Application of CFD simulation for optimisation of the multi-pipe gas distributors in a large-scale shallow bubble column
Journal Title: Science Paper Online - Year 2008, Vol 3, Issue 12
Abstract
It has been generally acknowledged that the configuration of a gas distributor has significant impact on fluid dynamics and mixing in shallow bubble column reactors. This study employs computational fluid dynamics (CFD) -based models to simulate transient gas-liquid flow in a large-scale shallow cylindrical bubble column of 800 mm in diameter at the superficial gas velocity of 0.1 m/s. An Eulerian-Eulerian two-fluid model along with the stand k-ε turbulence model is adopted to simulate flow generated by gas sparged through five different multiple-pipe gas distributors which the four pipes are uniformly mounted at different distribution rings with ring to bubble column diameter ratios of 0.3, 0.4, 0.5, 0.6 and 0.7. Multiple-Size-Group (MUSIG) model is also employed in the simulation to account for bubble break-up and coalescence. The effects of the diameter of distribution rings for allocating gas sparging pipes in the gas distributor on hydrodynamics, gas hold-up, mixing, turbulence and bubble size is systematically investigated. The simulation results clearly show that gas hold-up and mixing characteristics in the bubble column are affected by the ring to bubble column diameter ratio. It is demonstrated that the mixing time and overall gas hold-up increase with the increase of ring to bubble column diameter ratio initially but decrease with further increasing such ratio. It is found from the simulation that the optimum ring to bubble column diameter ratio is about 0.4 for the best gas hold-up distribution and such a ratio of 0.5 corresponds the longest mixing time. The CFD modelling results also reveal that the flow pattern inside the bubble column is dominated by single circulation when ring to bubble column diameter ratio is smaller than 0.5 while double-circulation flow appears when the ratio is larger than 0.5, thus impairing the mixing in the bubble column. A comparison has been presented between the simulation and the experimental data.
Authors and Affiliations
Guang LI , Xiaogang YANG , Qingbai CAI, Gance DAI
Keywords
Related Articles
- EP ID EP118588
- DOI -
- Views 104
- Downloads 0
一种新型的毫米波谐振系统
提出一种新型的毫米波谐振系统，该系统由基片集成波导谐振器与多个λ/4驻波谐振器通过磁耦合而成为一个整体。多个λ/4谐振器的谐振频率与相位受基片集成波导谐振器控制。这种毫米波谐振系统的优点是：损耗小，品质因数高，与晶圆级封装( wa...
牛磺酸拮抗锰诱导体外培养的皮层神经细胞凋亡
【目的】研究牛磺酸对锰诱导体外培养的皮层神经细胞凋亡的拮抗作用。【方法】体外分离新生乳大鼠皮层神经细胞，培养至最佳生长状态时进行实验。细胞随机分为7组，即对照组、染锰组（设有低、中、高3个剂量）、干预组（3组，培养液同时加...
Oxidation of anthracene by phthalic anhydride modified laccase
Laccase is modified with phthalic anhydride in order to improve its stability against high temperature and acidic pH in this paper. The modification ratio of amino lysine groups of laccase is determined as 63.8% using TN...
A novel soluble polyamide-imide from new fluorinated diamine
[1,4-bis(4-amino-3-trifluoromethylphenoxy)benzene (B)], a new fluorinated diamine monomer were synthesized in this paper. PAI(C) is prepared from the diamine (B) and trimellitic anhydride chloride (TMAC) by one-step meth...
阴离子交换树脂固相萃取分离纯化DNA
以330阴离子交换树脂为吸附材料建立了固相萃取分离DNA的方法。利用血红蛋白和树脂之间的静电作用力将DNA吸附至树脂，以Na2HPO4溶液为洗脱剂回收DNA．考察了溶液pH值、吸附时间和温度、洗脱剂的种类及其浓度等对分离纯化的影响。在优化实...