Effect of different nitrogen ratio on the performance of CO₂ absorption and microalgae conversion (CAMC) hybrid...

CO₂ absorption hybrid with microalgae conversion (CAMC) could be a promising alternative for the conventional CO₂ capture technologies. The hybrid process could avoid the challenges of thermal energy consumption in the conventional desorption process and nutrition consumption in the typical algae cultivation process. In this work, the influence of different nitrogen ratio (NH₄HCO₃:NaNO₃) on the performance of the proposed hybrid CAMC process was investigated. Experimental results indicated that adding NH₄HCO₃ into cultivation solution could promote Spirulina platensis growth. When the ratio of NH₄HCO₃ and NaNO₃ was set at 1:4, carbon utilization efficiency of the hybrid process could achieve 40.45%, which was higher than the conventional microalgae CO₂ fixation processes (around 10%-30%). In addition, carbon sequestration capacity increased to 178.46 mg/L/d. It could be observed that CO₂ absorption-microalgae conversion (CAMC) hybrid system has the potential for cost-effective CO₂ capture and utilization.