The Journal of Industrial and Engineering Ghemistry
Published by T H E AM ERICAN CHEM ICAL SO C IE T Y
AT BASTON, PA.
Volume VII M A R C H , 1915 No. 3
BOARD OF EDITORS Editor: M . C. W h i t a k e r
Assistant Editor: L e o l a E. M a r r s
Associate Editors: G. P. Adamson, E. G. Bailey, H. E . Barnard, G. E . Barton, A. V. Bleininger, Wm. Blum, Wm. Brady, C. A. Browne, F. K . Cameron, Wm. Campbell, P. B. Carpenter, C. E . Caspari, V . Coblentz, W. C. Geer, W. F. Hillebrand, W. D. Horne, T . Kamoi, A. D. Little, C. E . Lucke, P . C. M cllhinejj____^
J . M. Matthews, T. J . Parker, J . D. Pennock, Clifford Richardson, W. D. Richardson, G. C. Sto ^^L JO /N...
P u b lish ed m o n th ly . S u b sc rip tio n price to non-m em bers of th e A m erican C hem ical S o ciety , $6.00 y early- \ F o reig n p o stag e, sev en ty -fiv e cen ts, C an a d a , C u b » a n d M exico excepted.
E n te re d as Second-class M a tt e r D ecem b er 19, 1908, a t th e Post-O ffice a t E a s to n , P a ., u n d e r th e A c t of M a rc h 3, 1879.
'K
C ontributions sh ou ld be addressed to M. C. W hitaker, Columbia U n iv ersity , N ew York City
C om m unications co n cern in g ad v ertisem en ts sh ou ld be se n t to T h e A m erican C h em ical S o c ie ty , 42 W est 39th St., N ew York City S u b scrip tions and c la im s lo r lo st c o p ie s sh ou ld be relerr etfto Charles L. P arson s, B ox 5 05, W ashington, D. C.
Es c h e n b a c h Pr i n t i n g Co m p a n y, Ea s t o n. Pa.
T A B L E OF Ed ito rials:
International Engineering Congress... 176
A Statistical Review of the Question of Gasoline Supply 176 Why Not a Chemical Show?... 179
Original Pa p e r s: The Preparation of Gasoline and Kerosene from Heavier Hydrocarbons. B y Benjamin T. Brooks, Raymond I'. Bacon, Fred W. Padgett and Irvin W. Humphrey. 180 The Analytical Distillation of Petroleum. B y W. F. Rittman and E . W. Dean... .. 185
The Germicidal Efficiency of Dental Cements. B y Paul Poetschke... 195
Drying Properties of Linseed Oil Treated with Cobalt, Lead and Manganese Elaeostearates. B y Louis E. Wise and Robert A. Duncan... 202
Variations of the Physical Characteristics of a Petro leum Residuum with Increasing Percentages of Grahamite. B y H. Rossbacher...: ... 205
Investigations on the Oil of Eucalyptus globulus of California. B y Charles E . Burke and Charles C. Scalione... 206
The Separation of Gases by Fractional Distillation in a Vacuum at Low Temperatures. B y G. A. Burrell and I. W. Robertson... 209
A Rapid Method of Fractionating Gases at Low' Tem peratures. B y G. A. Burrell and I. W. Robertson. .. 210
Rapid Analysis of Alloys for Tin, Antimony and Arsenic. B y F. A. Stief... 2 11 Determination of Copper in Steel. B y W. D. Brown. . 213
Recovery of Molybdic Acid. B y W. D. Brow n 213 The Modification of Starch by Gaseous Hydrochloric Acid. B y Francis C. Frary and Arthur C. D ennis.. 214
The Direct and the Invert Polarization of Pure Sucrose. B y Herbert S. Walker... 216
The Nitrogen and Fat in Short Staple Cottonseed. B y C. A. Wells and F. H. Smith... 217
Unsaponifiable M atter in Greases. B y E. Twitchell. . . 217
A New Method for the Determination of the Total F atty Acids and Other Ether-Soluble Constituents of Feedstuffs. B y J . B. Rather... 218
A Chemical Study of Two Drought-Resisting Forage Plants. B y S. Lomanitz... 220
The Determination of Ammonia in Soils. B y R. S. Potter and R. S. Snyder... 221
The Determination of Soil Carbonates—A Modification. B y W. H. Maclntire and L. G. Willis... 227,
The Chemistry of Base Goods Fertilizer. B y Elbert C. Lathrop... 228
C O N T E N T S La bo r a to r yand Pla n t : Purification and Sterilization of Air. B y S. Born and Wm. F . C arth aus... 233
An Eth er R ecovery Tube. B y J . M . P ick e l... 236
A Convenient Form of Weighing Pipette. B y A . T . M ertes... 236
A Filter-Pipette for Ether. B y J . M . P ick e l... 236
Ad d r e s s e s: The D yestuff Situation and Its Lesson. B y A rthur D. L ittle ... .. 237
The New Knowledge of Coal and Its Practical A pplica tion. B y Horace C. P o rter... 239
Pe r k in Me d a l Aw ard : Introductory Address. B y G. W. T hom pson... 243
Presentation Address. B y C. F . C handler... 243
Edw ard Weston’s Inventions. B y L . H . B aek elan d . . . 244
Address of Acceptance. B y Edw ard W eston... 248
Some of Dr. Edw ard W eston’s Achievem ents in the Field of Electricity. B y C arl H erin g... 253
: Cu r r e n t In d u st r ia l Ne w s: Safety Engineering... 254
Liquid Air in In d u stry... 255
Aluminum in the G as In d u stry... 25s Life of Treated Railroad T ie s ... 236
Theory of the Coking Process... 256
Coal, Coke, and Residuals M arkets in G erm an y 256 Coke-Oven Gas for B altim ore... 257
Labor Conditions in E n g la n d ... 257
Gasoline Substitutes... 257
No tesand Co rr espo n d en ce : Note 011 the N ew berry R ap id Lim e D eterm in ation .. . . 258
Prelim inary Note on Artificial Zeolite— P e r m u tit 259 Petroleum Exh ibit— San Francisco, Panam a-Pacific International Exp osition... 259
Fiftieth M eeting of American Chemical Society, New Orleans, M arch 3 1 to April 3, 1 9 1 5 ... 260
The Use of H ydrom etallurgical Apparatus in Chemical Engineering— A C orrection... 261
Pe r so n a l No t e s... 261
Go vern m en t Pu b l ic a t io n s... 262
Book Re v ie w s: Liquid Fuels: Die Flüssigen Brennstoffe (Ihre Bedeut ung und Beschaffung); W ater Supplies,Their Purifica tion, Filtration and Sterilization. A Handbook for the Use of Local and M unicipal Authorities; Clean W ater and How to G et I t ; A ssaying in T h eory and P ractice... 266
Ne w Pu b l ic a t io n s ... 267
Re c e n t In v e n t io n s... 269
Ma r k e t Re p o r t... 270
EDITORIALS
INTERNATIO NAL EN G IN EER IN G CO N GRESS The 1 dates for the great International Engineering Congress to be held in San Francisco during the Panama-Pacific Exposition have been definitely an
nounced as September 20-25 by W. P. Durand, Chair
man of the Committee of Management. The Congress is to be held under the auspices of the American Society of Civil Engineers, the American Institute of Mining Engineers, the American Society of Mechanical Engineers, the American Institute of Electrical E n gineers and the Society of N aval Architects and Marine Engineers. Colonel G. W. Goethals has consented to act as Honorary President and is ex
pected to preside in person over its general sessions.
The papers to be presented before the Congress will cover the general field of engineering. They are intended to treat the various topics in a broad and comprehensive manner and with special reference to the important lines of progress during the past decade, the present most approved practices and the lines of present and future development. It is in
tended, furthermore, that all such papers shall be accompanied with a reasonably full bibliography of the subject, giving references to the important original papers and sources of information relating to the special topic of the paper. The authors of the papers are distributed over the engineering world, and comprise men eminent in the various branches of the pro-
ession.
A special effort will be made to procure discussions, carefully prepared in advance, for presentation with the papers. In addition, opportunity will be afforded for oral discussion at the various sessions of the Con
gress. It is anticipated that limitations of space may require the ultimate publication of all discussions in condensed or summary form. Discussions will be welcomed in any language at the choice of the writer, and if in other than English will be translated for publication.
The various papers, some 300 or more in number, will be presented before the Congress in 10 or more sections closely approximating the division of subjects by volumes.
The meetings will be held in the new Auditorium building in the Civic Center of San Francisco, in which the Panam a-Pacific International Exposition authori
ties have reserved for the week of the Congress a sufficient number of assembly, section and committee rooms to fully meet all requirements of the Con
gress.
Subject to necessary modification, the transactions will be published in 10 volumes, 6 X 9 inches in size, and of about 500 pages each, with one smaller or half volume which will contain the reports of the general or business meetings of the Congress, together with a title and author index and a brief digest of each paper presented.
The schedule of volumes is as "follows:
Vo l u m e I — Th e Pa n a m a Ca n a l ( 2 4 t o p ic s) Vo l u m e I I — Wa t e r w a y s (6 t o p i c s)
Ir r ig a t io n (11 t o p ic s) Vo l u m e I I I — Ra i l w a y s (7 t o p ic s)
Vo l u m e I V — Mu n i c i p a l En g i n e e r i n g ( 8 t o p ic s)
Vo l u m e V — Ma t e r i a l so f En g i n e e r i n g Co n s t r u c t i o n ( 2 0 t o p i c s) Vo l u m e s V I a n d V I I — Me c h a n i c a l En g i n e e r i n g ( 2 8 t o p i c s)
El e c t r ic a l En g i n e e r i n g ( 8 t o p i c s) Vo l u m e V I I I— Mi n i n g En g i n e e r i n g (10 t o p i c s)
Me t a l l u r g y ( 1 0 t o p i c s)
Vo l u m e I X — Na v a l Ar c h i t e c t u r e a n d Ma r i n e En g i n e e r i n g (1 9 t o p ic s)
Vo l u m e X — Mi s c e l l a n e o u s In d e xa n d Di g e s t
All engineers and all others who are interested in engineering work, its progress and achievements, are cordially invited to subscribe as members of the Con
gress.
The general fee for membership in the Congress, open to all engineers or others interested in engineering subjects, is $s-oo U. S. Gold, which will entitle the member to receive the index volume and any single volume of the transactions he may select, together with the right of participation in all general activities and privileges of the Congress.
It is expected that there will be arranged a number of excursions to points of engineering and general interest within practicable reach of San Francisco, and every effort will be made to make possible the personal inspection of such engineering works as are especially typical of the Pacific Coast.
A STATISTICAL REVIEW OF T H E QUESTION OF GASO LINE SU PPLY
Some three or four years ago the question of an ade
quate supply of gasoline threatened to become acute.
This situation was brought about by causes the most important of which are familiar to all interested in petroleum. During the brief period of the last three years a large number of patents have appeared, which have for their object the increasing of the yield of gasoline, some of them constituting real advances in petroleum technology and others interesting be
cause of the bizarre transformation which matter, in the form of petroleum, is made to undergo. The situation just prior to the introduction of improved methods of cracking is here briefly reviewed.
Reliable statistics of the production of gasoline are not available, particularly in this country, the largest producer up to the present time. A better index of available gasoline is obtained by reference to the crudes which yield it. The world’s production of petroleum since 1900 is graphically shown in Fig.
I. Attention should be called to the fact that the greatest increases in the production of crude have been in fields yielding heavy oil containing little or no gaso
line, as is the case with California and Mexican oils.
Arnold and Garfias {Bull. Am. Inst. M in. Eng., 1914, p. 394) place the probable maximum annual production of California at about 100,000,000 barrels. Rear Admiral Edwards (Bull. Am. Inst. M in. Eng., 1914, p. 2293) has recently expressed a similar opinion. On
M ar., 1 9 1 5 T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 177 the other hand, some of the fields yielding oil contain
ing relatively large percentages of gasoline have sharply declined, as the Appalachian and Lim a-Indiana fields, or have remained practically stationary as has been the case with Russia and the Dutch E ast Indies.
This is indicated in Fig. I. The curve designated as
350 300 250 200 150 JÛO
5 0
F /g- I - Pe t r o l e u m Pr o d u c t i o n ,
S / M C E 1 9 0 0 y
/
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Si
/
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u s j. L tq jlt C ru o (es
R u s s i a &
1
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I n d i i?s
/ 3 0 0 ¡ 9 0 2 1 9 0 4 / 9 0 6 / 9 0 B ' 1 3 1 0 / 9 / Z / 9 / 3
“ U. S. Light Crudes” gives the production in the various fields of the United States With the exception of California and the Gulf, since these latter fields can hardly be considered factors in the production of natural gasoline. While small yields of gasoline are obtainable from some of the Californian, Mexican, and Gulf oils, it is also true that small pools of very heavy oils occur in fields classed in Fig. I as “ Light Crudes.” It is believed that these factors fairly bal
ance, making the classification used a rational one.
The relative insignificance of foreign sources, such as the Dutch E ast Indies, is apparent. In this connec
tion it may be of interest to note the production of petroleum in the four principal Baku districts during the last four years.
Pr o d u c t i o n o f Pe t r o l e u m i n t h e Pr i n c i p a l Ba k u Dis t r i c t s
Y e ar T o n s P rice p er to n
O cto b er 1909 to O ctober 1 9 1 0 ... . 8,766,000 $ 4 .4 8 O cto b er 1910 to O ctober 1911... 7,819,200 5 .3 0 O cto b er 1911 to O ctober 1912... 7,470,000 8 .7 4 O cto b er 1912 to O ctober 1913... 7,192,000 11.38
The effect on production of increase in the prices paid for light crudes during 19 12 and 19 13 was very slight indeed, an actual decrease in the total produc
tion of light crudes in the United States having oc
curred, as is shown in Fig. I. (The figures for 19 14 , including the Cushing pool, are not yet available.)
Av e r a g e Pr ic e o f Lig h t Cr u d e s Pe r Ba r r e l i n U . S. Fi e l d s
Y e ar P en n a. 11 1. O kla. T ex as
1910... ... S i . 33 $ 0 .5 9 $ 0 .3 9 $ 0 .7 5 1911... ... 1.30 0 .6 3 0 .4 8 0 . 6 6 1912... ... 1 .64 0 .8 5 0 .6 7 0 .7 5 1913 A u g u st... ... 2 .5 0 1.3 0 1 .03 0 .9 0 1914 J a n u a r y ... ... 2 .5 0 1.45 1.05 0 .9 5 1914 D e ce m b e r... ... 1 .50 0 .8 9 0 .5 5 0 .5 5
gasoline has undoubtedly been a big factor in the general increase in prices paid for light crudes. This is indicated by the fact that the oils richest in gasoline showed the greatest advances in price. The gasoline consumption in England, a non-producing country, has been taken as probably indicating most accurately the new conditions confronting the market.
This rapid increase has been due chiefly to the auto
mobile, motor cycle and motor boat. The number of automobiles in England increased from 276,258 in 1 9 11 to 440,000 in 19 13 . Even more remarkable is the increase in the number of automobiles in use in the United States. In 19 10 there were in the United States, as nearly as can be ascertained, from the regis
tration statistics, about 350,000 motor vehicles in use;
in 19 1 1 the figure given was 550,000, in 19 12 this total had mounted to 990,700, and is estimated at the pres
ent time at 1,500,000. (New York Journal Comm., Aug. 8, 1914).
The number of makers of commercial trucks in
creased from 198 in 1 9 1 1 , to 3 12 in 19 12 , and there are now stated to be 85,000 motor vehicles in this class in operation in this country. The rapid increase in the use of motor trucks during the last two years is of the greatest importance, because of the demand for a cheaper grade of gasoline or motor fuel. More ac
curate data arc available giving the number of auto
mobiles manufactured in this country since 1903.
This is shown graphically in Fig. III.
Evidently the demand for gasoline has been growing at a much greater rate than the production. There are other factors which tend to make higher prices for crude petroleums of practically all classes. The
00
7 0
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SO
4 0
3 0
20
F l G - J L — C O N S U M P T I O N O F G A S O L I N E i n E n g l a n d s / n c e / 3 0 5
/
1 /
7
f
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1905 '06 '07 '00 '09 '10 ’II '!Z 13
The tremendous increase in the consumption of
consumption of fuel oil in this country for steaming purposes has doubled since 1906, although its market price has approximately doubled in the same period.
[Arnold and Garfias {Bull.- Am. Inst. M in. Eng., 1914, p. 394) call attention to the fact that, considering only the relative heating value and market prices of fuel oil and coal in California, fuel oil should sell for
$0 .9 3 per bbl. The consumption of oil for fuel in this country in 1906 was is ,5 7 7 > °°° bbls. and in 19 13 was 33,004,000 bbls.] The production of asphalt from residuum increased 33. 7 per cent during the year 19 12, the total production amounting to 3 3 3 ,2 13 tons.
A critical examination of the various ways of meet
ing a possible shortage of gasoline brings out only more strongly the paramount importance of a plenti
ful supply of this article.
In general, the gasoline now on the market aver
ages ten degrees Baumé lower gravity than the com
mon market product of only a few years ago. Users of automobiles have found that in most motor vehi
cles the heavier grades of gasoline are perfectly satis
factory. As expressed by V. B. Lewes in the Journal of the Royal Society of Arts, 1913, p. 706: “ for con
tinuous running, with the engine hot, such mixtures of petrol and kerosene give excellent results, showing indeed, an improvement in power over the original spirit.” Numerous attempts have been made to de
vise carbureters to use oil of about 48 o Bé., but none has as yet come into wide use. Most of them give difficulty in starting, and the engine does not pick up if allowed to slow down. One type of carbureter
f í e 504000
■ M - Number o r Au t o m o b il e s Ma n u fac tu r e d
i nthe Un it e d St a t e s /
400,000 /
'ICOJOi /
z o m a /
M000-
1303 '04 ‘0 5 '06 ‘0 7 ‘03 '09 '/O 'II 'U ’/3
now being advocated is arranged to be started on gasoline and, after the engine is hot, uses kerosene of about 46° B6. without trouble, but the day of the kerosene motor has not yet arrived, and whether motor fuel heavier than about 55° B6. will ever give satisfaction in automobile engines is very doubtful.
The gravity alone does not necessarily indicate what an oil will do in a gasoline engine. The volatility of an oil and the temperature at which it w ill form explosion mixtures are of greater importance than gravity. As indicated above, the motor fuel now in common use is considerably heavier than that sold a few years ago. It should be remembered that the character of “ gasoline” was originally determined by the flash point limits prescribed by law for kerosene and had no reference to the adaptability of the gasoline for internal combustion engines. While considera
ble work has been done in attempting to utilize kero
sene in automobiles apparently no system atic, im
partial investigation has ever been made to determine how much of the lighter fractions of kerosene can be included in the various grades of light gasoline for good results with the carbureters and gasoline motors now in common use. The gasoline of the present
day may be considered as that fraction boiling under approxim ately 15 0 ° C. It should be pointed out that if the whole distillate boiling below 200° C., which would include approxim ately a third of the kerosene, could be used as motor fuel, the quantity of the latter available would be doubled. Such motor fuel would have a gravity of approxim ately 56° Bé.
The manufacturer of casing-head gasoline is in
creasing the production slightly, but the maximum production from this source is small, probably not more than a million barrels annually. The United States Geological Survey gives the production of natural gas gasoline in this country in 19 13 as 571,000 barrels of 42 gallons. Singer, in Petroleum, 9 (19 13 ), 453, gives the U. S. production in 19 12 as 12,- 081.000 gallons or about 287,000 barrels. Y et if 1,500,- 000 automobiles use 10 barrels each per year we ar
rive at a grand total gasoline consumption of 15, 000,000 barrels in this country for automobiles alone.
Casing-head gasoline cannot therefore meet more than a small fraction of the requirement. Not all of this will be available for motor purposes, as special uses for it have already been found. The methods which have been suggested for the recovery of similar prod
ucts are of only very minor importance, such as the condensation of the gases from petroleum stills, which ordinarily escape uncondensed. Groeling (D. R . P., 246)935 of 1909) absorbs the uncondensed vapors by passing them through naphtha. Blau (U. S. Pat.
994,369 of 19 11) subjects oil gas to pressure and sepa
rates a low boiling gasoline. Wolff (U. S. Pat. 1,000,655 of 19 11) liquefies a similar product by the Lindé effect.
The production of shale oil cannot, at present, be considered a factor. Sir Boverton Redwood (/.
Roy. Soc. Arts., Dec. 26, 19 13) claims that motor fuel from Scotch shale oil contributed last year only 0 .7 5 per cent of England’s consumption of motor fuel.
The shale oil industry appears to be in a static condi
tion, the production in 19 13 having been only 3 per cent greater than in 1904.
Benzol, from coal tar, has found some favor in Europe for motor vehicles, but the largest possible supply is very small compared with the requirements. In 19 12 England consumed 80,000,000 gallons of gasoline and produced 8,000,000 gallons of crude benzol (/.
Soc. Chem. Ind., 1913, 514), most of which was ex
ported for use in other industries. The coal coked in by-product ovens in the United States in 19 13 was approximately 17,000,000 tons, according to the esti
mate of H. C. Porter in the U. S. Bureau of Mines Technologic Paper, No. 89. Mr. Porter estimates the possible production of benzol from this source at about 600,000 barrels (of 42 gallons). There were actually produced, in 19 13 , about 190,000 barrels by passing the gas through heavy oil, and “ possibly 24.000 barrels more by tar distillation. Much of this, about one-half, was used in enriching gas for illumina
ting purposes.” The use of by-product ovens is in
creasing but, on the other hand, oil-gas and oil pro- ducer-gas plants are rapidly displacing the coal re
tort, as the consumption of 13,800,000 barrels of oil in 1909 for gas making in this country show. Data
M ar., 19x5 T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 179 on the possible production of benzol from oil-gas tar
are not available.
Benzol has been recommended as a valuable addition to alcohol for motor purposes. Alcohol, as a motor fuel, has received considerable attention. Although 95 per cent alcohol has little more than half the calorific value of gasoline of 0 . 7 1 0 specific gravity (58 33 C.
as compared with 1 0 6 1 1 C.), it gives a relatively higher efficiency, owing to its greater ease of combus
tion, smaller proportion of air required for complete combustion, and greater compression with a slightly cooler cycle. It is possible that engines will be perfected which will be better adapted to alcohol than the pres
ent gasoline motor. However, industrial denatured alcohol has failed to reach the low prices predicted for it. It is now quoted at 37 cents per gallon, and for the same results in a gasoline motor, would be at least 20 per cent more costly than gasoline at 40 cents per gallon. It is significant that denatured alcohol has not heretofore been used as motor fuel in England even when gasoline sold for 38 to 42 cents per gallon.
Ormandy (Zeitschr. f. angew. Chem., i9 r4i Ref. 1 77 ) has recently published the following results of tests made with different mixtures of alcohol and benzol.
[Cf. M oyer, Power, 1914, p. 569].
Mo t o r Te s t s w i t h Di f f e r e n t Mi x t u r e s o f Al c o h o l a n d Be n z o l Pe r Ce n t Re s u l t s Co m p a r e d w i t h Ga s o l i n e St a n d a r d A l c o h o l B e n z o l P o w e r F u e l c o n s u m p t i o n
5 0 5.0 1 p e r c e n t l e s s 3 p e r c e n t le s s 6 6 . 7 3 3 . 3 8 p e r c e n t l e s s 8 . 9 p e r c e n t g r e a te r 7 5 2 5 8 . 5 p e r c e n t l e s s 2 4 . 5 p e r c e n t g r e a te r
So far, all attempts to adapt the heavy oil engines of the Diesel type to motor vehicles have failed.
It seems certain, therefore, that gasoline, including the lighter part of kerosene, is for motor vehicles the undisputed necessity of the day, and that there is nothing seriously to compete with it so long as its retail cost does not exceed about 40 cents per gallon, at which figure alcohol may possibly become a com
petitor. Redwood and Lewes regard the eventual employment of alcohol as a motor fuel as inevitable [Cltem. Abs., 7 ( 1 9 1 3 ) , 3 4 1 0 ; Redwood, J . Roy. Soc.
Arts, Dec. 26, 1 9 1 3 ] . Estim ating the present pro
duction of gasoline in this country as 25,000,000 barrels of 42 gallons each, the amount of corn required to produce the same volume of 96 per cent alcohol by fer
mentation would be approximately 450,000,000 bushels, an amount certain to affect prices to a marked degree, in view of the fact that we have no corn for export.
Increasing the available supply of gasoline by crack
ing, particularly by distilling under pressure, has long been known to' be a possibility; in fact Dewar and Redwood patented such a process twenty years ago, but with the object of manufacturing illuminating oil, not gasoline.
B e n j a m i n T. B r o o k s
WHY NOT A CHEMICAL SHOW?
It has often been said that of all professional work the chemist’s is least known to the general public.
The bar is known more or less through the press, the clergy through the pulpit, the physician meets all classes in the course of his work, and to the architect and the engineer Sir Christopher Wren’s epitaph
applies, “ S i monumcntum requiris, circumspice”— if you seek his monument, look about you. The chem
ist’s work is done chiefly in his laboratory out of sight of the public, and it is largely, though vital, only contributory; that is, except in the case of those in
dustries of a purely chemical nature, such as the manu
facture of chemicals, the chemist’s contribution is often absorbed in a larger whole, as for example in the steel industry, and thus lost to the view of all except those who have an intimate knowledge of the circum
stances. These, and not the chemist’s native mod
esty, are probably the chief reasons for the average man’s lack of fam iliarity with the field of applied chemistry.
This is a condition, however, that is continually changing. People in general are much better in
formed in technical matters now than they were a great many years ago, and this information is con
tinually spreading. The recent crisis in this country brought on by the war has brought home more defi
nitely than ever before the value of the chemist in industry, while at the same time, in spite of the spread of information, it has shown more clearly than ever before, as for example in newspaper discussions of the dye situation, how little appreciation there is of the enormous development chemistry has undergone and the time this development has required.
A time like this, then, would seem particularly pro
pitious for any undertaking that would crystallize out in the minds of the public the knowledge already present in a more or less amorphous shape of what chemistry today means, and at the same time add a large amount of new information of the same kind.
Such an undertaking would be of reciprocal benefit to the public and the chemical profession.
The most direct agency of that kind would be an exhibition modeled after the electrical and gas shows and many others of the same kind held in New York annually. It ought to draw the public, for it would not only be a novelty but would contain exhibits fully as spectacular, interesting and instructive as those of other shows. It ought to draw the support of manufacturers of chemicals, chemical products, chemical apparatus and related products, because it would offer unusual advertising facilities. It ought to have behind it the whole profession because it would broaden and stimulate interest in chemistry and ap
preciation of its value.
It is not possible here to go into the number or kind of exhibits that could be placed on view, but the possi
bilities are so great that it would probably be more necessary to limit the field than to seek to enlarge it.
Against the scheme may be presented the facts that it would be an experiment, that it would be expensive, and that to carry it out some new organization would probably have to be formed. The only answer to these points would be some general expression of opinion of those interested, particularly those likely to become exhibitors. _
M a r s t o n L. H a m l i n
ORIGINAL PAPERS
T H E PREPARATIO N OF GASOLINE AND K E R O SE N E FRO M H EA V IER HYDROCARBONS
B y Be n j a m i n T . Br o o k s, Ra y m o n d F . Ba c o n, Fr e d W . Pa d g e t t a n d Ir v i n W . Hu m p h r e y
R eceived J a n u a ry 21, 1915
The earlier attempts to convert heavy petroleum hydrocarbons of high boiling points into lighter more volatile products were carried out in most, if not all, cases with the object of increasing the yield of illumina
ting oil.
The "cra ck in g ” of heavy hydrocarbons by heat is to be regarded as simply an instance of the general rule that organic compounds are decomposed by heat.
It is well known that the simpler petroleum hydrocar
bons are stable at much higher temperatures than those of higher molecular weight. E ve ry refiner knows that certain crudes “ crack” more easily than others, which fact is to be accounted for by the pres
ence of hydrocarbons of different constitution. In the case of the simpler hydrocarbons which have been studied, it is known that defines are in general less stable to heat than saturated hydrocarbons of the same molecular weight, and naphthenes are usually more stable than paraffines. Normal hexane and the more stable methyl cyclopentane are good examples of the latter types. It was to be expected, therefore, that attempts would be made to produce gasoline from heavier hydrocarbons by heat decomposition at temperatures somewhat higher than those employed for the production of kerosene by cracking. A large number of recent patents seek to attain this end.
The fatal difficulty with processes of this class, opera
ting at atmospheric pressure, is the large per cent of defines contained in the resulting gasoline. This figure will vary, when the oil is simply subjected to heat at atmospheric pressure, from 20 to 50 per cent, depend
ing on the temperature at which the oil is cracked.
The maximum per cent of defines demanded by the simple general equation, RCH2 — CHs — CH2R1 — >- R C H 3 + CH 2 = C H .R i, is seldom attained owing to other reactions, such as polymerization of the defines and the formation of naphthenes. Gaso
line made by cracking under atmospheric pressure, the heavier portion of Oklahoma crude, i. e., the part left after distilling off the gasoline and kero
sene, in such a way as to condense and return to the $till all but gasoline and naphtha, showed a content of olefines of approxim ately 28 per cent, as indicated by the iodine number and loss to ordinary sulfuric acid. Consequently a number of patents have been issued covering processes which seek to hydrogenate the olefines formed. It has been pro
posed1 to hydrogenate the olefines by placing a catalyst, such as platinum or palladium, in the still, but this process is not being operated for obvious reasons.
Several proposed processes claim the cracking of heavy hydrocarbons in the presence of steam and iron. The method patented by the New Oil Refining Process
1 U. S. P a te n t 826.089, Ju ly 17, 1906.
Company, L td .,1 requires the passing of petroleum and steam through a retort containing scrap iron at 540° to 650° C. The processes proposed by Adam s,2 Greenstreet,3 Hyndm an,4 and Turner6 specify the cracking of heavy oil at higher temperatures (Green
street and Hyndman specify a “ cherry tem perature” ) in the presence of steam alone. The claim has been made that the water is converted into CO and hydro
gen, the latter effecting hydrogenation of the olefines produced. Testelin and Renard6 vary this by passing the vapors of oil and steam over a red-hot layer of clay or alumina. Vernon Boys7 passes the oil and steam mixture through heated tubes containing nickel rods. Lamplough8 cracks in the presence of steam and in contact with nickel in a retort maintained at a dull red heat. Moeller and W oltereck9 pass oil and steam through tubes containing coke at 600 ° to 700° C.
None of the above processes are being operated on a large scale in this country at the present time.
Another method of subjecting the heavy petroleum hydrocarbons to the higher temperatures required to produce the desired increased yields of gasoline is heating or distilling under pressure. It is known that unsaturated hydrocarbons are condensed to saturated hydrocarbons by the action of heat and pressure.
Ipatiew 10 showed that ethylene, probably the most stable of the olefines, could be converted into a mix
ture of liquid hydrocarbons at 3 2 5 0 C. and 70 atmos- spheres pressure. At 380° to 4000 C. the reaction was sufficiently rapid to cause a fall of 5 atmospheres per minute in the pressure of the closed apparatus.
Engler11 and his collaborators have shown that amylene and hexylene yield saturated compounds of the naph- thene type by heating under pressure. It is therefore to be expected that naphthenes will be found in gaso
line and kerosene made by pressure distillation of heavier hydrocarbons; indeed, this has been shown by Engler.12
In regard to the pressure distillation processes which have been proposed, the older ones sought to increase the yield of kerosene, since gasoline, in the days of such early patents as those of Benton, was of very little value. In the present discussion, only the more important processes are mentioned. In 1S69, Peckham13 claimed to have obtained, by dis
tilling under 20 lbs. pressure, as much as 60 per cent illuminating oil of specific gravity 0 .8 10 from a Cali-
> F ren ch P a te n t 451.471. D ecem ber, 1912; E n g . P a t. 28,460, 1911;
E n g . P a t. 20,074, 20,075, S e p te m b e r 3. 1912; E n g . P a t. 13,675, 1908.
5 Petroleum Gazette, 1910, Ju ly , p. 2.
* U . S. P a te n t 1 ,1 1 0 ,9 2 5 ; E n g lish P a te n t 1 6 ,4 5 2 , J u ly 13 , 1 9 1 2 . 4 F ren c h P a te n t 4 6 2 ,4 8 4 , S e p te m b e r 1 1 , 1 9 1 3 .
» F re n c h P a te n t 4 5 1 ,1 6 2 , 1 9 1 2 .
• G erm an P a te n t 2 6 8 ,1 7 6 , O c to b er 1 2 , 1 9 1 3 . T M et. Client. E ng., 1914, p . 1 80.
» E n g lish P a te n t 1 9 ,7 0 2 , A u g u st 2 8 , 1 9 1 2 . 9 E n g . P a te n t 1 6 ,6 1 1 , Ju ly , 1 9 1 3 .
»« Ber. d. dent. chem. Ges., 44 ( 1 9 1 1 ) , 2 9 7 8 .
“ Ib id ., 42 ( 1 9 0 9 ) , 4 6 1 0 , 4 6 1 3 , 4 6 2 0 ; 43 ( 1 9 1 0 ) , 3 8 8 .
12 E ngler, Ib id ., 33 ( 1 9 0 0 ) , 2 9 1 5 ; N a stju k o ff, J . Russ. P hys. Chem. Ges., 36 ( 1 9 0 4 ) , 8 8 1 ; K ra e m r & S pilker, Ber. d. dent. chem. Ges., 33 ( 1 9 0 0 ) , 2 2 6 5 .
11 Chemical N ew s, 1869, p. 183.
M ar., 1 9 1 5 T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 1 8 1 fornia crude oil yielding 20 per cent kerosene of the
same quality when distilled in the usual manner at atmospheric pressure. Thorpe and Young1 obtained from parafBne, by heating at a “ high pressure” and subsequent fractionation, a light oil shown to contain pentane, hexane, heptane, octane and nonane.
A few patented processes,2-including the recent ones of Testelin and Renard,3 subject oil to heat and pres
sure and distil the liquid after the pressure is released.
Testelin and Renard seek to avoid the deposition of carbon, always obtained when oil or oil vapor is passed through a heated pipe coil, as in some of the earlier processes. This they proposed to do by uniformly heating the pipe coil, containing the liquid oil, to a temperature not exceeding 450° C., by submerging the coil in a bath of lead at the desired temperature.
A sufficient pressure was maintained on the heated
oil to keep it in a liquid state. The process patented by C lark4 describes pumping the oil through heated pipes, collecting the hot oil ip a receiving drum where distillation under pressure is permitted. The older patents of Benton5 also embodied the principle of sub
sequent distillation after release of the pressure but heated the pipe coils directly by a flame.
As regards actual distillation under pressure, a num
ber of early patents describe the manufacture of \Il
luminating oils by the use of low pressures. Thus Young6 stipulated pressures of 10 to 20 pounds per square inch. K rey7 recommended two to four atmos
pheres and claimed to obtain a distillate of a specific gravity of 0 . 8 2 0 (yield not given). Boleg8 recom
mended pressures of three to four atmospheres and says that pressures of four to six atmospheres yield more “ illuminating oil” but less “ lubricating dis
tillate” than the lower pressure. Dewar and Red
wood8 devised an apparatus for distilling petroleum under pressure, which is the general arrangement now employed on a larger scale by a later patentee.
Dewar and Redwood, however, did not state what pressure gave the results desired nor did they advo-
■ Chcm. S e w s . 1 8 7 1 , (23), 124; 1 8 7 2 , (26). 35.
3 ShuchofI and G awryloff, Zcitschr. f . angew. Chem.t 1 8 9 3 , p . 231.
* R en a rd , E n g . P a te n t 3,413, F e b ru a ry 10, 1913.
4 U . S. P a te n t 1,119.496 Dec. 1, 1914.
* U. S. P a te n t 342,564 and 342,565.
* E n g lish P a te n t 3,345, D ecem ber 27, 1865.
7 G erm an P a te n t 37,728 (1886).
*’Chem. Rev., 9 (1898), 24.
» U. S. P a te n t 419,931, 1890; 426,173, 1891; E nglish P a te n t 10.277.
1889; 13,016, 1890; 5,971, 1891.
cate their process as one suitable for manufacturing gasoline.
The foregoing brief review outlines the “ state of the a r t ” prior to the patent of Bacon and C lark.1 The latter patent specifies the distillation of heavy petroleum oils betwee-n pressures of 100 and 300 pounds. The advantages of the range specified, so far as increased yields of gasoline are concerned, are brought out by the results represented graphically in Fig. I I I . The yields given are not the maximum obtainable but represent comparative results of a series of experiments obtained by distilling a given quantity of Oklahoma reduced oil at a uniform rale from the same apparatus at the different pressures indicated.
The effect of pressure in diminishing the per cent of olefines in the gasoline obtained is a noteworthy feature of these results. The same effect is very strikingly shown in the recent results of Whitaker and Rittm an2 on the effect of pressure in the yield of illuminants in oil gas. At 900° C., W hitaker and Rittm an obtained from a given quantity of oil 122 liters of illuminants at 0 .75 lb. pressure, 50 liters at atmospheric pressure and 1 5 .5 liters at 45 lbs. (abso
lute) pressure. They were also able to show that at temperatures of 750° to 8oo° C. the addition of hydro
gen to the gas mixture has the effect of partially hydrogenating the olefines and that this reaction takes place more readily as the pressure on the system is increased. Ipatiew 3 has made the interesting ob
servation that, in the distillation of petroleum under pressure, at the higher pressures the evolved gases become continually poorer in hydrogen in spite of the higher temperatures required to maintain the higher pressures. The pressures employed by Ipatiëw were 120 to 340 atmospheres. We have found the follow
ing:
Ta b l e I — Ga s e s f r o m Cr a c k i n g Di s t i l l a t i o n s u n d e r 1 0 0 Po u n d s Pr e s s u r e’
(o )F ro m Jen n in g s cru d e (6)P araffin e
Sam ple N o . I I I I I I I I I I I I
T e m p e ra tu re in
s t i l l ... 3 4 0 ° C. 4 1 5 ° C. 4 2 2 ° C. 4 1 7 ° C. 4 3 2 ° C. 4 3 7 ° C.
C O j... 1 . 2 0 . 5 0 . 0 0 . 0 0 . 0 0 . 0 C O... 1 . 2 0 . 5 1 . 3 0 . 0 3 7 . 0 3 3 . 5 I llu m in a n ts... 1 5 . 4 1 5 . 3 1 3 . 0 2 5 . 4 0 . 0 0 . 0 H y d ro g e n... 0 . 0 4 . 0 4 . 4 0 . 3 0 . 9 3 . 0 S a tu ra te d h y d ro
c a rb o n s... 8 1 . 5 7 9 . 7 8 1 . 3 7 4 . 3 6 2 . 1 6 3 . 5
The analyses in Table 1(a) were made of the gases evolved during a cracking distillation of a reduced oil prepared by removing from Jennings crude all con
stituents boiling below 265° C. Sample I was taken as soon as 100 pounds pressure had been reached.
Sample II was collected after 40 per cent of the charge had been distilled, and Sample I I I after 75 per cent had distilled.
The liberation of hydrogen from petroleum hydro- . carbons at various temperatures has been studied by Engler4 and his students. They obtained no h y drogen below .470° at atmospheric pressure from kero
sene fractions boiling below 280° C. The liberation of hydrogen from different hydrocarbons at a given
1 U. S. P a te n t 1 ,1 0 1 ,4 8 2 . U n d er I n t . C onv., M a y 6 , 1 9 1 2 . 2 Th i s Jo u r n a l, 6 ( 1 9 1 4 ) , 4 7 9 .
* Ber. d. deut. chcm. Gcs., 3 7 ( 1 9 0 4 ) , 2 9 6 9 . 4 E n g ler a n d H M er, D as E rd d l, 1, 5 7 4 .
temperature depends somewhat on their constitution.
Thus, benzol yields appreciable quantities of hydro
gen only at temperatures above 500° C.
Our work indicates that i f hydrogenation of the liquid defines takes place during distillation under pressure, it occurs simultaneously with their initial formation. A sample ‘of cracked naphtha, having an iodine number of 55.0, was heated to 196° C. with hydrogen for thirty hours under 3,000 lbs. pressure per square inch. The iodine number and refining loss with sulfuric acid were practically unaffected, the iodine number of the final product being 52.9.
Results closely parallel to this were obtained by Mr.
Edmund Rhodes, in this laboratory, working with liquid fatty oils. The apparatus employed was a steel bomb connected with a solenoid stirrer con
structed as described by Stucker and Enduli.1 Uebbelohde and Woronin2 showed that in the pres
ence of nickel, hydrogen was split off from a Baku crude oil at as low a temperature as 18 0 ° C. The re
sults of Zelinski3 with platinum as a catalyst show that
F i o . I I — Ap p a r a t u s Em p l o y e db y De w a ra n d Re d w o o d
dehydrogenation at temperatures above 3000 C. in the presence of platinum is to be expected. Ostromiss- lenski and Bujanadse4 showed that in the presence of nickel a Russian crude oil gave only coke, 40 per cent, and gas at temperatures between 600-700° C., no tar or liquid being obtained at all. Furthermore, the gas contained 72 to 75 per cent of hydrogen and the re
mainder consisted of saturated hydrocarbons. These facts are quite significant in view of the proposed cracking processes of Vernon Boys, Lamplough and others, who introduce nickel into the cracking zone.
A series of experiments were made in this laboratory at atmospheric pressure and at temperatures of 500- 550° C., employing various catalytic substances.
Kerosene and solar oil vapors passed through an iron tube containing burned clay, carbon, coarse and finely divided iron, coarse and finely divided copper, heated to the above-named temperature, yielded gasoline fractions, which showed an olefine content of approxi
mately 25 to 30 per cent. When nickel was em-
* Zritschr. f . Eleklroch., 1 9 1 3 , p . 5 7 0 .
* Petroleum , B erlin, 1 9 1 1 , pp . 7, 9.
* Ber. d. deutscheti chem. Ges.t 1 9 1 2 , pp . 45, 3678.
4 J . R uss, phys.-chem. Ges., 1 9 1 0 , p . 195.
ployed the per cent of defines in the gasoline product was 48 per cent.
t h e e f f e c t o f n i c k e l in increasing the per cent of olefines, when operating at atmospheric pressure, opens up the question of the effect of foreign substances on the polymerization of olefines and the effect thereon of different physical factors. The percentage of olefines indicated in the above figure does not repre
sent the minimum obtainable even without the addi
tion of a “ catalyst.”
The claim is made by Burton1 that by placing the pressure-controlling valve beyond the condenser so as to condense the volatile gasoline vapors produced by distilling heavy petroleum oils under about 75 lbs.
pressure, olefines are not produced, whereas, if the pressure-controlling valve is placed between the still and condenser, olefines are found in the condensate to such an extent as to render the latter process of doubtful commercial utility. The authors felt that if olefines could somehow be squeezed together or polymerized by 75 pounds pressure in a condenser containing cold water, this fact would be an inter
esting contribution to science, but the experiment noted above, in which a cracked petroleum naphtha was heated for thirty hours at 19 6 ° C. under 3,000 lbs. pressure per square inch practically without change (iodine number reduced from 5 5 .0 to 52.9), seemed to render such a reaction as Burton describes improbable.
We accordingly prepared several gallons of gasoline by distilling Oklahoma “ reduced” oil at approximately 80 lbs. pressure, in one case with the valve between the still and the condenser, and in another experiment with the still and condenser in free communication, so as to condense the vapors under pressure, all other conditions remaining the same.
Ga s o l i n e I ' I I
P e r c en t refining loss b y 5 p e r c e n t conc. H*SO<.. . 7 .9 8 .0 P er c e n t refining loss b y 5 p e r c e n t " o le u m " ... 12 .2 12 .0
Ke r o s e n e, boiling p o in t 3 0 2 -3 9 2 ° F .
P e r c e n t refining loss b y 5 p e r c e n t “ o le u m " ... 9 . 0 8 .0
In I the valve was interposed between still and con
denser; and in II the still and condenser were in free communication, control valve being beyond the con
denser. These results indicate that the claim made by Burton concerning the effect on the yield of olefines caused by different positions of the pressure-con- trd lin g valve are unwarranted.
Dewar and Redwood2 specified clearly that they condensed the distillate, obtained in their process, under pressure. In U. S. Patent 726,173, they make the statement: “ For this purpose we arrange a suitable boiler or retort and a condenser in free communica
tion with one another, without interposing any valve between them; but we provide a regulated outlet for condensed liquid from the condenser.” The rem ark
able effect of the position of the valve on the percentage of olefines in the resulting product was evidently over
looked by Dewar and Redwood. However, in view of the fact that it is not common practice to glean our scientific data from the patent literature, this error on the part of Dewar and Redwood is not such a serious
1 U . S. P a te n t 1,049,667. U n d e r I n t. C onv., J u ly 3, 1912.
* Loc. cit.
M ar., 1 9 1 5 T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 183 matter as it might be. Aside from the above noted
discovery as claimed by Burton, it is difficult to find any novelty in his patent. The operating pressures specified by Burton are four to five atmospheres. Boleg1 described distillation under four atmospheres pressure and in 1886 K rey2 published the results obtained by distilling various crude oils, heavy oils and residues
Fi g. I l l —Yi e l d s a n d Re f i n i n g Lo s s e s o f Ga s o l i n e Ob t a i n e d b y Di s t i l l i n g Ok l a h o m a Re d u c e d Oilu n d k r Pr e s s u r e
G asoline *= D istillate below 150° C.
Refining, b y 1/xo volum e co n cen trated HjSO<
under pressures of three to six atmospheres. Engler3 confirmed the claims of K rey but, like Dewar and Redwood, Engler and K rey did not discover the re
markable effect of the position of the pressure-con
trolling valve, as referred to above.
It has been pointed out that the results presented in Fig. I l l do not represent the maximum yields of gasoline or the minimum percentage of defines obtain
able in the gasoline distillates made by distilling under pressure. It is not the purpose of this paper to point out the optimum working conditions of the process.
However, in the patent of Bacon, Brooks and C lark4 it has been shown that the ratio between the volume of the oil heated and the area of the heating surface of the apparatus employed is an important factor.
.This relation may perhaps be more clearly under
stood if it is stated that, other conditions remaining the same, cracking does not occur throughout the mass of heated oil, but that the cracking effect produced in a given quantity, in a given time, will, vuithin certain limits, be approximately proportional to the heated sur
face in contact with llie oil. It is obvious that distilling slowly will have approximately the same effect as in
creasing the relative area of heated surface. An
other fact brought out in this process is that the depo
sition of coke on vertical heating surfaces is very much less, one-third to one-fifth of the amount deposited on the upper side of a horizontal surface, such as an ordinary still bottom, in a given length of time.
Under higher pressures, such as 200 lbs. per square inch, oils having boiling points above 300° are almost completely prevented from distilling at the mean tem
peratures in the still, i. e., 370° to 420° C.
Laing,5 operating at much lower pressures, attempts to return the heavier boiling fractions of the distillate
1 Chem. Rev. d. Fetl- u. H arz In d ., 1 8 9 8 , pp . 9, 24.
* G erm an P a te n t 37,728 (1886).
* Ber. d. deuischen chem. Ges.. 30 (1897), 2919.
4 U . S. P a te n t Ser. N o. 764,982— Allowed N o v . 24, 1914. U n d er I n t.
C onv., M a y 2, 1913. T o issue M arch 9 , 1915.
* G erm an P a te n t 260,858. O ctober, 1911; Chem. Ztg., 1 9 1 3 , p. 375.
to the still by employing an apparatus such as is shown in Fig. IV.
Although hydrocarbons of the type contained in gasoline are more stable than the heavy hydrocarbons such as are contained in “ reduced” oils, it is never
theless important to remove the gasoline from the
“ sphere of reaction” as fast as formed. Thus, heating a certain volume of heavy oil under a given pressure for a given period of time and subsequently distilling at atmospheric pressure does not yield nearly as much gasoline as distillation under the same pressure, thus removing the gasoline and kerosene as fast as formed.
This was well shown by an experiment in which Oklahoma “ reduced” oil was heated under a pressure of 180 lbs. per square inch for two hours and then dis
tilled at atmospheric pressure. There was obtained in this way only 5 per cent of gasoline, while another experiment under the same conditions, except that the gasoline was distilled as fast as formed, yielded 30 .4 per cent gasoline. This indicates that the gaso
line hydrocarbons themselves slowly decompose in the cracking still. In view of this fact, it is all the more remarkable that the kerosene fractions of the pressure distillate obtained from Oklahoma reduced oil by distilling inder 100 lbs. pressure are optically active.
O P T IC A L A C T IV IT Y O F K E R O S E N E H Y D R O C A R B O N S M A D E BY C R A C K IN G H E A V IE R H Y D R O C A R B O N S
The kerosene fractions of most crudes show very little, if any, optical activity. The maximum rota
tions are noticed in the fractions boiling from about 230° to 290° C. under 12 to 14 mm. pressure. A Galician oil studied by Engler yielded a fraction boil
ing from 200° to 250° under atmospheric pressure, which showed a rotation (200 mm. tube) of + 0 . 2 ° on the saccharimeter scale. The fraction boiling
