| 摘要: | 超在掃流超過濾器中加快流體速度將產生兩種互相牴觸之效應:其一為減小濃度極化層阻力,此對超過濾有利;另一為對操作不利的透膜壓差下降。超過濾操作中,沿一掃流超過濾器之流體通道內,濃度極化層阻力逐漸增大而透膜壓差反而逐漸下降,因此適當調節沿通道之對流強度,將可同時有效減小濃度極化層阻力及保持相當量的透膜壓差,而提高超過濾效率。沿循此觀念,第一年計畫將涉及「沿插棒型薄模管中改變棒徑以提高超過濾效率」之研究,第二年計畫將探討「沿插捆線棒型薄膜管中改變捆線角度以提高超過濾效率」。由於這些改良型裝置的建立將引起動力消耗的增加,此亦將是本研究討論的範籌內。有了這些改變型裝置之推出及研發將有利超過濾操作之實際應用。 Increasing the fluid velocity in cross-flow membrane ultrafilter has two conflicting effects: one, the decrease in concentration polarization resistance, which in good for ultrafiteration; while the other, the decrease in transmembrane pressure is bad for performance. Along the flow channel of a cross-flow membrane ultrafilter, concentration polarization increases while transmembrane pressure decrease. Therefore, proper adjustment of the convection strength along the flow channel might effectively suppress the undesirable concentration resistance while still preserving the effective transmembrane pressure, and thereby lead to improved permeate recoveries. Along this concept, in first-year study we will deal with the effect of hydraulic behavior on ultrafilteration in a membrane tube inserted concentrically with a solid rod of linearly varied rod-radius. In the second-year study, the effect of hydraulic behavior on ultrafilteration in a membrane tube inserted concentrically with a uniform-radiue solid rod wrapped by a wire spiral with a wire angle varied at a uniform rate along the flow channel, will be investigated. The enlargement of power consumption for fluid flow due to such arrangements will be also discussed. With these arrangements the appropriate manners of velocity variation along the flow channel for improving performance may be obtained. |
