Detailed modeling and process design of an advanced continuous powder mixer

Toson, Peter; Siegmann, Eva; Trogrlic, M.; Kureck, Hermann; Khinast, Johannes G.; Jajčević, Dalibor; Doshi, Pankaj; Blackwood, Daniel O.; Bonnassieux, Alexandre; Daugherity, Patrick D.; Ende, Mary T. am

doi:10.1016/j.ijpharm.2018.09.032

Cited by 70 publications

(34 citation statements)

References 40 publications

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“…Vertical continuous mixing devices have broad RTDs that filter out mass fluctuations in the input stream. Typical mean residence times in a continuous mixing device are in the range of 100 s, and good mixing behaviour is indicated with number of CSTRs n close to 1 [29].…”

Section: Filtering Of Mass Flow Fluctuations In a Continuous Manufactmentioning

confidence: 98%

“…However, because of their different analytical forms, the only way to describe transitions between a bypassing condition and a non-ideal mixing condition, is to build reactor networks containing convective elements and CSTR cascades or utilising parallel CSTRs in reactor networks [13,25,28,32]. The TIS model has been generalised to a non-integer number of CSTRs in series [25], but it is also possible to utilise less than one CSTR to describe short-circuiting and bypassing effects [29]. The result is the generalised n-CSTR model.…”

Section: Generalised Cascade Of N Continuous Stirred Tank Reactors: Tmentioning

confidence: 99%

“…It makes sense to describe this scenario with n < 1. A real-world example is a vertical continuous mixing device described in Reference [29]. The construction is based on an ideal CSTR and for a range of operating conditions it behaves exactly like one (n = 1).…”

Section: Influence Of Shape Parameter Nmentioning

confidence: 99%

“…Figure 6a shows the response of the n-CSTR model to a rectangular inlet condition with a length of one MRT. While appearing artificial, this rectangular inlet condition is a good model for set point changes occurring in a continuous manufacturing process [9,10,29]. Even though the change in the inlet condition (e.g., mass flow, concentration) persists for one mean residence time, the peak at the outlet is damped significantly compared to the height of the rectangle.…”

Section: Filtering Of Mass Flow Fluctuations In a Continuous Manufactmentioning

confidence: 99%

“…This generalisation has been used as a stand-alone model and as a building block in reactor networks [13,24,[26][27][28]. Toson et al [29] used the model with a narrow parameter range 0.5 < n < 1.1 to fit the RTD of a continuous powder mixer and linked n to the quality of the mixing process.…”

Section: Introductionmentioning

confidence: 99%

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Explicit Residence Time Distribution of a Generalised Cascade of Continuous Stirred Tank Reactors for a Description of Short Recirculation Time (Bypassing)

2019

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The tanks-in-series model (TIS) is a popular model to describe the residence time distribution (RTD) of non-ideal continuously stirred tank reactors (CSTRs) with limited back-mixing. In this work, the TIS model was generalised to a cascade of n CSTRs with non-integer non-negative n. The resulting model describes non-ideal back-mixing with n > 1. However, the most interesting feature of the n-CSTR model is the ability to describe short recirculation times (bypassing) with n < 1 without the need of complex reactor networks. The n-CSTR model is the only model that connects the three fundamental RTDs occurring in reactor modelling by variation of a single shape parameter n: The unit impulse at n→0, the exponential RTD of an ideal CSTR at n = 1, and the delayed impulse of an ideal plug flow reactor at n→∞. The n-CSTR model can be used as a stand-alone model or as part of a reactor network. The bypassing material fraction for the regime n < 1 was analysed. Finally, a Fourier analysis of the n-CSTR was performed to predict the ability of a unit operation to filter out upstream fluctuations and to model the response to upstream set point changes.

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Section: Filtering Of Mass Flow Fluctuations In a Continuous Manufactmentioning

confidence: 98%

Section: Generalised Cascade Of N Continuous Stirred Tank Reactors: Tmentioning

confidence: 99%

Section: Influence Of Shape Parameter Nmentioning

confidence: 99%

Section: Filtering Of Mass Flow Fluctuations In a Continuous Manufactmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Explicit Residence Time Distribution of a Generalised Cascade of Continuous Stirred Tank Reactors for a Description of Short Recirculation Time (Bypassing)

2019

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A framework of hybrid model development with identification of plant‐model mismatch

Chen

Ierapetritou

2020

AIChE Journal

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Hybrid modeling has attracted increasing attention in order to take advantage of the additional data to improve process understanding. Current practice often adopts mechanistic models to predict process behaviors. These mechanistic models are based on physical understandings and experimental studies, but they sometimes lead to plant‐model mismatch (PMM) as they may be inaccurate to fully describe real processes. Black‐box models can serve as an alternative, but they often suffer from poor generalization and interpretability. To combine the two techniques, hybrid models are developed to make use of process data while maintaining a degree of physical understanding. In this work, we implement a framework of identification of PMM using partial correlation coefficient and mutual information, followed by introducing and comparing serial, parallel, and combined structures of hybrid models. The framework is applied and tested with a simulated reactor model and two pharmaceutical unit operation case studies.

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Numerical study of the mixing characteristics in an air swirling fluidized bed with monodisperse and multi‐sized particles

et al. 2023

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Powder mixers are used in many industries. In the present work, a new type of air swirling mixer was designed and optimized with eight horizontally arranged inlet pipes at the tangential inlet angle of 35°. The mixing of multi‐sized spherical particles (2.0, 3.0, 4.0, and 5.0 mm) was numerically investigated in the air swirling mixer by coupled computational fluid dynamics–discrete element method. The numerical results showed that multi‐sized particles achieved comparable mixing performance to monodisperse particles. The Lacey index for multi‐sized particles increased initially, and then reached a maximum value at 0.824. The upward velocity of the particles, , increased initially, and then decreased to zero along the bed height. The maximum value of occurred at a height of 40 mm. Particle radial velocity was larger near the wall than at the mixer tube centre area. The smallest particles aggregated in three layers. The collision number of the particles reached a maximum at bed height of 120 mm, which was consistent with the position of the maximum stress of the particles against the tube wall.

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Detailed modeling and process design of an advanced continuous powder mixer

Cited by 70 publications

References 40 publications

Explicit Residence Time Distribution of a Generalised Cascade of Continuous Stirred Tank Reactors for a Description of Short Recirculation Time (Bypassing)

Explicit Residence Time Distribution of a Generalised Cascade of Continuous Stirred Tank Reactors for a Description of Short Recirculation Time (Bypassing)

A framework of hybrid model development with identification of plant‐model mismatch

Numerical study of the mixing characteristics in an air swirling fluidized bed with monodisperse and multi‐sized particles

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