Film flow on rotating wheel in a horizontal twin-shaft reactor for polymer devolatilization

Cheng, Wenkai; Wang, Jiajun; Gu, Xue‐Ping; Feng, Lianfang

doi:10.1016/j.ces.2018.07.011

Cited by 16 publications

(14 citation statements)

References 21 publications

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“…The b* (Table ) of PET rises with the increasing of melt film thickness, when the color of the sample turns yellow, it indicates that the degradation reaction is enhanced. Therefore, in actual production, a new insight is to design a polycondensation reactor with providing a large specific surface area as much as possible, such as film‐forming reactor …”

Section: Resultsmentioning

confidence: 99%

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Film reaction kinetics for melt postpolycondensation of poly(ethylene terephthalate)

Chen

Song

Guang

et al. 2020

J of Applied Polymer Sci

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Melt polycondensation has recently been reported to prepare high‐viscosity poly(ethylene terephthalate) (PET), the reaction efficiency is greatly improved in over 10‐folds compared with conventional solid state polycondensation (SSP). Melt postpolycondensation of common PET chips was conducted in specified film thickness to obtain industrial PET. Based on the investigation of reaction conditions, film reaction kinetics were determined in the principle of end groups analysis. It was positively regulated that the intrinsic viscosity of PET could be achieved in condition of high vacuum, thin melt film and proper temperature, degradation reaction would be increased at exorbitant temperature. An apparent reaction kinetic model was proposed and was verified by experiments. Results indicated the activation energy of melt postpolycondensation of PET was 88.22 kJ/mol and the reaction rate constant was significant higher than that of solid state polycondensation.

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Section: Resultsmentioning

confidence: 99%

“…Therefore, in actual production, a new insight is to design a polycondensation reactor with providing a large specific surface area as much as possible, such as film-forming reactor. [29,30]…”

Section: Effect Of Melt Film Thicknessmentioning

confidence: 99%

Film reaction kinetics for melt postpolycondensation of poly(ethylene terephthalate)

Chen

Song

Guang

et al. 2020

J of Applied Polymer Sci

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“…Hence, there exists a minimum rotating speed (N min ) for the unbounded film formation, which decreases sharply as fluid viscosity increases. 14 The minimum rotating speed for axial unbounded film formation on the kneading bar (the red curve in Figure 6) is larger than that for the radial unbounded film in the open window on the disk element (the black curve in Figure 6). Their difference tends to decrease with the increasing fluid viscosity.…”

Section: Methodsmentioning

confidence: 93%

“…The film formation process on the disk element is much similar to that on the rotating wheel. 14 There exist the unbounded film and bounded film on the rotating wheel. Films on the spoke and ring zone are bounded films, while films in the open window are unbounded films.…”

Section: Methodsmentioning

confidence: 99%

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Film Formation and Mass Transfer Characteristics in a Horizontal Self-Cleaning Twin-Shaft Kneader with Highly Viscous Newtonian Fluids

Cheng

Wang

et al. 2021

Ind. Eng. Chem. Res.

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The visual experimental technique was used to investigate the film formation process in a horizontal self-cleaning twin-shaft kneader with highly viscous Newtonian fluids. The absorption of CO2 in syrup solution was adopted to study the mass transfer characteristics. There exist a radial unbounded film and bounded film on the disk element, while an axial unbounded film and bounded film are generated on the kneading bar. The minimum rotating speed for the axial unbounded film formation on the kneading bar is higher than that for the radial unbound film formation on the disk element. The twin-shaft kneader possesses much better mass transfer performance than the twin-shaft wheel reactor.

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Hydrodynamics and film formation characteristics in a horizontal self‐cleaning twin‐shaft kneader for polymer devolatilization

Liao

Hong³

et al. 2022

J of Applied Polymer Sci

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A deep understanding of hydrodynamics and film formation characteristics is a prerequisite for the design of twin‐shaft kneaders. In this work, the hydrodynamics and film formation characteristics of a self‐cleaning twin‐shaft kneader are investigated using computational fluid dynamics method. Because of the intermeshing interaction and scratching action of the kneader rods, both bounded films and free films coexist in the kneader. Since both shafts rotate clockwise, more liquid is accumulated in the left cylinder. The liquid level of the left cylinder is higher which reduces the film formation rate of the left zone. The film formation rate in the right zone is 1.3–1.8 times that of the left zone and overlapping zone. The differences between the left and right cylinders would cause inconsistent devolatilization performances. To reduce the negative effects of asymmetric level, a static kneading rod is used to reduce the liquid level of the left zone and increase the film formation rate by 15%. We notice that adding a static kneading rod reduces the power consumption by 10%–30% compared with increasing the rotating speed to the same film formation rate. It could be an efficient method for polymer devolatilization.

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Film flow on rotating wheel in a horizontal twin-shaft reactor for polymer devolatilization

Cited by 16 publications

References 21 publications

Film reaction kinetics for melt postpolycondensation of poly(ethylene terephthalate)

Film reaction kinetics for melt postpolycondensation of poly(ethylene terephthalate)

Film Formation and Mass Transfer Characteristics in a Horizontal Self-Cleaning Twin-Shaft Kneader with Highly Viscous Newtonian Fluids

Hydrodynamics and film formation characteristics in a horizontal self‐cleaning twin‐shaft kneader for polymer devolatilization

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