US1169155A - Process of refining oil. - Google Patents

Description

GEORGE M. HOLBROOK, OF CHICAGO, ILLINOIS, ASSIGNOR TO ARMOUR. AND COMPANY, I OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

To all whom it may concern:

No Drawing.

Be it known that I, GEORGE M. HoLBRooK, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes of Refining Oil, of which the following is a specification.

This invention relates to improvements and features of novelty in the processes of refining oil, and more particularly relates 'to the purifying of crude cottonseed oil for various industrial and food purposes, whereby to procure desirable qual1t1es of refined oil of higher grade as to color with less manipulation and with a smaller refin-- .ing loss than has been possible by other known methods.

It has heretofore been proposed, as for example, in United States Patent No.

1,007,642, granted October 31, 1911, ,to refine crude cotton-seed oil by first treating the oil with an aqueous solution of a water soluble alkalinesilicate, such for example, as sodium tetrasilicate, until the acidity of the oil is approximately overcome and then subjecting it to the action of an alkaline hydroxid, such for example, as sodium hydroxid, which brings about a precipitation of the soap-stock. Such a method as this has certain objectionable features, because sodium silicate seems to have a chemical effect upon the coloring matter in the crude oil which renders it more or less immune to further decolorization during the secondary treatment. Y i

The main object of the present invention is the provision of a method or process which will permit the purification of crude cotton-seed oil in such a way as to result in an oil of the desired color and with a minimum of refining loss. In order to do this, in view of the discovery of the detrimental action of the sodium silicate referred to, it is necessary to avoid the wellknown process specified above of treating the oil first with sodium silicate and then with sodium hydroxid.

In accordance with the principles of the present invention, the crude cotton-seed oil is treated initially with sodium hydroxid and then with a mixture of sodium hydroxid and sodium silicate, thisprocess having the advantage over the others'that the neutralizing of the free fatty acids out of Specification of Letters Patent.

namely 44 Baum,

Patented J an. 25, 1916.

Application filed November 15, 1915. Serial No. 61,503.

contact with the silicate prevents the setting of the color, which, if it occurred, would be difiicult or impossible to remove under furthertreatment. Under this process, a portion'of the color is removed during the first step and another portion during the second step, the sodium hydroxid constituting the vital or real refining agent, the silicate being used as a compacting or condensing agent for the foots or soapstock, to reduce the amount of neutral oil in such foots, or, stated difierently, to diminish the refining shrinkage.

The manner of performing this improved process, the percentages of ingredients employed, the temperatures reached, etc., depend upon the nature of the crude oil to be purified and the color to be attained in the refined product. We may assume, however, a typical case in which the crude cotton-seed oil has 1% of free fatty acids. To this oil is added 1%by weight of a suitable solution of caustic alkali, such as sodium particles of the oil with the caustic alkali to thoroughly neutralize the free fatty acids, which are always present in crude cotton-seed oil. Then a mixture of an aque-z ous solution of sodium hydroxid and an aqueous solution of sodium, silicate composed of 3% by .weight of the oil treated, 18 Baum, sodium hydr'oxid or its equiva: lent and of 1% by weight of the oil treated of sodium silicate of commercial grade,

perature of about 80 Fahrenheit, the temperature of the oil. and its contained solutions is slowly raised to about 115 Fahrenheit, whereupon the soap-stock will separate readilv and completely from the refined oil, which will be of much clearer and lighter color than in the crude state. In carrying out this process, the original caustic soda solution neutralizes all, or prac' tically all of the fatty acids, of the caustic preferably being used for this purpose of assuring complete neutralization, and it also precipitates a portion of the coloring matter and other impurities. The soap-stock is not.permitted to settle at this time, as it would ordinarily, until the silicate is introduced, which appara slight excess is added. After agitation for about 15 minutes at an initial tem- 45 a vegetable and animal oils, and is not limited ently, has the roperty ofcombining with the products 0 the previous refination and thereby the soap-stock thus formed settles in a compact, glassy condition, which more readily expresses the oil' and forms a soa -stock which separates from the oil easily y reason of. its increased specific gravity. lhe a itation is continued after the silicate is a ded until the, proper temperature is reached for the separation of the soap-stock in order to assure a complete intermixture of the ingredients. Stated somewhat differently, b carr ing out the process in the two steps, as in icated the final soap-stock or foots is precipitate in a compact, plastic, or glassy condition which tends to liberate 1part of the oil which might otherwise.

be he d in suspension mechanically.

As has been indicated above, the free fatty acids of'the oil are neutralized before the silicate is used, as the employment of such silicate in any considerable proportion or by itself in contact with the crude cottonseed oil containing such free fat't acids has a deleterious effect upon the co or, which necessitates the use of a larger percentage of sodium hydroxid in the subsequent treatment inorder to produce a refined oil of the desired color or it may be impossible to overcome the prejudicial effect on the color,-

: ing material. B this process, as has been cate on t explained such injurious effect of the sililie coloring, is prevented by first neutralizin the free fatty acids with the sodium hy roxid.-

To those skilled in this art it-will be clear that various minor changes may be made in the process outlined herein without departure from the substance of the invention or the sacrifice of any of its advantages.

In the particularprocessoutlined above the refining or purifyin seed oil has been referre to, but it is to be understood that the process is susceptible of satisfactory use in connection with many to the cotton-seed oil mentioned.

I claim: 1. The process of refining crude cottonseed oil and the like consisting in substantially neutralizing tli of crude cottons free fatty acids of the oil by caustic alkali, then treating the oil with a mixture of caustic alkali and a silicate, and separatin the refined oil from. the soap-stock forme substantially as described.

2. The process of refining crude cottonseed oil and the likeilconsisting in substantially neutralizing t e free fatty acids of the oil by an aqueous solution of caustic alkali, then treating the oil With a mixture of an aqueous solution of causticalkali and an aqueous solution of a silicate, and separatingthere'fined oil from the soap-stoc formed, substantially as described.

3. The process 0 refining crude cottonseed oil and the likeilconsisting in substan- 1 seed oil and the likeilconsisting in substantially neutralizing t efree fatty acids of the oil by a sodium hydroxid solution,then

subjecting the oil to a mixture of an aqueous solution of sodium hydroxid and an aqueous solution of sodium silicate, and separating the refined oil from the soap-stock or foots produced, substantially as described.

5. The process of refining crude cotton-' seed oil and the like having approximately 1% of free fatty acids, consisting in adding to the crude oil approximately 1% by weight of a sodium hydroxid solution, 18 Baum,

and agitating the same until the free fatty acids are substantially neutralized, then adding a mixture of approximately 8% by weight of the oil treated of an aqueous solution of sodium hydroxid, 18 Baum, and approximately of 1% by weight of the oil treated of an aoueous solution of sodium silicate, 44 Baum, agitating the mixture,

and slowly raising the temperature to approximately 115 Fahrenheit, and then separating the refined oil from the soap-stock produced, substantially as described.

GEORGE ,M. H'OLB'ROOK'.