在奈米微粒的製程中，液相法為最常使用的一種方法，因此乾燥是一個重要且必須的步驟，不同的乾燥方法影響生產物的粒徑和凝聚現象的程度。本文嘗試利用水在低於液汽臨界壓力的壓力下會瞬間汽化的特性，來達到乾燥的製程。

本文裏首先建立一簡單的真空乾燥實驗，並以粉體粒徑為200nm的氧化鋁漿料為實驗材料，將漿料通入一真空的腔體中，使漿料中的液態水瞬間汽化，並收集乾燥後之粉末，觀察其顯微結構，觀察結果顯示乾燥後的粉體顆粒形狀和粒徑都與在漿料中原始形狀沒有太大差異，因此評估真空膨脹不失為一種好的乾燥方法。

在確認真空膨脹法對漿料乾燥的效果後，為了達到連續性的乾燥製程，本文提出利用溴化鋰溶液吸濕的特性，設計一連續性的真空乾燥概念系統，並以ABSIM軟體模擬此乾燥系統來得到未來製程之操作參數，以利往後製造連續性真空乾燥設備之重要參數。

Drying is a necessary step during the entire production processes of obtaining nano-size particle by the liquid-phase method. A serious agglomeration among nano-particle will occur when the slurry is dried out by the traditional oven-drying method. In this study, the drying of slurry is achieved by injecting the slurry into a vacuum chamber and the water of slurry will instantaneously flash out.

A simple vacuum chamber with a two-step closely tighted needle valves was set-up to perform the flash out test, and the slurry with 200nm α-Al2O3 particle was the experimental material. The resulting dry α-Al2O3 was examinated by SEM. From the test results, it is confirmed vacuum drying can prevent the serious particle agglomeration.

In order to perform the vacuum dry continuously, a conception system is proposed in this study. In the system the degree of vacuum can be effectively maintained when the flash out vapor is continuously absorbed by LiBr solution. The operation of the proposed system is also simulated by using ABSIM code, the resulting state conditions and parameters are believed to be beneficial to provide valuable information for setting up the future facility.

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