January 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
about 2 to 5%. Coal tar extraction and purification processes have been found applicable to shale oils, and the products should find a ready market as wood preservatives and in the manufacture of plastics and pharmaceuticals. The tar bases, consisting principally of pyridine and quinoline homologs, are present in about twice the concentration of the tar acids. No large ready market appears available for the tar bases, although their chemical structure suggests numerous uses such as insecticides, chemical intermediates, and pharmaceuticals. The octane number of several pyridine homologs is over 100; this suggests the retention of the bases in the motor fuels if their deleterious properties can be inhibited. LITERATURE CITED (1) Am. Soc. Testing Materials, Designation D 396-48T.
I
(2) Ball, John S.,Dinneen, G. U., Smith, J. R., Bailey, C. W., and Van Meter, Robin, IND. ENG.CHEM.,41, 581 (1949). (3) Belser, Carl, Am. Inst. M i n i n g Met. Engrs., Tech. Pub. 2358 (May 1948). (4) Cane, R. F., Australian Chem. I n s t . J . & Proc., 15, 62 (1948). (5) Cane, R. F., J . Soc. Chem. In.d., 65, 412 (1946). (6) Dinneen, G. U., Bailey, C. W., Smith, J. R., and Ball, John S., Anal. Chem., 19, 992 (1947). (7) Dinneen, G. U., Thompson, C. J., Smith, J. R., and Ball, John S., Ibid., 22, 871-6 (1950). (8) Dulhunty, J. A., Proc. L i n n e a n SOC.N . S . WaEes, 67, pt. 3 and 4, 2 3 8 4 8 (1942). (9) Ibid., 77, 24-32 (1943). (IO) D'yakova, M. K., Petroleum ( L o n d o n ) , 8, 227-46 (1945). (11) Frost, I. C., Stanfield, K. E., McAuley, W.S., and Smith, H. K.,
27
presented before the Divisionof Gas and Fuel Chemistry, 1lSth Meeting AMERICAN CHEMICAL SOCIETY, Chicago, Ill. (12) McKee, Ralph H., and Lyder, E. E., IND. ENG.CHEM.,13, 613 (1921). (13) Murphy, W. I. R., Tihen, S.S..and Cottingham, P. L., presented before the Division of Petroleum Chemistry, AM. CHEM.Soc., San Francisco, Calif., 1949. (14) Secretary of the Interior, tT.S . B u r . M i n e s Rept. Invest. 4457. 35 (1949). (15) Shaw, R. J., Ibid., 4151 (1947). (16) Smith, G. H., and Stewart, D., Scottish Oil Ltd., Central Laboratory, Rept. SO.M/168/40 (July 16, 1940). (17) Smith, J. R., Smith, C. R., Jr., and Dinneen, G. U., Anal. Chem., 22,867-70 (1950). (18) Sohns, H. W., Mitchell, L. E., Cox, R. J., Barnet. W. I.. arid Muruhv. W.I. R.. IND.E N ( . . CHEM..43. 33 (1951). (19) Stanfieid,"K. E., and Frost. I. C., U . S. B u r . M i n e s Rept. Invest. 3977 (1946); 4477 (1949). (20) Taylor, W.J., Wagman. D. D., Williams, >I. G., Piteer, K. S.. and Rossini, F. D., J . Research N a t l . Bur. Standards, 37. 95 (1946). (21) Tisot, P. R., and Horne, Joseph W., U.S. B u r . M i n e s Rept. Invest. 4708 (1950). (22) Van Meter, R. A,, Ned, J. C., Brodie, E. C., and Ball, J. S., presented before the Division of Petroleum Chemistry, 115th .
-
-
~
~
I
Meeting AMERICAN CHEMICAL SOCIETY, San Francisco, Calif. RECEIVED November 21, 1949. This work was done under a cooperative agreement among the Bureau of Mines, United States Department of the Interior, and the University of Wyoming. The oil-shale investigetions were made under the general supervision of W. C. Schroeder, chief, Office of Synthetic Liquid Fuels, R. -4.Cat,tell. chief, Oil-Shale Research and Demonstration Plant Branch, Washington, D. C., and H. P. Rue, chief, Fuels Technology Division. Region IV, a t the petroleum and oil-shale experiment sta tion.
SHALE OIL REFINING J . D. LANKFORD AND C. F. ELLIS 1J. S. Bureau of Mines, Ri$e, Colo.
As a basic approach to the study of the refining of Colorado crude shale oil, thermal cracking and chemical treatment processes were carried out on a demonstration plant scale to explore the variability of yield and quality of finished products and of certain distillates which could be suitable as charge stoclrs for other refining processes. Some flexible thermal operations as topping, visbreaking, recycle cracking, and coking have been made under ex2 ploratory operating conditions, which are not necessarily optimum for the purposes intended, to produce a pipe-line crude, cracked gasolines, coker distillate, and residues.
Various gasolines and Diesel fuels, meeting most of the petroleum industry specifications for such products, have been produced by chemical treatment and by rerunning where necessary. Usage o€ treated cracked gasoline and Diesel fuel in local vehicles and equipment indicates excellent performance characteristics. The thermal cracking studies were made on 100- to 300-barrel-per-day fresh feed charge distillation-cracking plant of industrial type design j the data here could be expected to be duplicated in large scale equipment. This is the first exploratory study on this scale made on crude oil from Colorado oil shale.
T
the work naturally falls into three categories-mining, retorting, and refining. Research and development work on mining oil shale has been done by the mining staff a t Rifle. The techniques and mining methods developed have been markedly successful, and large tonnages of oil shale have been mined at low cost. Lop: cost mining is a prerequisite to the development of an oil-shale industry. I n the field of retorting, several experimental programs are noK under way a t Rifle. The f i s t work undertaken was construction of two batch-type internally fired N-T-U retorts, each with a shale capacity of 40 tons. N-T-U retorts were selected because earlier work by the Bureau of Mines ( 1 ) in 1926-29 a t Rulison, Colo., had shown them to be adapted to Colorado shales, and for initial work a process was needed t h a t would produce oil for refining studies and serve as a starting point for a retorting program. These two units were put into operation in the spring of 1947. A substantial program of experimental operations has been completed, and the retorts now are on a production ba& to supply
HE increased demand for petroleum products resulting from World War I1 and the possibility that supplemental sources
'L
of liquid fuels mag be needed in the future, led to passage of the Synthetic Fuels Act in 1944. This enabling act, of 5 years' duration, and the subsequent 3-year extension act of 1948 authorized the experimental program on synthetic fuels now being conducted by the Bureau of Mines. Under this program, coal and oil shale are being studied as sources of synthetic fuels. The oil-shale work has been divided into two sections. Research and basic studies are being conducted at the Petroleum and Oil-Shale Experiment Station a t Laramie, Wyo. Larger scale pilot- and demonstrationplant work as well as mining research are being carried on a t the Oil-Shale Demonstration Plant at Rifle, Colo. The project a t Rifle is on the Naval Oil-Shale Reserve. To produce shale oil, i t is necessary to mine the shale, crush and screen it to size, and then convert the solid carbonaceous material of the shale to oil by retorting. To produce finished products such as motor and Diesel fuels the crude oil must then be refined. Thus,
28
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 43, No. 1
T.~BLE 1. PROPERTIES OF VARIOESCRUDES FROII COLORADO OIL SII.~LE: Properties of C r u d e Hempel Distillation Products l - i e i d , J-oi, T$ P o 7 Light Heavy Crude Yield Heat Transfer Gravity, S, N, point, Naphtha, distillate, distillate. f r o m Shale, yo Principle Retort 0 A.P.I. wt. % IVt. % F. 392O F,a 592' F . a 804' F." Residue Fischer I s m y H o t gas Gas-flow lfj.5 0.67 2.12 90 2.48 15.51 26.36 54.05 9 5-103 H o t gas Roister 21.2 0.72 1.95 90 5.0 16.0 35.6 42.1 95-100 Internal combustion (hot gas) N-T-L20.3 0 79 2.10 95 2.64 16.48 31.10 48.33 73-85 Indirect Pumphersron 25.7 0.77 1 57 60 17.6 29.4 40.0 27.2 GO-90', a Or-erhead temperature cut point o n distillation; light and heavy distillate cut points: corrected t o 760 nini. b The crude yield expressed as percentage F i x h e r assay of shale is iridely variable, depending on operating conditions in the Pumphcrston retort: 60 to 90% Fischer assay is a n approximate 64urc..
TABLE11. P R O P E R T IOEF ~T w r r
LL
?r'-T-U SHALEOIL
20 3 Gral-itg, 'A.P.1. 129 6 Viscosity S.U.S., 130' F. -18 4 yiscosity: s.u.s., 2100 F. 12.1 Wax content, wt. yo 90 Pour point F. 4,50 Conradson'carbon, wt. 9% 0.70 Sulfur, wt. % 2.10 Xitrogen, wt. 7% Yield S R. naphtha (Hempel dist. 302' F . 760 mm.),vol. Yo 2.7 16 i Yield'liiht distillate (Hempel dist. 372' F, 40 mm.), vol. % X-ield !ieavv dist,il!ate (HemDel dist. 572' F.140 mm.). rol. !7 31 2 PIeld residyium (Hempel dist.), r o l . "0 48.3 Hydrocarbon type analysis of S . R , naplitha'>,vol. % 33 Paraffins a n d naphthenes 48 Olefins 1'1 Aromaticsb 3 6 T a r acids in naphtha (Hempel cut), ~ o l % . 8.1 T a r bases in naphtha (Hempel c u t ) , 1.01. T, a Naphtha from Hempel distillation with tar. acids and tar haws removed b Including sulfur and residual nitrogen compounds.
feed-ctiurgcx rates vary from ahout 100 t o 300 h r r e l s prr cia>-, d(.pending on the type operation. The treating plant was designed chicfly for motor-fucl frac'tion~. hut provisions ]%-ereincorporated for Diexl-fuel treatmerit also. In a typical operation, naphtha from the d i s t i l l a t i o ~ ~ - ~ ~ ~ ~ ~ c k plant is washed wit,h caustic soda arid dilutc, sulfuric acid to r(>move tar acide and tar bases andisthen given a three-stage countercurrent treatment v i t h concentrated sulfuric acid---that i stages of sludge acid followed by one stage of frcsh acid. Rc ation between stages of treating is used for maintaining temperature control. The treated naphtha then is lmter-11-asheti, neutralized, and rerun to remove polymers and correct the enti point. *4 continuous doctor siveet!ener is nvnilaiile if a s~veetcning step is needed. SELECTIOW O F REFISING PROCESSES
In the selection of shale-oil refining processes, it \%-asnccrrsnry to consider a number of factors including the physical and chemical properties of the crude shale oil, the products desired, and thcl limitations of known processes in yielding the desired products. Crude shale oil has properties that vary somewhat v i t h th(a method of retorting. The variation of properties of a, nuinher of
shale oil to the project and t,o cooperative investigat,ors. AIore promising retorting processes have been developed in the course of other concurrent experimental work. One of these, the gasflair- continuous process, has been extensively tested on a pilot illant scale and has several feat'ures n-hich are quite promising. Iniprovements o n the gas-flow retort and the development of several other retorting processes are now under way. TABLE 111. The last major processing equipment to be installed a t Rifle was the shale-oil refinery. Refinery construction as completed in the early summer of 1949, and the first trial runs \?.ere made in the Uields:, 1-01, % ensuing months. REFINERY DESIGN A S D CONSTRUCTION
The refinery consists of a distillation cracking plant and a chemical treating plant (3). Figure 1 is a n aerial viexy of the refinery. Floa diagrams of the respective plants are shomn in Figures 2, 3, and 4. The distillation cracking plant was designed for broad operating flexibilitv. Easily changed heater and process piping connections were provided so that alternate operating procedures can be carried on to include atmospheric distillation, visbreaking, recycle cracking, coking, and reforming. The thermal cracking equipment was designed on the smallest scale t h a t could retain features and equipment found in standard petroleum refining practice and give data that could be extrapolated readily to large size operations. Shale oil was expected to have a high coke-forming tendency in the heater tubes, with a resulting high pressure drop and short on-stream time. Heater tube diameter, therefore, was the controlling limitation in designing the heater. Tubes were installed having an inside diameter of '/8 inch which was considered to be the smallest practical size tube. Fresh
DISTILLATIOX OPERATIOX OK X-T-1; SHALEOIL
;~TJIOSPHERIC
Properties Gravity, 3.A.P.I. Sulfur, wt. yo Sitrogen, vol. % T a r acids, vol. % T a r bases, vol. % Octane S o . . h f . M . a , clear 1 mi. T E L +3 ml. T E L Octane No., Research, clear +1 ml TCL -3 ml. TEL Cetane S o . Hydrocarbon anslysi-b, 7-01 % Olefins Aromatics Paraffins and nap!ithenes
Crude charge 100 20.9
0.8 1.96
+
A.S.T.11. distillation (cor. t o 760 nim. H g ) , O F . Initial b.p. 373 +96 10% 20% ,265 50% 679 90% End point
P r o d u c t Yields a n d Properties Crude Light Heavy Reduced naphtha g a i oil gas oil crude 6.4 13.3 32.1 46.0
42.8 0.93 1.55 2.7 7.9 58.4 61.2 66.5 68.9 21.8 14.0
28.0
0.91 1.49 3.5 7.6
22.5 0.78
15 . 0
36
44.7 25.5 29.8
146
319
336
363
412 468
444 464 470 518 623 684
398 628
658
295 (81 863
Test-Period Operating Conditions Charging rate, bbI./stream-day: Raw crude, Recycle stock
Temperature, F. Pressure, lb./sq. inch gage a
hlotor method.
b Xeutral-oil basis.
Gas, coke a n d loss 2.2
Heater Inlet Outlet 186 760 270 15
Flash Chamber, TOP 616
240 0 Fractionator Bottom 300 567 7
Top
January 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
Figure 1.
29
Shale Oil Refinery
Distillation cracking plant and treating plant (upper center)t all tanks are served by pump house (lower center)
Colorado crude shale oils, all of which were produced from Green River oil shale, is shown in Table I. The shale oil produced by the gas-flow process and the N-T-U process are similar, although the gas-flow oil has a lower A.P.I. gravity. Both oils are produced in retorts where heat is transferred to the crushed shale by hot gases. This process of heat transfer to the oil shale is the most desirable, and N-T-U crude oil, which is representative of such a process, was chosen as typical for refining studies. The old-style Pumpherston retort was not suitable for Colorado shale (1). Because of high retort temperatures, the Pumpherston retort produced a more highly cracked crude than the N-T-U or gas-flow processes with subsequent lower yields of oil than are produced by
i-l
FLASH
STRlPf ER
FR& CT I ONATOR
the gas-flow retort. Cracking under controlled conditions in refinery equipment is considered preferable to cracking in the retort. Table I1 shows a n analysis of a typical N-T-U shale oil. I t will be observed t h a t the oil is heavy and viscous and t h a t it is quite waxy; the pour point is 90" F. The sulfur content of the crude is about 0.8 weight yo,and unlike most crude petroleums there is present about 2.0 weight yo nitrogen. Only a small quantity of straight-run naphtha, less than 3%, is present, and a vacuum distillation t o 572" F. at 40 mm. leaves a residuum equal to almost half of the crude charge. The naphtha fraction contains about 3.6 volume yo tar acids and about 8.0 volume % tar bases. i l l -
,
c
t
PESIDUUY
Figure 2.
STABILIZED NAPHTHA T O TREATER
Shale Oil Cracking Plant
CHARBE
0ASOUME
INDUSTRIAL AND ENGINEERING CHEMISTRY
DILUTE
OILUTE
11
IST. STAQE
-
Vol. 43, No. 1
3 RD.
2 ND.
CAUSTIC XEUTAA L l Z E R
COALESCER
SPENT' CAUSTlf TAR
ACIDS
SPENT ACID
TAR
-
SLUDQE ACID
FRESH ACID
TREATED DISTILLATE
BASES
Figure 3.
Continuous Acid Treater
to pioc.css shale oil were the basw for t>hr>installation of the nimt one half of the naphtha fraction is composed of olefins; thermal-cracking about two tenths consist of aromatics; and the remainder, about __ -plant a t Rifle. It would be desirable to use catalytic cracking for shale oil for three tenths, is made up of paraffins and naphthenes. the same reamns it is used in petroleum refining. However, satisI t is evident therefore, that several problems confront the shalefactory catalysts for shale-oil cracking have not been developed. oil refiner. The high wax content and viscosity make it difficult Petroleum-refining catalysts and operating conditions, when used to transport the crude oil by pipe line without some treatment to for shale-oil cracking, result in high formation of gas and depoimprove flow characteristics, such as visbreaking or dewaxing. sition of coke on the catalyst. Nitrogen conipounds in the Topping would yield only a small quantity of poor quality shale oil have the effect of decreasing the activity of petrolcumnaphtha; the gas oil would be of high pour point; and a relatively cracking catalysts, and these nitrogen compounds also are large quantity of high viscosity residuum would remain. Itethought t o be responsible for coke deposition on the catalyst. An nioval or drastic reduction of nitrogen and sulfur compounds as explanation may be that the nitrogen compounds are basic and well as tar acids and tar bases from the distillates would be necessary to prepare satisfactory products. From the standpoint of present liquid fuel requirements, by far the major produetion must be of lighter TABLE IT'. SCM.rJlARY O F YIYBRE l K I S G OPERATIONS fractions, motor and Diesel fuels. Shale oil or l'soduct Yields and F'rgpertioa -an?; source of liquid fuels, i t appears, should Crude Crude Light Heavy Gas, coke. be aimed toward the production of gasoline and charge naphtha gas oil gas oil Residuum and loss Diesel fuels. Yields. vol. % 100 0.7 19.8 44.3 24.4 1.8 Properties " Thermal cracking of shale oil appears the first Gravity. 'A.P.1. 20.6 51.1 31 1 '71 6 11.6 Sulfur, wt. % 0.83 1.0G 0.84 0.72 0 ti9 logical refining step toward this goal. Thermal Sitlogen, wt. % 1.90 0.93 1.31 1.89 2 , .if; cracking offers wide flexibility; by varying the T a r acids, vol. % 1.6 2.0 3.0 1.8 T a r bases, vol. "/F 3.0 7,9 !LO '1 4 severity of thermal treatment, both yield and Cetane KO. 20,o Octane K O A 1 . A I . a 68.4 character of products can be altered within broad Hydrocash& arialysish, linlits. As examples, visbreaking could be used vol. % Olefins 50.0 to prepare pipe-line oil; recycle cracking could Aroiiiatics 14.3 Paraffins and naphttiene; 3.5.7 be employed to convert the crude into a fairly A. 8. T. RI. d i a t i 1la t io n large proportion of lighter fuel fractions leaving (cos. to 7(iO i i i i i i . € l a ) , I'. a usable heavy fuel; and coking could he used 196 Initial b.1,. 362 111 2.57 517 322 103 194 448 630 10% to yield a higher percentage of distillates without ?0". 361 246 4d8 652 .>0463 2 316 408 892 any heavy residual fuel. The distillate oils from 9o.r 370 578 pint 401 625 the various modes of thermal cracking could be chemically treated for finished products, or Test-I'criod Opeiating Conditions thermal cracking could be considered as a ferdXU!). 3 Charging rate, bbl./streaiii-day: Raw crude Recycle stock 0 stock preparation for other refining process~s. Heater F l a s h ~ t ~ ~ , , ~ Fractionator b ~ ~ , Recent developments in the m e of coking to Inlet Outlet Top 'rot, Bottom prepare hydrogenation feed stocks appear favor774 187 900 313 882 Teini,rratrire O F. able and are discussed later. Ttie preceding conI'reasrire, lb.)sq. inch gagp 290 120 1:3 siderations and the fact that thermal-cracking * Motor method. b Seritral-oil basis. equipment is available ill most refineries and t>he possibility t h a t this equipiiwnt niight be adaptcd
INDUSTRIAL AND ENGINEERING CHEMISTRY
January 1951
SWEETENED
SPENT DOCTOR
Figure 4.
TABLE V.
C o n t i n u o u s Doctor Treater
SUMMARY OF RECYCLE CRACKING OPERATIONS
I
Crude charge 100
Yields, vol. % Properties Gravity, 'A.P.I. 21 1 0 87 Sulfur, wt. yo Nitrogen wt. o/ 1.88 Tar acidd, vol. T a r bases vol Octane N b h;~.Xi.a Hydrocarbgn analysisb, vol. % Olefine Aromatios Paraffins and naphthenes A.S.T.M. distillation (cor. to 760 mm. H.g) e F. I n i t i h b.p 37 1 49 1 10% 5.57 636 point
%
EJ
Product Yields and Properties Recycle Crude stock naphtha Residuum 50.3 46.2 16 8 0.73 2.52
54.4 0 62 0.97 2 2 7 1 68 3
3.5
5.5 0 63 2.87
55 15 30 273 456 472 517
93 149 195 306 400 411
228 361 620
Test-Pet iod Operating Conditions Charging rate, bbl./stream-day: R s w crude Recycle stock Heater Flash Chamber, Inlet Outlet TOP Temperature, F, 460 910 755 Pressure, Ib./sq. inch gage 930 150 52 a Motor method. b Xeutral-oil basis.
92.5 224.6 Fraotionator Top Bottom 385 632
a d the yield of reduced crude was 46.0%. Topping runs were made primarily as a n equipment test for atmospheric distillation. Because of the low distillate yields, it is not expected t h a t additional atmospheric runs will be made except under unusual circumstances. The products of topping operations were quite similar to those obtained by laboratory scale distillations. The small naphtha fraction was lacking in light ends and was high in nitrogen and sulfur. The octane number was marginal. The results of visbreaking operations are shown in Table TV: the yield of crude naphtha was increased about soy0 over that of the atmospheric distillation run; the yield of the combined gasoil streams was increased about 40% over t h a t of the atmospheric distillation run; and the residuum yield decreased about 47%. The gasoline boiling range and octane number were improved. The sulfur content of the visbroken crude naphtha remained about the same as t h a t of the straightrun naphtha, but the nitrogen content was reduced by about 40%. The quantity of tar acids and bases of the crude naphthas and light gas oils for the two runs remained substantially the same. The cetane number of the untreated light gas oil from visbreaking operations was lower than that from atmospheric distillation operations. This may be due t o tar bases, but the effect of tar bases on cetane number is not well understood. In the course of the experimental operations, several recycle cracking runs were made. The results of .a typical recycle run charging crude shale oil are shown in Table V. In this run only two liquid products were made-naphtha and residue in about equal proportions. Recycle cracking produced naphtha still deficient in low
TABLE VI.
most cracking catalysts acidic. Removal of nitrogen compounds from catalytic cracking charge stocks or the development of a catalyst unaffected by nitrogenous compounds are two approaches to the catalytic cracking problem. REFINERY OPERATIONS
v
The refinery operations beginning in midsummer, 1949, have served chiefly as trial runs and shakedown tests, and for that reason this paper must be considered 9s a progress report. The data are not intended to present conclusive results and may serve no purpose other than to indicate trends. The first refinery run was on atmospheric distillation. A summary of the data obtained on a topping run is presenhd in Table 111. The distillation equipment operated satisfactorily, with only minor mechanical difficulties: the naphtha yield was small, 6.4%; the sum of the .yields of the light and heavy gas oil8 amounted to 45.4%;
SUMMARY OF COKING OPERATIONS
Yields, vol. % Pro erties GPravity, ~ A . P . I . Sulfur, wt. yo Nitrogen, wt. % Tar acids vol. % Tar bases' vol. % Cetane ~ b . Octane No M.MSa Hydrocarb& analysisb, vol. % Olefins Aromatics Paraffins aqd naphthenes A.S.T.M. distillation (cor. to 760 mm. Hg.), O F. Initial b.p. 50%
E3 point
31
Crude charge 100 20.6 0.82 1.90 1.6 3.0
Product Yiclds and Properties Crude Ltght Heavy naphtha gas oil gas oil 13.1 31.2 46.3 45.3 1.08 1.25 2.4 8.0 65
29.1 0.84 1 .GG 2.2 12.6 31
18.1 0.67 2.17 0.5 0.6
53 14 33
253 496 567 674
133 235 287 350 40.6 419
484 523 543 589 690 69 1
389 642 661 697
Test-Period Operating Conditions Charging rate, bbl./stream-day: Raw crude Recycle stock
Temperature F. Pressure, 1b.jsq. inch gage a
b
Motor method. Neutral-oil basis.
Gas, coke, and loss 9.4
Heater Inlet Outlet 184 903 210 20
Flash Chamber,
TOP 770 7
222.2 0
Fraat'ionator
Top 340
Bottom 691
32
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 43, No. I
The cracking plant was operated as a delayed coker follo~viiig the other types of operation. The conditions of operation and the Raw Coked Hydrogenated Natural results of this run are shown in Table VI. The total yield of tiisShale Oil Shale Oil Shale Oil Petroleuma tillate products from coking is about 90%. Original raw shale oil, Delayed coking is being considered as the first step in a revol. % 100.0 86.7 88.4 ... 44.9 20.5 43.6 32.8 Gravity, 'A.P.1. fining scheme (4)in which recycle coking would be used to pro0.01 h-itrogen, wt. % 1.93 1.50 0.82 Sulfur, wt. yc 0.70 0.01 0.11 duce a 700" F. end point coker distillate. Preparation of tlie 1.12 0.60 A-il Oxygen, wt. 7% coker distillate would in effect improve the carbon to hydrogen 84.9 Carbon, wt. Yo 84.70 ... 8i.'89 12.3 11.43 Hydrogen, wt. % ... 14.0 ratio by removing excess carbon. The highly reactive coker dis7.41 C : H ratio 6.90 6.13 . . . 23 Pour point, F. 90
