Gupta B Sen, Hasan S, Hashim M A, Cui Z F
School of Chemical Engineering, Queen's University Belfast, BT9 5AG, Northern Ireland, UK.
Department of Nuclear Engineering, University of Missouri-Columbia, Columbia,.
Bioprocess Biosyst Eng. 2005 Oct;27(6):407-413. doi: 10.1007/s00449-005-0012-5. Epub 2005 Nov 3.
Cross-flow microfiltration is an important step in separating Baker's yeast (Saccharomyces cerevisiae) from aqueous suspension in many processes. However the permeate flux often declines rapidly due to colloidal fouling of membranes and concentration polarisation. The present work explores the possibility of maintaining acceptable permeate flux by co-current sparging of gas along with the feed, which would scour away colloidal deposits and reduce concentration polarisation of membranes. In this work, both washed and unwashed yeast were used to study the effect of washing to reduce protein fouling of membranes. It was found that permeate flux increased by 45% for liquid throughput of 75 kg/h for a feed concentration of 2.0 kg/m3 of washed yeast as compared with unwashed yeast suspension without gas sparging. For washed yeast suspension, the increase in gas flow rate from 0.5 lpm to 1.5 lpm (30 l/h to 90 l/h) had beneficial effect on permeate flux. It is concluded that in the present case, the gas flow rate should be less than or equal to the liquid flow rate for enhancement of permeates flux.
错流微滤是许多工艺中从水悬浮液中分离面包酵母（酿酒酵母）的重要步骤。然而，由于膜的胶体污染和浓差极化，渗透通量常常会迅速下降。目前的工作探索了通过与进料并流鼓泡气体来维持可接受的渗透通量的可能性，这将冲刷掉胶体沉积物并减少膜的浓差极化。在这项工作中，使用洗涤过的酵母和未洗涤的酵母来研究洗涤对减少膜蛋白质污染的影响。结果发现，对于进料浓度为2.0 kg/m³的洗涤酵母，在液体通量为75 kg/h时，与未鼓泡气体的未洗涤酵母悬浮液相比，渗透通量提高了45%。对于洗涤过的酵母悬浮液，气体流速从0.5 lpm增加到1.5 lpm（30 l/h到90 l/h）对渗透通量有有益影响。得出的结论是，在当前情况下，为提高渗透通量，气体流速应小于或等于液体流速。
