Bio-regeneration of different rich CO absorption solvent via microalgae cultivation.

As one of the most mature carbon capture technologies, thermal regeneration of rich CO absorption solvent is a crucial challenge due to its high energy consumption (typically in the range of 3-6 MJ/kg CO). In this work, a concept of bio-regeneration was proposed using microalgae to convert bicarbonate (which is one of the dominant components in rich solution) into value-added biomass. To evaluate the performance of bio-regeneration, different rich solution (including NHHCO, KHCO and NaHCO) were investigated. Experimental results indicated that NHHCO could be a promising bicarbonate carrier for the proposed absorption-microalgae hybrid process, which had a higher biomass productivity (55.36 mg·L·d) compared to KHCO and NaHCO and carbon sequestration capacity could be up to 158.3 mg·L·d. Meanwhile, pH adjustment was an effective approach to further intensify the performance of hybrid process. As a result, bio-regeneration of solvents could be a promising alternative to the conventional thermal regeneration.