Determining the residence time distribution of various screw elements in a co-rotating twin-screw extruder by means of fluorescence spectroscopy

Lepschi, Alexander; Gerstorfer, Gregor; Miethlinger, Jürgen

doi:10.1063/1.4918385

Cited by 8 publications

(14 citation statements)

References 14 publications

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“…The existence of these phenomena and flake flow behavior in the dryer can be evaluated by determining the residence-time distribution (RTD), which is used to diagnose operational problems associated to the flow in continuous systems and to describe material displacement inside equipment by parameters such as external age, mean residence time, variance and standard deviation [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…The determination of the RTD occurs with the feeding of an inert component, named tracer or marker, inside the equipment, at a specific time, and further monitoring of its outlet concentration as a function of time [16,17]. To guarantee the efficiency of the assays, inherent characteristics of the marker must be observed, such as a proper quantification technique, physical and chemical properties similar to the raw materials of the process and the nonadsorption of the material on the inner walls of the equipment [13,[18][19][20]. Additionally, in RTD in-situ determination in industrial processes, it must be guaranteed that the presence of the tracer does not alter the final product characteristics [21].…”

Section: Introductionmentioning

confidence: 99%

“…2 ), obtaining a mean residence time equal to 3.3 min without interruption of the process, maintaining the production without economical losses. Lepschi [13], studying RTD in-situ in a pilot scale extruder for the production of polypropylene (PP), obtained results with a mean residence time of 20 seconds and indications of the influence of the equipment screw configurations on polymer polydispersity. The measurements in-situ occurred with an equipment of fluorescence spectroscopy for the quantification of the tracer composed of a mixture of low concentration of tracking particles and the results varied depending on the operating parameters, which allowed the observation of the optimized conditions of polymer mixture in the equipment.…”

Section: Introductionmentioning

confidence: 99%

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Determination of the residence-time distribution in industrial dryer for the production of recycled polyester

Silva

Carneiro

Firmani

et al. 2021

CI&CEQ

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The study proposes the evaluation of the residence-time distribution (RTD) in-situ in an industrial dryer for the production of recycled polyester fibers (PES) from colorless polyethylene terephthalate (PET) flakes without interruption of the production. A disturbance of the pulse type was employed, in which the tracer (blue PET flakes) had previously been crystalized and its concentration was obtained according to the time at the dryer outlet. Additionally, analyses of intrinsic viscosity and crystallization percentage of the PET flakes (colorless and blue) and PES intrinsic viscosity and color force were performed. By RTD, the mean residence time (322.8 min), the variance (1305.4 min2), the standard deviation (36.1 min) and the relative error (1.5%) were obtained when compared to the theoretical residence time, indicating the absence of preferred paths or flake agglomerates in the equipment. Finally, the characterization demonstrated that there was no alteration in the parameters of product quality during RTD evaluation, confirming the potential of application of this methodology for diagnoses of continuous industrial processes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of the residence-time distribution in industrial dryer for the production of recycled polyester

Silva

Carneiro

Firmani

et al. 2021

CI&CEQ

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“…Residence time distribution refers to the time when material particles remain in a reactor from the starting point to the exit point. During extrusion process, the residence time distribution of the fluid not only characterizes the axial mixing capacity of the extruder but also directly affects the flow time and dispersive capacity of a polymer melt [9][10][11]; as such, residence time distribution is an important parameter of a polymer in the melt processing of single-screw extruders [12][13][14][15]. Residence time can be measured indirectly and directly, usually via a tracer [16,17].…”

Section: Introductionmentioning

confidence: 99%

Preparation and application of macromolecules with a fluorescence effect in polymer processing

Chen

Guo

Chen

et al. 2019

Designed Monomers and Polymers

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In this study, 9-anthracenemethyl methacrylate (AMMA) and styrene (St) as monomers and benzoyl peroxide as an initiator were used to synthesize P(St-co-AMMA), a macromolecule tracer with a fluorescence effect, via free radical copolymerization. A fluorescent online detection device was built on the basis of the principle of fluorescence online detection by using the single-screw extrusion platform of a torque rheometer to explore the effect of the amount of macromolecular tracer and screw speed on the residence time distribution of polystyrene in single-screw extrusion. Fourier transform infrared spectroscopy, 1H-NMR, thermal stability, fluorescence properties, and rheological properties show that the resulting product P(St-co-AMMA) has a degree of thermal stability, fluorescence, and rheological properties similar to polystyrene, so this product can be used to characterize the residence time distribution during single-screw extrusion. The amount of macromolecular tracer P(St-co-AMMA) does not affect the residence time distribution of polystyrene during single-screw extrusion processing, meanwhile, the minimum residence time decreases and the residence time distribution becomes narrow as the screw speed increases, that is, the axial mixing capacity of the single-screw extruder decreases as the screw speed increases.

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“…The reflected spectrum was evaluated in MATLAB. The extruder screw-in can be fixed in a ½" -20 UNF hole, or to the end to measure at the polymer strand [7,8].…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

Fiber length shortening and fluorescence spectroscopy as characterization method for distributive and dispersive mixing in a co-rotating twin screw extruder

Lepschi¹,

Burzic²,

Sobczak³

et al. 2016

AIP Conference Proceedings

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Determining the residence time distribution of various screw elements in a co-rotating twin-screw extruder by means of fluorescence spectroscopy

Cited by 8 publications

References 14 publications

Determination of the residence-time distribution in industrial dryer for the production of recycled polyester

Determination of the residence-time distribution in industrial dryer for the production of recycled polyester

Preparation and application of macromolecules with a fluorescence effect in polymer processing

Fiber length shortening and fluorescence spectroscopy as characterization method for distributive and dispersive mixing in a co-rotating twin screw extruder

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