Karau A, Benken C, Thömmes J, Kula M R
Institute of Enzymetechnology, Heinrich-Heine University Düsseldorf, P.O. Box 2050, 52404 Jülich, Germany.
Biotechnol Bioeng. 1997 Jul 5;55(1):54-64. doi: 10.1002/(SICI)1097-0290(19970705)55:1<54::AID-BIT7>3.0.CO;2-W.
The influence of matrix properties and operating conditions on the performance in fluidized-bed adsorption has been studied using Streamline diethyl-aminoethyl (DEAE), an ion exchange matrix based on quartz-weighted agarose, and bovine serum albumin (BSA) as a model protein. Three different particle size fractions (120-160 microm, 120-300 microm, and 250-300 microm) were investigated. Dispersion in the liquid phase was reduced when particles with a wide size distribution were fluidized compared to narrow particle size distributions. When the mean particle diameter was reduced, the breakthrough capacities during frontal adsorption were enlarged due to a shorter diffusion path length within the matrix. At small particle diameters the effect of film mass transfer became more relevant to the adsorption performance in comparison to larger particles. Therefore matrices designed for fluidized-bed adsorption should have small particle diameter and increased mean particle density to ensure small diffusion path length in the particle and a high interstitial velocity to improve film mass transfer. Studies on the influence of sedimented matrix height on axial mixing showed an increased Bodenstein number with increasing bed length. Higher breakthrough capacities were also found for longer adsorbent beds due to reduced dispersion and improved fluid and particle side mass transfer. With increasing bed height the influence of flow rate on breakthrough capacity was reduced. For a settled bed height of 50 cm breakthrough capacities of 80% of the equilibrium capacity for flow rates varying from 3 to 9 cm/min could be achieved.
使用基于石英加权琼脂糖的离子交换基质Streamline二乙氨基乙基（DEAE）和牛血清白蛋白（BSA）作为模型蛋白，研究了基质特性和操作条件对流化床吸附性能的影响。研究了三种不同的粒径级分（120 - 160微米、120 - 300微米和250 - 300微米）。与窄粒径分布相比，宽粒径分布的颗粒流化时，液相中的分散度降低。当平均粒径减小时，由于基质内扩散路径长度缩短，前沿吸附过程中的穿透容量增大。与较大颗粒相比，在小粒径时，膜传质对吸附性能的影响更为显著。因此，为流化床吸附设计的基质应具有小粒径和增加的平均颗粒密度，以确保颗粒内的扩散路径长度短，并具有高间隙速度以改善膜传质。关于沉降基质高度对轴向混合影响的研究表明，随着床层长度增加，博登斯坦数增加。由于分散度降低以及流体和颗粒侧传质改善，较长的吸附剂床层也具有更高的穿透容量。随着床层高度增加，流速对穿透容量的影响减小。对于50厘米的沉降床层高度，流速在3至9厘米/分钟之间变化时，可实现平衡容量80%的穿透容量。
