Katsuya Ebara

Vapor Permeate Characteristics of Membrane Distillation

Abstract To study the permeate characteristics of membrane distillation considering heat and mass transfers and concentration polarization, theoretical and experimental studies were performed. To understand the effect of concentration polarization, concentrated solutions of LiBr and H2SO4 were used as feed. The permeate flux was found to be proportional to the vapor pressure difference between the feed and cooled surface and decreased with increasing concentration because of the concentration and temperature polarization. Furthermore, when considering the heat and mass transfers and concentration polarization, the permeate flux could be estimated accurately.

Water Quality Evaluation of the Water Purification System for 16Mbit LSI Production Using Total Solid Monitor.

半導体ウエハの洗浄工程で大量に用いられる高純度超純水の製造装置の性能を評価するため.集積度16Mbit対応超純水の水質を従来指標と新指標である全蒸発残留不純物量 (Ts : Total Solid) で, オンライン計測した.実験に供試した超純水の水質は従来指標では16Mbit対応超純水の目標値を十分満足しているものの.TS値が高いため.さらに装置の高性能化が必要なことが明確になった.水中の主不純物であるTOC (Total Organic Carbon) 値とTS値を用いて、超純水製造プロセス系の要素機器の処理性能を評価した結果, UV酸化, イオン交換, 限外濾過の各プロセスからの不純物の溶出があり, 超純水は原水とは異なり溶出成分 (57%) や難酸化性成分 (50%) が多いと推測された.