曝气和射流的气泡分布与综合式泡沫分离效果研究  

Aeration and Venturi Jet-based Bubble Distribution and Effects of Integrated Foam Fractionation

作　　者：季明东[1] 李建平[1] 叶章颖[1] 朱松明[1] JI Mingdong;LI Jianping;YE Zhangying;ZHU Songming(College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China)

机构地区：[1]浙江大学生物系统工程与食品科学学院,杭州310058

出　　处：《农业机械学报》2020年第9期304-310,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家重点研发计划项目(2017YFD0701703、2019YFD0900500);浙江省重点研发计划项目(2019C02084)。

摘　　要：为提高循环水养殖中细微悬浮颗粒物的泡沫分离效率,试验研究了水体盐度、进气量对曝气和射流气泡分布的影响,根据相关泡沫分离理论,提出结合曝气和射流协同作用的综合式泡沫分离,并分析了颗粒物去除效果。结果表明:随着水体盐度增加,曝气和射流气泡的索特平均直径(SMD)减小,持气率增大;随着进气量减少,曝气和射流气泡的SMD减小,持气率也减小;曝气气泡的SMD一般大于射流。在试验条件下,综合式泡沫分离的持气率可达0.100,而曝气式、射流式分别为0.031、0.074;颗粒物去除率达到55.84%,曝气式、射流式分别为19.06%、39.67%,且曝气式对粒径小于50μm的颗粒物去除较好,而射流式使得较大粒径颗粒物破碎成2~30μm的颗粒物。综合式泡沫分离可以节约能耗,总体减少了由射流产生的粒径2~15μm细微颗粒物。Removing suspended solids,including uneaten feed and feces,is the crucial water treatment process for maintaining the stable operation in recirculating aquaculture system(RAS).The accumulating of fine particles in recirculating water is unavoidable.It has been a main bottleneck for the fast development of RAS.Considering the low efficiency of foam fractionation,the bubble distribution of aeration and venturi jet were studied.Results showed that both for aeration and venturi jet,with the increase of water salinity,the Sauter mean diameter(SMD)was decreased and the gas holdup was increased.With the decrease of air inflow,the SMD and gas holdup were decreased.In general,the SMD of aeration was larger than that of venturi jet.The analysis of relevant flotation theories revealed that the key factor of foam fractionation for fine particle was bubble-particle collision probability mainly depended on the bubble diameter and particle size.The surfactant was basic condition,and it affected bubble-particle adhesion probability,foamability and foam stability.However,the surfactant,as well as the size of fine particles,was uncontrolled in RAS.It suggested that bubble characteristics may be the leading factor for the foam fractionation of fine particles.In addition,bubbles with different diameters showed different removal effects of fine particles.Then,an integrated foam fractionation of the synergy between aeration and venturi jet was therefore proposed.The gas holdup could reach 0.100(aeration and venturi jet alone were 0.031 and 0.074,respectively),and the removal efficiency of fine particles could reach 55.84%under experimental conditions(aeration and venturi jet alone were 19.06%and 39.67%,respectively).The aeration-based foam fractionation had a good effect on the removal of fine particles which were smaller than 50μm.The venturi jet-based foam fractionation probably led to the breakup of relatively large particles,and the increasement of fine particles that were 2~30μm.Nevertheless,the integrated foam fractionation co

关 键 词：循环水养殖 细微颗粒物 泡沫分离 气泡 颗粒物粒径 

分 类 号：S238[农业科学—农业机械化工程] S959[农业科学—农业工程]