Eddy diffusivity for distillation sieve trays

Bennett, Douglas L.; Grimm, Henry J.

doi:10.1002/aic.690370412

Cited by 28 publications

(19 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The work of Katayama and Imoto (1972) suggests that for most of the data the vapor is unmixed. To estimate the liquid back-mixing within the bi-phase, we used the correlation for eddy dispersion proposed by Bennett and Grimm (1991) multiplied by four. Since they were only interested in the liquid mixing caused by vapor flowing through the tray, Bennett and Grimm used eddy dispersion data taken only with rectangular trays.…”

Section: Methods To Calculate the Point Eficiencymentioning

confidence: 99%

See 1 more Smart Citation

New correlation for sieve‐tray point efficiency, entrainmnt, and section efficiency

1997

Self Cite

View full text Add to dashboard Cite

A comprehensive composite database for distillation sieve-tray eficiency is used to develop point eficiency and entrainment correlations based on a model that considers the fluid on the distillation tray to be contained in a liquid-continuom region near the tray deck and a vapor-continuous region on top of the liquid-continuous region. This model allows estimates of the portion of the mass transfer that occurs in each region and the mass-transfer resistance that occurs on the liquid side and vapor side of the interface. For most cases, most of the mass transfer occurs within the liquid-continuous region. The liquid side resistance is often significant.The entrainment correlation is consistent with the work of Bennett et al., which relates entrainment to the ratios of the liquid to vapor density and the froth height to the tray spacing. A simple liquid continuous-only mass-transfer model containing only four empirical parameters correlates the point eficiency data to within 6.4%. Despite a twofold change in vapor Schmidt number, no dependency on vapor Schmidt number is seen. Important dimensionless groupings are the Reynolds number based on the hole velocity, effective froth density, ratio of the liquid inventoiy to the perforation diameter, and fraction of the tray area perforated. Mathematically simple and accurate methods allow the prediction of the section eficiency for trays operating in cross or parallel flow. They address vapor and liquid mixing, entrainment and a criterion to avoid significant degradation of the tray eficiency due to weeping.

show abstract

Section: Methods To Calculate the Point Eficiencymentioning

confidence: 99%

“…We recommend that the liquid eddy diffusivity be determined from the correlation of Bennett and Grimm (1991) for rectangular trays, but multiplied by four to compensate for the inlet maldistribution and tray curvature typical of actual tray design. Therefore v .…”

Section: June 1997mentioning

confidence: 99%

New correlation for sieve‐tray point efficiency, entrainmnt, and section efficiency

1997

Self Cite

View full text Add to dashboard Cite

show abstract

“…Liquid backmixing occurs mainly due to two mechanisms: Turbulence in the liquid continuous region, and motion of Ž liquid droplets in the vapor continuous region Bennett and . Grimm, 1991 .…”

Section: Flow On Distillation Traysmentioning

confidence: 99%

Nonequilibrium cell model for multicomponent (reactive) separation processes

1999

View full text Add to dashboard Cite

“…The net effect, especially as tray diameters increase, is to increase the effective difference in fluid velocity between the center of the tray and the edges. This factor becomes significant for towers over 2 m in diameter (Bennett and Grimm, 1991). Yu et al (1990), for example, present measurements of mean residence time profiles using tracer techniques on single-and double-pass half-trays.…”

Section: Introductionmentioning

confidence: 99%

“…The liquid-phase flow patterns are difficult to idealize. A more realistic evaluation includes an analysis of droplet trajectories, which results in a further complication (Bennett and Grimm, 1991), but clearly is an important factor in backmixing.…”

Section: Introductionmentioning

confidence: 99%

Improving hydraulics and efficiencies with the T‐By sieve tray

Tedder

Bravo

Parker³

et al. 1993

AIChE Journal

View full text Add to dashboard Cite

A modified sieve (that is, T-By) tray uses a system of weirs and risers to approximate liquid plug flow over a cross-flow, circular-section tray. Vapor-liquid contact is improved using a system of curtain-pattern vapor holes and intermediate weirs to form cells across the tray that promote liquid mixing into discrete, wellmixed pools and stabilize froth. A theoretical model is used to analyze experimental data, guide tray design, and suggest new strategies for improving performance. These results indicate that tray efficiencies and stabilities can be increased without capacity losses. Pressure drop can also be manipulated to enhance performance.

show abstract

Eddy diffusivity for distillation sieve trays

Abstract: A n understanding of the eddy diffusivity on a distillation tray is important to

Cited by 28 publications

References 4 publications

New correlation for sieve‐tray point efficiency, entrainmnt, and section efficiency

New correlation for sieve‐tray point efficiency, entrainmnt, and section efficiency

Nonequilibrium cell model for multicomponent (reactive) separation processes

Improving hydraulics and efficiencies with the T‐By sieve tray

Contact Info

Product

Resources

About