单孔及微孔曝气低气速鼓泡床内气泡行为比较  

Comparison of bubble behavior between single orifice and porous spargers air-water bubble columns

作　　者：梁斌[1] 胡强[1] 周慧[1] 张全忠[1] 沈伟[1] 

机构地区：[1]四川大学化工学院,四川省多相流传质与反应工程重点实验室,四川成都610065

出　　处：《化工学报》2005年第10期1880-1886,共7页CIESC Journal

基　　金：国家自然科学基金项目(20233040).~~

摘　　要：Bubble dispersion greatly relies on spargers. Single or ifice and porous spargers were tested inside a bubble column under a low gas thr oughput to study their influences on gas dispersion and gas-liquid interface ar ea. A PBE model without considering the effect of bubble coalescence was develo ped to describe axial bubble distribution. Both simulation and experimental res ults showed that bubbles broke up much faster than coalesced under low gas veloc ity. For a single orifice sparger, breakage was a dominant feature for bubbles after they left the orifice. Initial bubbles formed over the orifice were mostl y larger than the largest stable bubble. They broke up quickly and their sizes were reduced below the maximum diameter d_s of stable bubbles. In contrast , a porous sparger produced a large amount of initial bubbles smaller than the l argest stable bubble. The bubbles possessed smaller size and narrower distribut ion compared with the bubbles obtained by single orifice spargers. With the por ous sparger, gas-liquid surface area was increased by 5—6 times even though th e gas holdup changed insignificantly. High mass transfer area could be obtained by injecting more small initial bubbles with diameters under d_s.Bubble dispersion greatly relies on spargers. Single orifice and porous spargers were tested inside a bubble column under a low gas throughput to study their influences on gas dispersion and gasliquid interface area. A PBE model without considering the effect of bubble coalescence was developed to describe axial bubble distribution. Both simulation and experimental results showed that bubbles broke up much faster than coalesced under low gas velocity. For a single orifice sparger, breakage was a dominant feature for bubbles after they left the orifice. Initial bubbles formed over the orifice were mostly larger than the largest stable bubble. They broke up quickly and their sizes were reduced below the maximum diameter ds of stable bubbles. In contrast, a porous sparger produced a large amount of initial bubbles smaller than the largest stable bubble. The bubbles possessed smaller size and narrower distribution compared with the bubbles obtained by single orifice spargers. With the porous sparger, gas-liquid surface area was increased by 5-6 times even though the gas holdup changed insignificantly. High mass transfer area could be obtained by injecting more small initial bubbles with diameters under ds.

关 键 词：鼓泡床 气泡 分布器 传质 

分 类 号：TQ021.1[化学工程]