Pietro Binel

Last Name

Binel

First Name

Pietro

ORCID

0000-0001-8263-7643

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Publications 1 - 7 of 7

On the Use of Hydrocyclones for Enhanced Fines Dissolution in Batch Cooling Crystallization
Binel, Pietro (2022)
Crystallization is a purification technique applied in a number of industrial fields. In particular, cooling crystallization is widespread to recover a product in solid form from solution. This thesis focuses on the engineering of crystal size and shape, which is relevant to ensuring that the crystalline powder meets the quality standards for easy downstream processing. More specifically, procedures for the removal of fine crystals in suspension and the effect on the product quality are investigated. Partial dissolution, during which the suspension is heated until a chosen mass fraction of crystals has dissolved, is the state-of-the-art procedure for fines removal. The fines are the smallest crystals in the population, having a size below a few tens of micrometers. Here, we propose and analyze an alternate procedure for fines removal, referred to as the selective dissolution process. In this procedure, a hydrocyclone is used to separate the fines in suspension from the rest of the crystal population, so that dissolution can be applied selectively to them. Hydrocyclones are simple, low-maintenance, and cheap solid-liquid separation devices, applied in many fields of chemical engineering. Taking advantage of centrifugal sedimentation, they are capable of classifying particles in suspension based on their size. The selective dissolution process is first studied with a modeling approach. Crystallization and hydrocyclone separation are modeled in detail using a population balance equation framework and a model from the literature, respectively. The model is used to run simulations to understand the effect of the operating parameters on the process performance. At the same time, the performance of the selective dissolution process is compared to that of partial dissolution, i.e., the state of the art. Next, the modeled trends are verified through experiments. The experimental campaign confirms the modeled trends and shows that the selective dissolution process offers better performance, that is, more fines can be removed from the suspension while less solid mass has to be dissolved. The model employed in the modeling study for the simulation of the hydrocyclone, proposed by Braun, is fitted to the experimental data and its robustness is verified using a cross-validation approach. The modified model is observed to accurately predict the separation curves of hydrocyclones of different sizes and operated under different conditions. Proven the effectiveness of the selective dissolution process, it is implemented into a 3-stage cyclic crystallization process, which enables size and shape manipulation. The 3-stage process consists in the sequential application of crystallization, wet milling, and partial dissolution; the three stages are repeated a given number of times until the target yield is met. The performance of the process in terms of final particle size and shape distribution, flowability, and filterability of the powder is evaluated. In particular, the performance indicators are compared for the process run with partial dissolution or with selective dissolution. It is observed that improved properties are obtained when applying selective dissolution, thus demonstrating the usefulness of the concept as well as its feasibility at a laboratory scale with suspensions of different densities and viscosities. At last, a study is conducted on the DISCO, the device used in all experimental activities to measure particle size and shape. Its capability of measuring the three characteristic dimensions of cuboidal particles online and in-flow is demonstrated through a novel approach, in which bespoke analytical standards are fabricated by photolithography. This study, by proving the accuracy of the device, enables its reliable use to investigate the role of particle shape in the hydrocyclone separation, as well as the particle size and shape manipulation capability of the 3-stage process with cuboidal-like particles.
A Selective Dissolution Process Featuring a Classification Device for the Removal of Fines in Crystallization
Binel, Pietro; Mazzotti, Marco (2021)
Industrial & Engineering Chemistry Research
The presence of fine crystals is a common condition that may hinder the downstream processing of a powder obtained through a crystallization process. This study investigates through simulations a process featuring a hydrocyclone for their removal. Hydrocyclones, solid–liquid separation devices widely applied in several fields of chemical engineering, enable the classification of suspended solids based on their size. The classification step allows for a selective dissolution of the fine crystals, thus leading to a more efficient process when compared to a simpler temperature cycle, where partial dissolution of larger crystals is deliberately though reluctantly accepted. A pathway for the selection of a suitable hydrocyclone design is outlined, and a novel graphical tool useful to describe the performance of the device for the fines separation task is presented. The selection of the operating variables and their operating window is discussed, and their effect on the overall process is elucidated. The design space and the performance of the selective fines removal process is investigated by coupling for the first time the detailed modeling of fines dissolution by heating and crystallization by cooling, both based on population balance equations, and the hydrocyclone behavior, for which an established model due to Braun is used. Simulation runs are presented for different scenarios and allow assessing the process performance in terms of reductions of fines, processing time, and energy demand, thus providing a valuable insight into its applicability.
Efficient assessment of combined crystallization, milling, and dissolution cycles for crystal size and shape manipulation
Salvatori, Fabio; Binel, Pietro; Mazzotti, Marco (2019)
Chemical Engineering Science: X
A 3-stage process, consisting of a combination of crystallization, milling, and dissolution stages for the selective manipulation of the size and shape of crystals, is investigated to characterize its performance when applied to different substances. To this aim, simulations are used to screen, via a parametric analysis, the effect of different compound properties and operating conditions on the size and shape of the final products. Through this analysis, characteristic trends of general validity are identified, thus allowing to define families of compounds with similar behavior and features. Based on these results, a set consisting of a small number of experiments is devised to fully characterize the outcome of the 3-stage process for a specific substance. An experimental validation is carried out by performing this set of experiments with two compounds, namely l-Glutamic acid and d-Mannitol, thus assessing the suitability of this method for a comprehensive characterization of the process and its outcome. The information collected at the end of the different stages throughout all the experiments is further exploited to estimate the growth rates of d-Mannitol, in order to validate the observations made through simulations regarding the effect of growth kinetics on the process outcome. Finally, the model, fitted to the experimental evidence collected, has been used to further investigate and characterize the design space.
Selective Dissolution Process Featuring a Classification Device for the Removal of Fines in Crystallization: Experiments
Binel, Pietro; Mazzotti, Marco (2021)
Industrial & Engineering Chemistry Research
With the aim of removing fine particles from a suspension obtained by crystallization, a selective dissolution process featuring a hydrocyclone is compared against a well-established partial dissolution process with a dedicated experimental campaign, which complements an earlier theoretical study. For this purpose, 3D printed hydrocyclones, solid- liquid separation devices, are studied in detail and successfully operated under conditions viable at the laboratory scale. A model due to Braun is fitted to the experimental results and validated using a cross validation strategy, thus providing a valuable tool for process simulation. The experimental campaign is designed to comparatively assess the efficacy and efficiency of the two processes under analysis as a function of their respective operating conditions, finally demonstrating the superior performance of the selective dissolution process. In particular, it is shown that while in a standard partial dissolution process 20-40% of the suspended mass has to be dissolved to remove a reasonable amount of fines, the proposed process reaches the same goal by dissolving as little as 3-10%.
Improving the Performance of a 3-Stage Cyclic Crystallization Process Using a Hydrocyclone
Binel, Pietro; Mazzotti, Marco (2022)
Industrial & Engineering Chemistry Research
A rliqsolution process featuring a hydrocyclone for the selective removal of fine crystals, i.e., an operation analyzed through modeling and experiments in earlier studies, is implemented into a 3-stage cyclic crystallization process, which consists of repeated application of crystal growth, wet milling, and dissolution. For the selection of a hydrocyclone and of its operating conditions, experiments demonstrate that a mathematical model provides accurate estimates of the classification curve for different compounds and physical properties of the suspension, thus facilitating the process design. Two campaigns are conducted with two compounds, namely, gamma D-mannitol and beta L-glutamic acid, where the selective dissolution strategy is compared to standard partial dissolution in terms of the attributes of the final product powder obtained from the 3-stage process. Crystal size, crystal shape, flowability, and filterability are measured, and it is shown that they are greatly influenced by the dissolution stages. Most remarkably, in the case of gamma D-mannitol, the experimental evidence shows that selective dissolution enables the removal of a greater amount of fines for the same mass of crystals being dissolved, thus improving the productivity of the process, as well as the measured flow and filtration performance.
Online 3D Characterization of Micrometer-Sized Cuboidal Particles in Suspension
Binel, Pietro; Jain, Ankit; Jaeggi, Anna; et al. (2023)
Small Methods
Characterization of particle size and shape is central to the study of particulate matter in its broadest sense. Whilst 1D characterization defines the state of the art, the development of 2D and 3D characterization methods has attracted increasing attention, due to a common need to measure particle shape alongside size. Herein, ensembles of micrometer-sized cuboidal particles are studied, for which reliable sizing techniques are currently missing. Such particles must be characterized using three orthogonal dimensions to completely describe their size and shape. To this end, the utility of an online and in-flow multiprojection imaging tool coupled with machine learning is experimentally assessed. Central to this activity, a methodology is outlined to produce micrometer-sized, non-spherical analytical standards. Such analytical standards are fabricated using photolithography, and consist of monodisperse micro-cuboidal particles of user-defined size and shape. The aforementioned activities are addressed through an experimental framework that fabricates analytical standards and subsequently uses them to validate the performance of our multiprojection imaging tool. Significantly, it is shown that the same set of data collected for particle sizing can also be used to estimate particle orientation in flow, thus defining a rapid and robust protocol to investigate the behavior of dilute particle-laden flows.
Ziegler-Natta catalyst sonofragmentation for controlling size and size distribution of the produced polymer particles
Klaue, Antoine; Kruck, Matthias; Binel, Pietro; et al. (2019)
AIChE Journal

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Pietro Binel

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