Particle‐shape monitoring and control in crystallization processes

Patience, Daniel B.; Rawlings, James B.

doi:10.1002/aic.690470922

Cited by 115 publications

(91 citation statements)

References 10 publications

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“…There is some work regarding the methods to modify the crystal size by controlling the supersaturation level during crystal growth [18,155] or by using impurities to manipulate the shape of crystals for sodium chlorate, which also represents an important direction since the use of impurity is considered in industry as an effective handle for size control. Several studies were carried out to develop some robust closed-loop control strategies (for example [1,64,139,[156][157][158][159][160]) with the help of the advanced in-situ sensors developed in last decade.…”

Section: Optimisation and Control Of Crystal Size Distribution (Csd)mentioning

confidence: 99%

“…An generic model control strategy for on-line dynamic optimization and batch-to-batch optimization has been studied for improving the product quality of a seeded batch cooling crystallization [189]. Patience and Rawlings [18] investigated the use of impurities to manipulate the shape of crystals for sodium chlorate, which also represents an important direction since the use of impurity is considered in industry as a very effective handle for shape control. A model predictive controller with PB modelling of protein crystallisation was used to produce crystals with a desired shape distribution [40].…”

Section: Crystal Shape Optimisation and Control Using Mpbmsmentioning

confidence: 99%

“…Patience and Rawlings [18] investigated the use of the PVM for measuring the shape and size information of sodium chlorate crystals with support from Pfizer. Larsen et al [29,39] developed new algorithms including model-based object recognition for image analysis, and also highlighted the necessity of advances in image analysis to improve image segmentation when particle overlap is significant.…”

Section: Two-dimensional Imaging Approachesmentioning

confidence: 99%

“…The influence of added impurities was mainly studied for single crystals to quantify the kinetic effect individually rather than for the population of crystals in the crystalliser. Patience and Rawlings [18] designed a closed-loop feedback control system for shape control in which the shape was monitored by an imaging system, and the control was achieved by manipulating the flow rate of a habit modifier stream. Poornachary et al [193] studied the effects of added amino acids on the habit modification in glycine crystals obtained via solution crystallisation.…”

Section: Manipulated Variables For Crystal Shape Optimisation and Conmentioning

confidence: 99%

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Measurement, modelling, and closed-loop control of crystal shape distribution: Literature review and future perspectives

2016

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Crystal morphology is known to be of great importance to the end-use properties of the crystal product and affect the down-stream processing such as in filtration and drying, but was previously regarded as too challenging to achieve automatic closed-loop control. As a consequence, previous work has focused on control the crystal size distribution (CSD) where the size of a crystal is often defined as the diameter of a sphere that has the same volume of the crystal. This paper reviews very promising new advances made in recent years in morphological population balance models for modelling and simulation of crystal shape distribution (CShD), measurement and estimation of crystal facet growth kinetics, as well as in 2D and 3D imaging for on-line characterisation of crystal morphology and CShD. A framework is presented integrating various components in order to achieve the ultimate objective of model-based closed-loop control of CShD. The knowledge gaps and challenges that require further research are also identified.

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Section: Optimisation and Control Of Crystal Size Distribution (Csd)mentioning

confidence: 99%

Section: Crystal Shape Optimisation and Control Using Mpbmsmentioning

confidence: 99%

Section: Two-dimensional Imaging Approachesmentioning

confidence: 99%

Section: Manipulated Variables For Crystal Shape Optimisation and Conmentioning

confidence: 99%

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Measurement, modelling, and closed-loop control of crystal shape distribution: Literature review and future perspectives

2016

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“…On measurement, on-line microscopic imaging and image analysis for real-time characterisation of the shape and CShD of crystals in a crystalliser has attracted much attention in recent years (Barrett and Glennon, 2002;Calderon de Anda et al, 2005a;Calderon De Anda et al, 2005b;Huo et al, 2016;Larsen and Rawlings, 2009;Larsen et al, 2006;Patience and Rawlings, 2001;Wang et al, 2007;Zhang et al, 2015;Zhao et al, 2013;Zhou et al, 2011;Zhou et al, 2009). There are also readily available products on the market such as Mettler Toledo's PVM MessTechnik's PIA , PharmaVision (Qingdao) Ltd's 2D…”

Section: Introductionmentioning

confidence: 99%

Stereo imaging camera model for 3D shape reconstruction of complex crystals and estimation of facet growth kinetics

Zhang

Cai

Liu

et al. 2017

Chemical Engineering Science

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The principle that the 3D shape of crystals that grow from a solution can be characterised in real-time using stereo imaging has been demonstrated previously. It uses the 2D images of a crystal that are obtained from two or more cameras arranged in defined angles as well as a mathematical reconstruction algorithm. Here attention is given to the development of a new and more robust 3D shape reconstruction method for complicated crystal structures. The proposed stereo imaging camera model for 3D crystal shape reconstruction firstly rotates a digitised crystal in the three-dimensional space and varies the size dimensions in all face directions. At each size and orientation, 2D projections of the crystal, according to the angles between the 2D cameras, are recorded. The contour information of the 2D images is processed to calculate Fourier descriptors and radius-based signature that are stored in a database. When the stereo imaging instrument mounted on a crystalliser captures 2D images, the images are segmented to obtain the contour information and processed to obtain Fourier descriptors and radius-based information. The calculated Fourier descriptors and radius-based signature are used to find the best matching in the database. The corresponding 3D crystal shape is thus found. Potash alum crystals that each has 26 habit faces were used as a case study. The result shows that the new approach for 3D shape reconstruction is more accurate and significantly robust than previous methods. In addition, the growth rates of {111}, {110} and {100} faces were correlated with relative supersaturation to derive models of facet growth kinetics.

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