April, 1924
I T D L - A T R I A L A N D ENGIATEERING C H E M I S T R Y
341
Coconut Oil Refining' Factory-Scale Investigation of Refining of Coconut Oil and Manufacture of Coconut Butter (Coconut Oil Stearine) By Alan Porter Lee2 INDIAREPININGCO.,PHILADELPHIA, PA..
T
*
HIS report is the reREFINIKGMETHODSAND This paper reports the results obtained in a short period of opcrasult of the operation CLASSIFICATION OF LOSSES tion of a coconut oil refinery, started and cbmpleted with the plant of a coconut oil reentirely empty of materials. The oarious steps in the operation The most recent work finery over a short period, are described, their eficiency discussed, and the yields and losses depublished on losses in refinstarting and finishing with termined, recorded, and classified. ing edible oils is that of the plant entirely empty of 439422.6 g g . of crude coconut oil with an aoerage free fatty acid Thurman13who has shown oil. This condition was becontent of 2.579 per cent (calculated as lauric) were neutrplized, that coconut oil contains lieved to furnish an excelwashed, dried, bleached, pressed in hydraulic presses for separation smaller amounts of proteinlent opportunity for a pracof hard butter, and the hard butter deodorized. The operations were like substances and phostical investigation on a carefully checked by weighings, measurements, and analyses in order phatides than are found in commercial scale of the to determine the percentage of acid oil produced and the percentage the other well-known vegeefficiency of the various of shrinkage at each step in the operation. These results are said to table oils investigated by operations, and of the varicompare faoorably with usual practice in vegetable oil refining, but him, including cottonseed, ous losses (avoidable and to be subject to further improoemenf at seoeral stageeof the process. corn, peanut, and soy bean u n a v o i d a b l e ) attendant The net results were as follows: oils. upon the work. From a Kg. Per cent The refiner must remove commercial standpoint it 35.775 157,200.5 Hard butter 67.325 251,886.8 all the necessary losses, and Light oil was, of course, desirable to 5.519 24263 6 Acid oil his aim is to make such re1.381 obtain the best and most 6:071: 7 Shrinkage moval as complete as possieconomical results, and par100.000 439,422.6 ble, a t the same time reticular care was exercised to ducing attendant losses of preserve comdete records bf the several operations in order to determine the extent, and oil to a minimum. The ideal of operation for which he the true position in the process, of the shrinkages that are strives is to remove all the impurities without any other losses, but the ideal has never been attained in vegetable oil inevitable concomitants of all vegetable oil refining. The purpose of refining vegetable oil is to produce edible refining and the undesirable losses of oil involved in refining products, which must, as far as possible, be free from all are considerable. These losses are of two classes: first, losses of neutral oil forms of impurity, The crude oil, as received by the refiner from the mills, contains a variety of impurities, which are into free fatty acids, which are a by-product of less value than removed from the oil-bearing seeds or nuts and retained in the the main edible products; and second, actual disappearance of oil from the refinery through small leaks, spills, absorption oil. These impurities may be classified as follows: by bleaching materials, losses in water used for washing, as 1-Moisture and volatile, including small percentages of water glycerol lost by saponification of neutral oil in the refining and the odorous and flavoring substances which, althougfi present process, and sometimes (in all refineries) in ways apparently in very sinall amounts. give to each oil its characteristic odor and entirely unaccountable. flavor. It was for the purpose of classifying and evaluating these 2-Gasoline-insoluble impurities, which include traces of meal, hair from press cloths, bran from the hulls of seeds or nuts, sand, losses that careful records were kept of the test operations etc. described herein. 3-Free fatty acids, produced by the saponification, probably The first step in vegetable oil refining as practiced today enzymatic, of a portion of the oil, which may take place either is the removal of the third class of impurities mentioned before ox after its removal from the seed or nut. (The free e., the free fatty acids. This is accomplished in glycerol resulting from such saponification is apparently quickly above-i. . further decomposed and volatilized, as there is very little evidence practically all plants by treating the oil with a solution of of the identification of free glycerol in vegetable oils containing caustic soda in quantity sufficient to form sodium soaps of all considerable amounts of free fatty acids.) the free fatty acids. I n practice, however, it is found neces4-Coloring matter. sary to use an excess of caustic solution above the theoretical 5-Nonfatty materials (gasoline-soluble), probably waxes, amount, in order to grain out the soap and cause it to settle alcohols, and other unsaponifiable matter, present only in very out of the neutral oil, and to facilitate the precipitation of small amounts. the nonglyceride constituents, such as coloring matter, resins, The removal of all these impurities to the fullest possible etc. Unfortunately, this excess attacks some of the neutral extent is essential to making the oil edible. They will oil, saponifying it and forming additional soap, which in therefore be classified a s necessary losses, although some of settling carries down mechanically a further amount of neuthem, particularly the free fatty acids, are converted into tral oil, which cannot be fully recovered by known methods. The soap also carries with it the bulk of the second class of salable by-products, and are therefore not recorded as net necessary losses-i. e., the gasoline-insoluble and a portion of losses of weight in the refining operations. the coloring matter. The soap does not settle perfectly, and I Prestnted under the subtitle before the Division of Agricultural and it is necessary to wash the oil with successive portions of hot Food Chemistry at the 66th Meeting of the American Chemical Society, water, which, when settled out and drawn off, takes with it Milwaukee, Wis., September 10 t o 14, 1923. 2
President of company.
THIS JOURNAL, 15, 395 (1923).
Q
342
INDUSTRIAL A N D ENGIA’NEERIXG CHEMISTRY
considerable soap and some neutral oil. This wash water is generally saved for further treatment, which will be referred to later. Thus, in the first two steps of refining-i. e., neutralizing and mashing-the following opportunities for losses are encountered: -4-Necessary losses, irrecoverable (1) A portion of the moisture (2) Most of the gasoline-insoluble B-Necessary losses, recoverable as by-products (1) Moisture (in sniall part) ( 2 ) Gasoline-insoluble (in small part) (3) Free fatty acids (practically all) (4) Coloring matter (in part) ( 5 ) Unsaponifiable matter (in part) C-Undesirable losses, of the first class (1) Neutral oil saponified ( 2 ) Neutral oil mechanically entrained by soap stock (3) Neutral oil mechanically entrained by wash waters D-Undesirable losses, of the second class (none)
After the oil has been washed as rree of soap as possible, it is dried, either in vacuo or under atmospheric pressure, and agitated with bleaching agents to remove as much as possible of the fourth class of impurity, the coloring matter. This removal is effected by mechanical absorption by the bleaching agents (fuller’s earth, etc.), which are then removed from the oil by filter-pressing. The bleaching agents, however, absorb and retain a percentage of the neutral oil, as well as coloring matter and dried soap; and as the spent bleach has no value, in the third and fourth steps of refining-i. e., drying and bleachingthere are opportunities for the following losses: A--Necessary losses, irrecoverable (1) Moisture (entire remainder) (2) Gasoline-insoluble (entire remainder) (3) Free fatty acids (entire remainder, as soap) (4) Coloring matter (in part) B-A’ecessary losses, recoverable as by-products (none) C-Undesirable losses, of the first class (none) D-Undesirable losses, of the second class (1) Neutral oil absorbed by bleaching materials (2) Saponified neutral oil absorbed by bleaching materials
In the refinery where the work herein described was conducted, a special department produced coconut butters of various melting points by a process requiring niuch handling of the material. In this department there is considerable waste due to spills, absorption of oil by floors, flowage to drains, etc. Moreover, some of the oil reclaimed from floors and equipment is of such poor quality that it cannot be made edible and must be sold with the free fatty acids as a byproduct. The fifth, or pressing, operation therefore offers opportunities for losses as follows: A-Kecessary losses, irrecoverable (none) E-Necessary losses, recoverable as by-products (none) C-Undeszrable losses, of the first class (4) Neutral oil scrap, from pressing, unfit for edible purposes and therefore added to free fatty acid by-product D-Undeszrable losses, of the second class (3) Neutral oil lost and wasted in pressing
The final operation in the manufacture of edible vegetable oils, sixth in order in the refinery herein referred to, is deodorization, or renioval of characteristic flavors and odors, the ideal edible oil being free from any taste or smell whatsoever. Deodorization is accomplished by distillation in vacuo in a current of superheated steam, the flavors and odors passing off in the steam, and the edible oil remaining in the still. From the still the oil is removed to a cooler, and after cooling and filtration for clarification it is ready for shipment. In the deodorizing operation a certain amount of neutral oil and some free fatty acids-of which a trace remains after neutralizing-and coioring matter are entrained with the
Vol. 16, No. 4
steam, appearing with the condensed volatile matter in the condensed water of the hot well. Part of this mixture of materials may be skimmed off the hot well and added to the free fatty acid by-product, but a portion is lost in the condensing water which flows to the sewer. The opportunities for loss in deodorizing are, therefore, as follows: A-Xecessary losses, irrecoverable ( 1 ) Volatile matter (in part) (3) Free f a t t y acids (in part) (4) Coloring matter (in part) E-Necessary losses, recoverable as by-products ’ (I) Volatile matter (in part) (3) Free fatty acids (in part) (4) Coloring matter (in part) C-Undesirable losses, of the first class (5) Neutral oil entrained by steam but recovered as by-product D-Undesirable losses, of the second class (4) Neutral oil entrained and lost in condensing water
The seventh operation of a vegetable oil refinery, such as the one under discussion, consists of the treatment of the byproduct, soap stock, which in this case was acidified and sold as coconut acid oil. The first step in the treatment consists of boiling for the recovery of as much neutral oil as possible, thereby reducing the undesirable losses ( 2 ) and (3) of the first class under the neutralizing and washing operations. The neutral oil so recovered is returned to the neutralizing and washing tanks, instead of being lost into the cheaper byproducts. After this treatinent the soap stock and wash waters are treated with sulfuric acid, forming sodium sulfate and free fatty acids. These free fatty acids are greater in quantity than the original free fatty acids in the crude oil, as they contain the free fatty acid produced by saponification of some neutral oil in the refining process. They are also mixed with what neutral oil has been finally held mechanically; and even after several washings with hot water they still contain a portion of the moisture, unsaponifiable, and gasoline-insoluble impurities of the original crude oil. This mixture is sold in this condition as coconut fatty acids or coconut acid oil on the basis of 98 per cent saponifiable matter. Note.-The moisture and gasoline-insoluble impurities shipped in the by-product acid oil are not necessarily part of the actual materials which constitute the same impurities in the crude oil received but since they are sold as part of the by-product (up to 2 per’cent) it is proper to consider them as recoverable losses to that extent.
The glycerol set free by caustic saponification of neutral oil in the neutralizing process is washed out in the soap stock treatment and becomes an undesirable loss of the second class (irrecoverable) a t this stage of the process. Any neutral oil or free acid that might be mashed out in washing the coconut acid oil also falls under this heading of irrecoverable undesirable loss, as does the small amount of coloring matter washed out. Thus in the soap stock treatment department the following opportunities for losses are encountered: A-A‘ecessary losses, irrecoverable (none) B--Necessary losses, recoverable as by-products (none) C-Undesirable losses, of the first class (none) D-Undesirable losses, of the second class (5) h-eutral oil washed out of acid oil (6) Free fatty acid washed out of acid oil (7) Glycerol washed out of acid oil (8) Coloring matter washed out of acid oil
The sodium sulfate formed in treating the soap stock is washed out to the sewer in the washing of the coconut acid oil and is lost. Note.-It is of interest that during the recent World War the wash waters from the soap stock treatment were worked up for recowry of glycerol a i d sodium sulfate.
I S D USTRIAL A-VD ENGINEERIXG CHEMISTRY
April, 1924
OPERATIONS AND RESULTS The operat’ions hereunder described consisted of neutralizing, bleaching, and pressing thirteen tank cars and 6727.2 kg. of coconut oil and deodorizing the hard butter obtained in the pressing operation. The manufacturing plant was entirely empty of oil a t the beginning and end of the operation. The thirteen tank cars were received between April 15 and June 15, 1923, and the 6727.2 kg. were already a t the factory. Total net weight received in 13 tank c a r s . . , . . , . , , , , , , , . . 432,695.4 kg. On hand r i t p l a n t . . . . . . . . . . . . . . ... 6 , 7 2 7 . 2 kg. 439,422.6 kg. Total crude oil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,
AVERAGEANALYSIS01 13 TAXKCARSA N D 6727.2 KG. Free fatty acids: Oleic.. 3 . 8 7 per cent Lauric. . . . . . 2 . 5 7 9 per cent Color (Loyih 3 5 . 1 yellow, 5.85 red Setting point. . . . . . . . . . . . . . . . . 22.88’ C. Melting point. . . . . . . . . . . . . . . . 25..11° C. Moisture and i asoline-insoluble). 0 , 4 8 7 per cent COMPUTATION OF TOTALSHRISKAGE IN HANDLING 439,422.6 kg. Total oil received Hard butter shipped 157,200.5 kg. Light oil shipped 251,886.8 Acid oil ShiDDed 24,263.6
...............................
..
433,350.9 Shrinkage ...............................
6,071 7 kg. 1.381 per cent
343
In the neutralizing and bleaching departments the foregoing materials were used to produce a total of 413,240.4 kg. bleached oil. The labor utilized in neutralizing and bleaching totaled 1044 man-hours, indicating a production of 395.82 kg. of bleached oil per man-hour. No record was kept of steam and electricity consumption, the total of these having been distributed to the various departments on a previously established ratio, for cost, purposes. TABLE I-NEUTRALIZING AND BLEACIXING BALANCE SHEET. METHODA ---Kilokrams-Crude oil received Moisture and impjmities 2,137.7 Neutral oil mechanically held by acid oil 6,182.7 Oil saponified 5744.1 Free f a t t y acids 11:332.7 Bleaching absorption 785.0
439,422.6 kg.
Total Kg.
Caustic soda Fine salt Fuller’s earth Activated carbon Infusorial earth Water for washing oil
3106 1796.3 1552.3 821.8 169.0 114,875 liters
Kg per 100 Kg. Oil Produced 0.75 0 43 0.375 0.198 0 04 27 7 liters
cent-
0.487
100.00
1.405 1.307 2.579 0.179
26,182.2
5.957 94.043
--
413,240.4
Bleached oil produced
TABLE 11-NFUTRALIZING AND BLEACHING BALANCE SHEET.METHODB ---Per
-Kilograms-
439,422.6
Ciude oil neutralized Acid oil from neutralizing Moisture and impurities lost Glycerol lost Bleaching absorption
1,647.7 804.1 785.0
22,945.4
Bleached oil produced
cent100.000
5.222
0.373 0.183 0.179
-
Total shrinkage
NEUTRALIZIKG, WASHING, DRYIIUG, AND BLEAcHING--The oil was neutralized with a mixed solution of caustic soda and common salt, 0.15 per cent NaOH excess over the amount necessary to combine with the free fatty acids in the oil being uiied. There were thirty-nine separate neutralizings, giving an average batch of about 11,250 kg. After neutralizing, the oil was washed with from three to five portions of hot water, each wash totaling about 8 per cent of the weight of oil in the batch. All wtish waters were collected and treated for recovery of oil and soap. Soap stock was treated with salt and boiled to obtain maximum separation and recovery of mechanically included neutral oil. Reco1)ered oil was obtained from three sources, as follows: (1) trealment of soap stock and wash waters; ( 2 ) steaming filter presses; (3) steaming press bags in press room and general recovery from presses, trucks, etc., in press room. The total oil thus recovered and reneutralized equaled 23,841.8 kg., or 5.43 per cent of the total crude handled. Methods?are now in development for the entire elimination of this rehandling, with the possible exception of oil from steaming filter. presses. The washed neutral oil was dried in a vacuum drier and then bleached in vacuo. The maximum drying temperature was 82.2’ C., and the highest vacuum obtained 698.5 mm. of mercury. The bleaching absorbents were fuller’s earth and activated vegetable carbons. Before adding bleaching materials a very small percentage (0.04 per cent) of infusorial earth was added to absorb any remaining traces of dry soap which might reduce the efficiency of the bleaching materials. After agitation with bleaching materials in the drier, the oil was pumped into holding tanks, with agitators, and filtered through recessed-plate open-delivery presses. From the filter presses the oil flowed by gravity to the bleached-oil storage tanks, from which it was fed by gravity t o the graining tanks for the first step in the separation of the higher melting fraction or so-called “coconut stearine.”
r-Per
I
3,236.8
0.735
41 3,240.4
94.043
TABLE: 111-ANALYSIS OF NEUTRALIZING E F P I C I E N C Y Per cent Total acid oil produced from neutralizing (free fatty acids in acid oil100.00 per cent as oleic, 70.92 per cent as lauric) Acid oil produced from free f a t t y acid in crude Acid oil produced from neutral oil saponided Acid oil produced from neutral oil mechnnically entrained Moisture a n d imDurities in acid oil Glycekol loss from neutral oil saponified 4,940 kg. 4,940 kg. = 804.1 kg. 80 per cent Neutral oil saponified Neutral oil mechanically entrained
P e r c e n t of Crude
Kg.
22.945,4
100.00
5,222
11,332.7
49.42
2.579
4,940.0
21.50
1.124
6,182.7 490.0
26.95
__-
1.405 0.114
2.13 -
22,945.4
100.00
5.222
-
Total neutral oil converted to acid oil Kg. Total crude oil 439,422.6 Neutral oil t o bleachers 414,025.4
0.183 1.307
5,744.1 6,182.7
1.405 2.712
11,926.8 Per cent 100.00 94.23
-
Neutralizing loss bv oil Acid oil prcduced from neutralizing (loss by soap stock)
25.397.2
5.77
22,945.4
5.222
Average neutralizing loss
24,171.3
Ratio neutralizinn loss bv oil to free f a t t y acid Ratio neutralizing loss by soap stock t o free f a t t y acid Ratio average neutralizing loss to free fatty acid
-_ nip;,.
Lauric
1.57
2.23
1.42
2.03
1.495
2.13
5.496
TABLEIV-NEUTRALIZING E~FICIENCY ELIMINATING FACTORS O F MOISTURE AND
IMPURITIES
Total crude oil Moisture and impurities
Kg. 439,422.6 2,137.7
Per cent 100.000 0.487
Net crude Neutral oil t o bleachers
437,284,9 414,025.4
99.513
Per cent of Crude Clear (DryBasis) and
100,oo 94.58
23,259,5
5.42
Net acid oil (neutralizing loss by soap stock)
22,455.4
5.12
Average neutralizing loss
22,857.45
5.27
Neutralizing loss by oil Acid oil produced 22,945.4 Moisture and impurities in acid oil 490.0
.*
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
344 TABLE IV
(Concluded)
Ratio neutralizing loss by oil t o free fatty acid Ratio neutralizing loss by soap stock to free fattv acid Ratio avefage neutralizing loss t o free f a t t y acid Average color dried oil Average free fatty acid dried oil
Oleic
Lauric
1.47
2.1
1.39 1.43
1.98 2.04 12 6 yellow, 1 . 8 red 0.08 per cent
TABLE V-ANALYSIS OF BLEACHING EFFICIENCY -Kilograms----Per centTotal oil bleached 414,025.4 100.000 Absorbed in bleaching materials 785.0 0.189 N e t bleached oil Bleaching materials used: English fuller’s earth Florida fuller’s earth Total fuller’s earth Activated carbon A Activated carbon: B
413,240.4
99.811
27.3 1,525.0
649.1 172.7
1,552.3
0.374
-
Total activated carbon Infusorial earth
821.8 169.1
0.198 0.040 -
0.612 Total bleaching materials 2,543.2 Oil and coloring matter absorbed by bleaching materials: 788 kg. = 30.8 per cent of bleaching materials used = 23.6 per rent of spent earth removed from filter presses = 0.189 per cent of total oil bleached Average color of oil before bleaching.. . . . . . . . 12 6 yellow 1.8 red Average color of oil after bleaching. ......... 4: 0 yellow: 0.5 red Average removal of color. . . . . . . . . . . . . . . . . . . 8 . 6 yellow, 1.3 red Number of press cleanings., ................. 24 Average weight of oil filtered per press.. . . . . . 17,250.9 kg. 105.9 kg. Average weight of bleach per press., . . . . . . . .
Vol. 16, No. 4
That the separation cannot be based on these figures, however, has been ably shown by Bomer and Baumanq6 who have proved the presence in coconut oil of several mixed glycerides, the one of chief interest here being caprylolauro-myristin (melting point 15” C.), the presence of which undoubtedly shifts some of the lauric acid and myristic acid glycerides into the soft butter column, thus reducing the yield of hard butter. Under proper graining and pressing conditions, the maximum yield of hard butter reported in practice has been between 45 and 50 per cent. In the operations herein described the whole oil was run into shallow tanks holding about 1500 kg. each, and allowed to stand a t a temperature of 12.5” to 15.5” C. for 40 to 60 hours. The mass of grained oil was then broken up with shovels and placed in canvas cloths which held about 2.3 kg. each. These cloths were folded and placed under hydraulic pressure in open-type presses, with steel plates separating the cloths. The pressure was applied slowly and maintained as long as any of the “oleine,” or light oil, flowed from the pores of the bags. When preFsure was released, the press was unloaded and the “stearine” removed from the bags by hand, being then melted and pumped to storage tanks, from which it was drawn into the deodorizing stills for final treatment to free it from unpleasant flavors and odors. The light oil flowing from the presses was in this case loaded into tank cars and shipped without further treatment. The press room handled a total of 413,240.4 kg. of bleached oil and produced 157,841.4 kg., or 38.20 per cent, of hard butter, and 251,886.8 kg., or 60.95 per cent, of light oil. The total hours of labor were 4477 man-hours and 1920.75 womanhours. For purposes of reduction to a single unit one womanhour is taken to be equivalent to 60 per cent of one man-hour. This gives a total of 5629.5 man-hours labor in press room and shows 73.41 kg. of original whole oil handled per manhour and 28.036 kg. of hard butter produced per man-hour.
The free fatty acid content of the acid oil by-product indicates that 1.307 per cent of neutral oil was saponified in neutralizing, whereas the excess of 0.15 per cent NaOH used, above the amount necessary to neutralize the free fatty acids in the original oil, has a coconut oil equivalent of only 0.877 per cent. Thurman, in the paper previously quoted,B has shown that hydrolysis, or splitting of glycerides, occurs in washing coconut oil and also in the dilution and acidulation of coconut oil soap stock, due to the presence of combined caustic soda. The figures given above confirm this conclusion Total number of pressing?,. . . . . . . . . . . . . . . . . 624 Average whole oil per pressing,, , , . , , , , . . , , 662.7 kg. and show a loss of 0.060 per cent of the original oil as glycerol 252.9 kg. Average hard s t o c k , , ..................... Average light oil.. ....................... 403.6 kg. set free by hydrolysis (a close check of Thurman’s figure of 0.057 per cent). I n the figures given herein, this loss of TABLE VI-PRESS ROOMBALANCI? SHEET Per cent glycerol due to hydrolysis is included with that lost by diKZ. Per cent of Crude rect caust’icsoda saponification of neutral oil. Oil received from bleachers 413.240.4 100.00 94.043 -- PRESSING FOR HARDCOCONUT Bu~~~~-Lewkowitsch,~ 38.20 35.923 Hard stock produced 157,841.4 60.95 57.325 after Paulmeyer and Elsdon, gives.the composition of coconut Light oil produced 251 886 8 Scrap produced (to acid oil) 1:072:7 0.26 0.242 oil fat,ty acids as follows, approximately: Per cent
.............. ...................... ............... .............. ......................
-
...............
100.0
The problem of the manufacturer of coconut butters, or “chocolate fats,” is to separate the glycerides that melt above 28.9” C. from those of lower melting point and to obtain the highest possible yield of the former. Assuming all the fatty acids of coconut oil to be present as simple triglycerides, a theoretical grouping of the glycerides under hard and soft butters would be as follows: HARDBUTTER Caprin Laurin Myristin Palmitin Stearin
Per cent 10.0 40.0 20.0
6.5
Q.6 -
410,800.9 99.41 93.490 Shrinkage room 2.439.5 0.59 0.553 - in Dress AVERAGE ANALYSIS OF NEUTRAL WHOLE OIL Free fatty acid.. 0 . 0 8 per cent 4.01 yellow, 0.51 red Color.. Setting point.. 22.88O C. AVERAGEANALYSISOF HARDBUTTER 0.027 per cent Free fatty acid.. 4.0 yellow, 1.0 red Color.. Setting point.. 26.68’ C. AVERAGEANAGYSIS OF LIGHT OIL Free fatty acid.. . . . . . . . . . . . . . . 0.14 per cent Color.. ...................... 7 4 yellow, 1.6 red Setting point.. 20.3’ C.
SOFTBUTTER Per cent 2 Caproin 9 Caprylin 12 Olein
23
77.0
4 “Chemical Technology and Analysis of Oils, Fats, and Waxes,” Vol. 11.
...............
DEoDoRIzIn--In the operations herein described only the hard butter was deodorized. This step in the work consisted of distillation i n vacuo in a current of superheated steam, the oil remaining undistilled and the undesirable flavor and odor-causing substances passing over with the steam. The deodorizing vessel takes a charge of 1600 kg., and is equipped with barometric jet condenser and rotative dry-vacuum pump, the latter for the removal of noncondensable gases. I n the operation the vacuum averaged 686 mm. of mercury. The steam is. superheated in a separately fired heater burning anthracite coal. The deodorizing apparatus was operated a total of 540 5
Z.Nahr. Gennssm., 40, 97 (1920).
I S D U S T R I A L A N D ENGINEERIiYG CHEMIXTRY
April, 1924
345
hours and produced 157,200.5 kg. of deodorized hard butter, an aver:tge of 291.1 kg. per hour of operation.
Insufficiency of the data on some of the finer details of the operations makes it necessary to group two or three losses as a single amount and percentage in certain instances, and in TABLEVII-DEODORIZIXG BALANCESHEET others to report the loss as a trace. The very small actual Per cent Kg. Per cent Crude Oil percentage by weight of coloring matter and volatile matter Hard stock received from press room 157,841.4 100.000 35.923 ~ -justifies this conclusion in certain instances. Hard butter shipped 157,200.5 99.595 35.775 It should be of interest to all refiners of vegetable oils to deScrap produced (acid oil) 245.6 0.155 0.055 ~ -termine the actual -weights and percentages of coloring and 157,446.0 99.75 35.830 volatile matter removed from the oil, in order t o fill up the Shrinkage in deodorizing 395.4 0.25 0.093 present gaps in shrinkage accounting. COOLING, PANNIKG, AND PACKING-The deodorized hard TABLEXII-ACTUAL LOSSES OF Iv~ATERIAL butter was cooled by water circulation through a closed coil Per cent of Crude immersed in the butter, filtered through a clean press fitted Oil Kg. with cloth and paper, then molded in pans and solidified, Departments I and 2-Neutralizing and Washing before being wrapped in parchment paper, packed in poplar A-Necessary losses (irrecoverable) (1) Moisture and volatile 1,647.7 0.373 cases, and shipped. (2) Gasoline-insoluble 1 1,647.7 0.373 irrecoverable ACID O I L (BY-PRODUCT) PRODUCTION--After all possible Total B-Necessary l o s e s (recoverable as by-product) neutral oil was recovered from soap stock and wash waters, 0.114 (1) Gasoline-insoluble Moisture 460.0 (2) 1 they were treated with sulfuric acid to obtain a clear oil 2.579 Free fatty acids 11,332.7 Trace ..... 4) Coloring matter which eontains a high percentage of free fatty acids and is 5) Unsaponifiable Trace ..... known as coconut acid oil. C-Undesirable losses (converted into by-product) 1.307 (1) Neutral oil Saponified and hydrolyzed 5,744.0 There were 24,263.6 kg. of this by-product produced, (2) Neutral oil mechanically held by soap 1.405 (3) Neutral oil mechanically held by wash 6,182.7 which required 4611.7 kg. of 1.83 specific gravity sulfuric waters acid, or 19 kg. of acid per 100 kg. of acid oil produced. Total recoverable 23,749.4 5,405 0.183 804 1 The total labor in this department was 273.5 man-hours, Deduct glycerol lost 5.222 22,945.3 showing a production of 88.7 kg. of coconut acid oil per man- Net total recoverable Total losses 5.595 24,593 0 hour of labor.
i"'
-
TABLE
VIII-ACID
OIL BALANCE SHEET.
METHODA
'
Kg. 24,263.6
Total acid oil shipped
~ 22,945.4 1,072.7 245.5
Acid oil from neutralizing Acid oil from press room scrap Acid oil from deodorizer scrap
24,263.6
Percent 100.00 94.60 4.39 1.01
1OO:O
5.222 0.242 0.055
Departments 3 and +Drying and Bleaching A-Necessary losses (irrecoverable) (1) Moisture,and volatile Trace (2) Gasoline-insoluble Trace (3) Free t a t t y acid (as soap) Trace (4) Coloring matter D-Undesirable losses (irrecoverable) (1) Neutral oil absorbed in bleach 785.0 Trace (2, Saponified neutral oil absorbed in bleach 785.0 Total irrecoverable
5.519
Total losses
Per cent of Crude Oil 5.519
-
--
-
1
.....
..... .....
-
0.179
..... -
-
0.179 0.179
785.0
Department 5-Pressing TABLEIX-ACID OIL B A ~ A N C SHEET. E METHODB Kg. 24,263.6
Per cent of Crude Per cent Oil
100.00 - -5.519
Acid oil shipped
11,332.7 4,940.0
46.60 20.52
2.579 1.124
6182.7 1i072.7 245.5 490.0
25.46 4.39 1.01 2.02
1.405 0.242 0.055 0.114
24,263.6 ANALYSISACID OIL
100.00
5.519
Acid oil from free f a t t y acid in crude Acid oil from neutral oil saponified Acid oil from neutral oil entrained mechanically Acid oil from press room scrap Acid oil from deodorizer scrap Moisture and impurities in acid oil
- - -
Free fatty acids:
Impurities
.......... .......... (gasoline-insoluble) ....................
Per cent 100.00 70.92 0.14
TABLE X-SHRINKAGE ANALYSIS Ka. 1,647.7 804.1 785.0
Moisture and impurities lost Glycerol lost Bleaching absorption
-
- - -
Total neutralizing and bleaching shrinkage Press room loss Deodorizing shrinkage Total shrinkage
TABLEX I - L ~ ~ O I S C U R E
Per cent Per cent of Total of Crude Shrinkaae Oil 27.14 0.373 13.20 0.183 0.179 12.91
AND
3,236.8 2,439.5 395.5
53.25 40.24 6.51
0.735 0.553 0.093
6,071.8
100.00
1.381
- - -
IMPURITIES
Kg. Total moisture and impurities in crude oil 2,137.7 Moisture and impurities shipped in acid oil 490.0
ACCOUNT Percent 100.00 22.86
Per cent of Crude Oil 0.487 0.114
77.14
0.373
C-Undesirable losses (conversion into by-product) (4)Neutral oil scrap 1,072.7 Total recoverable 1,072.7 D-Undesirable losses (irrecoverable) (3) Neutral oil wasted in pressing 2,439.5 Total irrecoverable 2,439.j
-
1,647.7
SURVEY OF LOSSES The losses of material were discussed and classified earlier in this paper. I n Tables XII, XIII, and XIV the actual results of the operations are applied to these losses.
-
0.553
-
0.553
3,512.2
Total losses
0.795
Department 6-Deodorising A-Necessary losses (irrecoverable) 11) Volatfle 3) Free fatty acids 4) Coloring matter D-Undesirable losses (irrecoverable) (4) Neutral oil lost in condensing water Total irrecoverable B-Necessary losses (recoverable) (1) Volati!e (21 Free fatty acid 4) Coloring matter 5) Unsaponifiable C-Undesirable losses (recoverable) (5) Neutral oil entrained by steam, recovered as scrap Total recoverable
I
Total losses
Department 7-Soap
Trace Trace Trace
.
-
395.4 395.4
Trace Trace Trace Trace
-
D-Undesirable losses (irrecoverable) 5) Neutral oil washed out 6) Free fatty acid washed out 7) Glycerol washed out 8) Coloring washed out Total irrecoverable
/
..... ..... ..... .....
-
0.055
0.055
640.9
0.148
None None 804.1 Trace
-
804.1 -
..... ..... ..... -
0.183
0.183 0.183
OF LOSSES OF MATERIAL
(4) Coloring matter
Total B-Necessary losses (recoverable as by-product) (1) Moistune and volatile (2) Gasoline-insoluble (3) Free fatty acids
1
..... 0.093 0.093
245.5 245.5
804.1
Total losses
TABLE XIII-SUMMARY
.. .. .. .. ..
Stock Treating
- - -
Moisture and impurities lost as shrinkage
0.212 0.242
Kg.
Per cent
1,647.7 Trace Trace
0.373
1,647.7 490.0 11,332.7
..... ..... 0.373
0.114 2.579
346
INDUSTRIAL A N D EN 'GINEERING CHEMISTRY TABLE XIII-SUMMARYOB 1,ossEs OB MATERIAL (Concluded)
B-Necessary Losses (concluded) 4) Coloring matter 3) Unsaponifiable
l-
Total
=3.
Per cent
Trace Trace
..... -
Total necessary losses C-Undesirable losses (conversion of primary DrOdWt t o by-product) )il saDonified (less rrlvcerol~
Solution of Tin and Antimony Oxides'
.....
11,822.7 13,470.4
By Ernest0 Stelling
2.693
3.066
Vol. 16, KO. 4
Y A L E UNIVERSITY. N E W H A V E N ,
CONN.
W
HEN tin and antimony are converted into oxides by evaporation with nitric acid, they become insoluble, and in order t o dissolve them for further examination or for separation, it is common practice to use some method involving a fusion, which takes some time and offers difficulty Total 12,440.9 2.826 in getting the oxides entirely in a soluble form. D-Undesirable losses (irrecoverable) It has been found that when these oxides obtained as above (1) Neutral oil absorbed by bleaching materials 785.0 0.179 are digested with water containing some sulfur dioxide they (2) Saponified neutral oil absorbed by bleach Trace ..... 3) Neutral oil wasted in pressing 2,439.5 0.553 become readily soluble in hot hydrochloric acid. This observa4 Neutral oil lost in deodorizing 396.4 0.093 tion may have some interest in connection with the analysis eutral oil washed out of acid oil None ...., Free fatty acid washed out of acid oil None ..... of alloys containing these metals. 7) Glycerol washed out of acid oil 804.1 0.183 (8) Coloring washed out of acid oil Trace ..... The experiments were performed by using various amounts __ (0.2, 0.5, 1.0 gram) of powdered tin and antimony and mixtures 1,008 Total 4,424.0 of equal parts of both metals. Each sample was treated with Total undesirable losses 16,864.9 3.834 10 cc. of concentrated nitric acid and 10 cc. of water. Some of TABLEX ~ ~ - - ~ A B I l L A T I O NOf LOSSESCLASSIFIED AS (1) RECOVERABLEthese were evaporated to dryness on a steam bath, while others AS BY-I~RODUCT, A N D (2) IRRECOVERABLE were further heated to a dull redness. The oxides obtained K%. Per cent were treated with 50 cc. of a strong solution of sulfur dioxide RECOVERABLE AS BY-PRODUCT A-Necessarv losses and digested from 3 to 5 minutes a t about 60" C. Ten cubic 1) Moistire and volatile 490.0 0.114 f21 Gasoline-insoluble centimeters of concentrated hydrochloric acid were added and (3j Free fatty acids 11 332.7 2.579 $race the solution was boiled until no more sulfur dioxide was evolved. 4) Coloring matter Trace o) Unsaponifiable matter ..... The solution thus obtained was perfectly clear. The digestion B-Undesirable losses (1) Neutral oil saponified (less glycerol) 4,940.0 1.124 with sulfur dioxide changed the appearance of the oxides, caus(2) and (3) Neutral oil mechanically held soap stock and wash water 6,182.7 1.405 ing them to become more dense and settle more readily. 1,072.7 (4) Neutral oil scrap from pressing 0.242 On testing the solutions of tin and antimony chloride obtained 245.5 (5) Neutral oil scrap from deodorizer 0.055 it was found that both of the metals were in the higher valence, Total recoverable as by-product 24,263.6 5.519 so that reduction by the sulfur dioxides does not occur in either 2-IRRECOVERABLE A-Necessary losses case. This is further confirmed by the fact that the amount (1) Moisture and volatile 1,647 7 0.373 of sulfate present in traces as an impurity in the water con(2) Gasoline-insolu ble Trace 3) Free f a t t y acid ..... taining sulfur dioxide is not increased by the solution of the Trace 4) Coloring matter ..... B-Undesirable losses oxides. This was found by determining sulfate photometrically (1) Neutral oil absorbed by bleaching ma785.0 0.179 in the solution before and after the oxides were treated. On terials (2) Saponified neutral oil absorbed by bleachthe other hand, sulfur dioxide is taken up by the oxide, as shown Trace ing materials ..... 2,439.5 0.553 (3) Neutral oil lost in pressing by the following experiment: The residues obtained by treating 395.5 0.093 (4) Neutral oil lost in deodorizing None the oxides of tin and antimony with sulfur dioxide water were ( 5 ) Neutral oil washed out of acid oil Nohe ..... (6) Free f a t t y acid washed out of acid oil filtered and washed thoroughly. The residues were then treated 804.1 0.183 (7) Glycerol washed out of acid oil Trace ..... ( 8 ) Coloring washed out of acid oil with bromine and dilute hydrochloric acid. After the bromine 6,071.8 was removed the solution gave a strong test for sulfate. If the 1.381 Total irrecoverable oxides, after treatment with sulfur dioxide, are boiled until the 30,335.4 6.900 Total losses sulfur dioxide is removed from solution, they are no longer 409,087.2 93.100 Net refined oil obtained soluble in hydrochloric acid. As the compound was not crystalline, it was thought useless to analyze it. Chemical literature CONCLUSIONS already contains too many formulas of imaginary compounds. 1-The yield of hard butter was good, but considerably The following procedure is recommended for the treatment below theoretical possibilities. of an alloy containing tin or antimony or both: 4940
n
1 134
$
I
i-
I
a , . . .
-
2-The yield of acid oil was satisfactorily low in relation to the free fatty acid content of the crude oil. 3-The shrinkage was low for this class of operation, but might be reduced to a still lower figure by redesigning the pressing department in such a way as to reduce the losses of oil therein. 4-Other shrinkage losses besides that of glycerol have been reduced to absolute minimum, until such time as the refiner of coconut oil can obtain his raw material absolutely free from water, setMings, and other unsaponifiable impurities. &-Glycerol losses can be reduced in proportion to reduction in the percentage oi neutral oil saponified and hydrolyzed in the refining processes. 6-Refiners of edible oils may, with profit, investigate the sources of small losses of material in their manufacturing operations.
Treat 1 gram of the borings with 20 cc. of concentrated nitric acid and 10 cc. of water. Evaporate to dryness over a flame or a steam bath. Add 10 cc. of dilute nitric acid and warm. Filter and wash with dilute nitric acid. The filtrate will contain all the metals except the tin and antimony, which are retained as oxides on the filter paper. Up to this point this is a regular procedure for alloys. Wash the oxides into a beaker with 50 cc. of a strong solution of sulfur dioxide and digest from 3 t o 5 minutes a t 60" to 70" C. Heat to boiling, add about 10 cc. of concentrated hydrochloric acid, and boil until all sulfur dioxide is removed. If necessary to remove traces of the oxides from the filter paper, this can be treated in a similar manner. Tin and antimony will now be in solution as chlorides of the higher valence in the presence of traces of sulfate, which is a convenient form for further treatment. ACKNOWLEDGMENT
The writer wishes to express thanks to Professor H. W. Foote for his valuable suggestions and for his criticism of this paper. 1 Received
February 16, 1924.
