矽膠乾燥劑廣泛應用於許多工業除濕過程，如射出成形原料之乾燥過程與太陽能蒸發式除濕空調系統等。其中為了幫助這些工業應用上的系統設計，必須瞭解矽膠吸脫附水汽反應中的質傳機制。在目前已存在之矽膠吸脫附水汽系列研究中，SSR模型 (solid-side resistance model) 因考量了多孔性矽膠之固體側質傳阻抗，故較過去的PGC模型 (pseudo-gas-side controlled model) 能更準確預測矽膠吸脫附水汽反應之過程。
而為了確認考量矽膠顆粒內部熱傳導阻抗與否，對SSR模型模擬結果之差異性大小，在本研究中我們透過改變Biot數對該兩種SSR模型進行討論。其中由於Biot數受矽膠粒徑與對流熱傳係數影響，而對流熱傳係數又由進口空氣流速決定，所以矽膠粒徑與進口空氣流速為影響兩種SSR模型模擬差異大小之重要因素。另一方面由於矽膠吸水為放熱反應，而溫升將造成矽膠吸附能力降低，亦即溫度為矽膠吸附反應之重要因素，故矽膠床進口空氣溫度亦為其水汽吸附反應值得探討之參數。
本研究中我們透過SSR模型模擬矽膠吸附水汽之反應，發現當進口空氣流速越大、矽膠粒徑越小時，前者將使總吸附水量上升較快，後者則相反，但兩者均會提前各反應階段的轉換時間，並使忽略熱傳導阻抗之差異較顯著。另一方面當進口空氣溫度提升時，系統整體溫升快，總吸附水量上升較慢。此外我們亦發現當我們發現當改變進口空氣流速或溫度時，忽略熱傳導阻抗均會使各反應階段的轉換時間較晚開始。
同時，在本研究中我們亦利用SSR模型針對本研究團隊過去所建立之實驗結果進行模擬比較。根據比較結果我們發現SSR模型因未考量實驗中空氣流速會隨著反應器軸向位置遞增而下降的現象，以及SSR模型缺乏考量實驗中填充床反應器壁面水流之對流散熱效果，造成其低估了系統整體散熱的速率。故本文中我們分別建議在SSR模型中增加Darcy定律以預測局部空氣流速，並且將SSR模型由僅含矽膠床一維軸向方向改為增加考量其徑向方向，再於矽膠床壁面增加對流散熱效果，以提高SSR模型模擬該實驗之準確性。

Silica-gel desiccant is widely used in various industrial dehumidifying processes. To help improve such system design, it requires understanding of the heat and mass transfer mechanism during moisture adsorption/desorption process of silica gel. Among current research models, SSR (solid-side resistance) model, with additional consideration of intraparticle mass transfer resistance, usually can predict more accurately than the earlier PGC (psuedo-gas-side controlled) model does. However, in previous studies, the effect of adjusting the key system parameters, and that of intraparticle thermal resistance, on silica-gel adsorption process have not been discussed. In the present study, it is found that increasing the inlet air velocity and temperature and the desiccant particle radius make the total mass of water adsorbed by silica gel increase faster. Besides, increasing the inlet air velocity and decreasing the particle radius make the effect of neglecting intraparticle thermal resistance in SSR model more remarkable.
On the other hand, to make SSR model fit the previous silica-gel adsorption experimental results in our research team more properly, we also use SSR model to simulate and compare with the results of the experiment. It is recommended that adding Darcy’s law in SSR model, extending SSR model from 1-D (with axial direction) to 2-D (with both axial and radial directions), and taking the heat convection on the wall of the reactor into account.

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