Crystallization Kinetics of Alpha‐Lactose Monohydrate in a Continuous Cooling Crystallizer

Abstract

The crystallization of alpha-lactose monohydrate in a continuous cooling crystallizer was investigated at various temperatures and supersaturations. The population balance model was used to analyze the product crystal size distribution as determined by the Coulter MultiSizer for each condition studied. Nucleation and growth values were thereby determined for each temperature and supersaturation. Kinetic models were then developed for both nucleation and growth to demonstrate the effects of the operating parameters. The results showed that the nucleation process had a temperature dependence with an activation energy of 17.0 kcal/mole and that nucleation increased with the 1.9 power of supersaturation and the 1.0 power of the suspension density (mass of crystals). The growth process was found to have a temperature dependence with an activation cncrgy of 22.1 kcahmole and to be a second order function of the supersaturation.

Effect of galacto-oligosaccharide concentration on the kinetics of lactose crystallisation

“…2. When the growth rates for the various supersaturation levels and with no GOS added were compared with those available in the literature, they were found to be very comparable within the experimental scatter present in the literature data (Griffiths, Paramo, & Merson, 1982;Jelen & Coulter, 1973;McLeod, 2007;Shi, Liang, & Hartel, 1990). Evident is an overall exponential increase in crystal growth rate with increasing supersaturation.…”

“…F GOS_G ¼ e ðÀ0:332$%GOSÞ (1) G R ¼ F GOS_G $0:026373$ðC a À C as Þ 1:105 (2) F GOS_G is the factor expressing the growth retarding effect of GOS, %GOS is the weight percentage of GOS in solution, C a is the alactose concentration in g a-lactose per 100 g water, C as is the alactose concentration in g a-lactose 100 g water À1 at saturation and G R is the overall growth rate of the lactose crystals in mm min À1 . Shi, Hartel, and Liang (1989) and Shi et al (1990). The 2% results shows the drop in growth rate is neatly fitted with the growth retarding factor fitted.…”

Ultrasound Assisted Engineering of Lactose Crystals

“…This is due to large metastable zone width, which require very high supersaturation for induction to occur (6). Attempts for rapid crystallization of lactose include seeding crystallization (7,8), anti-solvent precipitation using ethanol (9,10), methanol (11), DMSO (12), acetone (13) and sonocrystallization (14). Nature and time of seed addition affects the crystal habit limiting the applicability and reproducibility of process (15,16).…”

Kinetics of lactose crystallization and crystal size as monitored by refractometry and laser light scattering: effect of proteins

“…Additionally, the shape and size of lactose in the solid phase was examined by optical microscopy [4], polarized light microscopy and image analysis [1], scanning electron microscopy [9], electrozone particle counting [11] and laser light scattering at the final stage [9]. Several strategies were also performed to evaluate growth parameters of lactose crystals: single crystal growth at constant supersaturation [1,2] or the MSMPR (mixed suspension mixed product removal) approach [11]. In the present work, we applied two methods to follow in real time and simultaneously the course of the whole batch crystallization over time, both in the liquid phase, by measuring changes in lactose dissolved concentration using refractometry, and in the solid phase, analyzing evolution of CSD (crystal size distribution) by laser light scattering.…”

“…Among the most recent research, lactose concentration in the liquid phase was measured by the enzymatic method [12], refractometry [4,7] or indirectly by weighing crystals formed over time [2,9]. Additionally, the shape and size of lactose in the solid phase was examined by optical microscopy [4], polarized light microscopy and image analysis [1], scanning electron microscopy [9], electrozone particle counting [11] and laser light scattering at the final stage [9]. Several strategies were also performed to evaluate growth parameters of lactose crystals: single crystal growth at constant supersaturation [1,2] or the MSMPR (mixed suspension mixed product removal) approach [11].…”