Experimental Studies of Liquid Weeping and Bubbling Phenomena at Submerged Orifices

Peng, Wildon L.; Yang, Guoqiang; Fan, Liang‐Shih

doi:10.1021/ie0106581

Cited by 9 publications

(14 citation statements)

References 9 publications

(20 reference statements)

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“…Factors such as superficial orifice gas velocity, liquid physical properties, operating pressure, plenum volume, orifice diameter and thickness, orifice taperness, orifice number, and pitch distance on the gas distributor plate that affect liquid weeping have been extensively studied. [1][2][3][4][5][6][7][8][9][10] However, the effect of orifice surface roughness on liquid weeping in bubble columns is not available in the literature, though surface roughness has already been found to affect numerous scientific and engineering applications. [11][12][13][14][15][16][17][18][19][20] It has been reported in our previous study that a bubble and liquid weeping cycle can be classified into four stages: bubbling, gas-liquid interface movement, weeping, and bridging.…”

Section: Introductionmentioning

confidence: 99%

Effect of Orifice Surface Roughness on the Liquid Weeping in Bubble Columns

Hossain

Pang

et al. 2010

Ind. Eng. Chem. Res.

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Liquid weeping at the orifices of a gas distributor plate is one problem commonly encountered in bubble column operations. The effect of orifice surface roughness on the liquid weeping phenomenon in a bubble column is investigated over a superficial orifice gas velocity range of 143−703 cm/s. High-speed images of the bubbling and liquid weeping process are analyzed using a computer-aided image analysis algorithm. Pressure fluctuation in the plenum is also monitored. The liquid weeping rate is found to decrease with an increase in orifice surface roughness at low superficial orifice gas velocities while it increases with an increase in surface roughness at high superficial orifice gas velocities. Analysis indicates that the orifice surface roughness affects liquid weeping indirectly by changing the bubbling behaviors at the orifice. At low superficial orifice gas velocities, an increase in orifice surface roughness reduces the bubble size at bubble detachment. The reduction in pressure fluctuation in the plenum thus decreases the liquid weeping rate. On the other hand, as the superficial orifice gas velocity is approaching the bubbling/jetting regime transition, an increase in orifice surface roughness increases the transition velocity and hence the liquid weeping rate increases. Nonetheless, a modification of the orifice surface roughness is a viable solution to the liquid weeping problem in industrial bubble columns.

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Section: Introductionmentioning

confidence: 99%

Effect of Orifice Surface Roughness on the Liquid Weeping in Bubble Columns

Hossain

Pang

et al. 2010

Ind. Eng. Chem. Res.

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“…[1][2][3] However, one of the common problems in the operation of bubble column reactors is the weeping of liquid at the gas distributor plate. [4][5][6][7][8][9][10] Upon the detachment of the bubbles from the gas distributor plate, liquid flows from the column section through the orifices of the gas distributor plate into the plenum for a short period of time. This phenomenon of liquid flowing from the column section into the plenum is called "liquid weeping".…”

Section: Introductionmentioning

confidence: 99%

“…4,7 Depending on the plenum volume and superficial orifice gas velocity, doubling, pairing, and jetting may occur at the bubbling stage. 6 There is a sudden decrease in plenum pressure in the bubbling stage.…”

Section: Introductionmentioning

confidence: 99%

“…The liquid weeping rate decreases as the plenum volume increases, especially for orifices of small diameters. 4,5,7 However, the effect of plenum volume is small when the plenum volume is <2 L. 4 As the plenum volume increases, the frequency (as well as the magnitude) of the pressure fluctuation decreases, which, in turn, reduces the liquid weeping rate. 5 Orifice dimensions such as the diameter and the length have a remarkable effect on the liquid weeping rate.…”

Section: Introductionmentioning

confidence: 99%

“…6 In some studies, no liquid weeping is found if the orifice diameter is <2 mm with a large plenum volume under quiescent water. 4,7,9,10 It is believed that, under these conditions, the surface tension force is dominant for small orifices. The liquid weeping rate is larger for an orifice with larger length but no explanation was given.…”

Section: Introductionmentioning

confidence: 99%

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Study of Liquid Weeping at a Tapered Orifice in a Bubble Column Reactor by a Computer-Aided Image Analysis Algorithm

Hossain

Pang

et al. 2010

Ind. Eng. Chem. Res.

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Understanding the phenomenon of liquid weeping requires knowledge of the bubbling and weeping cycle. Hence, an image analysis algorithm is developed and subsequently coupled with high-speed imaging techniques to examine the different stages in the bubbling and weeping cycle automatically. The bubbling and weeping cycle is studied under various operating conditions, using the developed algorithm, coupled with high-speed imaging techniques and the pressure fluctuation measurement. The effect of orifice angle (where the orifice angle is a measure of the orifice taperness) on the liquid weeping rate is evaluated over a range of superficial orifice gas velocities and justified with the aid of the developed algorithm, coupled with high-speed imaging techniques. A gas distributor plate with negative angle orifices is recommended for improved operation of industrial bubble column reactors over the range of superficial orifice gas velocities considered in this study, because it substantially decreases the liquid weeping rate.

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Technical Aspects of Natural Gas Pyrolysis in Liquid Metal Bubble Column Reactors

Hofberger,

Dietrich,

Krumholz

et al. 2024

Energy Tech

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The pyrolysis of low alkanes (in the following short “pyrolysis”) has already been investigated during the 1960s. However, none of the reactor systems used at the time are capable of continuous operation. Therefore, the Karlsruhe Institute of Technology has intensified the development of the promising liquid metal bubble column technology in recent years, which is capable of continuous operation. Various key aspects have been addressed, such as scale‐up and the pyrolysis of high‐caloric natural gas. Herein, further developments for a pilot scale system have been investigated, which concern increased throughput and long‐term operation capabilities. Careful evaluation of the impact of according measures has been done, which shows that the achieved scale‐up has only negligible effects on the pyrolysis outcome. The effects of the scale‐up on residence times are negligible. The bubble formation behavior depends on the throughput and the characteristics of the orifice. Wall effects are marginal. Fundamental minimization of weeping could not be confirmed. Reactor pre‐chambers in combination with tin collection chambers are recommended for further scale‐up. An increase in the volume flow should be examined. In terms of long‐term operation , head as well as feed pressure control is recommended.

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Experimental Studies of Liquid Weeping and Bubbling Phenomena at Submerged Orifices

Cited by 9 publications

References 9 publications

Effect of Orifice Surface Roughness on the Liquid Weeping in Bubble Columns

Effect of Orifice Surface Roughness on the Liquid Weeping in Bubble Columns

Study of Liquid Weeping at a Tapered Orifice in a Bubble Column Reactor by a Computer-Aided Image Analysis Algorithm

Technical Aspects of Natural Gas Pyrolysis in Liquid Metal Bubble Column Reactors

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