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    Please use this identifier to cite or link to this item: https://tkuir.lib.tku.edu.tw/dspace/handle/987654321/74754

    Title: 以反應曲面法(RSM)探討移動結晶床除鉛之研究
    Other Titles: Using response surface methodology to investigate moving-bed reactor for lead removal
    Authors: 翁上紘;Weng, Shang-Hung
    Contributors: 淡江大學水資源及環境工程學系碩士班
    Keywords: 移動結晶床;流體化床;碳酸鉛;反應曲面法;Moving-bed reactor;Fluidized-bed reactor;lead carbonate;response surface methodology(RSM)
    Date: 2011
    Issue Date: 2011-12-28 19:25:20 (UTC+8)
    Abstract: 流體化床結晶軟化反應槽常用的操作方式,系統中使擔體流體化之上升流速會將因過飽和產生的懸浮固體物帶出槽體,導致出流水濁度偏高,因此需在流體化床後面增設一過濾單元來防止出流水含有大量的懸浮固體物,此一設計不僅佔地面積大且會增加建設費用成本。有鑑於此,本研究設計一新反應槽「移動結晶床」並以鉛做為汙染物來探討反應槽之可行性,此反應槽不僅佔地面積小且兼有結晶與過濾效果兩種功能,可改善流體化床操作之問題。
    Fluidized-bed type reactors are frequently used in crystallization process. In this type of reactor, suspend solids (SS) produced by primary nucleation under supersaturated condition would flow out with upward flow, resulting in high SS in the effluent. Installation of filter unit is needed to prevent suspend solids in the discharge. In this study, a novel reactor named “moving-bed reactor” having two functionalities, namely filtration and crystallization, was studied for lead (Pb) removal from aqueous solutions.
    According to literatures and design parameters of moving-bed reactor, five potential factors which may affect the process performance, are indentified, including lead concentration, pH, air-flow rate, the ratio of CO32-/Pb2+ and the height of sand. A 25-1 fractional factorial design is utilized to discuss the effect of factors on Pb removal efficiency, recovery efficiency and turbidity. Lead concentration and pH are the most significant factors affecting process performance. Subsequently, RSM with CCD design are used to build regression models for removal efficiency and recovery efficiency, respectively. The best operating condition was determined by uniting two regression models with pH 8.6 and 1.45×〖10〗^(-4)M of lead concentration obtained. Under the best operation condition, Pb removal efficiency and recovery efficiency are predicted to be 100.00% and 94.90%, respectively, by regression models. However, they are only 98.75% and 87.28%, respectively, experimentally. The differences are 1.25% and 8.00%, respectively, for Pb removal efficiency and recovery efficiency. The experiment can not reach the target that models predict because prediction of models is not precise.
    Based on quality analysis, crystallized Pb on the sand surface and precipitated Pb filtered by sand are 18.59% and 68.69%, respectively. The result indicated design of moving-bed reactor is inadequate to recover Pb.
    Appears in Collections:[Graduate Institute & Department of Water Resources and Environmental Engineering] Thesis

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