氣泡式流體化床中壓力擾動與氣體混合之關聯性研究

The relationship between the pressure fluctuations and gas mixing within a bubble fluidized bed

張綺伶(Chi-Ling Chang)

指導教授 ： 錢建嵩

中原大學/工學院/化學工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500490

摘要

本研究係於一截面積0.4 m × 0.2 m，高1.4 m之方形透明壓克力流體化床冷模中進行，使用之氣體分佈器為水平噴嘴型式氣體分佈器，床質為粒徑545 μm玻璃珠粒子。主要操作參數為空床氣速、靜床高與氣體分佈器開孔比，將探討操作參數改變時，流體化床內之流體化現象及壓力擾動，並將壓力擾動實驗結果與林美秀(2004)研究之氣體混合結果作一關聯性之探討。
壓力擾動實驗中，將壓力量測探針伸入流體化床內，量測床內之擾動特性，利用資料擷取系統（Data Acquisition System, PC-Streamer, AdvanTech Inc.）收集實驗數據，再由個人電腦收錄，並以統計函數分析處理。實驗所得之壓力擾動資料將與操作參數效應作一討論。
實驗結果顯示，流體化床內壓力擾動會隨著空床氣速增加而擾動增加；當選擇較大開孔比之氣體分佈器時，床內擾動亦隨開孔比增大而增強；當靜床高愈高，床內擾動就愈大。此三操作參數中，靜床高及開孔比對於壓力擾動之效應較氣速效應強烈。流體化床內壓力擾動與氣體混合關聯性探討結果發現，當空床氣速增加時，流體化床內之混合效果較好，流體化品質亦隨之提高。使用較大開孔比氣體分佈器時，床內之混合效果變差，流體化品質亦降低。當靜床高增高時，床內之混合效果隨之變好，但流體化品質卻隨之變差。由此得知，於較高氣速操作下，選擇小開孔比之氣體分佈器，可得到較好之混合效果及流體化品質。

關鍵字

混合指數 ； 壓力擾動 ； 氣體混合 ； 流體化指數 ； 氣泡式流體化床

並列摘要

The experiments were carried out in a cold model system of a fluidized bed with 0.4 × 0.2 m dimension, equipped with a horizontal nozzles type gas distributor. The effects of superficial gas velocity, open area ratio and static bed height on pressure fluctuation were studied. The relationship between the pressure fluctuations and gas mixing will be discussed.
In this pressure fluctuation experiment, a pressure probe was used to measure the pressure signals in the fluidized bed. Software DASY Lab was used to acquiring and analyzing the experimental data of pressure fluctuations. Pressure fluctuations in the fluidized bed will be discussed when operating parameters were been changed.
The results of experiments indicate that the effects of the superficial gas velocity and open area ratio on gas mixing are more significant than the effect of static bed height. The effects of open area ratio and static bed height on pressure fluctuations are more significant than the effect of superficial gas velocity. The fluidization index increases with the mixing index under the operating parameters at various relative gas velocities and open area ratio. When the fluidized bed was operated at higher superficial gas velocity, the gas mixing is well and the fluidization is good in the bed. When the fluidized bed was operated at larger open area ratio, the gas mixing is worse and the fluidization is worse in the bed. Under the operating parameters at various static bed heights, the fluidization index decreases with the mixing index. At higher static bed height, the fluidization is worse and the mixing is better in the bed.

並列關鍵字

fluidization index ； gas mixing ； bubble fluidized bed ； pressure fluctuations ； mixing index

參考文獻

林延金，【流體化床中壓力擾動及徑向氣體混合之研究】，中原大學化工所博士論文 (2002)。

林美秀，【流體化床中水平噴嘴分佈器對氣體混合之效應】，中原大學化工所碩士論文 (2004）。

Baeyens, J. and D. Geldart, “An investigation into slugging fluidized beds,” Chem. Eng. Sci., 29, 255-265 (1974).

Baird, M. H. I. and A. J. Klein, “Spontaneous oscillation of a gas-fluidised bed,” Chem. Eng. Sci., 28, 1039-1048 (1973).

Baskakov, A. P., V. G. Tuponogov and N. F. Filippovsky, “A study of pressure fluctuations in a bubbling fluidized bed,” Powder Technol., 45, 113-117 (1986).