Investigation of pulsing flow regime transition and pulse characteristics in trickle-bed reactor by electrical resistance tomography

Zhao, Tong; Eda, Takeshi; Sapkota, Achyut; Haruta, Jun; Nishio, Masayuki; Takei, Masahiro

doi:10.1016/j.ces.2015.03.010

Cited by 22 publications

(34 citation statements)

References 31 publications

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“…Gas invasion in liquid-saturated porous media has been widely studied over the past years, and is still an active research topic, due to its numerous applications in many different fields. Phenomena like air sparging [1][2][3], CO 2 sequestration [4], catalytic processes [5] or hydrothermal complexes [6,7], methane venting areas [8][9][10], and volcanic events [11][12][13] are among the many industrial and geophysical fields governed by such processes. A classical approach to understand and predict the dynamics of fluid invasion has been to consider a rigid porous medium, which makes it possible to directly compare analytical or numerical models to laboratory experiments of packed grains [14,15].…”

Section: Introductionmentioning

confidence: 99%

Gas-induced fluidization of mobile liquid-saturated grains

Ramos¹,

Varas²,

Géminard³

et al. 2015

Phys. Rev. E

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Gas invasion in liquid-saturated sands exhibits different morphologies and dynamics. For mobile beds, the repeated rise of gas through the layer leads to the growth of a fluidized zone, which reaches a stationary shape. Here, we present experimental results characterizing the evolution of the fluidized region as a function of the gas-flow rate and grain size. We introduce a new observable, the flow density, which quantifies the motion of the grains in the system. The growth of the fluidized zone is characterized by a spatiotemporal analysis, which provides the stabilization time, τ(s). In the stationary regime, we report two main contributions to motion in the fluidized region: the central gas rise and a convective granular motion. Interestingly, a static model with a fixed porous network accounts for the final shape of the invasion zone. We propose an explanation where the initial gas invasion weakens the system and fixes since the early stage the morphology of the fluidized zone.

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Section: Introductionmentioning

confidence: 99%

Gas-induced fluidization of mobile liquid-saturated grains

Ramos¹,

Varas²,

Géminard³

et al. 2015

Phys. Rev. E

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“…They found that when the flow regime changed from trickle flow to pulse flow, the pressure drop hysteresis disappeared. Besides pressure measurements, other indirect methods including acoustic detection, conductance technique, capacitance tomography, electrical resistance tomography (ERT), X‐ray radiography, magnetic resonance imaging (MRI), and γ ‐ray tomography were also used to investigate the flow regime transition. Among them, the tomographic methods are helpful for visualizing the macroscopic gas–liquid distribution in the cross section of 3D trickle‐bed reactors, which have been used to reveal the formation mechanism of the pulse flow.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Anadon et al indicated that the trickle‐to‐pulse transition was initiated by isolated local pulsing events, and defined the liquid velocity at which N max (the maximum number of local pulse regions) occurred as the transition point by MRI in 3D trickle beds. Subsequently, Zhao et al found that the liquid blockage between particles was the primary reason for local pulsing events by ERT.…”

Section: Introductionmentioning

confidence: 99%

On flow regime transition in trickle bed: Development of a novel deep‐learning‐assisted image analysis method

Wang

Yang

et al. 2019

AIChE Journal

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An image analysis method was developed based on deep-learning algorithms to extract phase fractions quantitatively in a rectangular trickle bed, and the average identification error was lower than 5%. Furthermore, the flow regime transition in the trickle bed was studied. In trickle-to-pulse flow transition, the trickle flow could be further classified into the stable trickle flow and accelerated one. The SD of liquid fractions and the peak width at half-height of the probability density curve of liquid fractions were close to zero in stable trickle flow, increased rapidly in accelerated trickle flow, and remained approximately constant in pulse flow. In bubble-to-pulse flow transition, dispersed bubbles in bubble flow induced the outliers outside the upper boundary of the boxplot of gas fraction, while alternative appearance of gasrich zone and liquid-rich zone in pulse flow induced outliers outside both the upper and lower boundaries of the boxplot of gas fraction.

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“…As a non-intrusive on-line imaging methods of the particles distribution in particles-liquid two-phase fields, electrical tomography technique [7]- [9] is rather attractive to the industrial applications due to its high temporal resolution, low cost and less complexity [10]. Electrical impedance tomography (EIT) or electrical resistance tomography (ERT) is provided for particles distribution imaging in an electrically conductive medium [11].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Imaging of Particles Distribution in Centrifugal Particles-Liquid Two-Phase Fields by Wireless Electrical Resistance Tomography (WERT) System

et al. 2019

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A wireless electrical resistance tomography (WERT) system has been developed for the realtime imaging particles distribution in centrifugal particles-liquid two-phase fields. The developed WERT system consists of 1) a constant-current injector; 2) a voltage measurement device; 3) two electrodes switching devices; 4) a wireless transmission device; 5) a microcomputer, and: 6) a host computer. The WERT system provides the advantages of miniaturization and wireless transmission as compared to the conventional wired electrical resistance tomography (ERT) systems. Consequently, we wirelessly imaged the real-time particles distribution in the lab-scale centrifuge in particles-liquid (glass beads-NaCl solution) two-phase flow qualitatively at various measurement positions under various rotational velocities. Based on the images, the particles volume fractions in the centrifugal field are measured quantitatively. The measured particles volume fractions at various measurement positions indicate parabolic separation interfaces between the particles-liquid phases, which are in good agreement with the numerical simulation by Euler-Euler method by an average deviation of 7.21%. As the rotational velocity is increased, particles are pushed outward to be raised along the lab-scale centrifuge because of the increased centrifugal force, which causes a sharper paraboloid interface. INDEX TERMS Real-time measurement, particles distribution, centrifuges, wireless electrical resistance tomography.

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Investigation of pulsing flow regime transition and pulse characteristics in trickle-bed reactor by electrical resistance tomography

Cited by 22 publications

References 31 publications

Gas-induced fluidization of mobile liquid-saturated grains

Gas-induced fluidization of mobile liquid-saturated grains

On flow regime transition in trickle bed: Development of a novel deep‐learning‐assisted image analysis method

Real-Time Imaging of Particles Distribution in Centrifugal Particles-Liquid Two-Phase Fields by Wireless Electrical Resistance Tomography (WERT) System

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