Filtration of an isotonic suspension of baker's yeast through a 0.45-μm membrane was studied at two different pressures, 40 and 80 kPa, for yeast concentrations ranging from 0.14 to 51 kg/m3 (dry weight). For a yeast volume fraction above 0.06 (∼21.8 kg/m3), the porosity of the yeast cake is less dependent on the suspension concentration. For highly diluted suspensions, the specific cake resistance approaches a minimum that depends on the filtration pressure. Correlation functions of cake porosity and specific cake resistance were obtained for the concentration range investigated showing that the Kozeny–Carman coefficient increases when the applied pressure increases. Both filtration pressure and slurry concentration can be process controlled. In the range of moderate yeast concentration, the filtrate flux may be increased by manipulating the filtration pressure and the slurry concentration, thereby improving the overall process efficiency. The complex behavior of yeast cakes at high slurry concentration can be described by a conventional model as long as part of yeast cells are assumed to form aggregates, which behave as single bigger particles. The aggregation effect may be accounted for using a binary mixture model.
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机译：在40和80 kPa的两个不同压力下，研究了通过0.45-μm膜过滤面包酵母等渗悬浮液的过程，酵母浓度范围为0.14至51 kg / m3（干重）。对于高于0.06（〜21.8 kg / m3）的酵母体积分数，酵母饼的孔隙度较少取决于悬浮液浓度。对于高度稀释的悬浮液，比滤饼的阻力接近最小值，这取决于过滤压力。在所研究的浓度范围内，获得了滤饼孔隙率与比滤饼阻力的相关函数，表明当施加压力增加时，Kozeny-Carman系数增加。过滤压力和浆液浓度均可进行过程控制。在中等酵母浓度的范围内，可以通过控制过滤压力和浆液浓度来增加滤液通量，从而提高整体工艺效率。只要假定一部分酵母细胞形成聚集体（表现为单个较大颗粒），就可以通过常规模型描述高浆液浓度下酵母饼的复杂行为。可以使用二元混合模型解释聚集效应。
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