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T H E J O U R N A L O F I N D U S T R I A L A N D EATGINEERING C H E M I S T R Y
t h e limit t o which t h e eutectoid is broken up a n d therefore within t h e limit of high distortion. The inner boundary of the layer of recrystallized metal, for 400’ and 6 0 0 ° , is sharp a n d definite. At 800’ this is not so marked; in this case, in making t h e measurements, the maximum depth was chosen. Figs. 4, j , 6 and 7 show the appearance of this outer layer of recrystallization.
*
T‘ol. 8, N o .
2
evident t h a t our process must include some cheap and efficient hydrogenation feature, from which it followed t h a t nascent hydrogen would be desirable. The well known method of producing hydrogen b y passing steam over red-hot chips of iron or steel suggested itself as being feasible. Some modification of this method has been t h e subject of various patents which it is not t h e purpose of the author t o review in this paper. SUMMARY OF RESCLTS Our problem, therefore, resolved itself into two parts: I-The metal, upon annealing, is first brought I-A study of the best conditions for cracking into “ physico-chemical equilibrium.” The dendritic t h e oil. structure persists until heated for approximately 11-The determination of the most favorable conditwo hours a t 800’. T h e absorption of t h e eutectoid depends much upon how the cast sample was cooled tions for saturating with hydrogen, those portions while solidifying; four hours’ heating a t 800’ is re- which were converted into unsaturated compounds. I n all of our work. except as otherwise noted, we quired for its disappearance in those samples which used a n oil obtained under the name of “ Distillates” solidify very slowly. 11--So evidence was found suggesting a change of f r o m the Factory Oil Co., of Akron ( a marketing crystal size of cast samples which had not been dis- concern). Yields were determined by fractionating zoo cc. of t h e product condensed in t h e apparatus, torted in a n y way. through a three-bulb Le Bel-Henninger distilling tube 111-Recrystallization, including “twinning,” was found, only, t o follow distortion; samples which were and collecting t h a t portion which came over below highly strained as a result of very sudden cooling I ; j’ C.; this temperature, which was arbitrary, reprefrom the molten s t a t e behave upon annealing t h e same sented a product averaging 60’ BC. Our apparatus for studying the problem of cracking as those mechanically distorted. Chill castings may consisted of an iron retort holding liters, made b y be expected t o behave in a similar manner. capping a piece of 4-in. standard wrought-iron pipe. 1”-The progress of recrystallization upon annealFrom this retort a piece of I-in. (S. 1%’. I.) pipe 40 in. ing for different periods of time a t t h e same temperalong was passed through a 30-in. combustion furnace ture is in agreement with Tammann’s theory of ret o a condenser, made b y coiling one zo-ft. length of crystallization. TT-Aside from the crystal size and t h e modifica- I-in. (S. TT. I.) pipe, a t t h e outlet of which was placed tion introduced b y “twinning,” t h e end condition of a pressure gauge and finally a valve for regulating material annealed directly after casting and t h a t an- back pressure o n the apparatus. The retort was nealed after a preliminary distortion of the crystal- heated with an ordinary laboratory gas blast lamp. We first studied the effect of distilling the oil and line structure is t h e same in t h e two cases (Figs. condensing under pressure, substantially as described z and 7 ) . b y Burton’s patent.’ Experiments were made disB U R E A C O F S T A N D A R D S . ~ ‘ A S H I N G T O X , D. e. tilling under IO, zj, j o , 7 j and 90 lbs. gauge pressure; the furnace under t h e 40-in. length of pipe was n o t EXPERIMENTS ON THE PRODUCTION OF GASOLINE lighted. Our highest yields gave only about 3 per FROM HYDROCARBON OILS OF HIGH BOILING cent naphtha, determined as above described; we atPOINTS1 tributed the low yields obtained as due t o t h e fact By EARLEI,. DAVIES t h a t a relatively large portion of the oil had distilled Received October 15, 1915 Gasoline is one of the materials used by the rubber over and condensed before t h e desired back pressure industry in fairly large quantities, a n d , since it is, was obtained. The next step was a s t u d y of t h e effect of superused chiefly in cements, etc., which must be dried heating t h e vapors as they passed through the 40-in. entirely free from a n y tarry matter. or similar oily length of pipe. Unfortunately, in this series of exor greasy matter, such ingredients. ex-en in very small amounts, render it unsuitable for use. About the periments, we had no means of measuring t h e temperafirst of t h e year 1913)when these experiments were ture of t h e vapors, b u t t h e tube was kept red-hot and made, t h e price of straight run gasoline n-as extremely was probably heated t o about 600’ t o 650’ C. Rates high and, t o us, t h e prospects for a n y reduction in of distillation, superheat, etc., were kept as nearly price did not seem bright. The object of our vTork constant as possible. The results of t h e series were was, therefore, t o find a feasible and profitable process as follows: Back Pressure of System-Lbs., . , . . . . . . . . . , , 0 20 30 45 60 90 for t h e production of a satisfactory supply of gaso- Ilield of Saphtha-Per cent. , , . . . , , . . . , , . 2 7 9 13 18 23 line from some hea.i-y fuel oil or similar cheap hydroThese experiments were repeated after filling t h e carbon oil. of tile and brick. At 40-in, t u b e with broken pieces In all of the samples of gasoline which we had examined, made by so-called “cracking ” processes, a 90 Ibs. pressure we obtained a yield of 2 6 . z per cent, considerable amount of unsaturated hydrocarbons, which was repeated twice. T h e naphtha obtained in these experiments was tarry matter, etc., was present. I t was, therefore, ,
1
ADDlication has been made by the author for patents on this process.
1
U. S. Pat. No. 1,049,667.
,
Feb., 1916
T H E J O U R N A L O F I N D U S T R I A L A N D ElVGINEERING C H E M I S T R Y
slightly straw-colored; it possessed a distinct odor a n d was attacked more or less vigorously b y cold, concentrated sulfuric acid, proving t h e presence of unsaturated hydrocarbons. T h u s far we h a d succeeded i n showing: I-That pressure is essential. 2-That a combination of pressure and superheat is desirable. 3-That a refractory material in the superheated portion is desirable. 4-That carbonization, to a certain extent, takes place in the retort. 5-That the naphtha did contain unsaturated hydrocarbons. This gave us sufficient d a t a t o s t a r t on t h e second main problem of our work, t h a t of hydrogenating t h e unsaturated products. Mention has already been made of our intention t o obtain nascent hydrogen b y means of t h e action of steam on iron chips. This, i t seemed, might easily be done i n t h e chamber in which t h e oil vapors were superheated a n d so much of t h e cracking took place. T h e iron chips would have t h e advantage of acting as a refractory material t o
11j
ture measured at Dz were mixed with t h e superheated steam i n t h e Tee H , t h e mixture t h e n passing on through t h e cracking a n d hydrogenating chamber K a n d out a t a temperature indicated a t D3, into t h e condenser L; t h e temperature of t h e condensate was indicated a t Dd a n d back pressure, indicated at G4, on t h e apparatus, was regulated b y valve M . The condensate was collected in N where t h e corfdensed excess steam separated from t h e oily condensate, a n d was drawn off at t h e bottom, while t h e gases after bubbling through t h e condensate, escaped a t t h e t o p through t h e t r a p 0 a n d meter P a t a pressure of I O in. of water, maintained b y bubbling through t h a t depth of water. T h e details of t h e process were as follows: Steam was obtained from t h e Power P l a n t , about one-quarter mile away; its quality probably was not much above 90 per cent dry steam. A T y p e T-B-z General Electric Co. steam flow meter was used. Fig. 11 shows a cross section of t h e superheater C, which consisted of jj t o 60 f t . of ’/a2 in. wall b y 11/4
W FIG.I-PLANOF APPARATUS A-Valve GI Gz Ga Ga-Pressure Gauge H--2 in. X 2 in. X 1 in. Hydraulic T B-Steam Flow Meter 1-2 in. Hydraulic L C-Superheater DI DZ Ds Da-Well for Pyrometer H t o 1-2 in. Hydraulic Tube J1 Jz Js-Hydraulic Malleable Flan e Unions E-Retort JZt o Ja-2 in. I. D. Seamless Steel %be F-Check Valve
retard t h e flow of t h e oil vapors a n d t h e nascent hydrogen would be present t o act upon t h e unsaturat e d products a t t h e moment of their formation. I n connection with t h e action of steam on iron i t is well t o bear i n mind t h e analogous reaction in t h e manufacture of water gas,l &.: C zHzO = COz 4 H a t about 600‘ C . , while t h e reaction becomes C H20 = C O Z H at about 1000’ C., from which we may venture t h a t best results are probably obtained at temperatures which are not too high. For t h e succeeding work, we built t h e experimental plant shown diagrammatically in Fig. I. Steam a t t h e pressure indicated b y GI was admitted through t h e valve A a t a r a t e indicated b y steam flow meter B a n d passed through t h e superheater C into t h e Tee H at a temperature measured a t D 1 a n d pressure indicated by GP. Oil was distilled from t h e retort E a t a pressure indicated b y G3. The vapors a t a tempera1
+
+
+
+
Thorpe’s Dict. App. C h e m , 1‘01. 11. p. 706.
IC-Cracking Chamber L-Condenser M-Valve for Regulating Back Pressure N-Apparatus for Collecting Condensate and Separating Condensed Steam 0-Trap for Separating Liquid from Gases Formed P-Meter for Measuring Gases Formed
in. 0. D. “Shelby” cold-drawn seamless steel mechanical tubing bent into a trough-shaped coil of j1/2 turns, t h e t o p coil of which was about 2 0 in. X 60 in., all joints being electrically welded. T h e tubing steel, containing from 0 . 1 7 t o 0 . 2 0 per cent carbon, seemed t o withstand excellently t h e severe conditions imposed; a scale of oxide appeared t o form both outside a n d inside t h e t u b e , which, if undisturbed, prevented further rapid corrosion. Crane’s malleable iron pipe fittings for I.joo lbs. pressure were used throughout. Temperatures were measured b y Hoskins’ base metal thermocouples connected t o one meter b y means of one of their four-point selective switches. The retort was made b y drilling a Io-in. hole in a piece of 12-in. shafting a n d welding on a collar for bolting a n d sealing t h e top. T h e cracking chamber consisted of one piece of “Shelby” seamless steel mechanical tubing in. 0. D., 1/16-in. wall b y 7 ft. long enclosed in a furnace with 4-in. wall built of fire brick, a n d heated b y natural gas; this tube was filled with iron a n d steel shavings. The gas burners used for superheater a n d Cracker” are shown i n detail in Figs. III a n d I V : t h i s
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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
construction gave equal distribution of the flame throughout t h e entire length of t h e burner. I n conducting t h e experimental work, t h e following factors were t o be studied: I -Confirmation of our previous opinions as t o the desirability of pressure. a-Rate of flow of steam as compared to the amount of oil. 3-Temperature of the steam entering the Tee H. 4-Final temperature of the mixed vapors a t D8. 5-The rate of distillation of the oil, 6-The construction of the cracking chamber. 7-The nature of the catalyzer used. The first series of experiments made with this apparatus was t o study t h e influence of pressure. The type of burner shown .in Fig. 111, having a n drdinary air mixer, was used, b u t with it we could not get anything like the desired temperatures (we had no pyrometer at this time); the pressure a t G:! and GI was maintained at a point which gave a n average flow of steam of about I O O lbs. per hour; all other factors were kept a s nearly constant as possible. The results were as follows : Back Pressure a t Ga-Lbs. per sq. i n . , . , , . . . . , . , 60 75 90 100 Yield of Naphtha-Per cent. , , . . . . . . , . . . . . , . . 9 . 0 10.0 11 . O 1 1 . 5 ,
Although these results are loa. as compared with our previous experiments without steam, t h e same
Vol. 8, No.
ments such a n instrument was installed. sults obtained are given in Table I .
2
The re-
TABLE I
at
DI
Without pyrometer 20 min. 30 min. 15 min. 18 min. 25 min. 15 min.
585’ C. 560 605 480 490 525
a t Ds densate Bright red ... Dull red
cent 15 12 . . . 14 13 , . . 41° BC. 15 38 18 38 12 37 12 38 12 4 36 . . I
645O C. 635 635 635 640 600
cent 34.0 29.5 34.0 34.5 34.2 30.5 25.0 22.0 22.0 18.0
ft.
..
21 20 21 30 26.1 15.0 17.5 12.2
These results indicate t h a t t h e steam’ should be heated t o about 600’ C. before mixing with the oil vapors, which must in t u r n be distilled so as to pass through the cracking chamber a t the proper rate, which would in all probability depend upon the length of t h e cracking period ST;e next wished t o determine the effect of increasing t h e length of t h e cracking chambtr upcln the rate a t which t h e oil could be fed into the apparatus, therpby obtaining d a t a which would ennbie u s t o design a commercial plant; more J w r vi‘ t 11 the flar,es hitting t h e tube only once, thcn y o m g U T ) th3 ch,mii?y, we were losing n vast am-iunt of heat n hich was being measured in terms of g:is supplied t o the furnace i s 3“Trr
FIG,II-STEAXSUPERHEATER
tendency t o increase with pressure is evident, t h e low yields being caused b y low temperatures. We think, therefore, t h a t it has been conclusively demonstrated t h a t pressure is essential. It would have been inferesting t o have studied t h e effect of pressures higher t h a n I O O lbs., but for our work we were limited t o 1 0 5 lbs. pressure on t h e steam line; we did not think it worth while t o make provisions for higher pressures inasmuch as difficulties would be encountered in the safe operation of a commercial plant under greater pressure a t t h e high temperatures in use. After t h e just mentioned series of experiments, t h e burners were all fitted with compressed air mixers as shown in Fig. VI ; these burners gave excellent results. We now performed a few experiments t o determine the best rate of flow for t h e steam. T h e best results, judging from t h e appearance of the product, ‘sere obtainecl with pressure at G:! about Ioo-Ioj lbs. and the pressure a t G4 about go lbs., which gave us about I O lbs. of steam per gallon of oil. I n all subsequent m7ork, the steam was regulated accordingly. Our work had been carried on without a pyrometer up t o this point, b u t during this series of experi-
FIGSI11 AN? IV-SPECIAL GASBURNERS
fuel. The “cracking” chamber was therefore changed t o t h e construction Gliown :n Figs. T‘ and V I : aa/,-in. 0. D. by l/lfi-in wall 3-11 per cent nickel steel seamless mechanical tubing was used; unions were provided after each passage thrcugh the furnace in order t o permit t h e introduction of t h e refractory catalyzer and t h e frequent renewal of the same. T h e series of experiments recorded in Table I1 was intended as a check upon t h e indications of Table I under t h e just mentioned changed conditions. b u t does not present a clearly defined series of experiments w-th only one factor varied a t a time, and for various rea sons was not carried t o a conclusion. Chips and shavings of iron and steel were used as a catalyzer in t h e tubes of t h e cracking chamber. For the best results they should be renewed rather fre quently, since a scale of oxide forms on the outside which renders t h e m less active. We performed a few experiments with about 5 lbs. of nickel chips and nickel wire gauze mixed with t h e iron shavings. After about a week, most of the nickel had disappeared nor could we see a n y marked improvement in the product while using t h e nickel.
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
Feb., 1916
T h a t we were able t o produce hydrogen was shown b y running s t e a m alone (no oil) through t h e apparatus, thereby obtaining a gas a t t h e r a t e of about 5 feet per hour, which analysis showed t o be nearly pure hydrogen. Several experiments were made, using, in place of t h e new oil, residues from which t h e n a p h t h a formed i n previous runs h a d been distilled with similar conditions; t h e net yield was about t h e same. We also tried placing t h e condensate recovered in N back in t h e retort before distilling off t h e n a p h t h a , a n d found t h a t gas was not formed faster t h a n could be attrib-
117
small amounts as z gallons in so large a n apparatus, i t would be easy t o lose quite a considerable percentage. We see no reason why t h e loss could not be kept under I O per cent in operating a plant on a commercial scale. T h e n a p h t h a obtained b y our process differs very little i n appearance from commercial n a p h t h a ; i t is very nearly water-white a n d has very little unnatural odor; it is decidedly superior t o t h e samples of commercial “cracked” n a p h t h a which we have examined. Upon treating our product with sulfuric acid, i t was acted upon less t h a n a n y commercial “cracked” n a p h t h a
TABLE I1 Rate of EXP. distillation No. Per sal. of oil 1.. < . . . . 17 min. 2. 25 min. 3 12 4 ...................... 10 5 10 6 ..................... 7 7 7 15 8.. 9 10 10 7 11 ..................... 7
.............. .................... ..................... ..................... ..................... ...................
..................... .....................
Av. TEMP.(“C.) Steam Mixture 625 645 No superheat 400 560 590 540 550 580 605 575
uted t o t h e action of t h e steam on t h e iron until t h e temperature a t D2 of t h e oil vapors was over 300’ C., showing t h a t t h e lighter portions were broken down further only with great difficulty. A few experiments were made upon a very viscous a n d dirty Ohio crude oil, having a specific gravity 36’ B.; i t yielded 2 7 per cent b y fractionation a n d collecting t h a t portion which came over below 175’ C., it contained about z per cent moisture. We r a n this oil through t h e process without previously distilling off t h e n a p h t h a which it contained. Assuming t h a t
k 8
FIG.V
k
FIG.V I VI-CRACKING CHAMBER A-Compressed Air Inlet H-Fire Brick B-Gas Inlet I-Red Brick Ja Ja J4 J p H y d r a u l i c Malleable Flange Union C-Flue K-I X 11/4 in. Iron Bar Support Ds-Well for Pyrometer L--2 in. I. D. Seamless Steel Tube E-Partition F1 F n Fa-Baffle Plate M-Steel Shavings G-Burner FIGS.V
AND
none of this n a p h t h a was broken u p into gas a n d t h a t t h e remaining 73 per cent produced 34 per cent of n a p h t h a in t h e process, we would expect a total yield of j 1 . 8 per cent; as a matter of fact, t h e total yield of n a p h t h a obtained was 5 4 . 5 per cent. T h e loss due t o t h e formation of gas was high. T h e residues, after t h e n a p h t h a h a d been distilled, was as good, for future use, as t h e fresh L’Distillates” (Paragraph 4). The greatest item of expense in t h e process seems t o be in t h e amount of oil lost through carbonization, gas formation, etc. When we obtained t h e best net results, this loss, in our experimental plant, averaged from I O t o 1 2 per cent. When starting with such
Sp. gr. of condensate 34.0’ Be. 38.0 35.5 36.0 35.5 39.0 34.0 37.0 36.0 34.5 36.0
YIELD OF GAS OF Loss NAPHTHA FORMED APPEARANCE Per cent Per cent Cu. f t . CONDENSATE A little carbon 38.0 63.2 20 Very Very much clear free carbon 115.4 50 38.5 5 20.0 18.0 10 36.4 Very clear 26.0 25.0 Very clear 8 25.5 74.0 Very much free carbon 35 33.0 55.0 Some carbon 18 26.5 23.6 Very clear 15 26.0 39.3 Some carbon 20 30.0 59.2 Fair 10 24.0 Fair 15 30.0 56.2
which we have seen, in spite of t h e fact t h a t it h a d not been subjected t o a n y of t h e usual washing treatments, our purification having been limited entirely t o distillation. Several gallons were tried in motorcycle a n d automobile motors; in these tests there was no apparent difference between our n a p h t h a a n d commercial 7 2 ’ n a p h t h a ; we looked especially for such troubles a s carbonization, but could find no evidence of them. COST OF NAPHTHA P R O D U C E D
The cost of n a p h t h a produced b y this process may be estimated as follows: Our experiments show t h a t t h e entire apparatus could be maintained a t t h e proper temperature, a n d t h e oil distilled, b y t h e use of 30 cu. f t . of natural gas as fuel, per gallon of raw oil; natural gas if computed a t i t s equivalent in coal is not worth more t h a n 7 cents per 1000 cu. ft. It must be remembered t h a t our furnaces were designed with t h e view t o easy manipulation rather t h a n economy of fuel; in a commercial plant, t h e whole thing could be enclosed in one furnace a n d waste heat from t h e superheater used t o heat t h e cracking chamber a n d t o vaporize t h e oil. T h e product could be separated b y fractional condensation in a dephlegmator witho u t t h e use of additional heat. T h i r t y pounds of steam, a n d very probably much less, would be amply sufficient. Steam m a y be produced for 6 cents per 1,000 lbs. One gallon of n a p h t h a could be produced from 3 l / ~ gallons of raw oil, leaving t h e residue, minus about I O per cent loss, worth a s much as before. The cost would therefore be: One gallon raw oil (converted). . . . . . . . . . . . . . . 10 per cent of 31/3 gals. oil lost a t x c per gal.. . 100 feet of gas a t 7c per 1000.. . . . . . . . . . . . . . . 30 lbs. of steam a t 6c per 1000.. . . . . . . . . . . . . .
= x cents = r / 3 cents = 0.007 cent = 0,002 cent
Which may be expressed in t h e form of t h e equation = 1.33.x .O.g where C = cost of n a p h t h a obtained i n cents per gal. X = cost of raw oil in cents per gallon.
c
+
I
18
T H E J O C R N A L O F I N D C S T R I A L A N D ENGINEERILVG C H E M I S T R Y SC‘ 31 M A R Y
These experiments have established t h e following facts: I-That a satisfactory n a p h t h a may be obtained b y means of this process wherein t h e oil is cracked in t h e presence of nascent hydrogen. 2-That superheating t h e oil vapors is desirable for “cracking.” 3-That pressure is necessary for “cracking.” a combination of pressure a n d superheat 4-That is essential. 5-That t h e presence of a refractory material i n t h e “cracking chamber” acts as a catalyzer, aids t h e “cracking,” a n d increases t h e yield of n a p h t h a obtained. 6-That hydrogen is formed in t h e manner described, a n d t h a t i t evidently does unite with a greater portion of t h e unsaturated decomposition products formed, producing saturated compounds. 7-That iron or steel shavings i n t h e cracking chamber constitute a satisfactory catalyzer. 8-That t h e catalyzer should be frequently renewed. 9-That t h e yields of n a p h t h a obtained increase a s t h e pressure is increased u p t o IOO lbs.; above t h a t pressure we have no d a t a . Io-The best results were obtained when using about I O lbs. of steam per gallon of oil. 11-That t h e steam should be superheated t o a t least 600’ C. before mixing with t h e oil vapors. 12-That t h e mixture of superheated steam a n d oil vapors should be heated t o 650’ t o 675Oin t h e “cracking chamber.” 13-That t h e residue, obtained b y distilling off t h e n a p h t h a formed, is worth just as much as t h e original “ r a w ” oil. 14-That carbonization takes place in t h e retort a n d more or less gas is formed in t h e process. I 5-0ils having higher boiling points are “cracked” easier t h a n those having lower boiling points, b u t t h e q u a n t i t y of gas formed is greater. 16-That t h e cost of n a p h t h a produced b y this process may be approximately expressed b y t h e equation c = 1.33% 0.9, where C = t h e cost of t h e n a p h t h a in cents per gallon, X = t h e cost of the starting oil in cents per gallon. As t o future work on t h e problem, we have considered t h e following: I-Nore careful s t u d y of t h e temperature t o which t h e steam should be superheated before mixing with t h e oil. This might lead, in t h e construction of a commercial plant, t o placing t h e steam superheater next t o t h e fire a n d utilizing t h e heat for cracking, after it leaves this superheater. 11--A s t u d y of spraying t h e cold oil into t h e superheated steam in a mixing a n d l-aporizing chamber, which later might or might not have t o be heated. 111-X more careful study of t h e construction of t h e cracking- chamber, a n d t h e method of passing t h e vapors through t h e same, with t h e idea of determining whether it is not better to heat the vapors t o t h e desired temperature as quickly as possible.
+
Vol. 8 , NO.
2
In conclusion, t h e writer desires t o express his t h a n k s t o Mr. W. W. Sanders a n d t o hlr. L. M . Bourne, under whose supervision these experiments were performed, for their interest a n d suggestions. CHEMICAL LABORATORY OF THE GOODYEAR TIRESr RUBBERCOXPANY 4KR021, OHIO
REFINING VEGETABLE OILS’ By CHARLESBASKERVILLE
Crude vegetable a n d animal oils contain a variety of impurities traceable t o a great variety of causes. The character of t h e crude oil depends not only upon t h e kind a n d part of t h e vegetable (wood, n u t , seed, etc.) or animal (fish, whale, etc.) used, b u t t h e quality of t h e raw material a t t h e time of expressage or extraction (rusting, rotting, fermentation, sprouting, heating, etc.), t h e method followed, t h e care exercised in t h e process, a n d t h e conditions t o which t h e oil is subjected prior t o its refining. I t is not proposed t o discuss these matters in detail, as this communication deals more specifically with certain of t h e vegetable oils. ,4 distinguished oil chemist in a recent interesting summary of t h e “Contributions of t h e Chemist t o t h e Cottonseed Oil Industry,”* has said, “ t h e chemist * * * found t h a t t h e quality of t h e oil closely followed t h e free f a t t y acid p r e ~ e n t ” a~n d “ T h e chemist’s greatest service t o t h e industry has been in t h e refining of t h e oil, * * * * and finally bringing into use t h e tintometer for measuring t h e color against standard glasses * * * * .’14 T h e present customary practice for refining vegetable oils referred to depends upon neutralizing t h e free f a t t y acids in t h e crude oil, usually b y agitating t h e oil with a n aqueous solution of a n alkali, t h e strength a n d t h e amount having been previously determined b y laboratory tests, agreed upon as a standard, a n d t h e n heating t h e mixture during agitation t o a suitable temperature until t h e oil “breaks.” The mass is t h e n allowed t o stand until t h e “foots” settle t o t h e bottom of t h e kettle, when t h e supern a t a n t oil is drawn off b y means of a swivel siphon. Invariably some “ d r e g ” floats on t o p of t h e oil. If this be very great, its settling is sometimes facilitated b y throwing salt on t o p of t h e oil in t h e kettle. I n a n y event, t h e oil drawn off is clouded, perhaps on account of t h e presence of some dissolved soap, globulated moisture and suspended matter, doubtless colloidal in nature. This oil is t h e n “brightened” a f t e r drawing off, b y throwing in small amounts of fuller’s earth, heating again, a n d passing through a filter press. The time-factor in settling (6 t o 1 2 hours) of t h e “foots” materially affects t h e completeness of t h e separation referred t o above, but in any event the “foots” is wet with oil. The “ f o o t s ” also entrains oil. Consequently, during t h e rush season, t h e effi1 Read before the h-ew York Section, American Chemical Society, April 9. 1915, and the Inter-State Cottonseed Crushers’ Association, Birmingham, Ala., M a y 18, 1915. Since brought up-to-date, Jan., 1916. 2Wesso11, THISJOURNAL, 7 (1915), 2 7 7 . 3 I have determined that this is true only in a general way, as was no doubt meant by the nriter quoted 4 One familiar with the color changes in glass may question the real accuracy attainable in the use of such standards. However, it is the best now available.
