Photocatalytic activity and scale-up effect in liquid-solid mini-fluidized bed reactor
Photocatalytic activity and scale-up effect in liquid-solid mini-fluidized bed reactor
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液固小型流化床反应器的光催化活性及放大效应
DOI：
10.1016/j.cej.2016.01.050
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发表时间：
2016
影响因子：
15.1
通讯作者：
Lin Cheng
中科院分区：
文献类型：
--
作者：
Yang Zhongguo;Liu Mingyan;Lin Cheng
分别将Fe 3 +/TiO 2光催化剂涂覆在流化床内壁（Fe 3 +/TiO 2/石英管）、流化颗粒表面（Fe 3 +/TiO 2/玻璃珠）或两者上，在3个微型流化床反应器中研究了亚甲基蓝的光催化降解。在Fe ~（3+）/TiO_2/石英管玻璃微珠（d= 3 mm，初始床层高度H_0 = 15 mm）反应器中，由于玻璃微珠的加入和流化作用，与空管相比，传质系数提高了11-13倍，表观反应速率常数提高了4.9倍。在Fe 3 +/TiO 2/玻璃微珠（d= 3 mm，H 0 = 15 mm）石英管反应器中，实验结果与简化的动力学模型吻合较好。对于所有内径（ID）床，单位反应体积的降解速率在空隙率为0.75时达到最高值。Fe ~（3+）/TiO_2/石英管反应器和Fe ~（3+）/TiO_2/玻璃微珠反应器结合了两种催化剂的优点，降解率比其它两种反应器提高5-35%。随着管内径的增大，反应器内存在放大效应，引入单位反应体积的Fe 3 +/TiO 2/玻璃微珠石英管（Rav，I）和单位反应体积的Fe 3 +/TiO 2/玻璃微珠石英管（Rav，II）降解速率，定量描述反应器的处理能力和放大效应。当玻璃珠从空管增加到H 0 = 15 mm时，1 mm内径床的Rav，I值为3 mm内径床的4.5 ~ 1.8倍。1 mm内径床层的Rav，II值约为3 mm内径床层的1.4-1.9倍。放大效应是由辐射通量密度、比表面积、传质距离和光穿透距离的变化引起的。
Photocatalytic degradation of methylene blue was studied in three mini-fluidized bed reactors, with Fe3+/TiO2photocatalyst coated on the inner wall of fluidized bed (Fe3+/TiO2/quartz tube), on the surface of fluidized particles (Fe3+/TiO2/glass beads) or on both. In the reactor of Fe3+/TiO2/quartz tube with glass beads (d= 3 mm, initial bed heightH0= 15 mm), due to addition and fluidization of glass beads, mass transfer coefficient increased 11–13 times and apparent reaction rate constant increased 4.9 times compared to the empty tube. In the reactor of quartz tube with Fe3+/TiO2/glass beads (d= 3 mm,H0= 15 mm), experimental results were fitted well with a simplified kinetic model. Degradation rate per unit reaction volume reached highest value at voidage of 0.75 for all inner diameter (ID) beds. In the reactor of Fe3+/TiO2/quartz tube with Fe3+/TiO2/glass beads which combined the advantages of above two forms of catalyst, the degradation ratios were 5–35% higher than that in the other two reactors. With the increase of tube ID, scale-up effect was found. Degradation rate per unit reaction volume in Fe3+/TiO2/quartz tube with glass beads (Rav,I) and that in quartz tube with Fe3+/TiO2/glass beads (Rav,II) were introduced to quantitatively describe the processing ability and scale-up effect. The values ofRav,Iof 1 mm ID bed were between 4.5 and 1.8 times to 3 mm ID bed when glass beads increased from empty tube toH0= 15 mm. The values ofRav,IIof 1 mm ID bed were about 1.4–1.9 times to 3 mm ID bed at allH0. Scale-up effect was caused by the variation of radiation flux density, specific surface area, mass transfer distance and light penetration distance.