Liquid flow texture analysis in trickle bed reactors using high-resolution gamma ray tomography

Trickle bed reactor performance and safety may suffer from radial and axial liquid maldistribution and thus from non-uniform utilization of the catalyst packing. Therefore, experimental analysis and fluid dynamic simulation of liquid–gas flow in trickle bed reactors is an important topic in chemical engineering. In the present study for the first time a truly high-resolution gamma ray tomography technique was applied to the quantitative analysis of the liquid flow texture in a laboratory cold flow trickle bed reactor of 90 mm diameter. The objective of this study was to present the comparative analysis of the liquid flow dynamics for two different initial liquid distributions and two different types of reactor configurations. Thus, the hydrodynamic behavior of a glass bead packing was compared to a porous Al2O3 catalyst particle packing using inlet flow from a commercial spray nozzle (uniform initial liquid distribution) and inlet flow from a central point source (strongly non-uniform initial liquid distribution), respectively. The column was operated in downflow mode at a gas flow rate of 180 L h−1 and at liquid flow rates of 15 and 25 L h−1.

[1]  W. Nicol,et al.  Trickle flow distribution and stability by X-ray radiography , 2007 .

[2]  Uwe Hampel,et al.  Time resolving gamma-tomography for periodically changing gas fraction fields and its application to an axial pump , 2003 .

[3]  F. A. Kulacki,et al.  Design of an Isotopic CT Scanner for Two Phase Flow Measurements , 1980, IEEE Transactions on Nuclear Science.

[4]  Rajamani Krishna,et al.  Strategies for multiphase reactor selection , 1994 .

[5]  Ajit V. Sapre,et al.  Heater probe technique to measure flow maldistribution in large scale trickle bed reactors , 1990 .

[6]  G. Kwant,et al.  Estimation of trickle-to-pulse flow regime transition and pressure drop in high-pressure trickle bed reactors with organic liquids , 2005 .

[7]  P. V. Ravindra,et al.  Liquid Flow Texture in Trickle-Bed Reactors: An Experimental Study , 1997 .

[8]  Sailesh Kumar,et al.  A γ-ray tomographic scanner for imaging voidage distribution in two-phase flow systems , 1995 .

[9]  Robert A. Meyers,et al.  Handbook of Petroleum Refining Processes , 2003 .

[10]  J. Chaouki,et al.  Noninvasive Tomographic and Velocimetric Monitoring of Multiphase Flows , 1997 .

[11]  Timothy J. O'Hern,et al.  Gamma-densitometry tomography of gas holdup spatial distribution in industrial-scale bubble columns , 1995 .

[12]  V. Alopaeus,et al.  A cellular automata model for liquid distribution in trickle bed reactors , 2006 .

[13]  Matthew H. M. Lim,et al.  MRI visualisation of two-phase flow in structured supports and trickle-bed reactors , 2003 .

[14]  Milorad P. Dudukovic,et al.  Opaque Multiphase Reactors: Experimentation, Modeling and Troubleshooting , 2000 .

[15]  G. Herman,et al.  Algebraic reconstruction techniques (ART) for three-dimensional electron microscopy and x-ray photography. , 1970, Journal of theoretical biology.

[16]  U. Parasu Veera,et al.  Gamma ray tomography design for the measurement of hold-up profiles in two-phase bubble columns , 2001 .

[17]  Robert F. Mudde,et al.  Subchannel void-fraction measurements in a 6 × 6 rod bundle using a simple gamma-transmission method , 2001 .

[18]  Ludovic Raynal,et al.  Flow Distribution Studies Applied to Deep Hydro-Desulfurization , 2001 .

[19]  Christophe Boyer,et al.  Measurement of liquid flow distribution in trickle bed reactor of large diameter with a new gamma-ray tomographic system , 2002 .

[20]  Milorad P. Dudukovic,et al.  Study of liquid spreading from a point source in a trickle bed via gamma-ray tomography and CFD simulation , 2005 .

[21]  Uwe Hampel,et al.  Design of a high-resolution gamma-ray detector module for tomography applications , 2007 .

[22]  V. Parmon,et al.  In situ MRI of the structure and function of multiphase catalytic reactors , 2005 .

[23]  K. Nigam,et al.  Enhanced liquid spreading due to porosity , 2004 .

[24]  R. Missen,et al.  Trickle‐bed reactors: Tracer study of liquid holdup and wetting efficiency at high temperature and pressure , 1991 .

[25]  Artin Afacan,et al.  Liquid holdup distribution in packed columns: gamma ray tomography and CFD simulation , 2002 .

[26]  K. Nigam,et al.  Partial wetting in porous catalysts: wettability and wetting efficiency , 2002 .

[27]  Avinash C. Kak,et al.  Principles of computerized tomographic imaging , 2001, Classics in applied mathematics.

[28]  Milorad P. Dudukovic,et al.  Multiphase reactors – revisited , 1999 .

[29]  F. Zimmermann,et al.  High resolution gamma ray tomography scanner for flow measurement and non-destructive testing applications. , 2007, The Review of scientific instruments.

[30]  Artin Afacan,et al.  Porosity distribution in random packed columns by gamma ray tomography , 2001 .

[31]  Anthony J. Peyton,et al.  Chemical engineering applications of electrical process tomography , 2003 .

[32]  Gabriel Wild,et al.  Liquid Distribution in Trickle-Bed Reactor , 2000 .

[33]  J. Schuster,et al.  Evaluation of steady flow profiles in rectangular and circular packed beds by a variational method , 1983 .