气体分布器对内循环三相生物流化床反应器动力学性能的影响  

Effects of Gas Distributors on Hydrodynamics of Three-phase Biological Fluidized Bed Reactor with Internal Circulation

作　　者：黄卫星[1] 胡培根[1] 岑斌[1] 沈琪[1] 

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《四川大学学报（工程科学版）》2015年第3期174-179,共6页Journal of Sichuan University (Engineering Science Edition)

摘　　要：通过实验手段,对3种不同分布器下内循环三相流化床反应器内的气含率εg、内循环液速Uc及体积氧传质系数KLa进行了研究。结果表明:除进气量这一直接因素外,分布器孔径及其分布密度是影响气含率的2个主要因素;相同气量下,微孔分布器有助于获得较高气含率,但气孔分布过于密集(陶瓷分布器)则会使气泡在脱离阶段发生聚并增大,导致气含率降低。循环液速Uc在低气量下(Qg<260 L/h)主要由升降流区的气含率差Δεg控制,高气量下则由Δεg和回路阻力共同控制;相同气量下,不同分布器对应的循环液速Uc则主要取决于气含率差Δεg,分布器对应的Δεg较大,其Uc也相应较高。体积氧传质系数KLa随进气量增加而增大,其中主要贡献是气含率增大导致的比表面积a增大;相同气量下,分布器对应的气含率较高,其KLa也相应较高。The gas hold-up,liquid circulation velocity and volumetric oxygen mass transfer coefficient were investigated by experiments in an internal circulation three-phase biological fluidized bed reactor with three different gas distributors. The results showed that,besides the gas flow rate Qg,the gas hole diameter and the hole number per unit area of distributor are also important factors that affect gas holdup εginside the reactor. Under a given Qg,the distributor with smaller hole helps to achieve higher εg( as did the micropore distributor in this work),but the over-densely distributed holes on distributor will cause the small bubbles to merge into large bubbles,leading to decreased εg( as did the ceramic distributor in this work). For the cases of lower gas flow-rate( Qg< 260 L / h),the liquid circulation velocity Ucmainly depends on the gas holdup difference Δεgbetween riser and downcomer,while for the cases of higher gas flow-rate,both Δεgand flow resistance are dominating factors. When Qg keeps constant,the distributor which achieves a larger Δεgleads to a higher circulation velocity. The volumetric oxygen mass transfer coefficient KLa increases with increasing Qg,to which the increased specific surface area contributes mostly. Under a given Qg,the distributor which achieves a higher gas holdup results in a higher mass transfer coefficient KLa.

关 键 词：三相流化床反应器 气体分布器 气含率 循环液速 体积传质系数 

分 类 号：X703.3[环境科学与工程—环境工程]