Continuous Polymerization Reactor Research Articles

Emulsion polymerisation in continuous reactor systems

AbstractContinuous reactor systems find important applications in the production of sythetic polymer latexes and increased production rates are providing additional incentives for the development of new continuous systems. The fundamental factors that should be considered in the development of continuous processes are reviewed in this paper. Particular emphasis is placed on exploring the differences between batch and continuous reactors and why these difference can lead to different latex product, even if the same recipe is employed. These factors make the task of designing continuous reactor systems based on batch research and development very difficult and risky. Thus it is recommended that small‐scale continuous reactors be employed early in a product/process development effort if that effort is likely to lead to a continuous commercial process.The published literature on continuous emulsion polymerization reactors has been reasonably active in the past ten years. Our understanding of the chemistry and reactor modelling has been advanced but a number of areas for fruitful research remains. Some of these problems are reviewed and directions for new efforts are suggested.

Hierarchical control of a train of continuous polymerization reactors

AbstractA multilayer control scheme is synthesized for a series of polymerization stirred tank reactors to control the monomer conversion over the reactor line. In this work two layers of control are implemented. In the' first level digital PI or self‐tuning regulators (STR) are used to control the reaction temperature of each reactor in the series by manipulating the flowrates of the coolant streams. In the second layer, a locally linear state space model, that can predict the monomer concentration in each reactor, is derived based on steady‐state energy balances. A quadratic performance index is then minimized to obtain the optimal reaction profile that will bring the monomer distribution over the reactor line to its desired target value.

Flow stability of multitubular continuous polymerization reactors

Flow stability of multitubular continuous polymerization reactors

Forced Oscillations in Continuous Polymerization Reactors and Molecular Weight Distribution Control. A Survey

Abstract Several papers have demonstrated that forced periodic operation of chemical reactors is sometimes beneficial in improving the performance of the operation and/or the quality of the final product. See, for example, Refs. 1–4.

THE RESIDENCE TIME DISTRIBUTION FOR LAMINAR FLOW OF NON-NEWTONIAN LIQUIDS THROUGH HELICAL TUBES

Abstract The residence time distribution in a helically coiled tubular reactor is computed for laminar flow of inelastic non-Newtonian liquid at small Dean number. Effect of pseudoplasticity on the residence time distribution is explored. It was found that pseudoplaslicity of the liquid makes the residence time distribution narrower. The effect of dialalant fluid behavior is opposite but very small in magnitude. The results of numerical integrations are correlated with power law index, allowing predictions over a wide range of the index. The results could be used to predict conversion of reactions in a coiled reactor, such as continuous polymerization or fermentation reactors, where the reaction mixtures are likely to be non-Newtonian in nature. Results will be also useful in characterization of coiled chromatographic columns.

The dynamic behavior of continuous polymerization reactors—II Nonisothermal solution homopolymerization and copolymerization in a CSTR

The possible types of dynamic behavior have been determined for a CSTR in which bulk or solution free radical polymerization is carried out. To illustrate the methodology, the expected behavior of reactors for vinyl acetate or methylmethacrylate homopolymerization and vinyl acetate-methylmethacrylate copolymerization has been explicitly determined. The monomer feed ratios, solvent concentrations, and reactor cooling capacity which allow multiple steady states and limit cycles have been carefully mapped.

The dynamic behavior of continuous polymerization reactors—I: Isothermal solution polymerization in a CSTR

A mathematical model having no adjustable parameters is developed and compared with both dynamic and steady-states” in the neighborhood of unstable middle steady states is thought to be due to a combination of methacrylate with ethyl acetate solvent, in a CSTR, was shown to have ignition and hysteresis behavior characteristic of multiple steady states for sufficiently low solvent concentrations. The observation of “pseudosteady-states” in the neighborhood of unstable middle steady states is thought to be due to a combination of kinetic and hydrodynamic mechanisms.

Continuous emulsion polymerization of vinyl acetate. Part I: Experimental studies

AbstractAn interesting feature of commercial continuous emulsion polymerization reactors is the important phenomenon of sustained oscillations. Laboratory investigations of emulsion polymerization in a continuous stirred tank reactor (CSTR) have shown that the conversion, number of polymer particles and other related properties often oscillate widely with time. These oscillations can lead to emulsifier levels too small to adequately cover polymer particles resulting in excessive agglomeration and reactor fouling. Herein is reported an extensive experimental study of vinyl acetate emulsion polymerization in a CSTR. The effects of initiator and emulsifier concentrations, mean residence time and rate of agitation on the production rate and size distribution of polyvinyl acetate latices were investigated. Domains of reactor operation which give rise to sustained oscillations and massive agglomeration of the latex are mapped which give rise to sustained oscillations and massive agglomeration of the latex are mapped out. The effect of different start‐up policies on reactor transients were also investigated.

Multilevel control of a chain of continuous polymerization reactors

Multilevel control of a chain of continuous polymerization reactors

60 The development of a special stirrer device for mixing in homogeneous continuous polymerization reactors

The mixing rate of the special stirrer device was studied on various scales with different stirrer diameters and stirrer speeds; scaling-up procedures were developed. A digital simulation model was set up to study the effects of the stirring parameters on the mixing rate. To study polymerization, the mixing model was combined with a kinetic model of the polymerization reaction. This paper describes the effect of mixing on the frequency distribution of monomers in copolymerization products.

The mathematical modelling of continuous emulsion polymerization reactors: Prediction of multiple steady states and sustained oscillations in methylmethacrylate polymerization

A mathematical model is developed which is shown to represent available literature data on continuous methylmethacrylate polymerization reactors—for

Analysis of the operation of continuous polymerization reactors

A comparative analysis is made of the operation of various polymerization reactors from the point of view of productivity and MWD of products obtained. A study is made of the effect of the distribution of retention times (DRT) on the conversion and MWD of polymers using a “suspension” model of a continuous reactor. “Suspension” and “homogeneous” ideal mixing reactors are compared and the effect of temperature heterogeneities on MWD of polymers, evaluated. In the course of the study two processes—“live” and thermo-initiated radical polymerization of styrene is—are examined in parallel.

A fluid-dynamic study of a continuous polymerisation reactor

The general results of the research conducted on a continuous polymerisation reactor are summarized here. The mathematical model is based on the steady state, two-dimensional set of mass, momentum and energy equations. The pressure gradients are removed from the equations by introducing the stream function and vorticity. The finite-difference analogue of the system has been solved by the Gauss—Seidel technique utilizing the upwind differences for the convective terms. Once all the relevant physical data are available, the complete description of reactor behaviour may be obtained by the exposed procedure. The influence of inlet concentration and temperature on the polymerisation rate is analysed. Relevant phenomena occurring in the core, like hot spot or the appearance of an adiabatic mantle on the wall, are emphasized so to get suggestions for practical operational control.

Forced Oscillations in a Nonisothermal Continuous Polymerization Reactor

Abstract A dynamic model of a nonisothermal continuous stirred tank polymerization reactor is developed to predict product molecular weight distribution parameters. Deliberate oscillations in operating variables were programmed into the model and the resulting time-averaged reactor performance indices compared with that for optimum steady-state operation. Results indicate that periodic operation does influence polymerization reactor performance, particularly with regard to time-averaged molecular weight polydispersity. Significant resonant behavior was encountered with molecular weight properties at low frequencies.

Dynamics of Continuous Stirred-Tank Polymerization Reactor

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDynamics of Continuous Stirred-Tank Polymerization ReactorT. A. Kenat, R. I. Kermode, and S. L. RosenCite this: Ind. Eng. Chem. Process Des. Dev. 1967, 6, 3, 363–370Publication Date (Print):July 1, 1967Publication History Published online1 May 2002Published inissue 1 July 1967https://doi.org/10.1021/i260023a018RIGHTS & PERMISSIONSArticle Views62Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (579 KB) Get e-Alerts

Polymerization Reactor Stability

AbstractIn this paper the methods of non‐linear mechanics have been applied to a continuous well agitated polymerization reactor. Analytical criteria for stability have been derived and phase plots of the full non‐linear equations have been made for monomer collision termination.