Journal articles: 'Continuous Crystallization System'

1

TAHARA, Kohei. "Spherical Crystallization for Pharmaceutical Continuous Manufacturing System." Hosokawa Powder Technology Foundation ANNUAL REPORT 25 (2017): 75–78. http://dx.doi.org/10.14356/hptf.15111.

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Loren, Bradley P., Michael Wleklinski, Andy Koswara, Kathryn Yammine, Yanyang Hu, Zoltan K. Nagy, David H. Thompson, and R. Graham Cooks. "Mass spectrometric directed system for the continuous-flow synthesis and purification of diphenhydramine." Chemical Science 8, no. 6 (2017): 4363–70. http://dx.doi.org/10.1039/c7sc00905d.

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Yang, Xiaochuan, David Acevedo, Adil Mohammad, Naresh Pavurala, Huiquan Wu, Alex L. Brayton, Ryan A. Shaw, et al. "Risk Considerations on Developing a Continuous Crystallization System for Carbamazepine." Organic Process Research & Development 21, no. 7 (July 8, 2017): 1021–33. http://dx.doi.org/10.1021/acs.oprd.7b00130.

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Tahara, Kohei, Marcus O’Mahony, and Allan S. Myerson. "Continuous Spherical Crystallization of Albuterol Sulfate with Solvent Recycle System." Crystal Growth & Design 15, no. 10 (September 17, 2015): 5149–56. http://dx.doi.org/10.1021/acs.cgd.5b01159.

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Chan, V. A., and H. M. Ang. "A laboratory continuous crystallization system for aluminium hydroxide precipitation studies." Journal of Crystal Growth 166, no. 1-4 (September 1996): 1009–14. http://dx.doi.org/10.1016/0022-0248(96)00061-9.

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Žáček, Stanislav, and Jaroslav Nývlt. "Continuous Precipitation of Lead Iodide." Collection of Czechoslovak Chemical Communications 59, no. 7 (1994): 1503–10. http://dx.doi.org/10.1135/cccc19941503.

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Lead iodide was precipitated from aqueous solutions of 0.015 - 0.1 M Pb(NO3)2 and 0.03 - 0.2 M KI in the equimolar ratio using a laboratory model of a stirred continuous crystallizer at 22 °C. After reaching the steady state, the PbI2 crystal size distribution was measured sedimentometrically and the crystallization kinetics was evaluated based on the mean particle size. Both the linear crystal growth rate and the nucleation rate depend on the specific output of the crystallizer. The system crystallization constant either points to a significant effect of secondary nucleation by the mechanism of contact of the crystals with the stirrer blade, or depends on the concentrations of the components added due to the micromixing mechanism.

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Mack, Corin, Johannes Hoffmann, Jan Sefcik, and Joop H. ter Horst. "Phase Diagram Determination and Process Development for Continuous Antisolvent Crystallizations." Crystals 12, no. 8 (August 6, 2022): 1102. http://dx.doi.org/10.3390/cryst12081102.

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The development of an antisolvent crystallization process requires the construction of an accurate phase diagram for this ternary system of compound, solvent and antisolvent, preferably as a function of temperature. This study gives an efficient methodology to systematically determine such antisolvent phase diagrams, exemplified with four model compounds: Sodium bromate, DL-Asparagine Monohydrate, Mefenamic acid and Lovastatin. Using clear point temperature measurements, single solvent and mixed solvent-antisolvent solubilities are obtained, showing strongly non-linear solubility dependencies as well as more complex solubility behaviour as a function of antisolvent fraction. A semi-empirical model equation is used to describe the phase diagram of the antisolvent crystallization system as a function of both temperature and antisolvent fraction. The phase diagram model then allows for the identification of condition ranges for optimal productivity, yield, and suspension density in continuous antisolvent crystallization processes.

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Nordquist, Kyle, Tiffany Kinnibrugh, Kevin Scaab, and Andrew Bond. "Use of enhanced nucleation surfaces in a continuous flow crystallization system." Acta Crystallographica Section A Foundations and Advances 75, a1 (July 20, 2019): a55. http://dx.doi.org/10.1107/s0108767319099446.

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Cui, Yuqing, Marcus O’Mahony, Juan J. Jaramillo, Torsten Stelzer, and Allan S. Myerson. "Custom-Built Miniature Continuous Crystallization System with Pressure-Driven Suspension Transfer." Organic Process Research & Development 20, no. 7 (June 27, 2016): 1276–82. http://dx.doi.org/10.1021/acs.oprd.6b00113.

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Lai, Tsai-Ta C., Steven Ferguson, Laura Palmer, Bernhardt L. Trout, and Allan S. Myerson. "Continuous Crystallization and Polymorph Dynamics in the l-Glutamic Acid System." Organic Process Research & Development 18, no. 11 (July 16, 2014): 1382–90. http://dx.doi.org/10.1021/op500171n.

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Hu, Chuntian, Joshua E. Finkelstein, Wei Wu, Khrystyna Shvedova, Christopher J. Testa, Stephen C. Born, Bayan Takizawa, et al. "Development of an automated multi-stage continuous reactive crystallization system with in-line PATs for high viscosity process." Reaction Chemistry & Engineering 3, no. 5 (2018): 658–67. http://dx.doi.org/10.1039/c8re00078f.

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Höving, Stefan, Phil Bolien, Paul Siebers, and Norbert Kockmann. "Simplified Approach to Characterize the Cooling Crystallization in a Modular Mini-Plant." Crystals 13, no. 1 (January 14, 2023): 147. http://dx.doi.org/10.3390/cryst13010147.

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The characterization of new process equipment often includes tedious experiments, particularly for (cooling) crystallization. This can be cost-intensive and time-consuming when the actual equipment has to be continuously operated to gain new insights. For multi-purpose plants that frequently change the process substance system, this can be especially laborious. In order to accelerate the generation of characterization data for the quasi-continuous filter belt crystallizer (QCFBC), a Peltier-element-driven, simplified experimental benchtop setup is validated in this work using a sucrose/water model substance system. It was shown that the operation conditions during the cooling crystallization on the continuously operated plant can be appropriately emulated; therefore, an actual operation of the entire mini-plant for characterization experiments is no longer necessary.

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Hülsewede, Dennis, Erik Temmel, Peter Kumm, and Jan von Langermann. "Concept Study for an Integrated Reactor-Crystallizer Process for the Continuous Biocatalytic Synthesis of (S)-1-(3-Methoxyphenyl)ethylamine." Crystals 10, no. 5 (April 27, 2020): 345. http://dx.doi.org/10.3390/cryst10050345.

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An integrated biocatalysis-crystallization concept was developed for the continuous amine transaminase-catalyzed synthesis of (S)-1-(3-methoxyphenyl)ethylamine, which is a valuable intermediate for the synthesis of rivastigmine, a highly potent drug for the treatment of early stage Alzheimer’s disease. The three-part vessel system developed for this purpose consists of a membrane reactor for the continuous synthesis of the product amine, a saturator vessel for the continuous supply of the amine donor isopropylammonium and the precipitating reagent 3,3-diphenylpropionate and a crystallizer in which the product amine can continuously precipitate as (S)-1-(3-methoxyphenyl)ethylammonium-3,3-diphenylpropionate.

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Kufner, Anne Cathrine, Adrian Krummnow, Andreas Danzer, and Kerstin Wohlgemuth. "Strategy for Fast Decision on Material System Suitability for Continuous Crystallization Inside a Slug Flow Crystallizer." Micromachines 13, no. 10 (October 21, 2022): 1795. http://dx.doi.org/10.3390/mi13101795.

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There is an increasing focus on two-phase flow in micro- or mini-structured apparatuses for various manufacturing and measurement instrumentation applications, including the field of crystallization as a separation technique. The slug flow pattern offers salient features for producing high-quality products, since narrow residence time distribution of liquid and solid phases, intensified mixing and heat exchange, and an enhanced particle suspension are achieved despite laminar flow conditions. Due to its unique features, the slug flow crystallizer (SFC) represents a promising concept for small-scale continuous crystallization achieving high-quality active pharmaceutical ingredients (API). Therefore, a time-efficient strategy is presented in this study to enable crystallization of a desired solid product in the SFC as quickly as possible and without much experimental effort. This strategy includes pre-selection of the solvent/solvent mixture using heuristics, verifying the slug flow stability in the apparatus by considering the static contact angle and dynamic flow behavior, and modeling the temperature-dependent solubility in the supposed material system using perturbed-chain statistical associating fluid theory (PC-SAFT). This strategy was successfully verified for the amino acids l-alanine and l-arginine and the API paracetamol for binary and ternary systems and, thus, represents a general approach for using different material systems in the SFC.

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Powell, Keddon A., Giulia Bartolini, Kate E. Wittering, Ali N. Saleemi, Chick C. Wilson, Chris D. Rielly, and Zoltan K. Nagy. "Toward Continuous Crystallization of Urea-Barbituric Acid: A Polymorphic Co-Crystal System." Crystal Growth & Design 15, no. 10 (September 14, 2015): 4821–36. http://dx.doi.org/10.1021/acs.cgd.5b00599.

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Müller, Ilka. "Guidelines for the successful generation of protein–ligand complex crystals." Acta Crystallographica Section D Structural Biology 73, no. 2 (February 1, 2017): 79–92. http://dx.doi.org/10.1107/s2059798316020271.

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With continuous technical improvements at synchrotron facilities, data-collection rates have increased dramatically. This makes it possible to collect diffraction data for hundreds of protein–ligand complexes within a day, provided that a suitable crystal system is at hand. However, developing a suitable crystal system can prove challenging, exceeding the timescale of data collection by several orders of magnitude. Firstly, a useful crystallization construct of the protein of interest needs to be chosen and its expression and purification optimized, before screening for suitable crystallization and soaking conditions can start. This article reviews recent publications analysing large data sets of crystallization trials, with the aim of identifying factors that do or do not make agoodcrystallization construct, and gives guidance in the design of an expression construct. It provides an overview of common protein-expression systems, addresses how ligand binding can be both help and hindrance for protein purification, and describes ligand co-crystallization and soaking, with an emphasis on troubleshooting.

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17

Höving, Stefan, Bastian Oldach, and Norbert Kockmann. "Cooling Crystallization with Complex Temperature Profiles on a Quasi-Continuous and Modular Plant." Processes 10, no. 6 (May 24, 2022): 1047. http://dx.doi.org/10.3390/pr10061047.

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Volatile markets and increasing demands for quality and fast availability of specialty chemical products have motivated the rise of small-scale, integrated, and modular continuous processing plants. As a significant unit operation used for product isolation and purification, cooling crystallization is part of this trend. Here, the small-scale and integrated quasi-continuous filter belt crystallizer (QCFBC) combines cooling crystallization, solid-liquid separation, and drying on a single apparatus. This contribution shows the general working principle, different operation modes, and possibilities of temperature control with the modular setup. For precise temperature control in cooling crystallization, Peltier elements show promising results in a systematic study of different operation parameters. Sucrose/water was used as a model substance system. The results confirm that seed crystal properties are the most important parameter in crystallization processes. Additionally, an oscillating temperature profile has a narrowing effect on the crystal size distribution (CSD). The integrated, small-scale, and modular setup of the QCFBC offers high degrees of flexibility, process control, and adaptability to cope with future market demands.

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Farjas, J., and P. Roura. "Solid-phase crystallization under continuous heating: Kinetic and microstructure scaling laws." Journal of Materials Research 23, no. 2 (February 2008): 418–26. http://dx.doi.org/10.1557/jmr.2008.0045.

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The kinetics and microstructure of solid-phase crystallization under continuous heating conditions and random distribution of nuclei are analyzed. An Arrhenius temperature dependence is assumed for both nucleation and growth rates. Under these circumstances, the system has a scaling law such that the behavior of the scaled system is independent of the heating rate. Hence, the kinetics and microstructure obtained at different heating rates differ only in time and length scaling factors. Concerning the kinetics, it is shown that the extended volume evolves with time according to αex = [exp(κCt′)]m+1, where t′ is the dimensionless time. This scaled solution not only represents a significant simplification of the system description, it also provides new tools for its analysis. For instance, it has been possible to find an analytical dependence of the final average grain size on kinetic parameters. Concerning the microstructure, the existence of a length scaling factor has allowed the grain-size distribution to be numerically calculated as a function of the kinetic parameters.

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Uskoković, V., M.-K. Kim, W. Li, and S. Habelitz. "Enzymatic processing of amelogenin during continuous crystallization of apatite." Journal of Materials Research 23, no. 12 (December 2008): 3184–95. http://dx.doi.org/10.1557/jmr.2008.0387.

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Dental enamel forms through a protein-controlled mineralization and enzymatic degradation process with a nanoscale precision that new engineering technologies may be able to mimic. Recombinant full-length human amelogenin (rH174) and a matrix-metalloprotease (MMP-20) were used in a pH-stat titration system that enabled a continuous supply of calcium and phosphate ions over several days, mimicking the initial stages of matrix processing and crystallization in enamel in vitro. Effects on the self-assembly and crystal growth from a saturated aqueous solution containing 0.4 mg/mL rH174 and MMP-20 with the weight ratio of 1:1000 with respect to rH174 were investigated. A transition from nanospheres to fibrous amelogenin assemblies was facilitated under conditions that involved interaction between rH174 and its proteolytic cleavage products. Despite continuous titration, the levels of calcium exhibited a consistent trend of decreasing, thereby indicating a possible role in protein self-assembly. This study suggests that mimicking enamel formation in vitro requires the synergy between the aspects of matrix self-assembly, proteolysis, and crystallization.

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20

Liu, Zhendong, Kotatsu Okabe, Chokkalingam Anand, Yasuo Yonezawa, Jie Zhu, Hiroki Yamada, Akira Endo, et al. "Continuous flow synthesis of ZSM-5 zeolite on the order of seconds." Proceedings of the National Academy of Sciences 113, no. 50 (November 28, 2016): 14267–71. http://dx.doi.org/10.1073/pnas.1615872113.

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The hydrothermal synthesis of zeolites carried out in batch reactors takes a time so long (typically, on the order of days) that the crystallization of zeolites has long been believed to be very slow in nature. We herein present a synthetic process for ZSM-5, an industrially important zeolite, on the order of seconds in a continuous flow reactor using pressurized hot water as a heating medium. Direct mixing of a well-tuned precursor (90 °C) with the pressurized water preheated to extremely high temperature (370 °C) in the millimeter-sized continuous flow reactor resulted in immediate heating to high temperatures (240–300 °C); consequently, the crystallization of ZSM-5 in a seed-free system proceeded to completion within tens of or even several seconds. These results indicate that the crystallization of zeolites can complete in a period on the order of seconds. The subtle design combining a continuous flow reactor with pressurized hot water can greatly facilitate the mass production of zeolites in the future.

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Christov, Christomir, Christo Balarew, and Stefka Tepavitcharova. "Isomorphic Co-Crystallization of Ammonium and Rubidium Bromocarnallites." Collection of Czechoslovak Chemical Communications 59, no. 8 (1994): 1815–19. http://dx.doi.org/10.1135/cccc19941815.

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The solubility isotherm of the system NH4Br.MgBr2.6 H2O - RbBr.MgBr2.6 H2O - H2O has been investigated at 75 °C and formation of a continuous series of mixed crystals is established. The factors determining the values of the distribution coefficients of the components between the crystalline and liquid phases are discussed.

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Liang, Qiuju, Jie Han, Chunpeng Song, Zaiyu Wang, Jingming Xin, Xinhong Yu, Zhiyuan Xie, Wei Ma, Jiangang Liu, and Yanchun Han. "Tuning molecule diffusion to control the phase separation of the p-DTS(FBTTh2)2/EP-PDI blend system via thermal annealing." Journal of Materials Chemistry C 5, no. 27 (2017): 6842–51. http://dx.doi.org/10.1039/c7tc01763d.

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A bi-continuous phase separation structure of the p-DTS(FBTTh₂)₂/EP-PDI blend system was induced by crystallization of p-DTS(FBTTh₂)₂ confining the EP-PDI molecule diffusion.

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23

Liu, Jiaxu, and Brahim Benyahia. "Systematic Model-Based Steady State and Dynamic Optimization of Combined Cooling and Antisolvent Multistage Continuous Crystallization Processes." Proceedings 62, no. 1 (December 31, 2020): 7. http://dx.doi.org/10.3390/proceedings2020062007.

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Currently, one of the key challenges in the pharmaceutical industry is the transformation of traditional batch production methods into robust continuous processes with the intention of reducing manufacturing costs and time and improving product quality. Crystallization is by far the most important purification technology in Pharma, as more than 80% of the active pharmaceutical ingredients (API) require at least one crystallization step. A successful crystallization process requires tight control over crystal size, shape and polymorphic purity. A rigorous and systematic methodology is presented to design and optimize multistage combined cooling and antisolvent continuous (mixed-suspension, mixed-product removal- MSMPR) crystallizers. The crystallization of acetylsalicylic acid (API) in ethanol (solvent) and water (anti-solvent) is used as a case study. A predictable and validated mathematical model of the system, which consists of a one-dimensional population balance model, was used to develop several optimizations strategies. Firstly, the attainable region of the mean particle size was determined for both minimum and maximum attainable crystal size. The method helped identify the most suitable number of stages and total residence time or volume for a cascade of continuous crystallizers. This was followed by a steady state optimization which helped determine the optimal operating temperatures and antisolvent flowrates. To minimize the startup time, a series of dynamic optimization strategies were implemented, assuming starting from empty vessels. The optimal dynamic profiles of the temperature and antisolvent flow rate, at different crystallization steps, were identified using a systematic and rigorous approach allowing a reduction in the startup time by 31%.

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Acevedo, David, Daniel J. Jarmer, Christopher L. Burcham, Christopher S. Polster, and Zoltan K. Nagy. "A continuous multi-stage mixed-suspension mixed-product-removal crystallization system with fines dissolution." Chemical Engineering Research and Design 135 (July 2018): 112–20. http://dx.doi.org/10.1016/j.cherd.2018.05.029.

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25

Gao, Zhenguo, Yuanyi Wu, Junbo Gong, Jingkang Wang, and Sohrab Rohani. "Continuous crystallization of α-form L-glutamic acid in an MSMPR-Tubular crystallizer system." Journal of Crystal Growth 507 (February 2019): 344–51. http://dx.doi.org/10.1016/j.jcrysgro.2018.07.007.

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Nývlt, Jaroslav. "Effect of Kinetic Parameters on the Dynamicsof Continuous Crystallizers." Collection of Czechoslovak Chemical Communications 63, no. 1 (1998): 121–31. http://dx.doi.org/10.1135/cccc19980121.

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Continuous crystallizers can exhibit periodic cycles of supersaturation, production rate, suspension concentration, crystal size and related quantities. These cycles are most pronounced at the beginning of the crystallization process and depend on the value of kinetic parameters whether they are damped during the run time. Apparently, the cycling behaviour of the crystallizing system depends on the value of ratio of the nucleation and growth exponents n/g. The higher the value of this ratio, the more pronounced is the instability of the system. Admixtures that have a significant effect on the kinetic parameters can dramatically affect the dynamic behaviour of crystallizers so that the steady state may not be established at all.

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Bourguiba, Néji, and Tahar Jouini. "Lignes monovariantes de l'isotherme 75 °C du système quaternaire réciproque: H3PO4–K2SO4–H2SO4–K3PO4–H2O." Canadian Journal of Chemistry 71, no. 11 (November 1, 1993): 1816–20. http://dx.doi.org/10.1139/v93-226.

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The boundary curves and quaternary invariant points of the reciprocal system H3PO4–K2SO4–H2SO4–K3PO4–H2O were investigated at 75 °C and 1 atm by chemical analysis of solutions in equilibria, respectively, with two or three salts. Eleven compounds occur in this system. Only eight of them have crystallization areas inside Janecke's prism; these are K2SO4, K2SO4•KHSO4, K2SO4•7KHSO4•H2O, KHSO4, KH2PO4•KHSO4, KH5(PO4)2, KH2PO4, and a solid solution K8(H2PO4)1+x(HSO4)7−x, 0 ≤ x ≤ 1, of substitution type continuous between the two limiting compositions KH2PO4•7KHSO4 and KH2PO4•3KHSO4. The crystallization fields of 3K2HPO4•KH2PO4•2H2O, K2HPO4, and K3PO4•3H2O are very close to the solubility curves of the ternary system K3PO4–H3PO4–H2O. Results are explained and discussed.

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28

Lee, S., and C. H. Lee. "Scale formation in NF/RO: mechanism and control." Water Science and Technology 51, no. 6-7 (March 1, 2005): 267–75. http://dx.doi.org/10.2166/wst.2005.0646.

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Scale formation of soluble salts is one of the major factors limiting the application of nanofiltration (NF) and reverse osmosis (RO) membranes. This article reviews the scale formation mechanisms in membrane systems, methods to retard scale formation, and a new hybrid system consisting of MF-NF/RO. Two distinct mechanisms in NF/RO fouling by scale formation including surface and bulk crystallization have been identified and investigated. The hydrodynamic operating conditions as well as module geometry determines which fouling mechanism is dominant. An increase in solute concentration at the membrane surface by concentration polarization is responsible for surface crystallization. Conventional methods for scale control only retard the rate of scale formation and their performances are unpredictable. On the other hand, using a MF-NF/RO hybrid system for continuous removal of crystal particles from the retentate stream appears to be effective at high recovery of permeate. When applying the MF-NF/RO hybrid system, substantial improvement in flux is observed in spiral wound module, whereas it is negligible in case of the tubular module. This is because the microfilter could only removes crystals formed in the retentate through the bulk crystallization that is the dominant fouling mechanism in the spiral wound module.

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Acevedo, David, Ramon Peña, Yang Yang, Alastair Barton, Paul Firth, and Zoltan K. Nagy. "Evaluation of mixed suspension mixed product removal crystallization processes coupled with a continuous filtration system." Chemical Engineering and Processing: Process Intensification 108 (October 2016): 212–19. http://dx.doi.org/10.1016/j.cep.2016.08.006.

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Fiorentini, F., M. Cakmak, and S. K. Mowdood. "Influence of Nanosilica Particles on Hysteresis and Strain Induced Crystallization of Natural Rubber as Investigated by a Real Time True Stress-True Strain Birefringence System." Rubber Chemistry and Technology 79, no. 1 (March 1, 2006): 55–71. http://dx.doi.org/10.5254/1.3547929.

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Abstract In this paper, the influence of nanosilica particles on hysteresis and stress induced crystallization of natural rubber compounds is described. For this purpose a newly developed uniaxial stretching system that monitors birefringence, true stress and true strain was used in real time while stretching and retraction is applied to the nanocomposite sheets. This allowed us to link the continuous structural measurements - as represented by birefringence - and the true mechanical properties during the actual stretching and retraction stages as influenced by the presence of nanosilica particles. The birefringence measurement system was also shown to be quite robust in detecting very low levels of retardation prevalent in rubbers. The stress optical behavior of unfilled NR compounds was compared with those filled with 5 phr and 10 phr nanosilica particles. This study allowed the determination of a critical birefringence value above which strain - induced crystallization occurs in the NR compounds. The results indicate that the addition of nanosilica reduces the stress optical constant of natural rubber compounds. In addition, the critical birefringence, above which the strain - induced crystallization occurs, decreases in the presence of 5 phr nanosilica thus indicating the enhancement of the crystallization process at this loading. However, the nanosilica loading beyond 5phr was not found to be a further benefit to strain - induced crystallization mostly because of the introduction of large surface area nanosilica agglomerates that act as a physical barrier between the chains that also most likely suppresses the crosslinking reaction during the preparation.

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Furuta, Masashi, Kouji Mukai, David Cork, and Kazuhiro Mae. "Continuous crystallization using a sonicated tubular system for controlling particle size in an API manufacturing process." Chemical Engineering and Processing: Process Intensification 102 (April 2016): 210–18. http://dx.doi.org/10.1016/j.cep.2016.02.002.

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Petrova, M. A., G. A. Mikirticheva, A. S. Novikova, and V. F. Popova. "Spinel solid solutions in the systems MgAl2O4–ZnAl2O4 and MgAl2O4–Mg2TiO4." Journal of Materials Research 12, no. 10 (October 1997): 2584–88. http://dx.doi.org/10.1557/jmr.1997.0343.

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Phase relations in two binary systems MgAl2O4–ZnAl2O4 and MgAl2O4–Mg2TiO4 have been studied and phase diagrams for them have been constructed. Based on the data of x-ray phase and crystal-optical analyses, the formation of a continuous series of solid solutions with spinel structure between the terminal members of the systems studied has been established. In the MgAl2O4–ZnAl2O4 system the solid solution is stable in the range from room temperature to melting temperature. In the MgAl2O4–Mg2TiO4 system the solid solution decomposes below 1380 °C, yielding the formation of limited regions of homogeneity on the basis of MgAlM2O4 and Mg2+2δ Ti1–δO4. Decomposition of the solid solution is accompanied by crystallization of MgTiO3.

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Stumpf, D., H. Zhu, B. Heinzmann, and M. Kraume. "Phosphorus recovery in aerated systems by MAP precipitation: optimizing operational conditions." Water Science and Technology 58, no. 10 (November 1, 2008): 1977–83. http://dx.doi.org/10.2166/wst.2008.549.

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An attractive way of recovering essential phosphorus from digested sludge of a WWTP is the precipitation in the sludge directly, as part of the continuous treatment process. For optimizing the precipitation, 1 litre-batch tests were performed in a model system to examine the MAP-crystallization kinetics. Different parameters such as e.g. the aeration flow rate were investigated. The aim was to find an optimized setting for a pilot reactor for the continuous production of MAP. This reactor performed as an airlift reactor for an improved mixing and stripping the dissolved CO2 and separating the MAP-crystals. The optimal condition for the airlift pilot reactor is given when the air flow rate for mixing the system and for stripping CO2 for a maximum MAP precipitation is aligned with the particle size distribution.

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Kawachi, Hideo, and Hiroshi Ooshima. "Crystallization of Ergosterol from Hexane Solution by a Continuous Column Crystallizer Equipped with a Water Feeding System." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 39, no. 11 (2006): 1200–1205. http://dx.doi.org/10.1252/jcej.39.1200.

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Peña, Ramon, and Zoltan K. Nagy. "Process Intensification through Continuous Spherical Crystallization Using a Two-Stage Mixed Suspension Mixed Product Removal (MSMPR) System." Crystal Growth & Design 15, no. 9 (August 24, 2015): 4225–36. http://dx.doi.org/10.1021/acs.cgd.5b00479.

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36

Ericsson, Anders, and Martin Fisk. "Modeling of Diffusion-Controlled Crystallization Kinetics in Al-Cu-Zr Metallic Glass." Metals 12, no. 5 (May 19, 2022): 867. http://dx.doi.org/10.3390/met12050867.

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Crystallization is a major challenge in metallic glass production, and predictive models may aid the development of controlled microstructures. This work describes a modeling strategy of nucleation, growth and the dissolution of crystals in a multicomponent glass-forming system. The numerical model is based on classical nucleation theory in combination with a multicomponent diffusion-controlled growth model that is valid for high supersaturation. The required thermodynamic properties are obtained by coupling the model to a CALPHAD database using the Al-Cu-Zr system as a demonstrator. The crystallization of intermetallic Al,CumZrn phases from the undercooled liquid phase were simulated under isothermal as well as rapid heating and cooling conditions (10−1-106Ks−1). The obtained time–temperature transformation and continuous-heating/cooling transformation diagrams agree satisfactorily with the experimental data over a wide temperature range, thereby, demonstrating the predictability of the modeling approach. A comparison of the simulation results and experimental data is discussed.

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Losego, Mark D., and Jamie Wooding. "Crystallization Kinetics in Atomic Layer Deposited (ALD) Thin Films: Opportunities of Time and Chemical Environment." ECS Meeting Abstracts MA2022-02, no. 31 (October 9, 2022): 1149. http://dx.doi.org/10.1149/ma2022-02311149mtgabs.

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Atomic layer deposition (ALD) frequently produces amorphous films, however crystalline phases are often desired for various electrical, chemical, and optical applications. Thus, understanding the fundamental crystallization kinetics of films deposited by ALD is important in designing process pathways to achieve low-temperature crystallization, ultra-thin film (<50 nm) crystallization, controlled microstructures, and epitaxial growth. This presentation will discuss our work to study the crystallization kinetics in ALD TiO2 thin films and challenge some pre-conceived notions about thickness and temperature requirements for ALD film crystallization. We will focus on a prototypical TiO2 ALD process using tetrakis(dimethylamino)titanium(IV) (TDMAT) and water at between 140 °C and 220 °C. Initially, we will discuss data collected on post-deposition, isothermal crystallization kinetics at temperatures ranging from 140 to 200 °C. These time-dependent transformation kinetics are fit to the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, revealing a continuous nucleation process and a two-dimensional growth mechanism, consistent with the observed grain sizes. We also use images collected over short annealing times to independently determine the crystal nucleation rate, which allows us to determine that the activation energies for nucleation (1.32–1.35 eV K-1 atom-1) are about one order of magnitude greater than the activation energies for grain growth (0.12–0.24 eV K-1 atom-1), sugggesting that nucleation is the more significant barrier to crystallization in this system. Finally, we will show how a modification to the process’s chemical environment can lower this barrier to nucleation leading to dramatic in situ crystallization (with no post-deposition annealing) at unusually low process temperatures and film thicknesses (< 15 nm).

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Saputro, Rahmat Hadi, Ryo Matsumura, and Naoki Fukata. "Crystallization Of Tensile Strained n-Type Ge By Continuous Wave Laser Annealing." ECS Meeting Abstracts MA2022-01, no. 29 (July 7, 2022): 1283. http://dx.doi.org/10.1149/ma2022-01291283mtgabs.

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In recent years, germanium (Ge) has attracted a lot of attention for the development of next generation devices due to its higher carrier mobilities compared with silicon (Si) and its compatibility for complementary metal-oxide-semiconductor (CMOS) applications. It is widely known that Ge is an indirect-band semiconductor like Si. However, by introducing tensile strain, the 136 meV difference between direct and indirect gaps can be reduced. Furthermore, in the case of 0.2-0.3% tensile strained Ge, n-type doping in the order of 1019 cm-3 were expected to be resulted in quasi direct-band light emission around 1550 nm wavelength. [1] The realization of this tensile strained n-Ge is promising for the integration of light sources on next generation Ge-based devices. Here, we focused on n-type Ge deposition using molecular beam epitaxy (MBE) method and have succeeded in realizing highly Sb-doped epitaxial n-Ge films by modulating the deposition temperatures. [2] Moreover, we have recently reported the crystallization of amorphous Ge by high-speed continuous wave laser annealing (CWLA), which more importantly also resulted in the introduction of 0.55-0.62% tensile strain. [3] In this study, we applied the similar annealing technique for crystallization of Sb-doped Ge toward the realization of tensile strained n-type Ge films. Sb-doped poly-crystalline Ge films with high Sb concentration (approximately 1019 cm-3) and thickness of about 100 nm were deposited on quartz substrate by molecular beam deposition at 450ºC substrate temperature. Then, 300 nm of SiO2 capping layer was deposited by sputtering in room temperature, such that the sample structure become that shown in Fig.1(a). The samples then annealed in the CWLA system equipped with Nd:YVO4 solid state laser with wavelength of 532 nm as the light source, which scan laser light at the speed (vscan) of 800 m/min. Also, the laser is focused to 20 μm diameter and shifted at 5 μm to scan the samples. Here, the laser power (Elaser) was changed from 300 to 1000 mW. After laser annealing, the capping layer were removed then the samples were characterized by micro-Raman spectroscopy. The annealed sample surface shows brighter contrast compared to the as-deposited samples, as shown in Fig.1(b) and (c), which indicate the structural change of Ge layer. Raman spectra measured at surface of annealed Ge layers are summarized in Fig.2. Here, Ge-Ge peak around 300.2 cm-1 confirmed on the samples, indicating the crystallization of the Ge layers. This peak is not shifted in low Elaser but largely shifted in high Elaser at up to -2.4 cm-1 for undoped and -3.6 cm-1 for the Sb-doped Ge films. This difference could be explained by the liquid phase recrystallization after Ge layer melted in high Elaser (≥600 mW). During recrystallization process, tensile strain is accumulated upon cooling as the tensile strain amount (0.43-0.63%) is agree with the thermal expansion value of Ge between solidification temperature and room temperature (-0.60%). This mechanism is similar to the crystallization of amorphous Ge films on quartz substrates in our previous work. [3] These results show the successful crystallization of tensile strained n-Ge layer by the CWLA method. This finding will be useful for the growth of Ge-based films and a promising step toward the development of CMOS-integrated optoelectronics. Further investigation of the annealing conditions and its relations with the properties of Sb-doped Ge films will be discussed in the main presentation. References Liu, J., Kimerling, L. C. & Michel, J. Semicond. Sci. Technol. 27, (2012). Saputro, R.H., Matsumura, R. & Fukata, N. Cryst. Growth & Des. 21, 6523–6528 (2021). Matsumura, R. & Fukata, N. ECS J. Solid State Sci. Technol. 9, 063002 (2020). Figure 1

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Li, Pengsong, Shiyuan Wang, Imran Ahmed Samo, Xingheng Zhang, Zhaolei Wang, Cheng Wang, Yang Li, et al. "Common-Ion Effect Triggered Highly Sustained Seawater Electrolysis with Additional NaCl Production." Research 2020 (September 24, 2020): 1–9. http://dx.doi.org/10.34133/2020/2872141.

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Developing efficient seawater-electrolysis system for mass production of hydrogen is highly desirable due to the abundance of seawater. However, continuous electrolysis with seawater feeding boosts the concentration of sodium chloride in the electrolyzer, leading to severe electrode corrosion and chlorine evolution. Herein, the common-ion effect was utilized into the electrolyzer to depress the solubility of NaCl. Specifically, utilization of 6 M NaOH halved the solubility of NaCl in the electrolyte, affording efficient, durable, and sustained seawater electrolysis in NaCl-saturated electrolytes with triple production of H2, O2, and crystalline NaCl. Ternary NiCoFe phosphide was employed as a bifunctional anode and cathode in simulative and Ca/Mg-free seawater-electrolysis systems, which could stably work under 500 mA/cm2 for over 100 h. We attribute the high stability to the increased Na+ concentration, which reduces the concentration of dissolved Cl- in the electrolyte according to the common-ion effect, resulting in crystallization of NaCl, eliminated anode corrosion, and chlorine oxidation during continuous supplementation of Ca/Mg-free seawater to the electrolysis system.

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Sonnenschein, Jana, Pascal Friedrich, Moloud Aghayarzadeh, Otto Mierka, Stefan Turek, and Kerstin Wohlgemuth. "Flow Map for Hydrodynamics and Suspension Behavior in a Continuous Archimedes Tube Crystallizer." Crystals 11, no. 12 (November 26, 2021): 1466. http://dx.doi.org/10.3390/cryst11121466.

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The Archimedes Tube Crystallizer (ATC) is a small-scale coiled tubular crystallizer operated with air-segmented flow. As individual liquid segments are moved through the apparatus by rotation, the ATC operates as a pump. Thus, the ATC overcomes pressure drop limitations of other continuous crystallizers, allowing for longer residence times and crystal growth phases. Understanding continuous crystallizer phenomena is the basis for a well-designed crystallization process, especially for small-scale applications in the pharmaceutical and fine chemical industry. Hydrodynamics and suspension behavior, for example, affect agglomeration, breakage, attrition, and ultimately crystallizer blockage. In practice, however, it is time-consuming to investigate these phenomena experimentally for each new material system. In this contribution, a flow map is developed in five steps through a combination of experiments, CFD simulations, and dimensionless numbers. Accordingly, operating parameters can be specified depending on ATC design and material system used, where suspension behavior is suitable for high-quality crystalline products.

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Chen, Xiaoming, Zixian Wang, Ren-Jie Wu, Horng-Long Cheng, and Hsiang-Chen Chui. "Laser-Induced Thermal Annealing of CH3NH3PbI3 Perovskite Microwires." Photonics 8, no. 2 (January 26, 2021): 30. http://dx.doi.org/10.3390/photonics8020030.

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Perovskite microwires have a larger surface-to-volume ratio and better photoelectric conversion efficiency than perovskite films. The degree of crystallization also affects the optoelectrical performances of perovskite microwires. Laser annealing was regarded as a tool for crystallization. High light absorption induced fast heating process. A 405 nm violet laser located near the absorption peak of typical perovskite films was employed as the annealing laser. In an in situ experimental design, the annealing laser beam was combined into the micro Raman measurement system. Real-time information of the annealing and crystallization was provided. Many excellent works were done, and typically needed offline optoelectronic measurements. An mW-level continuous-wave laser beam can provide enough kinetic energy for crystalline in perovskite microwires. The thermal distribution of the perovskite microwire under the annealing laser beams was considered here. Polarized Raman signals can provide evidence of the perovskite microwires crystallization. This work offered the novel approach of an on-site, real-time laser-induced thermal annealing design for perovskite microwires. This approach can be used in other material procedures. Intensity-dependent conditions were crucial for the annealing processes and analyzed in detail. The substrate effect was found. This proposed scheme provided integrated novel, scalable, and highly effective designs of perovskite-based devices.

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Schmalenberg, Mira, Stephanie Kreis, Lena K. Weick, Christian Haas, Fabian Sallamon, and Norbert Kockmann. "Continuous Cooling Crystallization in a Coiled Flow Inverter Crystallizer Technology—Design, Characterization, and Hurdles." Processes 9, no. 9 (August 29, 2021): 1537. http://dx.doi.org/10.3390/pr9091537.

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Continuous small-scale production is currently of utmost interest for fine chemicals and pharmaceuticals. For this purpose, equipment and process concepts in consideration of the hurdles for solids handling are required to transfer conventional batch processing to continuous operation. Based on empirical equations, pressure loss constraints, and an expandable modular system, a coiled flow inverter (CFI) crystallizer with an inner diameter of 1.6 mm was designed. It was characterized concerning its residence time behavior, tested for operation with seed crystals or an ultrasonic seed crystal unit, and evaluated for different purging mechanisms for stable operation. The residence time behavior in the CFI corresponds to ideal plug flow behavior. Crystal growth using seed crystals was demonstrated in the CFI for two amino acids. For fewer seed crystals, higher crystal growth rates were determined, while at the same time, secondary nucleation was observed. Feasibility for the interconnection of a sonicated seeding crystal unit could be shown. However, the hurdles are also identified and discussed. Prophylactic flushing combined with a photosensor for distinguishing between solvent and suspension phase can lead to stable and resource-efficient operation. The small-scale CFI technology was investigated in detail, and the limits and opportunities of the technology are presented here.

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Wierzbowska, Bogusława, Nina Hutnik, Krzysztof Piotrowski, and Andrzej Matynia. "Continuous Mass Crystallization of Vitamin C inl(+)-Ascorbic Acid−Ethanol−Water System: Size-Independent Growth Kinetic Model Approach." Crystal Growth & Design 11, no. 5 (May 4, 2011): 1557–65. http://dx.doi.org/10.1021/cg101521k.

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Quintana-Hernández, Pedro Alberto, Raúl Ocampo-Pérez, Salvador Tututi-Avila, and Salvador Hernández-Castro. "Nonlinear MIMO Control of a Continuous Cooling Crystallizer." Modelling and Simulation in Engineering 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/912071.

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In this work, a feedback control algorithm was developed based on geometric control theory. A nonisothermal seeded continuous crystallizer model was used to test the algorithm. The control objectives were the stabilization of the third moment of the crystal size distribution (μ3) and the crystallizer temperature (T); the manipulated variables were the stirring rate and the coolant flow rate. The nonlinear control (NLC) was tested at operating conditions established within the metastable zone. Step changes of magnitudes ±0.0015 and ±0.5°C were introduced into the set point values of the third moment and crystallizer temperature, respectively. In addition, a step change of ±1°C was introduced as a disturbance in the feeding temperature. Closed-loop stability was analyzed by calculating the eigenvalues of the internal dynamics. The system presented a stable dynamic behavior when the operation conditions maintain the crystallizer concentration within the metastable zone. Closed-loop simulations with the NLC were compared with simulations that used a classic PID controller. The PID controllers were tuned by minimizing the integral of the absolute value of the error (IAE) criterion. The results showed that the NLC provided a suitable option for continuous crystallization control. For all analyzed cases, the IAEs obtained with NLC were smaller than those obtained with the PID controller.

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Mamache, Fateh Enouar, Amar Mesbah, Hanbing Bian, and Fahmi Zaïri. "Micromechanical Modeling of the Biaxial Deformation-Induced Phase Transformation in Polyethylene Terephthalate." Polymers 14, no. 15 (July 26, 2022): 3028. http://dx.doi.org/10.3390/polym14153028.

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In this paper, a micromechanics-based constitutive representation of the deformation-induced phase transformation in polyethylene terephthalate is proposed and verified under biaxial loading paths. The model, formulated within the Eshelby inclusion theory and the micromechanics framework, considers the material system as a two-phase medium, in which the active interactions between the continuous amorphous phase and the discrete newly formed crystalline domains are explicitly considered. The Duvaut–Lions viscoplastic approach is employed in order to introduce the rate-dependency of the yielding behavior. The model parameters are identified from uniaxial data in terms of stress–strain curves and crystallization kinetics at two different strain rates and two different temperatures above glass transition temperature. Then, it is shown that the model predictions are in good agreement with available experimental results under equal biaxial and constant width conditions. The role of the crystallization on the intrinsic properties is emphasized thanks to the model considering the different loading parameters in terms of mechanical path, strain rate and temperature.

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Cai, Zeyun, Bo Song, Longfei Li, Zhen Liu, and Xiaokang Cui. "Effects of B2O3 on Viscosity, Structure, and Crystallization of Mold Fluxes for Casting Rare Earth Alloyed Steels." Metals 8, no. 10 (September 20, 2018): 737. http://dx.doi.org/10.3390/met8100737.

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Amounts of rare earth oxides were transferred into mold fluxes for the continuous casting of rare earth alloyed heavy railway steels. B2O3 was added to improve the viscosity properties and the crystallization behavior of this traditional mold flux. Thus, in this paper, effects of B2O3 on viscosity, structure, and crystallization of CeO2-bearing mold fluxes for casting rare earth alloyed heavy railway steels were investigated by rotating cylinder method, Raman spectroscopy, and magic angle spinning nuclear magnetic resonance (MAS NMR). Experimental results revealed that with the addition of B2O3, viscosity values of mold fluxes at some certain temperatures decreased significantly. By analyzing the structure of glassy mold fluxes, it can be observed that B2O3 behaved as a network-forming oxide within the studied system. However, the introduction of the weak bond energy of B–O and the transition from four-fold coordination boron to three-fold coordination boron with loose structural units mainly reduced the viscosity. Moreover, results of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed that B2O3 decreased the crystallization of the crystal phase Na4Ca4(Si6O18) and the solidus temperature of mold fluxes. Thus, these results obtained can provide guidelines for designing new mold fluxes for casting rare earth alloyed steels.

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Kirdyashkin, А., and A. Kirdyashkin. "Forces generating crystallization differentiation, and the evolution of the melt composition on the example of plagioclase." Transbaikal State University Journal 26, no. 7 (2020): 44–52. http://dx.doi.org/10.21209/2227-9245-2020-26-7-44-52.

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Crystallization differentiation processes in the melt volume are investigated for albite-anorthite continuous solid solution series. It has shown that crystallization differentiation occurs in the isothermal melt volume due to hydrodynamic instability of the melt/solid particles system. The time of particle settling in a 10 cm thick melt layer is estimated for different particle sizes. In terrestrial conditions, the existence of large melt volumes with long lifetime is possible in the case of a long-lived heat source of high thermal power. This source is a mantle thermochemical plume with a mushroom-shaped head. The particle settling time is estimated for the melt layer thickness, i. e. plume head thickness equal to 10 km. A calculation technique is presented for composition of the melt remaining after settling of plagioclase particles. The results of calculations of changes in the melt composition due to crystallization differentiation at a temperature T = 1410 °C and a pressure P = 6,3 kbar are presented. For a melt whose composition corresponds to N 47,5 (weight percentage of anorthite is 47,5 %), the oxide content in the settled plagioclase, the composition of the melt in its intercrystalline spaces, and the residual melt composition are calculated. At constant temperature, the crystallization differentiation of the melt whose composition corresponds to plagioclase leads to the compositional changes in the initial melt. Calculations of the melt composition have shown that the melt is depleted in anorthite component owing to settling of plagioclase particles. The composition of plagioclase therewith shifts to the liquidus line, reaching its limit on this line

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Strugova, Daria, José Carlos Ferreira Junior, Éric David, and Nicole R. Demarquette. "Ultra-Low Percolation Threshold Induced by Thermal Treatments in Co-Continuous Blend-Based PP/PS/MWCNTs Nanocomposites." Nanomaterials 11, no. 6 (June 21, 2021): 1620. http://dx.doi.org/10.3390/nano11061620.

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The effect of the crystallization of polypropylene (PP) forming an immiscible polymer blend with polystyrene (PS) containing conductive multi-wall carbon nanotubes (MWCNTs) on its electrical conductivity and electrical percolation threshold (PT) was investigated in this work. PP/PS/MWCNTs composites with a co-continuous morphology and a concentration of MWCNTs ranging from 0 to 2 wt.% were obtained. The PT was greatly reduced by a two-step approach. First, a 50% reduction in the PT was achieved by using the effect of double percolation in the blend system compared to PP/MWCNTs. Second, with the additional thermal treatments, referred to as slow-cooling treatment (with the cooling rate 0.5 °C/min), and isothermal treatment (at 135 °C for 15 min), ultra-low PT values were achieved for the PP/PS/MWCNTs system. A 0.06 wt.% of MWCNTs was attained upon the use of the slow-cooling treatment and 0.08 wt.% of MWCNTs upon the isothermal treatment. This reduction is attributed to PP crystals’ volume exclusion, with no alteration in the blend morphology.

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Choi, Woohyun, Changyun Park, Yungoo Song, Chaewon Park, Ha Kim, and Chulgyoo Lee. "Sequential Scheelite Mineralization of Quartz–Scheelite Veins at the Sangdong W-Deposit: Microtextural and Geochemical Approach." Minerals 10, no. 8 (July 30, 2020): 678. http://dx.doi.org/10.3390/min10080678.

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The Sangdong W (tungsten)-deposit is known as one of the world’s largest W-deposits, a magmatic–hydrothermal ore deposit including both skarn and hydrothermal alteration zones. The strata-bound characteristic of the deposit resulted in three major orebodies (hanging wall, main, footwall). The main ore mineral is a scheelite (CaWO4)–powellite (CaMoO4) solid solution. We examined the fluid evolution and scheelite formation process of the quartz–scheelite veins of the ore deposit, based on the microtextures and geochemical characteristics of the scheelite. After the initial magmatic–hydrothermal fluid release from the granitic body, prograde skarn is formed. In the later prograde stage, secondary fluid rises and precipitates stage I scheelite. Well-developed oscillatory zoning with the highest Mo content indicates continuous fluid infiltration under an open system. Pressure rises as mineralization occurs, generating the pressure release of the retrograde fluid. Fluid migrates downward by the gravitational backflow mechanism, forming stage II to IV scheelites. Dented oscillatory zoning of stage II scheelite is strong evidence of this pressure release. Stage III and IV scheelite do not show specific internal structures with pure scheelite composition. Retrograde scheelites are formed by fractional crystallization under a closed system. The observation of systematical fractional crystallization in the quartz–scheelite vein system is a meaningful result of our research. The geochemical characteristics and microtextural evidence imprinted in scheelites from each stage provide crucial evidence for the understanding of sequential scheelite mineralization of the quartz–scheelite vein system of the Sangdong W-deposit.

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Parhi, Rabinarayan, and Suryakanta Swain. "Transdermal Evaporation Drug Delivery System: Concept to Commercial Products." Advanced Pharmaceutical Bulletin 8, no. 4 (November 29, 2018): 535–50. http://dx.doi.org/10.15171/apb.2018.063.

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Since two decades or so transdermal route established itself as better alternative to traditional oral route. This is possible due to continuous innovations in transdermal drug delivery (TDD), which not only enables researchers from academia and industry to successfully develop and launch many new pharmaceuticals but also allow to include new classes of drugs that can be developed into transdermal formulations. These successes are achieved due to the use of novel techniques based on either physical or chemical approaches. However, both of these techniques suffer due to their own disadvantages. Comparatively, a simple method of supersaturation to enhance drug permeation across skin has created a new wave of interest. Even though the application supersaturated principle in topical and TDD has been used from 1960s, but proper control of drug release and formation of stable supersaturated states has been the core of intense research in the last decade. Out of various methods used to get supersaturated system, evaporation method is considered as most efficient and practically feasible for TDD. Therefore, in this review concept of supersaturation, selection of solvent system and the mechanism of inhibition of crystallization are discussed. Application of evaporation systems in the development of transdermal formulations such as solutions, semisolids and metered dose therapeutic systems (MDTS) and the commercial evaporative systems are also discussed in this review.

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Journal articles on the topic 'Continuous Crystallization System'

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