A fundamental model for valve tray vapor cross‐flow channeling calculation

Wang, Jun; Leng, Yixin; Shao, Hui; Li, Weimin; Xue, Bin; Huang, Chunxiang; Tan, Qian; Yang, Ping; Chen, Tianxing

doi:10.1002/aic.14691

Cited by 6 publications

(17 citation statements)

References 9 publications

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“…However, the two key hydraulic parameters (clear liquid height and liquid holdup) in Eq. 15 and the VCFC model 21 were calculated by empirical correlation. Therefore, the selection of both correlations is very important to calculate the interfacial area.…”

Section: Extension Of the New Interfacial Area Modelmentioning

confidence: 99%

“…Wang et al 21 proposed a model for valve tray VCFC calculation according to the optimization gas-liquid energy of a tray. The proposed VCFC model comprises five main equations, that is, fractional bubbling area equation, dry tray pressure drop equation, liquid height of the weeping area equation, clear liquid height of the bubbling area equation, and liquid holdup equation.…”

Section: Appendix A: a Brief Introduction Of Vcfc Modelmentioning

confidence: 99%

“…These parameters (u 1 , a l , and h cl ) can be calculated by the VCFC model (c.f., Appendix A for more detailed information). 21 The expression form of Eq. 13 is notably similar to the relationship between ideal and nonideal solutions.…”

mentioning

confidence: 99%

“…VCFC) has been proposed using the optimal gas-liquid energy of a tray. 21 The current research is an extension of the In the present study, a semiempirical model to predict the gas-liquid interfacial area of different scale trays was constructed in accordance with the Kolmogorov's isotropic turbulence hypothesis 22 and the similarity principle of the flow characteristics of gas-liquid in full contact, which was obtained by theoretical analysis of the gas-liquid flow characteristics of different scale trays. The new model considered the influence of gas-liquid nonideal flow (cf.…”

mentioning

confidence: 99%

“…Once the high-velocity gas comes into contact with the liquid, their interaction (momentum transfer) will transform the gas kinetic energy into potential energy of the liquid. 21 Subsequently, gravity will transform the liquid potential energy into kinetic energy of the falling liquid. 23 In this process, the rate of work done per unit area can be written as follows…”

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confidence: 99%

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Prediction of gas–liquid interfacial area in valve trays

Wang¹,

Leng²,

Shao³

et al. 2015

AIChE Journal

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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...

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Section: Extension Of the New Interfacial Area Modelmentioning

confidence: 99%

Section: Appendix A: a Brief Introduction Of Vcfc Modelmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Prediction of gas–liquid interfacial area in valve trays

Wang¹,

Leng²,

Shao³

et al. 2015

AIChE Journal

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Experimental study and modeling of weeping rate in rectangular large‐scale valve trays

et al. 2019

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Weeping is an important hydraulic parameter that needs to be considered for valve trays and for calculations in the distillation field. Therefore, the accurate prediction of weep rate is crucial for the optimal design of valve trays. First, the effects of gas and liquid loads and weir height on weep rate, tray pressure drop, and actual bubbling area were studied in a 1.5 m × 0.61 m cold simulator. Second, the weep modes on the valve tray were analyzed in detail. A theoretical model was then derived to calculate weeping. The model showed a clear relationship between the weep rate and the fractional bubbling area. The experimental data showed that the weir height substantially affected the orifice coefficient of the liquid passing through the valve. Finally, the relation between weir height and orifice coefficient was obtained by fitting the experimental data. The agreements were good, and the maximum deviations were approximately 25%.

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Mechanism and fundamental models of gas–liquid surging for valve columns

Liu

Cao

et al. 2021

AIChE Journal

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The gas–liquid streams in valve columns are likely to surge at low gas velocities, which degrades tray performances and threatens production safety. Therefore, the gas–liquid surging mechanism and vibration properties were investigated in this article. First, the theory of gas–liquid unstable flow at the seal point was proposed based on the principle of lowest energy. Then, the evolution mechanism, gas–liquid flow characteristics, and essential condition of surging are proposed. Meanwhile, experiments were carried out in a Φ580 mm valve column; the frequency spectral and hydraulic characteristics of surging were in accordance with the expected surging mechanism. Moreover, the surging vanish point criterion and safe operating superficial gas velocity for valve columns were advanced. Finally, fundamental models for surging frequency and amplitude were established. The models are in close accordance with the experimental data, which suggests that they could accurately describe the surging behavior.

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A fundamental model for valve tray vapor cross‐flow channeling calculation

Cited by 6 publications

References 9 publications

Prediction of gas–liquid interfacial area in valve trays

Prediction of gas–liquid interfacial area in valve trays

Experimental study and modeling of weeping rate in rectangular large‐scale valve trays

Mechanism and fundamental models of gas–liquid surging for valve columns

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