Measuring Size Distribution of Organic Crystals of Different Shapes Using Different Technologies

Patchigolla, Kumar; Wilkinson, Derek; Li, Mingzhong

doi:10.1002/ppsc.200601022

Cited by 5 publications

(12 citation statements)

References 15 publications

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“…Particle size distribution obtained with the laser diffraction method is based on averaged projected area equivalent diameters [16], and it is known that particle shape strongly affects the result of particle sizing [17].…”

Section: Discussionmentioning

confidence: 99%

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Effect of particle shape on hydrocyclone classification

et al. 2012

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Influence of particle shape on hydrocyclone classification was investigated. Classification tests using hydrocyclone and cyclosizer showed that coarse fractions of plate-like particles such as PTFE and glass flake used here were not necessarily recovered as underflow product, especially at relatively high inlet velocity. Settling velocity of the glass flake particles in centrifugal field was estimated using a centrifugal particle size analyzer, and it was revealed that differences in settling velocity between coarse and fine glass flake particles became smaller with increases in angular velocity. Moreover, settling test of glass plate in water or glycerin solution was conducted to know relationship between particle Reynolds number (Re) and settling velocity of the plate. At smaller Re condition, the glass plate settled straight and stably, and larger plate settled faster than smaller plate.However, oscillating motion of the plate occurred in the region of high Re, and settling velocities of the large plate became smaller than that of the small plate in such conditions. Drag coefficient (C) calculated based on the settling velocity of the glass plate is similar to that of glass spheres below Re of about 50, above which it became larger than that of glass sphere.Approximation formula of correlaton between Re and C suggests that the influence of the Re on C can be neglected in the region of high Re, and C increases with increases in the ratio of the particle diameter to thicknessThe decrease of the difference in settling velocity recognized in the centrifugal settling test and the effect of the particle shape (D/T) on C at high Re region are considered to be able to affect the hydrocyclone classification.The misplacement of coarse plate-like particles in the hydrocyclone and cyclosizer tests could be ascribed to the particle shape effects.

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Section: Discussionmentioning

confidence: 99%

“…Classification tests using hydrocyclones and a cyclosizer, centrifugal settling tests, and gravitational settling tests were conducted to investigate 16 the influence of particle shape on hydrocyclone classification.…”

Section: Discussionmentioning

confidence: 99%

Effect of particle shape on hydrocyclone classification

et al. 2012

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“…Another interesting study in this paper was conversion of median values between different techniques like UAS, LDS and image analysis (MIA and Camsizer). More details about UAS, and LDS measurement techniques and the equations used for error calculation were presented in another paper [18]. The differences between measurements by MIA, Camsizer, UAS and LDS are summarised in Table 4.…”

Section: Resultsmentioning

confidence: 99%

Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis

Patchigolla

Wilkinson

2009

Part & Part Syst Charact

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A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi‐automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L‐glutamic acid which crystallises into α (prismatic) or β (needle) form and the non‐polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies. In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non‐spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques.

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“…Ultrasonic spectroscopy enables the determination of particle size distributions and concentrations in highly concentrated dispersion processes (up to 70% by volume) . The measurement method is utilized, among other things, for the process analysis and control of colloidal suspensions in milling, crystallization, and polymerization applications . A comprehensive overview of the state‐of‐the‐art and its application is given by Babick .…”

Section: Introductionmentioning

confidence: 99%

“…In the literature, a wide variety of applications are reported in which FBRM systems have been successfully applied. For example, FBRM systems were used to study crystallization and nucleation processes and to design and control flocculation processes . With regard to the measurement capability of the FBRM in emulsions, investigations have been carried out by several authors .…”

Section: Introductionmentioning

confidence: 99%

Investigations on the Capability of the Statistical Extinction Method for the Determination of Mean Particle Sizes in Concentrated Particle Systems

Schwarz

Ripperger

Antonyuk

2018

Part & Part Syst Charact

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Due to the fast growing number of processes involving particulate systems, simple and robust measurement techniques which enable an inline monitoring of the particle size and their concentration are urgently required, since this ensures control but also process optimization. In this work, an inline measurement technique based on the statistical extinction method is developed that provides a process monitoring for a wide range of particulate processes, such as dispersion processes and spray processes. The method allows the determination of the mean size and concentration for particle systems with the size larger than 1 µm. For this purpose, a light beam illuminates the particle system, whereby the fluctuating light intensity due to the particle movement through the light beam is detected. The statistical fluctuation of the signal can be related to a mean particle size and a particle concentration. Since concentrated particle systems cause effects that additionally influence the signal, such as multiple scattering, approaches are needed to reduce or eliminate these effects. In this work, an approach using a spatial frequency filter is applied. The experimental investigations reveal that the effects can be significantly reduced with the spatial frequency filter.

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Measuring Size Distribution of Organic Crystals of Different Shapes Using Different Technologies

Abstract: paper, the same phenomenon was observed with evolving polymorphs of L-glutamic acid crystals (a and b form), oxalic acid, sucrose and monosodium glutamate.

Cited by 5 publications

References 15 publications

Effect of particle shape on hydrocyclone classification

Effect of particle shape on hydrocyclone classification

Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis

Investigations on the Capability of the Statistical Extinction Method for the Determination of Mean Particle Sizes in Concentrated Particle Systems

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