Comparative study of hydrodynamic behavior of liquid expanded bed adsorption: mathematical and short-cut methods

Abstract

Liquid fluidized/expanded bed adsorption (LF/EBA) is a novel chromatography technique for capturing target biomolecules directly from crude feedstock in downstream processing. To widely extend the LF/EBA technology in biological industries, a better understanding of the expanded-bed behavior is necessary to maximize its efficient applications. In this study, streamline adsorbent was loaded into the column and the bed was subjected to physical and hydrodynamical experiments. Hydrodynamic characteristics of the bed (e.g., Daxl and Bo) with different settled bed height (SBH=5,6,7,8,9,10,11,12cm) along with a variety of column diameters (1,1.6,2.5 cm) have been investigated based on exact mathematical as well as approximate short-cut methods. It was found that the increasing column diameter promoted bed mixing, which was undesirable, and the optimal values for the bed expansion and SBH based on minimal liquid mixing were 80%-130% and 8-10 cm, respectively. However, exploiting the short-cut method for the bed hydrodynamic assessments also demonstrated results as good as the mathematical method. Hydrodynamic behavior of liquid fluidized bed adsorption and the generic application of the short-cut method and its potential as a simple method for study of hydrodynamic performance is discussed

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

“…The calculated terminal velocities of the above models are sown in Table 4. The predicted/calculated values of the porosity are shown in Figure 5a and 5b respectively along with Literature data [12], [14], [15]. The literature data is in agreement with prediction data.…”

“…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]. [11] can also be used to predict [12] the particle terminal Reynolds number. The correlation was given below (3) where Ar is Archimedes number The terminal velocity calculated using Eq (4) as shown below (4) The above two methods were used to calculate the terminal velocity and substituted in Eq (1) of R-Z equation to calculate the average porosity.…”

Emerging technologies for the integration and intensification of downstream bioprocesses

“…Coupled with an effective and uniform flow distribution system, such as the rotating fluid distributor, this technology is now scalable up to 60 cm (internal diameter) columns (Rhobust™ Flex system) [76]. Additionally, ideal bed expansion factors for optimal product capture have been deter-mined to be within 1.8-2.2-times the sedimented bed height [83], and while changes in mobile phase viscosity (e.g., between buffer and crude feedstock) might lead to bed instability, sensitive ultrasonic detectors have been adapted to the expanded bed systems, which automatically adjust flow rates to maintain ideal bed expansion via a feedback loop [84]. Numerous examples clearly highlight the huge potential contained in the EBA methodology [85][86][87].…”