Some aspects of nonisothermal crystallization of polymers. III. Crystallization during melt spinning

Nakamura, Katsuyuki; Watanabe, T.; Amano, Toshihiko; Katayama, Ken‐ichi

doi:10.1002/app.1974.070180223

Cited by 49 publications

(22 citation statements)

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“…This is in agreement with the mechanism of ethylene copolymers as wax inhibitors [36]. A reasonable judgement can be obtained that the WAT and wax crystals cannot be modified with the contrast additive, because it cannot lower the pour point of crude oils as presented above Furthermore, the crystallization of waxes is a kinetic process, the onset of which can be described by the classical Avrami equation [37]:…”

Section: Effect Of the Drag-reducing Surfactant On Wax Crystals' Agglsupporting

confidence: 86%

The Use of Biobased Surfactant Obtained by Enzymatic Syntheses for Wax Deposition Inhibition and Drag Reduction in Crude Oil Pipelines

Wang

et al. 2016

Catalysts

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Abstract:Crude oil plays an important role in providing the energy supply of the world, and pipelines have long been recognized as the safest and most efficient means of transporting oil and its products. However, the transportation process also faces the challenges of asphaltene-paraffin structural interactions, pipeline pressure losses and energy consumption. In order to determine the role of drag-reducing surfactant additives in the transportation of crude oils, experiments of wax deposition inhibition and drag reduction of different oil in pipelines with a biobased surfactant obtained by enzymatic syntheses were carried out. The results indicated that heavy oil transportation in the pipeline is remarkably enhanced by creating stable oil-in-water (O/W) emulsion with the surfactant additive. The wax appearance temperature (WAT) and pour point were modified, and the formation of a space-filling network of interlocking wax crystals was prevented at low temperature by adding a small concentration of the surfactant additive. A maximum viscosity reduction of 70% and a drag reduction of 40% for light crude oil flows in pipelines were obtained with the surfactant additive at a concentration of 100 mg/L. Furthermore, a successful field application of the drag-reducing surfactant in a light crude oil pipeline in Daqing Oilfield was demonstrated. Hence, the use of biobased surfactant obtained by enzymatic syntheses in oil transportation is a potential method to address the current challenges, which could result in a significant energy savings and a considerable reduction of the operating cost.

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Section: Effect Of the Drag-reducing Surfactant On Wax Crystals' Agglsupporting

confidence: 86%

The Use of Biobased Surfactant Obtained by Enzymatic Syntheses for Wax Deposition Inhibition and Drag Reduction in Crude Oil Pipelines

Wang

et al. 2016

Catalysts

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“…(3), (8), or (14)) and compare the results with typical values expected for crystallization after a previous nucleation stage (n = m) or simultaneous nucleation and growth (n = m + 1).…”

Section: Interpretation Of Differential Thermal Analysis/differenmentioning

confidence: 96%

“…The activation energy and the pre-exponential factor K v in Eq. (8) can also be related to the corresponding kinetic constant for isothermal crystallization (Eq. (2)).…”

Section: (1) Case A1: Isothermal Nucleation Stagementioning

confidence: 99%

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Crystallization with Variable Temperature: Corrections for the Activation Energy

Frade

1998

Journal of the American Ceramic Society

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The Nakamura-Avrami method has been revised to derive reliable solutions for describing the kinetics of crystallization on heating with variable temperature. The corresponding numerical solutions for first-order phase-boundarycontrolled growth were computed to evaluate the errors that should be expected when using simple approximate solutions. The relative differences increased as the average dimensionless temperature increased; thus, a method was proposed to obtain correct values for the activation energy and pre-exponential factors. Our analysis of the effects of heating rate on the crystallization peak is consistent with the Kissinger equation, even for dimensionality values of >1. Numerical solutions were also used to demonstrate the validity of the Kissinger equation.

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“…There have been some studies of heat transfer during crystallization in molding which do consider thickness effects [7,8]. Nakamura et al [9] made an effort to consider a radial variation of temperature and crystallization in fiber spinline crystallization in a 1974 paper. Fundamental studies of the detailed character of crystallization in thick sections in processing operations only occurred in the 1980s with the work of Eder and Janeschitz-Kriegl [10,11] and Berger and Schneider [12] for crystallization in slabs.…”

Section: Introductionmentioning

confidence: 98%

Modeling Heat Transfer with Crystallization in Rods and Filaments

White

Choi

2001

International Polymer Processing

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A study of modeling heat transfer with crystallization in thick rods is described. We apply a formulation due to Nakamura et al. and Berger and Schneider to determine the temperature profiles through a thick rod. This involves a non-homogeneous cylindrical coordinate heat conduction equation with a heat of crystallization source term. The partial differential equation describing the temperature profile is represented in terms of dimensionless groups characterizing the ratios of heat of crystallization, surface heat transfer, and thermal inertia to heat conduction. These dimensionless groups are used to characterize the solutions of this equation. Different solution regimes are predicted. The application to radial temperature profiles during melt spinning of polymer filaments is described.

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Some aspects of nonisothermal crystallization of polymers. III. Crystallization during melt spinning

Cited by 49 publications

References 1 publication

The Use of Biobased Surfactant Obtained by Enzymatic Syntheses for Wax Deposition Inhibition and Drag Reduction in Crude Oil Pipelines

The Use of Biobased Surfactant Obtained by Enzymatic Syntheses for Wax Deposition Inhibition and Drag Reduction in Crude Oil Pipelines

Crystallization with Variable Temperature: Corrections for the Activation Energy

Modeling Heat Transfer with Crystallization in Rods and Filaments

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