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The Hydrodynamic Characteristics Of Slurry Bubble Column Reactors With Elevated Pressure

Posted on:2005-12-20Degree:MasterType:Thesis
Country:ChinaCandidate:S H YangFull Text:PDF
GTID:2121360125968052Subject:Chemical Engineering
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Slurry Bubble Column Reactor (SBCR) has found applications in anumber of chemical, biochemical and environmental processes, becauseof many advantages over other multiphase reactors, such as simpleconstruction, good mass transfer properties, high thermal stability, lowenergy supply and hence low construction and operation costs. Thehydrodynamic behavior plays an important role in the design, scale-upand operation process of SBCR. However it still faces much difficult dueto complex hydrodynamic consideration, especial at industrial conditionof high pressure and high temperature. As background of the industrial process of p-xylene oxygenationand design requirement, the experimental apparatus of SBRC with 0.3 min diameter and 6.6 m in height and pressure up to 4.0 MPa was set up.air-water-quartzite and air-acetic acid-PTA systems were respectivelyemployed to study basic variations of gas holdups, bubble populationand the rising velocities of small bubble swarm and large bubble swarm III北 京 化 工 大 学 硕 士 论 文using Dynamic Gas Disengagement (DGD) and γ-ray Attenuationtechnology. The results show, as follow: 1. The small bubble is the main compose of gas holdup in SBRCwith pressurized condition. The system pressure may impede bubblecoalescence, and holdups of small bubble increases with an increase ofsystem pressure. The superficial velocity mainly increased holdups oflarge bubble in churn-turbulent flow regime. Moreover the average gasholdup decreases with increase of solid holdup, surface tension andliquid viscosity, respectively. 2. The axial concentration of solid is close to an uniformitydistribution with increase of gas velocity and decrease of solidconcentration, and system pressure only slightly affected the axialdistribution of solid. 3. The rising velocity of bubble swarm decreases with an increase ofsystem pressure. The rising velocity of small bubble swarm only slightlyaffected by superficial velocity and solid concentration. However therising velocity of large bubble increases with increase of superficialvelocity and solid concentration . 4. According to the experimental data, a correlation of average gasholdup, small bubble holdup and large bubble holdup are obtained: εg=0.576Ug0.32(ρ0 )0.15(σ0 )-0.16(μμ0 ) ρ σ sl -0.36 εsmall=0.184Ug0.15( ρρ0 )0.32( μμ0 )-1.22 g sl IV北 京 化 工 大 学 硕 士 论 文 εlarge=0.785Ug 0.64( ρρ0 )-0.14( μμ0 )-0.13 g sl 5. The rising velocities of large and small bubble swarm areobtained within the range of experimental condition, respectively: vsmall=0.194Ug-0.10(ρρ0 )-0.29(μμ0 ) g sl -0.60 vlarge=1.67Ug 0.57(μμ0 ) sl 2.53...
Keywords/Search Tags:Slurry Bubble Column Reactor, DGD, Gas Holdup, γ-ray Tomography, Large Bubble, Small Bubble, Bubble Population Rising Velocity
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