USRE21498E

USRE21498E - Method of treating sugar melts

Info

Publication number: USRE21498E
Authority: US
Publication date: 1940-06-25

Description

June 25, 1940. D. v. wADswoRTH Er AL' R. 21,498

IETHQD 0F TREATING SUGAR MELTS Original Filed Sept. 27, 1929 Paw 5u ar aw Triad Wamgglggfafl Aad/faza (lll/W mi Ail @MI El @im Jaula/afd 'ranalafed 6064@ THEIR ATTORNEYS ReissuedvJune 25, 1940 UNITI-:D STATES PATENT OFFICE Daniel V. Wadsworth and Leonard Wickenden,

Manhasset, N. Y., assignors to John J. Naugle,

Greenwich, Conn.

Original No. 1,956,260, dated April 24, 1934, Se-

rial No. 395,521,

September 27, 1929.

Renewed 'July 12, 1933. Application for reissue March 3,

1936, Serial No. 86,970

BUlaims.

Our present invention relates to methods of treating sugar melts and syrups, particularly raw sugar melts, especially washed raw sugar melts,in such a way as to render the impurities present in such melts more readily adsorbable and such melts more readily lterable lthan where the same have been kept either in storage or transportatlon, or both, for considerable periods of time, and aims to devise methods of the general character especifled which are simple, which may be easily and conveniently practised and, which are highly successful for the designated purposes. Other objects and advantages of the methods of the present invention, particularly as exemplified in the following illustrative embodiments of the same, will in part be' pointed out in detail hereinafter and will in part be obvious to those skilled in the art to which the present invention relates.

In the accompanying specification we shall describe and in the annexed drawing more or less diagrammatically exemplify, several illustrative embodiments of the methods of the present invention. It is, however, to be clearly understood that our invention is not limited to the specic embodiments thereof herein described and more or less diagrammatically exemplified for purposes of illustration merely.

Referring to the drawing, in which we have more or less diagrammatically exemplified the aforesaid illustrative embodiments of the methods of the present invention, the single ngure of the same comprises a schematic arrangement of steps which may be followed in practising the aforesaid illustrative embodiments of the methods of the present invention.

Referring now to the aforesaid illustrative embodiments of thepresent invention, our starting or raw material is preferably raw sugar having an average polarization of from about 96 to about 97 degrees. Ordinarily we use raw cane sugar such as Cuban raw, although, of course, raw cane sugar from other sources, as from Puerto Rico, the Philippines, the Hawaiian Islands, Santo Domingo and Haiti may be used with equal success, as well as rawv sugars derived from other sources.

We now proceed to wash the raw sugar. This we may do in centrifugals in accordance with the practice hitherto prevailing. In these centrifugals the sugar is washed to a purity of about 99 degrees polarization. It may here be stated that the initial unwashcd raw sugars whose polarization is from about 96 degrees to about 97 degrees' containsQ in addition to the sucrose, in the case of sugar of 97 degrees polarization, for example,

about 1 per cent. of invert sugar, 'about 1/2 per cent. of ash, about 1 per cent. of organic impurities and about '/2 per cent. of water. 'I'he washed raw sugar on the other hand having a purity of about 99 degrees polarization, `contains about 1A, per cent, of invert sugar and organic impurities, about A per cent. ash and about 1/2 per cent. water. v

T'he result of the washing operation is therefore to obtain washed raw sugar of the designated purity and composition and the type of syrups known as afinations I'hese ailinations are preferably boiled in a vacuum pan to obtain raw sugar, the final by-product being molasses. The raw sugar obtained from boiling the aillnations is preferably mixed with the incoming raw sugar and Washed in the manner already indicated above.

'I'he next step of the operation is the melting of the washed sugar. This is preferably carried out in the following manner: We prefer to carry out the melting operation at a temperature of about degrees F. While the sugar may be melted in pure lhot water, We prefer to melt the same in hotmsweet water, that is, in water which contains some sugar values, as the sugar values derived by treating the purifying and flltering media subsequently described to remove the last traces of sugar therefrom.

In conducting the-melting operation we prefer that the water used for melting, whether ordinarywater or sweet water, shall be substantially free from iron. For this purpose we may treat either the ordinary water or the sweet water with a suitable reagent, such as a solution of disodium phosphate, to precipitate the iron which may afterwards be removed by decantation or filtration, as desired. We prefer also to treat the ordinary or "sweet water with an agent which will tend to raise its pH and thus lower the hydrogen ion concentration both of the water used for melting and of the resulting melt.

Accordingly, we use a slight excess of disodium phosphate, which reagent will therefore serve not only to precipitate iron, but also to raise the pH reading and thus lower the hydrogen ion concentration.

Where, as is preferred, sweet for melting-the washed raw sugar, the amount of disodium phosphate used, both for precipitating iron and for increasing the pH reading and thus for lowering the hydrogen ion concentration may range from about 20 to about 50 pounds of the crystalline disodium salt` per 2000 gallons of "sweet or other water used for the melting procwater is usedl ossgfmsfwouid correspond to from about a toy about sopouuds of the anhydrous salt per zooo gallons of sweet" or other water used for the melting operation.

i g We `prefer that the density of the resulting melt shall be about 60 degrees Brix. more or less. The temperature ofthe hot melt will shortly fall to about 100 degrees F. It may here be stated, that we prefer that after the temperature of the l. melt has been stabilized at about 100 F., it shall for this purpo, we prefer to use a chlorine generating agent, in the form of an aqueous solu- I tion. Ordinarily, however, we use a ,hypochlorite, preferably a hypochlorite of one of the alkali or alkaline earth metals, such as calcium hypochlorite, preferably in the form of "bleach liquor.

Invtreating the melt with the calcium hypoil chlorite solution or equivalent agent, we may proceed substantially as follows to produce a substantially colorless product:

Assuming that bleach liquor is the agency to be employed, the bleach liquor for this purpose a may be prepared from solid calcium hypochlorite or chloride of lime by stirring the solid with water until all of the soluble matter present has gone into solution. ".l'he clear solution thus obtained may now be decanted from `the insoluble l matter. 'I'he proportions used in making the liquid may be vabout pounds of chloride of lime and about 40 gallons of water. About 18 `gallons of the clear liquor may be run through a -pipe to the bottom of the tank containing about U 3000 gallons of say degrees Brix melt. Thisl will correspond, for example, to about 19,600 pounds of sugar solids in solution. During this time the average temperature of the melt may be kept at about normal temperature correll spondingto about or 80 degrees F., although higher temperatures may if desired be employed. The mixture of melt and bleach liquor will be agitated and vthen permitted to stand for about l5 minutes in order to permit the action to be l0A completed. At this point any calcium orv iron present in the melt may again be precipitated by the addition of a mixture of mono-sodium and disodium phosphates or by the addition of these phosphates separately or alone. For example, Il to about 3000 'gallons of melt at a density of about 60 degrees Brix may be added about 371/2 pounds of disodium phosphate in the crystalline condition, corresponding to approximately 14% pounds of anhydrous disodium phosphate and N about 11% pounds of the monosodium phosphate which is used in the form of the solid. During and after a brief period after the addition of the -monosodium and disodium phosphates or their equivalents, the melts are briefly and vigorously w agitated. After theprecipitation, corresponding to a defecation oi' the melt, is completed, the agitation may be stopped for a period sumcient to permit the precipitates tc agglomerate and settle. As a result of this treatment, the melt 7 is' substantially bleached, or deoolorized, und

sterilized, and the impurities are readily adsorbable and iilterable.

The treatment described above may be repeated several times, after which the melt may be further reiined or decolorized. For this purpose its concentration is reduced,l as to about 50 to 60 degrees Brix so as to facilitate the illtering and decolorizing operations. The melt, now of reduced concentration, is subjected to a treatment with a purifying and iiltering medium as with a suitable amount of a decolorizing carbon, preferably a decolorizing carbon of vegetable origin, such as the highly activated decolorizing carbon known to the trade as Suchar.

Ordinarily, where "Suchar" is used, we use an amount of Sucher equal to about 2 per cent.

of the weight of the sugar solids present in the melt. 'Ihe mixture of melt and suspended carbon is thoroughly agitated in a tank. the melt being preferably heated to and maintained at a temperature of from about to about 200 degrees F., as about or 190 degrees F. 'I'he mixture of melt and suspended carbon is now pumped into a suitable illter, such as the wellknown type of "au iilter. The clear melt coming from the iilter is run through a bag iilter and then through a felt and paper filter to a 'storage tank. From the storage tank it may run into an evaporator, where as is usual, it is desired to increase its density or concentration as to about 37 degrees Baum corresponding to about 68 degrees Brix.

The concentration of the syrup preferably takes place under vacuum, the temperature being about 110 degrees F. or less. In those cases where the pH reading is corrected in the evaporator it is desirable to add trisodium phosphate or its equivalent to the syrup when its density has been raised to about 62 degrees Brix.

Where, instead of a refined, substantially color- 5 less syrup, it is desired to produce rened or granulated sugar directly from the sterilized melt after it reaches its destination, the desired result may be effected by treating the melt with about 1% to about 2 per cent. of Suchar or equivalent decolorizing carbon based on the weight of the sugar solids contained in the melt. In other words, the melt, the density of which has in this case also preferably been reduced to about 50 degrees Brix.- may be treated with carbon in the amounts already indicated. The purified melt so obtained is sent to the evaporating pans where it is evaporated and refined or granulated sugar obtained by crystallization under vacuum, four or ve strikes of sugar being so obtainable, the various strikes of sugar being mixed or blended together in the production of the refined or granulated sugar which will often be of standard or even superior purity and quality.

This completes the description of the aforesaid illustrative embodiments of the methods of the present invention. It will be noted that such methods are simple, may be easily and conveniently practised and have the numerous advantages and economies setforth in detail above. It will be noted that a melt of the desired density, hydrogen ion concentration and sterile qualities is obtained. From such melt, by means of the methods of the present invention, refined or substantially colorless Syrups may readily be obtained in an altogether simple and economical manner. From such melts may also be obtained refined or granulated sugar of standard or even superior qualities in an altogether simple and eil'ective manner. Other superiorities and advantages of the methods of the present invention and of the resulting products, particularly as exemplified in the aforesaid illustrative embodiments of the same, will readily occur to those skilled in the art to which the present invention relates.

It may here be stated that throughout the specication and claims, wherever the term melt" is used, said term is intended to include also syrups of any desired degree of concentration, unless a contrary meaning is indicated.

What we claim as our invention is:

l. In the method of treating a sugar syrup or melt to produce a substantially colorless product, the improvement which comprises treating washed sugar with an agent of the group consisting of chlorine and the hypochlorites, then with a phosphatic defecating agent, and thereafter adding to theliquid so treated a decolorizing-and filtering carbon.

2. In the method of treating a sugar syrup or melt to produce a substantially colorless product, the improvement which comprises treating washed sugar with a hypoehlorite, then with a phosphatic defecating agent, and thereafter adding to the liquid so treated a decolorizing and iiltering carbon.

3. In the method of treating a sugar syrup or melt to produce a substantially colorless product, the improvement which comprises treating washed sugar with calcium hypochlorite, then with a phosphatic defecating agent, and thereafter adding to the liquid so treated a decolorizing and filtering carbon.

4. In the method of treating a sugar syrup or melt to produce a substantially colorless product, the improvement which comprises treating washed sugar with an agent of the group consisting of chlorine and the hypochlorites, then with one of the phosphates of sodium, and thereafter adding to the liquid so treated a vegetable decolorizing and filtering carbon.

5. In the method of treating a sugar syrup or melt to produce a substantially colorless product, the improvement which comprises treating washed sugar with a hypochlorite, then with one of the phosphates of sodium. and thereafter adding to the liquid so treated a vegetable decolorizing and filtering carbon.

6. In the method of treating a sugar syrup or melt to produce a substantially colorless product, the improvement which comprises treating washed sugar with calcium hypochlorite, then with one of the phosphates of sodium, and therealt-er with a purifying carbon.

DANIEL V. WADSWORTH. LEONARD WICKENDEN.