Measurement of gas holdups and sauter mean bubble diameters in bubble column reactors by dynamics gas disengagement method

Daly, James G.; Patel, Snehal A.; Bukur, Dragomir B.

doi:10.1016/0009-2509(92)85081-l

Cited by 74 publications

(50 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This explains the contradictory trends between bubble size and column diameter in the literature [41][42][43]. These contradictory observations are the product of operation within different flow regimes or transitioning between regimes.…”

Section: Column Diametermentioning

confidence: 88%

Characterization of Bubble Size Distributions within a Bubble Column

Mohagheghian

Elbing

2018

Fluids

View full text Add to dashboard Cite

Abstract:The current study experimentally examines bubble size distribution (BSD) within a bubble column and the associated characteristic length scales. Air was injected into a column of water via a single injection tube. The column diameter (63-102 mm), injection tube diameter (0.8-1.6 mm) and superficial gas velocity (1.4-55 mm/s) were varied. Large samples (up to 54,000 bubbles) of bubble sizes measured via 2D imaging were used to produce probability density functions (PDFs). The PDFs were used to identify an alternative length scale termed the most frequent bubble size (d mf ) and defined as the peak in the PDF. This length scale as well as the traditional Sauter mean diameter were used to assess the sensitivity of the BSD to gas injection rate, injector tube diameter, injection tube angle and column diameter. The d mf was relatively insensitive to most variation, which indicates these bubbles are produced by the turbulent wakes. In addition, the current work examines higher order statistics (standard deviation, skewness and kurtosis) and notes that there is evidence in support of using these statistics to quantify the influence of specific parameters on the flow-field as well as a potential indicator of regime transitions.

show abstract

Section: Column Diametermentioning

confidence: 88%

Characterization of Bubble Size Distributions within a Bubble Column

Mohagheghian

Elbing

2018

Fluids

View full text Add to dashboard Cite

show abstract

“…The DGD technique was first used in bubble columns at low gas velocities (U g < 2 cm/s) by Sriram and Mann (1977) to quantify the bubble size and size distribution in the columns. Various models that relate gas disengagement phenomena to bubble size or size distribution have been proposed in the literature (Vermeer and Krishna, 1981;Schumpe and Grund, 1986;Patel et al, 1989;Daly et al, 1992). However, the reliability of the DGD technique applied to the slurry bubble columns operated at high pressure and high gas velocity depends on whether the models account for the transient characteristics of bubble flow during the DGD process.…”

Section: Discussionmentioning

confidence: 99%

Engineering Development of Slurry Bubble Column Reactor (Sbcr) Technology

Toseland¹

2002

View full text Add to dashboard Cite

Project ObjectivesThe major technical objectives of this program are threefold: 1) to develop the design tools and a fundamental understanding of the fluid dynamics of a slurry bubble column reactor to maximize reactor productivity, 2) to develop the mathematical reactor design models and gain an understanding of the hydrodynamic fundamentals under industrially relevant process conditions, and 3) to develop an understanding of the hydrodynamics and their interaction with the chemistries occurring in the bubble column reactor. Successful completion of these objectives will permit more efficient usage of the reactor column and tighter design criteria, increase overall reactor efficiency, and ensure a design that leads to stable reactor behavior when scaling up to large diameter reactors. AbstractThis report summarizes the results of a Department of Energy-funded study on slurry bubble column reactors (SBCR). Alternate fuels projects need high reactor throughput for competitive economics so that reactors must operate in the churn-turbulent region of flow. Little data in this flow regime, especially at the conditions of high pressure and temperature for organic fluids found in an industrial reactor, existed at the inception of this project. This report summarizes the large body of fundamental data that was developed on these flows. It covers both the local liquid turbulence and large-scale liquid internal circulation aspects of flow in the SBCR. Where understood, the underlying mechanisms, which result in the macro-scale phenomena, are elucidated and modeled. Finally, new models for reactor design are also presented. Executive SummaryThe state of the art in design and modeling of bubble columns before the initiation of this project relied solely on the use of ideal flow patterns (e.g., perfectly mixed liquid and plug flow of gas) or on the use of the axial dispersion model (ADM). The use of ideal flow patterns can lead to serious over design, and the uncertainty in the values of the axial dispersion coefficients precludes a more accurate design based on the ADM. Since these models represent crude descriptions of the flow pattern in bubble columns and do not account for input from the fluid dynamics of the system, the scaleup of SCBR has been uncertain.The need for rapid scaleup and optimal commercialization for gas conversion processes necessitated an improved understanding and quantification of fluid dynamics and transport in slurry bubble column reactors. This report presents the results of an extensive experimental and theoretical program on SBCR.This program was conducted by a team comprising Air Products (APCI), Washington University in St. Louis (WU), The Ohio State University (OSU), Iowa State University (ISU) and Sandia National Laboratory (SNL). SNL participated as an active team member, but was supported by separate DOE funds; therefore, SNL's work will not be reported here.Bubble columns are complex. The complexity can be simplified in breaking up the phenomena occurring in bubble columns according to sc...

show abstract

“…The decrease in gas holdup between ti-1 and ti is due to the escape of the bubbles smaller than dB,i. Therefore, the rise velocity (&i) and holdup of bubbles of size dg, j ( E~J ) can be determined by the following equations (Daly et al, 1992):…”

Section: Dynamic Gas Disengqement @Ea Sollapse) Techniquementioning

confidence: 99%

Engineering development of slurry bubble column reactor (SBCR) technology. Quarterly report, April 1--June 30, 1997

Toseland¹

1997

View full text Add to dashboard Cite

Measurement of gas holdups and sauter mean bubble diameters in bubble column reactors by dynamics gas disengagement method

Cited by 74 publications

References 7 publications

Characterization of Bubble Size Distributions within a Bubble Column

Characterization of Bubble Size Distributions within a Bubble Column

Engineering Development of Slurry Bubble Column Reactor (Sbcr) Technology

Engineering development of slurry bubble column reactor (SBCR) technology. Quarterly report, April 1--June 30, 1997

Contact Info

Product

Resources

About