US3401059A

US3401059A - Manufacture of sugar

Info

Publication number: US3401059A
Application number: US427513A
Authority: US
Inventors: John A Casey
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-01-22
Filing date: 1965-01-22
Publication date: 1968-09-10
Anticipated expiration: 1985-09-10
Also published as: IT1048378B; GB1061698A

Description

United States Patent 3,401,059 MANUFACTURE OF SUGAR John A. Casey, Pepper Pike, Ohio (2804 Brainard Road, Cleveland, Ohio 44124) No Drawing. Filed Jan. 22, 1965, Ser. No. 427,513 Claims. (Cl. 127--61) ABSTRACT OF THE DISCLOSURE A solution of dioctyl sodium sulfo-succinate is added to the sugar juice, for example, to the vacuum pans during the boiling of the massecuite to reduce the boiling time and improve the crystallization of the sugar and the separation of the molasses from the sugar.

This invention relates to the manufacture of sugar and more particularly to improvements in the crystallization of sugar from sugar-containing solutions as carried out in sugar mills and refineries. The invention is described herein as applied to the production of cane sugar, but it is to be understood that it may also be used in the production of other kinds of sugar, such as beet sugar.

In a typical sugar mill, the juice is first extracted from the cane, lime is added to control the pH, the juice is heated, and then it goes to a clarifier in which the precipitates formed by the action of heat and lime are eliminated to as great a degree as possible. The clarified juice then travels to a series of evaporators or a multiple effect evaporator where the juice is concentrated from an entering concentration of about or 16% of sugar to a syrup having a concentration of about 65% sugar. The syrup from the evaporators then proceeds to vacuum pans where further evaporation is accomplished by boil ing the syrup under reduced pressure. The syrup is evaporated in vacuum pans until it becomes a saturated or super-saturated solution of sugar. The syrup is then seeded to initiate crystal growth and when an evaporator pan has become filled with a fairly dense mixture of crystals and syrup known as massecuite, the contents of the pan, called a strike, is discharged. The strike is normally cooled, with slow mixing, in a crystallizer to permit additional extraction of sugar from molasses to crystals as the mass cools. The mass is then centrifuged to separate the sugar crystals from the molasses.

In most sugar factories, the three-boiling system is employed. The first boiling of pure syrup yields what is known as A sugar and A molasses. The A molasses with a footing of sugar crystals and some syrup is reboiled to provide a second massecuite which in turn provides what is called a B strike that provides B sugar and B molasses. The operation is again repeated with the B molasses and a footing of sugar crystals and syrup. The strike is called a C strike and the crystallization operation then produces C sugar and C molasses, which is the final or blackstrap molasses. The amount of sucrose in the C molasses is a measure of the efficiency of the extraction process. The smaller the percentage of sucrose in the C molasses, the more efiicient the process. Also, the

smaller the amount of C, or final molasses that is produced for a given amount of sugar juice, the more efficient the process. Ordinarily, the A and B sugars are sold, while the C sugar is used for seeding.

Various known steps are taken to improve the eificiency of the process and to extract as much of the sugar as possible from the molasses. Also, certain compounds have been added to the sugar syrup before the crystallization of the sugar in an effort to improve the quality of the sugar and to increase the percentage of crystalline sugar obtained from the juice. See for example, US. Patent No. 2,871,148, issued Jan. 27, 1959.

3,401,059 Patented Sept. 10, 1968 The general object of the present invention is to provide an improved method of crystallizing sugar whereby the yield of sugar is increased, the quality of the sugar is improved, the boiling time required in the evaporators is substantially reduced, and the operation of the centrifuges is improved as compared to conventional methods and materials presently in use in the crystallization of sugar. Another object is the provision of a composition of matter suitable for use in carrying out this process.

According to the present invention, the foregoing ad vantages are obtained at reasonable cost by adding to the sugar juice, syrup or massecuites a very small amount of a water soluble salt of a sulfo-succinate ester wherein the ester groups are water insoluble, such as dioctyl, dihexyl, di-isobutyl or ditridexyl. Sodium, potassium or ammoni um salts may be used, the sodium salt being preferred from the standpoints of cost, availability and effectiveness. The preferred compound is dioctyl sodium sulfosuccinate. However, dihexyl, di-isobutyl and di-tridecyl sulfo-succinates may also be used, although with slightly less improvement than is obtained with dioctyl sodium sulfo-succinate. The material may be added to the vacuurn pans, to the crystallizers or to the evaporators before the vacuum pans. It may be added to the juice at an earlier stage but it should not be added at a stage where lime is present to an extent sufficient to react with the material to produce a relatively insoluble calcium salt. Preferably, the material is added to the pans during boiling of the massecuites, although it may also be added advantageously to the crystallizer as the strike is discharged to the crystallizer.

The amount added depends largely upon the concentration of sugar at the point of the process at which the material is added. Preferably, the material is added at a rate of from to part by weight of dioctyl sodium sulfo-succinate per million parts of juice, syrup or massecuite, per 1 percentage point of sucrose in the juice, syrup or massecuite by weight. For example, in juice containing 15% sucrose, 1.5 to 7.5 ppm. of dioctyl sodium sulfo-succinate are added. In massecuite containing sucrose, 8 to 40 ppm. of dioctyl sodium sulfo-succinate are added. The amount of material added is not critical so long as enough is added to obtain the desired results. Amounts above the upper limits given do not substantially improve the results as compared to amounts within the range set forth and it is therefore uneconomical to exceed the upper limits. When amounts below the lower limits are employed, optimum results ordinarily cannot be obtained. The amount selected within the ranges given depends upon the quality of the syrup, high quality, wellclarified syrup requiring less of the material for optimum results than syrup that contains more impurities. From the standpoint of cost, it is desirable to avoid use of excess amounts of the material, but this is not a factor of great moment since the benefits accruing from the use of the process are in most instances worth several times the cost of the material, even when amounts of material in the upper part of the preferred range are employed.

Preferably, the material is added in the form of a solution consisting of 50% by weight of dioctyl sodium sulfosuccinate, 25% by weight ethyl alcohol and 25 by weight water, or 50% by weight dioctyl sodium sulfo-succinate, 25% by weight propylene glycol and 25% by weight water. Each of these is a free-flowing solution that can be added to the syrup with little difficulty and that rapidly disperses in the syrup. Dioctyl sodium sulfo-succinate in undiluted form is a waxy solid that would be diificult to handle and disperse in the syrup without special equipment, and in addition, tests have shown that the presence of a small amount of ethyl alcohol or propylene glycol, or both, in the syrup results in an improvement in the process as compared to the use of dioctyl sodium 3 sulfo-succinate alone, probably because of dispersion of the dioctyl sodium sulfo-succinate in the syrup. The amounts of water, ethyl alcohol and/ or propylene glycol can be varied substantially from those given above, and a that the sugar crystals are of improved quality, and that they are drier and whiter when they leave the centrifuge. Observation also shows that the boiling in the pan is more uniform and more easily controlled, and that the molasses is less viscous and easier to handle.

mixture of ethyl alcohol and propylene glycol can be used 1f deslred. However, I prefer that the weight of ethyl As noted above, foregoing results were obtained with alcohol, propylene glycol or mixture of the two be about the preferred solution consisting of 50% dioctyl sodium /2 the weight of the dioctyl sodium sulfo-succinate pressulfo-succinate, 25% water and 25% ethyl alcohol. Preent 1n the solution. liminary tests with propylene glycol in place of ethyl alco- The following table indicates the nature of improve- 1101 indicate even greater improvement. Tests without the ment obtained in tests conducted in five sugar factories. ethyl alcohol show slightly less improvement than the Tets identified by the same letter were made in the same tests given above, but the results are nevertheless remarkfactory, and in each factory the tests with the treatment able. I have not tested the other soluble salts of sulfoaccordlng to the present invention immediately followed succinates listed above in sugar factories, but laboratory the tests without the treatment so as to minimize possible tests with sucrose solutions indicate that these materials effects of other variables. All tests involved C sugars. The are also eifective in reducing viscosity and surface tension, additive, when used, consisted of by weight dioctyl although not to as great a degree as the preferred dioctyl sodium sulfo-succinate, 25% by weight water and 25% sodium sulfo-succinate. by weight ethyl alcohol. The amounts given are parts per The invention is also useful in the refining of sugar in m1ll1on by weight of dioctyl sodium sulfo-succinate in 20 sugar refineries where sugar from the factories is disthe massecuites; the parts per million of the solution were solved and then recrystallized to purify it, and as noted double the amounts given in the table. above, in the production of other sugars, such as beet Average Apparent Approx. No. of boiling Percent purity of percent Additive strikes time per decrease final in low Test No. (p.p.m.) in test strike in boiling molasses grade (minutes) time (percent sugar sucrose) recovered (percent) 6 134 12 116 4 9e 13 213 e 165 11 No data 9 No data 10 No data 10 No data From the foregoing, it will be seen that in factory A, the boiling time was reduced 35.3%; in factory B, the reduction of boiling time was 17.5%; and in factory C, the boiling time was reduced 22.6%. This reduction in boiling time gives, in effect, a corresponding increase in the productive capacity of the pans without requiring any increased capital investment. Furthermore, the reduction in boiling time reduces fuel costs, and reduces the degradation of sucrose that takes place continually at low rates due to elevated temperatures in the pans. The boiling time apparently is reduced by reason of the reduced viscosity and reduced surface tension of the syrup. The reduced viscosity evidently increases the rate of circulation of the syrup within the pan, eliminates local hot spots in the pan and possible degradation of the sugar crystals because of hot spots, and also makes it possible to charge a given pan with a greater amount of syrup.

The reduced viscosity also improves the crystallization and facilitates the separation of the molasses from the sugar crystals in the centrifuges. This is evidenced by the foregoing tests which show a reduction in the percentage of sucrose contained in the molasses, thus indicating a corresponding increase in the percentage of sugar crystals obtained from the juice. As the table shows, in the four factories where data on this point were obtained, the improvement ranged from 1.3% to 3.7%.

The reduction in boiling and the general improvement in the boiling operation resulting from the use of the present invention reduce the amount of degradation of the sucrose that takes place in the pans as compared to prior practice, and this reduces the amount of final molasses that is produced for a given quantity of sugar juice, thus further increasing the yield. Quantitative data relating to this factor are not available at the present time, however.

In addition to directly measurable improvements, the improvement obtained by the process of the present invention is readily apparent to the sugar boiler. From observation of the process and of the massecuites at various stages of the process, the boiler immediately recognizes sugar, facilitating the concentration of the sugar syrup in the pans, the crystallization of the sugar and the separation of the crystals from the molasses.

I claim:

1. A process of crystallizing sugar from a sugar-containing solution which includes the step of adding to the sugar-containing solution a water soluble salt of a sulfosuccinate ester wherein the ester groups are insoluble.

2. A process according to claim 1 wherein the salt is a material from the group consisting of dioctyl sodium sulfo-succinate,

dioctyl potassium sulfo-succinate,

dioctyl ammonium sulfo-succinate,

di-isobutyl sodium sulfo-succinate,

di-isobutyl potassium sulfo-succinate,

di-isobutyl ammonium sulfo-succinate,

dihexyl sodium sulfo'succinate,

dihexyl potassium sulfo-succinate,

dihexyl ammonium sulfo-succinate,

di-tridecyl sodium sulfo-succinate,

di-tridecyl potassium sulfo-succinate,

di-tridecyl ammonium sulfo-succinate.

3. A process according to claim I wherein a material from the group consisting of ethyl alcohol and propylene glycol is added to the sugar-containing solution along with the said salt.

4. In the process of crystallizing sugar, the step which comprises carrying out the crystallization in the presence of dioctyl sodium sulfo-succinate.

5. A process according to claim 4 wherein the dioctyl sodium sulfo-succinate is present in the amount of from about to /2 part by weight of dioctyl sodium sulfosuccinate per million parts by weight of the material from which the sugar is crystallized per 1 percentage point by weight of sucrose in said material.

6. In a process of crystallizing sugar from a sugar-containing solution in which the sugar-containing solution is concentrated in an evaporator, further concentrated in a vacuum pan, crystallized in a crystallizer and then centrifuged to separate the sugar crystals from the remainder of the solution, the improvement which includes the step of adding dioctyl sodium sulfo-succinate to the sugarcontaining solution in the amount of about to /2 part by Weight of dioctyl sodium sulfo-succinate per million parts by weight of solution per 1 percentage point of sucrose by Weight in the solution.

7. A process according to claim 6 wherein the dioctyl sodium sulfo-succinate is added to the solution before it reache the evaporators.

8. A process according to claim 6 wherein the dioctyl sodium sulfo-succinate is added to the solution in the evaporator.

9. A process according to claim 6 wherein the dioctyl sodium sulfo-succinate is added to the solution in the vacuum pan.

10. A process according to claim 6 wherein the dioctyl sodium sulfo-succinate is added to the solution as it is discharged to the crystallizer.

References Cited UNITED STATES PATENTS 2,871,148 1/1959 Kent 127-58 2,591,704 4/1952 King 12758 FOREIGN PATENTS 760,121 10/1956 Great Britain.

OTHER REFERENCES Moritsugu, T., Effect of Pan-Aid etc., item 418 on p. 102 of Sugar Industry Abstracts, published by Tate & Lyle, Ltd., vol. 28, No. 6, June 1966.

MORRIS O. WOLK, Primary Examiner.

D. G. CONLIN, Assistant Examiner.