微細粒子流體化之研究

Fluidization of Fine Particles

姜智鈞(Chih-chun chiang)

指導教授 ： 錢建嵩

中原大學/工學院/化學工程研究所/碩士(2003年)

https://doi.org/10.6840/cycu200300615

摘要

本研究係於一截面0.15 m × 0.015 m的二維流體化床和一內徑 0.07 m的三維圓形流體化床之冷模系統中進行，使用多孔板及水平噴嘴氣體分佈器測試微細粒子流體化的特性，並探討氣速、粒徑、靜床高及床質粒子特性對壓力擾動的效應。
以壓力探針深入床內不同徑向位置量測壓力訊號，利用DASYLab軟體擷取數據，並以統計的方法，求出壓力擾動之振幅及其平均值、標準偏差及變異係數。當所得到壓力擾動之變異係數較低時，代表振幅擾動程度較相近，意味著床內流體化行為較為一致，並利用頻譜分析圖判斷床內流體化之型態。
結果顯示，雖然床質粒徑皆小於20 μm，粒子流體化特性卻不全然相同，不同分佈器設計會對微細粒子流體化行為產生影響。微細粒子擾動振幅隨氣速、粒徑和靜床高的增加而增加，氦氣的加入可幫助粒子分散，提升流體化品質。

關鍵字

流體化 ； 微細粒子

並列摘要

This experiments were carried out in a cold model system of a 2-D fluidized bed with an across section of 0.15 m × 0.015 m and a 0.07 m I.D. 3-D fluidized bed. The porous plate and horizontal nozzles were used as gas distributor to study the behavior of fine particles fluidization. The effects of gas velocity, particle size, static bed height and different bed materials on the pressure fluctuations were studied.
Radial pressure signals were measured by a pressure probe, which could be inserted at a desired position in the fluidized bed. Software DASYLab were used to acquire data, calculating the mean of pressure drop and amplitude and the standard deviation and the variance of amplitude. When the value of coefficient of variance was low, it implied that the degrees of pressure fluctuation at different radial positions were similar. Spectral analysis was used to judge the fluidization regime.
The results revealed that although the sizes of all bed materials were small than 20 μm, the characteristics of fluidization of these fine particles were not the same. Different design of gas distributor would make effect on the behavior of fine particle fluidization. The amplitude of fine particles fluidization increases with superficial velocity, particle size and static bed height. Adding Helium can help particles disperse and it can improve the quality of fluidization.

並列關鍵字

fine particle ； fluidization

參考文獻

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