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

Abstract

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.