Experimental study of liquid spreading in structured packings

Optimization of industrial gas-liquid columns dedicated to CO2 capture requires prediction of liquid distribution within packed beds. In this context, liquid hold-up as well as liquid spreading from a source point have been investigated for Mellapak 250.X structured packing. Local liquid hold-up measurements have been achieved in a 400 mm diameter column by means of gamma-ray tomography with operation in the counter-current mode at different positions downstream the source point injection. Liquid hold-up and retention map measurements have been performed for two fluid systems: Air / Water and Air / MEA 30wt.%. A correlation that relates global liquid hold-up and liquid load taking into account liquid viscosity is proposed. This correlation has been further used to determine spread factors using a simple dispersion model for all investigated operational conditions. Liquid dispersion model is found to well reproduce experimental data in the range of operational conditions that were tested which enables to determine spread factors for various operating conditions. The spread factor is observed not to vary with liquid load, gas capacity factor in the range of 20% to 80% of flooding nor liquid viscosity. This led us to stipulate that liquid dispersion is controlled by packing geometry only. Nevertheless, the effect of surface tension on liquid hold-up and dispersion is discussed since its effect is not fully understood and calls for further experiments if one wants to apply those results for hydrocarbons.

[1]  R. Billet,et al.  Modelling of pressure drop in packed columns , 1991 .

[2]  Z. Cihla,et al.  Studies of the behaviour of liquids when freely trickling over the packing of a cylindrical tower. II. , 1958 .

[3]  Ludovic Raynal,et al.  Liquid distribution and liquid hold-up in modern high capacity packings , 2008 .

[4]  Ludovic Raynal,et al.  Influence of the viscosity on the liquid hold-up in trickle-bed reactors with structured packings , 2005 .

[5]  F. J. Zuiderweg,et al.  Radial liquid spread and maldistribution in packed columns under different wetting conditions , 1978 .

[6]  F. J. Zuiderweg,et al.  Small scale and large scale liquid maldistribution in packed columns , 1986 .

[7]  Faïçal Larachi,et al.  Mechanistic Model for Structured-Packing-Containing Columns: Irrigated Pressure Drop, Liquid Holdup, and Packing Fractional Wetted Area , 2001 .

[8]  Dieter Mewes,et al.  Modelling of two-phase flow in packings and monoliths , 1999 .

[9]  Z. Olujic,et al.  EXPERIMENTAL CHARACTERISATION AND CFD SIMULATION OF GAS DISTRIBUTION PERFORMANCE OF LIQUID ( RE ) DISTRIBUTORS AND COLLECTORS IN PACKED COLUMNS , 2002 .

[10]  James R. Fair,et al.  General model for prediction of pressure drop and capacity of countercurrent gas/liquid packed columns , 1989 .

[11]  Ž. Olujić,et al.  Experimental characterization and computational fluid dynamics simulation of gas distribution performance of liquid (re)distributors and collectors in packed columns , 2003 .

[12]  E. Ruckenstein,et al.  Liquid distribution in packed columns , 1968 .

[13]  Adrien Gomez,et al.  From MEA to demixing solvents and future steps, a roadmap for lowering the cost of post-combustion carbon capture , 2011 .

[14]  Dominique Legendre,et al.  Mass transfer and liquid hold-up determination in structured packing by CFD , 2012 .

[15]  Hiroshi Takeuchi,et al.  Liquid distribution in a packed column , 1973 .

[16]  Ville Alopaeus,et al.  CFD modeling of radial spreading of flow in trickle-bed reactors due to mechanical and capillary dispersion , 2009 .

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

[18]  Chih-Hao Hsu,et al.  Densities of Aqueous Blended Amines , 1997 .

[19]  L. Spiegel,et al.  Hold-up of mellapak structured packings , 1992 .

[20]  Carsten Stemich,et al.  Characterization and quantification of the quality of gas flow distributions , 2011 .

[21]  Dominique Toye,et al.  Imaging of liquid distribution in reactive distillation packings with a new high-energy x-ray tomograph , 2005 .

[22]  D. Edwards,et al.  Development of an improved method to quantify maldistribution and its effect on structured packing column performance , 1999 .

[23]  Ludovic Raynal,et al.  A multi-scale approach for CFD calculations of gas–liquid flow within large size column equipped with structured packing , 2007 .

[24]  Ž. Olujić,et al.  Liquid Distribution Properties of Conventional and High Capacity Structured Packings , 2006 .