MXPA01006901A - Neutral phosphate pre-coagulant composition for clarificationin white sugar production - Google Patents

Abstract

Methods and compositions for clarifying sugar are disclosed. Compositions of a condensation polymer of a dihaloalkyl compound and a dialkylamine compound and a phosphate compound are effective at clarifying the sugar syrup during its production as well as reducing the total amount of phosphate used.

Description

NEUTRAL PRE-COAGULANT COMPOSITION OF PHOSPHATE FOR CLARIFICATION IN THE PRODUCTION OF WHITE SUGAR FIELD OF THE INVENTION The present invention provides the methods and compositions for clarifying sugar solutions while reducing the amount of the phosphate-based compound that is employed.

BACKGROUND OF THE INVENTION After the sugar is extracted from the prepared cane, the resulting mixed juice (water, sucrose and other impurities) needs to be clarified. In the production of white sugar, this clarification is important in view of the fact that the better the clarification of the sugar juice, the better the final (ie whiter) sugar will be. The coagulation of the impurities in this current is very important to obtain a good final product. After the clarification stage, the evaporation stage takes place. Any impurities present that cause color problems in the liquid are also concentrated in the same proportion as the sugar juice does. In this stage color levels of up to 6000 to 10000 ICUMSA color units are usually obtained.

As such, a large number of sugar mills will clarify the sugar syrup after the evaporation step. This process is usually carried out by pre-coagulating the sugar syrup and passing it through a flotation system. If phosphoric acid is used as the phosphate source in the pre-coagulation step, calcium or calcium saccharate is used to neutralize it and maintain the pH of the sugar syrup in the neutral range to avoid inversion of the sugar. This neutralization step can be a complicated operation due to the solids content. The sugar syrup can have 60 to 70% solids content and these can be deposited on the electrodes of the pH meter reducing their sensitivity and causing variations in the pH. These variations in pH can cause the color of the clarified syrup to be greater than before the clarification step. This substantially compromises the quality of the final sugar. Additional complications arise due to the high concentration of sugar syrup. This high concentration makes the calcium dissolution slow and the pH adjustment will take longer. This slow response will cause an overfeeding of calcium saccharate which in turn will cause an increase in pH at different levels from the correct one and will lead to a high color and high ash content in the final sugar product. Other difficulties may arise when this syrup then passes to the evaporation systems. These systems are usually a series of containers each of which has a greater vacuum than the previous one.

This process will concentrate the sugar juice even more. The use of phosphoric acid and other phosphate compounds in the clarification stage can cause incrustation problems in the evaporation stage. The high phosphate concentration, when concentrated even more in the evaporation stage, can crystallize and precipitate causing deposition in the evaporation stage. The present inventors have discovered a novel pre-coagulant composition that reduces the amount of phosphate that is employed and reduces the amount of flake formed in the evaporation step of the sugar manufacturing process.

DETAILED DESCRIPTION OF THE INVENTION The present invention offers an improved process for clarifying sugar syrup during sugar production. The method consists in adding an effective amount of a compound containing a condensation polymer and a phosphate compound to the sugar syrup during the pre-coagulation. The condensation polymer comes from the condensation polymerization of epichlorohydrin and an alkyl dihalo compound with a dialkylamine, wherein the alkyl groups of the dialkylamine have from 1 to about 5 carbon atoms. Exemplary dialkylamines include dimethylamine, diethylamine, dipropylamine, dibutylamine and dipentylamine. Preferably, the dialkylamine is dimethylamine or diethylamine. A preferred embodiment of this polymer can be obtained from the condensation polymerization of epichlorohydrin with dimethylamine, with a molecular weight from about 8,000 to about 14,000. Representative phosphate compounds include, but are not limited to, halogen salts such as phosphorus trichloride.; tripolyphosphates, pyrophosphates, hexametaphosphates and trisodium phosphates. Any phosphate salt that is soluble in water and does not substantially lower the pH of the sugar syrup is expected to be within the scope of this invention. Preferably, the phosphate-based compound is food-grade sodium tripolyphosphate such as those commercially available from Monsanto as NUTRIPHOS 0-88 and Albright and ilson as ALBRIPHOS 50F.

The method of inventiveness takes place in the flotation or clarification system of the sugar clarification system. The sugar syrup goes into the flotation system, where the sugar syrup coagulates or pre-coagulates before the syrup goes through the crystallization phase of the white sugar production process. Sugar syrup can be defined as a colloidal suspension composed of different types and sizes of particles. Table A illustrates the general composition of this syrup according to the particle diameter.

TABLE A Dispersion Diameter (μ) Weight Types Raw D > 1 2-5 Small particles of bagasse, Colloidal sand 0.00KEK1 0.05-0.3 Waxes, fats, proteins, gums, dyes, Molecular dextrans D < 0.001 8-21 Sugars: sucrose, glucose, and ionic fructose, mannose Mineral salts: sulfates, chlorides, silicates and phosphates of K, Ca, Mg and Na Organic acids: aconitic, oxalic, alic, etc.

The coagulation of these impurities is important to obtain the finished product of white sugar finished. According to Stoke's law, the tendency of the particles to coagulate is inversely proportional to the square of their diameter. Since 8 to 21% by weight of the sugar syrup juice is composed of particles smaller than 0.001 microns, the process of coagulating the juice of the sugar syrup does not follow Stoke's law, but is directed by the Zeta potential . The Zeta potential is the electrical charge acquired by a particle in a liquid suspension. The closer to zero this potential is, the better the coagulation will be. Table B illustrates the stability characteristics against the Zeta potential.

TABLE B Stability characteristics Zeta potential (mV) Agglomeration and maximum precipitation +3 to 0 Agglomeration and excellent precipitation +1 to -4 Agglomeration and weak precipitation -5 to -10 Very weak agglomeration -11 to -20 Weak stability (only some agglomerates) - 21 to -30 Moderate stability (no agglomerates) -31 to -40 Good stability -41 to -50 Very good stability -51 to -60 Excellent stability -61 to -80 Maximum stability -81 to -100 For purposes of the present invention , the phrase "effective clarifying amount" is defined as that amount of the condensation polymer and the phosphate compound that will clarify the sugar syrup. Preferably, it ranges from about 50 parts of the composition to about 250 parts per million parts of the sugar syrup. The weight ratio of the condensation polymer to the phosphate compound is generally in the range of about 10 to about 5 with a preferred weight ratio of about 2 to about 1. The composition of the invention can be added to the sugar syrup as a combination or as individual ingredients. Preferably, the composition is added to the sugar syrup before its arrival in the flotation system, but it can also be added to the syrup in the flotation system. The invention will now be described with reference to different specific examples, which should not be considered as limiting the scope of the claimed invention.

Examples Tests were performed to measure calcium reduction using neutral phosphate sources compared to phosphoric acid. 200 ml of sugar syrup were transferred to a 500 ml beaker. The syrup had a density of 1.085 g / cm3, a brix index of 21.5, an original ICUMSA IV number of 9182 and a pH of 5.0 The temperature of the sucrose test device was first adjusted to 85 ° C and mixed strongly for about 5 minutes . Then the syrup was transferred to the graduated tube for the sugar test while the anionic polymer solution was added at the same time. The tube was then capped and agitation and air injection at 65 to 70 rpm were started for one minute. The size of the flakes formed and the rate of flotation were observed. After 20 minutes, a sample was taken and diluted to 10 ° brix. This sample was filtered through a Millipore membrane of 47 μ in vacuum. At 420 nm wavelength the absorbance and transmittance of the filtered sample were measured. ICUMSA IV color is calculated using the formula: Absorbance x 1000 Color ICUMSA IV Brix / 100 x density x width of the cuvette where: Density = density of the sample of diluted syrup, filtered Brix = brix of the diluted and filtered syrup sample Width of the cuvette = 1.0 cm The results of this test are presented in Table I. The higher the percent of transmittance, the better the clarification of the syrup.

TABLE I Clarification of the sugar syrup pH = 7 at 100 ° C Without S02 oxidant Test Calcium Pre-Coagulating ABS Trans Color ICUMSA (ml / 1) anionic coagulant (ppm) (420 nm) (%) IV (ppm) 1 5.5 2.0 0.6070 24.7 5848 2 4.2 A (50) 2.0 0.5310 30.6 5116 3 4.0 B (250) 2.0 0.4535 35.8 4369 The pre coagulant A is sodium tripolyphosphate The pre-coagulant B is 20% dimethylamine-epichlorohydrin copolymer and 10% by weight sodium tripolyphosphate, in water These results demonstrate that the composition of the inventive is more effective than the use of only the phosphate compound in the clarification of the sugar syrup while reducing the total amount of the phosphate-containing compound employed. Other tests were performed on the sucrose test device. These results are present in Table II.

TABLE II Clarification of sugar syrup pH = 7 at 100 ° C Without S02 oxidant 2.0 ppm anionic polymer Test Calcium Pre-coagulant ABS Trans Color ICUMSA IV (ml / 1) (ppm) (420 nm) üi 1 5.5 0.6070 24 .7 5848 2 5.0 A (50) 0.5795 28.4 5583 3 5.0 B (50) 0.5130 31.5 4942 4 5.0 A (100) 0.5415 29.7 5217 5 4.3 B (100) 0.5135 31.3 4947 6 4.0 A (150) 0.5230 30.2 5039 7 3.8 B (150) 0.4530 35.5 4364 8 3.8 A (200) 0.5460 30.2 5260 9 3.5 B (200) 0.4040 39.6 3892 10 3.3 A (250) 0.4650 34.5 4480 11 3.3 B (250) 0.3840 41. 1 3699 A is sodium tripolyphosphate B is 20% dimethylamine-epichlorohydrin copolymer and 10% sodium tripolyphosphate, by weight, in water.

As seen in Table II, the composition of the inventive was more effective than the phosphate-containing compound in the production of a more clarified sugar solution from a range of 50 to 250 ppm active. Although this invention has been described with respect to the particular embodiments thereof, it is evident that numerous forms and modifications of this invention will be obvious to those skilled in the art. The annexed clauses and this invention should generally be considered to cover all of these obvious forms and modifications that are within the true spirit and scope of the present invention.

Claims (20)

1. One method for clarifying sugar syrup during sugar production is the addition to the syrup of an effective clarifying amount of a composition of a condensation polymer of a dihaloalkyl compound and a dialkylamine compound and a phosphate compound, the phosphate compound consisting of in at least one water-soluble compound that does not substantially lower the pH of the sugar syrup.

2. The method as claimed in claim 1, wherein the dialkylamine compound comprises at least one of the following: dimethylamine, diethylamine, dipropylamine, dibutylamine and dipentylamine.

3. The method as claimed in claim 1, wherein the dihaloalkyl is epichlorohydrin.

4. The method as claimed in claim 1, wherein the condensation polymer comes from the polymerization of epichlorohydrin and dimethylamine.

5. The method as claimed in claim 4, wherein the condensation polymer has a molecular weight in the range from about 8000 to about 14,000.

6. The method as claimed in claim 1, wherein the phosphate compound comprises at least one of the halogenated salts of phosphorus; tripolyphosphates; pyrophosphates; hexametaphosphate; and trisodium phosphates.

7. The method as claimed in claim 6, wherein the phosphate compound is sodium tripolyphosphate.

8. The method as claimed in claim 7, wherein the sodium tripolyphosphate is food grade.

9. The method as claimed in claim 1, wherein the sugar syrup is in a flotation or clarification system of a sugar manufacturing system.

10. The method as claimed in claim 1, wherein the sugar syrup is obtained from the sugar cane.

11. The method as claimed in claim 1, wherein the composition is added to the sugar syrup in an amount in the range of from about 50 parts to about 250 parts per parts of sugar syrup.

12. The method as claimed in claim 1, wherein the weight ratio of the condensation polymer to the phosphate compound is in the range of from about 2 to about 1.

13. A composition useful in the clarification of sugar syrup comprises a condensation polymer of a dihaloalkyl compound and a dialkylamine compound and a phosphate compound, the phosphate compound comprises at least one water-soluble compound that does not substantially lower the pH of the sugar syrup.

14. The composition as claimed in claim 13, wherein the dialkylamine compound comprises at least one of the following: dimethylamine, diethylamine, dipropylamine, dibutylamine and dipentylamine.

15. The composition as claimed in claim 14, wherein the dihaloalkyl is epichlorohydrin.

16. The composition as claimed in claim 13, wherein the condensation polymer comes from the polymerization of epichlorohydrin and dimethylamine.

17. The composition as claimed in claim 16, wherein the condensation polymer has a molecular weight in the range from about 8000 to about 14,000.

18. The composition as claimed in claim 13, wherein the phosphate compound comprises at least one of the phosphorus halogen salts; tripolyphosphates; pyrophosphates; hexametaphosphate; and trisodium phosphates.

19. The composition as claimed in claim 18, wherein the phosphate compound is sodium tripolyphosphate.

20. The composition as claimed in claim 19, wherein the sodium tripolyphosphate is food grade.