Decarbonizing cement industry via solar-hybrid capture: Synergistic Integration of microalgae, amine scrubbing, and direct air capture for enhanced energy and exergoeconomic performance

Global warming has emerged as one of the most critical environmental challenges of the 21st century. In response, the development and implementation of advanced carbon capture technologies have gained global attention. Among the major contributors to CO₂ emissions are cement production facilities, which not only release significant amounts of carbon dioxide but also degrade air quality due to their industrial exhaust. This study investigates the integration of three promising carbon capture approaches—chemical (amine-based post-combustion capture), biological (microalgae), and direct air capture (DAC)—with a focus on mitigating emissions from cement plant operations. Two hybrid scenarios are evaluated: (1) amine-based post-combustion capture combined with DAC and powered by solar energy (PCC+DAC+Solar), and (2) microalgae-based capture integrated with DAC and solar energy (Algae+DAC+Solar). A comprehensive energy, exergy, and economic analysis was conducted for both scenarios. Results indicate that the Algae+DAC+Solar system reduces electricity consumption by approximately 2 MW compared to the PCC+DAC+Solar configuration. However, in terms of exergy performance, the PCC+DAC+Solar system demonstrates a 7% higher exergy efficiency than the algae-based alternative. Furthermore, exergoeconomic evaluation reveals that both hybrid systems outperform single-technology approaches, with the Algae+DAC+Solar configuration achieving an exergoeconomic factor of 63%, and the PCC+DAC+Solar system reaching 60%.