Synergizing carbon capture storage and utilization in a biogas upgrading lab-scale plant based on calcium chloride: Influence of precipitation parameters

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.

Keywords: Biogas upgrading; Calcium carbonate precipitation; Carbon capture and utilization; Chemical absorption.