Investigation of hydrodynamic parameters in a novel expanded bed configuration: local axial dispersion characterization and an empirical correlation study

Abstract

-Study of liquid behavior in an expanded bed adsorption (EBA) system is important for understanding, modeling and predicting nanobioproduct/biomolecule adsorption performance in such processes. In this work, in order to analyze the local axial dispersion parameters, simple custom NBG (Nano Biotechnology Group) expanded bed columns with 10 and 26 mm inner diameter were modified by insertion of sampling holes. Based on this configuration, the particles and liquid can be withdrawn directly from various axial positions of the columns. Streamline DEAE particles were used as solid phase in this work. The effects of factors such as liquid velocity, viscosity, settled bed height and column diameter on the hydrodynamic parameters were investigated. Local bed voidages in different axial bed positions were measured by a direct procedure within the column with 26 mm diameter. Increasing trend of voidage with velocity at a certain position of the bed and with bed height at a certain degree of expansion was observed. Residence time distribution (RTD) analysis at various bed points showed approximately uniform hydrodynamic behavior in the column with 10 mm diameter while a decreasing trend of mixing/dispersion along the bed height at a certain degree of expansion was seen in the column with 26 mm diameter. Also lower mixing/dispersion occured in the smaller diameter column. Finally, a combination of two empirical correlations proposed by Richardson-Zaki and Tong-Sun was successfully employed for identification of the bed voidage at various bed heights (RSSE=99.9%). Among the empirical correlations presented in the literatures for variation of the axial dispersion coefficient, the Yun correlation gave good agreement with our experimental data (RSSE=87%) in this column.

Predicting the Bed Height in Expanded Bed Adsorption Column using R-Z Correlation

“…This correlation has been widely applied for liquid-solid fluidized beds in numerous empirical and semi-empirical studies of average bed expansion. The R-Z correlation was used to measure the average porosity for EBA column [7] and others employed this correlation to measure local bed voidage along the bed height in their classical fluidized bed models [8], [9]. 1where u t is the particle terminal velocity and n is the bed expansion index (R-Z correlation exponent) and n values are shown Table 1 [10].…”

Recovery and purification of recombinant 503 antigen of Leishmania infantum chagasi using expanded bed adsorption chromatography

“…To minimize such limitations, expanded bed adsorption (EBA) has emerged as an innovative and special chromatography technique for the recovery, separation and purification of target biomolecules directly from complex unclarified feedstock without elimination of suspended solids [13,14]. EBA combines the processes of clarification, concentration and initial purification into a one-step operation and thus provides increased process economy, increased yield, shorter overall processing times, reduced work cost, and reduced running costs and capital expenditure [15][16][17].…”