本論文以混合時間與軸向分散係數為指標，探討網狀內管氣舉式反應器在各操作條件下之液相混合性能。實驗使用26升網狀內管氣舉式反應器，以空氣作為氣體，水或CMC溶液作為液體。操作變數包括氣體流速、網目大小、內管直徑、內管長度、頂部液體高度、反應器高度、固體負荷量以及液體性質，並採用注入追蹤劑方法以及Ohki和Inoue (1970) 所提之分析方法來估算液相軸向分散係數。
實驗結果得知，網狀內管氣舉式反應器的液體流動行為較傾向氣泡床，而偏離傳統實壁管氣舉式反應器。因此，其可視為一種改良式之氣泡床。由於仍保有液體循環特性，再加上氣、液可在網管間來回穿梭，故其混合時間遠低於氣泡床，且網目愈小之網狀內管氣舉式反應器，其混合效能愈佳，但軸向分散係數在高氣速操作下略低於實壁內管氣舉式反應器。

軸向分散係數與反應器內流體的流動型式有關，大致上隨氣速增加而增加，惟在流動型式改變的過渡期時，隨氣速增加而減少。內外管直徑比為0.6時，具有較佳的混合。內管長度愈高，液體流速增加，混合效果愈好。頂部液體高度增加，對軸向分散係數影響不大，當增加至一定值後，軸向分散係數開始下降。軸向分散係數不隨反應器高度而改變。

此外，固體粒子具有攪拌作用，因此增加固體粒子可以提高軸

向分散係數，降低混合時間。黏度增加會促使氣泡融合，平均氣泡

直徑增加，所以黏度愈高，混合效能愈好。軸向分散係數與混合時間可由經驗方程式預測之，誤差在正負30%內。

Liquid mixing characteristics were studied for the airlift reactor operating with net draft tube. The experimental reactor had a working volume of 26 L, column diameter of 0.13 m, and total height of 2 m. Experiments were carried out using air, water (or CMC solution), and polystyrene particles. Mixing in the liquid phase was assessed by the tracer-response technique and fast conductivity measurements.
It was found that the flow pattern in an airlift reactor with net draft tube was similar to that in bubble columns instead of traditional airlift reactor. The mixing time decreased and the axial dispersion coefficient increased with increasing net mesh number. Moreover, the axial dispersion coefficient increased while rising superficial gas velocity except the transition from bubbly to churn-turbulent flow regime. The better diameter ratio of draft tube to column was 0.6, and the reactor with higher draft tube had better mixing performance. However, the top section had slight influence on liquid mixing, and the dispersion coefficient didn’t change with the reactor. Furthermore, adding solids and increasing liquid viscosity would enhance the mixing efficiency. In addition, the correlation between dispersion coefficient and these variables was established and the observed values were in agreement with the calculated values with a deviation of 30 %.

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