旋轉填充床內部之溫度分佈

The Temperature Profile in a Rotating Packed Bed

王鈺傑(Yu-Chieh Wang)

指導教授 ： 劉懷勝

國立臺灣大學/工學院/化學工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.03308

摘要

旋轉填充床為程序強化的重要項目之一，其係利用離心力所造成之高重力場取代地球之重力場，達到提升質傳效果之目的。氣液之間的質傳現象即相變化會伴隨著大量的潛熱，這顯示氣體液體之間會同時發生質量與熱量的傳遞。為了分析逆流式旋轉填充床中，液體和氣體之間的熱量質量傳遞現象，本研究以熱水和冷空氣作為系統，分別以實驗量測與理論模擬的方式，探討進料空氣的相對濕度與體積流速、進料熱水的體積流速與溫度、進料空氣與水的體積流速比例對系統的影響，並且驗證模擬與實驗之間的關聯性。

本研究於實驗中使用鈕扣型溫度記錄器，以得到各個實驗條件下床體內部不同半徑處的溫度(T_iButton)。此外，並以(Klimanek and Biaecki, 2009)提出的冷卻水塔理論作為基礎，使用簡化後的數學模型來描述旋轉填充床中水的質量流速、水的溫度、空氣溫度與空氣濕度這四個變數與徑向位置的關係；根據上述之流體變數，即可求出理論估計的溫度記錄器溫度(T_(iButton,est))。本研究中，經由實驗量測到的T_iButton與經由理論計算出的T_(iButton,est)，兩者之間的誤差不超過5%，由此可知本研究所提出之理論模型，能夠解釋氣體液體之間同時發生的熱量與質量傳遞現象，對於將旋轉填充床應用在蒸餾、化學反應等與溫度相關之程序上，提供了嶄新的思考方向與詳細的基礎研究資料。

關鍵字

旋轉填充床 ； 熱質傳數學模型 ； 床體內部之溫度量測

並列摘要

A so-called rotating packed bed (RPB) which substitutes the centrifugal force for gravitational force plays an important role in field of process intensification. With the help of centrifugal force, a better mass transfer efficiency could be expected. Because gas-liquid mass transfer which is phase change involves a large amount of latent heat, heat transfer occurs simultaneously. In this study, the phenomena of heat and mass transfer were investigated in the water-air system. The air flow rate, water flow rate, air temperature, water temperature, humidity of air and the ratio of air to water flow rate were taken into consideration in simulation and experiments. Finally, the relationship between simulation and experiments was discussed.

The temperature profile (T_iButton) was obtained by iButton® temperature data loggers at different experimental conditions and positions. Based on the theory of cooling tower proposed by Klimanek and Biaecki, this study used the modified model to describe four dependent variables (temperature of water、 temperature of air、 humidity of air、 mass flow rate of water) and the independent variable (the radial position in the RPB). With the gas and liquid data from simulation, the T_iButton can be estimated (T_(iButton,est )). In this study, the error between T_iButton and T_(iButton,est ) was smaller than 5%, so the modified model in this study can explain the phenomena of heat and mass transfer between gas and liquid phases. Therefore, the study provided not only the brand-new thinking but also plenty of basic research data for the application of temperature-sensitive chemical engineering processes in the RPB.

並列關鍵字

rotating packed bed(RPB) ； HIGEE ； the heat and mass transfer mode ； the measurement of temperature in the RPBl

參考文獻

Berman L.D. (1961) Evaporative cooling of circulating water 2nd ed. Chap. 2:94-99.

Bosnjakovic F. (1965) Technische Thermodynamik.

Burns J.R., Ramshaw C. (1996) Process intensification: Visual study of liquid maldistribution in rotating packed beds. Chemical Engineering Science 51:1347-1352.

Burns J.R., Jamil J.N., Ramshaw C. (2000) Process intensification: operating characteristics of rotating packed beds -- determination of liquid hold-up for a high-voidage structured packing. Chemical Engineering Science 55:2401-2415.

Chandra A., Goswami P., Rao D. (2005) Characteristics of flow in a rotating packed bed (HIGEE) with split packing. Industrial & Engineering Chemistry Research 44:4051-4060.