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Bioseparations using nonmagnetic supports in magnetically stabilized fluidized beds
Abstract
Liquid-fluidized magnetically stabilized beds (MSFBs) are easy to form but their use in continuous contacting applications is limited largely because of the perceived limitations in bed operation due to the support material. Prior to our work, only magnetically susceptible particles could be used in liquid-fluidized stabilized beds. We have investigated the formation and application of mixed beds, the multiple support magnetically stabilized fluidized beds (MS-MSFBs), containing nonmagnetic supports to adsorb biochemicals and inert magnetic particles to stabilize the bed. The multiple support MSFB offers the advantages of the MSFB without the restriction of having to use adsorbents that are magnetically susceptible. The MS-MSFB combines the advantages of an MSFB and a packed bed. The multiple support MSFB is simple to operate and is able to function with a large number of commercial packings, similar to packed beds. The MS-MSFB properties of continuous countercurrent contact, low pressure drop, large throughput rate, and clog-free operation are more similar to MSFBs. The stability of the bed, defined as the absence of particle movement, was characterized experimentally. Results obtained with nickel and glass beads indicate that more nonmagnetic particles can be trapped at a higher magnetic field strengths and at lower fluidization velocities. Larger nonmagnetic beads as well as denser nonmagnetic supports also lead to a higher volume fraction of nonmagnetic particles trapped. A mathematical model was developed based on the ability of the bed to resist deformation and was used to qualitatively predict the stability of the bed and the volume fraction of nonmagnetic particles that can be stabilized under a given set of operating conditions. This novel unit operation device, the multiple support magnetically stabilized fluidized bed, is then applied to a continuous countercurrent contacting process. The ability of the bed to flow continuously in plug flow countercurrent to the fluid leads to mass transfer efficiency nearly equal to that of a packed bed. We demonstrate the feasibility of this device for protein adsorption, desorption and separation.
Subject Area
Chemical engineering
Recommended Citation
Chetty, Ashok Sevugan, "Bioseparations using nonmagnetic supports in magnetically stabilized fluidized beds" (1990). Doctoral Dissertations Available from Proquest. AAI9110116.
https://scholarworks.umass.edu/dissertations/AAI9110116