Sucrose crystallization mechanism of growth from aqueous solution

Vanhook, Andrew

doi:10.1016/0022-0248(69)90062-1

Cited by 12 publications

(4 citation statements)

References 9 publications

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“…As previously reported, the individual influence of d -fructose and d -glucose on sucrose crystallization is, mainly, focused on crystal morphology change. − The sucrose growth rates in the presence of these impurities are usually found in the literature not as an individual influence of these two monosaccharides but as a collective influence of invert sugar (an equimolar mixture of d -fructose and d -glucose). − Some exceptions can be found in the literature, as in Martins et al work. These authors studied the d -fructose influence on sucrose growth rate in industrial syrups and concluded that d -fructose has a strong impact on growth rate.…”

Section: Resultsmentioning

confidence: 97%

“…d -Fructose and d -glucose influence on sucrose crystallization are, mainly, focused on crystal morphology change. − Crystals grown in the presence of d -glucose are more elongated that the ones grown in the presence of d -fructose. In what concerns their influence on crystal growth rate, a decrease was observed when an equimolar mixture of d -fructose and d -glucose (invert sugar) was used. − Inorganic impurities such as CaCl 2 decrease the crystal growth rate and sucrose solubility, changing, by this way, the crystallization process. , As far as we know, information about the CaCl 2 influence on crystal habit is not available.…”

Section: Introductionmentioning

confidence: 99%

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Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Ferreira

Faria²,

Rocha

et al. 2011

Ind. Eng. Chem. Res.

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The morphological forms and habits of crystals and agglomeration are important properties on crystallization processes. Online techniques for realtime measurement of these properties are mandatory for a better comprehension of crystal growth phenomenon. The present paper presents and describes a new online method to determine the complexity level of a crystal or a population of crystals during a crystallization process. An image analysis technique is combined with discriminant factorial analysis leading to results that allow the computation of the complexity of crystals through the parameter agglomeration degree of crystals. With this methodology, it has been possible to distinguish online and automatically among three different classes of crystals according to their complexity. It further describes the application of such methodology on the study of CaCl 2 , D-fructose, and D-glucose influence on the crystallization of sucrose, namely, on crystal size, morphology, and complexity. The effect of supersaturation, growth rate, and impurity concentration on the type, amount, and complexity level of the agglomerates was determined at different temperatures. The combination of image analysis and kinetic results allowed to understand better the crystallization phenomena in the presence and absence of impurities. The image analysis results suggest the possible application of this tool for process control, optimizing, by this way, laboratory and industrial crystallizers. ' INTRODUCTIONThe impurities effect on crystal growth has been investigated over the years. A great deal of interest in this field is well attested in Sangwal's work. 1 Originating from raw materials and sometimes from production processes, the impurities affect not only the manufacturing process but also the crystallization kinetics. Some impurities act on the properties of the solutions while others act on the crystals surface, changing their morphology or habit. This morphology change is an important property that affects not only the downstream processing and handling but also the end-use functional properties. Crystal habit is closely associated with filterability, flowability, and compaction behavior among other properties. A sudden change in crystal habit may suggest the appearance of a new polymorph or the presence of trace impurities. Agglomeration may lead to profound changes in final product quality, as well as entrapment of unacceptable levels of occluded solvent, causing difficulties in washing and drying. 2 On the other hand, the impurity affinity for a specific crystal surface can be useful for crystal morphology changes. The tailormade additives have obtained great importance on crystal growth. They interact in specific ways with selected faces of crystalline materials, thereby inhibiting the growth of preselected faces, and not changing or changing slightly the growth of the other faces. Consequently, a specific crystal morphology is obtained. The additive molecules can lower the growth rate either by physically blocking the layers or by ...

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Ferreira

Faria²,

Rocha

et al. 2011

Ind. Eng. Chem. Res.

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“…Impurities like invert sugar [3][4][5][6][7][8], dextran [9][10][11], raffinose [8,12,13], salts and acids [8,[13][14][15], and colour [16][17][18][19][20][21] have been investigated in the last sixty years. However, little or no information is available in the literature on the mechanisms of impurity transfer during the crystallisation process.…”

Section: Introductionmentioning

confidence: 99%

The effect of crystal surface roughness on impurity adsorption

Ferreira

Faria²,

Rocha³

2009

Cryst. Res. Technol.

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The effect of crystal surface roughness on impurity adsorption was investigated in a fluidized bed crystallizer and in a batch crystallizer. The crystallisation of sucrose in pure and impure systems was the study subject. Calcium chloride was utilized as impurity in this work. The results show that the impurity adsorption is growth rate dependent and is strongly influenced by the crystal surface properties. Crystals with high surface roughness have lower impurity adsorption. Based on experimental evidences, a new theoretical model is proposed to quantify the surface roughness influence on the impurity adsorption, allowing, by operating at the more adequate supersaturation, to control the impurity transfer into crystals. The used impurity does not have a significant influence on the growth rates at the studied temperatures.

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“…A N ABUNDANCE OF LITERATURE EXISTS THAT DETAILS SUCROSE crystal growth under a variety of conditions, but most of the published work involves batch crystallization systems (Smythe 1967a;Smythe 1971;Van Hook 1969; Van Hook 1981). Although Hartel and Shastry (1991) reviewed the factors that influence sucrose crystallization, a lack of information about crystal growth in thin films still exists.…”

Section: Introductionmentioning

confidence: 99%

Drying and Crystallization of Sucrose Solutions in Thin Films at Elevated Temperatures

Howell

Hartel

2001

Journal of Food Science

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Thin sucrose films were dried over 30-min periods during which sucrose crystal growth rates were monitored by videomicroscopy. Drying parameters and sucrose solution properties were varied to determine their effect on initial sucrose crystal growth rates. Growth rates increased by a factor of 4.5 as temperature increased from 40 to 70 °C. Varying initial sucrose concentration (70 to 80%) and drying air velocity (2 to 5 m/s) produced no change in crystal growth rates. Increases in film thickness from 150 to 450 µm and the presence of moisture in the drying air reduced growth rates by 33% at 70 °C, but had no effect at 50 °C. The addition of invert sugar (up to 5%) reduced growth rates by a factor of 2 to 3.

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Sucrose crystallization mechanism of growth from aqueous solution

Cited by 12 publications

References 9 publications

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

The effect of crystal surface roughness on impurity adsorption

Drying and Crystallization of Sucrose Solutions in Thin Films at Elevated Temperatures

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