碱性阴离子交换膜燃料电池用于消除微藻固碳过程中溶氧效应的实验研究

An Experimental Study on the Dissolved Oxygen Consumption with Alkaline Anion-Exchange Membrane Fuel Cell

针对微藻固碳过程中藻液产生的高浓度溶氧会抑制藻细胞生长、降低CO2固定效率的问题,搭建了管式光生物反应器实验台用于藻类的高效培养和固碳,提出了利用电化学方法抑制藻液中溶氧效应的研究思路。首先开展管式光生物反应器培养小球藻的实验研究,对比了光生物反应器与锥形瓶2种培养装置对小球藻生长特性的影响,其次实验研究了利用碱性阴离子交换膜燃料电池的阴极氧还原反应去除藻液中的溶解氧。结果表明:管式光生物反应器运行10个周期之后,微藻的质量浓度达到769 mg/L,生物量增长了10倍,培养效果明显优于锥形瓶培养;经过系统持续运行4 h之后,藻液中的溶氧量由18.35 mg/L降低到6.19 mg/L,溶氧消耗效率为66.3%,电池的最大功率密度达到81 W/m^2。研究证明,采用燃料电池的阴极电化学反应可以实现藻液中溶解氧快速有效地消耗,这一方面提升了微藻的固碳效率,另一方面输出了电能,降低了系统能耗。

A tubular photobioreactor for efficiently cultivating chlorella is designed and built to solve the problem that the high concentration of dissolved oxygen generated in the microalgae solution would inhibit the growth of algal cells and reduce the efficiency of CO2 fixation.A new perspective idea is proposed to remove the dissolved oxygen in the microalgae suspension with electrochemical method.Results indicate that the tubular photobioreactor performs better than Erlenmeyer flask on chlorella cultivation.The concentration of chlorella reaches 769 mg/L after 10 cultivation cycles,and it is ten times of the initial concentration.By employing the anion-exchange membrane direct glucose duel cell(AEM-DGFC)with Pt-free electrodes to consume the dissolved oxygen in the microalgae suspension for 4 hours,the dissolved oxygen content decreases from 18.35 mg/L to 6.19 mg/L,and the dissolved oxygen content reduces by 66.3%.In addition,the peak power density of AEM-DGFC reaches 81 W/m^2,which is superior to the cell with pure oxygen as the oxidant in the cathode.It is concluded that by the aid of AEM-DGFC,the dissolved oxygen is consumed efficiently.On the other hand,the electric energy is output and the energy consumption of the system is reduced.