 50 80 228 270 416 80 180 265
Hydrogen Recirculation Rate 18-8 coil 0.37 >4000 0.25 282 18-8 coil 0.54 18-8 coil >4000 18-8 coil 0.58 787 0.51 1150 18-8 coil 0.56 1830 18-8 coil 1.38 None 1.68 None .. 18-8 coil 0.90
Ratio of Overhead t o Heavy Oil Temperature 0.41 0.62 0.90 1.72
Viscosity of Heavy Oil Slurry, Centistokes
.. .. ..
Per Cent on Ash- and Moisture-Free Coal H2 C -
Oil yield
'
+
Gas loss
-
Tons of Estd. Yieldb Overhead of Gasoline Oi1/100 in Tons/100 Tons Tons of Coal of Coal Chargeda Charged
71.0 66.2 60.2 52.5
9.9 19.6 32.7 36.9
67.5 65.2 61.3 52.4
54.0 52.1 49.3 42.0
62.7 68.8 67.7 71.8 72.0 78.0 73.3 64.5 71 .O 65.8
29.5 21.9 20.5 18.8 16.8 16.7 15.3 13.9 9.9 17.3
66.1 68.1 66.6 70.7 71.6 76.3 71.8 63.3 67.5 64.3
52.9 54.5 53.3 56.5 57.3 61.1 57.5 50.7 54.0 51.4
..
66.5 62.0 62.6 68.8 65.7 71.9 67.5 65.3 60.3
11.5 23.5 14.6 21.9 21.3 19.6 25.5 25.5 32.7
66.2 62.3 62.0 68.1 65.7 71.9 66.5 64.1 61.3
53.0 49.7 49.6 54.5 52.6 57.5 53.2 51.2 49.3
560 1320 787 1808
70.5 71.8 68.8 67.7
21.6 18.8 21.9 20.5
70.1 70.7 68.1 66.6
56 1 56.5 54.5 53.3
.. 287 787 1808 1320 1190 1660 1350
..
..
..
Pressure 19-7C 19-8 19-3 19-6a a
b c
44 1 440 440 44 1
7.3 7.3 7.3 7.1
218 238 228 243
18-8 coil 18-8 coil 18-8 coil 18-8 coil
0.44 0.46 0.58 0.55
Coal containing 1.6 per cent moisture and 6.3 per cent ash. Calculation based on assumption of 80 per cent yield in hydrogenation cracking of overhead 011. Run at 4500 pounds per square inch hydrogen pressure.
The water layer separated from the overhead oil was analyzed for ammonia, carbon dioxide, chlorides, and sulfur after filtration to remove small amounts of solids and oil. The oil layer was dried by contact with anhydrous sodium sulfate for 24 hours and then filtered and distilled, 200 cc. of oil being weighed into a 300-cc. still fitted with an indented glass column 6 inches long. Distillation was stopped at 330" C.; specific gravities of the cuts were taken with small hydrometers at room temperature and corrected to 15.6" C. with the aid of the National Bureau of Standards oil table (4). Tar acids, tar bases, olefins, and aromatics were determined in the combined distillate. The olefins were determined simply by extraction with 85 per cent sulfuric acid (shaking with three volumes of acid for 5 minutes). The specific gravity of the heavy oils, which were very viscous or firm hard pitches a t room temperature, depending upon whether or not they had been Centrifuged, was determined a t 25' C. by means of a Hubbard bottle and the A. S. T. M. method. Insoluble material in these oils was determined for the early runs by first stirring about 40 grams of heavy oil with 120 cc. of acetone in a centrifuge bottle, then centrifuging and decanting the acetone solution; the stirring with acetone was re eated six times before the residue was dried at 110" C . for 24Rours and weighed. After weighing, the residue was extracted 3 days with benzene in a Soxhlet or Wiley extractor, dried, and again weighed. For the more recent runs, after about 120 cc. of tetrahydronaphthalene at 100" C. had been worked into about 40 grams of heavy oil in a centrifuge bottle, the mixture was centrifuged and decanted. This was generally followed by two additional hot tetrahydronaphthalene washes and one benzene wash at room temperature. The residue from this treatment was then extracted as above with benzene. Insoluble content, as determined by this method, was lower than that determined by the acetone method. The effect of solvent and other variables on free carbon determination has been described (6).
Dependence of Yields on Operating Conditions I n order to make the results of the assay work on Bruceton coal more readily available, the presentation of the operating and analytical data is postponed until a discussion is given of the effects of temperature, contact time, and hydrogen recirculation rate on the yields of oil and gas. Table I1 summarizes these data.
The data on the effect of varying temperature show that the yields of benzene-soluble material decrease and the gas losses increase with increasing temperatures. The limiting low temperature is determined by the time of contact desired and the viscosity of the heavy oil slurry. From a practical standpoint the heavy oil slurry of experiment 16-1 was as thick as could be conveniently discharged a t 100" C.; hence if a lower temperature were desired, a longer contact time would be essential. It should also be noted that the ratio of overhead oil t o heavy oil increases with increasing temperature. I n operation of the experimental plant for assay purposes it seemed desirable to adjust the ratio of overhead to heavy oil so that the amount of the latter would exactly equal the weight of vehicle mixed with the original coal. With a mixture of about 40 per cent coal (ash- and moisture-free) and 56 per cent vehicle, the ratio of overhead to heavy oil for a 70 per cent oil yield should be 1 t o 2. I n addition to varying this ratio by changing the average reaction temperature, a very exact control may be exercised by regulating the amount of heat put into the top section of the converter, which would in turn control the amount of refluxing. I n the later runs with Bruceton coal it was found essential to add to the heavy oil slurry about 30 per cent of its weight of overhead oil. This was necessary to make u p for handling and sampling losses and to thin the tarry heavy oil slurry so as to make easier the centrifuging and subsequent pumping of the paste made with the centrifuged oil. I n a large plant the handling losses would be practically eliminated and the sampling loss would be negligible. It is therefore probable that the addition of 10-15 per cent of middle oil to the heavy oil slurry will suffice to regenerate the pasting oil. This addition changes the overhead to heavy oil ratio necessary for complete regeneration of pasting oil from 0.5 to about 0.85. The effect of increasing the contact time from 2 t o 4 hours
INDUSTRIAL AND ENGINEERING CHEMISTRY
874
VOL. 31, NO. 7
TABLE111. OPERATING DATA Materials Discharged from Converter
Run No.
Temp.5
C. 445 435 463 448 448 450 440 420
4a 6b
8 11 12 13 14 16-1 16-2 16-3 16-4 16-5 17-1 17-2 19-lb 19-2b 19-3b 19-46 19-6b 19-55 19-65 19-70 19-8 19-9 19-10
Hydrogen e Reairoulation Rate Cu. f t . / h r .
Paste Pymping Rate
Lb./hr. 8.5 5.2 8.0 7.0 8.4 7.3 5.6 7.4 7.1 7.5
433
250 200 290 180 370 80 160 272 293 265 237 110 80 0 229 228 243 50 270 416 243 218 238 228 259
7.4
5.0 7.4 7.2 10.0 3.8 7.3
440
440 --_
7.1
440 440 439 441 441 440 441 440
7.3 6.9
7.1
7.3 7.3 8.4 9.2
Materials Pumped into Converter A
Coal
Oil
Water
Lb. 46.5 68.8 107.3 93.9 56.0 165.5 86.4 20.6 18.1 20.9 10.3 9.8 20.5 20.1 21.0 5.6 18.5 21.5 18.1 15.3 15.6 17.7 18.4 17.6 19.2
Lb. 47.5 98.4 134.3 104.0 62.2 183.5 104.1 23.7 20.8 24.1 11.8 11.2 23.6 23.2 23.9 7.7 25.5 29.8 24.9 21.1 21.6 24.4 25.4 24.4 26.6
Lb. 0
0 5.0 6.0 3.3 17.0 0 2.1 1.7 1.8 0.9 1.0 2.0 1.1 2.3 1.8 3.2 3.9 3.0 2.8 2.6 3.2 5.1 4.1 4.2
c
-.
Heavy Oil Slurry c -
Hydrogen absorbed
Overhead oil
Water
Lb. 2.7 5.1 7.5 5.6 3.4 11.1 6.3 1.2 1.1 1.6 0.8 0.8 1.4 1.5 1.3 0.7 1.3 1.8 1.3 1.2 1.2 1.3 1.1 1.3 1.1
Lb. 36.3 60.8 108.2 97.0 55.1 152.5 62.5 9.8 11.2 15.7 10.0 5.2 11.6 9.0 10.0 5.8 12.8 8.0 11.4 10.4 10.3 10.2 10.9 8.8 8.9
Lb. 2.7 2.2 14.4 12.0 5.0 26.3 1.6 2.9 2.4 2.8 1.6 1.3 3.2 2.5 4.3 2.4 4.7 5.2 4.3 3.6 3.7 4.2 6.5 5.1 5.3
Centrifuged oil
Centrifuge remdues
Lb. 50.1 91.7 94.8 69.3 45.6 139.3 94.4 29.4 21.5 20.6 8.4 12.6 26.0 28.8 31.3 5.8 27.1 38.0 27.5 22.9 23.4 27.5 29.0 30.4 34.1
Lb. 16.2 7.8 6.8 17.3 10.9 3.5 3.0 2.5 1.8 3.0 3.5
Differenoe Meterials i n OutGas
Loss
Lb. 7 ..6 17.6 20.5 23.4 12.4 41.7 27.4 2.0 3.6 6.8 3.8 1.9 3.7 2.1 2.9 1.8 3.9 5.8 4.1 3.5 3.6 4.5 3.5 3.1 2.8
Reflux None AI coil A1 ooil None Nnne
None None
18-8 coil 18-8 ooil coil
18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 coil 18-8 18-8 0011 cojl 18-8 coil
a Average of second and third couple from bottom. b Samples not centrifuged.
-
Preasure
4500 pounds instead of 3200.
TABLEIV. AQUEOUSLAYERS SEPARATED FROM OVERHEAD OILS R u n No.
Sp. Gr.
Temp.
oc.
...
4 6 11 12 14 16-1 16-2 16-3 16-4 16-5 17-1 17-2
..
l:046 1.060 1.063 1.015 1.018 1.021 1.023 1.025 1.023 1.032
TABLEV.
25 25 27
_26 _ 26
26.5 26 26 23.5 24
COX
NHs
c -
C1 Grams per liter--
97.5 55.5 51.5 65.8 67.4 9.8 13.2 18.0 23.8 20.1 17.5 26.8
78.0 45.5 31.9 41.4 53.2 17.9 20.0 27.0 31.3 28.4 22.8 31.6
Centrifuged Heavy Oil
Run No.
Heavy Oil Slurry
45 60 8 11 12 13 14"
0.0 0 6.5 9.1 12.3 16.2 20.7
6.7 7.6
2617
16:3 16.3 15.9 11.6 12.0 13.0 13.0
25 :2 26.2 28.0 31.5 23.2 26.8 26.3
14a*
14b* 140* 14e* 16-1 16-2 16-3 16-4 16-5 17-1 17-2 5
3:2 5.7 8.2 11.8 10.2 12.0 11.6 17.6 15.0 18.2
BENZENE-INSOLUBLE MATERIAL IN HEAVY OILS (PERCENTBY WEIGHT)
Pasting Oil
~~
... ...
3.2 4.7 4.0 2.2 3.2 2.8 1.8 2.6 1.2 0.8
S
......
P * - ,
Organic
Ash
17:o 17.3 15.7 15.5 18.4 16.5 15.3
2.7" 0.85 2.1 5.0 3.1 6.3 9.95 7.4 6.6 5.9 5.6 3.7 4.1 3.9
14:o 16.6 14.7
3.2 4.0 4.2
16:Q 14.8 12.2 17.6
...
Centrifuge Residue
Organio
Ash
2i:1 31 .O 31.9 23.4
32:9 35.0 30.9 38.2
.. .. .. ..
.. .. 1
.
..
3i:5 29.8 27.4
30:l 33.4 31.9
3010
36:6
..
..
Not centrifuged. = 1 centrifuge pass, b = 2, o = 3, e = 5.
*a
(decreasing the paste pumping rate from 7.5 to 3.8 pounds per hour) is decreased oil yields and increased gas losses. For contact times of less than about 1.6 hours (9.2 pounds of paste per hour) a t 440" C., this trend reverses itself so that shorter contact times result in lower oil yields, although the gas losses are still decreasing. The exact location of the maximum yield cannot be stated with accuracy, but there can be no question of its existence.
No exact specifications can be given as to optimum temperature and contact time. For example, there is a fairly wide range of temperature in which the contact time may be adjusted so as to give the same yields and the same viscosity of heavy oil slurry. This temperature range for Bruceton coal is approximately 420 O to 440 O C. ; the corresponding contacttime range is 2.75 to 1.75 hours. At temperatures higher than 440" C. it is probable that a hjgher gas loss and lower oil yield would persist, even a t the limiting contact time for obtaining a sufficiently fluid heavy oil slurry. The data presented in this paper, however, are insufficient to justify any conclusive statement concerning the yields above 440" C. The data on the effect of varying hydrogen recirculation rates given in Table X are inconclusive. The effect, if any, must be small and within the limits of reproducibility of the runs. A similar conclusion has been reached by the British Fuel Research Laboratory (1). However, the results recently published by Morgan and Veryard (3) for hydrogenation under conditions such t h a t turbulent flow of the reactants existed, show that the reaction rate is markedly increased by turbulence. If the data of runs 17-1 and 17-2 are omitted, the viscosity data in Table X would then indicate that more viscous heavy oils are obtained a t the higher hydrogen circulation rates. There is, however, nothing in the records that would justify omitting runs 17-1 and 17-2. The effect of changing the pressure from 3200 to 4500 pounds per square inch may be noted from an inspection of the results given for runs 19-7, 19-8, 19-3, and 19-6a. The effect on oil yield and gas loss, if any, was very small. An appreciably lower viscosity of heavy oil slurry was obtained in run 19-7 a t 4500 pounds pressure than in run 19-8 a t 3200 pounds pressure. The viscosity of the heavy oil slurry of run 19-3 a t 3200 pounds pressure was, within the limits of reproducibility, identical with that of run 19-7. Hence the data concerning the effect of pressure are inconclusive. Operating and Analytical Data Tables I11 to XI contain the operating and analytical data. After the results of run 14 were available, it was realized that
INDUSTRIAL AND ENGINEERING CHEMISTRY
JULY, 1939 :
TABLEVI.
BENZENE-INSOLUBLE MATERIALS IN PASTE AND HEAVYOIL SLURRY (PERCENTBY WEIGHT)
Run No.
19-1
Paste Heavy oil slurry
50.8 49.8 49.0 49.0 49.6 50.3 50.3 50.5 51.1 49.8 49.9
19-2 19-3
19-4 19-6 19-5a 19-6a 19-7 19-8 19-9
19-10
18.7 20.5 18.0 17.1 17.3 18.5 20.5 16.5 18.9 18.2 18.3
, OIL, TABLEVII. ULTIMATE ANALYSESOF OVERHEAD OILS, ANTHRACENE AND BRUCETON COAL
Run No.
..
4 6 8 11 12 13 16-1 16-2 16-3 16-4 16-5 17-1 17-2
.. ..
a
Sample Anthracene oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Overhead oil Bruoeton coala Ash- and moisture-free
%
%
%
%
o,8 0.7 0.8 0.8
1,6
88.3 88.9 87.7
6,4 8.0 7.9 8.8
2.7 2.7 2.6
o,6 0.3 0.3 0.1
87.4 86.3 86.6 86,9 86.8
8.6 9.4 9.2 9,0 9.2
1.0 0.8 0.9 0.9 l.o
3.0 3.4 3.2 3.05 3.0
0.01 0.1 0.1 o,05 0.1
86.4 87.2 87.7 77.6 84.2
9.3 9.3 9.3 5.3 5.6
0.9 0.9 0.8 1.6 1.7
3.3 2.5 2.1 7.6 6.8
0.1 0.1 0.1 1.6 1.7
:;
::t5
::
C,H 14.2 11.0 11.1 10.0
t::
::g5
10.2
i:Qt 9.30 9.37 9.43
...
15.0
As received, containing 1.6 per cent moisture and 6.3 per cent ash.
TABLEVIII. RunNo. 4=
' 6 8 11 12 13 14a 14a* 14b* 14c* 14e*a 16-1 16-20 16-30 16-4a 16-1 16-2 16-3 16-5 17-1 17-2 0
%
ULTIMATE ANALYSESOF HEAVYOILS
Sg. Gr.
%C
%H
%N
%0
%S
% Ash
1.057
87.0 89.0 87.3 85.4 87.1 84.2 81.1 84.2 84.3 85.0 85.3 84.5 83.6 83.6 80.8 86.7 86.4 87.3 87.2 86.3 86.2
6.7 6.9 6.7 6.2 6.5 6.2 5.7 6.0 6.0 6.0 6.1 6.8 6.4 6.5 5.3 7.0 6.7 6.7 7.0 6.7 6.6
1.0 1.3 1.3 1.4 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.3 1.2 1.3 1.3 1.3 1.3 1.2
2.2 1.6 1.4 1.4 1.7 1.5 1.1 0.5 1.2 1.3 1.2 1.8 1.6 1.1 0.7 1.8 1.6 1.4 1.7 1.8 1.8
0.4 0.4 0.4 0.6 0.4
2.7 0.8 2.1 5.0 3.1 6.3 9.9 7.4 6.6 5.9 5.6 5.2 6.6 6.9 11.0 3.0 3.6 3.0 2.5 3.5 3.8
1:iOo 1.193 1.175 1.205 1.268 1.246 1.229 1.224 1,220 1.189 1.217 1,190 1,309 1.159 1.141 1.164 1,150 1.116 1.173
Not centrifuged. = 1 pass through centrifuge, b = 2 passes, c
*a
=
0.6
1.0 0.7 0.7 0.6 0.6 0.5 0.6 0.7 0.9 0.3 0.4 0.3 0.3 0.4 0.4
C/H 13.0 12.9 13.0 13.8 13.4 13.6 14.2 14.0 14.1 14.2 14.0 12.4 13.1 12.9 15.2 12.4 12.9 13.0 12.5 12.9 13.1
875
the insoluble matter in the centrifuged heavy oil was steadily increasing with the number of runs. This is readily seen by inspection of the fourth column of Table V, runs 8 to 13, inclusive. I n the same column are given the benzene insolubles for the heavy oil from run 14, centrifuged one, two, three, and five times. The content of benzene insolubles did not decrease appreciably after the third pass through the centrifuge. I n all runs subsequent to run 13 the heavy oil was passed through the centrifuge five times. It would have simplified the bookkeeping if it had been convenient to remove all of the insoluble material from the heavy oils. It was found, however, that even after dilution of a heavy oil with twice its volume of overhead oil, subsequent centrifuging removed only about two thirds of the benzene-insoluble materials. Although some dilution was needed to lower the viscosity of the heavy oil so that it pumped more readily, no excessive dilution was practiced. Tables V and V I show that the benzene-insoluble content reached a more or less steady amount. Complete removal of benzeneinsoluble material would therefore have rejected a liquefiable portion of the coal. The data in Table V are for the undiluted heavy oils, whereas the analyses in Table VI11 for runs 16 and 17 are for heavy oils diluted with 10 to 20 per cent of overhead oil. The dilution factor in each case can be calculated from the ratio of the ash percentages in Tables V and VIII. The analytical data in Tables IV t o X are considerably more detailed than are necessary for the assay of a coal for its hydrogenation characteristics. However, since Bruceton coal is to be used as a standard coal, it was considered de-
3, e = 5 passes.
TABLEIX. ANALYTICAL DATAON OVERHEADOIL (PERCENTBY VOLUME) Run No. 4 6 8 11 ~~
12 13 14 16-1 16-2 16-3 16-4 16-5
17-1 17-2 a
Sp. Gr.5 as Received 1.013 1.028 0.982 1.014 1.010 0.998 0.966 0.967 0.975 0.968 0.974 0.971 0.973 0.967
--20-200° Per oent 18.5 8.0 15.0 16.0 16.5 19.8 28.5 22.3 20.3 22.5 24.5 22.0 24.0 27.8
C.Sp. gr.a 0.880
0:sio 0.888 0.883 0.873 0.892 0.883 0.883 0.866 0.878 0,882 0.887 0.886
-200-270° Per cant 45.0 47.7 41.3 28.0 31.3 30.8 40.8 45.0 37.5 33.8 36.0 39.5 37.0 37.5
'2.Sp. gr.a 0.993 1.007 0.982 0.979 0,980 0.977 0.973 0.972 0.973 0.970 0.973 0.974 0.971 0.969
-270-300° Per cent 16.5 18.7 17.1 16.5 13.8 13.5 16.0 16.0 18.2 16.0 15.3 16.0 16.3 13.5
C.Sp. gr.a 1.054 1.054 1.024 1.025 1.014 1.014 1.002 0.998 0.999 0.998 1.004 1.005 1.010 0.999
-300-330° Per cent 10.0 18.6 15.5 14.0 15.0 12.8 11.5 12.0 14.5 14.7 11.5 12.5 10.0 9.7
C.-
Sp. gr."
Over 330 C Per Cent
.
At 15.6' C.
TABLEX. ANALYTICAL DATAON OVERHEADOILS DISTILLING BELOW 330' C. sirable to obtain a detailed balance of all elements. For this -7 of Total Oil- Sp. Gr. of of Neutral OilAroNeutral 'far Tar purpose the data in Tables IV to X are necessary. Olefins matics Saturates Oil acids bases Run No. The carbon-hydrogen ratios in Table VI1 for the overhead 4 9.2 4.2 0.990 1.019 8.1 5.0 6 oils show a progressive decrease from runs 4 to 17. This 0.975 12.0 4.7 8 decrease probably is due largely to the elimination of the 0.971 11 11.9 3.8 12 14.3 4.0 0.967 anthracene oil from the pasting fluid by the generation of a 0.954 14.2 3.5 13 0.947 14 14.9 3.5 vehicle characteristic of Bruceton coal. The decrease in 0.947 16-1 16.9 4.8 carbon-hydrogen ratio is somewhat erratic, owing to variations 0.952 16-2 17.4 5.0 0.938 16-3 16.8 5.0 in temperature, contact time, etc., from one run to the next. 0.942 16-4 15.8 5.0 0.947 16-5 16.9 4.6 Analogous progressive changes in the overhead oils are in0.942 17-1 17.5 3.5 dicated in Tables IX and X. Table IX shows an increase in 17-2 0.935 17.8 3.3 the 20" to 200" C. fraction from runs 4 to 16 and a correspond7%
INDUSTRIAL AND ENGINEERING CHEMISTRY
876
VOL. 31, NO. 7
hydrocarbons in the purge gas was about 30 (ethane = 30) TABLEXI. ANALYTICALDATAFOR Gas-Loss CALCULATIONSand in the dissolved gas about 42 (propane = 46). Probably, -Gas Analysis, % by Vo1.Gas therefore, the purge-gas hydrocarbon was a mixture of HydroDensities 4 v . Mol. methane, ethane, and propane, and that of the dissolved gas (Air = Weight of Volume, carRun S o . Cu. Ft. Hz bons 0 2 Nz 1) Hydrocarbons a mixture of methane, ethane, propane, and butane. Olefins Purge Gases were present in only minor amounts. 16-2 91.3 7.3 0.2 1.2 0.1673 37 1.1 7.5 16-3 91.5 0.3 .. 16-5 17-1 17-2 ~. 19-1 19-2 19-3 19-4 19-6 19-59 19-6-4 19-7. 19-8 19-9 19-10 ~~
16-2
16-3
16-5 17-1 17-2 19-1 19-2 19-3 19-4 19-6 19-5A 19-6A 19-7 19-8 19-9 19-10
394 435 445 388 370 37.4 39.6 21.7 40.0 42.4 36.6 20.0 37.6 51.0 37.8 35.0 34.0
92.5 93.4 92.8 89.2 93.6 90.9 86.8 91.8 89.3 91.3 92.1 91.8 92.5 92 0
5.8 5.3 5.3 8.0 5.7 8.1 10.8 7.3 6.8 6.8 6.6 7.0 6.9 7.0
83.9 76.7 80.8 79.1 80.6 78.8 80.6 74.9 73.2
Disf solved Gases 14.6 0 . 3 1.2 22.5 0.4 0.4 0.3 17.7 1.2 19.0 0.6 1.3 18.2 0 . 2 1.0 20.4 0.3 0.5 18.7 0 . 3 0.4 24.1 0.3 0.7 25.9 0 . 3 0.6
,
0.2 0.4 0.0 0.8 0.2 0.5 0.8 0.4 0.5
0.3 0.3 0.4 0.2
1.5 0.9 1.9 2.0 0.5 0.5 1.6 0.5 3.4 1.2 1.0 0.9 0.2 0.8
Discussion of Yields
23 24 26 31 32 32 28 33 31 31 29 29 30 29
0.2942 0.3675 0.3266 0.3257 0,3400 0.3570 0.3360 0.4170 0.4130 0.3480 0,3390
The yield of benzene-soluble materials and the gas losses are presented in Table XII. Bruceton coal contains the following petrographic constituents, which give the accompanying hydrogenation residues : Constituent Anthraxylon Translucent attritus Opaque attritus Fusain
51 40 42 39 43 42 42 43 40
% of Bruceton Coal % ' Organic Insol. Residue (Detd. by Petrograph~c (from Hydrogenation Tests in Small Autoclave) Examination) 63 1 22 1 12 25 3 91
From these figures we obtain 6.5 per cent of the ash- and moisture-free coal as the nonliquefiable fraction. The loss of oxygen, nitrogen, and sulfur by Bruceton coal upon hydro.. .. . . . ... genation, as practiced in runs 4 to 19, is between 2 and 6.5 . . ... ... .. per cent of the coal. The average percentage of hydrogen 22 .' 1 0 . 3 74:9 1.7 .... 18.5 0,3300 ki 0.3 1.0 49.0 80.2 absorbed in these runs is about 7. Hence the expected yields 19.2 0.3500 43.0 0.3 1.7 42 78.8 0,3310 19.7 0.4 0.0 as per cent of coal (ash- and moisture-free) plus hydrogen 34.0 40 79.9 1 7 . 7 0.4 0.7 0.3143 52.0 40 81.2 absorbed should be between 88 and 92 per cent. The only runs in which the benzene-soluble materials plus gas losses exceed the 92 per cent limit by more than about 1 per cent are 4, 12, and 14, the worst of which is run 12 with a total of ing decrease in the specific gravity of the overhead oils. Table 101 per cent. X shows a fairly steady increase in content of tar acid from A further evaluation of the accuracy of the mass balances run 4 to run 17 and a similar increase in the percentage of may be obtained by comparing the two sets of gas yield data saturated hydrocarbons in the neutral oil. All of these given in Table XII. The data in column IV were calculated changes probably are connected with the elimination of the from the gas volumes and analyses given in Table XI. The anthracene oil originally employed as pasting oil. data in column I11 were calculated from the mass balance of Table X I contains data on gas analyses and densities for Table I11 for the difference between the weight of materials runs 16, 17, and 19. The last column of Table XI is of some in and out of the converter. The agreement in nine cases interest. It shows that the average molecular weight of the (16-2, 17-2, 19-1, 19-2, 19-3, 19-6, 19-8, 19-9, and 19-10) is within 3 per cent of the'coal plus hydrogen absorbed, and in six cases (16-5, 17-1, 19-4, TABLEXII. DERIVED DATAON BENZENE-SOLUBLE OIL YIELDS AND GAS 19-sa, 19-6a, and 19-7) i t is within 8 per cent. LOSSESAS P E R CENT OF ASH- AND MOISTURE-FREE COAL P L U S HYDROGEN The average difference between the two sets of ABSORBED figures is 3.3 per cent. Ash1
Run No. 4 6 8 11 12 13 14 16-1 16-2 16-3 16-4 16-5 17-1 17-2 19-1 19-2 19-3 19-4 19-6 19-Sa 19-6a 19-7 19-8 19-9 19-10 0
b d e
and MoistureFree Coal Hz, Lb. 45.5 68.4 106.3 92.0 55.0 163.6 85.8 20.2 17.8 20.8 10.3 9.8 20.3 20.0 20.6 5.9
+
18.3
21.6 18.1 15.3 15.6 17.6 18.1 17.5 18.8
SolidNet Oil SolidFree % Oil Yields Free Heavy ProVehicle, Oil, duced,aI__h__ Ib IIC Lb. Lb. Lb. 47.5 46.7 35.5 78 0 61.4 98.4 79.6 42.0 66.6 ,. 125.7 88.1 70.6 60.1 94.6 57.7 653 ,. 43.1 78.4 52.7 40.7 153.4 1 1 0 . 8 109.9 67.5 67.3 78.0 57.7 82.8 68.8 73:2 23.9 13.9 19.8 66.3 66 1 18.0 17.4 11.8 62.0 58.3 20.3 12.9 17.5 5 . 4 52.5 10.4 5.8 9.9 11.0 6.3 64:3 67.2 20.5 21.6 12.7 62.6 66.5 20.2 24.5 13.3 . . 64:5 22.1 25.4 13.3 6 7 4.6 62.7 3.7 24.2 . . 68.8 22.2 12.6 26.1 ,. 62.0 31.5 13.4 22.2 22.7 65.7 11.9 71.9 18.1 18.7 11.0 . . 67.7 18.5 18.6 10.4 70.5 20.8 23.0 12.4 . . 71.8 21.4 23.5 13.0 21.1 72.0 24.9 12.6 22.9 13.8 73.3 27.8
Overhead oil plus Calculation based Calculation based Calculation based Calculation based
....
.. ..
..
..
.. ..
.. .*..
% Gas Yields IIId IVe 16.7 25.7 19.3 25.5 22.6 25.5 32.0 9.9 20.2 32.7 36.9 19.4 18.2 10.5 14.1 30.5 21.3 26.9 22.7 22.9 22.4 25.5 19.3 17.7 14.9
.. .. ,. .. ..
.. .. 1i:9 .. 15:l 11.0 12.5 13.7 28.5 22.6 20.2 19.8 16.4 18.6 17.7 18.3 16.0 15.6
Ratio Overhead to Heavy Oil 0.78 0.76 1.23 1.68 1.35 1.38 0.80 0.41 0.62 0.90 1.72 0.47 0.54 0.37 0.39 1.26 0.58 0.25 0.51 0.56 0.55 0.44 0.46 0.35 0.32
heavy oil minus pasting oil (vehicle) equals net oil produced. on benzene-insoluble data for centrifuged oil nnd centrifuge residue. on benzene-insoluble data for heavy oil slurry (not centrifuged). on mass balance. on gas-volume measurements and gas analyses.
Mass Balances A mass balance for oxygen input and output is set up in Table XIII. This balance shows discrepancies up to 40 per cent. Most of these are probably in the oxygen determinations (by difference) themselves. There are several points of interest in Table XI11 : 1. The percentage of the total oxygen a pearing as water out6ut increases regularly wit{ the temperature (runs 16-1, 16-2, 16-3, and 16-4). 2. The ratios of the oxygen contents of the overhead and heavy oils are roughly parallel to the mass ratios of these products. 3. The percentage of the total oxygen appearing as carbon dioxide shows some interesting variations. It is about 2 t o 3 per cent when the reflux coil is employed and about 6 to 7 per cent when no refluxing occurs. The reflux coil was not functioning in experiments 4, 11, 12, and 13.
Points 1 and 2 might easily have been predicted, but point 3 apparently is due to some factor that has not yet been given much consideration. This factor may be the equilibrium in
INDUSTRIAL AND ENGINEERING CHEMISTRY
JULY, 1939
IP; PRODUCTS TABLEXIII. OXYGENDISTRIBUTION
-Pounds R u n No. 4 6 8 11 12 13 14 16-1 16-2 16-3 16-4 16-5 17-1 17-2
Coal 3.5 5.3 8.1 7.1 4.2 12.5 6.6 1.6 1.4 1.6 0.8 0.7 1.6 1.5
Vehicle 0.8 1.6 1.8 1.5 0.8 2.7 1.6 0.3 0.3 0.3 0.2 0.2 0.3 0.3
of Oxygen in:Total Total outBalinput put anoe 4.3 4.8 +0.5 6.9 5.2 -1.7 9.9 12.8 +2.9 8.6 9.1 4-0.5 5.0 4.2 -0.8 15.2 16.0 4-0.8 8.2 4.9 -3.3 1.65 -0.25 1.9 1.7 1 . 3 3 -0.37 1.9 1 . 7 5 -0.15 1.0 1.01 + O . O l 0 . 7 8 -0.12 0.9 1 . 9 5 4-0.05 1.9 1.8 2.06 +0.26
-%
of Oxygen outputOverhead Heavy oil Hz0 out CO2 oil slurry 50.0 6 . 2 2 0 . 8 23.0 3 8 . 5 1 . 9 3 0 . 8 28.8 65.5 21.9 12.5 6 8 . 3 6 : 6 2 3 . 1 12.0 3 5 . 7 7 . 2 3 6 . 8 22.3 61.9 6 . 2 28.1 13.8 28.6 2 . 0 36.8 3 2 . 6 42.4 3 . 0 1 8 . 2 3 6 . 4 4 5 . 2 2 . 3 22.6 29.9 4 7 . 4 2 . 8 28.6 21.2 5 9 . 4 5 . 9 29.7 5.0 3 8 . 5 3 . 8 25.7 32.0 56.7 2.5 15.4 25.4 58.3 2 . 9 9 . 7 29.1
the water-gas reaction, the carbon monoxidecarbon dioxide ratio depending upon the temperature in the top section of the converter. The temperature would be lower when refluxing is taking place; hence the carbon dioxide content of the gas would be higher since the water-gas equilibRun No* 4 rium shifts towards higher carbon dioxide par6 8 tial pressures a t lower temperature. 11 The distribution of nitrogen in the products 12 13 is given in Table XIV. Only a fraction of the 14 16-1 total ammonia produced was recovered in the 16-2 aqueous layer separated from the overhead oils. 16-3 It has beeii assumed in constructing Table XIV 17-1 that subtraction of the nitrog>n appearing in 17-2 the overhead oil and heavy oil slurry from the total input would give the amount converted to ammonia. T h e decrease in t h e nitrogen amearine: in the heavv oil slurry%ith increasing temperature i;3’ quite marked (runs 16-1, 16-?, 16-3, 16-4);- concomitant increases in the nitrogen in the c verhead oil and as ammonia are also evident. Since the perce: ,tage of nitrogen in the overhead oils and heavy oil slurries varies little in runs 4 to 17-2, the ratio of the nitrogen contents of these products is approximately the same as their mass ratios.
TABLE XIV. NITROGEN DISTRIBUTION IN PRODUCTS -Pounds
R u n No.
Coal
4 6 8
0.74 1.10 1.71 1.50 0.90 2.64 1.38 0.33 0.29 0.33 0.16 0.16 0.33 0.32
11
12 13 14 16-1 16-2 16-3
18-4
16-5 17-1 17-2
of Nitrogen in:Total Vehiole input
0.38 0.79 1.7.5 1.35 0.67 2.20 1.26 0.28 0 25 0 29 0.14 0.13 0.28 0.28
1.12 1.89 3.46 2.85 1.77 4.84 2.63 0.61 0.54 0.62 0.30 0.29 0.61 0.60
-Nitrogen as % OverHeavy head oil oil slurry 44.6 25.9 63.0 22.3 41.6 24.9 37.9 27.3 35.6 28.3 38.9 31.6 47.9 20.9 63.9 13.1 55.6 18.5 45.2 22.6 33.3 33.3 .62.0 17.2 62.3 16.4 63.3 11.7
of Total InputNH3 in Total aqueous NH3 layer 29.4 18.8 5.3 14.7 33.5 13:4 34.8 11.9 36.1 29.5 3:0 31.1 8.2 23.0 9.3 25.9 12.9 32.2 17.0 33.4 13.8 20.8 11.5 21.3 13.3 25.0
Data on sulfur distribution in the products are given in Table XV. As in the case of ammonia, only a small fraction of the hydrogen sulfide was recovered in the aqueous layer, the bulk of it being absorbed in the sodium hydroxide trap. The total hydrogen sulfide figure is therefore the difference between 100 per cent and the sum of the percentages of sulfur in the overhead oil and heavy oil slurries. Little or no correlation of the percentage of sulfur remaining in the heavy oil slurries or liberated as hydrogen sulfide with temperature or contact time can be found. There is, however, a fairly close parallel between the rate of hydrogen recirculation and
Ratio of Overhead to Heavy
Oil 0.78 0.76 1.23 1.68 1.35 1.38 0.80 0.41 0.62 0.90 1.72 0.47 0.54 0.37
877
these data. Table XV shorn-s that with increasing circulation rate the sulfur content of the heavy oil slurries decreases. This relation is apparently affected to only a minor extent by changes in temperature or contact time and probably consists in displacing a steady state involving hydrogen, hydrogen sulfide, and an organic sulfur compound. I n Table XV there appears to be a correlation between the percentage of the total sulfur appearing in the overhead oil and the temperature in runs 16-1, 16-2, 16-3, and 16-4. This is to be expected, since the overhead-oil to heavy-oil ratio increases from 0.41 in run 16-1 to 1.72 in run 16-4.
DISTRIBUTION IN PRODUCTS TABLE XV. SULFUR
Coal,
Vehicle,
Total Input,
Lb*
Lb.
Lb.
0.74 1.10 1.72 1.50 0.90 2.65 1.37 0.33 0.29 0.33 0.16 0.16 0.33 0.34
0.28 0.59 0.54 0.43 0.37 0.73 0.62 0.14 0.06 0.10 0.04 0.03 0.07 0.09
1.02 1.69 2.26 1.93 1.27 3.38 1.99 0.47 0.35 0.43 0.20 0.19 0.40 0.43
-% Overof Total InputHeavy head oil 10.8
10.7
4.9 10.0 2.3 5.9
i:1 2.9 4.6 5.0 2.5 2.5 2.3
oil slurry 19.6 21.3 39.0 47.5 33.1 55.7 52.8 36.2 40.1 37.2 35.0 42.1 62.5 60.5
Hydrogen Recirculation Rate
---
% of Total Output
Cu. Ft’./ Hr.
Total HIS
250 200 290 180 370 80
69.6 68.0 56.1 42.1 64.6 38.4 47.2 61.7 57.0 58.2 60.0 55.4 35.0 37.2
272 293 265 237 110 80 0
.
HIS in aqueous layer
..
..
2:6 2.3 015 6.4 8.6 7.0 15.0 15.8 7.5 7.0
Acknowledgment The writers wish to thank many Bureau of Mines workers for the indispensable help they have given in this work. C. H. Fisher, Abner Eisner, and Loyal Clarke determined the benzene-insoluble content of heavy oils and pastes, made the distillations of overhead oils, determined their tar acid and base and neutral oil contents, and analyzed the purge and dissolved gases. €3. M. Cooper and his associates in the Coal Analysis Laboratorv made the ultimate analyses of overhead and heavy oils”and determined the carbon dioxide and ammonia content of the water layers. W. A. Selvig and his associates in the Miscellaneous Analysis Laboratory determined the sulfur and chlorine content of the water layers. P. A. Collins, W. L. Fauth, and P. C. Parisi of the Instrument Shop made the high-pressure fittings used in the plant. Irving Spolan and T. E. Brown of the authors’ group rendered valuable service in the operation and maintenance of the plant.
Literature Cited (1) British Fuel Research Board Rept. for Year Ended March, 1937, p. 155, London, H. M. Stationery Office. (2) Gregory, L. B., and Scharmann, W. G., IND.EXQ.CHEM.,29, 514 (1937). (3) Morgan, G., and Veryard, J. T., J . SOC.Chem. Ind.,57, 152-62 (1938). (4) Natl. Bur. Standards, Circ. C410, March 4, 1936. (5) Storch, H. H., Hirst, L. L., and eo-warkers, ISD. ENQ.CHEM., 29, 1377-80 (1937). (6) Weiss, J. M., Ibid., 6, 279-85 (1914). PRBSENTED before the Division of Gas and Fuel Chemietry a t the 96th Meeting of the American Chemical Society, Milwaukee, Wis. Published by permission of the Director, U. 6. Bureau of Mines. (Not subject t o copyright.)
