环流重数对生物流化床液相流场和氧传质特性的影响  

Effect of Circulation Multiplicity on Liquid Flow Field and Oxygen Mass Transfer Characteristics in Biological Fluidized Bed

作　　者：董亮 曾涛 徐银香 崔亚辉[1] 赵桐[1] DONG Liang;ZENG Tao;XU Yinxiang;CUI Yahui;ZHAO Tong(School of Mechanical and Precision Instrument Engineering,Xi'an University of Technology,Wan 710048,China;Department of Mechanical and Electrical Engineering,Nanchong Vocational Technology College,Nanchong 637131,China;School of Mechanical Engineering,Sichuan University of Science&Engineering,Yibin 644002,China)

机构地区：[1]西安理工大学机械与精密仪器工程学院,陕西西安710048 [2]南充职业技术学院机电工程系,四川南充637131 [3]四川轻化工大学机械工程学院,四川宜宾644002

出　　处：《安全与环境工程》2022年第6期217-223,239,共8页Safety and Environmental Engineering

基　　金：四川省科技创新苗子工程项目(2929131);国家自然科学基金青年科学基金项目(51808362);南充市科技局项目(19YFZJ0008);南充市社科联项目(NC2018C038);成都水生态文明建设研究重点基地资助项目(2018SST-07)。

摘　　要：针对生物流化床内构件设计问题,提出通过剖析生物流化床液相速度和氧传质特性的方法,用以实现生物流化床最优结构设计的目的。应用激光粒子图像测速(PIV)和溶解氧在线测试技术,分析了不同环流重数和曝气强度对生物流化床液相速度和氧传质特性的影响,并通过比较分析两张图像获得粒子的位移,根据速度的基本定义和PIV算法得出生物流化床全局液相流场的速度矢量图,同时采用氧转移系数(K)和氧转移效率(Eo)表征生物流化床氧传质特性。结果表明:通过分区拍摄、拼接生物流化床液相速度矢量图和采用0.4%浓度的椰壳活性炭填料,较好地实现了气-固-液三相流的PIV可视化试验和全局液相流场特性的呈现;随着曝气强度的增加,与一重环流生物流化床相比,当生物流化床环流重数为二重和三重时,升流区的沟流区域液相速度逐渐降低,降流区的液相速度逐渐增快,该生物流化床液相流场特性有效提高了氧传质效率;相比传统的生物流化床,当生物流化床为三重环流时,K_(La)和Eo_(2)的整体效率最优,该生物流化床结构更有利于降低能耗、节约成本。Aiming at the problem of designing the internal components of biological fluidized bed, the me-thod of analyzing the liquid phase velocity and oxygen mass transfer characteristics was proposed, in order to realize the optimal design of biological fluidized bed.Through applying laser particle image velocimetry(PIV) and dissolved oxygen online testing techniques, the effects of different aeration intensities and circulating multiplicity on liquid phase velocity and oxygen mass transfer characteristics were analyzed.The particle displacement was obtained based on the comparative analysis of the two images, and the velocity vector diagram of the global flow field of the liquid phase of biological fluidized bed was obtained according to the basic definition of velocity and PIV algorithm.Meanwhile, the oxygen transfer coefficient(K) and oxygen transfer efficiency(Eo) were used to characterize the oxygen mass transfer characteristics in biological fluidized bed.It is shown that the PIV visualization experiment of gas-solid-liquid three-phase flow and the presentation of global liquid phase flow field characteristics are well realized by zonal shooting, splicing speed vector diagram and adopting 0.4% concentration of coconut shell activated carbon filler.With the increase of aeration intensity, compared with the one circulating biofluidized bed, the liquid phase velocity of the ditch in the upflow area is gradually reduced, and the liquid phase velocity in the descending region is gradually increased when the circulating weight of bio-fluidized bed is double and triple, and the flow field characteristics of biological fluidized bed can effectively improve the oxygen mass transfer efficiency.Compared with traditional bio-fluidized bed, three circulating bio-fluidized bed has the overall optimal efficiency of K_(La) and Eo_(2),and this structure of biological fluidized bed is more conducive to reducing energy consumption and saving costs.

关 键 词：生物流化床 环流重数 液相速度 氧传质特性 粒子图像测速(PIV) 

分 类 号：X703[环境科学与工程—环境工程]