曝气密度对曝气系统充氧性能的影响研究
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摘要
曝气密度(即曝气面积占曝气系统服务总面积的比率)是曝气系统重要的参数之一。以标准氧总转移系数作为评价指标,在小试装置中对不同曝气密度的曝气系统充氧性能进行评价。结果表明:(1)曝气系统标准氧总转移系数随曝气密度增大而显著增大,但同时需要考虑到曝气系统的微孔曝气器布置方式;(2)相同气量下,曝气系统的气泡直径与气泡运动速度随曝气密度增大而减小,气泡停留时间和气含率随曝气密度增大而增大。
Diffuser density(the ratio that the diffuser area accounts for the total area of the aeration system services)is one of the important parameters for fine bubble diffusers.The paper assessed the impacts through a pilot test of aeration system of different diffuser density using standard oxygen transfer coefficient(KLas)as evaluation criterion.The results showed that:(1)KLasincreased significantly with the increasing of diffuser density,however,the layout of diffusers should be taken into consideration;(2)Under the same condition of air flow rate,when diffuser density increased,the bubble became smaller and gas velocity decreased,while the retention time and gas hold-up were increased.
Diffuser density(the ratio that the diffuser area accounts for the total area of the aeration system services)is one of the important parameters for fine bubble diffusers.The paper assessed the impacts through a pilot test of aeration system of different diffuser density using standard oxygen transfer coefficient(KLas)as evaluation criterion.The results showed that:(1)KLasincreased significantly with the increasing of diffuser density,however,the layout of diffusers should be taken into consideration;(2)Under the same condition of air flow rate,when diffuser density increased,the bubble became smaller and gas velocity decreased,while the retention time and gas hold-up were increased.
引文
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[19]MOUNIR B,GILLES H,DOMINIQUE B,et al.A comparative study of gas hold-up,bubble size,interfacial area and mass transfer coefficients in stirred gas-liquid reactors and bubble columns[J].Chemical Engineering and Processing,2001,40(2):97-111.
[2]张自杰.环境工程手册(水污染防治卷)[M].北京:高等教育出版社,1996.
[3]顾国维.水污染治理技术研究[M].上海:同济大学出版社,1997.
[4]ROSSO D,STENSTROM M K.Surfactant effects on alphafactors in aeration systems[J].Water Research,2006,40(7):1397-1404.
[5]谷成国,宋剑锋.城市污水处理厂鼓风曝气阶段的节能降耗研究[J].环境保护科学,2008,34(5):26-28.
[6]范海涛.污泥浓度对微孔曝气氧传质过程的影响[J].环境工程学报,2012,6(12):4305-4309.
[7]罗涛,王洪臣,齐鲁,等.总溶解性固体及表面活性剂对微孔曝气氧传质过程影响的中试研究[J].环境科学学报,2012,32(9):2066-2070.
[8]LEU H G,LIN S H,SHYU C C,et al.Effects of surfactants and suspended solids on oxygen transfer under various operating conditions[J].Environ.Technol.,1998,19(3):299-306.
[9]汤利华,孟广耀.曝气器的最优孔径分析[J].中国科学技术大学学报,2006,36(7):775-780.
[10]孙从军,陈季华.水温对氧转移速率的影响研究[J].环境科学研究,1998,11(4):13-15.
[11]张斌,郝玉萍,张东生,等.几种型式微孔曝气器清水充氧性能对比实验研究[J].工业安全与环保,2013,39(3):14-15.
[12]WHITMAN W G.The two-film theory of gas absorption[J].Chem.Met.Eng.,1923,29(4):1215-1220.
[13]ASCE/EWRI 2-06,Measurement of oxygen transfer in clean water[S].
[14]BURRIS V L,LITTLE J C.Bubble dynamics and oxygen transfer in a hypolimneticaerator[J].Water Science and Technology,1998,37(2):293-300.
[15]张炎,黄为民.气泡大小对反应器内氧传递系数的影响[J].应用化工,2005,34(12):734-736,740.
[16]郭瑾珑,程文,周孝德,等.小气泡扩散曝气氧传质速率研究[J].西安理工大学学报,1999,15(4):86-90.
[17]陈旭露,王洪臣,齐鲁,等.阴离子表面活性剂对微孔曝气氧传质过程影响的研究[J].环境科学学报,2013,33(2):395-400.
[18]林松.鼓泡塔中气泡尺寸分布和局部气含率研究[J].化学工程,2008,36(2):21-24.
[19]MOUNIR B,GILLES H,DOMINIQUE B,et al.A comparative study of gas hold-up,bubble size,interfacial area and mass transfer coefficients in stirred gas-liquid reactors and bubble columns[J].Chemical Engineering and Processing,2001,40(2):97-111.