Hydrodynamics and mass transfer enhancement of gas–liquid flow in micropacked bed reactors: Effect of contact angle

Micro‐packed bed reactor (μPBR) presents great potential in the field of multiphase reactions due to the features of safety and high efficiency. However, the deeper cognition of mass transfer needs to be taken into consideration that is the foundation of reactor design. In this work, local and global gas–liquid mass transfer in the μPBR were studied utilizing a noninvasive colorimetric technique. In reactor level, the qualitative and quantitative comparisons were conducted; in particle level, liquid flow and mass transfer textures were assessed for the first time. The diversities of local mass transfer characteristics from temporal and spatial dimensions were obtained, and the heterogeneity of local and global mass transfer was revealed. The predicted correlations of in μPBR with churn flow and pseudo‐static flow were established with deviations generally within ±18%. This study contributes to improve the understanding of mass transfer and points out the process intensification direction of μPBR.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Local and global gas–liquid mass transfer in a micro‐packed bed reactor utilizing a noninvasive colorimetric technique

Liu,

Xie,

Luo

et al. 2023

Liquid holdup of gas–liquid two‐phase flow in micro‐packed beds reactors

Chen,

2024

Liquid holdup is a crucial factor in the study of hydrodynamic behaviors in the micro‐packed bed reactor (μPBR). In this work, the values of liquid holdup are studied with the weighing method with good accuracy. The packed bed is a tube made of stainless steel with a length of 20 cm and an inner diameter of 4 mm, packed with 177–250 μm or 350–500 μm microbeads. The gas and liquid flow rates vary from 5 to 20 mL/min and 0.25 to 2 mL/min, respectively. A new hypothesis of the flow regions is proposed based on the experimental results. Furthermore, a new set of empirical correlation is built with great agreement, particularly for viscous liquids, whose viscosity ranges from 0.99 to 5.98 mPa·s, showing an atypical tendency.

The contact angle and structure of water on the graphite‐like substrate: A classical density functional approach

Sang,

Wei,

Jin

2024

The influences of temperature and water−graphite interaction energy on the contact angle (θ) and structure of water on the graphite‐like substrate have been investigated using the classical density functional theory. We find that the temperature‐dependent behavior of cosθ is contingent upon the water−graphite interaction energy, manifesting in three distinct patterns: increasing, decreasing, or remaining nearly invariant with temperature within the examined range (273.16–640K). Furthermore, a novel simple equation has been derived to describe the temperature‐dependent variation of cosθ at constant water−graphite interaction energy, that is, , where is the water−vapor interfacial tension, and the value of depends on the water−graphite interaction energy. According to different values of , this equation is able to successfully represent the three aforementioned patterns. At last, the density profile and hydrogen bonding structure of water near the substrate have been analyzed to offer microscopic insights.