CO2 Dissolution and Design Aspects of a Multiorifice Oscillatory Baffled Column

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• 作者：Filipa M. Pereira ; Diana Z. Sousa ; M. Madalena Alves ; Malcolm R. Mackley ; Nuno M. Reis
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：November 5, 2014
• 年：2014
• 卷：53
• 期：44
• 页码：17303-17316
• 全文大小：689K
• ISSN：1520-5045

文摘

Dissolution of CO₂ in water was studied for a batch vertical multiorifice baffled column (MOBC) with varying orifice diameters (d₀) of 6.4鈥?0 mm and baffle open area (伪) of 15鈥?2%. Bubble size distributions (BSDs) and the overall volumetric CO₂ mass transfer coefficient (K_La) were experimentally evaluated for very low superficial gas velocities, U_G of 0.12鈥?.81 mm s^鈥?, using 5% v/v CO₂ in the inlet gas stream at a range of fluid oscillations (f = 0鈥?0 Hz and x₀ = 0鈥?0 mm). Remarkably, baffles presenting large d_o = 30 mm and 伪 = 36%, therefore in the range typically found for single-orifice oscillatory baffled columns, were outperformed with respect to BSD control and CO₂ dissolution by the other baffle designs or the same aerated column operating without baffles or fluid oscillations. Flow visualization and bubble tracking experiments also presented in this study established that a small d_o of 10.5 mm combined with a small value of 伪 = 15% generates sufficient, strong eddy mixing capable of generating and trapping an extremely large fraction of microbubbles in the MOBC. This resulted in increased interfacial area yielding K_La values up to 65 卤 12 h^鈥? in the range of the U_G tested, representing up to 3-fold increase in the rate of CO₂ dissolution when compared to the unbaffled, steady column. In addition, a modified oscillatory Reynolds number, Re_o^{鈥?/sup> and Strouhal number, St鈥?were presented to assist on the design and scale-up of gas鈥搇iquid systems based on multiorifice oscillatory baffled columns. This work is relevant to gas鈥搇iquid or multiphase chemical and biological systems relying on efficient dissolution of gaseous compounds into a liquid medium.}