Abstract
Herein a strategy for biogas upgrading in a continuous flow absorption unit using CaCl2 as capturing agent is reported. This process is presented as an alternative to the standard physical regeneration processes to capture carbon dioxide (CO2) from biogas effluents with inherent high energy penalties. This work showcases a systematic study of the main parameters (reaction time, reaction temperature, and molar ratio reactant/precipitator) affecting calcium carbonate (CaCO3) precipitation efficiency in a reaction between sodium carbonate (Na2CO3) and CaCl2. In addition, the purity and main characteristics of the obtained product were carefully analysed via in a combined characterization study using Raman, XRD, and SEM. Our results indicate that acceptable precipitation efficiencies between 62 and 93% can be reached by fine tuning the studied parameters. The characterization techniques evidence pure CaCO3 in a calcite structure. These results confirmed the technical feasibility of this alternative biogas upgrading process through CaCO3 production.