光生物反应器内CO2传输与微藻固碳性能强化

CO₂气体可为微藻光合作用提供必需的碳源，CO₂在藻液中的混合、溶解及传输特性显著影响了微藻的生长固碳.在微藻光生物反应器中，气泡在藻液中的生长、脱离、聚并、上升等动力学行为主要由气体分布器决定.本文以气体分布器为研究对象，研究在不同孔径及孔间距下对15%（V/V）CO₂气体在悬浮液中的气泡行为、CO₂溶解与混合特性以及对微藻生长固碳的影响.结果表明：气泡上升速度随气体分布器孔径及孔间距的减小而减小，导致CO₂气泡在藻液中停留时间增加，强化了CO₂溶解传输，CO₂体积传质系数提高了143%，混合时间降低了24%，最终使微藻生物质浓度提高18.8%，固碳速率提高23.2%.

Enhancement of CO2 transfer and carbon fixation by microalgae in photobioreactor

Gaseous carbon dioxide can provide an essential carbon source during microalgal photosynthesis. Mixing, dissolution and transportation characteristics of carbon dioxide have significant impacts on the growth of microalgae. In a photobioreactor, the behaviors of carbon dioxide bubbles during growth, detachment, coalescence and rising are significantly affected by the gas distributor. In this study, the effects of orifice diameter and spacing of the gas distributor on 15% CO₂ bubble behaviors, dissolution and mixing characteristics of carbon dioxide as well as performances of microalgal growth and carbon dioxide fixation have been investigated. The rising velocity of bubble was reduced with decreasing orifice diameter and spacing, thereby increasing the retention time of carbon dioxide in microalgal suspension. As the parameters of gas distributor were optimized, the gas-liquid mass transfer coefficient was improved by 143%, the mixing time was reduced by 24%, the concentration of microalgae was increased by 18.8%, and the carbon dioxide fixation rate was enhanced by 23.2%.