Cane Sugar Refining - Purolite

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Cane Sugar Refining with Ion Exchange Resins Amorfo Sugar An alternative product to crystalline or liquid sugar is the microcrystalline Amorfo Sugar which is produced primarily in Brazil and to a much lesser degree in Mexico. Amorfo is produced by rapid crystallization (45 seconds) under intense agitation in an open pan. This process results in nearly 100% yield and has the advantage of low capital cost, low steam and power consumption, no molasses and high production ratio per equipment. Since there is no separation from the mother liquor, it is necessary to start with low color sugar (50 IU) with minimum impurities and reducing sugars less than 0.2%. Ion exchange decolorization and demineralization is used to achieve the level of purity required. 6 % Decolorization 50% Affination 40% Carbonatation or Phosphatation 75% Decolorization Sugar for Remelt CANE SUGAR REFINING PROCESS Raw Sugar Affinated Sugar Melt Liquor 800 IU Clarified and Filtered Syrup Decolorized Syrup 1 st Pan Syrup 2 nd , 3 rd , 4 th , 5 th Boiling Molasses Decolorization/ Demineralization Inversion/ Demineralization Color 1500 IU 750 IU 480 IU 120 IU Crystalline White Sugar 10-25 IU Liquid Sucrose 5-20 IU 0.005% ash Liquid Invert
Decolorization with Ion Exchange Resins 7 Cane Sugar Refining with Ion Exchange Resins Ion exchange resins used in the sugar industry as decolorizers are of the strong-base anionic type, with quaternary amine functional groups. They are operated in the chloride form. The resin matrix is usually composed of one of two types of polymeric material: polystyrenic with divinylbenzene crosslinks, resulting in a hydrophobic matrix, or a polyacrylic with divinylbenzene crosslinks which results in a more hydrophilic matrix. Some refineries, for the major decolorization, use only one resin type, acrylic or styrenic. Others employ an acrylic resin followed by a styrenic resin for polishing. The acrylic resin removes large molecular weight colored compounds which tend to foul the styrenic resin, providing good protection to the polishing resin. Acrylic resins have a slightly lower selectivity for sugar colorants but, unlike polystyrenic resins, they can be completely regenerated with sodium chloride solutions. This can be explained by the more hydrophilic character of the acrylic resin matrix. Even dark regenerant effluents from styrenic resins can be used to regenerate acrylic resins. The use of acrylic resin is justified when the color load is high and a low level of decolorization may be expected. Also, the use of a two pass system gives a more constant level of decolorization than when only one resin bed is used. Styrenic resins are more prone to fouling by organic compounds than acrylic resins and need occasional acid regeneration. Also, their decolorization capacity is higher than that of acrylic resins, but the color is not so efficiently removed during regeneration and capacity can drop rapidly if overloaded. Styrenic resins have a higher decolorization power because of their ability to fix colorants both through ionic bonds to the ionic active groups and through hydrophobic interactions with the resin matrix. Hydrophobic interactions increase with salt concentration, explaining the difficulty of using salt solutions to remove colorants fixed to the resin matrix. Polystyrenic resins with an aromatic matrix should have a higher affinity for unsaturated colorants than acrylic resins. Styrenic resin types are favored when the inlet color is on the low end (i.e. up to 800 ICUMSA) and acrylic types when it is higher. Numerous plants today operate with a combination of both types, which is advisable when the inlet feed color fluctuates during the season.
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Cane Sugar Refining - Purolite

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