Bruce L J, Ghose S, Chase H A
Department of Chemical Engineering, University of Cambridge, UK.
Bioseparation. 1999;8(1-5):69-75.
The effect of column verticality on liquid dispersion and separation efficiency in expanded bed adsorption columns was investigated using 1 and 5 cm diameter columns. Column misalignment of only 0.15 degree resulted in the reduction of the Bodenstein number from 140 to 50 for the 1 cm dia. column and from 75 to 45 for the 5 cm dia. column. This degree of misalignment was not detectable by visual assessment of adsorbent particle movement within the column. Depending on the relative importance of transport limitations, kinetic limitations and dispersion to any specific separation, this increase in dispersion with column alignment can significantly affect separation efficiency. Pure protein breakthrough profiles resulting from the application of bovine serum albumin onto STREAMLINE Q XL demonstrated that, at 10% breakthrough, 7.8% more protein could be applied to a vertical 1 cm dia. column compared to the same column misaligned by 0.15 degree. When an unclarified yeast homogenate was applied to a 1 cm dia. vertical column packed with STREAMLINE DEAE, 10% breakthrough of glucose-6-phosphate dehydrogenase (G6PDH) corresponded to a load 55% greater compared to the same column aligned 0.185 degree off-vertical. The G6PDH breakthrough curves for vertical and 0.15 degree off-vertical runs performed using a 5 cm column were essentially indistinguishable.
使用直径为1厘米和5厘米的柱体，研究了柱体垂直度对膨胀床吸附柱中液体分散和分离效率的影响。对于直径1厘米的柱体，仅0.15度的柱体未对准就导致博登斯坦数从140降至50；对于直径5厘米的柱体，该数值从75降至45。通过目视评估柱体内吸附剂颗粒的移动，无法检测到这种未对准程度。根据传输限制、动力学限制和分散对任何特定分离的相对重要性，柱体未对准导致的分散增加会显著影响分离效率。将牛血清白蛋白应用于STREAMLINE Q XL上得到的纯蛋白突破曲线表明，在10%突破时，与未对准0.15度的同一柱体相比，垂直的直径1厘米柱体可多应用7.8%的蛋白。当将未澄清的酵母匀浆应用于填充有STREAMLINE DEAE的直径1厘米垂直柱体时，葡萄糖-6-磷酸脱氢酶（G6PDH）10%突破时的负载量比未对准0.185度的同一柱体高55%。使用5厘米柱体进行的垂直和偏离垂直0.15度运行的G6PDH突破曲线基本无法区分。
