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Xiao H, Zhang Y, Wang J. Correlating measurement qualities of cross-correlation based solids velocimetry with solids convection-mixing competing mechanism in different gas fluidization regimes. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Bernardo F, Covas JA, Canevarolo SV. On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders. Polymers (Basel) 2022; 14:polym14061152. [PMID: 35335483 PMCID: PMC8948841 DOI: 10.3390/polym14061152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 01/27/2023] Open
Abstract
The use of real-time techniques to evaluate the global mixing performance of co-rotating twin-screw extruders is well consolidated, but much less is reported on the specific contribution of individual screw zones. This work uses on-line flow turbidity and birefringence to ascertain the mixing performance of kneading blocks with different geometries. For this purpose, one of the barrel segments of the extruder was modified in order to incorporate four sampling devices and slit dies containing optical windows were attached to them. The experiments consisted in reaching steady extrusion and then adding a small amount of tracer. Upon opening each sampling device, material was laterally detoured from the local screw channel, and its turbidity and birefringence were measured by the optical detector. Residence time distribution curves (RTD) were obtained at various axial positions along three different kneading blocks and under a range of screw speeds. It is hypothesized that K, a parameter related to the area under each RTD curve, is a good indicator of dispersive mixing, whereas variance can be used to assess distributive mixing. The experimental data confirmed that these mixing indices are sensitive to changes in processing conditions, and that they translate the expected behavior of each kneading block geometry.
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Affiliation(s)
- Felipe Bernardo
- Graduate Program in Materials Science and Engineering, Federal University of São Carlos, Rod. Washington Luiz, km 235 SP-310, São Carlos 13565-905, Brazil;
| | - José A. Covas
- Institute for Polymers and Composites (IPC), University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal
- Correspondence: (J.A.C.); (S.V.C.)
| | - Sebastião V. Canevarolo
- Department of Materials Engineering, Federal University of São Carlos, Rod. Washington Luiz, km 235 SP-310, São Carlos 13565-905, Brazil
- Correspondence: (J.A.C.); (S.V.C.)
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Canevarolo SV, Mélo TJA, Covas JA, Carneiro OS. Direct Method for Deconvoluting Two Residence Time Distribution Curves. INT POLYM PROC 2022. [DOI: 10.1515/ipp-2001-0004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
A pair of related Residence Time Distribution (RTD) curves obtained experimentally during extrusion, are deconvoluted using a methodology based on the concept of equivalent residence times. Two points of two RTD curves are equivalent when the same percentage of tracer has exited the system. The time scale of the deconvoluted curve is obtained by subtracting the two equivalent time values of the available RTD curves. The method was tested using simulated pulse-shaped RTD curves and also carrying out measurements on a twin screw extruder. Despite the experimental errors involved, the two tests seem to demonstrate the usefulness of the approach.
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Affiliation(s)
- S. V. Canevarolo
- Universidade Federal de São Carlos, Departamento de Engenharia de Materiais , São Carlos , Brazil
| | | | - J. A. Covas
- Department of Polymer Engineering, University of Minho , Guimarães , Portugal
| | - O. S. Carneiro
- Department of Polymer Engineering, University of Minho , Guimarães , Portugal
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Bauer H, Matić J, Evans RC, Gryczke A, Ketterhagen W, Sinha K, Khinast J. Determining local residence time distributions in twin-screw extruder elements via smoothed particle hydrodynamics. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2021.117029] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mechanistic modeling of modular co-rotating twin-screw extruders. Int J Pharm 2014; 474:157-76. [PMID: 25102114 DOI: 10.1016/j.ijpharm.2014.08.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 08/03/2014] [Indexed: 11/20/2022]
Abstract
In this study, we present a one-dimensional (1D) model of the metering zone of a modular, co-rotating twin-screw extruder for pharmaceutical hot melt extrusion (HME). The model accounts for filling ratio, pressure, melt temperature in screw channels and gaps, driving power, torque and the residence time distribution (RTD). It requires two empirical parameters for each screw element to be determined experimentally or numerically using computational fluid dynamics (CFD). The required Nusselt correlation for the heat transfer to the barrel was determined from experimental data. We present results for a fluid with a constant viscosity in comparison to literature data obtained from CFD simulations. Moreover, we show how to incorporate the rheology of a typical, non-Newtonian polymer melt, and present results in comparison to measurements. For both cases, we achieved excellent agreement. Furthermore, we present results for the RTD, based on experimental data from the literature, and found good agreement with simulations, in which the entire HME process was approximated with the metering model, assuming a constant viscosity for the polymer melt.
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Fel E, Massardier V, Mélis F, Vergnes B, Cassagnau P. Residence Time Distribution in a High Shear Twin Screw Extruder. INT POLYM PROC 2014. [DOI: 10.3139/217.2805] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The residence time distributions (RTD) of a high shear twin screw extruder were measured by an on–line UV fluorescence device. First, by increasing throughput (Q) and screw speed (N), a decrease of the complex viscosity of the studied polypropylene (PP) was observed, revealing chain scissions. It was associated to high viscous dissipation taking place during extrusion, and more particularly under high shear conditions. Then the impact of these experimental conditions on the RTD was carried out. As expected, an increase of usual throughputs and screw speeds decrease mostly the RTD characteristic data. In this study industrial rate have been studied: throughput varied from 1.5 up to 22 kg h−1 and screw speed varied from 200 min−1 up to 1 200 min−1. However, by increasing the screw speed over usual values (from 500 up to 1 200 min−1), the variation of some experimental RTD characteristics were unexpected. Indeed, the slope of the shape of the experimental RTD function E(t) changed significantly. This phenomenon will be called lag or delay time. This result was only observed at low throughputs and high screw rotation speeds. To finish, a modeling software of twin screw extrusion process was used to compare experimental and calculated results. For usual processing conditions (up to 700 min−1), the simulation predicts nicely the experimental RTDs. However, at high screw speed (N > 800 min−1) and moderate throughput (Q = 4 kg h−1), the simulation fails to predict the RDT delay time. Hence, some side effects apparently occurred during high shear extrusion at low throughputs.
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Affiliation(s)
- E. Fel
- INSA-Lyon , CNRS UMR 5223, Ingénierie des Matériaux Polymères, Villeurbanne , France
| | - V. Massardier
- INSA-Lyon , CNRS UMR 5223, Ingénierie des Matériaux Polymères, Villeurbanne , France
| | - F. Mélis
- Université de Lyon , CNRS UMR 5223, Ingénierie des Matériaux Polymères, Villeurbanne , France
| | - B. Vergnes
- MINES ParisTech , Centre de Mise en Forme des Matériaux (CEMEF), UMR CNRS 7635, Sophia-Antipolis , France
| | - P. Cassagnau
- Université de Lyon , CNRS UMR 5223, Ingénierie des Matériaux Polymères, Villeurbanne , France
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RazaviAghjeh MK, Nazockdast H, Assempour H. Determination of the Residence Time Distribution in Twin Screw Extruders via Free Radical Modification of PE. INT POLYM PROC 2013. [DOI: 10.3139/217.1842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The main objective of the present work was to introduce an inline method for measuring the residence time distribution (RTD) of twin screw extruders on the basis of information obtained from the melt free radical modification of polyethylene in a modular intermeshing co-rotating twin screw extruder. The trend of increasing rate of the extruder total torque resulted from replacing the neat polyethylene feed by a mixture of polyethylene and reactants which are chemically capable of creating chainbranching and/or crosslinking reactions was considered as the main information source for evaluating the RTD of the extruder. The RTD results were compared with those obtained from the tracer pulse input method, and good agreement was found. It was also demonstrated that, the present in-line RTD measuring technique has reliability of following the effect of feeding rate, screw speed and reactant concentration on the RTD of the twin screw extruders. It was found that, increasing the feeding rate results in decreasing the minimum residence time, and results in a narrower RTD. At constant feeding rate increasing the screw speed decreased the minimum residence time and broadened the RTD. The results also showed that, reactant concentration and variation of the viscosity along the screw have not appreciable effect on the twin screw extruders RTD.
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Affiliation(s)
- M. K. RazaviAghjeh
- Polymer Engineering Department, Amir Kabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - H. Nazockdast
- Polymer Engineering Department, Amir Kabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - H. Assempour
- Polymer Engineering Department, Amir Kabir University of Technology (Tehran Polytechnic), Tehran, Iran
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Cassagnau P, Bounor-Legaré V, Fenouillot F. Reactive Processing of Thermoplastic Polymers: A Review of the Fundamental Aspects. INT POLYM PROC 2013. [DOI: 10.3139/217.2032] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The review is devoted to the fundamental aspects of the reactive processing of thermoplastic polymers. First of all, some reactive processing examples, including polymer grafting (vinyl silane, maleic anhydride) and/or functionalization, bulk polymerization (urethane, lactams, acrylate, ∊-capolactone), polyester modification and new copolymers synthesis, are presented. From a fundamental point of view, the review covers the state of the art in the domains of rheology (specifically modelling of rheo-kinetics), diffusion and mixing in highly viscous reactive or non reactive media. Finally, 1, 2 and 3-D simulation of the reactive extrusion process in twin-screw extruder is reported at the end of the review.
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Affiliation(s)
- P. Cassagnau
- Université de Lyon, Lyon, France, IML/LMPB UMR-CNRS #5223, Ingénierie des Matériaux Polymères: Laboratoire desMatériaux Polymères et Biomatériaux, Villeurbanne, France
| | - V. Bounor-Legaré
- Université de Lyon, Lyon, France, IML/LMPB UMR-CNRS #5223, Ingénierie des Matériaux Polymères: Laboratoire desMatériaux Polymères et Biomatériaux, Villeurbanne, France
| | - F. Fenouillot
- Ingénierie des Matériaux Polymères: Laboratoire des Matériaux Macromoléculaires, IMP/LMM UMR-CNRS #5223, INSA-Lyon, 69621 Villeurbanne cedex – France
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Lee KT, Ingram A, Rowson NA. Twin screw wet granulation: The study of a continuous twin screw granulator using Positron Emission Particle Tracking (PEPT) technique. Eur J Pharm Biopharm 2012; 81:666-73. [DOI: 10.1016/j.ejpb.2012.04.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 04/04/2012] [Accepted: 04/18/2012] [Indexed: 11/28/2022]
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Liu HY, Yao Z, Cao K, Li BG. Characteristic analysis on a reactive extrusion process for the imidization of poly(styrene-co-maleic anhydride) with aniline. Chem Eng Sci 2010. [DOI: 10.1016/j.ces.2009.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Zhang XM, Feng LF, Hoppe S, Hu GH. Local residence time, residence revolution, and residence volume distributions in twin-screw extruders. POLYM ENG SCI 2007. [DOI: 10.1002/pen.20812] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Qu J, Feng Y, He H, Jin G, Cao X. Effect of the axial vibration of screw on residence time distribution in single-screw extruders. POLYM ENG SCI 2005. [DOI: 10.1002/pen.20457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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van den Einde R, Kroon P, van der Goot A, Boom R. Local mixing effects of screw elements during extrusion. POLYM ENG SCI 2005. [DOI: 10.1002/pen.20268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Poulesquen A, Vergnes B, Cassagnau P, Michel A, Carneiro OS, Covas JA. A study of residence time distribution in co-rotating twin-screw extruders. Part II: Experimental validation. POLYM ENG SCI 2004. [DOI: 10.1002/pen.10157] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Poulesquen A, Vergnes B. A study of residence time distribution in co-rotating twin-screw extruders. Part I: Theoretical modeling. POLYM ENG SCI 2004. [DOI: 10.1002/pen.10156] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Influence of maleic anhydride grafting on the rheological properties of polyethylene terephthalate–styrene butadiene blends. POLYMER 2001. [DOI: 10.1016/s0032-3861(01)00197-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Santos DM, Canevarolo Jr SV. Sistema portátil para medida on-line da distribuição de tempo de residência na extrusão. POLIMEROS 1999. [DOI: 10.1590/s0104-14281999000200014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A Curva de Distribuição de Tempos de Residência - CDTR tem sido largamente usada para caracterização do tipo de fluxo em extrusoras, sendo que medidas "on-line" permitem diagnosticar de modo muito rápido problemas como desgaste entre a rosca e o barril da extrusora, estagnação do material e outros. A CDTR pode ser determinada fazendo-se uso da técnica de estímulo de pulso único, onde um traçador é introduzido no sistema em um dado instante e sua concentração é estimada na saída. Este artigo propõe um sistema portátil de medida "on-line" feito através da variação da luz transmitida medida com um detector constituído por uma fonte de radiação visível e uma célula fotoelétrica e um software de coleta e tratamento de dados. Usando-se este sistema em uma extrusora de dupla rosca co-rotacional interpenetrante, pode-se verificar que a CDTR é muito mais sensível à variações na taxa de alimentação do que da velocidade de rotação da rosca e que as frações mais lentas do traçador podem demorar quatro vezes mais que as mais rápidas para saírem. Aumento na velocidade de rotação da rosca e/ou redução na taxa de alimentação aumenta o fluxo axial alargando a CDTR.
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