矽膠流體化床之性能研究

流體化床有著床體性質均勻，高熱傳速率與高質傳速率等優點，若以吸附材料作為流體化床中的床質，對空調系統的外氣進行除濕工作，可有效降低潛熱負載，提高空調系統的效率。本研究分別測試平均粒徑6mm與3mm的市售矽膠顆粒作為流體化床中的吸附材料在夏季外氣條件下的吸附能力。量測流體化床在不同風速及填充高度下的吸脫附能力與壓力損失，並與固定式填充床進行比較。流體化床與固定填充床的比較實驗中，使用平均粒徑6mm的矽膠顆粒進行測試。於填充高度10cm，風速2.0m/s，吸附與脫附時間為40分鐘時的操作條件下，流體化床有效提升總吸附量20.6%，總脫附量19.9%，而空氣通過的壓力損失下降36.0%，溫度上升量下降30.0%。故流體化床更有效進行除濕工作。流體化床於不同風速與填充高度的吸附實驗中，風速的範圍操作在1.5至3.0m/s，填充高度為5cm至15cm。兩種矽膠材料的吸附與脫附性能同樣隨著風速的增加而上升。而填充高度同樣影響流體化床的性能，總吸脫附量雖然隨著填充高度上升而增加，但單位矽膠重量的吸脫附量卻隨填充高度增加而下降。本研究亦建立一流體化床吸附數學模型以預測空氣出的溫濕度及除濕性能，結果顯示預測值與實驗值相接近，誤差皆在18.8%以內，因此數學理譣模型可有效推算出流體化床的出口溫濕度與除濕性能。

關鍵字

流體化床；固定式填充床；矽膠；吸附；脫附；壓力損失

並列摘要

Fluidized bed has several advantages such as uniform bed properties, high heat and mass transfer rate. Therefore, using the silica gel fluidized device can effectively reduce the latent load and improve the efficiency of the air conditioning system. This study experimentally investigates the performance of the fluidized bed device. In the experiments, two type of commercial silica gel particle, 3mm and 6mm particle diameter, were filled in the bed and various mass flow rate of the passing air and filling quantities of the bed were tested. The results indicated that the fluidized bed has better dehumidification performance than the fixed packed bed. Compared to the fixed packed bed device, the total adsorption and desorption amounts of fluidized bed for 40 minutes increased by 20.6% and 19.9% respectively when the bed height was 10 cm and superficial velocity was set to 2m/s. In addition, under this condition, the pressure drop and outlet air temperature raise were reduced by 36.0% and 30.0%. The second part of this research study the performance of fluidized bed operated in different superficial velocity and filled bed height. For superficial velocity was set to 1.5-3.0 m/s, and filled bed height was set to 5 to 15 cm, two type of silica gel particle having a better performance of adsorption-desorption when increasing the superficial velocity or filled bed height, but the total adsorption-desorption amounts per unit weight of silica gel particle are reduced when the filled bed height increased. Finally, this research constructs a theoretical model of silica gel fluidized bed to predict the outlet temperature and humidity as the inlet temperature and humidity ratio are known. The results show that outlet temperature and humidity are well predicted by the theoretical model and the error between experiments and theoretical prediction of total adsorption amounts is less than 18.8%.