Performance comparison of swirl-venturi bubble generator and conventional venturi bubble generator

Wang, Xinyan; Shuai, Yun; Zhou, Xin; Huang, Zhengliang; Yang, Yao; Sun, Jingyuan; Zhang, Haomiao; Wang, Jingdai; Yang, Yongrong

doi:10.1016/j.cep.2020.108022

Cited by 39 publications

(28 citation statements)

References 32 publications

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“…The absorption rate of ethylene was obtained from the flow curve of the outlet, which was recorded by the flowmeter (B). The mass transfer coefficient k L α was calculated from eq where C * was the saturated concentration of dissolved ethylene, C 1 was the concentration of dissolved ethylene at t 1 , C 2 was the concentration of dissolved ethylene at t 2 , t 1 was the initial time of dissolved ethylene, t 2 was the end time of dissolved ethylene, and k L α was the volumetric liquid-side mass transfer coefficient.…”

Section: Methodsmentioning

confidence: 99%

The Intermittent Dormancy of Ethylene Polymerization with the Assistance of Nitrogen Microbubbles

Dai

Chen

et al. 2021

Macromolecules

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The inert nitrogen microbubbles are incorporated during ethylene slurry polymerization to retard the formation of chain entanglements through the intermittent dormancy of living polymer chains. This dormancy effect is endowed by the highly frequent and intensive collisions of countless microbubbles on the growing polyethylene particles, which blocks the transfer channel of reactants on the particle surface. It is evidenced that the transfer barrier slows down the chain propagation and provides extra time for the propagated chains to be crystallized. Thus, the nascent polyethylene with the reduced entanglements and a considerable amount of monoclinic lamellae is achieved by the catalyst with the original ability to synthesize the highly entangled polyethylene. The synchronous increment of stiffness, toughness, and strength is found for the synthesized polyethylene owing to the reduced chain entanglements.

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Section: Methodsmentioning

confidence: 99%

The Intermittent Dormancy of Ethylene Polymerization with the Assistance of Nitrogen Microbubbles

Dai

Chen

et al. 2021

Macromolecules

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“…Type Injector with the speed of airflow rate 0.05 -0.2 Lpm produces bubble diameter range 60 -100 µm [18]. Wang et al, [16,48] using Computational Fluid Dynamics (CFD) generates bubbles ranging from 0 -0.2 mm. Microbubbles ranging in size from 0 to 0.8 millimeters may be generated using the VMG and SVMG microbubble generators [49] [16].…”

Section: Discussionmentioning

confidence: 99%

“…Wang et al, [16,48] using Computational Fluid Dynamics (CFD) generates bubbles ranging from 0 -0.2 mm. Microbubbles ranging in size from 0 to 0.8 millimeters may be generated using the VMG and SVMG microbubble generators [49] [16]. Type Orifice with the speed of airflow rate 1 -4 Lpm produce bubble diameter range 50 -130 µm with CFD [11].…”

Section: Discussionmentioning

confidence: 99%

Effect of Lens Aperture for Analysis of Bubble Image Size Microbubble Generator Aeration System

Taukhid

Trijuno

Karim

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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Investigates Microbubble characterization is an essential component of any experimental investigation of new microbubble generator design. The use of microbubble generators as aeration systems often experiences blockages. That is caused by the broad cross-section of nozzles and air holes with small diameters. The microbubble generator was redesigned by increasing the cross-sectional area and diameter of the air hole. The method of investigating the bubble process uses image capture with three aperture speeds of the lens of 1/125f, 1/160f, and 1/200f with a combined airflow rate of 0.5 Lpm, 1.5 Lpm, and 2.5 Lpm. The result was characterized with multiple lens apertures with 1/160f bubble results ranging from 5.4 - 94.3 μm at all airflow rates.

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“…Taking into consideration that k L α of ethylene was constant throughout the process, eq could be integrated to obtain eq , where k L α is the slope of the line through the origin fitted by ln(( C * – C 1 )/( C * – C 2 )) and ( t 2 – t 1 ) where C 1 is the concentration of dissolved ethylene at t 1 , C 2 is the instantaneous concentration of dissolved ethylene at t 2 , t 1 is the initial time, and t 2 is the instantaneous time.…”

Section: Experimental Sectionmentioning

confidence: 99%

Tailoring the Chain Entanglement by Nitrogen Bubble-Assisted Polymerization

Dai

et al. 2021

Ind. Eng. Chem. Res.

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The reduction in the entangled state of the nascent ultrahigh-molecular-weight polyethylene (UHMWPE) is of fundamental importance to enhance its processability and mechanical properties. However, it remains a challenge to retard the formation of entanglements during polymerization above 60 °C because the chain propagation rate is notably higher than the chain crystallization rate. Herein, we present a feasible method for synthesizing the weakly entangled polyethylene via nitrogen microbubble-assisted polymerization. The mass transfer of ethylene inside the growing polyethylene particles is found to dominate the chain propagation process, which is influenced by the nitrogen bubble size. The contact/interval time (10–3 s) between the microbubbles and the particles, observed by a high-speed camera, appears several orders less than the chain propagation time. Consequently, such frequent contact/separation instantly blocks/recovers the reactant transfer on the solvent–particle interphase, causing an intermittent “dormancy effect” to retard the chain propagation and facilitate the chain crystallization. Therefore, the less entangled polyethylene is synthesized at a relatively high activity.

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Performance comparison of swirl-venturi bubble generator and conventional venturi bubble generator

Cited by 39 publications

References 32 publications

The Intermittent Dormancy of Ethylene Polymerization with the Assistance of Nitrogen Microbubbles

The Intermittent Dormancy of Ethylene Polymerization with the Assistance of Nitrogen Microbubbles

Effect of Lens Aperture for Analysis of Bubble Image Size Microbubble Generator Aeration System

Tailoring the Chain Entanglement by Nitrogen Bubble-Assisted Polymerization

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