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

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.