Entrainment from sieve trays in the froth regime

Kister, Henry Z.; Haas, Joe R.

doi:10.1021/ie00084a018

Cited by 33 publications

(70 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However considerable discrepancies exit between sets of correlations encountered in the literature which makes optimisation of column design difficult to achieve. Experimental works have been carried out on hydrodynamics and mass transfer mainly on sieve trays, and little on valve trays (sieve trays: Zuiderweg and Harmens, 1958;Mc Allister et al, 1958;Barker and Self, 1962;Kister and Haas, 1988;Colwell, 1981;Zuiderweg, 1982;Bennett et al, 1983;Fasesan, 1987;valve trays: Scheffe, 1984;Pohorecki and Moniuk, 1988;Peytavy et al, 1990;Liang et al, 2008). Yet malfunctions on industrial columns still occur (Kister, 2003;Kister and Olsson, 2011), even for sieve trays which have been most studied.…”

Section: Introductionmentioning

confidence: 99%

Effect of path length on valve tray columns: Experimental study

Brahem

Royon-Lebeaud

Legendre

2015

Chemical Engineering Science

View full text Add to dashboard Cite

Hydrodynamic and interfacial area measurements on two different size columns. Phenomenological correlations proposed for key design parameters. A non-negligible effect of the flow path length on mean emulsion profiles. a b s t r a c tExperimental measurements of hydrodynamic and interfacial area parameters are carried out over two rectangular pilot scale valve tray columns. The effect of tray path length on extrapolation between the two columns is studied and phenomenological correlations for hydrodynamic and interfacial area are proposed. Correlations are compared both to literature and to industrial results showing good agreement and a significant improvement for the prediction of industrial conditions. Discrepancies preventing an accurate description of industrial trends are highlighted through comparison between typical emulsion height profiles on both columns.

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of path length on valve tray columns: Experimental study

Brahem

Royon-Lebeaud

Legendre

2015

Chemical Engineering Science

View full text Add to dashboard Cite

show abstract

“…6 , where C n is the ratio of the average bubble diameter (d c ) to the maximum bubble diameter (d max ), and We crit is the critical Weber number, representing the point at which cohesive and disruptive forces become balanced under a maximum stable bubble size (d max ). 23 The C n and We crit values usually behave as constants or small deviations, as demonstrated in most studies regarding a steady flow system.…”

Section: Resultsmentioning

confidence: 99%

Prediction of gas–liquid interfacial area in valve trays

Wang¹,

Leng²,

Shao³

et al. 2015

AIChE Journal

View full text Add to dashboard Cite

An accurate prediction of gas-liquid interfacial area is very important for the design and optimization of column trays. However, the difference of the gas-liquid flow regimes operating at different scale trays significantly affect the interfacial area calculation. Therefore, in this study, an interfacial area model operating at small column was established using the Kolmogorov's isotropic turbulence hypothesis. According to the analyzes of the gas-liquid flow phenomena of different scale columns, an assumption that the similarity principle of flow characteristics of gas-liquid in full contact was proposed. Moreover, a new model that can be used to predict the gas-liquid interfacial area of a large column with exiting the nonideal flow was obtained through the extension of the small tray interfacial area model based on this principle. Finally, the new model was tested by comparisons with the experimental results of references. The prediction accuracy significantly improved with the maximum deviation of approximately 40%. V C 2015 American Institute of Chemical Engineers AIChE J, 62: 905-915, 2016 Keywords: distillation, different scales, valve tray, interfacial area, physical model IntroductionDistillation is the major process in present and future petroleum and/or chemical industries.1 Heat and mass transfers between gas and liquid phases occur in trays during distillation. Briefly, these transfer processes occur via phase interface. Hence, the interfacial area is an important field of investigation in chemical engineering research. Generally, studies on the interfacial area have mainly focused on two aspects: (1) increasing the contact interfacial area of the gasliquid interface by some means or the optimization of equipment structures to enhance the mass and heat transfer processes and (2) developing gas-liquid interfacial area models to predict the transfer of mass or heat. Valve trays grafted with some special structures are widely used as contactors for distillation/absorption columns because of their high tray efficiency, relatively low pressure drop, and large operation range (enhanced performance).2 However, previous research on hydrodynamics and mass transfer has mainly focused on sieve trays, [3][4][5][6][7][8][9][10] and little attention has been centered on valve trays.11-15 Therefore, high-accuracy models should be developed on the basis of theoretical research regarding the actual flow characteristics of gas-liquid in valve trays to calculate the hydraulic and mass transfer rates. These models will provide theoretical guidance for the reasonable design and optimization of trays.Column diameter and height are two main parameters involved in industrial column design. The column diameter is controlled by two-phase flow hydrodynamic behavior (weeping or flooding), whereas the total column height is controlled by mass transfer parameters. 15 To date, the actual trays of a column (cf. column height) are determined by two main methods: (1) tray efficiency based on equilibrium stage model [16][17][18] an...

show abstract

“…In the USA, at least 40 000 distillation columns represent an invested capital of roughly 8 billion $ covering approximately 90 -95 % of all separation processes [1]. Predicting entrainment on a reliable basis has many benefits such as reduction of investment costs by prevention of overdesign [2,6] or reduction of operation costs by increasing efficiency [7]. The phase slip or entrainment is a transport of the liquid phase droplets by the gaseous flow from one tray to the next tray above causing back-mixing leading to a reduction of the driving force and by association lower efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, an increase of entrainment with rising gaseous flow rates is clearly identified [3, 4, 8 -11] and the effect of liquid flow rates on entrainment is ambiguous [3,12]. For instance, an increase of entrainment with rising gaseous flow rates is clearly identified [3, 4, 8 -11] and the effect of liquid flow rates on entrainment is ambiguous [3,12].…”

Section: Introductionmentioning

confidence: 99%

Quantification of Entrainment Using an Optical Inline Probe

Lichti

Schulz

Bart

2019

Chemie Ingenieur Technik

View full text Add to dashboard Cite

In distillation and absorption processes, entrainment above trays or packings reduces stage and column efficiency. A modified version of the optical multimode online probe enables a seminal insight and, thus, quantification of entrained droplets on various axial and radial positions. A purging mechanism inhibits precipitation of droplets on the front lenses, while telecentric optics and illumination provide distance-independent and precise imaging of entrained droplets between two valve trays. Experiments were performed in a DN 450 cold flow (air-water) test rig. The results were compared with noninvasive phase Doppler anemometry data.

show abstract

Entrainment from sieve trays in the froth regime

Cited by 33 publications

References 7 publications

Effect of path length on valve tray columns: Experimental study

Effect of path length on valve tray columns: Experimental study

Prediction of gas–liquid interfacial area in valve trays

Quantification of Entrainment Using an Optical Inline Probe

Contact Info

Product

Resources

About