https://scholars.lib.ntu.edu.tw/handle/123456789/77158
Title: | 迴流式氣泡反應槽臭氧處理程序之動態模式及其模型廠規模試驗(2/2) A Dynamic Model and Pilot-Scale Study for Ozonation in a Recirculating Bubble Column Reactor (II). Part 1: Ozonation of Pollutants in a Recirculating Bubble Column |
Authors: | 張慶源 | Keywords: | 臭氧;污染物之臭氧化;動態軸 向延散模式;迴流式氣泡反應槽;ozone;ozonation of pollutants;dynamic axial dispersion model;recirculating bubble column reactor | Issue Date: | 31-Jul-2003 | Publisher: | 臺北市:國立臺灣大學環境工程學研究所 | Abstract: | 本研究建立一迴流式污染物臭氧化氣 泡反應槽之動態臭氧傳輸模式。氣泡反應 槽已廣泛應用於實廠或實驗室中作為臭氧 氣液的接觸設備。臭氧的產生大多是將氧 氣通入臭氧產生機而產生出臭氧及氧氣的 混合氣體,再將之導入氣泡反應槽底部的 氣體分散設備。此臭氧氣液接觸系統在達 到系統濃度穩定前,會經過一段過渡期即 非穩定態的過程。目前常見氣泡反應槽的 臭氧傳送模式,大多只能用來描述穩定態 時臭氧及污染物質的濃度分佈。此外氧氣 的質量傳送通常都被忽略,因此水中所增 加的溶氧量較少被探討。然而要適當操作 一臭氧氣泡反應槽,這些資訊應是有必要 加以瞭解的。本研究建立適當的模式來描 述及探討氣泡反應槽中污染物臭氧化的動 態傳送過程並考慮氧氣的質量傳送。所提 出的動態軸向延散模式,可用來預測氣泡 槽中臭氧、氧氣、和污染物質的濃度分佈 及變化。研究中並進行相關的污染物臭氧 化實驗,將實驗數值與模擬結果做比較來 驗證模式的有效性。一般而言臭氧氣泡反 應槽需要2 到5 個水力停留時間才會趨近 於穩定態。本研究另一方面探討當反應槽中有部分液體迴流時,對於臭氧氣泡反應 槽處理效能所造成的影響。結果發現當有 部分液體迴流時,會影響反應槽中臭氧及 污染物質的濃度分佈及系統有效的接觸時 間(t10),在接近反應槽的液體進流位置溶臭 氧及污染物濃度會分別上升及下降,而t10 會隨著液體迴流量而減小,對於出流水中 的溶臭氧及污染物濃度則沒有顯著影響。 因此本研究所提出之動態臭氧及污染物傳 輸模式對於預測及模擬迴流式臭氧氣泡槽 反應槽甚為有用及有效。 The dynamic process of ozonation of pollutants in a recirculating bubble column is studied for the model establishment. Bubble columns have been widely used for ozone contacting in plants and laboratories. Ozone is produced by oxygen-enriched gas through an ozone generator, and introduced into the bottom of the column equipped with the gas-diffuser. The ozone contacting system exists a temporary or unsteady period before reaching the steady state. Available ozonation models employed for thedescription of the concentration profiles of ozone and pollutant have been commonly developed for the steady state. Moreover, oxygen mass transfer is usually neglected in the preceding ozonation models. However, this information is desirable for the proper operation of ozonation of pollutants in a bubble column. Thus, the objective of this study is to model and investigate the dynamic process of ozonation in a bubble column with oxygen mass transfer. The dynamic axial dispersion model (DADM) is employed to predict the variations of concentrations of ozone, oxygen, and pollutant along the column, and the amount of off-gas. The validity of model is demonstrated by comparing the predicted results with the experimental data. Furthermore, the effects of partial recirculation of liquid on the concentration profiles and effective contact time (t10) are investigated. The concentrations of dissolved ozone and pollutant near the liquid inlet of the bubble column increase and decrease with recirculation, respectively. The t10 decreases with the amount of liquid recirculation. However, the effect of liquid recirculation on the effluent concentrations of dissolved ozone and pollutant is found slight. The dynamic ozonation model proposed is useful and referable for the proper prediction of the variables of the ozonation system of pollutants in a bubble column. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/22121 | Other Identifiers: | 912211E002069 | Rights: | 國立臺灣大學環境工程學研究所 |
Appears in Collections: | 環境工程學研究所 |
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912211E002069.pdf | 471.77 kB | Adobe PDF | View/Open |
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