218
INDUSTRIAL AND ENGINEERING CHEMISTRY
$240,967,000 as against $244,855,000 in 1928. The average valuation of last year's imports was thus only 19 cents per pound as compared with 25 cents in 1928. This, however, was undoubtedly due in part to a shifting in the trade by which we purchased a much greater proportion direct from Ceylon and British Malaya than before, the average valuation being the declared value a t the ports of those regions instead of at English ports through which the rubber was transshipped. Imports credited in our statistics to the United Kingdom fell from 108,305,000 pounds in 1928 to 9,864,000 pounds last year, while direct imports from British Malaya rose from 558,773,000 pounds to 896,000,000 pounds and from Ceylon from 82,700,000 pounds to 120,989,000 pounds. Imports from Brazil dropped from 25,380,000 pounds to 23,176,000 pounds. Naval Stores, Gums, and Resins
Shellac, the largest item among the imports of varnish gums, recorded a notable gain in 1929, reaching a total of
Vol. 22, No. 3
33,335,000 pounds valued a t $12,789,000, as against 24,056,000 pounds valued a t $10,210,000 in 1928. In addition lac in other forms was imported to the extent of 7,976,000 pounds valued a t $2,579,000. Damar gum, 19,131,000 pounds valued a t $2,403,000, was about 20 per cent higher than in 1928. Shipments of chicle grew from 12,435,000 pounds to 13,223,000 pounds. Natural camphor, crude and refined, totaled 5,635,000 pounds as against 5,541,000 pounds in 1928, and synthetic camphor 3,957,000 pounds against 2,265,000 pounds in the earlier year. Exports of naval stores, gums, and resins rose from a value of $26,433,000 in 1928 to $30,998,000 in 1929. Both rosin and turpentine shared in the increase. Rosin exports were 1,437,000 barrels valued a t 820,442,000 as compared with 1,174,000 barrels valued a t $17,617,000 in 1928, while gum spirits of turpentine stood a t 16,304,000 gallons valued a t $8,530,000, compared with 12,510,000 gallons with a value of $6,678,000 in 1928. The United Kingdom and Germany were the largest buyers of both commodities.
The Edeleanu Process for Refining Petroleum' Robert L. Brandt AGEFCI, 11 WEST4
2 Sr., ~ NEW ~ YORK.N. Y .
A process for the refining of petroleum is described Disadvantages of Sulfuric E T R O L E U M oils, Acid as Treating Agent which uses as the treating agent liquid sulfur dioxide. though o c c u r r i n g i n The process is shown to give excellent results especially w i d e l y separated reThe action of sulfuric acid in the removal of sulfur and nitrogenous compounds gions and in deposits of varyi s p a r t l y c h e m i c a l , partly and to have overcome many of the disadvantages ing geologic ages, show a rep h y s i c a l . Owing to the inherent in the sulfuric,acid method of refining. Analymarkable constancy of ultihighly complicated reactions ses of the products show them to be superior to those mate composition. That is, involved, the action between obtained by the usual methods. Pressure distillate while an enormous number of sulfuric acid and a distillate hydrocarbons may be present can be processed by this method so that the antiknock may proceed along a number in a crude oil, yet in the main properties of the finished gasoline are greatly improved. of p a t h s . Polymerization, it is possible to classify them Cost data are given for a plant treating kerosene and s u l f o n a t i o n , and oxidation within a few homologous light oils and also for a plant treating lubricating oil. c e r t a i n l y occur. Some of series. Hydrocarbons of four t h e r e a c t i o n products are predominating types are recognized-paraffins, naphthenes, removed from the oil layer owing to the selec'tive solvent aromatics, and unsaturated compounds. I n addition, ele- action of the resultant acid-sludge, others are oil-soluble and mentary sulfur and sulfur compounds such as mercaptans remain in the oil layer. Treatment with acid is thus unsatisand sulfides, nitrogen compounds, naphthenic acids, phenols, factory in many respects. Heavy loss of hydrocarbons in resin- and asphalt-like compounds are in general present in the acid layer that up to the present cannot be economically distillates derived from crude petroleum. The hydrocarbons recovered; undesirable polymerization and oxidation, range in physical characteristics from gases, through low whereby higher boiling and more viscous hydrocarbons are specific gravity non-viscous oils, to solids such as paraffin formed; sulfonation, whereby valuable aromatics are lost; and asphalt. It is the problem of the refiner to separate the oxidation of organic sulfur compounds with the formation of various hydrocarbons contained in the crude into mixtures of free sulfur; darkening in color of the heavy lubricating distillates; and the difficulty a t times encountered in the formaempirical properties. The preliminary separation of a raw crude into the various tion of emulsions during large-scale treatment are only a few products such as gasoline, kerosene, etc., is effected by dis- of the disadvantages inherent in the sulfuric acid method. tillation. In recent years great strides have been taken in Basis of Sulfur Dioxide Process this direction. It is now possible economically to fractionate These disadvantages may be overcome to a very considervery closely, to apply high-vacuum low-temperature distillation, to attain relatively high thermal efficiency, and to pro- able extent by the use of liquid sulfur dioxide a t low tempersduce distillates with a minimum of pyrolysis. Also in the tures. This method, first proposed by L. Edeleanu and actual refining of the distillates, to render them marketable, finally worked out for commercial use by him and his coconsiderable advance has obtained from a mechanical stand- workers, is based on the difference in solubility in liquid point. Continuous acid and clay treatment, high-tempera- sulfur dioxide at varying temperatures of the four main groups ture filtration, centrifuging out of acid sludge, and economical that make up a petroleum distillate. In general, the higher recovery of spent acid are a few examples. Kevertheless, the boiling paraffins, naphthenes, and naphthenic acids (over major agent used for the removal of undesirable constituents 175" C.) are insoluble a t reasonably low temperatures from the distillates is the one originally proposed-sulfuric (-10' C.), aromatics are miscible in all proportions a t all temperatures, as are the true unsaturated hydrocarbons arid. (containing two or more double bonds). 1 Received January 27, 1930.
P
INDUSTRIAL AND ENGINEERING CHEMISTRY
March, 1930 Table-I-Yield
of Extract from Kerosene Distillate a t Varying Temperatures
(1part by weight distillate t o TEMP. MEXICO PERC OC. 70 % 25.5 -10 25.9 - 9 23.4 - 8 24:s 2 3 , 2
- 7 - 6 - 5 - 4 - 3
- 2 - 1 0
-
+
3 4 5 6
7
8 9 10 11 12 13 14 15
I
.
..
*/a part by weight SOz)
ROUMANIA Urycz Moreni
R 25.4 24.8
..
..
24:3
..
23:7 22:7
22.6 "2.4
23:4
2i:6
22.1
?i:4
23:1
..
22.7
2i:e
2i:2
2i:o
20: 8 20.3 19.9
zi:i
14:1
19:4 18.8
10:1
17:7
6:6
24.1
.. ..
20:4 19.5 19.0 18.2
17:8 17.1 16.5 l5,9
..
..
..
Complete miscibility above -9' C.
..
..
2i:s
DUTCH EASTINDIES
%
17.2
16:s
16'6
15:o
..
Mexican oils. The nature of the sulfur compounds in the crude as recovered from the ground is practically unknown. Considerable study has been given to the sulfur compounds occurring in the lighter distillates, and a t present it appears that relatively unstable sulfur compounds, such as mercaptans, are formed during distillation. The effects on motors of a high sulfur content in gasoline are debatable, and a vast amount of money is expended yearly by the petroleum industry to bring the sulfur content within specified limits. Beyond a doubt sulfur must be brought to a very low value in kerosene else troubles in usage are inevitable.
17:o
..
Table 11-Effect of Sulfur Dioxide on Sulfur Reduction i n Kerosene Distillates of Approximately the Same Boiling Range (100 per cent by volume SO2 countercurrent treatment) SULFUR IU DISTILLATE ORIGIN Raw distillate After SO, extraction
20.4
19:o 18.5 17.9
219
West Texas Reagan Winkler Panhandle Pecos Crane Upton Hull Arkansas Venezuela Texas Coastal Oklahoma Trinidad California
3:0 Complete miscibility
12.9
Sulfur and its organic combinations, nitrogen compounds, and resin- and asphalt-like compounds are soluble in liquid sulfur dioxide, though their solubilities decrease with increasing complexity of the molecule. Sulfur compounds are especially soluble. It is apparent that the presence of such a wide variety of differently constituted hydrocarbons will involve extremely complicated solubility relationships-i. e., the solubility of the distillate in sulfur dioxide, which varies over a B-ide range depending on the source and type of distillate, the temperature employed, the solubility of the extract in the refined oil, etc. For example, although a pure paraffin of medium boiling range is quantitatively insoluble in liquid sulfur dioxide a t -10' C., and an aromatic-like benzene is miscible in all proportions, when hoth are present they exert a mutual solubility effect on each other and hence we never obtain an absolutely clean-cut separation. Kevertheless, separation for refining purposes is entirely satisfactory, as will be shown later; in certain cases extraction with liquid sulfur dioxide may even be quantitatively employed in the laboratory. Advantages of Sulfur Dioxide Process
YIELDOF EXTRACT-The percentage of material, which we term "extract," removed from a distillate by means of liquid sulfur dioxide varies widely. For example, in a Dutch East Indies kerosene distillate complete miscibility of the distillate and Liquid sulfur dioxide ensues a t all temperatures above -9' C., owing to the extremely high aromatic content of the oil, whereas certain Pennsylvanian cylinder stocks yield only
%
%
0 19 0 45 0 15
0 07 0 07 0 0.5
0 625 0 49 0 10
0 11 0 09 0 03
Free sulfur in the amorphous state is quite soluble in liquid sulfur dioxide but the crystalline form is only sparingly so. Fortunately, free sulfur in distillates is nearly always in the amorphous state. It is impossible, of course, to remove all traces of sulfur or its compounds from distillates with liquid sulfuric dioxide as equilibrium is always set up between the oil phase and sulfur dioxide phase. The data on sulfur removal in Table I1 show that we hare here an excellent means for overcoming the sulfur problem. The importance of this factor is evident when it is considered that enormous new sources of crude hat e been developed recently-for example, in western Texas-that contain very high percentages of sulfur both as hydrogen sulfide and in organic combination. In most cases with the very high sulfur oils a light acid treatment following sulfur dioxide treatment (3 to 6 pounds 66" Be. HzS04per barrel) brings the sulfur to below 0.05 per cent. I n addition, a light doctor solution wash is required to remove any low molecular weight mercaptans present. REXOVAL OF SITROGEN Comoums-Evidence2 to date seems to indicate that liquid sulfur dioxide completely removes nitrogen compounds from a t least the lighter distillates (California) and that two distinct classes of nitrogen hydrocarbons may be present, one soluble and the other insoluble in weak acid. Nothing is known concerning the structure of the latter class.
Table 111-Change in Physical Properties of Oils on Treatment with Sulfur Dioxide ORICITALOIL
R.4FFINATE
EXTRACT
ORIGIK
-
Gravity a
Midcontinent Midcontinent Gulf Coast, Texas California
.4.
P. I.
22.8 28.6 18.5 23.4
\'isc. 100' F. Flash Sec.
259 69 1968 104
F 410 340 450 330
Fire
F. 470 390 520 380
Gravity Visc. 100' F.
A . P.I. 29.7 34.4 21.4 27.4
3 per cent of extract. The effect of temperature change on the yield of extract is shown in Table I. Analysis shows a very high aromatic content of a Dutch East Indies kerosene distillate and its effect on the solubility of the paraffins in sulfur dioxide is shown in Table I. SULFUR REMOVAL-sulfur removal in the knerican petroleum industry is extremely important. Crudes vary in sulfur content from 0.05 Der cent in certain Pennsvlvanian and West Virginian crudes i o 4.5 per cent in somi Californian and
Sec. 180 64 1421 99
Flash
Fire
Yield
F.
' F.
70
425 345 450 350
480 385 515 380
74.2 75.5 83.6 76.0
Sp. gr.
Yield
1.052 0,988 1. 0.995
25.8 24.5 16.4 24.0
'70
+
Description of Process for Light Oils
A flow sheet of a modern continuous plant for light oils is shown. The first step in the process consists in removing water from the raw incoming distillate. When treating heavy lubricating oils this is accomplished by blowing the stock with air in conventional blow pans if the stock is very wet. Ordinarily the water content may be lowered sufficiently by
* J. R . Bailey, private communication.
220
INDUSTRIAL AND ENGINEERIhlG CHEMISTRY
merely settling the raw stock for a few days. I n the case of lighter oils dehydration is effected by passing the distillate by gravity from the refinery feed tank through a small tower (not shown) filled with rock salt. From this apparatus the material is dropped into a capacity tank and passed to an elevated horizontal tank, where any air dissolved in the oil is removed by means of a vacuum pump, whose suction is connected to a dome located on top of the tank. The distillate is now ready for processing. It is picked up from the bottom of the vacuum tank by a centrifugal pump, and passed in series through two sets of double-pipe cold exchangers, where its temperature is reduced to the desired point previous t o its entry into the mixer. I n the first unit cooling is accomplished by means of cold raffinate (refined oil) that has already passed through the mixer. In the second unit cold liquid sulfur dioxide is passed through the inner pipe. The cold distillate next enters near the bottom of the mixer for treatment with cold liquid sulfur dioxide. Light oils require between 50 and 100 per cent sulfur dioxide by volume for treatment, while the heavier oils require somewhat more. The amount of sulfur dioxide necessary is dependent upon the character of the distillate and the degree of refinement desired. The mixer for light oils is a hollow vertical tower about 30 inches in diameter and 20 feet high. It is heavily insulated with cork to prevent thermal losses, filled with Raschig rings to promote intimate mixing of the oil with sulfur dioxide, is fitted with sight glasses for control purposes. Cold raw distillate enters near the bottom, passes through a spreader, and rises to the top of the tower. Fresh cold sulfur dioxide enters near the top of the tower, passes through a spreader, and drops to the bottom, scrubbing the counter-flowing stream of distillate in its descent. Owing to the selective solubility effect of cold liquid sulfur dioxide for aromatic, unsaturated, sulfur, nitrogen, asphalt, and other compounds, the distillate is freed from these impurities in its passage through the tower. Separation of the raffinate and the extract takes place readily on account of the large difference between their spe-
Vol. 22, No. 3
cific gravities. We thus have a stream of raffinate continuously discharging from the top of the mixer into the refined-oil tank, and from the bottom of the tower a stream of extract flowing to the extract tank. The extract consists of about 85 per cent sulfur dioxide and 15 per cent oil, while the raffinate contains about 10 per cent sulfur dioxide. The next steps in the process are to recover the sulfur dioxide from the raffinate and extract for re-use in the system. The handling of the raffinate will be discussed first. FLOW OF REFINED OIL-Connected to the bottom of the refined-oil tank is a centrifugal pump that passes the raffinate through the first double-pipe cold exchanger, the distillate precooler. I n this apparatus it is warmed to about atmospheric temperature and in turn cools the raw entering distillate to around 30" F. It next flows through the preheater, a double-pipe exchanger, where its temperature is raised by means of the counter-flowing stream of hot raffinate discharged from the final evaporator. Leaving the preheater the raffinate passes through a nest of steam-heated tubes connected to the evaporator, where its temperature is raised to about 150' F., finally entering the shell of the evaporator, where separation of the oil and gaseous sulfur dioxide takes place. The hot sulfur dioxide gas is led directly from a small dome on top of the shell to a conventional water-cooled condenser located outside of the Edeleanu plant building. The hot raffinate, still containing some sulfur dioxide, is forced by the vapor pressure of the sulfur dioxide gas in the first effect to the medium stage evaporator. Its temperature is maintained constant by means of steam. The vapor space of this effect is connected to the suction of compressors that maintain about a 10-inch vacuum upon the apparatus. Removal of the final traces of sulfur dioxide from the raffinate is accomplished in the low-pressure evaporator, where a vacuum of about 0.47 inch is held by means of vacuum pumps. Finished raffinate is removed from the bottom of the shell of the final evaporator by means of a centrifugal pump, and from this point passes through the preheater, where it is cooled, to a refinery rundown tank.
, :I
t ,
'
,
.. ,
...
.... . , ., . . ,
,
'
,
. , , .../ ,
.I
,
.
,
..
,. r I.. 2 % t . . . : : . ' / / I . ,,:I..$, ,$.I ' , : < , .1 , . I . . / .
the
I S D U S T R I A L A S D ESGISEERI.VG CHEMISTRY
March, 1930
A typical Californian kerosene extract assays ai: follows: yiscosity a t 100' F.. . . . . . . . , 6 5 sec. .4. P. I.. . . . . . . . . . . . . . . . .. 2 4 . 5
Flash.. . . . . . . . . . . . . . . . .,145' F. Fire.. . . . . . . . . . . . . . . . . .,170' F.
ENGLER DISTILLATIOK
5% In 10 20 30
OF. 324
390
414 430
223
T a b l e \'-Operating
Costs (Continued)
Labor:
' o " , ~ ~ & ~ }~. . . ~. . . .f. . .$. . . .~. . . ~. . . .e. . . ~. . ~ =~ y6 6 , O O
Maintenance and repairs: $12 000 per year (360 days). . . . . . . . Supplies: $3500 per year (366 days). . . . . . . . . . . . . . . . . . . . . . . ~~
%
O F .
R
40 50 60 70
444 456 468 482
80 90 95 97
OF. 497 522 555 595
costs
Operating costs are shown in Table V. T a b l e V--Operating C o s t s Assume the plants to he driven by electricity, and the evaporators to he heated with exhaust steam. A N D LIGHTOILS PLANTFOR TREATISGKEROSEWE Capacity 500 tons per day (3800 hbls.) using 75 per cent sulfur dioxide (by volume) Electrical power: 7320 kilowatt-hours 1 kilowatt-hour a t 1 cent = S73,20 per d a y . . . . . . . . . . . . . . . . . . . . . . . Steam (exhaust): 232,200 pounds per 1000 pounds a t 10 cents = 23.22 day.,......................... Water (recooled and reused): 70,000 gallons per d a y . . . . . . . . . . . . . . . . . 1000 gallons a t 2.2 cents = 1,54 Sulfur dioxide: 2500 pounds per day. 1 pound a t 1.8 cents = 45.00
= =
33.33
9.72 -
Total cost per 24 hours. . . . . . . . . . . . . . . . . . . . . . . . . . = $252.01 Operating cost per metric ton of distillate. . . . . . . . . . . . . . = 0 504 Operating cost per barrel of d i d l a t e . . . . . . . . . . . . . . . . . . = 0.067 PLANTFOR TREATIXG LTJBRICATING OIL Capacity 500 tons per day (3500 hbls.) using 200 per cent sulfur dioxide (115volume) Electrical power: 10.080 kilowatthours per day. . . . . . . . . . . . . . . . . . . 1 kilowatt-hour at 1 cent = P l O O . SO Steam: 338,000 pounds exhaust steam.. . . 1000 pounds a t 10 cents = 3 3 , K 42,000 pounds live steam.. . . . . . . 1000 pounds a t 50 cents= 31 . O O Water (recooled and reused): 100,000 gallons per d a y . . . . . . . . . . . . . . . . . . 1000 gallons a t 2.2 cents = 2.20 Sulfur dioxide: 2250 pounds per day. 1 pound a t 1.8 cents = 4 0 . 50 T.ahor.
7" f p , r , e ~ ~ s ]~. . .~. . . ~. . . .~. . .~. . . .~. . .~. . . ~. . . ~ $= ~ 66y 00
Maintenance and repairs: $12,000 per year (360 days). , . . , . . Supplies: $3500 per year (360 days). . . . . . . . . . . . . . . . . . . . . .
=
=
33.33 9.72
Total cost per 24 hours. . . . . . . . . . . . . . . . . . . . . . . . . . = $307.35 Operating cost per metric ton of distillate. . . . . . . . . . . . . . = 0.615 Operating cost per barrel of distillate.. . . . . . . . . . . . . . . . . = 0. OSS.
Insulating Board from Straw' Albert G. Gibson STEWART I a s o BOARDCOMPAWY, S T JOSEPH,hlo.
T
HE utilization of farm wastes as the raw material for manufacturing processes has attracted much attention in recent years. Cereal straws, among which wheat straw is by far the most important, offer an annual supply of inaterial in tremendous amounts in the majority of our states. Table I shows the annual wheat production in the United States for the years 1920 to 1928, inclusive @ I ) , together with a conservative estimate of the amount of straw corresponding to this production, based on a figure of 1 ton of straw to 15 bushels of wheat. With an average production of 818 million bushels of wheat per year over the 9-year period, the average amount of straw available annually was over 54 million tons. T a b l e I-Annual W h e a t P r o d u c t i o n of U n i t e d S t a t e s a n d Available W h e a t S t r a w f o r t h e Years 1920 to 1928, Inclusive YEAR TOTALWHEATPRODUCED AVAILABLE STRAN Million bushels Million tons 55.53 1920 54.33 1921 57.87 1922 53.13 1923 57.60 1924 45.07 1925 55.40 1926 58,13 1927 1928 53.80
The distribution of straw in the chief wheat-producing regions of the United States is shown in Table I1 as average figures for the period 1921 to 1924, inclusive (23). Thtl first group of six states, producing 43 per cent of the average annual wheat crop during the four years for which data were taken, shows an average of more than 50 tons of straw per square mile. The second group of five states, with 22 per cent of the wheat production for the peyiod, shows straw concentrations of from 25 to 50 tons per square mile. The third group of seven states produced 21 per cent of the wheat for the four-year period, but shows straw concentrations below 25 tons per square mile. The remaining thirty states, not listed, produce but 14 per cent of the wheat crop, and in general show area concentrations of small magnitude. The figures for straw concentration given in Table I1 can 1
Received January 14, 1930
only be regarded as indicative, since they are based on area units of whole states, and great variation in concentration may occur within each state, depending upon terrain and distribution of industries. In the absence of available data for smaller units of area, these figures, do, however, g k e a general indication of those states in which utilization of btranmay be considered most practicable. While other factors enter into the utilization of farm wastes, the problem of collection of these wastes is the controlling one. The problem of collection in turn is largely dependent upon the area coiicentration of the waste material in connection with such factorb, as method of crop harvesting, available transportation facilities by road and rail, and the cost of baling and transfer froin farm to mill. T a b l e 11-Average Available S t r a w a n d Average Area C o n c e n t r a t i o n of S t r a w in Chief W h e a t - P r o d u c l n g S t a t e s for t h e Years 1921 t o 1924. Inclusive Av . ANNUAL Av. AREA WHEAT AVAILABLE CONCW. STATE PRODUCTION AREA STRAW OF STRAW Million bushels So. miles Million lons Tons/sa. , - mile Kansas 82,080 8.27 124 101.0 North Dakota i8 70,795 5.20 73.5 Oklahoma 43 39,030 2.86 73.2 Illinois 50 56,650 58,7 3.33 Ohio 41,060 56.8 35 2.33 Indiana 29 36,350 1.93 53.1 Nebraska Washington Pennsylvania Missouri South Dakota
52 44 23 33 32
77,510 69,180 45,215 69,415 77,650
3.46 2.93 1.53 2.20 2.13
44.6 42.3 33,s
Colorado Minnesota Montana Idaho Michigan Oregon Texas
21 28 46 24
58,915 83,365 146,080 84,800 58,915 96,030 265,780
1.40 1.86 3.06 1.60
23.8 22.3 20 9 18.9 18.2 14.6 4 5
16 21
18
1.07 1.40 1.20
31.1 27.4
Attempts at Utilization of Straws
Barring the primitive use of straw for the thatching of hut.. a practice retained to the present day among the peaqant classes of civilized races, and also neglecting the early indubtrial use of straw indicated by the complaint of the Israelites
