Carbon Capture and Storage to Simultaneous Biogas Purification and Precipitated Calcium Carbonate Production Using Ca(OH)₂ Aqueous Solution in A Bubble Column Reactor

Anaerobic digestion in biogas industry is associated to the production of several greenhouse gases, namely carbon dioxide, methane and nitrous oxide. As a consequence, dedicated measures should be taken in order to reduce these emissions. Efforts to limit the increase in atmospheric CO₂ concentrations while meeting increasing global energy demand can only be achieved by implementing a comprehensive technology portfolio, such as carbon capture and storage (CCS) measures. In this work, CCS technology was applied to remove CO₂ in biogas with Ca(OH)₂ aqueous solution using a continuous bubble column reactor. The bubble column with diameter D=13.95 cm and the ratio of liquid height to diameter H/D=4. The raw biogas was introduced into the bottom of the column to flow upward, while the Ca(OH)₂ aqueous solution introduced into the top to flow downward. It was found that CO₂ removal increases with decreasing the ratio of the superficial velocity of biogas to the superficial velocity of the Ca(OH)2 aqueous solution. About 70% CO₂ removal is achieved at the ratio of the superficial velocity of biogas to the superficial velocity of the Ca(OH)₂ aqueous solution of 0.4. The obtained PCC showed dominant morphology identical with calcite which is rhombohedral or cube form calcite with a size range of 600 - 1000 nm.