US2871148A

US2871148A - Crystallizing of sugars

Info

Publication number: US2871148A
Application number: US650302A
Authority: US
Inventors: Sheldon E Kent
Original assignee: Hodag Chemical Corp
Current assignee: Hodag Chemical Corp
Priority date: 1957-04-03
Filing date: 1957-04-03
Publication date: 1959-01-27
Anticipated expiration: 1976-01-27

Description

n ta es mfl No Draw-ing. Application April 3, 1957 Serial No. 650,302 I 7 Claims; ci; 127 -58)" y invention isdirecte'd to improvements in the crystallization'ofsu'gars. I

In the usual process of crystallizing' beet sugar (the process may vary somewhat in the case of crystallizing cane sugar "and corn sugar) thesugarliquors' (at certain stages called the filmass), which comprise the sugar proper andthe molasses and various other impurities from which the sugar is to be separated by crystallization, and hereafter referred to as the syrup for convenience, are passed through so-called crystallizers, raw vacuum pans and intermediate pans where various heating and evaporation procedures are elfected until ultimately crystalline sugar and molasses are obtained, the latter commonly being pumped into storage or shipping tanks.

I have found that if there is admixed with the syrup small proportions of certain compounds, hereafter de scribed, prior to effecting crystallization of the sugar, various important advantages are obtained. One of these advantages is an increase in the percent of crystallization or, in other words, an increase in the yield of the crystalline sugar, and the purity thereof. Another advantage is improvement of spinning performance in the centrifuge. A further advantage is the reduction in the amount of entrained air in the separated molasses and the purity of the molasses.

The compounds the utilization of which in the environment to which my invention relates are fatty acid esters of glycosides, the fatty acid acyl radicals of which contain from 8 to 22 carbon atoms and especially from 12 to 14 carbon atoms. Of particular utility are the fatty acid di-esters of methyl glueoside, especially those in which the fatty acid acyl radical contains predominately from 12 to 14 carbon atoms as may be derived, for instance, from coconut oil, coconut oil mixed fatty acids or, fractions thereof containing mainly lauric or lauric and myristic acids. These glycoside esters are fully disclosed and methods for their preparation described in United States Letters Patent Nos. 2,759,922 and 2,759,923, both patented August 21, 1956.

The glycoside esters may be added at any one or more stages of the process as, for instance, in the raw vacuum pans, when charged, or in the intermediate pans when charged, or in the crystallizer when the latter is charged, or in whole or in part at any of said stages or other stages. For best results, the glycoside esters should be thoroughly or intimately mixed with the syrup. It is particularly desirable, therefore, that the glycoside esters be intimately admixed with the syrup directly when the latter is charged to the raw vacuum pans since this results in an enhancement of the intimacy of admixture due to the longer agitation during the various stages up to and including the crystallization of the sugar.- From the intermediate pans a part of the glycoside esters goes forward with the sugar but, generally, passes on to the raws and then to the molasses.

The proportions of the glycoside esters utilized are variable although always on the small side. Thus, for instance, good results are obtained by adding to 20 Z pounds of coconut oil mixed fatty acid di-estersof. methyl glucos'ide to the crystallizer in a beet sugar operation when 60,000 pounds of'syrup are=charged to said crystah lizer; or by adding 10 to 20 pounds of said esterstothe raw vacuum pans when the latter are charged with 60,000 poundsof syrup; or by adding 10 to 20 pounds of said esters to the raw pans-when chargedwith 60,000 pounds of syrup and by adding 8 to 12 pounds of said esters when the syrup is charged to the intermediate pans; or by adding '8 to 12 pounds of said esters to the intermediate pans when the latter are chargedwith 60,000. pounds of syrup from the raw vacuum pans. It will be understood that these proportions are merely illustrative. The amounts are variable, as indicated, and will depend, in part, on the particular glycoside esters or mixtures thereof utilized, upon the extent to which optimum results are sought, upon theparticular stage. at which the glycoside esters are added in the process, and upon the particular type of sugar being crystallized, Thus, for-instance, in general, greater percentages are used with corn sugar than with beet sugar. In general, the proportions of glycoside est rs will range from as low as about 0.01% .to as high as about"2%, and preferably from 0.03% to 1.5%, by

weight of the charge.

In actual tests on a plant scale, the percent of crystallization of beet sugar without the practice of my invention amounted to 58.5% whereas, by the practice of my invention, in the manner described above, the percent of crystallization increased to 59.5% and higher. The increase in the percent of crystallization may vary from of the order of 0.5% to as much as 3% or 4%, depending on the various factors discussed above. The following table is illustrative of various of plant scale tests in the crystallization of beet sugar:

N 0. of Strikes Average in Determin- Percent Treatment (with coconut oil Test No. ing Percent Crystallizafatty acid di-ester of methyl Orystallization glucoside) tion 13 58. 5 None. 30 59. 5 121; in crystallizer. 32 60. 8 12# in raw pans. 11 60.7 6# in intermediate and 12# in raw pans. 9 61.4 8# lntntermediate pans. 14 60.3 None. 14 60. 6 8# in intermediate pans.

Over and above and independently of the advantage of increases in yields of sugar in the crystallization step, the use of the glycoside esters also serves very effectively to reduce the entrainment of air in the by-product molasses. Air entrainment by the molasses is highly objection-- able because it causes the apparent density of the molasses to be lowered to a point where it is difficult to make minimum weights for tank car and tank truck shipments. It also causes pumping difliculties while filling storage tanks and emptying cars and reduces storage capacity by as much as 30% to 40%. By the addition of the glycoside esters in accordance with my invention, this problem is very effectively overcome. The quality of the molasses is enhanced and a considerably more salable product is obtained. The improvement in molasses quality in the aforesaid regards is greater at Brix values of 82 to 83 than at Brix values of 84 and higher but in all cases is pronounced.

While the glycoside esters can be used as such in the practice of my invention, it is within the scope of my invention to use the glycoside esters in the form of mixtures thereof with a carrier or diluent as, for instance, triglyceride oils, notably vegetable oils such as cottonseed oil, corn oil, soya oil, etc., or mineral oils, or methyl esters of triglyceride oil fatty acids. Furthermore said glycoside esters, as such or admixed with said diluents or carriers, can be used in admixture with emulsifiers such as higher fatty acid monoglycerides, and polyoxyethylene glycol esters of higher fatty acids such as polyethylene glycol (400) mono-oleate, to obtain the known. added advantages of said emulsifiers.

What I claim as new and desire to protect by Letter Patent of the United States is: I Y

1. In the process of crystallizing sugars, the step which comprises carrying out the crystallization in the presence of a fatty acid ester of a glycoside, the fatty acid acyl radical of said ester containing from 8 to 22 carbon atoms.

. 2. In the process of crystallizing beet sugar, the step which comprises carrying out the crystallization in the presence of a fatty acid ester of a glycoside, the fatty acid acyl radical of said ester containing from '8 to 22 carbon atoms. r

3. In the process of crystallizing sugars, the step which comprises carrying out the crystallization in the presence of a fatty acid di-ester of methyl glycoside, the fatty acid acyl radical containing from 8 to 22 carbon atoms.

4. In the process of crystallizing sugars, the step which comprises carrying out the crystallization in the presence of a fatty acid di-ester of methyl glucoside, the fatty acid acyl radical containing predominately from 12 to 14 carbon atoms.

5. In the process of crystallizing sugars, the step which comprises intimately admixing a sugar syrup, prior to crystallization of the sugar therefrom, with from 0.01% to -2%, by weight, of a fatty acid ester of a glycoside, the fatty acid acyl radical of'said ester containing from 8 to 22 carbon atoms.

6. In the process of crystallizing beet sugar, the step which comprises intimately admixing beet sugar syrup, prior to crystallization of the sugar therefrom, with from 0.3% to 1.5%, by weight, of a fatty acid di-ester of methyl glucoside, the fatty acid acyl radical containing predominately from 12 to 14 carbon atoms.

7. In the process of crystallizing corn sugar, the step which comprises intimately admixing corn sugar syrup, prior to crystallization of the sugar therefrom, with from 0.3% to 2%, by weight, of a fatty acid di-ester of methyl glycoside, the fatty acid acyl radical containing predomi- 20 nately from :12 to 14 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 700,099 Spreckels et al May 13, 1902 King Apr. '8, 1952

Claims

1. IN THE PROCESS OF CRYSTALLIZING SUGARS, THE STEP WHICH COMPRISES CARRYING OUT THE CRYSTALLIZATION IN THE PRESENCE OF A FATTY ACID ESTER OF A GLYCOSIDE, THE FATTY ACID ACYL RADICAL OF SAID ESTER CONTAINING FROM 8 TO 22 CARBON. ATOMS.