本研究探討恆壓微過濾之操作條件，例如過濾壓力、粒子粒徑、流體黏度等，對過濾特性，如過濾通量、濾餅孔隙度與過濾比阻的影響。實驗中以平均孔徑0.1 μm的醋酸纖維薄膜來過濾粒徑0.4 μm與5 μm以不同比例混合之聚甲基丙烯酸甲酯粒子。當過濾壓力提升時，粒子容易被流體帶往膜面形成較為緊密的堆積，濾餅平均孔隙度會下降而平均過濾比阻會上升。當濾餅厚度增加，濾餅表面附近的壓縮壓力會減小，局部孔隙度則會增加。若小粒子所佔比例越高，則平均過濾比阻越高，最小濾餅平均孔隙度發生在大粒子佔75wt%小粒子佔25wt%之比例時。若流體之黏度自1 cp增加為5 cp與10 cp，則濾餅平均孔隙度分別上升了11.92%與18.33%，平均過濾比阻則分別下降12.17%與29.38%，故流體黏度會對過濾特性造成頗為可觀的影響，但對於濾餅之壓縮係數則可以忽略。 The effects of filtration pressure, particle diameter and fluid viscosity on the filtration flux, cake porosity and average specific cake filtration resistance in dead-end constant pressure microfiltration are studied. A filter membrane made of mixed cellulose ester with a mean pore size of 0.1 μm is used for filtering 0.4 μm and 5 μm particle mixtures with different mixing ratios. An increase in filtration pressure leads to a lower average cake porosity and higher specific cake filtration resistance due to larger fluid drag acting on the particle surfaces. Since lower local solid compressive pressure exists in the region near the surface of a thicker cake, the local cake porosity becomes lower. The average specific filtration resistance increases with increasing the mixing ratio of finer particles. However, the lowest cake porosity occurs for a 0.75 coarser particle mixing ratio. When fluid viscosity increases from 1 cp to 5 and 10 cp, the cake porosity increases 11.92% and 18.33%, respectively, while the average specific filtration resistance decreases 12.17% and 29.38%, respectively. In conclusion, fluid viscosity plays a major role on the filtration performance; however, its effect on the cake compressibility can be ignored.
